Title: Seismic Retrofit of Reinforced Concrete Buildings Designed for Gravity Loads: Performance of Structural Model

Author(s): Joseph M. Bracci, Andrei M. Reinhorn, and John B. Mander

Publication: Structural Journal

Volume: 92

Issue: 6

Appears on pages(s): 711-723

Keywords: concretes; ductility; earthquake-resistant structures; frames; infilled frames; loads (forces); masonry; post-tensioning; strength.

DOI: 10.14359/9665

Date: 11/1/1995

Abstract:
A partially prestressed concrete alternative and two masonry retrofit alter natives are analyzed for improving the local and global response performance of reinforced concrete frame structures designed only for gravity loads and constructed in low-to-moderate seismic zones. The objective of these retrofits is to reconfigure the structural failure mode by averting a catastrophic soft-story collapse and enforcing a more ductile beam sidesway mechanism. A prestressed concrete jacketing alternative to limited columns was selected to retrofit the one-third scale model RC frame building that had been previously tested by Bracci, Reinhorn, and Mander. 1-3 The seismic response of the retrofit model structure was investigated experimentally using the shaking table at SUNY at Buffalo. A comparison is made of the experimental frame response before and after retrofitting. It is concluded that the seismic performance of vulnerable (soft-story prone) GLD frames may be effectively enhanced by strengthening limited columns and thus, changing the failure mode to a beam sidesway mechanism with acceptable story deformation levels.