Rapid Screening of Buildings for Seismic Retrofit Assessment Murat Saatcioglu PhD,P.Eng. Professor and University Research Chair Department of Civil Engineering The University of Ottawa Ottawa, ON

Why Seismic Screening?  Seismic retrofitting may be very costly  Before a decision is made, seismic assessment is required.  Before undertaking a detailed seismic assessment, a rapid screening of buildings may be in order.  NRC developed “Manual for Screening of Buildings for Seismic Investigation”

Seismic Screening  NRC Screening Manual is dated It has been revised recently at the request of PWGSC to conform to NBCC 2005 Seismic Hazard  Seismic screening provides a simple tool to a community or authority to easily identify buildings that might pose a risk of life or injury, or severe curtailment of community services in the event of a damaging earthquake

Seismic Screening  Seismic screening is conducted by a simple inspection without the cost of a detailed analysis of every building in a given region  Buildings that receive high score and is thus identified to be potentially hazardous require further investigation  NBCC Appendix K recommends that buildings that have seismic resistance of 60% and lower relative to the current code requirement may be retrofitted

Seismic Screening  The 60% value is a trigger value and does not indicate that seismically deficient buildings should be retrofitted to have 60% capacity  Once the decision to retrofit is made, it is advisable to improve the building performance up to the current standards expected from new buildings  Cost and performance should be weighed against each other before a decision is made

Seismic Screening The following has to be evaluated:  Seismicity(A): The maximum earthquake motion expected for the location of the building (seismic zone).  Soil Conditions(B): Soft soils amplify earthquake motions and damage buildings.  Type of Structure(C): The type of lateral force resisting system (LFRS) is important to assess potential seismic damage.

Seismic Screening The following has to be evaluated (Cont’d):  Building Irregularities(D): This applies primarily to weaknesses in configuration like soft storeys and captive columns.  Non-Structural Hazards(F): Non-load- bearing components of the building, such as block partitions, may fall on people or interfere with rescue operation.

Seismic Screening The following has to be evaluated (Cont’d):  Design NBC: Buildings designed to recent building codes are less vulnerable than buildings designed to older versions of the code.  Building Importance(E): The consequences of failure are more severe for post-disaster buildings and critical facilities. Also, risk in densely populated buildings is higher.

Seismic Screening Form

Seismic Priority Index Structural Index (SI) = A*B*C*D*E Non-Structural Index (NSI) = B*E*F Seismic Priority Index (SPI) = SI + NSI The scores should be used for the purpose of ranking SI or NSI of 1.0 to 2.0 indicate full compliance with the code. SPI < 10 indicates low priority SPI = 10 – 20 indicates medium priority SPI > 20 indicates high priority SPI > 30 potentially hazardous

Thank You….. Questions or Comments?