The "Results by Story" table of a building model shows the center of gravity for load cases and load combinations. In addition to the self-weight, the vertical loads of the respective load cases and load combinations are also taken into account.
You can also use the "Center of Gravity and Information About Selected Objects" dialog box to display the center of gravity, taking into account the selected loading.
When modeling stories, you can use the "Semi-Rigid Diaphragm" option for slabs.
In principle, this modeling option selects the same approach as for the "Rigid Diaphragm" modeling of stories. In contrast to the rigid diaphragm, no nodal coupling is carried out from the center of gravity to each FE node. This way, it is possible to take into account the flexibility of the slab.
In the Concrete Design add-on for RFEM 6, you can perform the fire design of reinforced concrete slabs and walls according to the simplified table method (EN 1992‑1‑2, Section 5.4.2 and Tables 5.8 and 5.9).
In the Concrete Design add-on, you have the option to define an existing vertically oriented punching shear reinforcement. This is then taken into account in the punching shear design.
You can neglect openings with a certain area in the building model calculation. This function can be activated in the global settings of the building stories. A warning message appears saying that the openings have been neglected.
In the Construction Stages Analysis (CSA) add-on, you can use built-up cross-sections by means of what are known as phase sections. Parts of a cross-section of the type "Parametric - Massive II" can be activated or deactivated gradually throughout the construction stages.
The seismic design result is categorized into two sections: member requirements and connection requirements.
The "Seismic Requirements" include the Required Flexural Strength and the Required Shear Strength of the beam-to-column connection for moment frames. They are listed in the ‘Moment Frame Connection by Member’ tab. For braced frames, the Required Connection Tensile Strength and the Required Connection Compressive Strength of the brace are listed in the ‘Brace Connection by Member’ tab.
The program provides the performed design checks in tables. The design check details clearly display the formulas and references to the standard.
Global 3D calculation of the global model, where the slabs are modeled as a rigid plane (diaphragm) or as a bending plate
Local 2D calculation of the individual floors
After the calculation, the results of the columns and walls from the 3D calculation and the results of the slabs from the 2D calculation are combined in a single model. This means that there is no need to switch between the 3D model and the individual 2D models of the slabs. The user only works with one model, saves valuable time, and avoids possible errors in the manual data exchange between the 3D model and the individual 2D ceiling models.
The vertical surfaces in the model can be divided into shear walls and opening lintels. The program automatically generates internal result members from these wall objects, so they can be designed as members according to any standard in the Concrete Design add-on.
Shear walls and deep beams of a building model are available as independent objects in the design add-ons. This allows for faster filtering of the objects in results, as well as better documentation in the printout report.
The building story generator in the Building Model add-on provides you with the option to automatically create building stories, depending on the topology of the model.
The modal relevance factor (MRF) can help you to assess to which extent specific elements participate in a specific mode shape. The calculation is based on the relative elastic deformation energy of each individual member.
The MRF can be used to distinguish between local and global mode shapes. If multiple individual members show significant MRFs (for example, > 20%), the instability of the entire structure or a substructure is very likely. On the other hand, if the sum of all MRFs for an eigenmode is around 100%, a local stability phenomenon (for example, buckling of a single bar) can be expected.
Furthermore, the MRF can be used to determine critical loads and equivalent buckling lengths of certain members (for example, for stability design). Mode shapes for which a specific member has small MRF values (for example, < 20%) can be neglected in this context.
The MRF is displayed by mode shape in the result table under Stability Analysis → Results by Members → Effective Lengths and Critical Loads.
In the Concrete Design add-on, you can perform the simplified fire resistance design according to Sections 5.3.2 and 5.6 of EN 1992‑1‑2 for columns and beams.
The following design checks are available for the simplified fire resistance design:
Columns: Minimum cross-sectional dimensions for rectangular and circular sections according to Table 5.2a as well as Equation 5.7 for calculating time of fire exposure
Beams: Minimum dimensions and center distances according to Tables 5.5 and 5.6
You can determine the internal forces for the fire resistance design according to two methods.
1 Here, the internal forces of the accidental design situation are included directly into the design.
2 The internal forces of the design at normal temperature are reduced by the factor Eta,fi (ηfi), then used in the fire resistance design.
Furthermore, it is possible to modify the axis distance according to Eq. 5.5.
With the Concrete Design add-on, you can perform the fatigue design of members and surfaces according to EN 1992‑1‑1, Chapter 6.8.
For the fatigue design, you can optionally select two methods or design levels in the design configurations:
Design Level 1: Simplified design according to 6.8.6 and 6.8.7(2): The simplified design is performed for frequent action combinations according to EN 1992‑1‑1, Chapter 6.8.6 (2), and EN 1990, Eq. (6.15b) with the traffic loads relevant in the serviceability state. A maximum stress range according to 6.8.6 is designed for the reinforcing steel. The concrete compressive stress is determined by means of the upper and lower allowable stress according to 6.8.7(2).
Design Level 2: Design of damage equivalent stress acc. to 6.8.5 and 6.8.7(1) (simplified fatigue design): The design using damage equivalent stress ranges is performed for the fatigue combination according to EN 1992‑1‑1, Chapter 6.8.3, Eq. (6.69) with the specifically defined cyclic action Qfat.