SEISMIC PERFORMANCE STATES OF PRECAST CONCRETE CLADDING CONNECTIONS

摘要

Experimental testing of connections used to support precast concrete cladding was conductedfor seven full-scale tests. These tests represented in-plane or out-of-plane movement of a panelsystem, resulting in loading that the connection is intended to resist or not intended.The objectives were to determine the true force-deflection relationships of the connectionsallowing for accurate pushover analysis. Using pushover analysis, various performance stateswere determined.Specimens were built in the laboratory and tested under monotonic loading. Force anddeflection data were monitored using both manual and automated data acquisition systems.Push-pull connections and lateral seismic connections were tested. Data was reduced toengineering terms and stiffness and the displacement for various FEMA-273 Performance Stateswas determined.For 25-mm Push-pull connections loaded in axial tension or compression, the performance wasvery ductile, with deformations over 150 mm achieved without loss of strength. However, thisdeformation resulted from severe bending of the supporting plate and showed very low stiffnesswhen compared to that expected for such connections. When these connections were loaded inbending, they also failed in a ductile mode. No slip was seen between the unwelded platewashers and the supporting bracket. Significant stiffness was provided when the connectingrods were short (150 mm).The Lateral Seismic connection also failed in a ductile mode when loaded in-plane, the directionof its' intended use. However, when loaded out-of-plane, this connection showed significantstiffness when compared to the Push-pull connection with which it is partnered. As a result, theLateral Seismic connection failed with limited deformation (20 mm), resulting in the connectionbeing unable to resist any in-plane motion occurring in the panel.