IRCC Hamburger

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www.sgh.com © Simpson Gumpertz & Heger Inc. 1 Development of Performance-based Seismic Design Standards & Criteria Ronald O. Hamburger, SE, SECB Senior Principal Simpson Gumpertz & Heger

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next gen performance based design

Transcript of IRCC Hamburger

  • Development of Performance-based Seismic Design Standards & CriteriaRonald O. Hamburger, SE, SECBSenior PrincipalSimpson Gumpertz & Heger

  • Code Procedures2003

  • Building Codes Imply PerformanceAbility to resist frequent, minor earthquakes without damage Ability to resist infrequent, moderate earthquakes with limited structural and nonstructural damage Ability to resist worst earthquakes ever likely to occur without collapse or major life safety endangerment100 yrs500 yrs2,500 yrsPerformance is not guaranteed2003

  • Building Codes & Peformance WarrantiesIf a building is affected by an extreme event and performs poorly:There is an expectation of how the building should have performed but no implied warrantyThe only warranty is that the engineer complied with the standard of careFor most buildings, demonstration that a design was performed in accordance with the building code will provide adequate proof of conformance to the standard of care

  • Code Basis for Performance-based DesignSection 104-

    The provisions of this code are not intendedto prevent . . . or to prohibit any design ormethod of construction. . . provided that anysuch alternative has been approved.

    An alternative. . . design shall be approvedwhere the building official finds that theproposed design is satisfactory andcomplies with the intent of the provisions ofthis code.

  • First Generation Standards are AvailableASCE/SEI has standardized FEMA guideline documents on:: Seismic EvaluationPredict types of damage a building would experience in future events (based on FEMA178)RehabilitationProcedures to design building upgrades to achieve desired performance (based on FEMA 356)Though not directly recognized by the building codes, these standards are being used as the basis for Performance-based design of new buildings and seismic retrofitASCE-31ASCE-41

  • Selecting PerformancePresent Generation

  • Code-equivalent PerformanceFrequent event (varying between 50- and 100- year return periods)DBEMCE

  • Next Generation Standards are Presently Under DevelopmentATC-58 Project10 year program funded by FEMADevelop next-generation criteria applicable to design of new buildings and upgrade of existing buildingsNew performance definitionsPerformance expressed in terms of the probability of incurring:Direct economic loss (repair/replacement cost)Casualties (deaths & serious injuries)Downtime (loss of use)Direct consideration of uncertainty in ground shaking, structural response, damage and the consequences of damage

  • 2 Phase Project ExecutionPhase 1Development of a performance assessment methodology that can be used to predict the probability of incurring the various losses, as a function of specific design decisionsPresently 35% completePhase 2 Development of procedures for designing buildings for desired performanceEstablishment of performance provided by current prescriptive proceduresAssessment of adequacy of performanceDevelopment of improved prescriptive methods that will provide desired performance

  • Performance-based designA new approach

  • 2 Phase Project ExecutionPhase 2 Development of procedures for designing buildings for desired performanceEstablishment of performance provided by current prescriptive proceduresAssessment of adequacy of performanceDevelopment of guidance on selection of structural systems, strength, stiffness, etc. that is likely to be able to meet performance goalsDevelopment of improved prescriptive methods that will provide desired performance