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.
In this article, a lap joint of a ZL purlin on a monopitch roof is modeled and designed using the Steel Joints add-on, and compared with the load-bearing capacity table of the manufacturer.
Compliance with building codes, such as Eurocode, is essential to ensure the safety, structural integrity, and sustainability of buildings and structures. Computational Fluid Dynamics (CFD) plays a vital role in this process by simulating fluid behavior, optimizing designs, and helping architects and engineers meet Eurocode requirements related to wind load analysis, natural ventilation, fire safety, and energy efficiency. By integrating CFD into the design process, professionals can create safer, more efficient, and compliant buildings that meet the highest standards of construction and design in Europe.
In computational fluid dynamics (CFD), complex surfaces that are not completely solid can be modeled using porous or permeability media. In the actual world, examples of such things include windbreak fabric structures, wire meshes, perforated facades and claddings, louvers, tube banks (stacks of horizontal cylinders), and so on.
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.
RWIND 2 is a program for generating wind loads based on CFD (Computational Fluid Dynamics). The wind flow numerical simulation is generated around any building, including irregular or unique geometry types, to determine the wind loads on surfaces and members. RWIND 2 can be integrated with RFEM/RSTAB for the structural analysis and design or as a stand-alone application.
RWIND 2 is a program for generating wind loads based on CFD (Computational Fluid Dynamics). The wind flow numerical simulation is generated around any building, including irregular or unique geometry types, to determine the wind loads on surfaces and members. RWIND 2 can be integrated with RFEM/RSTAB for the structural analysis and design or as a stand-alone application.
In RFEM 6 it is possible to save selected objects (as well as whole structures) as blocks and reuse them in other models. Three types of blocks can be distinguished: non-parameterized, parameterized, and dynamic blocks (via JavaScript). This article will focus on the first block type (non-parameterized).
The new RFEM software generation provides the option to perform stability design of tapered timber members in line with the equivalent member method. According to this method, the design can be performed if the guidelines of DIN 1052, Section E8.4.2 for variable cross-sections are met. In various technical literature, this method is also adopted for Eurocode 5. This article demonstrates how to use the equivalent member method for a tapered roof girder.
RFEM 6 includes the Form-Finding add-on to determine the equilibrium shapes of surface models subjected to tension and members subjected to axial forces. Activate this add-on in the model's Base Data and use it to find the geometric position in which the prestress of lightweight structures is in equilibrium with the existing boundary conditions.
This article deals with the determination of the concrete reinforcement for a beam stressed by tension only according to EN 1992-1-1. The aim is to show the tensile load of a member-type element (without imposed deformations) and to define the concrete reinforcement in accordance with the standard's construction rules and provisions using the RFEM structural analysis software.
If you have imported a DXF file in RFEM or you need to add a membrane to an existing member structure, you can use the function "Tools" → "Generate Model - Surfaces" → "Surfaces from Cells", and thus quickly create planar surfaces.
This article deals with elements concerning which the cross-section is subjected simultaneously to a bending moment, a shear force, and an axial compressive or tensile force. However, in our example we will not include loading due to shear force.
When connecting tension-loaded components with bolted connections, the cross-section reduction due to the bolt holes must be taken into account in the ultimate limit state design. This article describes how the design of the tension resistance according to DIN EN 1993‑1‑1 can be performed with the net cross-section area of the tension member in the RF‑/STEEL EC3 add-on module.
Concrete on its own is characterized by its compressive strength. An important part of reinforced concrete is reinforcing steel, which contributes to both the compressive and the tension resistance of the concrete. Welded wire fabric is generally located in the tension areas of the beams or surface elements (hollow core ceiling, wall, shell) to transfer the tensile forces induced by external loading.
When modeling frame structures, RFEM and RSTAB provide various options for controlling the transfer of internal forces and moments at the connection points of members. You can use the member types to determine whether only forces act on the connected members, or whether moments act on them as well. In addition, you can use hinges to exclude specific internal forces from the transfer. One special form is scissor hinges, which allow for realistic modeling of roof structures, for example.
Closed circular cross-sections are ideal for welded truss structures. The architecture of such constructions is popular when designing transparent roofs. This article shows the special features of the connection design using hollow sections.
This technical article deals with the stability analysis of a roof purlin, which is connected without stiffeners by means of a bolt connection on the lower flange to have a minimum manufacturing effort.
When performing structural calculations, the derivation of forces from the roof to the foundations is one of the central tasks of the calculation, in addition to the dimensioning of the cross-sections.
In the existing standard, there were no regulations for the distribution of snow loads for elevated solar thermal and photovoltaic systems on roofs. Only distribution of the loads was advised. It was only with the National Annex DIN EN 1991-1-3/NA: 2019-04 that specific regulations were made for this.
When determining the minimum reinforcement for the serviceability limit state according to 7.3.2, the applied effective tensile strength fct,eff has a significant influence on the determined amount of reinforcement. The following article gives an overview about determining the effective tensile strength fct,eff and the input options in RF-CONCRETE.
Due to the special properties of glass, you also have to pay close attention to the details when modeling in an FE model. Glass has a very high compressive strength and is, therefore, generally only designed for its tensile stresses. One particular disadvantage of the material is its brittleness. Stress peaks that occur in the calculation must, therefore, not be readily neglected.
Buildings often have extensions. If the roof levels are not at the same height, this height difference (if more than 0.5 m) must additionally be considered for the snow load assumption.
The ASCE 7-16 standard requires both balanced and unbalanced snow load case scenarios for a structure's design consideration. While this may be more intuitive for flat or even gable/hip type roofs, the determination of snow loads is increasingly difficult for arch roofs due to complex geometry. However, with guidance from ASCE 7-16 on snow load calculations for curved roofs and RFEM's efficient load application tools, it is possible to consider both balanced and unbalanced snow loads for a reliable and safe structure design.