Half Scale Shake Table Test of a 4 Story Reinforced Concrete Building with Eccentric Shear Walls

A half-scale shake table testing program was conducted at NEES@UCSD. The testing program occurred with the collaboration of large group of industrial partners and design consultants. The project is a multi-university effort to develop and evaluate the potential for a new floor anchorage system that lowers seismic demands in an earthquake. The so-called "inertial force-limiting floor anchorage system (IFAS)" has the potential to significantly reduce floor accelerations and diaphragm forces in a building structure, thereby lowering seismic demands on the lateral force resisting system (LFRS) and reducing overall structural/nonstructural damage.

The shake table test specimen was a four-story reinforced concrete building with an eccentric shear wall layout. Three phases were tested at NEES@UCSD:
Phase 1: This phase evaluated the performance of the structure using innovative special anchorage system. The LFRS was unbonded post-tensioned (PT) precast hybrid rocking wall.
Phase 2: This phase provided a direct comparison of a "traditional" anchorage system. In this phase, the special floor anchorage system is replaced by a traditional diaphragm connection (JVI PSA). The structure is subjected to same sequence of earthquakes to provide a direct comparison to Phase I.
Phase 3: This phase focuses on a traditianal shear wall structure. The wall post tensioning bars are removed and the walls are grouted into pocket foundations to create Precast Emulative Shear Walls. These walls employed high strength reinforcement. The eccentric layout again induced twisting of the structure in plan, causing simultaneous bi-directional motion and yaw of the walls.

The IFAS design for the shake table test was developed through nonlinear computational analysis at University of Arizona. The IFAS prototype used in the shake table was developed through large-scale component testing at NEES@Lehigh.