This article explains the construction of the double reinforced section. The basic steps to be followed are explained in a simple way for better understanding. Several methods with different names are discussed in the literature. However, all methods lead to the same result, even if they look different in presentation.
- The value x/d = 0.5 is taken into account in all calculations: Information.
- The effective depth (d) is calculated based on the coverage and assumed diameters of the connection and rod.
- Calculated depth for compression bars (d')
- Calculate K = M / (bd 2 F ck ); where “M” is the applied bending moment, “b” is the width of the beam, “d” is the effective depth and “fck” is the characteristic cylindrical strength of the concrete.
- Check K > K' = 0.167. If this is met, the section must be designed as double reinforcement, otherwise it must be designed as a single reinforced section, as in another item .
- Calculate the d'/d ratio and check whether it is less than 0.171. If this is met, it can be assumed that the compression reinforcement has yielded. This expression was derived considering x/d = 0.45. In addition, there are several other methods to check the yielding of compression reinforcement. It is recommended to carry out the check before proceeding with reinforcement calculations.
- Calculated area of compressive reinforcement for step 8 equation
- Like'=(KK')f ck bd 2 / (0.87f Yes (dd'))
- Determine the lever arm Z = d (0.5 + √ (0.25 – K / 1.134)) from this equation, considering K = K' = 0.167, or using the equation Z = 0.82d, which is for the equilibrium state below. x/d = 0.45 is derived.
- Check Z < 0.95d. If true, use the same, otherwise use Z = 0.95d.
- Calculate the tensile reinforcement requirement from the equation in step 12
- How = (K'f ck bd 2 / 0.87f Sim Z) + How'
- Check for minimum reinforcements. is given > 0.26 (f CTM /F Sim )bd, but not less than 0.0013bd, where f CTM is the average value of the central tensile strength of the concrete, which can be found in Table 3.1: Strength properties and concrete deformation according to Eurocode 2.
- Check maximum earnings; (100 A is supplied /A C ) < 4
