Determining Of Reasonable Design States And Construction Controlling Of Cable-Stayed Bridges

There are many research results in determining the finished state and construction states and in construction controlling of cable梥tayed bridges. However there are still a lot of problems in the application, especially without an integrated method. Having done many studies in these three aspects throughout more than ten cable梥tayed bridges, the author has come up with an integrated method, and a visualization design of computer program. l.An optimization method for determining the reasonable finished state of cable梥tayed bridges by aiming to restrict the stress of the main beam is introduced. The method has four steps. a) Ascertain the reasonable prestressing Quantity, under the controlling conditions according to the most and the least stresses of the top and below edges of the beam controlling section. b) Collocate the prestress according to the reasonable prestress and other design demands and then ascertain the dead moment feasible field of the main beam of the finished bridge. c) Taking the cable tensile forces of the finished bridge as variables, We can form a optimization model which is subjected to the restriction considering the requirements of uniform of the cable forces, the resistance of the side and assistant piers, the bending of the towers 慳nd the dead moment feasible field of the beam. d) Make out the optimization model and then attain a reasonable finished state. 2.A forward梚teration method for determining the reasonable construc- tion state of cable梥tayed bridges is introduced. The method is described as the following. A finished bridge state is gotten with the forward* calculation presuming the controlling cable tensing forces. We can modify the controlling cable tensing forces to minimize the difference values between the result and the predetermined value of the resonable finished bridge by the least squares method. Iterate the aforesaid procedure until the value is constringed. The method only requires forward梒alculation, even it can minimize the effect of no梒losure by the least squares method. Advantages of this method includes four points. l)It simplifies the input of calculating data greatly because it only need to do forward* analysis, while other methods always needs to do backward梐nalysis.2)It avoids the problem of no梒losure. Although the calculation has a difference compared with the reasonable finished bridge state, the difference is so puny by optimization (least squares method) that the result can meet engineering requirement, 3)Letting the controlling parameter be expectative value, the two processes of determining the reasonable finished state and 2 the construction state of bridges can be done in one process. 4) The initial value of the controlling cable tensing forces in the forward* iteration is optional to presume. 3.A parameter model of construction controlling of cable梥tayed bridges is established. The object of the cable bridge constru:tion controlling is achieved by adjustting the controlling variables (cable tensile forces and the form setting levels) to assure the finished bridge state optimal through recognizing and predicting errors of parameters. The thought of this method contains the following: Ascertain the influencing parameter in light of the difference between the measuring result and the corresponding theoretic value of the status variable (the reference point displacement. cable forces * stress and strain of the referenc...