International Concrete Abstracts Portal

Title: Elastic Joint Connections for Precast Concrete Frames Subjected to Large Seismic Loads

Author(s): B. Rogers and D. Shelangoskie

Publication: Special Publication

Volume: 94

Issue:

Appears on pages(s): 855-882

Keywords: columns (supports); connections; deformation; dynamic loads; earthquake-resistant structures; elastic properties; embedment; girders; framing systems; joints (functions); lateral pressure; precast concrete; structural design; tests; Construction

Date: 7/1/1987

Abstract:
Central to the design of the Intermountain Power Project (IPP) mechanical cooling towers was the ability to configure connections between precast concrete members so that large horizontal seismic forces could be transferred between beams and girders and between girders and columns. Complicating the task of connection design were substantial thermal loads and severe environmental conditions. To solve these and related design questions, a testing program was undertaken using «-scale models of certain key joints in the structure. This paper presents a description of the testing program, a brief description of the structural system in which the joints were located, and the results and conclusions of the tests. Principal among the conclusions is the recognition that embedded metal pins used to transfer forces between discrete members must not only be carefully detailed, but they also must accommodate substantial elastic deformation at the joint if failure below acceptable force levels is to be avoided. In the IPP, this was accomplished by the introduction of a confined viscoelastic medium surrounding the pin. This simple addition to the joint configuration increased the force transferred through the connection by a factor of 2.5 to 3 while limiting deformation to acceptable values.