Research On Prestressed Concrete Structure Design Of Harbin West Railway Station

Harbin west railway station is one of the major construction projects of in Heilongjiang Province during"the eleventh five-year plans". It is the second largest railway passenger station and would be one of the most important transport hubs in Northeast China. The station consists of south and north station buildings, a central high elevated waiting room and a railway floor. The main structure of station is concrete frame, and the roof is curved steel structure. For its large span and huge weight, post-tensioned bonded prestressed concrete technology is employed in structural design to ensure the deformation and cracks control of the structure can satisfy the requirement of serviceability limit state.The south and north station buildings and the waiting room are large in size and super long in length and the force on the railway floor is large and complicated due to train loads. The deformation and crack control would not be satisfied if full-length prestressed strands were placed in the frame beams since they would cause great prestressing loss due to friction. In this design, the structures of the south and north station buildings and the waiting room are divided into several parts through the establishing post-poured belts in the short-span directions so that the span of prestressed concrete beams are in a moderate range. The prestressing loss due to friction is reduced and the design becomes reasonable and economical. For the prestressed concrete beams of the railway floor, three improved reinforcement schemes are proposed to reduce the prestressing loss due to friction, including reinforcements by straight bonded strands, the hybrid reinforcement by both bonded and unbonded strands and the scheme of sectional stretching of the strands. Comparative analysis shows that the latter two schemes not only reduce prestressing loss but also make the design satisfy the requirement of serviceability limit state.For seismic design of prestressed concrete structures, the ratio of prestressing strength and the relative height of equivalent compression zone at the end of the frame beam are the two significant parameters which should satisfy the requirement of codes concerned. Crack width control method by improved nominal tensile stress is applied to determine the area of prestressed steel bar and non-prestressed steel bar. Under the premise that total reicforcement ratio don't exceed the limit, the ratio of prestressing strength can satisfy the code's demand because it is taken as a bound condition in this method. Keeping the dimendions of the beam cross sections constant, certain amount of compression reinforcement is placed in compression zones of beam ends so that relative heights of equivalent compression zones can satisfy the code's requirement.The design philosophy and method mentioned in this paper has efficiently solved the technical problem in practice, and it will provide valuable reference for design and construction of the similar projects.