Strength and Design of ThinーWalled Members with NonーSymmetric Open Section

在实际工程中，对称截面杆件在土木工程中得到了广泛的应用。只有少数几种非对称截面被用于次构件，利用它们在连接方面的优势。本文通过试验和数值计算，对异形截面柱的极限承载力和变形性能进行了分析，以合理设计异形截面柱，并对异形截面柱的可行性进行了验证。只要载荷通过截面的质心施加。如果荷载直接作用在腹板上，其强度约为对称截面柱的一半。通过弯曲试验发现，在加载点适当引入扭转或翘曲约束，其极限荷载可达到对称截面梁的数量级，并在此基础上对非对称截面梁及其组成的板梁的极限荷载和变形特性进行了数值模拟。试验结果表明，只要扭转和翘曲变形在边界和加载点受到一定程度的约束，这种板梁和异形梁的极限承载力可与普通对称截面板梁和异形梁的极限承载力同量级。此外，极限强度的性质的细长比参数显示出几乎相同的趋势的工字形截面梁。因此，这些非对称截面的构件可以在适当的约束下用于主构件。

In practice, the members with symmetric section have been commonly used in the civil engineering field. Only a few kinds of non-symmetric sections have been employed for the secondary members utilizing their advantage in connection. Here some experimental and numerical estimates of the ultimate strength and deformation properties of these non-symmetric section members have been carried out in order to rationalize the design and to examine the feasibility of these members.A set of tests of the shape columns reveals that the strength of the column becomes comparable to that of the normally-used symmetric section ones, provided that the load is applied through the centroid of the section. If the load is acting directly on the web plate, its strength becomes about half of the symmetric section columns. From the bending testings, the ultimate load can be of the same order of that of the symmetric section beams, if the torsional and/or warping constraints are introduced properly at the loading points.A numerical simulation based on these experimental observation is used to examine the ultimate load and deformation properties of the non-symmetric shape beams as well as the plate girder consisted of these nonsymmetric section members. As can be expected from the experiments, such a plate grider and ashape beam can have the same order of the ultimate strength as the normal symmetric section plate girders and shapes, provided that the torsional and warping deformation is to some extent constrained at the boundaries and the loading points, which can be easily expected from the practice. Furthermore the properties of the ultimate strength in terms of the slenderness ration parameter show almost the same tendency as those of I-section beams. Therefore these members with non-symmetric section can be used in the main members with appropriate constraints.