The paper takes a cable-stayed bridge with couple tower,couple cable,three-span prestressed concrete beam and steel truss composite beam for example,analyzes and compares various factors that affect the vertical rigidity of composite beam cable-stayed bridge of double line railway.

The present situation of vertical rigidity tor the existing railway bridges under the action of Zhong-live load as stipulated in the railway design specifications in China and the proportional relationship between various load working conditions and Zhong-live load are analyzed.

The results show that as the vertical rigidity index of bridge exceeds allowance of the design specification,the running quality of vehicle and dynamical behaviour of the bridge are still in good condition.

A Simple method for computing vertical stiffness of rubber bearings;

Using fatigue machine designed by authors, adopting China rubber bearings of 160 mm diameter,this paper studied the changes of the vertical deformation and vertical stiffness of the rubber bearings by vertical fatigue load test of 100 thousands repetition, studied the durability property of rubber bearings.

It is considered with the offset vertical stiffness of bearing isolation in analyzing the earthquake response for the isolated tower structure.

By inducing the concept of interaction coefficient, a method was proposed to estimate the equivalent dynamic stiffness matrix of the structure on the layered site.

Using the model,we analyze the effects of the two springs′ stiffness on the vertical load,vertical displacement,vertical equivalent stiffness and natural vibrational frequency of the seat suspension system during its stroke.

Based on finite element analysis of high-rise buildings whose transfer stories are set at the first story and act as open floor,this paper discusses three types lateral stiffness control parameters of transfer story: story lateral stiffness ratio,equivalent shear stiffness ratio and equivalent lateral stiffness ratio.