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与传统梁相比,薄壁钢箱梁计算分析时必须考虑截面畸变效应和扭转效应对受力性能的影响,同时实际工程箱梁中设置的横隔板也直接影响梁的受力特性。基于广义坐标法原理和势能驻值原理,用MATLAB编制了薄壁钢箱梁结构考虑截面畸变效应和扭转效应影响的有限元计算程序,分析计算布置横隔板对薄壁钢箱梁受力性能的影响。通过数值计算,可知在扭转荷载作用下,横隔板间距越小,悬臂薄壁箱形梁固支端处翘曲正应力越大,远离支座的截面翘曲正应力趋于零。横隔板布置间距l与薄壁箱梁横截面最大尺寸H的比值小于2时,薄壁箱形梁的畸变正应力趋于零,可以忽略畸变效应的影响。布置横隔板对两端固支和两端简支箱形梁畸变正应力的影响规律一致,且比悬臂箱形梁的影响要大。最后引入畸变影响系数βdW,简化了薄壁箱形梁纵向正应力的计算方法。
Compared with the traditional beam, the calculation and analysis of the thin-walled steel box girder must consider the effect of cross-section distortion and torsional effect on the force performance, and the diaphragm in the actual engineering box girder also directly affects the force characteristics of the beam. Based on the principle of generalized coordinate method and the principle of potential energy value, the finite element calculation program considering the effect of section distortion and torsional effect of thin-walled steel box girder is developed by MATLAB, and the influence of layout diaphragms on the mechanical performance of thin-walled steel box girder is analyzed and calculated. Numerical calculation shows that under the torsional load, the smaller the spacing of the diaphragm, the greater the positive warpage of the cantilevered thin-walled box girder, and the normal stress of the warpage away from the bearing tends to zero. When the ratio of the distance l between the diaphragm and the maximum dimension H of the thin-walled box girder is smaller than 2, the normal stress of distortion of the thin-walled box girder tends to be zero and the influence of the distortion effect can be neglected. The influence of layout diaphragms on the normal stress of the two ends fixed beams and the box beams with simple ends at both ends is the same, and the influence is greater than that of the cantilever box beams. Finally, the influence coefficient βdW of distortion is introduced to simplify the calculation method of the longitudinal normal stress of thin-walled box girder.