A Novel Design Procedure for CFRP-Strengthened Concrete-Filled Steel Tubes to Resist Impact Loads

Abstract

AbstractConcrete-filled steel tubes (CFSTs) have received growing attention, owing to their rapid construction, reduced labor requirement, and reasonable material cost. While in service, the CFSTs can be subjected to a variety of environmental and mechanical stressors, which make them vulnerable to subsequent loading events. Considering the high durability and strength-to-weight ratio of carbon fiber-reinforced polymer (CFRP), it has been used to enhance the structural response of the CFSTs under service loads. However, there is still a research gap regarding the response of CFRP-strengthened CFSTs subjected to lateral loads, such as vehicle collision, as well as water- and wind-borne debris impact. This motivation led to the development of a computational framework to evaluate the response of CFSTs with and without CFRP subjected to impact loads. In this study, a set of representative finite-element (FE) models supported by the experimental tests is developed for impact simulations. The response of the CFSTs is studied using a range of response measures, including internal forces and deflections, as well as the energy absorbed during impact. The investigation is further extended to a systematic effort on the influence of various design parameters related to CFRP, concrete, and steel tube. From the conducted investigations, the absorbed energy is identified as the critical parameter for such members’ design under impact loads. A new procedure to design the CFRP-strengthened CFST beams subjected to impact loads is then proposed. The accuracy of the presented method is confirmed by comparing the absorbed energy from the section analysis to that from high-fidelity simulations. This study is concluded with a detailed example, illustrating the strengthening of CFSTs using CFRP sheets.KeywordsCFRPConcrete-filled steel tubeLateral impactDesign methodAbsorbed energy