Haus Gables in Atlanta, GA USA
Haus Gables, a new ground-up residential project designed and developed by architectural designer Jennifer Bonner, director of MALL, has recently completed construction in the Old Fourth Ward neighborhood of Atlanta, Georgia.
Jennifer Bonner from MALL, USA
Fire Tower, USA
AKT II, United Kingdom
PEC Structural Engineering, USA
The 2,200-square-foot home is one of only two residences in the country made of cross-laminated timber (CLT), a durable wood material produced by gluing together layers of lumber that alternate in direction.
The stimulation of Haus Gables had Bonner asking: "What if you blurred the lines between real architecture and the media and methods used to simulate it, namely drawings and models?" The project required the work of four engineers including specialists in CLT. The heaviest panels weigh 3,500 pounds, yet all of them were craned into place in just 14 days. The remaining construction took about a year.
This single-family home adjacent to the Atlanta Beltline, a former railway corridor around the core of Atlanta, is a two-story, two-bedroom house assembled from 87 cross-laminated timber (CLT) panels bolted together with 12 inch screws. These massive custom-milled panels, up to 9.5 inches thick and 34 feet long, provide both structure and interior surfacing.
A cluster of six gable roofs are combined to form a single roof. In an attempt to rework spatial paradigms of the past, such as Le Corbusier’s free plan and Adolf Loos’s raumplan, Bonner offers the roof plan as a way to organize architecture. Here, the roof plan establishes rooms, catwalks, and double height spaces in the interior by aligning these spaces to ridges and valleys in the roof above. In this case, the floorplan is a result of the roof.
Two of Dlubal Software’s valuable customers were involved in the design of Haus Gables: Bensonwood and Fire Tower Engineering. Bensonwood first created a DXF file based surface model using their timber specific fabrication CAD model. Fire Tower then took this model, added loads, and ran an in-depth analysis.
Both engineering firms worked together to gather information from the structural model for the foundation engineer to design the podium as well as for Bensonwood to detail the screw and other timber connections. Special consideration was needed to orient the screws and bearing surfaces with respect to the anisotropic properties of the timber.
Using the RF-LAMINATE module within RFEM, CLT capacities and stiffnesses were verified which was critical to the success of the project. This held especially true when the CLT manufacturer (species and layup) changed midway through the design process.
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When designing many members in one design case, it is sometimes difficult to recognize the governing designs. To improve the overview and to display the relevant designs in a compact way, you can use the filter options under the result tables. These are included in all design modules of steel, aluminum and timber structures in RFEM and RSTAB.
RFEM/RSTAB add-on module RF-/JOINTS Timber-Timber to Timber | Design of direct timber connections according to Eurocode 5
3D-Modell und Foto vom Seilspielgerät „Globe“ (© Screenshot: Dipl.-Des. Heinz Bornemann, Bad Bentheim/© Image: Berliner Seilfabrik)
3D-Modell und Foto einer „Tetragode“ (© Screenshot: Dipl.-Des. Heinz Bornemann, Bad Bentheim/© Image: Berliner Seilfabrik)
Side view of the timber and steel structure of the airship with the 'umbrella' membrane (© Jan Slavík, DOX)
Buildings made of cross-laminated timber (CLT), glued-laminated timber and OSB panels modeled with the RFEM program
- General stress analysis
- Graphical and numerical results of stresses and stress ratios fully integrated in RFEM
- Flexible design with different layer compositions
- High efficiency due to few entries required
- Flexibility due to detailed setting options for calculation basis and extent
- Based on the selected material model and the layers contained, a local overall stiffness matrix of the surface in RFEM is generated. The following material models are available:
- Hybrid (for combinations of material models)
- Option to save frequently used layer structures in a database
- Determination of basic, shear and equivalent stresses
- In addition to the basic stresses, the required stresses according to DIN EN 1995-1-1 and the interaction of those stresses are available as results.
- Stress analysis for structural parts of almost any shape
- Equivalent stresses calculated according to different approaches:
- Shape modification hypothesis (von Mises)
- Maximum shear stress criterion (Tresca)
- Maximum principal stress criterion (Rankine)
- Principal strain criterion (Bach)
- Calculation of transversal shear stresses according to Mindlin, Kirchhoff, or user-defined specifications
- Serviceability limit state design by checking surface displacements
- User-defined specifications of limit deflections
- Possibility to consider layer coupling
- Detailed results of individual stress components and ratios in tables and graphics
- Results of stresses for each layer in the model
- Parts list of designed surfaces
- Possible coupling of layers entirely without shear
- In RF-/TIMBER AWC and RF-/TIMBER CSA, I receive the error that says torsion limit exceeded. How do I bypass this error message?
- Why is the strength always reduced by the kmod value of 0.6 during the calculation in the RF‑LAMINATE add‑on module, although I have load combinations with variable loads?
- Can I consider a reduction of the stiffness according to the German regulation NCI NA.5.9 in TIMBER Pro?
- I have selected all available members for design in RF-/TIMBER Pro. Why are tapered members not designed?
- When performing the fire resistance design with TIMBER Pro, I get the error 10001. How can I fix the error?
- Is it possible to set user-defined values when viewing solid stress results?
- How are the signs for the release results of a line release and line hinges interpreted?
- How can I create a curved or arched section?
- Is it possible to design the support pressure or the compression perpendicular to the grain in RX‑TIMBER?
- After the design with RF‑/TIMBER Pro, I optimized a cross-section. Why is the utilization of the optimized cross-section exceeded now?
Programs Used for Structural Analysis
Structural engineering software for finite element analysis (FEA) of planar and spatial structural systems consisting of plates, walls, shells, members (beams), solids and contact elements
Deflection analysis and stress design of laminate and sandwich surfaces
Design of steel members according to the American standard ANSI/AISC 360