In-Plane Behavior of Steel-Plate Composite Wall Elements under Intermediate High Temperature

To explore how steel-plate composite (SC) walls response to in-plane loading is essential for SC structural design, especially combined with thermal loading. This work focuses on the intermediate high temperature (<= 400 degrees C) that is often considered during design process. Individual mechanical behavior of steel plate and concrete in SC walls under intermediate high temperature are studied. Thermoplasticity is applied to describe steel plate as 2D element, by which plastic flow combined with mechanical property degradation can be considered. High-temperature mechanical behavior of concrete is very complicated. In this study, strain of concrete at high temperature is decomposed into transient thermal strain, free thermal strain, and mechanical strain. By elaborating the physical meaning of transient thermal strain and selecting mathematical models for every strain component, deformation of high-temperature concrete can be calculated. To study the in-plane behavior experimentally, an SC panel test with in-plane shear and thermal loading was conducted. Steady thermal state and transient thermal state were considered in two specimens, respectively. Comparison between test data and theoretical calculation results shows good agreement. Verifications from other researchers' tests show that the model can be applied to general situations of in-plane loading combined with intermediate high temperature.