Select the SLS Parameters tab from the New Reinforcement Parameters dialog.
- Define the range of calculations in the Serviceability Limit State (SLS) while designing an RC plate (panel).
- Cracking. Calculations of the cracking width.
- Reinforcement correction (cracking). Automatic correction of cracking width by increasing reinforcement area.
- Deflection. Calculations of the RC plate deflection with cracking considered.
- Reinforcement correction (deflections). Automatic correction of deflections by increasing reinforcement area.
- You can define the allowable values of cracking width and/or of deflection. If these values are exceeded, the results table will report relevant information. Cracking width is defined in two ways (separately for the top and bottom areas).
- Choose the environment class resulting in a cracking width in accordance with code requirements.
- Enter a value of cracking width. A change of the environment class has no effect on the adopted value of the cracking width.
If the Reinforcement correction option is selected, the defined values are also the limit values. Reinforcement area is increased for these values to be reached.
- You can also determine the ratio of variable loads to long-term loads.
Variable loads may be divided into short-term and long-term loads. The long-term to variable coefficient specified in the Ratio of loads is used to split variable loads into a short-term part and a long-term part according to the following formula.
variable load = (1 - c) * variable load + c * variable load = short-term load + long-term load,
where c is a coefficient of the participation of long-term loads in variable loads.
- You can also specify:
- Concrete creeping coefficient (creep coefficient, fi according to Figure 7.1 in BS 8110). The concrete creeping coefficient may be selected automatically in compliance with code requirements after defining the concrete age at the loading moment (Figure 7.1 in BS 8110).
- Concrete age (loading moment) is used in calculations of modulus of elasticity of the concrete (part 7.2 of BS 8110)).
- Environment humidity (relative environment humidity - Figure 7.1 in BS 8110) may also be entered.
Deflection in plates is calculated on the basis of the ratio of elastic stiffness to the stiffness determined on the basis of the phase of RC element work (see: Deflections of plates and shells - calculations).
Deflection of RC plates is identified with displacement. While working in 3D with plates and shells or while using elastic supports in the 2D plate module, pay attention to the displacement of supports that may change the value of actual deflections.
The lower part of the dialog may include additional RC code specific parameters such as the following.
- American code: how long a long-term load is acting on the structure, x coefficient.
- UK code: concrete age, concrete creeping coefficient, relative environment humidity.
- Polish code: concrete age, concrete creeping coefficient.