Creep effect of concrete slab on mechanical properties of long-span steel-concrete composite bridge
In order to explore the effect of shrinkage and creep of concrete slab on long-span steel-concrete composite bridge,this paper takes the steel-concrete composite bridge of Qinhe River Bridge as the engineering background and uses a finite element model established with Midas Civil software to study the change of stress and deflection of steel-concrete composite bridge in 10 years under the creep effect of concrete slab,and discussed the influence factors such as time history,age of prefabricated slab and relative humidity on the creep effect of steel-concrete composite bridge respectively.The re-sults show that the creep effect of the concrete slab increases the compressive stress on the upper edge and decreases the tensile stress on the lower edge of the steel beam.The creep stress is the highest at the secondary span,the smaller at the middle span and the lowest at the edge span.The creep deflec-tion is the maximumt at the edge span,the smaller at the middle span and the minimum at the second-ary edge span.The creep effect of concrete slab decreases with the increase of time.The maximum effect on deflection is 1 year after the completion of bridge,and the maximum effect on stress is 3 years after the completion of bridge.The increase of age and relative humidity of prefabricated panels can reduce the influence of creep effect on composite beams.The mid-span creep deflection of the bridge at 28 days of age is 1.33 times that of the bridge at 180 days of age,and the mid-span creep de-flection of the bridge at 62%relative humidity is 1.21 times that of the bridge at 79%relative humidi-ty.
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