Structural Optimization Of Simply Supported Light T-Beam With Jointless Bridge Deck

Simply supported structural system with continuous bridge deck is a structural form between the simply supported structural system and the continuous structural system,which effectively balances the relationship between the mechanical properties of structural system and the smooth running of the vehicle.On the other hand,although traditional bridges such as hollow slabs and small box girders are usually used for medium and small highway bridges,their complex structural systems lead to many problems such as difficulties in prefabrication and poor quality control effect.Therefore,the simply supported light T-beam with continuous bridge deck becomes a better solution.Based on theoretical analysis,numerical simulation and engineering test,this paper focuses on the mechanical properties,steel design,local structural measures and key design parameters of the bridge deck continuous structure,and finally obtains the calculation analysis and optimization design method of the bridge.Based on the non-linear interactive model system,the structural system and mechanical properties of the simply supported light Tbeam with continuous bridge deck are studied,and the effects of continuous bridge deck of different lengths on the overall mechanical properties,local stress state and spatial distribution of cracks are comparatively analyzed,and the structural analysis methods and steel design methods are determined.The main research work and conclusions of this paper include:1.Based on the non-linear interactive model system,the mechanical properties of simply supported light T-beams with continuous bridge deck considering the effect of stiffness degradation are studied,and the effect of stiffness degradation on the accuracy of numerical simulation is fully considered.The effects of different bridge deck continuous zone lengths on the overall mechanical properties of the bridge,the local stress state of bridge deck continuous zone and the occurrence and development of concrete cracks are compared and studied.It is found that by optimizing the length of bridge deck continuous zone,the bridge can be calculated and analyzed according to the mechanical model of simply supported beam bridge.At the same time,the cracks in bridge deck continuous zone will reduce the restraint stiffness of bridge deck continuous zone to light T-beam.2.Based on the optimization of the length of bridge deck continuous zone,the steel design scheme of this type of bridge is further studied.It is found that the arrangement of longitudinal rotary protruding steel bar has an important influence on the optimization of mechanical properties of light T-beam,and the diameter of steel bars should not be too large or too small.Through repeated revision of the non-linear interactive model system,the reasonable value of the diameter of the longitudinal rotary protruding steel bar is obtained,which makes the bridge deck continuous zone absorb the negative moment in the span reasonably,effectively control the stress of the steel bar to be lower than the yield stress,and avoid making the width of the concrete crack exceed the limit.3.Based on the refined non-linear finite element model,the construction measures of steel slip in bridge deck continuous zone are studied,and the effect of steel slip on the overall mechanical properties of light T-beam and local mechanical properties of bridge deck continuous zone are compared and studied.It is found that the effect of steel slip has a significant effect on the local mechanical properties of the bridge deck continuous zone.By taking reasonable structural measures,the steel bar can slip,the stress of the longitudinal rotary protruding steel bar can be effectively reduced,and the development of concrete cracks can be effectively controlled.4.Based on the above research work,the influence of the main girder joint length on the local mechanical properties of the bridge deck continuous zone is further studied.It is found that the main mechanical properties tend to be reasonable with the increasement of the main girder joint length,and the span arrangement has no significant effect on the optimization of the main girder joint length,and the effect of steel slip does not change the influence of the length of main girder joints on the local mechanical properties of the bridge deck continuous zones.