The composite post in Figure 1.49 has the same properties and dimensions as in Problem 1.13, except that there is a gap = 0.1

The composite post in Figure 1.49 has the same properties and dimensions as in Problem 1.13, except that there is a gap Δ = 0.1 mm between the top of the cover plate on the post and the upper support. An upward load P is applied to the rigid cover plate, which is securely attached to the concrete and the steel reinforcing rods. If the deformation due to the load P is just enough to close the gap Δ, determine the resulting stresses in the concrete and the steel rods, and the magnitude of the load P. Note that Figure 1.49 shows the position of the cover plate before the gap Δ has been closed.

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.

A gap distance 0.1 mm. = 1.2 m FIGURE 1.49 11/1 Rigid cover plate Postcross section P Steel rods (4) As 0.00125 m each Concrete 0.3 m x 0.3 m 0.3 m 0.3 m