Shear Performance Of Low-rise RC Shear Wall Under Cyclic Loading

Obvious shear failure often occurs to low-rise RC shear wall subjected to cyclic loading.If the existing calculation methods for shear wall,applied generally for cantilever shear wall with bending failure mode,are used to predicted shear capacity of the low-rise RC wall,there will be a larger deviation between the prediction and test results.And currently,cracking angle of the low-rise RC wall is mainly dependent upon its geometrical dimension,thus neglecting the influence of vertical loading,etc.Therefore,it is of much necessity to analyze shear performance of the low-rise RC wall by using rational shear theories,and study the effectiveness of these shear theories for the wall.Meanwhile,the correlation between the cracking angle and influence factors should be analyzed.In this article,on the basis of cyclic loading tests,the shear performance of the low-rise RC wall has been studied,as follows:Firstly,Softened Truss Model(STM),Modified Compression-Field Theory(MCFT)and Softened Strut-and-Tie Model(SSTM),were used to analyze elaborately the shear mechanism of the low-rise RC wall from different perspectives,which would prepare for the following analysis and calculation.STM,MCFT and SSTM have something similar in theoretical frameworks but different in constitutive laws,etc.Secondly,taking into consideration the correction between the cracking angle and these factors: geometry dimension,mechanical properties of concrete and reinforcement,vertical load and cross-section shape,a new cracking angle calculation method was obtained by normalization method based on cracking patterns of seventy-four low-rise RC walls at failure.Moreover,compared with the other two methods,the new method was verified by cracking patterns of four low-rise RC walls.It is indicted that the new method is of better ability to predict cracking pattern of the low-rise RC wall under cyclic loading.Apart from these,STM,MCFT,and SSTM were used to calculate the shear capacity of ninety-two low-rise RC walls.Based on test results,the effectiveness of three shear theories for predicting the shear capacitywas obtained by discrete analysis and outlier analysis.Results show that(1)the effectiveness of SSTM is best,(2)the effectiveness of STM and MCFT are worse,especially for the wall subjected to larger vertical load,and(3)the propose cracking angle calculating method is suggested when STM and MCFT are used to predict the shear capacity.Afterwards,six low-rise RC shear walls with different aspect ratios were simulated by finite element software ABAQUS.It is indicated that the DAMAGETs and the load-displacement curves agree well with test results.And the differences between their peak loads and test,theoretical values are mostly within 25%.Thus the finite element model can be applied for shear analysis of the low-rise RC wall.At last,RC composite slabs with precast ribbed panels(CSPRP)were regarded as the low-rise RC shear walls.The new cracking angle calculation method and above shear theories were used to analyze the impact of prestress on bearing capacity and crack development direction,respectively.It is indicated that prestress has lower impact on the cracking angle and shear capacity of CSPRP.