梁式桥桥型方案比选分析

Analysis on Alternative Comparison and Selection for Girder-type Bridges

大型桥梁在方案设计阶段的失误将造成巨大损失,这种损失在随后的详细设计阶段和施工阶段以及运营阶段都是难以弥补的。因此,有必要对桥梁方案设计的原则进行探讨。提出经济跨径的概念,不仅揭示了多跨桥梁孔跨布置的经济性原则,而且还可以清楚地说明世界桥梁界面临的两大挑战即桥梁大跨度技术与深水基础技术之间的关系。通过对简支梁桥与等截面连续梁桥,连续梁桥与连续刚构桥方案的适用性进行比较,探讨了梁式桥方案设计应遵循的基本原则,还论述了悬臂梁桥与T形刚构桥两种梁式桥被淘汰的原因。

The alternative selection of a bridge decides its performance in whole. The misplay in alternative selection of a great bridge project would result tremendous losing, which could not be covered during the subsequent detail design, construction, and operation stages. Therefore, it is necessary to discuss the basic principles of alternative selection for bridges. The concept of economical span length was firstly proposed, which reveal the economical principle for the layout of span number and length to the multi-span bridges, and also can explain the relationship between the technique enlarging the span lengths and that building the deepwater foundations. Some basic principles which should be followed in the alternative selection for girder bridges were presented through the comparisons of simple-supported girder and constant depth continuous girder bridges, and continuous girder and continuous rigid-frame bridges. Moreover, the reasons why cantilever and T-shaped rigid frame bridges had been replaced were discussed.