Utilizing the Steel Design Add-on, steel design is possible according to the AISC 360-22 standard. The following article will compare the result output when calculating lateral torsional buckling according to Chapter F vs. an Eigenvalue Analysis.
The evaluation of story drift in a building is crucial to ensure acceptable structural performance by limiting the drift amount. Excessive drift has the potential to induce system instability and may cause damage to nonstructural components such as partitions. This article outlines the procedure for establishing interstory drift according to ASCE 7-22 and the Building Model add-on in RFEM 6.
The ASCE 7-22 Standard [1], Sect. 12.9.1.6 specifies when P-delta effects should be considered when running a modal response spectrum analysis for seismic design. In the NBC 2020 [2], Sent. 4.1.8.3.8.c gives only a short requirement that sway effects due to the interaction of gravity loads with the deformed structure should be considered. Therefore, there may be situations where second-order effects, also known as P-delta, must be considered when carrying out a seismic analysis.
The three types of moment frames (Ordinary, Intermediate, Special) are available in the Steel Design add-on of RFEM 6. The seismic design result according to AISC 341-22 is categorized into two sections: member requirements and connection requirements.
Using the Timber Design add-on, timber column design is possible according to the 2018 NDS standard ASD method. Accurately calculating timber member compressive capacity and adjustment factors is important for safety considerations and design. The following article will verify the maximum critical buckling strength calculated by the Timber Design add-on using step-by-step analytical equations as per the NDS 2018 standard including the compressive adjustment factors, adjusted compressive design value, and final design ratio.
The Steel Design add-on in RFEM 6 now offers the ability to perform seismic design according to AISC 341-16 and AISC 341-22. Five types of seismic force-resisting systems (SFRS) are currently available.
The three types of moment frames (Ordinary, Intermediate, Special) are available in the Steel Design add-on of RFEM 6. The seismic design result according to AISC 341-16 is categorized into two sections: member requirements and connection requirements.
Moment frame design according to AISC 341-16 is now possible in the Steel Design add-on of RFEM 6. The seismic design result is categorized into two sections: member requirements and connection requirements. This article covers the required strength of the connection. An example comparison of the results between RFEM and the AISC Seismic Design Manual is presented.
The design of an Ordinary Concentrically Braced Frame (OCBF) and a Special Concentrically Braced Frame (SCBF) can be carried out in the Steel Design add-on of RFEM 6. The seismic design result according to AISC 341-16 and 341-22 is categorized into two sections: Member Requirements and Connection Requirements.
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.
Both the determination of natural vibrations and the response spectrum analysis are always performed on a linear system. If nonlinearities exist in the system, they are linearized and thus not taken into account. They are caused by, for example, tension members, nonlinear supports, or nonlinear hinges. This article shows how you can handle them in a dynamic analysis.
To be able to evaluate the influence of local stability phenomena of slender structural components, RFEM 6 and RSTAB 9 provide you with the option of performing a linear critical load analysis on the cross-section level. The following article explains the basics of the calculation and the result interpretation.
When a concrete slab is set upon the top flange, its effect is like a lateral support (composite construction), preventing problems of torsional buckling stability. If there is a negative distribution of the bending moment, the bottom flange is subjected to compression and the top flange is under tension. If the lateral support provided by the stiffness of the web is insufficient, the angle between the bottom flange and the web intersection line is variable, so there is a possibility of distortional buckling of the bottom flange.
Custom sections are often required in cold-formed steel design. In RFEM 6, the custom section can be created using one of the “Thin-Walled” sections available in the library. For other sections that do not meet any of the 14 available cold-formed shapes, the sections can be created and imported from the standalone program, RSECTION. For general information on AISI steel design in RFEM 6, refer to the Knowledge Base article provided at the end of the page.
The CSA S16:19 Stability Effects in Elastic Analysis method in Annex O.2 is an alternative option to the Simplified Stability Analysis Method in Clause 8.4.3. This article will describe the requirements of Annex O.2 and application in RFEM 6.
