The section of a solid one-way slab is shown in the figure. The concrete is a normal density concrete with a unit weight of 2400 kg/m³ strength of fy = 276 MPa. The reinforcing steel used has a IONS B2 B1 Вз 4m 1 8m 1. Calculate the minimum thickness of slab B1 in millimeters. INO 2. Calculate the minimum required thickness of slab B2 in millimeters. 3. Calculate the minimum required thickness of slab B3 in millimeters. SNOIKRONK

Concrete is required for a column that will be Severe exposed to freezing and thawing. The cross section of the column is 300 × 300 mm. The smallest spacing between reinforcing steel is 30 mm. The Required Average Compressive Strength of concrete at 28 days is 35 MPa with a slump of 80 to 100 mm. The properties of materials are as follows: ❖ Cement used is type I Portland cement with a specific gravity of 3.15. ◆ The available coarse aggregate has a maximum size of 23 mm, a dry-rodded unit weight of 1800 kg/m3, a bulk specific gravity (SSD) of 2.7, absorption capacity of 0.55%, and moisture content (SSD) of 0.25%. The fine aggregate has a bulk specific gravity (SSD) of 2.75, absorption capacity of 1.4%, a moisture content (SSD) of 2.5%, and a fineness modulus of 2.70. The aggregates conform to the ASTM C33-84 requirements for grading.

Concrete is required for a column that will be Severe Exposure to freezing and thawing. The cross section of the column is 300 × 300 mm. The smallest spacing between reinforcing steel is 40 mm. The specified compressive strength of concrete at 28 days is 40 MPa with a slump of 25 to 50 mm. The properties of materials are as follows: (a) Cement used is type I Portland cement with a specific gravity of 3.10. (b) The available coarse aggregate has a maximum size of 23 mm, a dry-rodded unit weight of 1800 kg/m3, a bulk specific gravity (SSD) of 2.68, absorption capacity of 0.65%, and moisture content (SSD) of 0.27%. (c) The fine aggregate has a bulk specific gravity (SSD) of 2.75, absorption capacity of 1.5%, a moisture content (SSD) of 2.5%, and a fineness modulus of 2.7,The aggregates conform to the ASTM C33-84 requirements for grading.

The flexural strength (fr) of concrete measured from the bending test is always higher than the direct tensile strength (ft). In reality, the stress in the cracked part of the concrete is lower than ft. Also, failure may occur on the compressive side. Assuming NO tension softening (i.e., the stress in the cracked part stays at ft) and infinite compressive strength (i.e., compressive failure will never occur), draw the stress distribution over the depth of the beam at ultimate failure when the curvature of the section is approaching infinity. With this stress distribution, show that the upper bound of fr/ft is equal to 3.   (Hint: On rotating the section, because the compressive stress can increase well beyond ft, the neutral axis will continue to shift upwards.)