Wind-Resistant And Stability Of Compressive Chord Study On Long Span Rond Streel Truss

The large-span roof has already extensive applied to various kinds of large-scale public buildings.On one hand because this kind of structure tends to be more flexible and light, so we muse develop corresponding theory, in order to the engineers can estimate the wind loads more precision. On the other hand in the design code of steel structure in our country, there are only specifications about effective lengths of compressed members in plane truss; the proposals of compressed members in tubular truss are not specified. But reasonable effective length of compressed chords and braces are necessary and important to make sure the structure security and to make full use of the mechanical property of the material.This text combines wind-tunnel testing and structural design of long span roof of rail way station of Bei Dai He city, has introduced the characteristic of atmospheric boundary layer at first, basic wind pressure and method of how to determine the shape coefficient, Open-type large-span roof structure of the wind tunnel test method, compared the difference of synchronous and asynchronous measurement, given the test results and advised how to estimate the wind load shape coefficient on Special-shaped structure, discussed how the surrounding environment affect wind load shape coefficient, at last I investigated the characteristic of wind pressures on long span roofs. The aim is to provide certain actual reference meanings to other actual projects.Then the article has analyzed the principle of the Steel stability, described my understanding of the relevant clause of the design code of steel structure in our country, summarized the questions that needed to pay attention to, and introduced the effective lengths of compressed members in tubule truss and hypothesis and theoretical foundation. Finally I adopt software of SAP2000 to analyze the tubular truss, analyzed and compared every influential factor about effective lengths of compressed members in tubular truss, and provided the coefficient proposing value of effective length.