Research On The Shear Behavior Of Interior Joints With High-Strength Lightweight Reinforced Concrete

High-strength lightweight aggregate concrete(HSLWAC)has lighter weight,higher strength,better fire resistance.It is a kind of green building material that has promising developing prospect.By using HSLWAC,the building self-respect can be reduced,which reducing the seismic response caused by the earthquake ground motion.However,the toughness of high strength lightweight aggregate concrete is significant.Which makes the structure is easy to emerge brittle failure under cyclic loading.So it is necessary to research the seismic behavior of frame joint with HSLWAC which acts as the key component and hinge of force transferring of the reinforced concrete frame structure.According to the experimental study,theory analysis and numerical simulation,the shear performance of HSLWAC frame joint has been investigated.The main research contents as follows:(1)Based on the experimental investigation on four HSLWAC interior joints under low reversed cyclic loading,the shear behaviors of specimens were obtained.The shear capacities of four specimens were calculated using the current code of JGJ12-2006,ACI318-14 code,ACI352R-02 code and EC2 code.The test results are compared and analyzed with predictions.It is indicated that the calculation results using the current code of JGJ12-2006 are more conservative than the ACI318-14 code,ACI352R-02 code and EC2 code.(2)Based on the modified compression field theory(MCFT),the shear analysis model of HSLWAC interior joint was estimated.Combined with the Attaalla shear model,good predictions between experiment tests and predictions is achieved by calculations of 17 test data of lightweight aggregate concrete interior joints specimens.It also shows that MCFT model can predict mechanical behavior of shear specimen before the ultimate stage.The Attaalla shear model can predict the stress-strain relationship of specimen during the loading process and has considered the compression softening effect of cracked concrete.(3)Based on the software Abaqus,the finite-element simulation of this kind joint was completed.Comparing the simulation results to test results,it can be found that the failure process and the shear strength of joints are consistent,but there is no obvious shrinkage phenomenon in the hysteresis curve.Changing numerous parameters of those models to research the influence of shear reinforcement ratio and axial compression ratio,it shows that the influence rules of these two factors are similar between HSLWAC interior joints and normal weight aggregate concrete(NWAC)interior joints.The relative research in this paper will have theoretic importances and major implications for the understanding of HSLWAC joint failure mechanism and ensuring the safety of HSLWAC frame under seismic action.It also will provide a basis for the widely use of green environmental protection material HSLWAC in the frame structure.