Study On Application And Analysis Of Reliability Of Pole And Tower Structure In Transmission Line Under Wind Load

Wind load effect is the main controlling internal force in designing the pole and tower structures in transmission line and it directly affects the reliability of the structures. Extra-voltage (750KV,±800KV,1000KV) transmission lines are planned to be built in china. Current codes'Technical Regulation of design for tower and pole structures of overhead transmission line'(DL/T 5154-2002) and'Technical code for designing 110~500kV overhead transmission line'(DL/T 5092-1999) for designing pole and towel structures in transmission line are not suitable yet, how to determinate the value of wind load and other design parameters is the urgent task which should be solved immediately. This paper based on reliability theory studies on the method for determining the value of wind load and the importance factor of structures in extra voltage transmission line. In addition, how to design the structure with minimum material consumption but assure the reliability of structure is another task in this paper. Research work in details is given as follow:①The principle and methods of structure reliability were introduced. The methods of calculating the reliability of elements were introduced. The advantage and disadvantage of each method had been presented, and the JC method had been chosen for computing reliability in the paper, corresponding program had been developed. When refers to the reliability of structure system, the methods for system reliability calculating were introduced.②According to the provision of'Technical Regulation of design for tower and pole structures of overhead transmission line', when consider the dead load and wind load combinations on the normal condition, the design parameters which affect the reliability index of tower and pole structure were studied. The connotative reliability indexes in current tower and pole structure design criterion were analyzed at the end of this section.③According to the influent regularity of design parameters on reliability of pole and tower structure, a method for determining the value of wind load and the importance factor of structure in designing important projects such as the extra-voltage transmission line had been presented, then used this method, gave suggestions to the yunnan to guangdong extra-voltage transmission line, the suggestions has been adopted as outcome of corresponding research.④In the part of reliability-based tower optimizing, the method which on the constraint condition of the tower structure system reliability and set the minimum weight as the object had been introduced. According to the theory of this method, a program has been developed, and then a space truss model was given to illuminate the effect of optimizing.