For the original concrete composite post design of Problem 1.13, assume that the steel rods are made of 4340 steel, and that the rods are to be replaced by IM9 carbon fiber bundles of the same length in a new design. The new design also calls for the load and deformation in the carbon fiber bundles to be the same as in the steel rods of the original design. Compare the weight of the carbon fiber bundles in the new design with the weight of the steel rods in the original design. As with the original design, assume that the applied load P is just enough to close the gap Δ.

Problem 1.13,

The concrete composite post in Figure 1.47 is 1.2 m long with a 0.3 m × 0.3 m square cross section. The post is reinforced by four vertical steel rods of the same length having a cross-sectional area of A_s = 0.00125 m2 each, and is loaded by a single vertical load P = 500 kN applied on the rigid cover plate as shown below. The modulus of elasticity for concrete is E_c = 17 GPa, whereas the modulus of elasticity of steel is E_s = 200 GPa. Determine the stresses in the steel rods and concrete.

Transcribed Image Text:

Rigid cover plate FIGURE 1.47 P = 500 kN 1.2 m Steel rods (4) A = 0.00125 m each Concrete 0.3 m x 0.3 m Postcross section 0.3 m. 0.3 m