The safety of steel bridges around capital region under severe conditions

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In the present study we synthesize investigations for steel bridges around capital region under severe condition on different aspects such as ultimate load carrying capacity subjected to fatigue and buckling, estimation of wind load, earthquake load, and severe traffic live load, and anti-earthquake design. With a purpose to ensure the safety of steel bridges around capital region, the following studies are carried out.(1) On fatigue; Establishment of data base for fatigue cracking in steel bridges. The evaluation of fatigue crack growth from blowholes. Simulation of fatigue crack growth in highway bridges. Feasibility study on detection of fatigue crack in fillet welded joint. Retrofitting fatigue-cracked joints by tig arc remelting.(2) On ultimate load carrying capacity; Estimation of ultimate strength of stiffened steel plates. Simplified analysis and optimality on the steel column behavior. Analysis of cable-stayed bridges subjected to nonuniform support.(3) On severe traffic live load; Measurement of weigth of moving vehicles. Simulation for evaluating extremes of traffic live load on highway bridges. Stress reduction factor for fatigue assessment of highway bridges. Effect of multiple presence of vehicles on fatigue damage of bridges.(4) On dynamic problems; Dynamic uplifting of flexible structure on compliant ground. Experimental study on tuned liquid damper using circular containers.(5) On design method; Influence analysis of the factors of safety on the design of bridges. Effects of gross errors for determining the factors of safety. A Method to determine fractile values from statistical data.