Seismic Performance of Single-Family Wood-Frame Houses: Comparing Analytical and Industry Catastrophe Models (PEER-CEA Project), PEER Report 2020-24

This  report  is  one  of  a  series  of  reports  documenting  the  methods  and  findings  of  a  multi-year,  multi-disciplinary  project  coordinated  by  the  Pacific  Earthquake  Engineering  Research  Center  (PEER  and  funded  by  the  California  Earthquake  Authority  (CEA).  The  overall  project  is  titled  “Quantifying the Performance of Retrofit of Cripple Walls and Sill Anchorage in Single-Family Wood-Frame Buildings,” henceforth referred to as the “PEER–CEA Project.”

The  overall  objective  of  the  PEER–CEA  Project  is  to  provide  scientifically  based  information  (e.g.,  testing,  analysis,  and  resulting  loss  models)  that  measure  and  assess  the  effectiveness of seismic retrofit to reduce the risk of damage and associated losses (repair costs) of  wood-frame  houses  with  cripple  wall  and  sill  anchorage  deficiencies  as  well  as  retrofitted  conditions that address those deficiencies. Tasks that support and inform the loss-modeling effort are: (1) collecting and summarizing existing information and results of previous research on the performance   of   wood-frame   houses;   (2)   identifying   construction   features   to   characterize   alternative  variants  of  wood-frame  houses;  (3)  characterizing  earthquake  hazard  and  ground  motions  at  representative  sites  in  California;  (4)  developing  cyclic  loading  protocols  and  conducting  laboratory  tests  of  cripple  wall  panels,  wood-frame  wall  subassemblies,  and  sill  anchorages to measure and document their response (strength and stiffness) under cyclic loading; and (5) the computer modeling, simulations, and the development of loss models as informed by a workshop with claims adjustors.

This  report  is  a  product  of  Working  Group  (WG)  6:  Catastrophe  Modeler  Comparisons and  focuses  on  comparing  damage  functions  developed  by  the  PEER–CEA  Project  with  those  currently  contained  in  modeling  software  developed  by  the  three  largest  insurance  catastrophe  modelers:  RMS,  CoreLogic  and  AIR  Worldwide.  A  semi-blind  study  was  conducted  in  collaboration  with  the  modeling  companies  to  compare  damage  estimates  for  a  selection  of  the  Index Buildings developed in the PEER–CEA Project Study. The WG6 Project Team conducted several  meetings  with  these  modeling  companies  to  gather  feedback  on  the  structure  of  and  assumptions  made  by  the  PEER–CEA  Project.  The  comparative  results  are  evaluated  and  presented herein.