中文摘要：

为研究交叉索对结构刚度的影响程度及规律,提出多塔斜拉桥设置跨中交叉索的 2种方案,通过改变跨中交叉索对数,共建立 11个对比方案进行有限元分析,得出在不平衡荷载作用下,设置跨中交叉索使得结构内力、变形均大幅减小.为给出基于双指标的交叉索比例合理范围,通过对基于结构刚度的交叉索效率、基于全桥用索量的交叉索经济性进行分析,并结合现行规范与实桥经验数据,确定 2指标的限值,将设置不同比例交叉索的多塔斜拉桥划分为 3个区域,各区域内斜拉桥的刚度、用索量各有差异,由分析确定交叉索斜拉桥的优选方案.研究结果表明：最优方案为采用方案 2方法设置交叉索,且交叉索比例合理范围为 15%~35%,若必须采用方案1,则交叉索比例应控制在 16%以内以保证结构经济性.

英文摘要：

In order to study the influence degree and regularities of structural rigidity on crossed cables,two kindsof setting schemes of crossed cables were presented. The finite element analysis of 11 contrast schemes wasestablished by changing the quantity of the crossed cables. The results show that the internal force anddeformation of structure are significantly reduced. In order to give a reasonable range of the proportion of crossedcables based on double indexes, this paper analyzed the efficiency of the cables for structure stiffness and theeconomy of the cables for the cable quantity. And combined with the existing specification and the data of existingbridges, the limit values of two indexes were determined. The cable-stayed bridge with different proportions ofcrossed cables were divided into three regions. In each region, there was a difference between the stiffness ofstructure and the amount of cables. From this we can determine the optimal scheme. The results show that theoptimal scheme is the crossed cables setted by adopting the method of scheme 2, and the reasonable range of theproportion of crossed cables is 15%~35%. If we have to use the scheme 1, we must control the reasonable rangeof the proportion of crossed cables within 16% so as to ensure the economic of structure.