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Eurocode 2 SLS design of I-shaped, T-shaped, and box-shaped reinforced concrete cross-section for stress limitation

Description:
SLS design of I-shaped, T-shaped, and box-shaped reinforced concrete cross-section for stress limitation (calculation of required reinforcement for given bending moment / axial force, maximum moment resistance for given axial force, or complete M-N interaction diagram for given reinforcement layout)
According to:
EN 1992-1-1:2004+AC2:2010 Section 7.2
Applicable for:
Uniaxial bending. Box-shaped cross-section can be treated as an equivalent I-shaped cross-section accounting for the total width of webs. Reinforcement layers of the flanges can be concentrated at the centerline of the corresponding flange as an approximation.
Supported National Annexes:
No Nationally Defined Parameters (NDPs) in the calculation
All Calculations
Input
MPa
e.g. 30 MPa for concrete class C30/37. For a list of concrete classes see Table of Concrete Design Properties
According to EN 1992-1-1 §7.2(2) to avoid longitudinal cracks the compressive stress in the concrete should be limited to 0.6fck for the characteristic SLS combination for adverse environment (exposure classes XD, XF, XS) and in the absence of other measures. According to EN 1992-1-1 §7.2(3) the effects of non-linear creep should be considered when the compressive stress in the concrete exceeds 0.45fck for the quasi-permanent SLS combination
The parabolic stress-strain law may be used for SLS (no partial safety factors) according to EN1992-1-1 §3.1.7(1) Figure 3.3. The linear stress-strain law (without tension) is a good approximation and it can also take into account an effective modulus of elasticity e.g. due to the effects of creep or aggregate type.
A value of 1.0 corresponds to the value of the secant modulus of elasticity Ecm as defined in EN1992-1-1 Table 3.1. To take into account the long-term effects of creep a value of 1 / [1 + φ(∞, t0)] can be provided, as specified in EN 1992-1-1 §7.4.3(5). To take into account more refined values of the modulus of elasticity based on the aggregate type an appropriate value can be provided, e.g. as specified in EN 1992-1-1 §3.1.3(2) and the National Annex.

MPa
MPa
According to EN 1992-1-1 §7.2(5) tensile stress in the reinforcement should be limited to 0.8fyk for the characteristic SLS combination. A lower value may be needed to satisfy the crack control requirements for the relevant combination (typically SLS quasi-permanent) e.g. according to EN 1992-1-1 §7.3.3.

m
m
m
m
m
m

Initial reinforcement: When the required reinforcement is requested the initial reinforcement will be modified accordingly.

Enter 0 to disable the bottom reinforcement layer. Non-integer values are handled by suitable modification of bar cross-sectional area.
mm
m

Enter 0 to disable the top reinforcement layer. Non-integer values are handled by suitable modification of bar cross-sectional area.
mm
m
Distance from bar centroid of top reinforcement layer to concrete edge

Enter 0 to disable the side reinforcement layer. Non-integer values are handled by suitable modification of bar cross-sectional area.
mm

kNm
The design value of the bending moment at the appropriate SLS combination for which the required reinforcement will be determined
kN
The design value of the axial force at the appropriate SLS combination for which the maximum bending moment resistance of the cross-section will be calculated
The specified layers will be modified proportionally by multiplication by the same factor. The rest of the layers will remain unchanged.
I-beam or T-beam concrete cross-section
I-beam or T-beam concrete cross-section