Severe damage to acceleration sensitive nonstructural components in recent earthquakes has resulted in unprecedented losses. Recent research has been aimed at increasing the understanding of acceleration demands on nonstructural components in buildings. This investigation subjects a set of four special moment resisting frame (SMRF) building models to a suite of 21 far-field ground motions using the incremental dynamic analysis procedure. Full three-dimensional models including floor slabs are used to extract both the horizontal and vertical responses. Floor acceleration response spectra are generated to assess the acceleration demands on elastic nonstructural components. Changes to the current code provisions that include the influence of structural period are proposed. An alternative design approach that directly amplifies the ground acceleration spectrum to achieve the desired floor acceleration spectrum is presented.

The expansion gap closure in seat-type bridge abutments during strong earthquakes results in seismic pounding. This pounding significantly affects the behaviour of the bridge and yet there are limited studies focusing on this impact. As a part of the Federal Highway Administration (FHWA) funded project, a 2/5 scale curved bridge model was constructed to be tested on the four shake tables in the University of Nevada, Reno Large Scale Structures Laboratory. One of the six configurations of the bridge model was designed to study the seismic pounding at the abutments with an equivalent nonlinear backfill soil. An abutment configuration was designed for the experiment to investigate the abutment impact accounting for the nonlinearity of the backfill soil. In this configuration, the superstructure was forced to impact a backwall supported by nonlinear springs with initial stiffness similar to that of typical embankment soil. The preliminary experimental results presented in this paper demonstrate that the closure of the expansion gap significantly influences the global response of the bridge system. Experimental measurements of the impact forces is planned to be used to calibrate numerical impact models.

Seat-type bridge abutments consisting of expansion gaps and sacrificial shear keys significantly affect the response of bridge during strong earthquakes. Seismic pounding between the bridge deck and the abutment backwall caused by expansion gap closure may alter the dynamic characteristics consequently affecting the demands on various bridge components. Additionally, the loss of sacrificial abutment shear keys changes the support boundary condition and may significantly increase the demands on the bridge piers. A small scale parameter study investigates the influence of ground motion and bridge curvature on the performance of seat-type bridge abutments. Straight and highly curved configurations of a benchmark bridge are subjected to two suites of motions, on set with and the other without large velocity pulses. The vulnerability of the bridge configurations are compared using component fragility analysis. It is shown that bridges are more vulnerable to ground motions with large velocity pulses and that curved bridges are more likely to experience column damage and abutment unseating compared to straight bridges.