Nolan Hill Daycare

For the design of connections between the columns, beams and bracing in the system, a welding method was selected instead of the conventional cutting and slotting method, such that the column would be welded to the gusset plate connecting the beam and column. This connection type was selected to reduce future maintenance requirements. The cutting and slotting method would lead to more complex maintenance procedures that would require removing the entire connecting and reinstalling it, whereas the welding connection would only require the welded element to be replaced. Additionally, the welding method -unlike the slotting method -would not change the effective net area of the bracing members, ensuring the connection’s ability to resist forces.

After conducting research and performing a preliminary analysis, the team decided to proceed with structural steel for the above grade structure of the building. Steel’s ability to withstand loading under long spans with minimal deflection due to its high load-to-weight ratio makes it an appropriate material choice for this structure. Additionally, given steel’s light weight characteristic, steel buildings are generally lighter than their concrete equivalents. This decreases the forces being transferred to the foundation, resulting in a smaller foundations design and therefore reduced amount of material required.

.STRUCTURAL STEEL SUPERSTRUCTURE

Braced frames were selected as the lateral load resisting system (LLRS) for this design. Such braced frames better resist lateral displacements compared to their rigid frame equivalents and results in smaller column sections, providing a cost-saving opportunity. The design of the braced frames accounts for tension and compression characteristics and pin-pin connections only, allowing for a repeatable design process and efficient fabrication. Additionally, tension compression systems allow braced frames to be fully ductile compared to tension only braced frame systems. Construction of these braces would be straightforward for the typical contractor, resulting in a more accurate assembly on site while providing a cost-effective construction of this system. The architectural layout for this building offers adequate areas to build and hide the cross braces within walls, providing the client with more flexibility with how the space can be utilized, including the aesthetics of the building. These reasons make braced-framed systems the most popular LLRS type in Canada and the first option that is considered when designing the structural system for a building.

There are several types of shallow foundations, and a combination of strip and pad footings were selected for design. Pad footings are utilized to support columns and as such were selected for interior and exterior column support of our building. These types of footings are mostly placed concentrically beneath the columns, which is the case for the interior columns. However, due to property line constraints, uni-axial and bi-axial eccentricity were considered for the exterior columns. Comparable with a pad or spread footing is the strip footing, with the main difference being that this type of footing supports a wall along its length. A combination of strip and pad footings were designed for the building perimeter.

Appropriate design practices and procedures were implemented throughout this project, to ensure a safe design. This was achieved by ensuring adherence to the building codes and design handbooks. When determining the loads and checking against deflection, the National Building Code of Canada 2015 (NBCC) and the National Building Code of Canada – Alberta Edition 2019 (NBCC-AE) were utilized. In the design of the superstructure and substructure, the Handbook of Steel Construction (CSA S16-14) and the Concrete Design Handbook (CSA A23.3-14) were used respectively. Relevant course material was used in conjunction with the codes and handbooks mentioned, in order to aid in the application of theoretical concepts during the design process.

A braced structural steel system was assessed to be the most feasible option for our application of a daycare as it yields the lowest cost while meeting the structural requirements of the building. Given that the residents of the Nolan hill community will ultimately incur the costs, the group had to ensure the design of the daycare would meet the needs of the community while being affordable to the those accessing the services. For the cost analysis, the structural drawings were sent to a local trade for their budget on the supply and install of the structural steel system. A Class-D estimate was performed for the concrete foundations with the help from a general contractor who builds and prices similar projects to the Nolan Hill Daycare. The structural steel budget was estimated to be $500,000, and the concrete foundation estimate was $196,000, giving an overall cost of $696,000. Additionally, the performance of steel as a material, such as it’s high durability and insulating properties result in minimal maintenance and repair costs over its lifetime making it the best option for the design. The following table summarizes the cost of the project.

Although steel and other materials faced shortages and longer than expected procurement times due to COVID-19, Alberta is home to western Canada’s largest steel fabricator, Supreme Group. As the effects of the pandemic lessen, and companies strategize to solve material availability issues, steel is once again becoming readily available. With nearby steel manufacturers available, local shops will be supported with the recycling of cash flow within the local economy. Not only will society benefit from a financial standpoint, but also on a social and environmental level.