RESEARCH ON ERROR OF A CABLE FORCE ESTIMATION METHOD FOR SPOKE STRUCTURAL ROOFS

Based on a cable force estimation method with static displacement for spoke structural roofs, the influence of displacement measurement error on the cable force estimation result is studied with numerical and theoretic analysis. Force estimation error is a monotone function of displacement measurement error. When the displacement is much larger than the measurement error, the function is almost linear, otherwise apparently nonlinear. With the same amplitude of displacement measurement error, the accuracy of cable force estimation varies remarkably due to load-measurement schemes. The error of force estimation result is small if the nodal displacement with respect to unit load is large. Several load-measurement schemes are compared, and the principle on making load-measurement scheme is to make structural geometric stiffness take primary effect. For spoke structures, half-span and quarter-span loads will achieve good force estimation results if the amount of loads is limited.