Strengthening and modeling of reinforced concrete frames for seismic forces.

The research described herein is part of a research project which studied repair and strengthening procedures for buildings damaged by the Mexico City Earthquake of 1985. A typical two-story reinforced concrete frame school building was selected as the prototype building for this study. A two-thirds scale model of this reinforced concrete frame was constructed in the structures laboratory at the University of Michigan. This frame was then subjected to three tests of reversed cyclic deformations to obtain insights into the behavior of the frame. The objective of this research was to test and model a typical strengthening scheme for this type of building to gain a better understanding of how the strengthened frame would respond during an earthquake. The testing program indicated that the original and infilled frames experienced distress during testing due to the weak nature of the columns and the beam to column joints. The strengthened frame test showed that when a reinforced concrete jacketing technique was used to strengthen the columns and beam to column joints, the strengthened frame responded much better to reversed cyclic deformations. The nonlinear computer models of the original frame and the strengthened frame were benchmarked against the laboratory test results, and then subjected to actual earthquake acceleration records. The results showed improved behavior of the strengthened frame versus the original frame for each record. The conclusions from this research were that the strengthening technique effectively improved the performance of the frame both in the laboratory and in the computer modeling. The response of the original frame was improved by the strengthening, but care must be taken when applying the reinforced concrete jacket so that the beam reinforcing bars are properly anchored in the beam to column joint areas.PhDCivil EngineeringUniversity of Michigan, Horace H. Rackham School of Graduate Studieshttp://deepblue.lib.umich.edu/bitstream/2027.42/105223/1/9116225.pdfDescription of 9116225.pdf : Restricted to UM users only