The design of cold-formed steel members according to the AISI S100-16 is now available in RFEM 6. Design can be accessed by selecting “AISC 360” as the standard in the Steel Design add-on. “AISI S100” is then automatically selected for the cold-formed design (Image 01).
Windbreak structures are special types of fabric structures which protect the environment from harmful chemical particles, abate wind erosion, and help to maintain valuable sources. RFEM and RWIND are used for wind-structure analysis as one-way fluid-structure interaction (FSI).
This article demonstrates how to structural design windbreak structures using RFEM and RWIND.
This article discusses the options available for determining the nominal flexural strength, Mnlb for the limit state of local buckling when designing according to the 2020 Aluminum Design Manual.
The optimal scenario in which punching shear design according to ACI 318-19 or CSA A23.3:19 should be utilized is when a slab is experiencing a high concentration of loading or reaction forces occurring at one single node. In RFEM 6, the node in which punching shear is an issue is referred to as a punching shear node. The causes of these high concentration of forces can be introduced by a column, concentrated force, or nodal support. Connecting walls can also cause these concentrated loads at wall ends, corners, and ends of line loads and supports.
You can model and analyze masonry structures in RFEM 6 with the Masonry Design add-on that employs the finite element method for the design. Complex masonry structures can be modeled, and static and dynamic analysis can be performed, given that a nonlinear material model is implemented in the program to display the load-bearing behavior of masonry and the different failure mechanisms. You can enter and model masonry structures directly in RFEM 6 and combine the masonry material model with all common RFEM add-ons. In other words, you can design entire building models in connection with masonry.
The effects due to snow load are described in the American standard ASCE/SEI 7-16 and in Eurocode 1, Parts 1 through 3. These standards are implemented in the new RFEM 6 program and the Snow Load Wizard, which serves to facilitate the application of snow loads. In addition to this, the most recent generation of the program allows the construction site to be specified on a digital map, thus allowing the snow load zone to be imported automatically. These data are, in turn, used by the Load Wizard to simulate the effects due to the snow load.
In accordance with Sect. 6.6.3.1.1 and Clause 10.14.1.2 of ACI 318-19 and CSA A23.3-19, respectively, RFEM effectively takes into consideration concrete member and surface stiffness reduction for various element types. Available selection types include cracked and uncracked walls, flat plates and slabs, beams, and columns. The multiplier factors available within the program are taken directly from Table 6.6.3.1.1(a) and Table 10.14.1.2.
The stability checks for the equivalent member design according to EN 1993-1-1, AISC 360, CSA S16, and other international standards require consideration of the design length (that is, the effective length of the members). In RFEM 6, it is possible to determine the effective length manually by assigning nodal supports and effective length factors or, on the other hand, by importing it from the stability analysis. Both options will be demonstrated in this article by determining the effective length of the framed column in Image 1.
In this article, the adequacy of a 2x4 dimension lumber subject to combined biaxial bending and axial compression is verified using the RF-/TIMBER AWC add-on module. The beam-column properties and loading are based on example E1.8 of AWC Structural Wood Design Examples 2015/2018.
Structure stability is not a new phenomenon when referring to steel design. The Canadian steel design standard CSA S16 and the most recent 2019 release are no exception. Detailed stability requirements can be addressed with either the Simplified Stability Analysis Method in Clause 8.4.3 or, new to the 2019 standard, the Stability Effects in Elastic Analysis method provided in Annex O.
For the design of concrete surfaces, the rib component of the internal forces can be neglected for the ULS calculation and for the analytical method of the SLS calculation, because this component is already considered in the member design. To do this, select the check box in the "Details" dialog box. If no rib was defined, this function is not available.
RF-CONCRETE Members for RFEM or CONCRETE for RSTAB propose an automatically created reinforcement to the user if the "Design the provided reinforcement" option is selected in Window 1.6 "Reinforcement".