ANALYSIS OF SUPER STRUCTURE OF SURFACE POWER HOUSE.

Abstract

The super structure of a surface power house is an important structure as it houses costly machines and other auxiliary equipments. The power houses are classified depending upon the nature of the super structure, such as indoor, outdoor or semi-outdoor. This study deals with the indoor type of powerhouse where the super structure provides the maximum protection against weather. The super structure of a surface power house consists of a framework of beams and columns that support the panel walls, roof and crane, in addition the control rooms and other auxiliary housings usually form a single framework thus making the structure complicated having both structural and loading asymmetry. The objective of this study is to evaluate the advantages of the space frame analysis of the super structure of the indoor type power house in terms of reduction of forces and moments by comparing it with the conventional two-dimensional approach. . Two frames, one. asymmetrical frame having .a combination of control room, machine 'hall and floors (main frame) and the other a symmetrical frame having only the machine hall (symmetrical frame), have been analyzed by both the two-dimensional and the three-dimensional approaches. The comparison of the results of 3-D and 2-D analyses for both the frames have been carried out . The study reveals that the reduction in the bending moments in gantry columns at the base due to lateral loads is in the range of 20 to 30%. This is a substantial reduction which would result in saving of reinforcement. Therefore wherever possible 3-D analysis of powerhouse frames shall be carried out....