Applied Research On Prestressed Cable Tension Test Of The Single Cable Curtain Wall Base On Frequency Method

With the development of socity and economy,the curtain wall is widely used,especially the fine view of the cable(rod)structure point of the glass curtain wall.Prestressed cable is an essential component of this kind of curtain wall,it's force state is important for forming the prestressed structural system of glass curtain wall and affects the safety of this system.Naturally,the monitoring of cable prestressing during construction becomes a necessary task in curtain wall engineeringwhich can guarantee the safety of curtain wall system in service stage.Frequency method is one of the commonly used methods of cable prestressing test,which is efficient and convenient.This method is based on the frequency of the cable,and the pre-tension of the cable is obtained by the relationship between the natural frequency and the cable force.Most of the existing studies focus on the cable-stayed cable and sling of cable-stayed bridge,and there is only a few of studies focus on the cable of curtain wall which cause the lack of corresponding experience and theory.This paper is based on the cable force test of Chongqing Jiangbei International Airport new T3 A terminal single cable glass curtain wall,and the main content is as follows:(1)According to the condition of construction for Chongqing Jiangbei International Airport new T3 A terminal single cable glass curtain wall,227 cables which is available for testing are selected and its force is obtained.(2)Based on the results of cable force test,vibration curve with time history of each table is obtained,and by combing with the spectrum analysis,the corresponding natural frequency is avaliable.Besides,the formula of string theory and hinge theory are used for the force of cable,respectively,and the results indicate that both of the above formulas are not accurate.(3)Analyse the error of above formulas,it is found that flexural rigidity of cable,mass per unit length and cable length are not the main source of error,and the error of natural frequency is the source.(4)By analyse to the results of natural frequency,the position of the vibrator,the length of the test period and he sampling points are shown to have no effect on the natural frequency.Furthermore,results of error analysis and finite element analysis prove that the error of natural frequency is cause by the calculation model which belongs to systematic error.(5)By comparing the results of pressure gauge test with the one of frequency method,coefficients of correction for formula of string theory and hinge theory are proposed respectively,and the force of cable is alse modified.