Seismic strengthening and rehabilitation of RC frame structures with weak beam-column joints by installing wing walls

摘要

A substantial number of reinforced concrete (RC) buildings with seismically substandard beam-column joints have suffered severe damage in past earthquakes. This paper focuses on the installation of RC wing walls to upgrade weak beam-column joints and to rehabilitate those moderately damaged by earthquakes. Cyclic load tests were conducted using four specimens representing an exterior 1.5-story frame with a beam-column joint. The first specimen was for a benchmark specimen, the second and third were strengthened by installing wing walls to the interior or exterior of the columns, and the fourth was rehabilitated after the existing frame was moderately damaged. Consequently, the benchmark specimen suffered severe damage to the beam-column joint. The two strengthened specimens showed different damage behaviour: the second one was ductile with beam yielding, and the third one prevented the column-sway mechanism. For the rehabilitated specimen, the beam yielded and the maximum strength was nearly equivalent to that of the second specimen in which wing wallswere installed to the interior side of the columns, but damage to the joint was more severe. The test results indicated that the developed wing wall installation method is practical not only for strengthening poorly detailed beam-column joints but also for rehabilitating such joints moderately damaged by earthquakes.