| With the sustained development of steel smelting and processing technology,high-strength steel with the yield strength in excess of 460 Mpa has been widely used in the field of structural engineering.Therefore,the adopted Standard for Design of High Strength Steel Structures(JGJ/T483-2020)for high-strength steel was enacted in 2020,but the design formula of the elastic critical moment of the two-span steel continuous beam is not specified when calculating the overall stability bearing capacity of the high-strength steel two-span continuous beam.At present,experimental research on the overall stability of Q460 high-strength steel welded I-section two-span continuous beam only focuses on the full symmetric section,and there is no experimental research on the monosymmetric continuous beam.Therefore,the Q460 high-strength steel monosymmetric welded I-section two-span continuous beam was experimented with and simulated to obtain the corrected formulation.The main research works are as follows:(1)The residual stress of the I-shaped section of Q460 high-strength steel was determined by the cross-sectional method,and the residual stress of the weld seam of three different shapes of "biaxial symmetry","upper flange thickening",and "upper flange widening" with three different shapes was obtained.Afterward,bending experiments were carried out,the results show that the overall stability bearing capacity of the twospan continuous beam with a strengthened upper flange is much higher than that of the two-span continuous beam with a full symmetric section.Besides,The overall buckling capacity of the two-span continuous beam can be increased by decreasing the span ratio.(2)All tested beams were simulated by ANSYS software,and the simulation results,including the test beam failure mode,mid-span load-displacement curve,and overall stable bearing capacity,were obtained and then compared with the experimental results,which were in agreement with the experimental results.Hence,by establishing the finite element model,a large number of influential factors were considered,such as different cross-sectional sizes,span ratios,different parts of the load points,different load points,and different load modes.Finally,the optimal solution for its overall stability was obtained.(3)According to the calculation method of the elastic critical moment of simply supported beam specified in the Standard for Design of Steel Structures(GB50017-2017),it was compared with the finite element result and fits the method.Based on the Standard for Design of High Strength Steel Structures(JGJ/T483-2020),the elastic ultimate bending moment value obtained by fitting was corrected,and compared with the measured value and FEM value,and the modified calculation formula in line with the specification was obtained. |
