中文摘要：

基于莫氏假定，考虑到箱形截面顶、底板几何尺寸对开裂弯矩的影响，推导了钢筋混凝土箱形截面受弯构件纵向受拉钢筋最小配筋量计算公式，该公式同样适用于矩形、I形、T形等常见类型截面．对一单箱单室钢筋混凝土箱梁最小配筋量的计算表明，现行公路桥规对钢筋混凝土箱形截面受弯构件最小配筋量的规定偏低．最后对土木工程中常见的箱形截面受弯构件，提出计算箱形截面受弯构件纵向受拉钢筋最小配筋量的简化计算公式．

英文摘要：

Taken into account of size effect of top and bottom slabs on cracking moment of reinforced concrete box girder, an evaluation formula for minimum amount of reinforcing steel in bent component in longitudinal tension was derived based on the assumption of Мурашев. This formula could similarly be applied to the components with such sections as rectangular, I-shaped, T-shaped, etc. The calculation result of minimum amount reinforcing steel for single-box single-cell girder showed that the corresponding minimum amount stipulated by current code of highway bridges was partially low. Finally, a simplified formula for this kind of evaluation was presented.