Co-relationship of Seismic (EDR) & (PGA) for Cable Stayed Bridge
Prof A. K. Desai, Dr. J. A. Desai, M.Tech. Dr. H. S. Patil, Department of Applied Mechanics, S V N I T, Surat.
The evolution of the modern cable-stayed bridges took place almost exclusively in postwar Germany in the early fifties. Since then, it has become increasingly popular in many countries because of its remarkable structural efficiency as well as its aesthetically pleasing appearance. As opposed to the classical suspension bridge, the cable-stays are directly connected to the bridge deck resulting in a much stiffer structure. A large number of closely spaced cablestays support the bridge deck throughout its length, reducing the required depth and bending stiffness of the longitudinal girder to a minimum, thereby allowing the construction of relatively longer spans. The structural action is simple in concept: the cables carry the deck loads to the towers and from there to the foundation.
The primary forces in the structure are tension in the cable-stays and axial compression in the towers and deck; the effect of bending and shear is considered to be secondary. The early designs of modern cable-stayed bridges essentiality consisted of a stiff girder supported by a few cables. The stay- forces were rather large and consequently the anchorage design was excessively complex. Further development indicated that these problems could be eliminated by increasing the number of stays. The multi-cable arrangement has following advantages:
The evolution of the modern cable-stayed bridges took place almost exclusively in postwar Germany in the early fifties. Since then, it has become increasingly popular in many countries because of its remarkable structural efficiency as well as its aesthetically pleasing appearance. As opposed to the classical suspension bridge, the cable-stays are directly connected to the bridge deck resulting in a much stiffer structure. A large number of closely spaced cablestays support the bridge deck throughout its length, reducing the required depth and bending stiffness of the longitudinal girder to a minimum, thereby allowing the construction of relatively longer spans. The structural action is simple in concept: the cables carry the deck loads to the towers and from there to the foundation.
The primary forces in the structure are tension in the cable-stays and axial compression in the towers and deck; the effect of bending and shear is considered to be secondary. The early designs of modern cable-stayed bridges essentiality consisted of a stiff girder supported by a few cables. The stay- forces were rather large and consequently the anchorage design was excessively complex. Further development indicated that these problems could be eliminated by increasing the number of stays. The multi-cable arrangement has following advantages:
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NBM&CW March 2008
