Evaluation of In-plane Buckling and Ultimate Strength for Braced Arch Ribs

The parametric analysis of vertically braced steel pipe arch ribs was performed to evaluate their in-plane buckling strengths and ultimate load-carrying capacities. The elastic and plastic behavior of braced arch ribs, unlike those of the usual single arch ribs, are affected by such factors as the flexural rigidity of the brace member, brace and pipe ribs spacing, loading situation, and arch curvature. To analyze these effects, several parameters were included, such as the rise-to-span ratio, the second moment of the inertia ratio of the rib to the brace member, the space ratio of the brace, the space ratio of the upper and lower ribs, the initial crookedness, the slenderness ratios of the braced arch ribs, and the loading conditions were considered with live-load-to-dead-load ratios. Based on the results of the parametric analyses, a proper profile of the braced arch rib was proposed. A large-scale structural experiment was also performed to evaluate the ultimate strength of the braced arch rib. The test results were determined to reasonably coincide with the analytical ones.