Sophia KianniYour Design Journal entries this week should highlight your design thinking that influenced your decisions about:
- your overall strategy and the features of the structural system
Steel framing, with concrete foundation, looking to have a span as large as possible, and make the structure a feature of the monolithic, industrial and naked design of the building
- the material and framing system selected
All the building was done in structural steel framing, along with concrete foundations
- the locations of structural columns and major framing elements
All columns placed in a gridline folowing the contours of the building, as well as the main features like the hallway and elevator/stair core
- any special structural challenges
The building is quite open, so it was a challenge to connect all columns with beams while keeping them out of the atrium
- Embodied Energy & Carbon Footprint Steel: High embodied energy due to extraction, processing, and manufacturing, but it is highly recyclable (over 90% in construction). The production of new steel, especially in electric arc furnaces, is becoming more energy-efficient. Concrete: Lower embodied energy per unit than steel, but cement production (a key component) is one of the highest CO₂ emitters globally. However, innovations like carbon-capturing concrete are improving its environmental profile.
- Availability & Local Sourcing Steel: Readily available in NY due to established supply chains and proximity to steel mills. Prefabrication off-site reduces construction waste. Concrete: Also widely available, with many local plants minimizing transportation energy. However, sourcing sustainable aggregates can be a challenge.
- Construction & Energy Efficiency Steel: Faster and more precise construction reduces labor energy use. Steel frames allow for better insulation placement, reducing heating and cooling costs. Concrete: Has high thermal mass, which helps regulate indoor temperatures, reducing HVAC energy demands. However, its curing process is energy-intensive, especially in cold climates.
- Durability & Maintenance Steel: Long-lasting but requires maintenance (corrosion protection in humid environments like NYC). Concrete: Extremely durable, low-maintenance, and naturally fire-resistant, but subject to cracking and requires repair over time.
- Structural Efficiency & Space Utilization Steel: Allows for lighter, taller structures with more flexible designs, reducing material use. Concrete: Heavier and bulkier, which can mean increased material use and higher energy demands in transportation and installation. Conclusion For a building in NY, steel tends to be more energy-efficient when considering:
Faster construction reduces energy expenditure. Recyclability lowers lifecycle energy consumption. Structural efficiency leads to less material waste. Flexibility in insulation improves operational energy efficiency. However, concrete’s thermal mass is an advantage for passive heating and cooling, reducing energy consumption in certain applications. A hybrid approach (steel structure with concrete elements like slabs) might provide the best balance of efficiency, sustainability, and performance.