Construction Process And Parameters Study On Pedestrian's Overpass With Beam String Structure

In the near future, Beam String Structure (BSS) is used in the long span space roof, but it was not used in the Pedestrian's Overpass before. The research is outspread based on the pedestrian's overpass between the main tower and the assistant tower of the Northeastern Grid Electricity Trade Center. In this dissertation the author bright forward a new space BSS, simulate the whole construction process, does the modes analysis, and sum up the rules for BSS under the influence of the parameters.Based on the research, the BSS is a suitable structure type for pedestrian's overpass, because it is lighter and having a biger span ability than concrete structrue, less inexpensive than steel structure, having a better outer plane stability than the traditional BSS and simple details.The construction process of the BSS pedestrian's overpass is divided into installing phase, pretension phase, and working phase. In the installing phase, the BSS needs temporary underprop. In the pretension phase, we should confirm critical tension when the steel beam disengage the temporary underprop.According to the modes analysis, for the composire slab, the natural frequenc is far from the walking frequency.According to parameters study, along with the a increase, the stiffness will decrease, and along with theκincrease, the stiffness will increase. For the temporary underprop hardly any influence to the whole stiffness, when we confirm the amount of the temporary bracket, we just need to consider the steel beam's stress and composire slab are not exceed the criterion.