Experimental studies and numerical simulation of behavior of RC beams retrofitted with HSSWM-HPM under impact loading Weizhang Liao a,⇑ , Miao Li a , Wei Zhang a , Zhimin Tian b a Beijing Higher Institution Engineering Research Center of Civil Engineering Structure and Renewable Material, Beijing University of Civil Engineering and Architecture, Beijing 100044, China b Beijing Canbao Institute of Architectural Design, Beijing 100850, China article info Article history: Available online xxxx Keywords: Impact loading Drop weight impact test High Strength Steel Wire Mesh and High Performance Mortar (HSSWM-HPM) Explicit finite element analysis abstract High Strength Steel Wire Mesh and High Performance Mortar (HSSWM-HPM) are widely used for struc- tural reinforcement and retrofit. Recent research suggests that HSSWM-HPM can be applied to enhance seismic loading-resistance of structures. In this study, the mechanical performance of reinforced concrete (RC) beams covered with the HSSWM-HPM under impact loading were evaluated using both laboratory experiments, and numerical simulations. In the laboratory experiments, the performance of eight full- size beams, including five retrofitted RC beams and three un-retrofitted RC beams, subjected to the drop-weight impact loading and static loading were evaluated. During the drop-weight impact tests, the contributions of the following critical parameters, including the impact loads, strains, accelerations, velocities, and deflections of the beams, and residual damage, were studied and compared among differ- ent specimens. Another comparative study on the failure pattern and the impact resistance of beams with and without reinforcement were performed in the commercial finite element software LS-DYNA. A gen- eral prediction of response time histories and maximum mid-span deflections of the beams were obtained from LS-DYNA. The results obtained from both laboratory experiments and finite element anal- yses indicated that the impact resistance and ductility of the RC beams were significantly improved after retrofitted with HSSWM-HPM. Ó 2016 Elsevier Ltd. All rights reserved. 1. Introduction Reinforced concrete structures are widely used in civil engi- neering. In recent years, RC structures are exposed to extreme dynamic loading conditions due to direct impact. Typical examples include heavy objects falling on RC structure in constructions, splash impact during explosions, ships crashing into the bridge piers, moving vehicles hitting guardrails. The analyses of structures under dynamic loads are often complicate due to the unique char- acteristics of the loads such as high intensities, extreme short dura- tion, and concentrated damages. Impact loading is a dynamic effect, and the duration of loading is measured in milliseconds. Such short duration can be 1000 times shorter than earthquakes [1]. Meanwhile, considering the plasticity of reinforced concrete, the analyses and design of RC structures under dynamic loading are very complicate; however, traditional static analyses cannot take dynamic effects into consideration which leads to inaccurate prediction of RC structure performances under dynamic loads. A large number of tests have been conducted in order to inves- tigate the structural response of reinforced concrete (RC) beams and slabs subjected to different rates of concentrated loading applied at the mid-span of the RC specimens. Based on the avail- able test data [2–9] and numerical evidences [4,5,10], the recorded dynamic response exhibits substantial differences compared to that established based on static testing. The discrepancy becomes more significant as the loading rates increase. In order to improve the impact resistance of RC structural com- ponents, such as beams, columns and slabs, retrofitted with steel plates [11–14], FRP [15–21] and High Strength Steel Wire Mesh and High Performance Mortar (HSSWM-HPM) have been studied and used in engineering practice. Base on the retrofitting technology on ferrocement [22] and wire rope units [23,24], a new retrofitting technology with steel wire mesh and polymer mortar attached to concrete components were developed by Kim and Choi [25]. Although HSSWM-HPM laminates were being increasingly used to repair buildings, limited studies were carried out on the effect of impact loads on structures repaired with HSSWM-HPM laminates. http://dx.doi.org/10.1016/j.engstruct.2016.07.040 0141-0296/Ó 2016 Elsevier Ltd. All rights reserved. ⇑ Corresponding author. E-mail address: liaoweizhang@bucea.edu.cn (W. Liao). Engineering Structures xxx (2016) xxx–xxx Contents lists available at ScienceDirect Engineering Structures journal homepage: www.elsevier.com/locate/engstruct Please cite this article in press as: Liao W et al. Experimental studies and numerical simulation of behavior of RC beams retrofitted with HSSWM-HPM under impact loading. Eng Struct (2016), http://dx.doi.org/10.1016/j.engstruct.2016.07.040