Question

The proportion of glass used when planning a building is increasing. Open, light-flooded buildings represent the modern art of architecture. However, specialized engineers have to face new challenges during planning. One such example is ceiling-high glass facades loaded by a handrail. The influence of this loading, as well as the calculation of the deformation, are shown in this article.

Loading panes of insulating glass due to climatic effects are clearly regulated in DIN 18008. In the case of the corresponding pane geometry, this load type can also govern for the ultimate limit state design. The FE design on the entire structure with the space between panes represented as the volume of a gas provides exact results for the analysis. However, a plausibility check is also becoming increasingly important. This article shows various options for performing these checks.

As mentioned in Part 1, according to the current standard DIN 18008-3, it is allowed in glass construction to represent point supports for glass components by means of FEM in order to design the adequate ultimate limit state. The rules are described in Annex B of the standard [1].

In the add-on module, select the surfaces to be designed (for example, by using the Select function). The geometry of the glass pane, as well as the loads, is imported from the RFEM model.

Then, you have to decide if the calculation should be performed without the influence of the surrounding structure (local calculation) or with consideration of this influence (global calculation). If you select the local calculation, each surface selected for the design is detached from the model and calculated separately.

The global calculation considers the entire structure, including entered glass panes. All glass composition data and glass properties of individual layers are to be defined in RF-GLASS input windows. You can select layers of type glass, foil, and gas. The desired material can be imported directly from the library, which contains a large number of materials.

All parameters of individual layers, including their thicknesses, are editable. In addition, you can create a number of compositions in RF-GLASS, allowing you to design different types of glass together.

For insulating glass, you can consider external loads as well as loads due to temperature, atmospheric pressure, and altitude changes for the analysis. The module calculates these loads automatically on the basis of climatic load parameters. If you select the local calculation type, it is necessary to define line supports, nodal supports, and boundary members of the surfaces in RF-GLASS. These supports and members are considered in RF-GLASS only and have no influence on the model created in RFEM.

After the calculation, the results are displayed in clearly arranged result windows. Thus, you can easily find the maximum stress ratio. The stress diagram by composition is displayed as well.

Furthermore, RF-GLASS displays a parts list and, for insulating glass, the gas pressure. It is possible to display the results graphically in the RFEM model.

Both input and result tables of RF-GLASS, including graphics, can be added to the RFEM printout report. In addition, it is possible to export all tables to MS Excel.

• Design of single-layer or laminated glass as well as gas layer insulating glass
• design of curved glass
• Option to select either local calculation without regard to the influence of a surrounding structure, or global calculation with regard to the influence of an entire structure
• Calculation of limit stresses according to DIN 18008:2010-12 or TRLV:2006-08
• Assignment of loads to load duration classes
• Extensive material library including all common glass, foil, and gas types in compliance with the DIN 18008:2010-12, E DIN EN 13474 standards, and the TRLV:2006-08 regulation
• Optional consideration of shear coupling of layers
• Consideration of climatic loads
• Calculation according to the linear static analysis or nonlinear analysis according to the large deformation analysis. analysis
• Stress analysis, ultimate limit state design, serviceability limit state design
• Graphical representation of all results in RFEM
• Possibility to filter results and color scales in result tables
• Direct data export to MS Excel