Precast Diaphragm Response in Half-Scale Shake Table Test

This paper summarizes key diaphragm response parameters observed during the shake table testing of a three-story precast concrete structure built at half-scale. The test structure geometry possessed an aspect ratio in plan and structural wall layout to form a diaphragm-critical condition. Each floor of the structure incorporated a different precast concrete diaphragm construction technique: untopped double tees, topped hollowcore, and topped double tees. A new seismic design methodology was used to design and detail the diaphragms. The test structure was subjected to input ground motions of increased intensity in a series. The series totaled 16 strong ground motions, consisting of design basis and maximum considered earthquakes for which the diaphragms were designed. The primary objectives of the testing program were to examine the behavior of precast diaphragms within the structural system, demonstrate the seismic performance of the precast diaphragms designed with the new design methodology, and calibrate analytical models for the wider research program. This paper describes diaphragm global and local responses. The responses were interpreted in terms of expected diaphragm performance. Design conclusions were drawn based on the observed diaphragm seismic response.