【摘要】 箱形截面扭转中心位置是箱梁的重要几何参数,在薄壁箱梁桥扭转位移和内力计算中有重要作用。根据薄壁箱梁的结构特点,考虑实际工程中薄壁箱梁顶板和翼缘板不等厚度的实际情况,按薄壁箱形梁约束扭转理论,对桥梁工程中常用的箱形截面扭转中心位置计算公式进行理论推导。在箱形梁的底板中点虚开1个切口,把箱形梁截面上的剪力流分为开口截面剪力流和切口上的附加剪力流之和,利用这2种剪力流对切口引起的相对变形为零的条件,推导出计算单箱单室箱形截面扭转中心位置的显式表达式。数值算例表明:该公式正确,使用方便,可应用于箱梁结构分析与计算。更多还原

【Abstract】 The position of the torsion center is an important geometric parameter of box girder, and it plays a significant part in the calculation of torsion displacement and internal force for thin-walled box girder bridges.Based on the structural characteristics of thin-walled box girder structure, the computation equation of the torsion center position of box girder often used in bridge engineering is theoretically derived by using the theory of constrained torsion of thin-walled box girder, in which the thickness difference between the top plate and flange plate of box girder bridges is considered. The bottom of a box girder is cut in half in the middle hypothetically, and the shear flow is divided into two parts, i.e. the shear flow of open cross section and the additional shear flow in the open cross section. Based on the deformation compatibility condition, the explicit formula for the computation of the torsion center position is presented for single box girder bridges. Compared with numerical examples, it is showed that the formulae are accurate, and they can be used easily in the calculation and analysis of practical box girder structures.更多还原