BUILDING PERFORMANCE: HURRICANE INIKI IN HAWAII
Observations, Recommendations, and Technical Guidance
Learning from failure, building on success
Teaming to Reduce Future Damages
Federal Emergency Management Agency
Federal Insurance Administration
In Cooperation with the State of Hawaii Office of Civil Defense and Kauai County
FIA-23, 3/93


TABLE OF CONTENTS 

EXECUTIVE SUMMARY 1 

1.0 INTRODUCTION 5
 1.1 Purpose 5 
 1.2 Background 5 
 1.3 The Building Performance Assessment Team 6 
  1.3.1 Team Composition 7 
  1.3.2 Purpose of the Team 7 
  1.3.3 Team Activities 8 
  1.3.4 The "Team" Concept 8 
 1.4 Hurricane Iniki -Storm Conditions 9 
 1.5 National Flood Insurance Program Requirements 11 
 1.6 Building Code Requirements for Wind Hazards 12 

2.0 OBSERVATIONS OF FLOOD DAMAGE AND COASTAL FLOODPLAIN CONSTRUCTION 15 
 2.1 Kekaha 15 
 2.2 Poipu Beach 17 
 2.3 Conclusions 28 

3.0 OBSERVATIONS OF WIND DAMAGE AND SUCCESSFUL BUILDING PERFORMANCE UNDER WIND 
LOADING CONDITIONS 31 
 3.1 Field Sites 31 
 3.2 Observations of Building Performance under Wind Loading 32 
 3.3 Diagnostic Modes of Structural Failure 33 
 3.4 Diagnostic Modes of Successful Structural Performance 44 
 3.5 Roof Sheathing 47 
 3.6 Roof Cladding 52 
 3.7 Glazing and Transparent Openings 54 
 3.8 Windborne Debris 60 
 3.9 Deterioration 62 
 3.10 Pre-Engineered Steel Warehouses 62 

4.0 RECOMMENDATIONS 67 
 4.1 Floodplain Management and Flood Damage 67 
 4.2 Wind Damage and Wood-Frame Construction 80 
 4.3 Glazing and Transparent Structural Openings 92 
 4.4 Roofing 95 
 4.5 Building Permitting, Plan Review, and Inspection 95 
 4.6 Training and Education 97 
 4.7 Repair/Retrofit of Partially Damaged and Undamaged Buildings 98 

LIST OF TABLES 

Table 1. Residential Buildings Substantially Damaged by Flooding at Poipu Beach 
18 


LIST OF FIGURES 

Figure 1. The eye of Hurricane Iniki crossed the Kauai coast just west Port 
Allen near Kaumakani just before 4:00,p.m. Hawaiian Standard Time on September 
11,1992. 6 

Figure 2. Hurricane Iniki produced substantial wind speeds at low altitudes in 
excess of the 80-mph base condition. 11 

Figure 3. Portion of Flood Insurance Rate Map (FIRM) for Kauai County covering 
the Poipu Beach area. 13 

Figure 4. Various flood hazard zones, including velocity (V) Coastal High Hazard 
zones, on the Kauai County FIRM (Hanalei example). 13 

Figure 5. Flood damage to this coastal house in Kekaha was minimized because the 
house is elevated 2 to 3 feet off the ground and is located a considerable 
distance from the shoreline. 16 

Figure 6. Results of preliminary field inventory of damaged residential 
buildings -Poipu Beach Park to Spouting Horn Park. 18 

Figure 7. Waterborne debris resulted in significant damage to non-elevated 
buildings along Poipu Beach. 19 

Figure 8. Typical example of residential construction along Poipu Beach that was 
destroyed because it was not elevated above the flood hazard. 20 

Figure 9. Non-elevated house at Poipu Beach that floated off its foundation and 
was transported well inland. 20 

Figure 10. Non-elevated house at Poipu Beach that floated off its foundation was 
pinned against another house and destroyed by waves. 21 

Figure 11. Non-elevated building at Poipu Beach that rammed and increased damage 
to an adjacent building. 22 

Figure 12. Non-elevated building at Poipu Beach destroyed by coastal flooding. 
22 

Figure 13. Non-elevated building at Poipu Beach destroyed by coastal flooding. 
23 

Figure 14. Interior of non-elevated building at Poipu Beach destroyed by coastal 
flooding. 23 

Figure 15. Foundation at Poipu Beach undermined by erosion. 25 

Figure 16. Undermining of shallow pier foundation at Poipu Beach due to lack of 
sufficient embedment below erosion depth. 25 

Figure 17. Breakup of grouted lava rock walls at Poipu Beach generated 
waterborne projectiles. 26 

Figure 18. Waterborne lava rock projectiles at Poipu Beach increased damage to 
non-elevated buildings. 26 

Figure 19. Non-elevated buildings at Poipu Beach. 29 

Figure 20. Typical non-elevated condominium or hotel. 29 Figure 21 Once the roof 
system is compromised, the ability of the wood-frame exterior walls to withstand 
external wind pressure is greatly diminished. 34 

Figure 22. Roof rafter construction with simple nailing or toenailing failed 
under uplift forces. 35 

Figure 23. Toenailing of ridge beam to gable-end support. 35 

Figure 24. Toenailing of rafter to ridge beam. 36 

Figure 25. Toenailing of roof rafters to wall system. 36 

Figure 26. Example of improperly sized and placed metal fastener, which led to 
roof failure from wind uplift forces. 37 

Figure 27. Undersized and improperly attached metal fasteners led to roof damage 
from uplift forces. 39 

Figure 28. Individual prefabricated wood roof trusses performed relatively well. 
39 

Figure 29. Gable-end roof failure due to loss of roof sheathing and lack of 
gable bracing. 40 

Figure 30. Improper connection (toenailing) between roof trusses and wall 
systems 41 

Figure 31. Gable-end roof designs tended to be more failure-prone. 41 

Figure 32. Low-pitched hip roofs are aerodynamically superior and generally 
performed better than steeply pitched gable-end roofs. 42 

Figure 33. Offset roof peak provides geometric discontinuity and results in 
greater localized wind-induced pressure, which can lead to roof and then wall 
failure. 42 

Figure 34. Excessive roof overhang and poor connections in many instances led to 
roof failure. 43 

Figure 35. Example of very successful heavy-gauge metal fastener connecting roof 
and wall systems. 45 

Figure 36. Wood splice or strap provides a secure connection between wall and 
roof systems. 45 

Figure 37. Sensitive craftsmanship and attention to detail. 46 

Figure 38. Improper attachment of sheathing to purlins. 47 

Figure 39. Improper nailing -design and schedule for purlin-to-rafter 
attachment. 48 

Figure 40. Loss of roof sheathing due to improper nailing design and schedule. 
48 

Figure 41. Total roof failure due to loss of sheathing. 50 

Figure 42. Failure of corrugated metal roof at attachment points. 50 

Figure 43. Metal roof loss generates large airborne projectiles, which often 
cause additional damage. 51 

Figure 44. Loss of roof cladding due to failure at attachment points. 53 

Figure 45. Heavy concrete tile attached at one point with undersized 
nail. 53 

Figure 46. Roof cladding systems composed of interdependent elements. 55 

Figure 47. Glazing broken by windborne debris or direct wind pressure. 55 

Figure 48. Loss of opening protection allows wind entry and increases internal 
exposure. 56 

Figure 49. Implosion of transparent shatter-resistant sliding door. 56 

Figure 50. Improper attachment of window unit. 57 

Figure 51. Improper connection of sliding glass door. 58 

Figure 52. Gable-end window unit as a whole was displaced inward 
by wind pressure. 58 

Figure 53. Extensive use of glazing on windward side can significantly 
compromise a building's envelope and lead to roof failure. 59 

Figure 54. In-place protective devices for glazing reduced the occurrence of 
building envelope failures. 60 

Figure 55. Windborne debris impact can puncture building and allow buildup of 
internal wind pressure. 61 

Figure 56. Steel warehouse failure commonly was due to loss of light-gauge metal 
sheet cladding. 63 

Figure 57. Steel warehouse failure was also due to failure of structural steel 
members. 63 

Figure 58. Failure of steel warehouse due to age and weatherization 
and insufficient anchorage to resist uplift. 64 

Figure 59. Steel warehouse, sill-to-concrete-foundation failure at anchoring 
points. 64 

Figure 60. NFIP requirements for elevated foundations in V zones. 68 

Figure 61. One method of support for piers is a reinforced concrete footing. 69 

Figure 62. Drilled pier foundation. 70 

Figure 63. Reinforced concrete pier. 70 

Figure 64. Reinforced concrete masonry pier. 71 

Figure 65. Reinforced brick pier. 71 

Figure 66. Posts are placed into pre-dug holes and may be anchored in a concrete 
pad at the bottom of the hole 72 

Figure 67. Posts can also be anchored in concrete encasements. 73 

Figure 68. Post on concrete bearing pad. 74 

Figure 69. Post on concrete bearing pad. 74 

Figure 70. Post in concrete backfill. 75 

Figure 71. Post on earth bearing. 75 

Figure 72. Spike anchorage of post. 76 

Figure 73. Galvanized strap anchorage of post. 76 

Figure 74. Pilings are mechanically driven into the ground, making them less 
susceptible to velocity flooding, scour, and pullout. 77 

Figure 75. The depth of pile embedment provides stability to resist lateral and 
vertical loads through passive earth pressures. 78 

Figure 76. Post/pile foundation. 78 

Figure 77. Recommended wood-frame construction. 81 

Figure 78. Typical roof truss top chord bracing. 82 

Figure 79. Detail A- Typical web bracing. 82 

Figure 80. Detail B- Typical wood gable-wall bracing with nailed connections. 83 

Figure 81. Typical hurricane strap to roof framing detail 84 

Figure 82. Recommended hip roof framing. 85 

Figure 83. Hip roof framing connectors. 86 

Figure 84. General notes for Figures 85-87. 88 

Figure 85. Existing "single wall" on slab-on-grade 89 

Figure 86. Existing "single wall" on existing concrete masonry unit wall 90 

Figure 87. Existing "single wall" on new concrete masonry unit wall and footing. 
91 

Figure 88. Prefabricated storm shutters. 92 

Figure 89. Previously purchased plywood stored for use as openings protection 
during storm conditions 93 

Figure 90. Plywood used as openings protection installed. 93 

Figure 91. Typical installation of plywood openings protection for wood-frame 
building. {o 94 

Figure 92. Tips for galvanized roofing. 96 

APPENDIX A 
Building Performance Assessment Team Members and Advisors 99 








EXECUTIVE SUMMARY 

On September 22, 1992, at the request of the Mayor of Kauai County, the Federal 
Coordinating Officer for the Iniki disaster tasked the Federal Emergency 
Management Agency's (FEMA's) Federal Insurance Administration (PIA) to assemble 
a team of experts to assess the performance of buildings. Since the 1970s, PIA 
has gained valuable experience through an ongoing assessment program that 
focuses on the performance of buildings that have incurred flood damage. In 
addition, PIA's National Flood Insurance Program establishes regulations for the 
reconstruction of substantially damaged buildings in floodplains, regardless of 
the cause of the damage. 

