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Seismic Resistance of Precast Concrete Panel Buildings, Preliminary Study. Proceedings of the National Meeting of the Universities Council for Earthquake Engineering Research (4th), Held at University of British Columbia, Vancouver, British Columbia, Canada, on June 28-29, 1976.
Becker, J. M.
National Science Foundation, Washington, DC. Applied Science and Research Applications., June 29, 1976, 6 p.
To provide a focus for analytical research, a Large Precast Panel Building (LPPB) system developed in New England and now used throughout the United States, was chosen for detailed study. This structure is a post-tensioned cross-wall system using prestressed hollow-core floor planks. The load bearing shear walls are constructed out of precast concrete panels that are 8 feet in height and can range in length from 12 feet to 48 feet. These panels are post-tensioned together creating a horizontal connection in which grout is placed in the space left by the floor planks and the next panel is then bedded in dry-pack concrete. The post-tensioning force and the structures own weight act together as a prestressing force in the resistance of overturning moments and participate in developing the friction mechanism for shear transfer across the connection, which is considered soft. To examine the potential effects of the nonlinearities associated with soft connections, it was decided to separate the stiffness parameters for the connection area. This separation allowed for the independent variation of the modulus of elasticity and the shearing modulus. An effective shearing modulus could then be assumed to account for the possibilities of both distortion and slippage. Three dynamic models were examined: a beam model, a simple finite element model, and a statically condensed super element model. Work is also being done to compare results of the parametric studies of strength criteria for the structure. Initial indications are that overturning moments will cause tension across the connection area before friction mechanisms will allow slippage due to shear.
Buildings; Earthquake engineering; Earthquake resistant structures; Seismic design; Shear properties; Shear walls; Concrete construction; Precast concrete; LPPB systems; Large precast panel buildings; Panels; Dynamic structural analysis