The arc cutout of orthotropic steel bridge deck suffered from cracks in short term service.The main cause of fatigue cracking is the stress concentration caused by unreasonable arc cutout design.The improved arc cutout by thermal cutting can effectively reduce the stress of the diaphragm under vehicle load,but it will produce a high level of residual stress and affect the fatigue life.Therefore,a fatigue maintenance scheme of combining thermal and cold maintenance is proposed.The cutout is optimized and improved by thermal cutting,and the steel plate is pasted at the connection between the longitudinal rib and the transverse diaphragm for reinforcement.Software ABAQUS is used to establish the steel box girder segment model,the vehicle stress before and after maintenance is calculated.the thermal cutting residual stress test is carried out.and the distribution of residual stress of arc cutout by thermal cutting is analyzed through numerical simulation.The vehicle stress and residual stress by thermal cutting are coupled based on the steel constitutive model.Combined with the measured traffic data,the fatigue life of arc cutout considering the influence of residual stress by thermal cutting is calculated by using the linear fatigue cumulative damage theory,and the effects of different maintenance schemes are compared and analyzed.The results show that the improvement of arc cutout by thermal cutting can significantly improve the problem of stress concentration and the peak value of compressive stress under vehicle load is reduced by 50％.However,the improved arc cutout will produce a high level of residual stress,which will significantly affect its fatigue performance,the fatigue life is only 67.75 years,which is lower than the design life of the bridge,pasting steel plate on the improved cutout for cold maintenance can further reduce the stress peak of the arc cutout,the peak stress of 10mm steel plate bonded on both sides is reduced by 79％,and its fatigue life is significantly increased.When the reinforced steel plate with the same thickness is used,the fatigue maintenance effect of single-sided pasting is better than that of double-sided pasting.The scheme of thermal maintenance and cold maintenance proposed in this paper can reduce the influence of thermal cutting residual stress and obtain better fatigue maintenance effect,which provides a new technical choice for the fatigue maintenance of arc cutout of steel bridge deck.
维普
万方数据