Figure 1 shows a RC external column (450 mm x 450 mm) of a building. The service dead (permanent) load and service live

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Figure 1 Shows A Rc External Column 450 Mm X 450 Mm Of A Building The Service Dead Permanent Load And Service Live 1 (74.83 KiB) Viewed 6 times

Figure 1 shows a RC external column (450 mm x 450 mm) of a building. The service dead (permanent) load and service live (imposed) load carried by the column are 2500 kN and 1200 kN, respectively. An isolated square footing of size 3000 mm x 3000 mm and depth 800 mm is proposed to transfer the load to the soil below. The column load passes through the centroid of the footing. The allowable bearing capacity of soil is 600 kPa. Drawing is not to scale. For durability considerations, take the characteristic concrete compressive strength f = 25 MPa and a minimum concrete cover of 75 mm. RC weight is 25 kN/m³. (a) Check whether the footing is safe in punching shear. (30 marks) (b) Assuming that the footing is safe in one-way shear and punching shear, determine the area of steel reinforcement needed to carry the design bending moment of the footing (use only N20 bars, area 314 mm²). Assume, Pmin for shrinkage crack control as 75% of 0.0035. (50 marks) (c) Because of the boundary restraint, if the centroid of the footing has to be eccentric with respect to the centre of the column by 400 mm, calculate the additional service moment (in the clockwise direction) the footing will be subjected to. In this scenario check whether the area of the footing would be sufficient from bearing capacity consideration. Draw the subsoil pressure distribution in this case below the footing showing the salient values. (30 marks) D qnet L Figure 1. Isolated footing for Question 1. Question (c) - Imagine your own values assuming (a) & (b) is resolved, and show step-by-step solution. I need to understand how eccentric would work. Please show assumed data separately so that I could understand 1