CHEN Gongqing, WU Hao, L Jinxian, CHEN De
JOURNAL OF VIBRATION AND SHOCK. 2024, 43(3): 93-104.
As non-structural members, masonry infill walls are often neglected in the blast-resistant analysis of structures. However, serious damage occurs to masonry infill walls in explosion accidents, which affects the propagation of blast wave, its interaction with structures and the degree of damage to the structure. This paper aims to evaluate the effect of masonry infill walls on damage and failure of RC frame structure under external blast loadings based on refined numerical simulation approach. Firstly, the finite element software LS-DYNA is used to reproduce the near-range explosion tests of typical masonry infill walls and masonry-infilled RC frame, which verifies the applicability of the simplified micro-modelling approach, material models and parameters, as well as the blast loading applied approach based on Arbitrary Lagrangian-Eulerian (ALE) and the Fluid-Structure Interaction (FSI) algorithm. Furthermore, combined with the structural hybrid element modelling approach, the numerical simulation was carried out on the dynamic behavior of the typical 6-story bare and masonry-infilled RC frame structure with 6-, 7- and 8-degrees seismic precautionary intensities under the explosion of sedan bomb (454kg equivalent TNT specified by Federal Emergency Management Agency) at the bottom edge column. The propagation of blast wave, as well as dynamic response, damage pattern and collapse-resistance mechanism of the structures were examined. It derives that: the masonry infill walls can effectively block the inward propagation of blast wave and reduce the peak overpressure on the adjacent internal column by 95%, and thus relieve the damage degree of the internal structural members. However, the structural damage at the head-on blast face is aggravated, e.g., compared with bare frame, the horizontal displacements of target column in masonry-infilled RC frame with three seismic precautionary intensities increase by 21.4%, 31.1% and 14.8%, respectively. The vertical displacement of target column at top floor in the bare and masonry-infilled RC frame with different seismic precautionary intensity is basically same. Therefore, the effects of seismic design and masonry infill walls on the overall collapse behavior of structures can be ignored under the external explosion of sedan bomb.