The Cable Tension Test And Theory Research Of Beam String Structure Based On Half-wave Method

In recent years, beam string structure has been a new structure. It has been widely applied to current buildings because of its good structural stress, tensile properties of high strength, beautiful shape and convenient in installation. Lasso is an important component of beam string structure to bear force, the battle of stress state of lasso is related to the safety and normal operation of whole structure during its working. The precision and practicability of test of cable force directly affects healthy application of large span beam string structure, so it is important practical significance to make an accurate measure of cable force when it is working.The frequency method is the main method of cable tension testing, but for the multi pole beam string structural, Cable connection conditions and environmental factors make an impact on the measurement accuracy of multi pole beam string structural. Facing the problem of the complexity of cable segment's constraint and identification accuracy of cable force for of beam string structure, a new method named half-wave method is used to identify cable tension. Half-wave method is a kind of method and based on the frequency method. The high-order mode recognition is the key of half-wave method and calculate the cable force by high order.First of all, it is proved that test of cable tension can be carried out in the bottom chord's tension cable of beam string structure by using half-wave method is feasibility through experimental study of beam string structure model. Sensors were deployed on the intermediate span of the scale model of the two struts beam string structure and half wavelength of high order modes is measured by using artificial methods to motivate local cable vibration. A simply supported single cable model is used to identify cable tension of the whole beam string structure's tension cable, the more accurate cable tension can be obtained by measuring higher order modes. it is showed by experimental results that it is feasible for beam string structure's tension cable to use the half-wave method to carry out test of cable tension and more accurate result of cable tension can be obtained, when measured model of four or more order.Secondly, According to finite element model established of the yellow river estuary testing hall, the prestress of cables is applied by applying strain, mode analysis of a cross is made, cable tension is calculated by half wavelength of high modes and corresponding frequencies. The results of finite element analysis show that, cable tension is close to the true cable tension when take the higher modes and the principle of half-wave method calculation cable force is simple, model of complex cable can be avoided through analysis of equivalent single cable.