Reinforced Concrete Constructions

FEM meshing of an office building
FEM meshing of an office building

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.

Checks for reinforced concrete construction:

  • Ultimate limit state
    - Minimum reinforcement against failure without warning
    - Bending with or without normal force or normal force only
    - Lateral force under consideration of the min. level of reinforcement
    - Pure torsion and torsion with lateral force
    - Checks against punching shear
    - Checks against fatigue (concrete and reinforcement)
  • Serviceability limit state
    - Limiting the concrete compressive stresses
    - Limiting the reinforcing steel stresses
    - Minimum reinforcement for the crack width limitation
    - Limiting the crack width via direct calculation
    - Limiting deformations

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.

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

Deformation in condition II
Deformation 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).

References

DIN EN 1990/NA/A1:2012
Nationaler Anhang – National festgelegte Parameter –
(National Annex – Nationally Determined Parameters)
Eurocode: Grundlagen der Tragwerksplanung; Änderung A1.
(Eurocode: Basis of Structural Design; Amendment A1)
Publisher: DIN Deutsches Institut für Normung e. V., Berlin.
Beuth Verlag, Berlin 2012.

DIN EN 1992-1-1/NA:2013/A1:2015
Nationaler Anhang – National festgelegte Parameter –
(National Annex – Nationally Determined Parameters)
Eurocode 2: Bemessung und Konstruktion von Stahlbeton- und Spannbetontragwerken –
Teil 1-1: Allgemeine Bemessungsregeln und Regeln für den Hochbau.
(Design of Concrete Structures - Part 1-1: General Rules and Rules for Buildings).
Publisher: DIN Deutsches Institut für Normung e.V., Berlin.
Beuth Verlag, Berlin 2013.

EN 1990:2002/A1:2005/AC:2010
Eurocode: Basics of Structural Design
Publisher: CEN European Committee for Standardization, Brussels.
Beuth Verlag, Berlin 2010.

EN 1991-1-1:2002
Eurocode 1: Actions on Structures –
Part 1-1: General Actions. Densities, Self-Weight, Imposed Loads for Buildings
Publisher: CEN European Committee for Standardization, Brussels.
Beuth Verlag, Berlin 2002.

EN 1992-1-1:2004/A1:2014
Eurocode 2: Design of Concrete Structures –
Part 1-1: General Rules and Rules for Buildings
Publisher: CEN European Committee for Standardization, Brussels.
Beuth Verlag, Berlin 2010.

EN 1992-2:2005/AC:2008
Eurocode 2: Design of Concrete Structures –
Part 2: Concrete Bridges - Design and Detailing Rules
Publisher: CEN European Committee for Standardization, Brussels.
Beuth Verlag, Berlin 2010.

EN 1998-1:2004
Eurocode 8: Design of Structures for Earthquake Resistance –
Part 1: General Rules, Seismic Actions and Rules for Buildings
Publisher: CEN European Committee for Standardization, Brussels.
Beuth Verlag, Berlin 2006.

Fingerloos, F.; Hegger, J.; Zilch, K.
Eurocode 2 für Deutschland (Eurocode 2 for Germany).
DIN EN 1992-1-1 Bemessung und Konstruktion von Stahlbeton- und Spannbetontragwerken –
Teil 1-1: Allgemeine Bemessungsregeln und Regeln für den Hochbau mit Nationalem Anhang.
(Design of Concrete Structures - Part 1-1: General Rules and Rules for Buildings with National Annex).
Kommentierte Fassung. 1. Auflage 2012. Berichtigungen, Ergänzungen, Austauschseiten September 2013.
(Commented version. 1st edition 2012. Corrections, additions, replacement pages September 2013).
Beuth Verlag, Berlin 2012.

Heft 466 - Grundlagen und Bemessungshilfen für die Rissbreitenbeschränkung im Stahlbeton und Spannbeton.
(Book 466 - Principles and Design Aids for Crack Width Limitation in Reinforced and Prestressed Concrete)
Publisher: Deutscher Ausschuss für Stahlbeton, Berlin.
Beuth Verlag, Berlin 1996.

Heft 600 - Erläuterungen zu DIN EN 1992-1-1 und DIN EN 1992-1-1/NA (Eurocode 2).
(Book 600 - Notes to EN 1992-1-1 and EN 1992-1-1/NA (Eurocode 2) )
Publisher: Deutscher Ausschuss für Stahlbeton, Berlin.
Beuth Verlag, Berlin 1996.

OENORM B 1990-1:2013-01
Eurocode: Grundlagen der Tragwerksplanung –
Nationale Festlegungen zu ÖNORM EN 1990 und nationale Ergänzung.
(Basics of Structural Design - National Specifications for OENORM EN 1990 and National Supplements)
Publisher: ON Österreichisches Normungsinstitut, Vienna.
Österreichisches Normungsinstitut, Vienna 2013.

OENORM B 1992-1-1:2011-12
Eurocode 2: Bemessung und Konstruktion von Stahlbeton und Spannbetontragwerken –
Teil 1-1: Allgemeine Bemessungsregeln und Regeln für den Hochbau –
Nationale Festlegungen zu ÖNORM EN 1991-1-1, nationale Erläuterungen und nationale Ergänzungen.
(Design of Concrete Structures – Part 1-1: General Rules and Rules for Buildings –
National Specifications for OENORM EN 1992-1-1, National Comments and National Supplements)
Publisher: ON Österreichisches Normungsinstitut, Vienna.
Österreichisches Normungsinstitut, Vienna 2011.

SS EN 1990:2011-04
Application of SS EN 1990.
Statue Book of the Swedish Board of Housing, Building and Planning.
Publisher: Swedish Board of Housing, Building and Planning (Boverket).
Karlskrona 2011.

SS EN 1992-1-1:2011-04
Application of SS EN 1992-1-1.
Statue Book of the Swedish Board of Housing, Building and Planning.
Publisher: Swedish Board of Housing, Building and Planning (Boverket).
Karlskrona 2011.

Zilch, K.; Rogge, A.
Bemessung der Stahlbeton- und Spannbetonbauteile nach DIN 1045-1.
(Design of Reinforced and Prestressed Concrete Components According to DIN 1045-1)
Betonkalender 2002, V. 1, pp. 217-359.
Ernst & Sohn Verlag, Berlin 2002.

Zilch, K.; Zehetmaier, G.
Bemessung im konstruktiven Betonbau nach DIN 1045-1 und EN 1992-1-1.
(Design in Concrete Structure Engineering According to DIN 1045-1 and EN 1992-1-1)
Springer-Verlag, Berlin 2006.