Constant stress arch in network tied-arch bridges

Abstrakti

Recent advancements and practical applications of tied-arch bridges have rendered the network tied-arch bridge an alternative for short and medium-span arch bridges. The present paper proposes a methodology for the calculation of the moment free constant stress arch shape for network tied-arch bridges. The forces exerted by the network hanger and tie are calculated to carry the deck as a continuous girder on fixed supports. In the bridge, the hangers will be adjusted to the calculated forces. It is assumed that the arch structure in calculation is incompressible. The calculation provides material quantities for the arch, tie tendons and hanger cables. Comparisons are drawn with the moment free constant cross-section tied-arch bridge. The calculations are based on a proposed network system that has been selected with the objective of resolving the issue of loose hangers. The optimality of the span-to-rise relation and the cost-effectiveness of the example bridges is demonstrated by including the arch height in the cost function of the steel arch. A comparison of the results with FEM calculations is undertaken to identify the correspondence to real bridge structures. To the authors’ knowledge, a closed-form iterative procedure for determining a moment-free constant-stress network arch based on hanger-force equilibrium has not previously been reported.