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Why are the values of Water Treatment Plant damage parameters used in the HAZUS software different from those presented in the Earthquake Model Technical Manual (Chapter 8)?

HAZUS-MH and its three maintenance releases include a version of damage parameter values for water treatment facilities updated from HAZUS99. The Earthquake Model Technical Manual in Chapter 8, however, still presents HAZUS99 values. The tables below are the updated versions of the Chapter 8 damage algorithms tables.

Table 8.3: Damage Algorithms for Small Water Treatment Plants (PWTS)

Peak Ground Acceleration

 

 Damage State Median (g) B
Plants with anchored subcomponents

slight/minor
moderate
extensive
complete

0.25
0.40
0.70
1.35

0.60
0.60
0.60
0.65
Plants with unanchored subcomponents

slight/minor
moderate
extensive
complete

0.15
0.30
0.60
1.25

0.60
0.60
0.60
0.65

Table 8.3: Damage Algorithms for Medium Water Treatment Plants (PWTM)

Peak Ground Acceleration

 

 Damage State Median (g) B
Plants with anchored subcomponents

slight/minor
moderate
extensive
complete

0.25
0.40
0.70
1.35

0.60
0.60
0.60
0.65
Plants with unanchored subcomponents

slight/minor
moderate
extensive
complete

0.15
0.30
0.60
1.25

0.60
0.60
0.60
0.65
 
Table 8.3: Damage Algorithms for Large Water Treatment Plants (PWTL)
 

Peak Ground Acceleration

 

 Damage State Median (g) B
Plants with anchored subcomponents

slight/minor
moderate
extensive
complete

0.25
0.40
0.70
1.35

0.60
0.60
0.60
0.65
Plants with unanchored subcomponents

slight/minor
moderate
extensive
complete

0.15
0.30
0.60
1.25

0.60
0.60
0.60
0.65
 
Also, for anchored and unanchored subcomponents in water treatment plants, the HAZUS-MH software selects damage functions for these conditions through a Boolean field applied to the following classification scheme:

PWTS = small water treatment plants
PWTM = medium water treatment plants
PWTL = large water treatment plants

However, the Earthquake Model Technical Manual still reflects the HAZUS99 approach in which facilities with anchored or unanchored subcomponents draw damage functions based on a different classification scheme as shown below.

HAZU99 Water Treatment Plant Classification

Classification

Description

PWT1

Small water treatment plants with anchored subcomponents

PWT2

Small water treatment plants with unanchored subcomponents

PWT3 

Medium water treatment plants with anchored subcomponents

PWT4

Medium water treatment plants with unanchored subcomponents

PWT5

Large water treatment plants with anchored subcomponents

PWT6

Large water treatment plants with unanchored subcomponents

Both the damage algorithm and classification tables in Chapter 8 of the Earthquake Model Technical Manual will be coordinated with the HAZUS-MH software in the next release.

Last Modified: Wednesday, 11-Aug-2010 14:34:10 EDT