Abstract:The safety reserve of the shear resistance at the pivot point of the prestressed hollow slab girders is lower than it in mid-span bending, and its overloading may leads to excessive diagonal crack widths in the webs at the slab ends. In the scheme, a combination of demolition and new construction can be considered, using (1) partial use of the centre span bridge and (2) widening and reconstruction.The bridge demolition is a critical project, using (1) a comparison of the loading efficiency of the car load and the crane load to check the mid-span bending moment (2) setting up transverse distribution beams so that the plate girders can withstand the larger shear forces generated by the crane pivot points (3) controlling the unbalanced moment of the side columns when the cover beam is removed. To carry out the design of the load carrying capacity of the bridge structure under the most unfavourable working conditions during demolition and lifting.
