Experimental Study On The Performance Of Lap-spliced Reinforcement In Ultra-high Performance Concrete

Among the assembled concrete structures,the reliability of steel brakes is very important.However,there are still many shortcomings in existing connection technology.Ultra-high performance concrete(UHPC)is a concrete material with excellent performance,which can greatly improve the crack resistance and durability of the structure.Existing studies have shown that the UHPC can reduce the bond length by increasing the bonding performance,however At present,the research on steel balance is mainly focused on the lap of steel bars in ordinary concrete.It is also relatively small for the research of steel barrier performance in UHPC.Based on this,this paper studies the reinforcing performance in UHPC.The main contents are as follows:(1)Monotone loading and one-way repeat loading in 26 UHPCs were monotonized,and different parameters were studied the effects of steel barrier performance in UHPC.The test results show that the destruction form of the lap test piece mainly has two forms under the monotonic pull load and one-way repetition load.As the lap length and the diameter of the steel bar increase,the lap strength between the steel bars and the UHPC decreases,and the increase in the thickness of the protective layer will increase the lap strength of the lap test piece;(2)By analyzing the experimental data of each group of test pieces,fitting the calculation formula of the slip value of the slip value of the slip value corresponding to the limit lap strength and the limit load of the lap test piece under one-way repeat load,and derived the critical lap The length of the length and the limit lap length,the application of the formula is verified by the test data of this article and other documents,and the rationality of the formula;(3)Analyze the experimental data of each group of lap test pieces,fit the lap intensity calculation formula of the lap test piece,and derive the functional relationship of critical lap length.The analysis results show that the diameter is 20 mm in the R120 UHPC,the thickness of the protective layer is 45 mm,the critical yield lap length is 4.8d under monotonic draw,the critical limit is 7.3d,in one-way repeat load The critical yield lap length under the action is 5.7d,the critical limit is 8.7d.(4)The three-fold line model of the bonding migration of the lap tester is proposed.The model is considering the effects of lap length,protective layer thickness,steel diameter and other factors;use ABAQUS finite element software to verify the accuracy of the constant model and,Parameterized analysis of the lap test piece.This article contains 64 figures,35 tables,83 references.