Experimental study on seismic behavior of repaired tunnel form building under cyclic loading

Abstract

It is very important to determine the seismic behavior of the multi-story tunnel form buildings especially in medium and high seismic regions. The aim of this study is to determine the overall seismic behavior of unrepaired and repaired specimens under the in-plane lateral cyclic loading. The damaged specimen was repaired by enlarging the external shear wall, affixing the joints with steel plate and steel angle and finally wrapping the specimen with CFRP. A one-third scale double unit of tunnel form buildings was designed using non-seismic code of practice (BS8110), constructed and tested under in-plane lateral cyclic loading. The specimen was tested starting from ± 0.01, ± 0.1, ± 0.25, ± 0.5, ± 0.75%, until ± 2.3% drift. The repaired specimen was retested following a similar pattern of drifts as before repaired. The hysteresis loops of repaired specimen were modeled using HYSTERES program in Ruaumoko 2D. Experimental results showed that the repaired specimens improved in term of damages, 19.35% of lateral strength capacity, 6.79% of stiffness, 34.87% of ductility and 31.11% of equivalent viscous damping. There was good agreement between experimental hysteresis loops and modeling hysteresis loops. Thus, the damaged tunnel form buildings can be repaired, retrofitted and strengthened using the combination materials of steel plate, steel angle and CFRP.