The Experimental Research On Digital Tension Technology Of Prestressed Concrete

Digital tension technology of prestressed concrete is to use digitizer in tension construction. It is the particular application of modern information technology in civil engineering construction. The research on digital tension technology has important backgrounds of engineering and broad prospects of application. Intelligent tension instrument of prestressed concrete is a kind of digitizer with the function of intelligent display and control. The instrument matching ordinary tension device can be used repetitively. It is a patent developed by our subject group. The instrument has been applied to spot construction for the first time on the construction site of commanding and dispatching center of Channeling Water from Huanghe River in Wanjiazhai of Shanxi. Digital and sensing technology is employed to accomplish the dual open loop control over the tension of prestressing tendon. Because the traditional technology of prestressing construction is improved, construction accuracy and efficiency are greatly raised. It is digital tension technology that helps to avert accidents in prestressing construction successively.The site experimental research has. been conducted accurately on prestress losses due to friction and due to the deformation of ahchorage devices and on interrelation between the different prestressing tendon during the course of tension. Digital and sensing technology was first utilized to carry out the investigation on the influence of fluctuations of temperature on prestress. It is concluded that prestressing construction ofreinforced concrete frame structure of high building without taking the effect of temperature into account simply couldn't satisfy the requirement of quality criteria in force. Theoretical formulae are given to precisely calculate the instantaneous prestress losses of prestressing tendon with many waves curve. The formulae are very practical. It is more general than that proposed in current codes. A computer program is also presented on calculating the instantaneous prestress losses and the tension value of prestressing tendon, which can be used conveniently in design or in construction. A technology procedure on digital construction of unbonded prestressed concrete is introduced which will direct construction and help to popularize the digital tension technology in engineering practice.The experimental results and the conclusions in this thesis have great theoretical significance to prestressing construction and high-applied value. Furthermore, they are very valuable for developing prestressing tension robot in future.