For the Iniki disaster, the team assembled by PIA included FEMA Headquarters and 
Regional staff, representatives of the State of Hawaii Office of Civil Defense 
and Kauai County, and Registered Professional Engineers and Architects from both 
Kauai and Oahu (see Appendix A for complete list). The team was tasked with 
surveying the performance of primarily residential structures under wind and 
water forces generated during Hurricane Iniki. The goal of this effort is to 
provide guidance and offer recommendations for reducing damage from future 
hurricanes. This goal is best met through learning from both failures and 
successes of building performance. 

During the field assessment, the team investigated primary structural systems, 
i.e., systems in a building that resist lateral and vertical forces. For all 
buildings, the performance of exterior architectural systems, such as roofing, 
windows, and doors was analyzed. The analysis also included the effects of 
windborne and waterborne debris and the quality of construction and materials. 
The majority of building types observed were one- and two-story, wood-frame, 
single-family and multi-family residential structures. However, pre-engineered 
steel commercial and industrial buildings, as well as resort hotels and 
condominiums constructed of reinforced concrete and masonry, were also examined. 

WIND FORCES 

Noteworthy examples of adequately engineered and constructed buildings were 
observed in Kauai County. Almost without exception, successful performance 
resulted from clearly defined and continuous "load transfer paths" from the roof 
to the foundation. A well-designed load transfer path depends primarily on the 
proper type, sizing, and attachment of connections between the critical 
components of a building (for example, between the roof and walls and between 
the walls and foundation). Where connections, such as hurricane clips and metal 
straps on wood-frame structures, were adequately sized and correctly applied, 
buildings performed relatively well. 

Incomplete design and construction for load transfer and improper connections, 
especially between the roof and walls, were found to be the most important 
factors causing structural failure of buildings due to uplift wind forces. 
Consistently, a building's structural integrity was compromised through the 
action of uplift forces on insufficiently designed and connected roof and wall 
systems. Loss of roof cladding (e.g, shingles), roof sheathing (e.g., plywood), 
and other building attachments provided a source of airborne projectiles which 
contributed to the overall damage. In many instances, loss of glazing (e.g., 
glass doors and windows), either from direct wind pressure or from debris 
impact, resulted in a breach of the building envelope, subsequent internal 
pressures, and progressive structural failure. 

Much of the damage to structures caused by wind forces resulted from incomplete 
design, reliance on outdated methods of workmanship, and/or misapplication of 
various building materials. Many of these problems can be addressed by training 
and education programs that promote prudent building design and construction 
practices throughout Kauai County. This is especially true for buildings in 
bluff and oceanfront areas exposed to accelerated wind forces. 

FLOOD FORCES 

In coastal floodplains and Coastal High Hazard Areas, the obvious primary cause 
of building failure was direct wave impact (hydrodynamic forces) on buildings 
whose lowest floors had been constructed directly on the ground surface. Low-
lying, oceanfront buildings, situated somewhat landward of the shoreline and 
having lowest floors elevated above the flood hazard, fared much better than 
ground-level buildings immediately adjacent to the shoreline. Waterborne debris 
such as lava boulders and debris from damaged non-elevated buildings increased 
damage to adjacent buildings. 

RECOMMENDATIONS 

Recommendations presented in this report can be summarized as follows: 

- Provide adequate means and methods to ensure the structural integrity of a 
building by constructing properly engineered buildings which consider the 
continuous load transfer path of a structure from roof to foundation. To ensure 
the integrity of the structure's load transfer path, metal /' fasteners 
("hurricane clips") and straps must be adequately sized and properly installed. 

- Design all architectural elements to resist the same wind forces as the 
primary structural systems. 

- Construct and properly engineer buildings such that they protect, or contain 
adequately designed, glasswork in exposed areas; adhere to nailing and 
attachment requirements for roof sheathing, roof cladding, and windows and 
doors; and provide routine maintenance of building components, including repair 
and replacement of damaged elements. 

- In areas subject to flooding, elevate buildings above predicted flood heights 
on properly designed and constructed foundations. Minimize the sources of future 
debris by appropriately designing and locating site improvements such as stone 
walls. 

- Provide a program of training and continuous education to code enforcement 
officials, plan reviewers, inspectors, supervisors, and others who are charged 
with implementing the recommendations noted above. Provide companion training 
and education programs for homeowners, building contractors, and design 
professionals in the proper construction techniques for mitigation of wind and 
flood hazards. 

- Trade associations, labor associations, etc., should provide continuing 
education programs for updating their members concerning revisions to Building 
Codes under which they are performing their trades. 

This report includes detailed engineering discussions of building failure modes 
and successful building performance. It also provides detailed recommendations 
for enhancing building performance under hurricane and flood conditions. 

1.0 INTRODUCTION 

1.1 PURPOSE 

The purpose of this report is to provide guidance and recommendations for 
reducing hurricane and flood damage in the future. This purpose is best achieved 
through learning from successes and failures of building performance. Therefore, 
this report includes observations of both successes and failures of various 
building types. 

Numerous references to figures are made throughout the text of this report. 
These figures, primarily photographs, explicitly portray, clarify, or reinforce 
the technical issues addressed. The figures are presented at the end of each 
pertinent section. The reader is encouraged to examine these figures while 
reviewing the report. 

This report includes detailed engineering discussions of building failure modes 
and successful building performance supplemented by graphic examples and 
illustrated design specifications. It also provides recommendations for 
enhancing building performance under hurricane conditions and addressing 
building materials, code compliance, plan review, and construction inspection. 

1.2 BACKGROUND 
In the afternoon of September 11, 1992, Hurricane Iniki struck the Island of 
Kauai, Hawaii, generating high winds and storm surge over a vast area of the 
island (FIGURE 1). With wind speeds exceeding those of Hurricanes Iwa (1982) and 
Dot (1959), Iniki was the strongest and most destructive hurricane to strike the 
Hawaiian Islands in recent memory. 

[Begin figure]
FIGURE 1. The eye of Hurricane lniki crossed the Kauai coast just west of Port 
Allen near Kaumakani just before 4 :OO p.m. Hawaiian Standard Time on September 
11, 1992. 
{End figure]

Although measurements of the storm's wind speeds are subject to continuing 
analysis, it was evident from the extensive damage observed that wind speeds 
were significant. Preliminary measurements of coastal flooding and deposition of 
heavy debris considerable distances inland are evidence of the significant storm 
surge and wave forces associated with the hurricane. 

1.3 THE BUILDING PERFORMANCE ASSESSMENT TEAM 

On September 22, 1992, following a request from the Mayor of Kauai County, the 
Federal Coordinating Officer for the lniki disaster tasked the Federal Insurance 
Administration (PIA) to assemble a team of experts to assess the performance of 
buildings. Since the 1970s, PIA has gained valuable experience through an 
ongoing assessment program that focuses on the performance of buildings that 
have incurred flood and wind damage. These assessments evaluate and support 
PIA's administration of the National Flood Insurance Program (NFIP), which 
includes enforcement of requirements governing the reconstruction of 
substantially damaged buildings in floodplains, regardless of the cause of the 
damage. 

1.3.1 TEAM COMPOSITION 

The team included field-experienced professionals trained in building design and 
construction and a cadre of technical and policy advisors. Team members that 
participated in the field surveys were Federal Emergency Management Agency 
(FEMA) Headquarters and Region IX staff, representatives of the State of Hawaii 
Civil Defense System and the Kauai County Engineering and Planning Departments, 
and Registered Professional Engineers and Architects from both Kauai and Oahu 
(see Appendix A for complete list). 

1.3.2 PURPOSE OF THE TEAM 

The purpose of the team was to evaluate the effectiveness of past design and 
construction practices in Kauai County by surveying damage (or lack of damage) 
caused by Hurricane Iniki. From field assessments of building systems subjected 
to significant wind and/or water forces, the team sought to diagnose 
characteristic modes of building system failure and to identify the systems that 
were successful in resisting those forces. Through this preliminary report and 
associated training activities, the team also will offer recommendations and 
guidance on ways to reduce similar damage in the future. 

The basis for forming the team, compiling this report, and pursuing further 
study is the assumption that improved performance of buildings can be attained 
when: 

- observed failure modes can be mitigated using basic and widely recognized 
practices and standards for new and repair construction; 

- observed building successes can be used as evidence to reinforce the use of 
these practices and standards; and 

- Federal, State, and County governments and the private sector work in close 
cooperation to ensure that repair work and new construction practices will 
mitigate against future hazards while remaining cost- effective and practical. 

1.3.3 TEAM ACTIVITIES 

During the field assessment, the team investigated primary structural systems, 
i.e., systems that support a building under lateral and vertical loading 
conditions. The majority of building types observed were one- and two-story 
wood-frame structures - single-family residential, multi-family residential, and 
commercial. However, the team attempted to be comprehensive by assessing a wide 
range of construction types (including metal-frame pre-engineered commercial and 
industrial structures and resort hotels and condominiums constructed of 
reinforced concrete and masonry). These structures were observed in locations 
experiencing a wide range of wind and flood exposure conditions. 

Collectively, the team invested a significant number of man-hours in the site 
surveys, documentation, assessment of damages, formulation of recommendations, 
and report production. Documentation of findings made during ground-level and 
aerial surveys included field notes, photographs, and videotaping. 

1.3.4 THE "TEAM" CONCEPT 

Participation by State and County governmental officials and locally based 
consulting Engineers and Architects in the assessment process is critical 
because it 1) ensures that all State and local Building Code and other 
requirements are properly interpreted, 2) enhances the likelihood that local 
construction practices are fully appreciated and understood, 3) helps establish 
positive relationships between Federal, State, and local governments and the 
private sector, and 4) encourages recommendations that are realistic, from both 
economic and technical standpoints. 

