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Test And Analysis On Shear Behavior Of Precast Prestressed Concrete Double Tees With Partial Mesh Reinforcement

Posted on:2020-12-30Degree:MasterType:Thesis
Country:ChinaCandidate:Z H ZhaoFull Text:PDF
GTID:2392330599953645Subject:engineering
Abstract/Summary:PDF Full Text Request
The application of prestressed precast concrete double tees in precast concrete buildings is more and more extensive due to its excellent mechanical property and economic advantages.But as for double tees with partial mesh reinforcement,the web is inverted trapezoidal and the bottom width of web is relatively narrow.To meet the fireproof requirements for concrete cover,the reinforcement arrangement is that two prestressed tendons in each row at the upper part of the web and one prestressed tendon in each row at the lower part of the web.As a result,the mesh reinforcement placed in the middle of the web as shear reinforcement can only reach the bottom part of the area in which the reinforcement arrangement is two tendons in each row,this means that there is no mesh reinforcement for shear within the range that the reinforcement arrangement is one prestressed tendon per row.Its shear strength and mechanical behavior need further investigation and research.Eleven specimens under different ratios of mesh reinforcement height and member height,different shear span ratios are tested for their shear performance.Based on the analysis of shear capacity and failure mode of members,the feasibility of the layout of prestressed tendons and mesh reinforcement for this kind of double tees is studied,and the most suitable method for the calculation of the shear capacity for double tees with partial mesh reinforcement is selected.The influence of different prestressed tendon numbers,different spacings of shear bars and different heights of member on the difference between the shear capacity calculated using the proposed formula and the normative formula is analyzed.The range with mesh reinforcement as shear reinforcement for double tees is studied.The main conclusions are as follows:(1)Double tees members with partial mesh reinforcement have shown good shear performance in the test.There is no premature bond crack around the prestressed tendons and premature failure after cracking,which proves the feasibility of double tees with partial mesh reinforcement(2)Through the study of the“effective height”for the calculation of the shear resistance contribution of the stirrup in the normative formula,three calculation methods including the normative formula are obtained.The effective height expression of hd is proposed.Based on theoretical analysis and experimental results,all of three methods have a good safety reserve,and the method which replaces h0 with hd for the calculation of the shear resistance contribution of the stirrup is theoretically most suitable for double tees with partial mesh reinforcement.(3)Based on the test results and foreign references,it is considered that when the shear force is less than one-half of the concrete shear contribution,mesh reinforcement for shear can be omitted in this range.
Keywords/Search Tags:Double Tees with Partial Mesh Reinforcement, Shear Behaviour, Shear Reinforcement, Range with Mesh Reinforcement for Shear
PDF Full Text Request
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