Experimental And Analysis Investigations On Steel-UHPFRC Composite Fender Structures Subjected To Impact Loading

Vessel collision with bridges occur frequently worldwide and kinds of anti-collision measures and devices are implemented to avoi d or reduce the damage caused by vessel collision in bridge engineering.However,steel fender,which is used widely,have many disadvantages,such as,steel panels of steel fender penetrated by vessel,low energy absorption efficiency and stability,triggering fire during the collision between bridge and vessel,poor durability,and so on.Associate Prof.Fan Wei of Hunan University has proposed a native steel-UHPFRC composite fender which can solve the disadvantages of steel fender and has great potential and good future prospects.The performance of new steel-UHPFRC composite fenders are investigated by falling weight impact test and numerical simulation in this study.The main contents and conclusions of this study are summarized as follows:(1)Corrugated steel-UHPFRC(Ultra-High Performance Fiber Reinforced Concrete)and steel-NC(Normal Concrete)composite fender are tested by drop hammer system to investigate the influence of the thickness of corrugated steel plate,material of panel,space of rebar and the shape of hammer on steel-UHPFRC composite fender.Displacement gauge and strain gauge are used to record the displacement of composite structures and strain of corrugated steel plate.In addition,high speed camera is implied to record the deformation of composite structures.Generally,the most sensitive factor influencing overall deformation of a composite structure is thickness of corrugated plate,followed by material of outer panel and then hammer shape as well as reinforcement space in outer UHPFRC panel.(2)Based on analyzing and comparing the constitutive model of normal concrete material in LS-DYNA,the Continuous Surface Cap Model(CSCM)was modified combined with UHPFRC material test(uniaxial test,biaxial test triaxial test and hydrostatic compression test)datas to simulate the UHPFRC structure members subject to impact loads.The modified Karagozian & Case concrete(KCC)model and CSC model has been used to simulate the UHPFRC beam subject to impact loads reported in literatures.The results show that the modified KCC model proposed in literature has some deficiency to predict the response of UHPFRC beam subjected to impact load.However,the impact-induced response of UHPFRC beam obtained using the modified CSC model agree very well with the experimental results.(3)Based on the nonlinear explicit dynamic finite element(FE)technique,the FE model of corrugated steel-UHPFRC composite structures is developed.The modified CSC model is used to simulate UHPFRC.Whether impact force or displacement of corrugated steel-UHPFRC composite structure obtained using LS-DYNA agree well with experimental results.These imply that the method of establishing the model of corrugated steel-UHPFRC composite fender subjected to impact load is effective and reasonable in this paper.What's more,it provides a basis for the application and analysis for these new composite fender in practical engineering.(4)Taking the actual engineering as an example,the performance of the corrugated steel-UHPFRC composite fender is evaluated by the numerical simulation method established in this paper.The results show that the proposed steel-UHPFRC composited fender was demonstrated as being capable of greatly decreasing the impact force,extending time of impact force,and decreasing the damage extent of the bridge and aberrant vessel.All in all,the proposed steel-UHPFRC composited fender has excellent anti-collision performance.According to the great impact resistance and durability of UHPFRC,the new corrugated steel-UHPFRC composite fender will overcome the disadvantages of steel fender and has great potential and prospect in bridge engineering.