Study On Calculation And Measurment Methods For Cable Forces Of Long-span Cable Net Structures

Calculation and measurement of cable force are the key points and knotty issues whendesigning and constructing the long-span cable net structures. According to the complicatedstructure and various forms with the large-span cable net structures, the cable force has atypical nonlinear characteristic during the construction process. Therefore the accuratecalculation of the cable force variations in construction simulation analysis, and the objectivemeasuring of the cable force variations in actual construction and long-term healthmonitoring stage, would be of great practical significance to guiding the design, constructionand normal operation of the large-span cable net structures.The thesis consists of three parts. The first part presents the nonlinear problems existingin the calculation of cable force, which is introducing several basic concepts of geometricnonlinearity and boundary nonlinearity, summarizing the usual calculation methods of cableforce; and then a new cable element is putted forward for the geometric nonlinearitysimulation, and the contact element is applied for the boundary nonlinearity simulation. Thesecond part shows the usual measurement methods of cable force, also discussing theadvantages and disadvantages of the existing measurement methods of cable force; after that,a new measurement method of cable force called Measurement Method of the Base Fixture isproposed, which is approved its practicability by experiment. The third part describes theeffect of temperature on cable force of the large-span cable net structures, by calculating thevariation of cable force with Shenzhen Bao’an Stadium at different temperatures, and makinga comparative analysis with the cable force data from the long-term health monitoringsystem.The studies of calculation and measurement of cable forces of the large-span cable netstructures have suggested that:(1) The new nonlinear cable element may accurately reflect the geometric nonlinearityproblem during the cable stretching construction.(2) Using Measurement Method of the Base Fixture may effectively measure the cableforce variations in the late stage of cable stretching construction and normal operation stageby reasons of its practicability. (3) The effect of annual temperature difference to the cable force of normal operationcould not be ignored.