DEVELOPING PIPELINE TRUSS BRIDGE USING TUBULAR SECTIONS

Abstract

The day-to-day industrial growth of our country increases the demand of petroleum products. Since the sites of production of these are usually far away from the sites of consumption, the transportation poses a big problem. The existing roads and railways have proved to be not only inadequate but also unsafe, uneconomical and prone to delays. Pipelines offer a viable and much cheaper alternative while at the same time ensuring an almost uninterrupted supply. In the offshore,, artic and hilly regions, they are the only means of effiCient and economic petroleum transportation. Truss bridges offer an efficient solution in the span range of 10 to 60m for the pipelines which are quite often taken over obstacles, by erecting bridges. Since a large number of such bridges would be required in a vast country like ours, it may be worth to maintain the economy in addition to the safety and stiffness of the bridge. Also the development of a computer software for analysis and design of pipeline bridges decreases the tedious manual computation effort and ensures accuracy of the calculations, besides saving much time. • This thesis has been devoted mainly to check the economy by adopting tubular sections in truss construction in place of usual rolled steel sections, without sacrificing the safety of the pipeline bridge. So, more importance has been given to the utilization of the tubular sections including its connection iii facilities. In the present work a computer software has been checked, modified and used for the analysis and design of pipeline bridges using tubular sections. The software has also been extended to incorporate the design of connections for the tubular sections. A more accurate 3D analysis has been used which is not feasible if the computations are done manualy, thus affecting additional saving. A case of 30m span bridge has been manually solved using the conventional 2-D approach and the results obtained have been utilized to adjust the software, other bridge spans of 40m, 50m and 60m are also analysed, maintaining the same bridge cross-section. Forces in typical members, deflection due to various loads and total weight of steel work are tabulated. Also, a comparative study has been carried out between the two designs, using tubular and rolled steel sections, where it is observed that 1 about -3-rd weight of material is saved in the case of tubular section while the deflections still remain within the prescribed limits, ensuring adequate stiffness in the structure for the range of spans upto 60m. Iv