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Consider the rectangular beam shown below. Compute moments and curvatures at: i. First flexural cracking using transformed area concept and the elastic theory approach. ii. When the extreme compression fibre strain is equal to 0.0006. iii. At the onset of yielding (when &s = Ey). iv. At ultimate when the extreme compression fibre reaches 0.0035 strain using the alpha and gamma factors. At ultimate when the extreme compression fibre reaches 0.0035 strain using the rectangular stress block specified by CSA Standard A23.2. Plot the moment-curvature relationship by connecting the above points. Use Hognestad's model for concrete stress-strain relationship (with a linear descending branch beyond the peak) and the appropriate simplification as rectangular stress distribution with a and y factors for solving parts ii, iii, and iv. V. f'. = 50 MPa En = 0.002 fy = 400 MPa (assume bi-linear stress-strain relationship) 400 mm 600 mm 4-25M 100 Section