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汉江大桥焊接斜腿刚构梁长192米,而梁宽仅3.2米,结构轻巧,纤细,横向水平振动遂成为结构方案中的关键问题。本文叙述了振动模型试验及其结果,并论述试验数据与电算结果存在差异的原因。指出在计算时对于隅节点处的连接应正确假定,以及斜腿间横联的不同形式对振动频率影响极小。随后对实桥结构进行振动评价,并对强迫振动中共振扩大系数与非共振时水平最大振幅进行探讨。说明结构横向水平振动的性能较好是斜腿横向分叉所造成的。结构的另一重要问题是腹板稳定,文章的第三部分说明了腹板设计思路,提出了水平肋临界刚度的概念及其计算公式,对板块弹塑性临界应力给出了计算用表。15个模型试验表明,用此思路与方法设计的薄腹板,肋基本是刚性的,腹板稳定试验安全度比计算值约高6％。
Hanjiang River Bridge welded rigid beam beam 192 meters long, while the beam width of only 3.2 meters, the structure of lightweight, slender, horizontal horizontal vibration has become a key issue in the structural program. This paper describes the vibration model test and its results, and discusses the differences between the test data and the calculation results. It is pointed out that the connection to the corner node should be correctly assumed in calculation and the different forms of cross-links between the oblique legs have minimal influence on the vibration frequency. Then the vibration evaluation of the real bridge structure is carried out, and the maximum amplitude of resonance in forced vibration is discussed. The result shows that the performance of lateral vibration of horizontal structure is better caused by the lateral bifurcation of leg. The other important problem of the structure is the web stability. The third part of the article illustrates the web design concept and presents the concept and calculation formula of the critical stiffness of the horizontal rib. The computational table is given for the elastic-plastic critical stress of the panel. Fifteen model tests show that the ribs with thin webs designed by this method and method are basically rigid and the web stability test is about 6% higher than the calculated value.