预应力网壳结构中加劲板式橡胶支座的计算模型及设计

Mechanical Model and Design Method of Rubber Bearing in Prestressed Reticulated Shells

浅网壳施加预应力的目的，一是调整网壳内力分布，控制网壳变形；二是保证网壳在正常使用阶段基本成自平衡系，减小网壳在支座处的巨大水平推力，使下部支承结构始终处于小偏心受压状态，充分发挥支承结构的承重作用。这类结构的支座选型十分重要。分析表明采用综合力学性能好的加劲板式橡胶支座较为合理。本文介绍了一种预应力网壳的加劲板式橡胶支座模型设计方法。采用这种方法设计的支座能使网壳较充分地利用预应力，施工期间下部支承所受的最大水平外力只不过是橡胶垫与预埋板之间产生的最大静摩擦力而已；在正常使用阶段则能保证预应力网壳本身基本构成力自平衡系，并有效地将网壳与支承结构连成整体。

There are two main purposes of prestressing a long/median span shallow reticulated shell along its boundary edges at an appropriate force,one being to adjust the distribution of bar forces and control the deformation of the shell ,the other being to make the shell a force-balance body on horizontal plan approximately at service stage by reducing the thrusts at the shell supports so as to keep the supporting structure under the shell always working under the compression state of small eccentricity in order to make the best of suppporting function of the supporting structure.For such shell, the selection of bearing is rather important.Analysis shows that it is rational to employ a special kind of rubber bearing.This paper puts forward a mechanical model of friction slide contact element and a corresponding design method for the bearing.In the structure designed by the method at the stage of construction the maximal horizontal thrust at a bearing is only the peak static friction force between the rubber and the embedded plate and in the period of normal use, the bearing can well perform the functions of fastening the shell to the supporting structure and making the shell a force-balance body on horizontal plan appoximately.