Significance Analysis Of Influence Parameters On Shear Behavior Of Deep Flexural Member

Members are referred to reinforced concrete deep flexural members when span-depth ratio is less than 5.It is significantly different from normal beams as its various influence parameters and complex shear mechanism.There are two calculation methods on shear capacity of deep flexural members,one is called “mechanism model” which shear phenomenon and influence parameters are interpreted and reflected through the laws of optimized shear models.But its calculation process is complex and significantly affected by size effect.The other is called “probabilistic model” which based on principle of statistics and results of tests.Models are set up by considering the significance of influence parameters and the level of reliability.Its calculation process is concise but easily influenced by sample size and also short of theoretical models.If combine two methods on the significantly effect of influence parameters,accuracy can be increased.It provides theoretical significance and practical value to advance the calculation and design of deep flexural members.Based on code provisions,this paper collected 691 test results to reasonably quantify the significant influence parameters on shear capacity of deep flexural member.Compare the calculation results of GB50010-2010,ACI318-08,CSA A23.3-04,EC2.Through correlation analysis,single influence parameters and combination factors are quantifiably evaluated by Kendall,Spearman and Partial Correlation Coefficient.Four comprehensive indexes are integrated by principal component analysis to analyze the contribution ratio of actual shear capacity.The results show that:1?Calculated results by code provisions agree well with test results.GB50010-2010 results are more conservative when shear-span ratio is smaller.Models based on strut-and-tie such as ACI318-08,CSA A23.3-04 and EC2 are unsafe when shear-span ratio is larger.2?For single influence parameters,the most significant factor is cylinder concrete strength fc',section size h0 and b,shear-span ratio a/h0 are also significant.For combination factors,the influences of fc',bh0,ab and a/h0 on shear capacity are more important.3?The contribution ratios of four comprehensive indexes using principal component analysis are called geometric dimension,span-depth ratio l0/h and longitudinal reinforcement ratio ?,concrete strength grade fc' and web reinforcement ratio ?v+?h,shear-span ratio a/h0 respectively.And their contribution ratios to shear strength are 31%,16%,13% and 9% in turn.The research provides theoretical references for shear calculation and design of deep flexural member.The statistical software SPSS is used to analyze and quantify the significant influence parameters on shear capacity of deep flexural members.These conclusions provide theoretical reference for the calculation and design on shear capacity of deep flexural members and also provide theoretical basis for further study on the shear behavior of deep flexural members.It is a great significance and value to the application and popularization of deep flexural members in engineering practice.