Crack Control Method Based On Test For Concrete Flexural Members

In the structural serviceability limit states design,the crack control of member is a very important content.At present,most of the methods used for crack control in the world are approximate probabilistic limit state design methods based on structural reliability theory,mainly including the partial safety factor method and the design value method,which are both based on structural analysis.In order to control the member performance more effectively,a new design method has emerged in the standards of various countries,that is,the design method based on tests.The method uses structural test as an intermediate link,collects samples of member performance in the test,and directly determines the design value of component performance through small sample inference method,which has outstanding demonstration and pertinence,and makes significant effect for the design of large numbers of similar members,complex structures and new structures.But so far,the application of the design method based on test is limited to the ultimate limit states,and there is no corresponding design method for the serviceability limit states.This dissertation takes concrete flexural members as an example,introduces the design method based on test into crack control,and is devoted to establish a crack control method based on test for concrete flexural members.The core content of the method is to infer the design value of the member cracking performance based on the test results.The main research work includes:(1)Refer to the application of the design method based on test in member resistance inference,the basic crack control method based on test for concrete flexural members is initially established.(2)According to the design requirements,through probability analysis,the probability characteristics of cracking performance of concrete flexural members under test conditions were revealed,including probability distribution type,coefficient of variation and guarantee rate of design value.(3)Aiming at the actual situation with limited number of samples in the test,a small sample inference method for design value of cracking performance of concrete flexural members is established.(4)On the basis of the above research work,a complete crack control method based on test for concrete flexural members is finally proposed,and relevant design suggestions were given.The research results not only theoretically establish a crack control method based on test for concrete flexural members,but also fill the gaps in the design method based on test for the serviceability limit states,and also help to improve the effect of crack control of concrete flexural members in engineering applications.