Members

In the Members tab of the "Ultimate Configurations" dialog box, you can make basic settings for the ULS design of members and member sets.

The "Design Parameters" are divided into several categories.

Consider Internal Forces for Concrete Design

In this category, you can control the member internal forces N, M_y, M_z, V_y, V_z, and M_T for the design, and define which internal forces are taken into account in the design.
This allows you, for example, to neglect the torsional moment in the design of a rib. To do this, define a new ultimate configuration, deactivate the torsional moment M_T, and use this configuration for the rib.

Reduction of Internal Forces in z-Direction

In this category, you can make the settings for the "moment redistribution", "moment reduction", or "moments at the face of a monolithic support", and the "reduction of shear forces".

For the individual options, the corresponding sections of the standard are specified. The check boxes control whether to modify the design moment M_y or reduce the shear force V_z in the design.

Chapter Design Supports and Deflection describes how to define supports for the concrete design, and how to define settings of a monolithic support or the ratio δ for the moment redistribution for an inner support.

The following image shows the design ratios for the shear force design UL0200.02 with the reduction of the shear force V_z (upper diagram) and without the reduction of the shear force V_z (lower diagram).

Further information about the shear force reduction in member design can be found in the following articles in our Knowledge Base:

• Shear Force Reduction V_z (for RFEM 5, the concept also applies to RFEM 6)
• Defining Design Supports

Required Longitudinal Reinforcement

Reinforcement Layout

Using the reinforcement layout, you can influence the determination of the required longitudinal reinforcement. There are various options available in the list (see the image Reinforcement Layout).

The "Reinforcement Layout"' affects the distribution of the required longitudinal reinforcement, which is always output after the design – regardless of whether the individual design checks are fulfilled or not. If a member with the defined longitudinal reinforcement is not sufficiently dimensioned after the design, you can compare this distribution of the required reinforcement to the distribution of the provided reinforcement and use it to determine the "uncovered reinforcement". This is then available as a result.

Distribute Reinforcement Evenly over Complete Slab Width

This option allows you to determine whether to use the entire slab width of the rib member (the entire chord width) or the width of the rectangular cross-section only when determining the required longitudinal reinforcement.

Include Tensile Force Due to Shear in Required Longitudinal Reinforcement

This check box controls whether to include the tensile force component due to the shear force (the tensile force cover) when determining the required longitudinal reinforcement.

Detailing and Particular Rules

When designing members, you can optionally check the design specifications regarding the "minimum longitudinal reinforcement", the "minimum reinforcement ratio", or the "minimum shear reinforcement". If one of these design checks is not fulfilled with the given reinforcement, you can either exclude the design here or adjust the reinforcement.

Required Shear Reinforcement – Shear Capacity

There are three options to select from in order to determine the required shear reinforcement.

In the default setting, the statically required longitudinal reinforcement is used to determine the shear force resistance V_Rd,c. Since this option causes the longitudinal reinforcement ratio ρ_l to differ from x-location to x-location of the member, the shear force resistance along the member is not constant, but depends on the required longitudinal reinforcement.

As an alternative, you can apply the provided longitudinal reinforcement to determine the shear force resistance V_Rd,c. If a constant longitudinal reinforcement has been defined along the member, the applied longitudinal reinforcement ratio ρ_l is constant as well.

The third option allows you to increase the required longitudinal reinforcement to avoid shear reinforcement. This means that the required longitudinal reinforcement is not only influenced by the bending design, but also by the shear force design: The program increases the required longitudinal reinforcement until V_Ed = V_Rd,c.

Shear Joint

In this category, you have the option to design shear joints of casting segments and the shear forces between the beam web and the flange. By selecting the "Design of shear joint" check box, you activate the design of joints, for example, in concrete additions for precast members. Thus, other options for entering the parameters according to EN 1992‑1‑1, 6.2.5, appear.

Neutral Axis Depth Limitation

According to EN 1992‑1‑1, it is necessary to perform the neutral axis depth limitation design, depending on the analysis method (elasticity or plasticity analysis). Whether this design is carried out by default, depends on the National Annex. For example, this option is activated for the design according to DIN EN 1992‑1‑1.

Calculation Setting

A gross concrete section is generally used for the section design checks. However, if you want to take into account a net section (a gross section minus a reinforcement section) in the section design, for example, due to a higher reinforcement ratio, select the "Net concrete area" check box.