Structural Stability Statement Essay Example | Topics and Well Written Essays - 1500 words

Structural Stability Statement - Essay Example The weight of the tower is not distributed uniformly along the height of the Tower; there is more material at the base than near the top. The Tower consists of lattice-work columns at each of the four corners, in which diagonals connect four elements, thus making stiff, but lightweight columns. Each primary element is actually composed of many sub elements. The overall structure has a vertical axis between the two columns, but, individually, each column has its own axis that follows the curve of the elements. These axes are idealized as parabolas. Four types of loads act on the Tower: Dead load, Live load, Wind load and Thermal load. Dead load and the Wind load generate more forces as compared to the rest. Owing to its lattice structure, the tower is relatively lightweight and creates a force of only 4.5 kg/cm2 on the foundation. The wind force is one of the chief forces which create horizontal loads over the tower. It can be understood as a type of uniformly distributed load over the entire height of the tower. The overall bending moment from the horizontal wind load will produce tension in one column and compression in the other. Exaggerated action under wind load is shown: The wind pressure on the Tower is stronger near the top than at the bottom, but the wind force is fairly uniform because the Tower is tapered. The wind force will create a higher vertical reaction in the leeward support and a lower vertical reaction in the windward support because the wind alone would create compression in the leeward support and tension in the windward support. In combination with the forces generated by dead load, the forces can be seen as stated in the diagram. Reactions The overall reactions at the base of the Tower are easily found from the wind and gravity loads. Overall vertical and horizontal reactions will develop to balance the respective loads. A moment reaction will also develop to balance the horizontal load applied through its centroid a distance l/2 from the support. The Internal Forces The simplest internal forces are the axial ones, which result from the vertical loads and reactions. They reach a maximum at the base of the Tower. These horizontal forces tend to push the Tower apart but are resisted by the connection all along the Tower and the ground. The columns of the Tower, under the effect of the vertical load, would slide apart if there were no connections between them. These connections, which have been idealized as continuous, experience tension force equal to the horizontal forces they are resisting. The axial force will decrease with height as the vertical load and angle of inclination decrease. The second platform is subjected to the entire load of top and middle part of the tower. The forces at the higher points are lower as compared to the base and hence the higher members have a lesser amount of cross sectional area. The