CONCRETE | Features

The fatigue design according to EN 1992-1-1 must be performed for the structural components subjected to large stress ranges and/or many load changes. In this case, the design checks for the concrete and the reinforcement are performed separately. There are two alternative design methods available.

Using an example of a steel fiber-reinforced concrete slab, this article describes how the use of different integration methods and of a different number of integration points affects the calculation result.

When it comes to wind loads on building type structures as per ASCE 7, numerous resources can be found to supplement design standards and aid engineers with this lateral load application. However, engineers may find it more difficult to find similar resources for wind loading on non-building type structures. This article will examine the steps to calculate and apply wind loads as per ASCE 7-22 on a circular reinforced concrete tank with a dome roof.

• Import of results from RSTAB
• Integrated material and cross-section library
• The module extension EC2 for RSTAB enables design of reinforced concrete according to EN 1992-1-1 (Eurocode 2) and the following National Annexes:
  • DIN EN 1992-1-1/NA/A1:2015-12 (Germany)
  • ÖNORM B 1992-1-1:2018-01 (Austria)
  • Belgium NBN EN 1992-1-1 ANB:2010 for design at normal temperature, and NBN EN 1992-1-2 ANB:2010 for fire resistance design (Belgium)
  • BDS EN 1992-1-1:2005/NA:2011 (Bulgaria)
  • EN 1992-1-1 DK NA:2013 (Denmark)
  • NF EN 1992-1-1/NA:2016-03 (France)
  • SFS EN 1992-1-1/NA:2007-10 (Finland)
  • UNI EN 1992-1-1/NA:2007-07 (Italy)
  • LVS EN 1992-1-1:2005/NA:2014 (Latvia)
  • LST EN 1992-1-1:2005/NA:2011 (Lithuania)
  • MS EN 1992-1-1:2010 (Malaysia)
  • NEN-EN 1992-1-1+C2:2011/NB:2016 (Netherlands)
  • NS EN 1992-1 -1:2004-NA:2008 (Norway)
  • PN EN 1992-1-1/NA:2010 (Poland)
  • NP EN 1992-1-1/NA:2010-02 (Portugal)
  • SR EN 1992-1-1:2004/NA:2008 (Romania)
  • SS EN 1992-1-1/NA:2008 (Sweden)
  • SS EN 1992-1-1/NA:2008-06 (Singapore)
  • STN EN 1992-1-1/NA:2008-06 (Slovakia)
  • SIST EN 1992-1-1:2005/A101:2006 (Slovenia)
  • UNE EN 1992-1-1/NA:2013 (Spain)
  • CSN EN 1992-1-1/NA:2016-05 (Czech Republic)
  • BS EN 1992-1-1:2004/NA:2005 (United Kingdom)
  • CPM 1992-1-1:2009 (Belarus)
  • CYS EN 1992-1-1:2004/NA:2009 (Cyprus)
• In addition to the National Annexes (NA) listed above, you can also define a specific NA, applying user‑defined limit values and parameters.
• Optional presetting of partial safety factors, reduction factors, neutral axis depth limitation, material properties, and concrete cover
• Determination of longitudinal, shear, and torsional reinforcement
• Design of tapered members
• Cross‑section optimization
• Representation of minimum and compression reinforcement
• Determination of editable reinforcement proposal
• Crack width analysis with optional increase of the required reinforcement in order to keep the defined limit values of the crack width analysis
• Nonlinear calculation with consideration of cracked cross‑sections (for EN 1992‑1‑1:2004 and DIN 1045‑1:2008)
• Considering tension stiffening
• Considering creep and shrinkage
• Deformations in cracked sections (state II)
• Graphical representation of all result diagrams
• Fire resistance design according to the simplified method (zone method) according to EN 1992‑1‑2 for rectangular and circular cross‑sections. Thus, fire resistance design of brackets is possible as well.

After the calculation, the module shows clearly arranged tables listing the required reinforcement and the results of the serviceability limit state design. All intermediate values are included in a comprehensible manner. In addition to the tables, current stresses and strains in a cross‑section are represented graphically.

The reinforcement proposals of the longitudinal and the shear reinforcement, including sketches, are documented in accordance with current practice. It is possible to edit the reinforcement proposal and to adjust, for example, the number of members and the anchorage. The modifications will be updated automatically.

A concrete cross‑section, including reinforcement, can be visualized in a 3D rendering. This way, the program provides an optimal documentation option to create reinforcement drawings, including steel schedule.

Crack width analyzes are performed using the selected reinforcement of internal forces in the serviceability limit state. The result output covers steel stresses, the minimum reinforcement, limit diameters, and the maximum bar spacing, as well as crack spacing and the maximum crack widths.

As a result of the nonlinear calculation, there are the ultimate limit states of the cross‑section with defined reinforcement (determined linear elastically) as well as effective deflections of the member considering stiffness in cracked state.

After opening the program, you can define the standard and method according to which the design is performed. The ultimate and serviceability limit states can be designed according to the linear and nonlinear calculation methods. Load cases, load combinations or result combinations are then assigned to different calculation types. In other input windows, you can define materials and cross‑sections. In addition, it is possible to assign parameters for creep and shrinkage. Creep and shrinkage coefficients are directly adjusted, depending on the age of the concrete.

Support geometry is determined by means of design‑relevant data such as support widths and types (direct, monolithic, end, or intermediate support) and redistribution of moments as well as shear force and moment reduction. CONCRETE recognizes the support types from the RSTAB model automatically.

A segmented window includes the specific reinforcement data such as diameters, the concrete cover and curtailment type of reinforcements, number of layers, cutting ability of links, and the anchorage type. In the case of the fire resistance design, it is necessary to define the fire resistance class, the fire‑related material properties, and the cross-section side exposed to fire. Members and sets of members can be summarized in special 'reinforcement groups', each with different design parameters.

You can adjust the limit value of the maximum crack width in the case of crack width analysis. The geometry of tapers is to be determined additionally for the reinforcement.