Under the "team" concept, local government and its citizens become active 
participants in a positive and forward-looking technical appraisal and planning 
process which attempts to improve the future performance of buildings. In this 
way, team recommendations have a much better likelihood of being considered, 
adopted, and implemented. 

1.4 HURRICANE INIKI -STORM CONDITIONS 

Hurricane Iniki was a small but intense hurricane as it moved northward across 
the Island of Kauai during the late afternoon hours of September 11,1992. The 
eye of Iniki crossed the Kauai coast just west of Port Allen near Kaumakani just 
before 4:00 p.m. Hawaiian Standard Time (HST). Iniki left behind a path of 
destruction, with property damage expected to approach 1.8 billion dollars. On 
Kauai alone, Iniki destroyed or damaged 14,350 homes. Of that total, 1,421 were 
destroyed and another 5,152 suffered major damage. Damage on Kauai was 
widespread, with the most severe damage occurring on the south, east, and north 
ends of the island. Even with such widespread and severe damage, only three 
deaths were attributed directly to the storm. The low loss of life can be 
attributed to ample warning time, an excellent response by the State of Hawaii 
Office Civil Defense System, the evacuation of all coastal areas, and the high 
level of awareness created by previous press coverage of Hurricane Andrew in 
Florida and Typhoon Omar in Guam. 

As expected from a hurricane of Iniki's intensity, coastal flooding was 
significant along the southern shoreline from Kekaha to Poipu Beach. Coastal 
flood heights were measured along the southern shoreline by the U.S. Army Corps 
of Engineers (COE), Pacific Ocean Division, under contract to FEMA. Although 
measurements are preliminary and require verification, they indicate stillwater 
flood elevations ranging from 10.5 to 12.5 feet above mean lower low water 
(mllw) at Kekaha to 12.5 to over 20 feet above mllw along Poipu Beach. An 
independent assessment conducted by the Department of Geology and Geophysics, 
University of Hawaii, confirms the magnitude and extent of the surge heights and 
penetration. 

A determination of actual wind speeds during Hurricane lniki proved to be highly 
variable. This may be due to varying degrees of exposure as a result of ground 
surface irregularities, the distance between anemometer ( a gauge for recording 
wind velocity) sites, and the potential inaccuracy of anemometers at excessively 
high winds. Wind speeds were recorded at the Pacific Missile Range Facility at 
Barking Sands, Lihue Airport, and one other station on the island. The strongest 
winds were reported from Port Allen eastward, with Makahuena Point reporting 
east winds at 70 knots (81 mph), with gusts to 105 knots (121 mph) when the 
power failed. The peak gust at Makahuena Point, which was extracted from the 
data recorder after the fact, reached 124 knots (143 mph). At Lihue Airport, the 
strongest sustained wind was southeast at 84 knots (97 mph) at 3:52 p.m. HST and 
southwest at 78 knots (90 mph) at 5:10 p.m. HST. These wind speeds, however, do 
not account for higher wind speeds that may have existed along highly exposed 
ocean promontories such as Makahuena Point or ocean-fronting high bluffs such as 
at Princeville. Wind speeds can also be amplified above these actual recorded 
base conditions by channeling through mountain gorges or as a result of the 
effects of other landforms with extreme topography. 

On October 8, 1992, members of the team met with various experts involved in the 
assessment of the winds generated by Iniki. The team learned that the sustained 
wind speeds at low altitude were recorded in excess of the 80-mph basic code 
design (FIGURE 2). However, it is important to understand that the basic wind 
speed of Hurricane Iniki was not beyond that which a building can be designed 
for with reasonable likelihood of successful performance. 

[Begin Figure]
FIGURE 2. Hurricane lniki produced substantial wind speeds at low altitudes in 
excess of the 80-mph base condition. 
[End Figure]

1.5 NATIONAL FLOOD INSURANCE PROGRAM REQUIREMENTS 

Currently, Kauai County is participating in the regular phase of the NFIP. 
County participation in the NFIP makes federally backed and reasonably priced 
flood insurance available to residents. As a condition of flood insurance 
availability, the county agreed to and has adopted regulations that meet or 
exceed NFIP minimum standards. The NFIP standards call for enforcement of 
prudent construction practices in flood hazard areas. These practices pertain to 
the construction of new and substantially improved buildings and to the repair 
of substantially damaged buildings in flood hazard areas as designated on the 
Flood Insurance Rate Map (FIRM). The cornerstone of the NFIP requirements is 
that the lowest floors of buildings must be elevated to or above flood heights 
shown on the FIRM. 

The flood hazard designated on the FIRM for southern Kauai is based on a hybrid 
system of the 100-year tsunami and wave runup recorded from Hurricane Iwa 
(1982). The 100- year tsunami is the basis for the rest of the State except for 
Southern Oahu. 

Along some oceanfront property such as Poipu Beach (FIGURE 3) and Hanalei 
(FIGURE 4), Coastal High Hazard Areas have been mapped. These areas are 
designated as V zones (velocity zones) on the FIRM. A V zone is an area subject 
to 100-year coastal flooding with waves 3 feet or greater in height. 
Consequently, additional design considerations are necessary for construction in 
V zones. Such considerations include use of pile and column foundations, leaving 
the area under the elevated building open to allow for free passage of velocity 
flood waters, and ensuring that foundation embedment is sufficient to withstand 
erosion and localized scour. 

[Begin figures]
Figure 3. Portion of Flood Insurance Rate Map (FIRM) for Kauai County covering 
the Poipu Beach area. Note predicted 100-year flood heights of 12 to 14 feet 
above mean sea level.

Figure 4. Various flood hazard zones, including velocity (V) Coastal High Hazard 
zones, on the Kauai County FIRM (Hanalei example).

Buildings in flood hazard areas that are determined to have been "substantially 
damaged" during Iniki, for whatever reason (e.g., wind or flood), must be 
repaired or reconstructed to NFIP standards for new construction. A building is 
substantially damaged when the cost to fully repair the building equals or 
exceeds 50 percent of its pre-damaged market value. 

1.6 BUILDING CODE REQUIREMENTS FOR WIND HAZARDS

Kauai County was, at the time of the hurricane, using the 1985 version of the 
Uniform Building Code (UBC). The UBC, in Chapter 23, "General Design 
Requirements," requires that buildings be "designed and constructed to resist 
the wind effects determined in accordance with the requirements of this 
section," this section being Section 2311, which deals with wind design. 
However, an exception is granted earlier in the Code, in Section 2303, "Design 
Methods," which states "Unless otherwise required by the building official, 
buildings or portions thereof which are constructed in accordance with the 
conventional framing requirements specified in Chapter 25 of this 
code shall be deemed to meet the requirements of this section." Chapter 25 of 
the 1985 UBC contains provisions which implicitly address the quality and design 
of wood members and their fastenings. 

On December 7, 1992, Kauai County adopted Appendix Section 2518 of Chapter 25 of 
the 1991 UBC, which specifically addresses design and construction of light-
frame timber buildings in high-wind areas. Appendix Section 2518 applies to 
regular-shaped buildings which have roof structural members spanning 32 feet or 
less, are not more than three stories in height, are of conventional light-frame 
construction, and are located in areas with a basic wind speed from 80 through 
110 miles per hour. This appendix addresses shortcomings in design and 
construction practices due to reliance on implicit provisions in the 1985 UBC. 
Appendix Section 2518 of the 1991 UBC is very explicit in its requirements and 
contains graphical presentations not contained in older versions of the Code. 
Compliance with Appendix Section 2518 will help reduce wind-related damages in 
the future, and the County is to be commended for this prudent action. 

2.0 OBSERVATIONS OF FLOOD DAMAGE AND COASTAL FLOODPLAIN CONSTRUCTION 

The team surveyed two areas on the island that experienced coastal flooding: 
Kekaha and Poipu Beach. 

2.1 KEKAHA 

Ageneral examination of flood damage was perfonned in the Town of Kekaha. The 
majority of flood damages sustained were to older, single-family, wood-frame 
structures, probably constructed during the 1920s to 1940s. While flood damages 
in Kekaha were minor compared to those in Poipu, and only a limited number of 
homes actually incurred flooding, two important observations were made. 

1. Damage to all but a few buildings was relatively minor, i.e., simple 
inundation with limited or no structural damage. The reduced flood damage 
resulted from the following: 

- Buildings were located a considerable distance (100-150 feet) from the 
shoreline. This buffer area allowed for dissipation of wave energy, which 
greatly reduced exposure of buildings to hydrodynamic forces. 

- Coastal flooding at Kekaha was less severe than flood heights at Poipu Beach. 
The COE preliminary estimates of flooding, based on surveyed sediment lines 
inside buildings (stillwater elevations) and debris lines on the ground, ranged 
from 10.5 to 12.5 feet mllw in the Kekaha area. 

- The lowest floors of some buildings were elevated above the ground surface. 
While the elevation was only 2 to 3 feet above grade on a crawlspace foundation, 
it was sufficient in this area to prevent water from entering several homes 
(FIGURE 5). 

[Begin figure]
FIGURE 5. Flood damage to this coastal house in Kekaha was minimized because the 
house is elevated 2 to 3 feet off the ground and is located a considerable 
distance from the shoreline. 
[End figure]

2. The vast majority, if not all, of the flood damage might have been prevented 
if the buildings had been elevated to or above the flood heights shown on the 
County's FIRM. Since these buildings are quite old, it is to be expected that 
they would not have been elevated above anticipated flood levels. Interestingly, 
as mentioned above, the lowest floors of some of the buildings had coincidently 
been elevated some 2 to 3 feet above the ground surface when the buildings were 
constructed. These buildings appeared to have suffered little to no damage from 
flood waters. 

Clearly, the flood damage sustained, and the flood damage prevented, in Kekaha 
reinforce the importance of properly elevating new and substantially improved 
construction above predicted flood levels in this and other flood hazard areas. 

2.2 POIPU BEACH 

A detailed damage survey was conducted in the section of PoipuBeach between 
Spouting Horn Park and Poipu Beach Park. The primary focus of this survey was 
single-family residential structures. Due to security and public safety issues, 
some damaged hotels and condominiums were not evaluated in great depth. However, 
with the permission of on-site security personnel, safe access was gained to 
other hotels and condominiums. From the resulting site analyses, observations 
and basic recommendations were made that are universally applicable to resort-
type, multi-unit facilities. 

