“…The project of South-to-North Water Transfer crossing yellow river adopts rectangular aqueduct with thin wall, the flow of water is 120m3/s, basic dimensions of section are as follows: a=1m,b=0.2m,h=5.4m,d=0.5m,L=12m, e=0.5m, considering the symmetry of aqueduct ,calculation should be within the span of l/2, there are 48 elements in calculation, the top flange has 3 elements, side wall has 25 elements, and there are 18 elements above neutral axis, the other 7 elements under neutral axis, the bottom has 20 elements, there are 49 nodes, and there is Where q,l is the upper load applied on aqueduct and the span of aqueduct respectively , international system of units is adopt in the process of calculating , the unit of max c is MPa , the maximum compressive stress-15.54MPa in top flange plate and siding shingle locates on the top flange plate of mid-span ,while the maximum stress of top flange plate and siding shingle is 32MPa calculated by Semi-analytical Finite Plate Strip Method ( considering the critical stress that is got in the condition of elastic instability is greater than strength limit of C50 concrete [10] and the former can not be larger than the latter , so instead the former with the latter). If the structure occurs failure it may be plastic instability or overload of pressure [11] [12].…”