Reinforced Concrete Constructions

For users of a software program for solid construction, the implementation and integration of the relevant design standards and the comprehensibility of the results is of critical importance.

For this, InfoCAD provides comprehensive functions such as the single design or detailed listings for each element. The latest eurocode standards with the national annexes supported.

See also: EN 1992-1-1 checks, modulus of compressibility method, punching shear check, rain storage reservoir

Actions and Combinations

Based on actions, the program uses the relevant safety and combination coefficients to automatically construct the design situation for the ultimate limit state and the serviceability limit state. The resulting extremal design values are then provided for the checks. Alternatively, you can also carry out the checks for all combinations rather than just the extreme values of the load.

Ultimate Limit State

Ensuring Ductile Component Behavior
To prevent a component from failing without notice during initial crack formation, a minimum reinforcement is put into place to cover the crack moment with
As = Mr,ep / (fyk · zs ).

Bending Design
Im Rahmen der Biegebemessung wird der Nachweis der Tragsicherheit für Biegung mit oder ohne Längskraft und Längskraft allein für räumlich beanspruchte Stab- und Flächenquerschnitte durchgeführt. Die für jede Schnittkraftkombination erforderliche Bewehrung wird unter Beachtung der von der jeweiligen Norm vorgegebenen Grenzdehnungslinie ermittelt. Das endgültige Resultat ergibt sich aus dem Extremwert aller berechneten Bewehrungen. Bei einer Druck-gliedbemessung wird die Bewehrung symmetrisch angeordnet und zusätzlich die entsprechende Mindestbewehrung vorgesehen.

Lateral Force
Lateral force design involves determining the diagonal tensile reinforcement and includes a concrete strut check. The necessity of a lateral force reinforcement is analyzed first. For components with the required lateral force reinforcement, the design value of the concrete longitudinal stress is taken into account and the strut angle is limited depending on the amount of stress. Optionally, you can also raise the allowable bending tensile reinforcement to prevent shear stirrups.

Torsion
Torsion design involves determining the diagonal tensile reinforcement and the longitudinal reinforcement and includes a concrete strut check under maximum torsional stress, combined with a concrete strut check under lateral force.

Shear Joint Check
The shear force transmission in the concrete joint of a cross-section is verified for beams and design objects with predominant shear force in z-direction. The required reinforcement can be displayed in tabular and graphical form.

Punching Shear
The load-bearing safety check with respect to punching shear is performed interactively at the support of a shell structure. During this check, the determinant punching force can be taken from the static calculation (e.g., from the permanent and temporary or accidental design situation).
The program makes recommendations for the required longitudinal and/or stirrup reinforcement. The location of the supports in relation to the edge and any openings is taken into account. All necessary perimeters as well as the minimum reinforcement are checked and then applied. A detailed log documents the entire calculation.

Fatigue Check
The fatigue check for concrete and steel is carried out for load-bearing components that are not subject to primarily static actions. The stress range originating in condition II is checked for each steel layer and increased if necessary. The check for concrete under pressure is likewise carried out at the cracked section.

Serviceability Limit State

Limiting the Concrete Compressive Stresses
Concrete compressive stresses are limited to prevent longitudinal cracks from occurring under the rare action combination. If the serviceability, load-bearing capacity or durability of the structure is predominantly influenced by creepage, then this also need to be limited under the quasi-continuous action combination.

Limiting the Reinforcing Steel Stresses
The steel stresses are checked by determining the strain state at the cracked concrete section. The tensile stresses are limited under the rare action combination for this check. The reinforcement corresponds to the maximum value from the robustness, crack and bending reinforcement, including a possible increase as a result of the fatigue check.

Crack Width Limitation
Crack formation is essentially unavoidable in areas where concrete is subject to tensile stress. The crack width should be limited such that proper use of the structure as well as its appearance and durability are not compromised as a result of cracks. The crack width limitation check includes checking the minimum reinforcement and calculating the crack width.

Minimum Reinforcement for the Crack Width Limitation
This reinforcement is dimensioned to compensate forced actions and residual stresses and designed for the internal force combination that leads to initial crack formation in accordance with the corresponding requirement class.

Crack Width Check
The crack width is determined for the final longitudinal reinforcement (maximum from the robustness, crack and bending reinforcement including a possible increase resulting from the fatigue check). The steel stress of the reinforcement is derived using the check combination defined by the requirement class in condition II. The reinforcement is increased until the prescribed crack width is maintained.

Limiting Deformations
The deformations in the serviceability state are determined with regard to the existing reinforcement and the bending rigidities that result from it. A residual tensile stress can be used to record how the concrete contributes to the tension between the cracks (tension stiffening).

Determining Maximum Reinforcement

The design of the extremal internal forces from the action combinations does not necessarily lead to the maximum reinforcing steel reinforcement. Frequently there are combinations with lower internal forces that result in higher reinforcement levels. Therefore, all internal force combinations can be checked in the InfoCAD program system as an option.

Load-Bearing Safety Check and Deformations in Condition II

The nonlinear system analysis for all standards and structure types can be used to perform a load-bearing safety check for the entire system (e.g., for movable frames with regard to effective rigidities or to determine deformations in condition II).