As in Kekaha, the COE surveyed stillwater elevations and debris lines 
throughout the Poipu Beach area. Preliminary results indicated highly variable, 
but severe, coastal flooding, ranging from approximately 13.5 to over 20 feet 
mllw. When combined with breaking waves of significant height, the coastal 
flooding generated by Hurricane lniki along Poipu Beach was a very serious 
hazard. Areas such as Poipu Beach that have been identified by FEMA as Coastal 
High Hazard Areas require prudent design considerations, including both siting 
of buildings on lots and specific design and construction guidelines. 

Coastal flooding in the section from Spouting Horn Park to Poipu Beach Park was 
severe and widespread, resulting in substantial damage to an estimated 60 or 
more single-family, detached residences (FIGURE 6). Several condominiums and 
hotels fronting the ocean also sustained significant flood damage to their 
lowest (ground level) units. Table 1 provides a preliminary inventory of damaged 
buildings for particular segments. The damage was caused by direct wave impact 
on buildings that were constructed without adequate consideration of the 
potential flood hazard. Additional damage was caused by debris impact. This 
debris included lava rocks, trees, detached pieces of buildings, and in some 
cases entire buildings that rammed adjacent structures (FIGURE 7). 

[Begin figure]
FIGURE 6 is a pie chart showing the results of preliminary field inventory of 
damaged residential buildings - Poipu Beach Park to Spouting Horn Park. 
RESIDENCES WITH 90 -100% DAMAGE -31  
RESIDENCES WITH 70 -90% DAMAGE - 15
RESIDENCES WITH 50 -70% DAMAGE - 17
RESIDENCES WITH LESS THAN 50% DAMAGE – 23
[End figure]

[Begin table]
TABLE 1 
RESIDENTIAL BUILDINGS SUBSTANTIALLY DAMAGED* By FLOODING AT POIPU BEACH 
Spouting Horn Park to Lawai-Amio Intersection 8 
Lawai-Amio Intersection to the Kuhio Shores 17 
Hoona Road Poipu Beach 18 
Poipu Beach to Pee Road 20 
Total 63 

* Damage estimates are approximations based on field observations. Precise 
damage valuations ' will require detailed estimates and appraisals. 

NOTE: Use of commercial names as notable landmarks is for locational purposes 
only. 
[End table]

[Begin figure]
FIGURE 7. Waterborne debris resulted in significant damage to non- elevated 
buildings along Poipu Beach. 
[End figure]

Flood damage at Poipu Beach was the result of one primary and three secondary 
factors: 

1. Lack of Elevation. Almost without exception, the lowest floors of buildings 
were constructed directly on the ground (FIGURE 8). Because the lowest 
horizontal structural members of buildings were not elevated to or above 
predicted flood heights, all (or large sections) of the buildings' walls were 
directly impacted by significant hydrodynamic and debris impact forces. 

Three types of failure modes were observed: 

- Where buildings rested on piers with very shallow poured footings and 
precast concrete foundations ("tofu" blocks) with insufficient or no (i.e., 
gravity) connections between support posts and foundation, they were 
literally floated off their foundations by buoyant forces as the waters rose 
(FIGURE 9). In some instances, these "floaters" were carried considerable 
distance inland. In others, they were pinned against trees or other stable 
objects and then destroyed by waves (FIGURE 10). There was clear evidence that 
in some instances these buoyed buildings crashed into other buildings, causing 
further damage (FIGURE 11).

[Begin figures]
FIGURE 8. Typical example of residential construction along Poipu Beach that was 
destroyed because it was not elevated above the flood hazard. 

FIGURE 9. Non-elevated house at Poipu Beach that floated off its foundation and 
was transported well inland. 
20 BUILDING PERFORMANCE ASSESSMENT TEAM REPORT 
[End figures]

- In most instances where the bottom sill plate was fastened to the grade slab, 
the building was partially or entirely dislodged from its foundation. Either the 
wooden sill plate failed at the anchor bolts (FIGURE 12) or the vertical members 
(studs) were dislodged from the sill plate (FIGURE 13). 

- Where the vertical members were not tom from the foundation, the walls were 
dislocated and the building's interior destroyed (FIGURE 14). 

[Begin figures]
FIGURE 10. Non-elevated house at Poipu Beach that floated off its 
foundation was pinned against another house and destroyed by waves. 

FIGURE 11. Non-elevated building at Poipu Beach that rammed and increased damage 
to an adjacent building. 

FIGURE 12. Non-elevated building at Poipu Beach destroyed by coastal flooding. 
Sill plate ripped from anchor bolts. 

FIGURE 13. Non-elevated building at P oipu Beach destroyed by coastal flooding. 
Vertical members ripped from sill plate. 

FIGURE 14. Interior of non-elevated building at Poipu Beach destroyed by coastal 
flooding. 
[End figures]

The exact failure mode is inconsequential since the overriding factor was lack 
of elevation above the designated and/or actual flood level. Without elevating 
buildings to or above flood heights to allow for the free passage of velocity 
water underneath, it is essentially impossible (or at the least not cost-
effective) to construct a building to withstand such forces. 

2. Improperly Embedded or Constructed Foundations. Numerous instances of 
undermined foundations in the Poipu Beach area were observed (FIGURE 15). 
Coastal flooding is typically associated with significant erosion and localized 
or conical scour around posts and other embedded foundation elements. A critical 
building design consideration is the embedment of the foundation relative to the 
erosion depth caused by such storms. If piers, posts, or columns are not 
embedded deep into unconsolidated sediment or securely connected to natural lava 
rock deposits, the foundation of even a properly elevated building can be 
undermined and the building destroyed (FIGURE 16). 

[Begin figures]
FIGURE 15. Foundation at Poipu Beach undermined by erosion. 

FIGURE 16. Undermining of shallow pier foundation at Poipu Beach due to lack of 
sufficient embedment below erosion depth. 
[End figures]

3. Lava Rock and Other Debris. From detailed field observations, it can be 
concluded that low (2- to 4-foot-high) landscaping lava rock walls offer little 
flood protection even when they are not destroyed. In many cases, lava rock 
walls failed in part or completely (FIGURE 17), generating a significant amount 
of large projectiles which caused additional damage to buildings landward and/or 
to neighboring buildings (FIGURE 18). Design professionals should reconsider the 
suitability of oceanfront lava rock walls seaward of buildings. Other debris 
also acted to batter buildings. This debris was generated primarily from 
buildings destroyed during the storm. Building debris can be significantly 
reduced if new construction is built with consideration of the flood hazard 
design criteria. 

[Begin figures]
FIGURE 17. Breakup of grouted lava rock walls at Poipu Beach generated 
waterborne projectiles. 

FIGURE 18. Waterborne lava rock projectiles at Poipu Beach increased damage to 
non-elevated buildings. 
 [End figures]

4. Distance from Shoreline. Buildings sited extremely close to the shoreline 
(within 10 to 40 feet) in many cases were completely destroyed (entirely 
dislodged from foundations). In comparison, buildings placed on the back portion 
of ocean-front lots and buildings on the second inland tier of lots suffered 
less damage. While relative location of a building to the shoreline is 
important, damage at Poipu Beach is related much more to the lack of elevation. 

The Poipu area includes hotels and condominiums with ground-level units. The 
team observed numerous instances in which hotel and condominium ground-level 
units had been rendered uninhabitable by wave impact. While ground-level units 
may be attractive from a resort and recreational perspective, they represent 
imprudent design and construction practices in Coastal High Hazard Areas. 
Construction of new and repair of substantially damaged condominiums and hotels 
must be done in compliance with floodplain management provisions in the Kauai 
County Zoning Ordinance. Resort management firms and insurance companies would 
significantly reduce their financial liabilities associated with damages and 
business interruptions resulting from future disasters by designing new and 
substantially improved construction in such a way that the floors of the lowest 
units are above flood levels and the areas underneath are kept free of 
obstructions to allow uninterrupted flow of high-velocity floodwaters and waves. 
Such construction practices have become commonplace throughout the mainland 
United States without compromising architectural standards or revenue 
considerations. 

2.3 CONCLUSIONS 

Where foundations of multi-story or split-level residential buildings were not 
undermined, the lower areas were significantly damaged, but the upper levels 
suffered less damage (FIGURE 19). For condominiums and hotels with engineered 
foundations and shear-wall construction, the architectural components of the 
ground-level units were completely gutted by wave forces (FIGURE 20), while 
second-story units experienced no flood damage. These examples further attest to 
the prudence of elevating buildings above the flood hazard. 
[Begin figures]
FIGURE 19. Non-elevated buildings at Poipu Beach. Lower area gutted; upper area 
suffered much less flood damage. Note transported lava rock debris, which can 
cause additional damage. 

FIGURE 20. Typical non-elevated condominium or hotel. Interiors of lower 
units destroyed; upper units suffered considerably less flood damage. Elevating 
a building's lowest floor and keeping lower areas clear to allow passage of 
velocity water can significantly reduce future flood damage. 
[End figures]

Poipu Beach, Kekaha and other areas of the County are subject to coastal 
flooding from hurricanes and tsunamis. In these areas, future damage can be 
significantly reduced by elevating the lowest horizontal structural member 
(i.e., the floor system) of buildings above predicted or anticipated flood 
levels. For designing new construction and repairing substantially damaged 
buildings, flood levels indicated on the Kauai County FIRM or produced by 
Hurricane Iniki (whichever are greater) should be used. Alternatively, Kauai 
County could consider adding a freeboard of approximately 3 feet on the flood 
elevation requirements designated along the south shore on the existing FIRM. 

In addition, the horizontal structural members supporting the lowest floor must 
bear on piles or columns to allow velocity waters to freely pass beneath the 
lowest floor of buildings. These foundations must also be affixed securely to 
resistant lava rock or be sufficiently embedded in unconsolidated sediment to 
withstand the erosion and localized scour caused by hurricane-induced waves. 
While foundation types and construction materials may differ for condominiums or 
hotels, the basic minimum elevation and foundation-embedment and/or anchoring 
principles apply. Proper implementation of these basic design standards, which 
are required under the NFIP, will considerably reduce future hurricane and 
tsunami flood damages in Kauai County. 

For non-elevated buildings, a clear relationship was observed between severity 
of flood damage sustained and distance from the shoreline. Thus, in conjunction 
with NFIP floodplain construction standards, damage to future construction in 
areas subject to coastal flooding could be reduced by locating buildings as far 
back from the shoreline as is feasible or acceptable. 

