Study On Earthquake Response Of Long-span Prestressed Conic Arch Shell Steel Roof

In accordance with the demand of increasingly large space for industrial plants,transportation buildings and public buildings, a variety of new-style space structureshave achieved remarkable development. Among the most promising ones is thePrestressed Space Structure, which combines the advantages of the prestressingtechnique and modern space structures. While, the appearance of novel roof structuralsystems and the damage of steel structures in recect earthquakes make people awareof the importance of seismic analysis of long-span roof structures.Some times the long-span roof is not directly situated on the ground but on thebearing system, for instance, a steel roof on the concrete structure. In this case, themutual action between the roof and the beating system occurs, which includesnon-classical damping and dynamic interaction. Further research needs to be carriedout both theoretically and practically on the mutual action of the roof-beating system.And it is necessary to give a reasonable method for the seismic analysis of this kindof roof structure.Based on the steel roof project of Shanghai South Railway Station, the mutual actionof long-span prestressed conic arch shell steel roof on concrete bearing system isstudied in this dissertation. On the basis of domestic and overseas research findingsabout non-classical damping system, the author deduced the formulae of potentialenergy of members such as beam, column, bar, cable, masonry infill wall andreinforced concrete shear wall. And by utilizing the potential energy weightedprinciple, a practical method to calculate the equivalent composite damping ratio ofthis kind of roof-bearing system is put forward. According to the method proposed inthe dissertation, a range of equivalent composite damping ratio by 0.02～0.03 for thelong-span prestressed conic arch shell steel roof on concrete bearing system isachieved. The author studied the dynamic interaction between the long-span steel roof and itsconcrete bearing system by means of harmonic analysis and time history analysis.And based on the research of the story acceleration spectrum, a new practical methodthat use story acceleration spectrum to calculate the seismic response of the steel roofis proposed and proved feasible in the following research. The error of the presentway commonly used in seismic analysis of the steel roof is studied. Result shows thatthe 'story spectrum method' presented in this dissertation gives high precision.Finally, the seismic response of the long-span roof structure of Shanghai SouthRailway Station under multiple earthquake excitations is analysed, and the initialstress of cables studied. Result shows that the cable system performs well underfrequently occurred and seldomly occurred earquake.