Study on Seismic Damage Model of Post-installed Connection Between Steel and Concrete

摘要

As a reliable technology for connecting new steel element to existing concrete structure, the post-installed anchorage is widely used in the field of structural retrofit and strengthening. To study the seismic performance of post-installed connection between steel and concrete and furthermore develop a seismic damage model, a cyclic loading test of four full-scale steel-to-concrete connections with bonded-in rebars has been conducted and factors including embedment depth, shear-span ratio and quantity of bonded-in rebar have been taken into account. Experimental results indicate that bonded-in rebars in all specimens reach yield strength prior to connection failure and tension fracture of bonded-in rebar occurs with slightly concrete spalling in the ultimate state. Increased embedment depth and quantity of bonded-in rebars would significantly improve seismic performance of steel-to-concrete connection. Several existing seismic damage models have been employed to evaluate the serviceability for post-installed anchorage, respectively. The prediction results compared with test data show that current models are not suitable for seismic damage assessment of steel-to-concrete connection by post-installed anchorage. Therefore, based on the experimental data, a revised model has been provided for post-installed connection under earthquake action. A combination coefficient η is introduced in the model which is defined to present the interaction between deformation and energy accumulation caused by cyclic loading. The revised model presents satisfactory serviceability in post-earthquake evaluation. A definition of five-level damage states with explicit threshold values of D has been provided for evaluation post-earthquake status of steel-to-concrete connection.