| Cable dome structure has reasonable stress and is suitable for roof design of longspan buildings.However,there are relatively few studies on dynamic performance and component breakage in cable dome model tests in China at present;the safety rating method of component is single and has not yet formed a system;only a few cases of health monitoring for actual cable dome structure are limited by the number of projects.In this paper,the health monitoring of cable dome of Tianjin University of Technology is carried out,and the cable(rod)breakage test and finite element simulation are carried out on the scale model.The changing law of external environment and structural state during the normal service period of long-span cable dome,the breaking effect of cable dome structural components and the safety rating of different types of components are mainly studied.The method can provide some reference and basis for the design and monitoring of cable dome structure.In the aspect of health monitoring of cable dome structure in Tianjin University of Technology,five aspects of strut stress,cable force,ambient temperature,roof wind environment and structural vibration are given and analyzed by finite element method.It is concluded that the temperature field is uniform and consistent in the whole year when the temperature is 8-36?.The stress of the brace and the cable force are greatly affected by the temperature and have an inverse correlation.The stress range of the brace is 5.5-8.5MPa and the loss range of the cable force is 3.3-18.3% for each 10? rise.In terms of cable(rod)breakage test and finite element analysis,three types of cable breakage were selected in the 1:15 scale model and wire-by-wire breakage test was carried out for one of them.The cable dome cable-breaking effect is vividly described by collecting and processing the whole structure image,the vertical displacement and acceleration of the node,and the dynamic and static strain change of the cable.It is concluded that the damage to the structure is not necessarily the greatest when the member with the greatest stress in the cable dome structure is damaged,and the safety rating of the cable dome member should be made.Through finite element analysis,the structural state and related time history of cable dome before and after cable breakage are effectively simulated,which further verifies the above conclusions.In order to quantitatively describe the dynamic effect of cable breakage,the concept of dynamic amplification factor(DAF)is introduced and the concept of time-history amplification factor(TAF)is proposed.The conclusion is that the breaking effect of the outer ring is the largest,the chord is the second,and the diagonal cable is the smallest.From the four factors of prestressing level,vertical load,boundary condition and temperature,the degree of influence on dynamic effect of cable breakage is analyzed.From large to small,the order is vertical load and prestressing level,temperature and boundary condition.Among them,DAF and TAF increase first and then decrease with the increase of vertical load;they are positively correlated with the level of prestressing force;they are inversely correlated with the change of temperature;the influence of boundary conditions is small and can be ignored.In the aspect of safety rating,76 types of cables and poles are analyzed separately,and the state and response of the broken structure of the whole member are obtained.The idea of component importance rating is put forward: from the perspective of vertical displacement,component internal force,dynamic effect and re-destruction probability,the early warning idea is fused,and five importance levels are divided.From high to low,they are annulus,notochord and strut,diagonal and straight cables.The location of a component has a decisive impact on the importance level.It makes the construction and maintenance of this kind of structure more pertinent,and provides valuable reference for its health monitoring and safety anti-terrorism. |
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