A 16 mm thick plate measuring 650 mm ^_x 420 mm is used as a base plate for an ISHB 300 column subjected to a factored axial compressive load of 2000 kN. As per IS 456-2000, the minimum grade of concrete that should be used below the base plate for safely carrying the load is

Consider a reinforcing bar embedded in concrete. In a marine environment, this bar undergoes uniform corrosion, which leads to the deposition of corrosion products on its surface and an increase in the apparent volume of the bar. This subjects the surrounding concrete to expansive pressure. As a result, corrosion induced cracks appear at the surface of concrete. Which of the following statements is TRUE?

Consider two RCC beams P and Q, each having the section 400 mm ^_x 750 mm (effective depth, d = 750 mm) made with concrete having a ^{$\tau_{c max}$}= 2.1 N/mm². For the reinforcement provided and the grade of concrete used, it may be assumed that the ^$\tau_c$= 0.75 N/mm². The design shear in beam P is 400 kN and in beam Q is 750 kN. Considering the provisions of IS 456 — 2000, which of the following statements is TRUE?

Consider a bar of diameter ‘D’ embedded in a large concrete block as shown in the adjoining figure, with a pull out force P being applied. Let ^$\sigma_b$ and ^{$\sigma_{st}$} be the bond strength (between the bar and concrete) and the tensile strength of the bar respectively. If the block is held in position and it is assumed that the material of the block does not fail, which of the following options represents the maximum value of P?

As per India standard code of practice for pre stressed concrete (IS:1343 –1980) the minimum grades of concrete to be used for post-tensioned and pre-tensioned structural elements are respectively

Direction: A doubly reinforced rectangular concrete beam has a width of 300 mm and an effective depth of 500 mm. The beam is reinforced with 2200 mm² of steel in tension and 628 mm² of steel in compression. The effective cover for compression steel is 50 mm. Assume that both tension and compression steel yield. The grades of concrete and steel used are M20 and Fe250 respectively. The stress lock parameters (rounded off to first two decimal places) for concrete shall be as per IS 456:200.

The moment of resistance of the section is

Direction: A doubly reinforced rectangular concrete beam has a width of 300 mm and an effective depth of 500 mm. The beam is reinforced with 2200 mm² of steel in tension and 628 mm² of steel in compression. The effective cover for compression steel is 50 mm. Assume that both tension and compression steel yield. The grades of concrete and steel used are M20 and Fe250 respectively. The stress lock parameters (rounded off to first two decimal places) for concrete shall be as per IS 456:200.

The depth of neutral axis is

In the design of a reinforced concrete bean the requirement for bond is not getting satisfied. The economical option to satisfy the requirement for bond is by

Unfactored maximum bending moments at a section of a reinforced concrete beam resulting from a frame analysis are 50, 80, 120 and 180 kNm under dead, live, wind and earthquake loads respectively. The design moment (kNm) as per IS: 456- 2000 for the limit state of collapse (flexure) is

A reinforced concrete column contains longitudinal steel equal to 1 percent of net cross sectional area of the column. Assume modular ratio as 10. The loads carried (using the elastic theory) by the longitudinal steel and the net area of concrete are P_s and P_c respectively. The ratio P_s/P_c expressed as percent is

A reinforced concrete structure has to be constructed along a sea coast. The minimum grade of concrete to be used as per IS: 456-2000 is

For limit state of collapse, the partial safety factors recommended by IS 456 : 2000 for estimating the design strength of concrete and reinforcing steel are respectively

The modulus of rupture of concrete in terms of its characteristic cube compressive strength (f_ck) in MPa according to IS 456 : 2000 is

Column I gives a list of test methods for evaluating properties of concrete and Column II gives the list of properties.

The correct match of the test with the property is

A rectangular concrete beam of width 120 mm and depth 200 mm is prestressed by pretensioning to a force of 150 kN at an eccentricity of 20 mm. The cross-sectional area of the prestressing steel is 187.5 mm². Take modulus of elasticity of steel and concrete as 2.1 _^x10⁵ MPa and 3.0 _^x10⁴ MPa respectively. The percentage loss of stress in the prestressing steel due to elastic deformation of concrete is