COMPARATIVE ANALYSIS OF DIFFERENT DESIGN MODELS OF OVERHEAD STORAGE STEEL TANK (30,000 LITRES) CAPACITY

Abstract

This work comprises the documentation of comparative analysis of different design models of overhead
storage steel tank (30,000 litres) capacity and 6m height. The total design load used for analysis was gotten from the weight
of water when filled to capacity; wind load and self weight of the members were also considered in the load analysis. Five
models of the same tank were analysed and designed by varying the span of bracing interval of the bracing members. The
model 1 was braced at 1m intervals, model 2 was braced at 1.5m intervals, model 3 was braced at 2m intervals, and model 4
was braced at 3m intervals and finally model 5 was braced at 6m intervals; all models were double diagonal bracing, pinned
connected and fixed supported. The beam members were analysed and designed using simple analytical approach. Because of
the high degree of statical indeterminacy in the analysis of stanchion and bracing components using manual approach,
Computer aided structural analysis software staad pro v8i 2007 version was employed to analyse and generate member force
details for stanchion and bracing members of each model tested. The maximum compressive force on the stanchion member
of each model was adopted for stanchion design per model. And the maximum force on the bracing member of each model
was adopted for bracing design per model. These were used to design each model and select sections required per model.
After selection of members for various models designed, total weights were computed per model to establish relationship
between span of bracing intervals per model and total weight of steel required per model. This led to a conclusion that longer
span of bracing intervals leads to reduction in total weight of steel required and optimal design of over head storage steel
tanks. This is due to observed reduction of total weight of steel and reduction in repeated connection cost which most often
leads to decrease in total cost.