Example Effects of NEES Research on Structural Design Practice

1. Example Effects of NEES Research on Structural Design Practice Bill Holmes Rutherford + Chekene San Francisco NEES Governance Board Workshop

2. Discussion • Building code change cycle is, at the least, 5 years. After research results are recognized, it takes a while to get into codes and longer to get into common practice. • Examples given here are not based on comprehensive review of every NEES project, but known examples of current input into codes and standards. • Some concrete examples suggested by SK Ghosh. • Some steel examples suggested by Jim Malley • Some wood example suggested by Kelly Cobeen NEES Governance Board Workshop

3. Overarching • Simulation (analysis) methods in practice in all materials are gradually improving due to NEES laboratory results of testing and researcher improvements to nonlinear modeling • Fragilities used in loss analyses—particularly the FEMA P58 methodolog--have been improved for several structural systems and nonstructural components. • Several projects contributed to development of concrete column performance database that significantly improved ASCE 41 in 2007. • Same database with improvements currently being used to develop practical evaluation of older concrete buildings to identify significant collapse risks. NEES Governance Board Workshop

4. Concrete • NEESR-GC: Mitigation of Collapse Risk in Vulnerable Concrete Buildings • Improved understanding of joint behavior in older concrete frames for use in evaluation • Significant risk awareness effect due to LA inventory of older concrete buildings. Probable future mitigation effect. • NEESR-CR: Assessment of Punching Shear Vulnerability of Slab-Column Connections • Presented to ACI 318; future provisions concerning headed stud reinforcement will be influenced. • NEESR-SG: Performance-Based Design of Squat Reinforced Concrete Shear Walls • results of these tests were used to establish a diaphragm design force reduction factor for cast-in-place reinforced concrete diaphragms. NEES Governance Board Workshop

5. Concrete • NEESR-SG: Seismic Behavior, Analysis and Design of Complex Wall Systems • The products of this research were a valuable resource to the ATC-94 projectstudying the 2010 Chile Earthquake. The ATC-94 project, in turn, had an influence on the revision of special shear wall design provisions for ACI 318-14. • NEESR: Seismic Performance of Conventional and Innovative Special Structural Walls; NEESR-SG: Seismic Behavior, Analysis and Design of Complex Wall Systems • This research has had an impact on the revision of special shear wall design provisions for ACI 318-14. • The NEES DSDM (Diaphragm Seismic Design Methodology) research carried out by Rob Fleischman et al. • Influenced several code changes in NEHRP Provisions • Research interacted with IT 06 of the PUC to make more applicable • Has large effect on diaphragm white paper to be published in NEHRP Provisions, 2014. NEES Governance Board Workshop

6. Steel • For older construction, the work on older braced frames that is ongoing at the Berkeley NEES site, in conjunction with the University of Washington, is making great advances in better understanding the response of these systems. • For present construction, the work by UC Davis researchers at Berkeley NEES will result in an improvement to the AISC 341-16 document. In addition, work at Berkeley and Minnesota as part of the braced frame project with U of Washington and NCREE in Taiwan has provided information that will cause changes to both AISC 341-16 and AISC 360-16. • Shaking table testing to collapse of a moment frame structure at SUNY-NEES demonstrated large displacement capacity, confirming that present design approaches are adequate for collapse response. • The next generation of systems that provide high performance including the ability to self-center are being studied at NEES-UIUC and NEES-Lehigh. These system will likely be widely used in the future, as demand by owners for performance beyond code minimum values increases. NEES Governance Board Workshop

7. Timber • Research contributed to understanding of behavior of soft story wood framed buildings, now being mitigated in several communities due to mandatory retrofit ordinances • Research resulted in development of new wood frame structures up to 6 stories tall NEES Governance Board Workshop

8. Miscellaneous • NEESR-SG: Seismic Performance Assessment and Retrofit of Non-Ductile RC Frames with Infill Walls • Used to update infill provisions of ASCE 41 • All projects related to Tsunami, but particularly, NEESR-SG: Development of Performance Based Tsunami Engineering • Provided input into the FEMA funded document on vertical evacuation structures. • Resulted in completely new chapter on Tsunami Loading in ASCE 7. • NEESR-GC: Simulation of the Seismic Performance of Nonstructural Systems • Contributed to development of fragilities in FEMA P-58 methodology • Provided insight into performance of suspended ceilings in large spaces—never tested before; will result in refinement of installation standards. • Dynamic testing of 5-story concrete building with nonstructural contents in San Diego resulted in several insights. • Immediately, change in ASCE 7 egress stair requirements are in ballot NEES Governance Board Workshop