Sub-regional and subsection linear control method during the construction of main cables strands for long-span suspension bridge

In order to realize the precise control of the strands under complicated temperature condition, the sub-regional and subsection control method was proposed based on the structural characteristics and topographic features of suspension bridge. The expressions of relations between sag and length, sag and span, and sag and temperature were deduced. Then the temperature field of the strands could be determined rapidly with the proposed method, and the adjusted length of the strands could be calculated with the deduced relations. The results show that the temperature of the main cables strands has characteristic of time-variation and randomness. According to the requirements of control precision and the material properties of the main cable, the equivalent temperature method is put forward and proved to be efficient. The adjustment coefficients of side-span are highly nonlinear and easy to be affected with the changes of sag, while the adjustment coefficients of mid-span are more stable relatively. Considering the topography under the bridge site, the suggested sub-regional and subsection linear control method is reasonable and feasible for the temperature monitoring of the main cable strands. The results of the linear control for the main cable strands proves to be highly efficient, high-precision and applicable. ©, 2015, Editorial Department of Journal of Chang'an University (Natural Science Edition). All right reserved.