Experimental Study On Impact Performance Of Hybrid PVA Fibers Reinforced Concrete Piers

A large number of ship collision accident analyses have shown that the bridge damage is mainly happen to the lower part of the structure,therefore the piers require more focus on improving impact resistance performance when designing.At the same time,due to the low tensile strength,poor toughness and difficult control of crack width,the durability of concrete is greatly reduced,thus affecting the service life of the structure.As a high-quality green material,Polyvinyl Alcohol Fiber?PVA?has good hydrophilicity,and has good bonding properties with cement based materials.Adding proper amount of PVA fiber into concrete can increase the toughness and initial tensile strength of concrete,so as to effectively inhibit the generation and development of early shrinkage cracks and reduce the invasion of corrosive medium,so as to improve the durability of concrete structure.Therefore,studying the impact performance of fiber reinforced concrete under horizontal impact load is of practical significance for the piers which may be impacted under coastal corrosive environment.Based on the horizontal collision model tests of cars and piers,the performance of hybrid PVA fiber reinforced concrete piers under horizontal impact load is studied and compared with ANSYS/LS-DYNA numerical simulation results.The main research work is as follows:?1?Through the horizontal impact model test of the car and the pier,analyzed the impact force curves,displacement time history curves,concrete strain curves and steel strain curves of dynamic responses and damage of concrete and cracks for the anti shock performance of hybrid PVA fiber reinforced concrete piers.?2?Through analyzing the maximum impact force,the maximum displacement of the top of the specimen,the main strain,the concrete strain and the ultrasonic parameters and the crack development of the reinforced concrete pier specimens of different hybrid PVA fiber reinforced concrete bridge piers,the results show that after the addition of PVA fiber,the energy dissipation capacity is enhanced,the impact toughness is improved,and the crack width is also effectively controlled.Among them,the hybrid m?PVA⁶?:m(PVA¹⁹)=4:1 is the most effective way to improve the impact performance of piers.?3?Through ANSYS/LS-DYNA finite element software,the horizontal impact model test of hybrid PVA fibers reinforced concrete piers was simulated,at the same time,the results of the numerical simulation are close to the experimental results.