Research On The Main Cable Shape Of Construction Process For Self-anchored Suspension Bridge With Multi-tower

Suspension bridge has a long history in China, while, it is a kind of modern bridge. As far as the ancient times, people knew well about the earth-anchored suspension bridge. In fact, the self-anchored suspension bridge with the main cable anchored in their own stiffening girder is also an important type. Although research on this subject has just been carried out in our country, we have stridden an innovative step in practice. The thesis makes research on some key problems, such as the shape of the main cable and other issues in different construction stages of the first self-anchored suspension bridge with multi-tower - Luozhou Bridge under construction in the world.It makes comparisons among three analysis theories of self-anchored suspension bridge,namely elastic theory, deflection theory, and the nonlinear limited displacement theory in the paper. Considering that the self-anchored suspension bridge with multi-tower shows obviously nonlinear characteristics in the construction stages, the paper does some theoretical analysis on the cable, the stiffening girder and the saddle based on the nonlinear theory, and then compares the parabola theory with the segmental catenary theory which can be used to calculate the main cable shape, and then proposes a numerical analysis method which is suitable for the self-anchored suspension bridge with multi-tower to calculate the main cable shape depending on the segmental catenary theory.Based on the numerical analysis, we build up the finite element model of the multi-tower self-anchored suspension bridge with the ANSYS software, adopting the backward analysis method and the forward analysis method, In the backward analysis method,we take the main cable shape of the finished bridge state, the first period dead load and the cable-finished stage into account. In the forward analysis method, we make analysis on the ideal hanger installation force to analyze the process by stages, and focus on comparing the inner force and deformation characteristics of the main components of the bridge in each ideal state, which don’t take the sequence of the hanger installation into consideration. At last, we get the closure precision calculated in two methods, and the law by which the main cable shape of the self-anchored suspension bridge with multi-tower changes, in order to make preparations for complicated construction simulation of the sequence of the hanger installation.It also makes research on the construction process monitoring and uses the monitoring data to verify the weak interference of main cable displacement and the near influence of hanger installation force manifested in the hanger installation process. Besides, we bring up two different hanger installation optimization methods based on the principle of the hanger installation scheme, and then testify the rationality of the selected construction scheme. Above that, we build up the precise finite element model of the further construction and compare the calculation results with the construction monitoring data, make analysis on the linear change law of the main cable shape, the main tower and the main beam in the hanger installation process of the self-anchored suspension bridge with multi-tower, and the corresponding construction control methods.We study the impact of the rise-span ratio of the main cable, the stiffness of the cable and other design parameters to the structural characteristics of the self-anchored suspension bridge with multi-tower, and the change of the main cable shape with the variation of temperature and boundary conditions in the construction process. Comparisons have been made between the self-anchored suspension bridge with multi-tower and the self-anchored single tower suspension bridge, great importance is attached to analyzing the effect of the interaction between the main tower and the main cable on the main cable shape. Finally the uniqueness of the bridge-type layout and the construction process of the self-anchored suspension bridge with multi-tower is highlighted.