The bridge has a continuous girder and a truss. All truss members have the same cross-sectional area of 2 in.2 and can deform axially. Assume that the girder is axially rigid with the moment of inertia given in the diagram. E = 29,000 ksi for all members. (a) Determine the number of DOF's and the stiffness matrix. (b) Condense out the DOF's at D using static condensation and calculate the stiffness matrix. (c) Determine the deflection at B. (c) Draw the shear and moment diagrams for the girder showing all critical values. (d) Find the axial forces in the truss members. (Do not use the matrix transformation method. But you can use a calculator or any math tools to solve the matrix equations.) 
 

Hinge A D 20 ft. B I = 240 in.4 20 kips A = 2 in. 10 ft. 10 ft. 10 ft.