Formula Research Of How To Replace The Curved Girder Bridge By The Straight Bridge And Comprehensive Analysis Of Multi—factor

Prestressed concrete continuous curved girder bridge with small footprint, linear smooth and elegant, vivid conception and so on advantages in overpass, highway and viaduct is widely used in practical projects. However because of radius of curvature curved girder bridge results eccentric of structural volume center of gravity, leads to the coupling effect of bending and torsion, and makes its mechanical properties and deformation more complex than straight bridge.The absence of reliable theoretical analysis and perfect technical specifications, in the construction and operations curved girder bridge appears so many times consolidation Pier Body cracking, end of the beam warping, beam"climb shift"to the outside corner, beam and bearing voiding(that is"bearing separation)bridge collapsing and so on bridge diseases. The topic makes Shenzhen Wu tong Mountain Interchange Project as the background, analysis of formula of how to replace the curved girder bridge by the straight bridge and comprehensive analysis of multi-factor. The meaning of replacing the curved girder bridge by the straight bridge is that curved girder bridge will be unfolded, design and calculate in accordance with straight bridge that has the equivalent centerline length. In this text, I analysis the criterion of replacing the curved girder bridge by the straight bridge in order to simplify the design process of curved girder bridge and provide a discriminant formula of replacing the curved girder by the straight bridge. In addition, in the comprehensive analysis of multi-factor I combine the load which curved girder brider is often taken in order to provider a theoretical basis of values of design load in the design process and a basis of specification formulating and improvement for curved girder bridge. The contents and main results of this study as followings:(1) This topic firstly analysis the influences that the four geometric parameters to the mechanical properties and deformation of curved girder bridge. The method of replacing the curved girder by the straight bridge is finding a critical radius Rcritical. When the design radius is less than Rcritical, it can not replace the curved girder by the straight bridge. When the design radius is greater than or equal to Rcritical, it can replace the curved girder by the straight bridge.(2) Under the risk control rate of the maximum principal stress is equal to 5% and 10%, I obtain the critical radius with the known bridge width, bridge length and high of bridge piers, then numerical fit formula for replacing the curved girder bridge by the straight bridge. Above formulas only fit to three-span curved girder bridge. Finally I verify the formula of this topic compared with the authoritative research results of replacing the curved girder bridge by the straight bridge. The formula under 5% the risk control rate apply well to single-span and three-span curved girder bridge. The formula under 10% the risk control rate do not apply to single-span curved girder bridge but apply well to three–span curved girder bridge.(3) In the comprehensive anysis of multy-factor, I combine the load which curved girder bridge is often taken, then obtain the worst load combination and a ratio that the mechanical effect of a alone load dividing mechanical effect of the worst load combination. When according to the design of basic combination of the carrying capacity ultimate state, changing the radius, the change of peak torque generated by vehicles load is less than the change of peak torque generated by other loads; Change the pre-eccentric pier, the change of peak torque generated by gravity + additional torque is less than the change of peak torque generated by other loads. When according to the design of the design of short–term effect combination of the normal use limit state, changing the radius, the change of peak torque generated by pre-tension is less than the change of peak torque generated by other loads; Change the pre-eccentric pier, the change of peak torque generated by gravity + additional torque is less than the change of peak torque generated by other loads.