Analysis and Design of Cable-Stayed Bridge and Cost Comparison with Typical Bridge

Abstract

In the recent years cable stayed bridges have received more attention than any other bridge mainly due to their ability to cover large spans. Cable stayed bridges have proved to be emerging option to negotiate large valleys of water ways. Due to superiority and less number of substructures, propagation and development of cable stayed bridges has increases substantially. Options of cable stayed bridge for road over bridge in city limit is also assessed and a few of th projects are implemented and completed. With the development of material technology, spans which were considered impractical are now easily negotiated. Cable stayed bridge technology has grown along with the growth of material technology and construction technology. Examples like Milau viaduct, Tatatra bridge of Japan are few examples of limit that can be easily reached by cable stayed bridges. In India few of the cable stayed bridges are constructed and a couple of them are underway. Second Hoogly Bridge is the finest example of application of cable stayed bridge in India. Cable Stayed bridges for road over bridge in Bangalore and Chennai have come up and a Cable stayed road over bridge is proposed at Nagpur. Cable Stayed bridge technology is relatively new in India and designers are still reluctant about cable stayed alternate. The main cause is the cost factor which in general perception is very high. The cost of cables is actually very high as compared to other materials used in construction. Moreover it requires anchorages complication that results in increased cost. However high cost of cables is nullified by less number of substructures and reduced thickness of deck, lowering the cost of bridge. The contractors for such specialized jobs are very limited in India. But increase in number of cable stayed bridges can give wide exposure in this field which will ultimately lower the construction cost. An attempt has been made to investigate the cost of a cable stayed bridge. A span of 288 mts (overall), 160 mts central span and a side span of 64 mts on either sides for the construction of cable stayed bridge. Analysis of the bridge is carried on SAP-2000 followed by design and costing of the bridge components. The cost of cable stayed bridge is compared with conventional type of bridge assumed to be constructed on the same span. A conclusion on the cost of cable stayed bridge is drawn at the end of study. iv The first Chapter consists of introduction to the cable stayed bridge, various components of the bridge, methods of construction, protection, types of stays etc. Second Chapter introduces to the methods of analysis linear and nonlinear analysis, dynamic analysis, iterative methods, seismic analysis and use of computers for the analysis. Third Chapter is the literature review for the cable stayed bridge with various literatures on analysis and design of the bridge, various parameters of the bridge design and various effects on the bridge. Fourth Chapter discusses the use of SAP- 2000 software for the analysis of bridge structure. A beginning to end of the procedure of analysis of the structure using SAP-2000. Discussed in detail are various aspects of modeling and analysis for the analysis to be carried out. Fifth Chapter is the analysis result and design of various components like cable stays, pylon, deck, pile group and pile cap. Sixth Chapter consists of quantity sheets of various components designed in previous chapter and the abstract sheet of the quantities of various components. Seventh Chapter discusses the parametric study carried for various bridges with various configurations. Bridges with varying height of pylon 24 m, 32 m, 40 m and cables 24 nos., 30 nos. and 36 cables are taken and results for the for axial force and bending moment in pylon cable and deck are discussed. Further more is discussed the comparison of the cost of cables, pylon and deck. Eighth Chapter is the comparison of cost of cable stayed bridge for study with the conventional I-girder Prestressed bridge. Nineth Chapter discusses the conclusion and future scope of work for the topic.