Study On Ultimate State Method And Reliability Of Recycled Concrete Beam At The Cross Section

With the rapid progress of urbanization in China, the processing of constructionwaste and deficiency of building materials have become the important problem whichaffects national economy and life. The recycled concrete and its structure not onlyabsorb a large amount of construction waste but also solve the shortage of buildingmaterials, which is the really friendly building material to environment. However, thecurrent design method of recycled concrete and its structure is not perfect and reliabilityanalysis of recycled concrete basic components needs to be solved especially, whichaffect the application of recycled concrete technology in actual engineering. Therecycled concrete technology can not be widely applied in actual engineering. Based onthe collection of domestic related research and combing the experimental date, thispaper analyzed the maximum crack width and deflection calculation method of thecross-section bearing capacity limit state and service ability limit state of recycledconcrete and put forward the related calculation formula. And then it analyzed thebearing capacity and normal use limit state by using the checking point method (JCmethod) and put forward the reliability evaluation and suggestion. The main work ofthis paper is as follows.(1) This paper stated and analyzed the bending test data of recycled concretebeams including our complete. Meanwhile it revised the calculation formula of themaximum crack width and defection of the normal section bending bearing capacity andnormal use in the ‘Code for design of concrete structures’(GB50010-2010). At last, thesuggested formula of recycled concrete beams was determined.(2) On the basis of suggested formula, this paper analyzed the reliability of limit state of bearing capacity of cross section and studied the influence of differentparameters on the reliability index. The results show that the reliability index conformedthe target reliability index in the ‘Unified Standard of Building Structures ReliabilityDesign’(GB50068-2001) of our country by computing the bearing capacity of crosssection of recycled concrete beam. It should be taken into account in the actual designbecause different parameters were different to reliability impact.(3) On the basis of suggested formula, this paper analyzed the maximum crack widthand deflection of limit state of recycled concrete beam normal use. The results showthat the reliability index conformed the target reliability index in the ‘Unified Standardof Building Structures Reliability Design’(GB50068-2001) of our country bycomputing the maximum crack width and deflection of limit state of recycled concretebeam normal use. It should be taken into account in the actual design because differentparameters were different to reliability impact.