Behaviour of Self-Supporting Communication Tower Subjected to Wind Load

Abstract

The main objective of the Project is the “Behaviour Of Self-Supporting Communication Tower Subjected To Wind Load” The thesis deals with the study of the behaviours of self supporting tower under static and dynamic loading cases. The study is extended for the behaviour of tower in both face and corner wind0cases. As wind force plays a major role as far as loading is considered in tall structures. For the details study of this project a case study is done0considering a 100m high self supporting tower. In addition to the wind loading the loads of the communication antennas that will come on the tower are also considered. It describes the wind load calculations, analysis procedure and design of tower members. The tower is analyzed for both corner wind and face wind directions. Analysis if performed using SAP 80/90. The basic activity starts with modelling of the tower. Modelling of tower is an assembly structure with different configuration parts stands one above the other, each we call it as BAY. For this come typical bay types are formatted which could be used as data for generation of tower configuration. These typical configurations shall help in generation0of easy model with different options in achieving the required parameters of optimum design results of0minimum tonnage of the total structure with allowable deflections at maximum wind in both static and dynamic cases. Wind load and antenna load calculations0are carried out by using ‘C’ program. Tower configuration, wind load calculations on tower, dimensions and properties of the tower (input to ‘C’) are explained by taking typical Bay-1. For analysis of tower, the required formatted input for Structural0Analysis Program (SAP) is obtained by ‘C’) program output. Member forces are obtained by genol 1.f3f file (SAP output file). All tower members are designed as axially0loaded compression members as per standard specifications. Design of members are carried out for maximum0member forces obtained by both corner and face wind analysis. If capacity of member is less than member force higher sections0are selected and analysis & design is carried out until member capacity is more than member force. Output (analysis & design data for all members is obtained using member0forces file and “Design” C program file. This output is shown in Tables. Foundation forces and joint displacements are obtained by SAP output file (genol.sol) and the maximum deflection is checked as per specifications. In the tower structures, the leg members are governed0when the wind acts in corner direction. Similarly the horizontal and diagonal members are governed when wind acts in face direction. The results tabulated shows0the forces that are changing in static and dynamic loading.