Theoretical Analysis And Experimental Study Of Pre-stressed Composite Space Truss

Pre-stressed composite space truss is one of the new kind of space structure systems developed on the basis of prestress and space truss, which consists of steel and reinforced concrete. At present the study in this field is just being begun in our country. Therefore, in this paper static and dynamic performances of pre-stressed composite space truss associated with a practical engineering are studied, in addition, dynamic test on construction site and model experiment are done. Finally, we conclude this structure is well in stress and stiffness and dynamic characteristics.In this paper, firstly, composite finite element theory is described simply, static calculation of pre-stressed composite space truss is carried out with a nonlinear finite element program that programmed by author and the results are compared with those of ALGOR finite element program. The conclusion that nonlinear characteristics may not be considered in the analysis of pre-stressed composite space truss is presented.Secondly, natural frequencies of pre-stressed composite space truss are calculated with sub-space iterative method and all kinds of influencing factors are analysed. At the same time, simplified formula of fundamental period is obtained using ternary linear regression fundamentals.Next, based on the study above, a practical pre-stressed composite space truss is designed, which includes the detailed analysis of internal force of each element. Then, seismic analysis is carried out using two methods, one is mode shapes decomposed response spectrum method, and the other is time history method. Subsequently, tension recovery method is introduced and the controlling value of construction tension of pre-stressed cable is presented.At last, natural frequencies of practical pre-stressed composite space truss are tested with pulsatory method on construction site and its damping ratio is calculated, which gives another important data for engineering design. In addition, through the model experiment of pre-stressed rectangular square pyramid composite space truss, the correctness of characteristics of internal force and the feasibility of tension recovery method are proved.