RF-/CONCRETE Columns | Design

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.

For the bending failure design, the governing locations of the column are analyzed for axial force and moments. In addition, locations with extreme values of shear forces are considered for the shear resistance design. During the calculation, it is determined whether a standard design is sufficient or whether the column with the moments has to be designed according to the second-order theory. These moments are then determined based on the previously entered specifications. The calculation has four parts:

• Load-independent calculation steps
• Iterative determination of governing loading taking into account a varying required reinforcement
• Determination of the designed reinforcement for governing internal forces
• Safety determination of all acting internal forces, including the designed reinforcement

In this way, RF-/CONCRETE Columns provides a complete solution of an optimized reinforcement concept and the resulting load actions.

After the calculation, the results are displayed in clearly arranged tables. Each intermediate value is listed, making the design checks transparent.

The module creates a reinforcement concept for the longitudinal and the shear reinforcement considering all constructional specifications. The reinforcement is represented by a 3D drawing, including dimensions. You can adjust the reinforcement concept to your individual requirements. A 3D graphic shows the exact distribution of strain and stress across the cross-section.

If any of the fire resistance designs is not fulfilled, RF-/CONCRETE Columns increases the required reinforcement until either all designs are performed successfully or no reinforcement layout can be found. You can visualize the columns and their reinforcement in the 3D rendering as well as in the work window of RFEM/RSTAB. In addition to the input and result data including design details displayed in tables, you can add all graphics into the printout report. This way, comprehensible and clearly arranged documentation is guaranteed.

The members to be designed are directly imported from RFEM/RSTAB. Load cases, load combinations, and result combinations are assigned, which result in the linear-elastically determined internal forces on the selected members. When considering creeping, the creep-producing load must also be defined. The RFEM/RSTAB materials are preset but can be adjusted in RF-/CONCRETE Columns. The material properties listed in the respective standard are included in the material library.

You can easily define constructional properties of columns as well as other details for determining the required longitudinal and shear reinforcement. The effective length factor ß is to be defined manually, determined automatically by the module, or imported from the RF-STABILITY/RSBUCK add-on module.

The fire resistance design according to EN 1992-1-2 requires various specifications; for example, determination of cross-section sides where burn-off occurs.