In many areas along Poipu Beach, the flood elevations and inland flood 
penetration produced by Hurricane Iniki surpassed those shown on the existing 
FIRM. The FIRM is based on a hybrid system that considers tOO-year tsunamis and 
wave runup recorded from Hurricane Iwa (1982).. In light of the magnitude of the 
flood elevations associated with Hurricane Iniki, FEMA should incorporate those 
elevations into a reevaluation of the flood hazard along the south shore of 
Kauai County and other counties in Hawaii and, if warranted, revise the FIRMs 
accordingly. 

3.0 OBSERVATIONS OF WIND DAMAGE AND SUCCESSFUL BUILDING PERFORMANCE UNDER WIND 
LOADING CONDITIONS 

3.1 FIELD SITES 

The team surveyed the island in a comprehensive manner for wind damage. Field 
sites included the following: 

- Princeville, for examples of contemporary (post.-1974) single-family and 
multi-unit, heavy- and light-timber, one- and two-story wood-frame construction 
in exposed areas subject to amplified wind speeds and not subject to flood 
damage. 

- Hanalei, for examples of both contemporary and older, traditional Hawaiian 
construction, which coincidently is located in a flood hazard area but suffered 
no flooding of significance. 

- Anahola, Wailua, Kapaa, and Lihue, for examples of a mixture of contemporary, 
light wood-frame construction, traditional homes, and commercial establishments. 

- Nawiliwili Harbor and other sites, for examples of commercial/industrial 
metal-frame warehouse construction. 

- Kekaha and Hanapepe and vicinity, for examples of both older construction and 
a new subdivision containing light wood-frame construction. 

3.2 OBSERVATIONS OF BUILDING PERFORMANCE UNDER WIND LOADING 

Observations of the impact of wind forces included various building types 
damaged at the above sites, as well as buildings that incurred little or no 
damage. The discussion of observations presented in the following subsections 
addresses the following: 

- Modes of failure and examples of inappropriately designed and constructed 
structural systems. 

- Modes of successful performance and examples of properly designed and 
constructed structural and roofmg systems, as well as noteworthy architectural 
detailing and construction craftsmanship. 

- Roof sheathing (e.g., plywood) and roof cladding (e.g., shingles) and their 
methods of attachment. 

- Architectural features, such as the amount, type, installation, and protection 
of glazing (windows and glass doors), and roofing 
configurations, such as large overhanging, steep, or offset roof lines. 

- Windbome debris and its role in causing damage. .Quality of construction and 
workmanship. 

- Deterioration (e.g., rotting, rusting) and its role in contributing to damage. 

3.3 DIAGNOSTIC MODES OF STRUCTURAL FAILURE 

The most pervasive type of failure to primary structural systems was caused by 
uplift forces on roof systems that were incompletely or inadequately connected 
to walls. 

Primary structural systems are those that frame the building to resist applied 
forces. In residential applications, these systems are made up almost entirely 
of the exterior and interior loadbearing and non-loadbearing walls, the roof and 
floor systems, and the foundation. The integrity of the overall structure 
depends not only on the strength and deflection performance of these components, 
but also on adequate designs of the connections between the components. 

In the majority of cases on Kauai, when properly engineered and constructed 
residential units were built to define the continuous load transfer path, their 
performance under the storm conditions was significantly improved. Where there 
was construction that evidenced a breakdown in the load transfer path, damage 
extent ranged from considerable to total, depending on the configuration, type 
of construction involved, and the exposure to both flood and wind loads. 

One- and two-story wood light-frame buildings were the most severely damaged 
type of construction. Building failure was primarily a result of 1) wind 
overload to roof systems caused by uplift forces, and 2) wall failure from 
direct wind pressure on interior and exterior walls which lost top support once 
all or part of the roof was lost. Simply stated, the roof system is a key 
component that provides stability by supporting the tops of exterior and 
interior loadbearing walls and exterior non-loadbearing walls of the building. 
Geometric stability of the wall system is generally dependent on the roof as a 
top lateral support. Buildings whose walls did not fail even after the loss of 
the roof may have been geometrically stabilized by the interior partition walls, 
such as in the smaller residences with numerous interior walls. Once the roof is 
partially or fully lost, the ability of the walls to withstand wind pressure is 
greatly diminished (FIGURE 21). 

[Begin figure]
FIGURE 21. Once the roof system is compromised, the ability of the wood- frame 
exterior walls to withstand external wind pressure is greatly diminished. 
[End figure]

The roof framing systems observed were typically composed of prefabricated 
trusses or job-site-assembled timber rafters or trusses. Four key failure points 
in the loss of these roof systems were consistently observed: 

- Inadequate design. 
.Reliance on simplistic and inadequate nailing procedures to construct the roof 
structures (FIGURES 22, 23, and 24). 

[Begin figures]
FIGURE 22. Roof rafter construction with simple nailing or toenailing failed 
under uplift forces. Note two nails used to connect each rafter to hip beam. 

FIGURE 23. Toenailing of ridge beam to gable-end support. Rooffailure from 
uplift. 

FIGURE 24. Toenailing of rafter to ridge beam. Rooffailurefrom uplift. 
[End figures]

- Reliance on simplistic nailing procedures to connect the roof structure to the 
wall system (FIGURE 25). 

[Begin figure]
FIGURE 25. Toenailing of roof rafters to wall system. At this critical 
connection, toenailing does not provide the load transfer path necessary to 
withstand uplift forces. 
[End figure]

- Improperly sized, designed, or connected metal straps, fasteners, or hangers 
used to construct roof systems and/or connect roof and wall systems (FIGURE 26). 

[Begin figure]
FIGURE 26. Example of improperly sized and placed metal fastener, which led to 
roof failure from wind uplift forces. 
[End figure]

The simplistic nailing procedures (generally toenailing) used to construct roof 
systems such as rafter tie-ins to the ridge beam or rafter attachments at stud 
wall sides or comers were not adequate to withstand significant wind loading. 
This is especially true in exposed areas along coastlines or other areas 
subjected to terrain-amplification of wind speed and subsequent forces. Simple 
toenailing of rafters and wood trusses to stud walls was a regularly observed 
failure point. Such toenailing did not provide the complete load path to 
distribute the uplift and lateral loads from the roof to the walls and therefore 
should be eliminated as an accepted practice. 

Shortcomings in design and construction practices such as toenailing were 
technically allowed due to reliance on implicit provisions in the 1985 UBC. 
Appendix Section 2518 of the 1991 UBC is very explicit in its requirements and 
contains graphical presentations not contained in older versions of the Code. 
For new and repair construction, much of the structural damage observed due to 
wind forces can be prevented if provisions in Appendix Section 2518 are 
correctly implemented. 

Metal straps, anchors, or mechanical fasteners used on buildings that suffered 
roof and other structural damage were typically not sized, designed, or attached 
properly or lacked the proper coating (hot-dipped galvanizing) necessary for 
highly corrosive marine environments. Corrosion results in a loss of section and 
a loss of material strength, and the clips, anchors, and fasteners fail at loads 
below the design load. The use of metal connectors or hurricane clips in and of 
itself does not necessarily result in successful building performance. 

In one noteworthy failure that characterizes this problem, light-gage metal 
straps were nailed to the top of a vertical post, bent upward in an L-shape, and 
nailed to one side of a horizontal roof beam (FIGURE 27). Instead, a heavy-gage 
metal strap used continuously in an over-the-top or collar fashion and securely 
nailed on either side of the vertical post would have been the proper connection 
and would have provided an acceptable complete load path between the roof and 
the wall system. Graphic examples of proper load path connectors such as this 
are contained in Appendix Section 2518 of the 1991 UBC. 

[Begin figure]
FIGURE 27. Undersized and improperly attached metal fasteners led to roof damage 
from uplift forces. 
[End figure]

A second type of roof system observed was prefabricated (factory-made) light- 
wood trusses with plywood sheathing. Trusses themselves performed relatively 
well under wind loads (FIGURE 28). However, because connected trusses and 
sheathing formed the horizontal diaphragm of the building system, truss systems 
tended to become unstable and failed to varying degrees when the sheathing was 
lost (FIGURE 29). This amplified failures due to the inadequate load transfer 
mechanism between truss and wall systems, as previously described (FIGURE 30). 

[Begin figures]
FIGURE 28. Individual prefabricated wood roof trusses performed relatively well. 
BUILDING PERFORMANCE ASSESSMENT TEAM REPORT 39 

FIGURE 29. Gable-end roof failure due to loss of roof sheathing and lack of 
gable bracing. 

FIGURE 30. Improper connection (toenailing) between roof trusses and wall 
systems. When roof sheathing was blown off by wind, unbridged trusses failed, as 
did the exterior wall. 
[End figures]

Gabled roof structures were invariably more failure-prone (FIGURE 31). Hip roofs 
(FIGURE 32) generally performed better than gabled-end roofs, clearstory roofs 
(offset roof peak), and other steeply pitched roof systems. The geometric 
discontinuity in these roof lines made the roofs susceptible to high localized 
wind-induced external pressure on eaves and soffits (FIGURE 33). 

FIGURE 31. Gable-end roof designs tended to be more failure-prone. 
BUILDING PERFORMANCE ASSESSMENT TEAM REPORT 41 

FIGURE 32. Low-pitched hip roofs are aerodynamically superior and generally 
performed better than steeply pitched gable-end roofs. 

FIGURE 33. Offset roof peak provides geometric discontinuity and results in 
greater localized wind-induced pressure, which can lead to roof and then wall 
failure. 
[End figures]

Roof overhangs or soffits 3.0 feet long or less, with adequate venting, suffered 
comparatively less damage from wind forces. Overhangs exceeding 3.0 feet in many 
instances failed to resist the uplift forces and were the source of progressive 
roof structure failure (FIGURE 34). Much of this failure was due to inadequate 
installation, lack of proper engineered enclosure of extended soffits, lack of 
tie-back from rafters to wall, and improper sheathing and venting. 

[Begin figure]
FIGURE 34. Excessive roof overhang and poor connections in many instances led to 
roof failure. 
[End figure]

In summary, incomplete design for load transfer (either improper roof 
construction or improper connection between the roof and wall systems) was found 
to be the most pervasive cause of structural failure of buildings due to wind 
loads. 

3.4 DIAGNOSTIC MODES OF SUCCESSFUL STRUCTURAL PERFORMANCE 

Noteworthy examples of properly engineered and constructed buildings were 
observed in Kauai County, both tract development houses and individual custom- 
built houses. Almost without exception, successful performance resulted from 
adequately designed and clearly defined continuous load transfer paths. Where 
connections, such as hurricane clips and metal straps, were correctly applied, 
buildings performed relatively well (FIGURE 35). 

