Western_Michigan_University_CCE

Less Logo

 

 

Current Projects

 

NEESR: Near Collapse Performance of Existing Reinforced Concrete Frame Buildings

 

Real-Time Hybrid Simulation with Online Model Updating

 

Completed Projects

 

NEESsoft: Seismic Risk Reduction for Soft-Story Woodframe Buildings

 

US-China Distributed Test

 

Cyclic Testing of two HGA10 connectors for CLT panels

 

Return to Projects Webpage

NEESsoft: Seismic Risk Reduction for Soft-Story Woodframe Buildings

 

NEESsoft

Project Duration: 7/2011~9/2014 Description: The vision for the NEESsoft project is twofold: To provide a methodology to retrofit soft story woodframe buildings to (1) protect life, safety, and property by avoiding soft story collapse and excessive upper story accelerations, and (2) provide a mechanism by which soft story woodframe buildings can be retrofitted using performance-based seismic design (PBSD) to achieve a level of performance commensurate with stakeholders’ target. This vision will be accomplished through a comprehensive combination of new numerical modeling procedures, hybrid testing for validation of two levels of soft story woodframe retrofit and system level validation 
Funding Agency: National Science Foundation
Research Assistant: Chelsea Griffith
Principal Investigator:

John W. van de Lindt, Ph.D.

University of Alabama

Co-Principal Investigators:

Xiaoyun Shao, Ph.D.

Western Michigan University

 

WeiChiang Pang, Ph.D.

Clemson University

 

Michael D. Symans, Ph.D.

Rensselaer Polytechnic Institute (RPI)

 

 

Mikhail Gershfeld, S.E.

California State Polytechnic University – Pomona

to better understand the mechanisms of woodframe collapse and the effect of these two levels of retrofit on system performance. The project includes the following test phases: Slow hybrid simulation at the University of Alabama (UA), Real Time Hybrid Simulation (RTHS) at UA, Hybrid simulation test at University of Buffalo, and STT at UCSD.

Western Michigan University is leading the hybrid testing task essential in gaining a full understanding of soft story collapse mechanisms. Hybrid testing allows seismic evaluation of complex structural systems through substructure system/component testing. Simulation techniques employed in this project will evaluate a full scale wood frame structure with and without various retrofitting options, measuring the margin against collapse, focusing on the effects of a first story retrofit on the upper stories. Experimental methodology is to be developed at WMU’s LESS facility and ultimately carried out on a full-scale model at University of Buffalo’s SEESL facility, where large scale servo-hydraulic actuators will simulate earthquake ground motion and the structure’s dynamic response is recorded.

 

The vision for the NEESsoft project is twofold: To provide a methodology to retrofit soft story woodframe buildings to (1) protect life, safety, and property by avoiding soft story collapse and excessive upper story accelerations, and (2) provide a mechanism by which soft story woodframe buildings can be retrofitted using performance-based seismic design (PBSD) to achieve a level of performance commensurate with stakeholders’ target. This vision has been accomplished through a comprehensive combination of new numerical modeling procedures and full-scale experimental investigation.
In 2013, two full-scale buildings were tested within NEES-Soft. The first is a three-story building which will be tested at the SUNY-Buffalo NEES facility using slow pseudo-dynamic hybrid testing. This test has the main objective of determining the effect of the retrofits on the damage and collapse risk to the upper stories. The second major test was of a full-scale four-story 4,000 sq ft soft-story building. This building was tested at the UCSD NEES outdoor shake table using a variety of different retrofits. These retrofits ranged from FEMA P807 retrofits to performance-based seismic retrofits developed as part of the project.


Western Michigan University led the hybrid testing task in the NEES-Soft project. Hybrid testing allows seismic evaluation of complex structural systems through substructure system/component testing. The NEES-soft project adopts a displacement-based slow pseudodynamic (PSD) hybrid simulation method during which the inertia and damping effects of the whole structure and the hysteresis response of the numerical substructure are simulated computationally, while the restoring force of the experimental substructure is fed back to the numerical simulation to determine displacements through a step-by-step integration. The challenges associated with the UB large scale hybrid simulation are two-fold. One is that a real-time hybrid testing system would be used for the slow hybrid simulation purpose. Another challenge is that the NEES@UB facility is fully scheduled with research projects allowing a very limited onsite period for hybrid simulation controller development. To address these two challenges, a roadmap for the NEES-Soft hybrid simulation controller development was proposed as illustrated below. Benchmark scale and full scale PSD hybrid simulations were conducted at LESS of WMU and the Structural Engineering Laboratory at The University of Alabama (UA) respectively using single actuator test setup. The experiences gained in these two tests were therefore utilized in the development of the full-scale UB hybrid simulation controller that commands four actuators. In addition, a real-time hybrid simulation as also implemented at UA.

 
 
 

Western Michigan University ---- Department of Civil and Construction Engineering

Laboratory of Earthquake and Structural Simulation ---- Last Updated: 12-3-2014