With the better torsion performance of box section beams and beam - columns than members with open cross - section and the progress of the manufacturing technology of box section members , the box section members find wider and wider application , especially in high rise buildings 箱形截面梁与梁柱由于较其它形式的截面具有较好的两个主轴方向抗弯刚度和抗扭刚度，随着钢结构的不断发展，箱形构件制作工艺的完善和日趋成熟，箱形截面构件的应用越来越广，尤其是在多高层建筑中。
First , the stability of box section beams under pure bending is studied based on two different torsion theories on members with closed cross - section by umansky and gjelsvik in the elastic phase , and the critical moments are obtained . comparisons show that these two different theories give nearly the same critical moments 文章首先对箱形梁进行研究，分别基于umansky约束扭转理论和gielsvik约束扭转理论推导了箱形梁在纯弯作用下的弹性临界弯矩，并进行了比较，发现基于gielsvik约束扭转理论的临界弯矩具有较好的精度且形式简单。
The effect of different sizes of sections , modes and values of residual stresses are studied . through the analysis , the conclusion is arrived at that the universal slenderness ratio should be used to better correlate the stability of box section beams with the member length instead of the out - of - plane slenderness , and the stability coefficient is taken to be 1 . 0 for practical used box girder . then , the elastic critical loads of box section beam - columns are obtained based on the gjelsvik theory , and the relationship between axis force p and moment m is given 最后，运用ansys通用有限元程序的beam189单元，引入初弯曲和残余应力的影响，用考虑几何和材料双重非线性的有限元求解格式求得箱形柱在不同轴力和弯矩比例作用下的弹塑性极限承载力，通过对十几个不同截面尺寸构件在不同长细比下的承载力计算，发现在轴力p远大于弯矩m时，构件将是平面外失稳控制，而当轴力p远小于弯矩m时，构件则以平面内失稳为主。
The bridge with box section possesses a better construction characteristics such as higher torsional rigidity and the better force property . 6 . the accumulation of the measured impact coefficient can promote the adoption of the design impact coefficient , which is the basis of the safe run and test of the bridge 武汉理工大学硕卜学位论文5 、箱形截面梁具有良好的结构性能，抗扭刚度大、受力性能合理，预应力连续箱梁桥结合了预应力连续梁桥和箱形梁的优点，较好地发挥了材料和结构性能的优势。
