Concrete is a widely used construction material with high compressive yet low tensile strengths. Its poor performance in tension must therefore be addressed by incorporating steel reinforcement in the area where tensile strength has to be enhanced; compression reinforcement is also sometimes needed to provide additional strength and stiffness. Strand7 provides a design tool to model and analyse reinforced concrete structures of custom geometry and properties using plate elements.
The reinforcements results can be viewed as a contour and as a listing. The results can also be peeked and graphed when necessary. Most importantly, the units of the reinforcement results can be set to suit the reading requirements.
The available reinforcement results consist of Wood-Armer moments, calculated steel area, calculated concrete strain, and the concrete block ratio. The results in all layers can be extracted.
- Wood-Armer Moments - These are moments to be resisted by each layer of reinforcement calculated according to the published equations, which allow designers to make allowance for plate bending and twisting moments when designing the reinforcement within a reinforced concrete panel.
- Steel Area (As) - This gives the required reinforcement for a balanced section supporting the calculated moment and membrane forces (if specified). The results can be calculated at each layer and can be presented in one of five different ways:
- /Length: The total amount of reinforcement steel required in terms of total cross sectional area of the steel bars per unit width of slab.
- Spacing: Based on the nominal bar diameters defined in the reinforcement layout, spacing between the steel bars for the chosen layer is calculated.
- Bar diameter: Based on the nominal bar spacings defined in the reinforcement layout, bar diameter for the chosen layer is calculated.
- /A_slab: The ratio of the reinforcement cross-sectional area to the cross-sectional area of the slab.
- /A_base: The ratio of the amount of reinforcement to the base amount specified in the reinforcement layout. This value indicates if the base amount of reinforcement specified by the Codes is sufficient.
- Steel Area (As - As_b) - This gives the extra amount of reinforcement required in addition to the base amount of steel specified in the reinforcement layout. The options are the same as Steel (As), but the values have the base amount subtracted, that is, (As - As_base).
- Steel Stress (User) - The stress of each layer of steel reinforcement may be extracted. The steel property defined in the reinforcement layout is used to determine the stress due to the loadings.
- Concrete Strain - Only available for the elasto-plastic iteration. This gives the strain in the concrete at the chosen reinforcement layer.
- Concrete Block Ratio - Only available for the Simplified bending method. This gives the size of the rectangular stress block as a ratio of plate thickness.
An example of the Steel Area (As) /Length contour is shown below. The area of steel is calculated such that the reinforcement starts to yield.