[Begin figure]
FIGURE 35. Example of very successful heavy-gauge metal fastener connecting roof 
and wall systems. Note the over the top application and the number and size of 
lag bolts used for attachment. 
[End figure]

Examples of proper building design and construction were noted in two new 
subdivision developments in Kauai County. Both contained modestly sized, single-
story, light wood-frame construction. 

The following key design and construction factors led, at least in part, to 
successful performance of homes at these sites: 

- Creation of a continuous load transfer path through the use of proper 
connections between the roof and the wall, and between the walls and the 
foundation (FIGURE 36). 

[Begin figure]
FIGURE 36. Wood splice or strap provides a secure connection between wall and 
roof systems. Bolted metal anchor provides secure connection between vertical 
member and foundation. This is a fine example of a continuous load path. 
[End figure]

- Use of roof designs that are more aerodynamically stable. Both 
subdivisions were characterized by hip roofs with low angles and modest 
overhangs. 

- Proper attachment of roof cladding to roof sheathing. Properly nailed common 
fiberglass composition shingles were used and performed adequately. 

- Attention to construction details and sensible workmanship. Examples included 
the use of simple procedures to reduce susceptibility to termite damage (FIGURE 
37), diagonal bridging between the vertical supporting members near the 
foundation and the lowest horizontal structural member of the floor system, and 
roof ventilation, which apparently relieved internal pressures. 

[Begin figure]
FIGURE 37. Sensitive craftsmanship and attention to detail: Vertical 
preservative-treated posts 1/4 inch off ground to reduce probability of termite 
infestation and decay. 
[End figure]

These examples of properly designed load transfer paths and successful building 
performance in Kauai County during Hurricane lniki provide a valuable tool for 
education and training on proper design and construction methods. 

3.5 ROOF SHEATHING 

LOSS of roof sheathing (e.g., plywood) was a consistently observed failure mode. 
The primary cause of sheathing loss was the lack of adequate nailing of the 
sheathing to the structural underpinnings of the roof system (e.g., rafters, 
trusses, and purlins) (FIGURES 38-40). Frequently observed evidence of 
inadequate attachment including excessive space between staples or nails; lack 
of staples or nails where sheathing rested on rafters, trusses, or purlins; and 
failure of staples or nails to strike rafters, trusses, or purlins. In addition, 
excessive corrosion of inadequately protected nails and staples was observed. 
Where inadequate nailing or excessive corrosion occurred, high winds were often 
able to peel the sheathing from the roof structure. 

[Begin figures]
FIGURE 38. Improper attachment of sheathing to purlins. Note wide spacing, 
shallow penetration, misalignment, and corrosion of staples. 
BUILDING PERFORMANCE ASSESSMENT TEAM REPORT 47 

FIGURE 39. Improper nailing design and schedule for purlin-to-rafter attachment. 
Note infrequency of nails for large surface area. Nowhere is the plywood 
sheathing directly nailed to the rafter system. 

FIGURE 40. Loss of roof sheathing due to improper nailing design and schedule. 
48 BUILDING PERFORMANCE ASSESSMENT TEAM REPORT 
[End figures]

Once sheathing was lost, damage was increased by rainwater. Stripped sheathing 
was also a source of airborne projectiles which caused additional damage to 
adjacent buildings. Sheathing loss was particularly troublesome because 
sheathing composed a significant part of the building envelope. Sheathing loss 
often led to progressive roof structure failure. This in turn led to a loss of 
support for the tops of both interior and exterior walls. In many cases, this 
led to major structural damage and even total loss. 

Loss of sheathing was especially critical where roof structures (rafter or truss 
systems) were engineered. In these instances, the roof structure relied on the 
plywood to provide rigidity to the roof diaphragm. Once the sheathing was peeled 
from the purlins or trusses, the roof structure became unstable and highly 
susceptible to damage (FIGURE 41). 

[Begin figure]
FIGURE 41. Total roof failure due to loss of sheathing. 
[End figures]

Adequate roof rafter connections and use of truss bridging, proper roof system- 
wide lateral bracing, adequate cross-bracing at gable end trusses, and 
stiffening of the gable ends were observed to have provided additional 
structural roof support and supplemented the sheathing diaphragm for structural 
support. 

Corrugated metal roofing is the predominant type of roof covering in Kauai 
County. In most cases it is used on small 800- to 1200-square-foot rectangular 
wood-frame "single wall" structures that typify the traditional architecture 
style in Hawaii. Failure of this roofing material occurred at points of 
attachment to underlying rafter systems (FIGURE 42). Such damage was attributed 
to improper fastening procedures and, in some instances, to rusting of metal 
panels at nailing locations, or to significant corrosion of the nails. 

[Begin figure]
FIGURE 42. Failure of corrugated metal roof at attachment points. These small, 
geometrically stable, "single wall," rectangular structures with numerous 
interior partition walls often remained structurally intact after loss of metal 
coverings. 
[End figures]

Usually, however, loss of corrugated metal roofs did not lead to further 
structural failure of buildings because 1) the metal sheets were simply 
coverings and do not serve to act as a stiffening for the roof diaphragm to 
provide structural stability to the walls and 2) the buildings on which these 
roofs are usually found are inherently stable as a result of their small plan 
size, rectangular shape, and numerous interior partition walls. Thus, loss of 
corrugated metal roofs, with the exception allowing some internal wind pressure, 
did not significantly decrease the structural integrity of these traditional-
style buildings. 

Loss of corrugated metal roofing was nonetheless a significant problem because 
of the resulting rainwater damage and the generation of windbome projectiles 
(FIGURE 43). Thus, considerable effort should be given to teaching building 
contractors, and especially homeowners, the proper fastening of corrugated metal 
roofing to the underlying rafters and purlins. 

[Begin figure]
FIGURE 43. Metal roof loss generates large airborne projectiles, which often 
cause additional damage. 
[End figure]

3.6 ROOF CLADDING 

Damage to roof covering or cladding such as extruded concrete and clay tiles, 
wood shakes, fiberglass composition shingles, and underlayment material was 
extensive at most field sites. While many structures escaped very costly 
structural frame damage, most structures suffered some degree of roofing damage. 
Damage to roof cladding permitted further damage to building interiors from 
high-velocity winds and rain, particularly since the common practice is to 
support concrete tile and wood shake roofing on spaced wood strips rather than 
complete roof sheathing. 

Close observation revealed that attachment procedures (stapling or nailing) for 
cladding types were deficient at many locations (FIGURE 44). Rarely was material 
failure caused solely by wind pressure. It was observed that less damage 
occurred to roofs where either staples or nails were sized and installed to 
generally accepted standards of construction practice. In some instances, 
individual tiles were observed that had not been nailed (FIGURE 45). 

[Begin figures]
FIGURE 44. Loss of roof cladding due to failure at attachment points. Notice 
that many staple crowns have corroded away on staples used to attach wood shake 
roofing to plywood roof sheathing. 

FIGURE 45. Heavy concrete tile attached at one point with undersized nail. It 
was also observed that neighboring tiles had not been nailed. 
[End figures]

Examples of properly attached roof cladding (both composition shingles and 
extruded tiles) with little or no damage were noted. Also notable was the better 
performance of cladding on flatter roofs. 

In general, there were failures observed of each of the attachment components 
that were integral to the proper installation of precast and molded tiles, 
either extruded concrete or clay. Underlayment failure, lack of attachment of 
each tile, and lack of mortar pads on ridge and steep-sloped sides were all 
observed. The use of mortar pads to provide improved adherence of roof tiles is 
not generally practiced in Kauai County. However, mortar has been shown to 
significantly improve adherence of the roof tiles. 

Roof cladding materials (tiles, shakes, or shingles) are designed to work 
together to form a secure attachment to underlayment and function as a 
continuous skin. Loss of one piece allows wind to effectively penetrate under 
and lift the next piece. This explains I the chain-reaction failure mode of 
shakes and tiles once debris impact or improper attachment allowed wind to 
remove the first few pieces of cladding (FIGURE 46). 

[Begin figure]
FIGURE 46. Roof cladding system composed of interdependent elements. Failure of 
one tile led to failure of adjacent tiles in a "chain reaction" effect. 
[End figure]

3.7 GLAZING AND TRANSPARENT OPENINGS 

Openings in exterior walls and roofs receive the various door, window, and 
venting systems necessary to complete, fully functioning architecture. The 
observed failures of the door and window "inserts" were typical of those that 
occur during high-wind events. These failures resulted in a breach of the 
building's envelope and allowed wind to directly enter the interior of the 
building. This resulted in an uncontrolled buildup of internal pressure that 
overloaded the building's structural components. While most glazing should be 
protected prior to significant storms, all other opening components should have 
performed acceptably without additional reinforcing. 

Failure of glazing (glasswork), such as windows, sliding track doors, and hinged 
doors, contributed to a significant percentage of the damage to buildings. 
Moreover, once glazing components and doors failed (FIGURE 47), the structural 
integrity of the building was compromised as previously described. Given an 
entrance path for uncontrolled wind forces, the interior components then become 
subject to wind and rainwater damage. More importantly, these openings, coupled 
with the penetration of wind, make buildings much more susceptible to extensive 
structural damage due to rapid buildup of internal wind pressures (FIGURE 48). 
The larger the area that is compromised, the greater the potential for damage. 
This process was a primary mode of failure of buildings in many areas, 
especially Princeville. 

Failure of exterior wall openings occurred in two ways: 1) shattering of glazing 
from projectile impact (FIGURE 47) and 2) implosion or explosion of glazing due 
to the combination of wind pressure and improper installation (FIGURE 49). 

[Begin figures]
FIGURE 47. Glazing broken by windborne debris or direct wind pressure. 

FIGURE 48. Loss of opening protection allows wind entry and increases internal 
exposure. 

FIGURE 49. Implosion of transparent shatter-resistant sliding door. Failure of 
door frame due to improper attachment to structural elements. 
[End figures]

Improper installation, for example, inappropriate attachment of window frames to 
the structural elements of the wall (FIGURE 50), and weak connections of 
expansive sliding doors (FIGURE 51), were consistently observed causes of the 
failure of glazing units. Where shatter-resistant material was used, failure was 
frequently observed where the material remained intact, but the unit, as a 
whole, was displaced inward by wind pressure (FIGURE 52) due to bowing and 
subsequent failure at the perimeter connections. 

[Begin figures]
FIGURE 50. Improper attachment of window unit. Note only one connection 
(nailing) point between unit and wall structure at the single shim. 

