Seismically Resilient Houses
Enhanced Uni-body and Low-Cost Isolation


Project Overview

Although traditionally constructed residential structures provide a high level of life safety during an earthquake, their vulnerability to damage can be very costly. After the 1994 Northridge Earthquake, it was estimated that $20 billion were issued in insurance payouts for damaged residences. In addition, over 60,000 people were displaced from their homes for a significant period of time. To reduce the damage seen by these structures, this project includes experimental and analytical resarch to demonstrate effective methods to decrease the risk of damage, therby increasing the resiliency of the home.

Researchers at Stanford University and California State University, Sacramento are investigating new cost-efficient design and construction methods to create (1) a low-cost isolation system that protects the structure from large earthquake forces and (2) a uni-body framing system with enhanced strength and stiffness through full integration of the structural and architecural building components into the lateral load resisting system.

These new design methodologies have been tested through an integrated research plan, including several experimental phases at a wide-variety of scales, and numerous computational simulations to further develop behavioral insights. Fastener tests and medium-scale (4 ft. x 4 ft.) wall tests were conducted at Stanford University to identify construction methods and materials that formed the basis of the uni-body design approach. These tests informed a suite of full-scale (8 ft. x 8 ft. and 16 ft. x 8 ft.) quasi-static wall tests at California State University at Sacramento and full-scale (16 ft. x 7 ft. x 8 ft.) room assembly tests at the NEES@Berkeley site. In addition, small- and medium-scale tests on a variety of high-friction sliding materials/surfaces were conducted at Stanford University towards the development of a low-cost base isolation system. The isolation system consists of flat or dish isolation interfaces of visco-elastic polymers and finished steel. These combinations take advantage of the enhanced strength and stiffness the uni-body system and allow for a higher friction force as compared to traditional isolation applications with low friction materials. Small- and large-scale tests of the isolation interface were conducted at Stanford University and NEES@Berkeley, respectively. High-fidelity simulation models were developed and calibrated using these tests results.


In the News
"Could this design make houses more earthquake resistant?" BBC News
"NEES Community Update - May 2015" NEEScomm
"Stanford engineers build, test earthquake-resistant house" Stanford|News
"Quake-Resistant House Passes Shake Tests With Flying Colors" Engineering News-Record

NBC4 (LA affiliate) News Report

Project capstone specimen


FULL-SCREEN


Enhanced Uni-body Design



Low-Cost Isolation System




Publications

Swensen, S.D., Acevedo, C., Jampole, E.A., Hopkins, A., Fell, B.V., Miranda, E.M., Deierlein, G.G. (2014). "Toward Damage Free Residential Houses Through UniBody Light-Frame Construction with Seismic Isolation," SEAOC Convention 2014, Indian Wells, CA, September 2014.

Swensen, S.D., Deierlein, G.G., Miranda, E.M., Fell, B.V., Acevedo, C., Jampole, E.A. (2014). "Finite element analysis of light-frame unibody residential structures," Proceedings of the 10th National Conference in Earthquake Engineering, Earthquake Engineering Research Institute, Anchorage, AK, 2014.

Jampole, E.A., Swensen, S.D., Fell, B.V., Miranda, E.M., Deierlein, G.G. (2014). "Dynamic testing of a low-cost sliding isolation system for light-frame residential structures," Proceedings of the 10th National Conference in Earthquake Engineering, Earthquake Engineering Research Institute, Anchorage, AK, 2014.


Theses and Technical Reports

Swensen, S.D. (2015). "Seismically enhanced light-framed residential structures." PhD Dissertation, Stanford University, Stanford, CA.

Hopkins, A., Fell, B. V., Deierlein, G.G. and Miranda, E.M. (2014). "Large-scale tests of seismically enhanced planar walls for residential construction." Blume Earthquake Engineering Center Technical Report #186, Stanford University, Stanford, CA.


Industry Advisory Committee

Kelly Cobeen (WJE)
Geoff Bomba, Rene Vignos, Ali Roufegarinejad, and Mason Walters (FORELL/ELSESSER)
John Osteraas (EXPONENT)
Steve Pryor (SIMPSON STRONG-TIE)
David Mar
Greg Luth (GREGORY P. LUTH & ASSOCIATES)
Reynoud Serrete (SANTA CLARA UNIVERSITY)


Project Research Team

Principal Investigators
Gregory Deierlein, Principal Investigator, Stanford University
Eduardo Miranda, Co-Principal Investigator, Stanford University
Benjamin Fell, Co-Principal Investigator, California State University, Sacramento

Graduate Research Assistants
Cristian Acevedo, Ph.D. Candidate, Stanford University
Ezra Jampole, Ph.D. Candidate, Stanford University
Scott Swensen, Ph.D. (graduated), Stanford University
Amy Hopkins, M.S. (graduated), California State University, Sacramento


Acknowledgments

This material is based upon work supported by the National Science Foundation (NSF) under CMMI-NEES Grant No. 1135029. Additional financial support was provided by NSF through student fellowships, an EERI Graduate Student Fellowship, and the Blume Earthquake Engineering Center at Stanford University. Donation of materials and supplies is greatly appreciated from Simpson Strong-Tie, PPG Industries, Alabama Metal Industries Corporation (AMICO), and Albion Engineering. Any opinions, findings, and conclusions or recommendations expressed in this material are those of the authors and do not necessarily reflect the views of the National Science Foundation or other sponsors.

The authors greatly appreciate the talented group of professional consultants on our Industry Advisory Committee listed previously. The authors further acknowledge the assistance of several undergraduate research students, K. deLaveaga, C. Fong, M. Hardy, R. Khan, C. McEniry, R. McNerney, and G. Oren, as well as the support of the staff at NEES@Berkeley and NEES@UCSD.

Finally, the authors are indebted to Ben Schmidt, who inspired, guided and supported the authors to pursue research to improve the seismic performance of residential house construction.