Test and numerical study on seismic performance of demountable and replaceable steel beams connected with T-shape steel

Here, a kind of demountable and replaceable steel beams connected by T-shaped steel was proposed. T-shaped steel could concentratively dissipate seismic energy under earthquake action, and structural functional recovery could be realized by replacing T-shaped steel after earthquake. By reasonably designing flexural bearing capacity relations among T-shaped steel connection, the middle segment and cantilever segment of the steel beam, the allowable range of weakening coefficient of design load-bearing capacity was defined to realize the yield mechanism for concentrated damage energy dissipation of T-shaped steel and keeping the elasticity of the middle segment and cantilever segment of the steel beam. In order to realize the expected damage and the optimal energy dissipation effect of T-shaped steel connectors, 4 T-shaped steel connectors were designed with different cross-sections and materials for web. Low cycle reciprocating loading tests and finite element analyses were conducted for demountable and replaceable steel beam specimens connected with T-shaped steel. The results showed that demountable and replaceable steel beams connected by T-shaped steel can realize the expected yield mechanism to reach the goal of concentrated energy dissipation of T-shaped connectors; residual deformation and bolt stress of T-shaped steel web can satisfy detachment and replacement conditions, and the structural function remains unchanged after detachment and replacement to, which indicates that the desirable replaceable mechanism is achieved. Plastic deformations of T-shaped steel connectors with dog bone type web cross-section are more uniform, energy dissipation area is larger, and energy dissipation efficiency increases by about 30%, replacement time and residual deformation are not obviously different from those with ordinary cross-sections, so it is recommended to use dog bone type web cross-section for web; using low yield point steel can improve energy dissipation efficiency of T-shaped steel by about 40%, when the design load-bearing capacity coefficient is reasonable, low yield point steel can be chosen for T-shaped steel web. Based on test and finite element results, considering the demountability and replaceability of T-shaped steel connectors and steel beam material utilization weakening coefficient of design load-bearing capacity is suggested to be 0. 65-0. 85. © 2024 Chinese Vibration Engineering Society. All rights reserved.