FIGURE 51. Improper connection of sliding glass door. Track attached with only 
three screws in vertical member. Sliding track on floor attached with caulk 
only. 

FIGURE 52. Gable-end window unit as a whole was displaced inward by wind 
pressure. Apparently, this allowed wind entry, increased interior pressure, and 
caused roof uplift. 
[End figures]

Open exposure of frangible (glass) windows and doors during high winds is 
problematic. Obviously, transparent components, including glazing, are 
fundamental and necessary architectural features of all residential structures. 
Yet, the use of glasswork over large, exposed surface areas without adequate 
protection significantly increases the potential for internal damage, and even 
seriously jeopardizes the performance of structures exposed to high wind loads 
and flying debris (FIGURE 53). Without the use of in-place working shutter 
systems (FIGURE 54), emergency protection such as securely fastened plywood, or 
non-frangible transparent materials, survival of glass work from flying debris 
becomes random chance. 

[Begin figures]
FIGURE 53. Extensive use of glazing on windward side can significantly 
compromise a building's envelope and lead to roof failure. 

FIGURE 54. In-place protective devices for glazing reduced the occurrence of 
building envelope failures. 
[End figures]

Furthermore, glasswork should be properly designed according to the same 
criteria used for the structure itself. Properly designed glasswork provides a 
factor of safety from failure due to direct wind pressures. 

3.8 WINDBORNE DEBRIS 

The primary sources of windborne debris, probably in decreasing order of 
prevalence, were improperly installed roof cladding (e.g., shingles, tiles, and 
shakes), structural failure of roof systems and thus wall systems, and 
improperly installed roof sheathing (e.g., plywood). Although windborne debris 
caused some damage to exterior siding from direct impact (FIGURE 55), by far its 
primary effect was in the shattering of unprotected glazing such as windows and 
glass doors. 

[Begin figure]
FIGURE 55. Windborne debris impact can puncture building and allow buildup of 
internal wind pressure. 
[End figure]

Thus in hurricanes such as Iniki, the modes of building failure are 
interconnected: Loss of roofing due to improper structural attachment or 
improper installation contributed to the number of windborne projectiles; this 
in turn significantly increased the potential for compromise of windows and 
doors and failure of neighboring buildings; this in turn further increased the 
number of windborne projectiles. 

As discussed in Section 4.0, the team observed that properly engineered and 
constructed architectural and structural components, attention to detail in 
attachment of roof cladding and sheathing, and proper design and protection of 
glazing components significantly reduced damages caused by windborne 
projectiles. 

3.9 DETERIORATION 

Weakening of structural components, sheathing, and cladding was caused by insect 
(termite) infestation and weatherization (rotting and rusting). This reduction 
in strength acted to increase damage. Several procedures could have been used to 
mitigate hurricane damage due to previously weakened wood and metal building 
material: 

- Use of proper building material, such as chemical-pressure-treated lumber, to 
reduce insect infestation, or corrosion-resistant fasteners to reduce attachment 
failures due to weakened fasteners. 

- Use of pre-painted wood and metal and periodic maintenance to reduce open- 
weather deterioration. 

- Application of sensible construction practices that reduce the probability of 
deterioration. For example, taking care that no part of a wood foundation system 
comes into contact with the soil (FIGURE 37). 

- Inspection and replacement of damaged elements. 

3.10 PRE-ENGINEERED STEEL WAREHOUSES 

Several pre-engineered steel warehouses at Nawiliwili Harbor, as well as other 
structured steel structures were analyzed. Warehouse failure typically included 
loss of light-gage metal sheet cladding (FIGURE 56) and, in several cases, 
failure of main structural members (FIGURE 57). Obvious points of failure 
included sill-to-concrete- foundation attachments (FIGURES 58 and 59) and 
rusting at attachment points. 

{Begin figures]
FIGURE 56. Steel warehouse failure commonly was due to loss of light- gauge 
metal sheet cladding. 

FIGURE 57. Steel warehouse failure was also due to failure of structural steel 
members. 

FIGURE 58. Failure of steel warehouse due to age and weatherization and 
insufficient anchorage to resist uplift. 

FIGURE 59. Steel warehouse, sill-to-concrete-foundation failure at anchoring 
points. 
{End figures]

Because these structures are generally pre-engineered by manufacturers, and 
referred to in performance language in the UBC, a detailed discussion of design 
considerations and failure modes is beyond the scope of this report. For further 
details refer to a report currently being prepared by the Structural Engineers 
Association of Hawaii. 

4.0 RECOMMENDATIONS 

There were noteworthy examples of buildings properly designed and constructed in 
compliance with current Codes that suffered little to no damage. However, there 
was also overwhelming field evidence to suggest the existence of certain 
deficiencies in past design and construction practices 'in Kauai County 
permitted under older versions of the Code. Much was learned from these 
deficiencies and associated building failures. Likewise, much was learned from 
some fine examples of properly designed and constructed buildings that suffered 
little to no damage. In the wake of Hurricane Iniki, during repair/ retrofit 
activities and new construction in Kauai County, it is important that lessons 
learned be applied in a positive, forward-looking manner. 

Therefore, the following recommendations are offered by the Building Performance 
Assessment Team. Consideration of these recommendations should be viewed as a 
shared responsibility, with leadership provided by Kauai County and assistance 
provided by Federal and State Governments and the private sector. Adoption of 
these recommendations, whether in part or in full, will require certain changes 
in administrative practices by the Kauai County government; others will require 
changes in the way that structures are designed and constructed by people in the 
building industry. Many of the recommendations can be accomplished through basic 
training and education with minimal increase in construction costs. 

4.1 FLOODPLAIN MANAGEMENT AND FLOOD DAMAGE 

- The single most important mitigating action to reduce future flood 
damages would be to properly administer NFIP requirements for new construction 
and the repair of buildings substantially damaged by 
Hurricane Iniki. These requirements are presently contained in the 
Floodplain Management provisions of the Kauai County Zoning Ordinance. 

- In accordance with NFIP requirements and the Kauai County Zoning Ordinance, 
all new construction and repair of substantially damaged 
buildings in Coastal High Hazard Areas along Poipu Beach, Hanalei, and 
other areas (in addition to all riverine flood hazard areas designated on the 
FIRM) must be elevated above anticipated flood heights (FIGURE 60) and 
constructed with proper foundations (FIGURES 61-76). 

- For future construction in coastal flood hazard areas, special consideration 
should be given to the depth of structure foundations relative to the maximum 
potential depth of erosion that will be caused by flood waters. Piers, posts, 
and columns should be embedded deep into unconsolidated sediment or, 
preferably, socketed into the natural lava rock deposits so that the foundation 
will not be undermined. (FIGURES 60, 62-65, 68-73, 75, and 76). 

[Begin figures]
FIGURE 60. NFIP requirements for elevated foundations in V zones. NOTE: 
Providing freeboard by elevating V ZONE lowest structural member above base 
flood Lowest structural member at or elevation is recommended, where feasible. 

Figure 61. One method of support for piers is a reinforced concrete footing. 
Note: Providing freeboard by elevating lowest structural member above base flood 
elevation is recommended, where feasible.

Figure 62.Drilled pier foundation.

Figure 63.Reinforced concrete pier.

Figure 64.Reinforced concrete masonry pier.

Figure 65. Reinforced brick pier.

Figure 66. Posts are placed into pre-dug holes and may be anchored in a concrete 
pad at the bottom of the hole. Lateral bracing should be oriented parallel to 
anticipated flow path. Note: Providing freeboard by elevating lowest structural 
member above base flood elevation is recommended, where feasible.

Figure 67. Posts can also be anchored in concrete encasements. Note: Metal 
fasteners and other hardware should be galvanized to resist corrosion. Note: 
Providing freeboard by elevating lowest structural member above base flood 
elevation is recommended, where feasible

Figure 68.Post on concrete bearing pad. Soil depth below maximum potential depth 
of scour is adequate to withstand lateral and vertical loads during the base 
flood.

Figure 69. Post on concrete bearing pad. Where soil depth below maximum 
potential depth of scour is inadequate to withstand lateral and vertical loads 
during the base flood, bottom of concrete should be socketed into lava rock for 
increased load resistance.

Figure 70.Post in concrete backfill.

Figure 71.Post on earth bearing.

Figure 72.Spike anchorage of post.

Figure 73. Galvanized strap anchorage of post.

Figure 74. Pilings are mechanically driven into the ground, making them less 
susceptible to velocity flooding, scour, and pullout. Note Metal fasteners and 
other hardware should be galvanized to resist corrosion. Note: Providing 
freeboard by elevating lowest structural member above base flood elevation is 
recommended, where feasible.

Figure 75. The depth of pile embedment provides stability to resist lateral and 
vertical loads through passive earth pressures.

Figure 76. Post/pile foundation
[End figures]

- In conjunction with NFIP requirements, future construction in areas subject to 
coastal flooding should be located as far back from the shoreline as is feasible 
or acceptable. This is based on the observed relationship between the distance a 
building was located from the shoreline and flood damage. The greater the 
distance, the less the damage due to dissipation of wave energy over the 
intervening area. 

- FEMA and the State of Hawaii should provide technical assistance to Kauai 
County staff for administration of these NFIP requirements. 

- FEMA, in cooperation with the State of Hawaii, Kauai County, and the local 
building industry, should sponsor a series of workshops in Kauai on floodplain 
requirements and prudent construction techniques in these hazardous areas. Such 
training and education will increase the knowledge base and awareness of 
business and homeowners, construction trades people, Engineers/Architects, 
supervisors, plan reviewers, and inspectors. 

- The FIRM for Kauai County predicts flooding in coastal areas based on the 
threat of tsunamis. Along the south shore of Kauai, a hybrid system which also 
considers wave runup recorded from Hurricane Iwa (1982) is used to predict flood 
levels on the FIRM. However, in many areas along Poipu Beach, the flood 
elevations and penetration produced by Hurricane Iniki surpassed those 
designated on the FIRM. Therefore, in the short- term (1-3 years), Kauai County 
should consider adoption of a dual management approach for the design of 
floodplain construction in the Poipu Beach area. This pertains to new 
construction and the repair of substantially damaged buildings. The lowest 
floors of such buildings should be elevated to or above the flood elevations 
shown on the FIRM or those experienced during Hurricane Iniki, whichever are 
greater. 

