The object of this problem is to design a truss or beam bridge. b) Your designed bridge should be a) A 50 tons load should be in the dashed box. applied on the middle of the bridge. 3m 4m c) Fixed boundary c) Fixed boundary 12m 1. A 2D or 3D FEM model is required. The width of bridge is Im. 2. The Element type is truss. 3. Material define: a) Young's modulus of steel: 2.1e11N/m2 b) Poisson's ratio: 0.26 c) Density of steel: 7800kg/m3 4. The weight of the bridge is considered as a load. 5. The maximum deflection of bridge should be less than 5cm. 6. The weight of bridge should be small enough. The lighter, the better. 7. Project report is required (.docx or pdf). The title, description of the problem,, the introduction of design model, the calculation results, the conclusion, are included in the report. An APDL commands file should be attached on this ort.