| With the development of China’s construction industry technology,the advantages of high-strength steel bars have received more and more attention from people.The country is now vigorously promoting the application of high-strength steel bars.Compared with500 MPa reinforced concrete structure,there are few studies on 600 MPa reinforced concrete structure.In order to promote the application of 600 MPa steel in concrete structure,it is necessary to carry out relevant tests of its performance.This thesis concretes on 7 reinforced concrete beams with 600 MPa steel bars and 3reinforced concrete beams with 400 MPa steel bars,which are subjected to bending tests under the concentrated load.The stress performance of the test beam,the process of crack development and the failure characteristics were studied experimentally.The applicability of the formula for calculating cracks and deflection of concrete structure design code(GB50010-2010)is studied.The results show that the bending performance of 600 MPa grade reinforced concrete beams is basically the same as that of ordinary reinforced concrete beams.Under those normal service limit conditions,the maximum crack width and deflection can be checked by the formula in according to the "Code for Design of Concrete Structures"(GB 50010-2010).The deflection of the 600 MPa grade reinforced concrete beam can meet the requirements of the GB 50010-2010 deflection limit.Through this experiment and collecting a large amount of data,305 high strength reinforced concrete beam test data are calculated to calculate the uncertainty coefficient of the fracture calculation mode 0.89.The reliability of the formula for maximum crack width of bending members in(GB 50010-2010)of "Specification for concrete structure design" is analyzed and calculated by JC.The mean value of crack reliability index of secondary test beam is 0.463.According to the test data and the collection of a large number of high-strength reinforced concrete beams at home and abroad a total of 305,the reliable index mean of high strength reinforced concrete beam cracks is 0.6721.The reliability index of crack width of normal use limit state conforms to the reliability Index range 0～1.5. |
