Structural System Strategy & Features
For my project, I selected a glulam (glued-laminated timber) structural system using Western species glulam beams. My decision was guided by sustainability, buildability, and architectural integration with my design goals. Glulam is a renewable, low-carbon alternative to steel or concrete while offering the necessary strength for larger spans, particularly in the atrium and roof areas.
Since my building includes a mix of open spaces, curtain walls, and a green roof, I structured the framing system to support these varying conditions efficiently. The structural system is mostly hidden within the floor assembly, ensuring a clean architectural experience without exposed framing, while still providing stability and strength.
Material & Framing System Selection
I opted for a glulam beam system with light-frame wood joists for typical floor areas, ensuring a balance between strength, cost-efficiency, and sustainability. The main framing decisions include:
- Standard Floors: Light-frame wood joists at 16” O.C., supported by glulam beams.
- Atrium: Wider-span glulam beams spaced ~10' apart to maintain an open, column-free space.
- Curtain Wall Areas: Additional support beams aligned with structural grids to handle lateral loads.
- Roof (Green Roof + Sloped Glazing Section): Heavier glulam beams spaced closer (~12” O.C.) to support soil load, snow accumulation, and glass structure.
This system allows for flexibility in floor layouts while ensuring structural integrity.
Structural Columns & Major Framing Locations
Given the 50% curtain wall coverage, I minimized the number of interior columns by relying on strategically placed glulam beams and lateral bracing at key locations.
- Structural Columns: Located primarily at the building perimeter and grid intersections, ensuring efficient load distribution.
- Major Beams & Framing Elements:
- Glulam beams embedded within the floor system for structural efficiency.
- Atrium beams: Large-span glulam members aligned with the grid for maximum openness.
- Roof framing: Strengthened to support the green roof’s soil & plant load, as well as the sloped glazing section.
Structural Challenges & Solutions
Atrium Open Space:
- Required long-span glulam beams (~10’ apart) to minimize interior columns.
- Grid layout was adjusted to align beam placement with staircases and elevator shaft constraints.
Green Roof Load Considerations:
- Use closer beam spacing (~12” O.C.) to handle the additional soil weight.
- Ensure waterproofing and drainage layers are accounted for in the structural strategy.
Sloped Glazing Over Atrium:
- Needed reinforced roof beams beneath glazing to support wind and snow loads.
- Ensured thermal movement and snow accumulation were considered in the beam layout.
Curtain Wall Stability:
- Additional structural supports were placed at curtain wall intersections to ensure lateral stability without interfering with the open façade design.