4.2 WIND DAMAGE AND WOOD-FRAME CONSTRUCTION 

- The design and construction of properly engineered buildings, in compliance 
with the most current Code, which consider the continuous load transfer path 
from roof to foundation should be integrated at all levels and into all stages 
of the building process in Kauai County (FIGURES 77-80). 

[Begin figures]
Figure 77. Recommended wood-frame construction. Based on Appendix Section 2518, 
1991 Uniform Building Code; adopted October 1992. Note: Refer to Appendix 
Section 2518 for wall sheathing, nail size and spacing, and the building size 
and type for which these details may be useful.

Figure 78. Typical roof truss top chord bracing.

Figure 79. Detail A – Typical web bracing.

Figure 80. Detail B – Typical wood gable-wall bracing with nailed connections.

Figure 81. Typical hurricane strap to roof framing detail. Rafter or 
prefabricated roof truss.
[End figures]

- Hurricane clips and straps, as key elements, must be used to help ensure the 
integrity of a structure's load path. Emphasis should be placed on the proper 
sizing, design, installation, and protective coating of these and other metal 
fasteners (FIGURES 74 and 81). (As noted previously, use of hurricane clips does 
not, in and of itself, ensure successful building performance). 

- Emphasis should be placed on adhering to Code for nailing requirements in 
general, with special attention to roof and wall sheathing, top and bottom wall 
plates, and hurricane clips and metal fasteners. 

- Additional structural ties at the ceiling line should be provided between 
large exterior walls and interior walls for large residential units to maintain 
integrity in the event of the loss of roofing. 

- The design of more aerodynamic building shapes should be encouraged, where 
feasible. Substituting low-angled hip roofs for steep angled, gabled-end, and 
clearstory roofs, and other such designs would be particularly advantageous 
(FIGURES 82 and 83). 

[Begin figures]
FIGURE 82. Recommended hip roof framing. 

Figure 83. Hip roof framing connectors. Detail A, B, and C.
- Large roof overhangs should be reviewed closely. Uplift-resistant connections 
for large overhangs should be engineered. 

- Requirements for tiedown straps for widely spaced roof framing members and 
corresponding wall-to-foundation connections should be defined. 

- Conventional construction Code requirements appear to take into consideration 
lateral forces such as wind and seismic loading; however, special consideration 
must be given to construction in areas where wind speed is amplified or areas of 
great exposure due to extreme topography (FIGURES 84-87). 

- Adoption of the 1991 UBC Appendix Section 2518 should be permanent. Appendix 
Section 2518 addresses previous Code deficiencies which relied on implicit 
provisions in the 1985 UBC. Appendix Section 2518 is very explicit in its 
requirements and contains graphical representations not previously contained in 
older versions of the Code. 


[Begin figure]
FIGURE 84. General notes for Figures 85-87. 
General:
1. All work shall conform to the building code of the County of Kauai. 
2. There are many different types of construction and details for existing 
single-family dwellings. The information and drawings presented are for general 
informational purposes only to illustrate the concept of the complete load path 
to resist high winds. The drawings are not complete design details or drawings 
and shall not be used as such. The information and details provided shall not be 
used or relied upon for any specific application without independent 
professional examination and verification of their accuracy, suitability, and 
applicability. 
3. The details are based on the following types of construction: 
A. Repair work only (not new construction) 
B. Single-story, single-family dwelling, with floor-to-ceiling height of 
approximately 8 feet 
C. Regular-shaped buildings with floor area of approximately 1,200 square feet, 
constructed on stable ground 

Materials:
1. Lumber: Douglas Fir/Larch, preservative treated, S4S, No, Grade or better.
2. Unless noted otherwise, all nailing shall be galvanized common nails and 
shall conform to Table 25-0 of the 1985 Uniform Building Code.
3. Framing hardware: Galvanized and of adequate strength. 
4. Framing, finish, and trim shall be notched for hardware as required to 
provide snug fit at all joints, 
5. Trim and finish details are not shown on framing details and sections, 
[End figure]

[Begin figures]
FIGURE 85. Existing “single wall” on slab-on-grade.

FIGURE 86. Existing “single wall” on existing concrete masonry unit wall.

FIGURE 87. Existing “single wall” on new concrete masonry unit wall and footingl
[End figures]

4.3 GLAZING AND TRANSPARENT STRUCTURAL OPENINGS 

- In areas of greatest exposure to windborne projectiles, consideration should 
be given to the use of in-place shutters or emergency protection devices 
(FIGURES 88-91), increased use of shatter-resistant transparent material, a 
reduction in the use of glazing, and improved adherence to adequate attachment 
procedures. 

- The specifications for windows and glass doors should be stated such that the 
design criteria for wind loading are the same as those for the structure itself. 

[Begin figures]
FIGURE 88. Prefabricated storm shutters. 

FIGURE 89. Previously purchased plywood stored for use as openings protection 
during storm conditions.

FIGURE 90. Plywood used as openings protection installed. 

FIGURE 91. an illustration showing a typical installation of plywood openings 
protection for wood frame building.
[End figures]

- The adequacy of the engineering design and method of attachment of 
windows and sliding transparent doors of all types should be reviewed by 
manufacturers for applications in areas subject to wind exposure. Wind loads 
should be adequately transferred to the supporting structure. 

4.4 ROOFING 

- Recognized procedures for testing roofing for resistance to wind (across the 
surface of the roofing) need to be developed. 

- Roofing materials should be installed according to the latest manufacturer's 
recommendations (FIGURE 92). 

[Begin figure]
Figure 92 is an illustration showing tips for galvanized roofing. 
[End figure]

- Roofing suppliers, manufacturers and associations should educate specifiers 
and installers concerning the proper installation requirements and techniques. 

- A program of periodic roof cladding inspection during installation should be 
adopted where such a program would not be cost-prohibitive. 

4.5 BUILDING PERMITTING, PLAN REVIEW AND INSPECTION

- Consistency of quality construction workmanship should be encouraged. 
Properly engineered construction drawings that are more prescriptive and 
detailed should be provided, and the depth of construction inspection 
should be increased, especially for tracts of homes of repetitive design. 

- Kauai County should retain a person qualified in structures on staff to assist 
in examining the adequacy of construction plans. This in-house expertise will 
allow for greater in depth County review of design and construction inspection. 
Responsibilities should include a program of systematic wall and roof framing 
and roof sheathing inspections. 

- Permit drawings for construction should include details and a narrative 
statement that explains the building system's transfer of forces, especially 
between the roof and wall systems, and the wall system and foundation. These 
permit drawings should include a checklist which verifies that the necessary 
continuous load transfer path has been provided. 

- Implementation of UBC Section 306, Special Inspection, requirements for large 
multi-family, commercial, and resort projects should be considered. 


4.6 TRAINING AND EDUCATION 

-The State and Kauai County governments and the local building industry, in 
cooperation with FEMA, should sponsor a program of training and continuous 
education in Kauai on Code requirements and construction techniques. In addition 
to structural design, these programs should cover roof sheathing, proper 
attachment of roof cladding, prevention of wood and metal deterioration, and the 
design and prudent use of glazing and transparent structural openings. Such 
training and education will increase the knowledge and awareness of business and 
homeowners, construction tradespeople, Architects/Engineers, supervisors, plan 
reviewers, and inspectors. 

- Considerable effort should be given to teaching building contractors, and 
especially home owners, the proper attachment of corrugated metal roofs to the 
underlying rafters and purlins. 

- A program should be established to gain the fullest participation of the 
citizens of Kauai County in the building development process and to ensure their 
awareness of the need to maintain critical building components. 

- A program should be established to educate sub-professionals who prepare plans 
to comply with current Code provisions. Review of these plans by qualified 
professionals should be encouraged. 

4.7 REPAIR/RETROFIT OF PARTIALLY DAMAGED AND UNDAMAGED BUILDINGS 

- During the Hurricane Iniki rebuilding period, Kauai County should explore all 
available resources for expanding the pool of qualified building inspectors. 

- Although some buildings suffered irreparable damage, most buildings are 
repairable, and repairs should be carried out with attention to the 
recommendations made in this report. 

- Retrofitting of undamaged buildings should be strongly encouraged so that wind 
damages to buildings constructed under the previous Code are minimized. 


APPENDIX A 
BUILDING PERFORMANCE ASSESSMENT TEAM MEMBERS AND ADVISORS 

TEAM MEMBERS 
Todd Davison, Federal Emergency Management Agency, Federal Insurance 
Administration, Team Leader, Washington, D.C. 

Robert Durrin, Federal Emergency Management Agency, Region IX, Team Coordinator, 
San Francisco, CA 

Charles E. Bornman, Greenhome & O'Mara, Inc., Division Manager, Structures, 
P.E., Greenbelt, MD 

Melvin T. Nishihara, State of Hawaii, Office of Civil Defense, Hurricane Program 
Manager, Honolulu, HI 

Michael K.H. Yee, Michael K.H. Yee, Consulting Structural Engineer, P.E., 
Honolulu, HI 

Lee T. Takushi, SSFM Engineers, Inc., Structural Engineer, P.E., Honolulu, HI 

Peter N. Taylor, Peter Taylor, Inc., Structural Engineers, Lihue, Kauai, HI 

John Maroun, Senior Technical Director, DMJM, Honolulu, HI 

TECHNICAL AND POLICY ADVISORS 

Thomas O. Batey, Administrative Assistant, Office of the Mayor, County of Kauai, 
Lihue, Kauai, HI 

Domingo 'Don' Lutao, Kauai County Department of Public Works, Code Enforcement 
Coordinator, Lihue, Kauai, HI 

BUILDING PERFORMANCE ASSESSMENT TEAM REPORT 99 

Anne Schneider, Kauai County, Planning Department, Architect, Lihue, Kauai, HI 

John Eldridge, Federal Emergency Management Agency, Region IX, Chief, Flood 
Hazards Branch, San Francisco, CA 

Robert Schofield, Federal Emergency Management Agency, Hazard Mitigation Team, 
Region X, Seattle, W A 

Steven Yamamoto, U.S. Army Corps of Engineers, Civil Engineer, Pacific Ocean 
Division, Honolulu, HI 

Charles H. Fletcher, Department of Geology and Geophysics, Ph.D., Honolulu, HI 

Ron Agor, Architect, AlA, Lihue, Kauai, ill 

Paul D. Armstrong, International Conference of Building Officials, Staff 
Engineer, Whittier, CA 

Gary T. Yamamoto Barrett, Consulting Group, Civil and Structural Engineer, P.E., 
Honolulu, HI 

David Ayer, Architect, AlA, Division Manager, DMJM, Honolulu, HI