OTH396: Determine the forces on member ECD. Present your answers by indicating the magnitudes: Civil Engineering Entrance Examination, Assignment, NUS, Singapore

Question 1

Figure Q1 shows a frame structure loaded as shown. Determine the forces on member ECD. Present your answers by indicating the magnitudes and directions of these forces on the free body diagram of member ECD.

Question 2

Identify all special joints and zero force members in the truss structure shown in Figure Q2. Determine the forces in members FJ, CD and DE.

Question 3

An axial member is made of two solid circular rods AB and BC welded together at B and loaded as shown in Figure Q3. Knowing that the average normal stress must not exceed 200 MPa and 140 MPa in rods AB and BC, respectively, determine the smallest allowable values of d1 and d2. For these values of d1 and d2, what is the deformation of the axial member at C given that the Young’s modulus of rods AB and BC are 200 GPa and 100 GPa, respectively.