SIMPLIFIED CONTINUOUS BEAM DESIGN
Problem
Design grade 45, 5-span continuous reinforced concrete beam subjected to 1.15kN/m superimposed dead load and 2.00kN/m live load. The critical span length is 5m, and the dimension of beam section is 200mm x 600mm. Take cover to reinforcement as 25mm.
Solution
- Arrange the reinforcement in beam section.
- Determine the factor for design bending moment based on Table 3.5, BS8110-1:1997.
- Calculate the design bending moment as per Table 3.5, BS8110-1:1997.
- Determine the effective depth to tension reinforcement.
- Determine whether singly reinforced section is sufficient as per cl.3.4.4.4, BS8110-1:1997.
- Determine the lever arm of tension reinforcement in beam section using the formulation provided in cl.3.4.4.4, BS8110-1:1997.
- Determine the depth to neutral axis in beam section using the formulation provided in cl.3.4.4.4, BS8110-1:1997.
- Determine the effective depth to compression reinforcement if doubly reinforced section is required, in accordance with cl.3.4.4.4, BS8110-1:1997.
- Calculate the ratio of effective depth to compression reinforcement : depth to neutral axis as per cl.3.4.4.4, BS8110-1:1997, and then determine the yield strength of compression reinforcement.
- Determine the area of compression reinforcement required based on cl.3.4.4.4, BS8110-1:1997.
- Determine the area of tension reinforcement required based on cl.3.4.4.4, BS8110-1:1997.
- Check whether the area of compression and tension reinforcements provided are greater than minimum requirement as stated in Table 3.25, BS8110-1:1997, while less than maximum limit as per cl.3.12.6.1, BS8110-1:1997.
- Determine the factor for design shear force by referring to Table 3.5, BS8110-1:1997.
- Calculate the design shear force based on Table 3.5, BS8110-1:1997.
- Calculate design shear stress developed in beam section as per cl.3.4.5.2, BS8110-1:1997.
- Determine concrete shear strength based on the method provided in Table 3.8, BS8110-1:1997.
- Calculate the Asv/Sv required based on Table 3.7, BS8110-1:1997.
- Provide sufficient Asv/Sv by manipulating the shear link diameter and spacing.
- Based on the support condition of end and interior spans of beam, determine the basic span to effective depth ratio by referring to Table 3.9, BS8110-1:1997.
- Calculate the stress developed in reinforcing steel by referring to Table 3.10, BS8110-1:1997.
- Determine the modification factor due to tension reinforcement based on Table 3.10, BS8110-1:1997.
- Calculate length factor based on beam length, referring to cl.3.4.6.4, BS8110-1:1997.
- Calculate the permissible span to effective depth ratio by multiplying the basic ratio with modification factor and length factor.
- Check whether the actual span to effective depth ratio exceeds the permissible ratio.
- Determine the maximum allowable rebar spacing based on the formulation provided in cl.3.12.11.2.4, BS8110-1:1997.
- Determine the minimum rebar spacing by referring to cl.3.12.11.1, BS8110-1:1997.
- Check whether the actual rebar spacing lies between the minimum and maximum limits, as calculated in steps above.
0 Comments