Theoretical Analysis And Experimental Study Of Load-relieving Large Span Beam String Structures

Load-relieving system is a new idea in the engineering design. Aiming at the different designreliability, the load-relieving structure can adjust its structure form automatically under the destroyed loads,which can change shock load influence on the structure, avoiding the probable structure destroy. It is quitemeaningful to introduce the load-relieving idea into large span beam string structure, search the simple andefficient load-relieving device and calculation method of sliding cable and support the application ofload-relieving system in engineering structure.In this paper, we summarized the study status home and abroad, studied the structure form ofload-relieving device and proposed the iterative calculation method of sliding cables in load-relieving beamstring structure. Load-relieving device is the key component of load-relieving structure, so the structureform innovation of load-relieving device is very important for load-relieving system. In this paper, throughmodifying the pulley, we construct a new load-relieving device which enriches the types of load-relievingdevice. For the calculation of sliding cables in load-relieving structure, we propose the iterative calculationmethod which use the temperature strain to simulate the sliding of cable segment, changing the slidingcable problems into non-sliding cable problems, with clear concept, good reliability and highaccuracy.Besides, through introducing the new load-relieving device into the beam string structures, we putforward three load-relieving beam string structures which are load-relieving truss, load-relieving beamstring structure and load-relieving cantilever string structure, studied their mechanical property andapplication situation. Finally, we carried out a static trial on the load-relieving beam string structure.In this paper, we studied the above mentioned load-relieving beam string structures and foundthat the cable can keep tensioned all the time in the beam string structures with the help of load-relievingdevice. The constant prestressing force can enhance the stiffness of structure and the resisting destroy loadability. However, compared with the normal beam string structures, the load-relieving structures have alarger nodal displacement but smaller member internal force. Besides, we studied the load-relieving beamstring structure through theoretical analysis and experiment research. After the comparison of nodaldisplacement and member internal force, we find that the experiment results almost agree with thetheoretical analysis results. Through the experiment, we realize the mechanics property and mechanism ofaction intuitively.