A building’s structure - the foundation, exterior walls, interior load-bearing walls, floor, and ceiling joists - can make up 30% of total construction costs. Your building’s architectural elements largely determine the structure’s cost-efficiency; keep this in mind when you decide on features such as large windows and open concept spaces. When envisioning a new structure, engineers often have to balance design choices against the environmental impact of materials used. It is estimated that 40 to 50 percent of greenhouse gases are produced by the construction industry, according to the California Integrated Waste Management Board. Lessening the impact of construction on the environment is a work in progress. Structural engineers face the challenge of designing structures that can support not only the weight of the structure itself but other loads as well, such as forces caused by people, furniture, snow, wind, and earthquakes. The structural framing system should be designed to carry these loads in an efficient manner. Because the cost of construction materials used to build a structural system is often based on the weight of the materials, it is cost effective to use the least amount of material necessary to provide a structure that can safely carry the applied loads. The most efficient structures are strong and lightweight. One measure of the cost effectiveness of a structure is structural efficiency. Although structural efficiency can be defined in many ways, in this aspect we will define structural efficiency rating as the ratio of the load applied to the structure to the weight of the structure itself.
It is important to understand that in this definition, the maximum design load applied to the structure is not necessarily the maximum load that the structure can carry. In order to provide an efficient design, the structural engineer must design the structure to carry the loads that are anticipated to occur, called the design load. So efficiency is based on maximum design load, not on the actual load that the structure can carry, which may be much higher than the design load. Of course, often the most efficient structure will be one that has a maximum capacity equal to the maximum design load
1. Avoid Large Openings
Floor-to-ceiling windows soak your home with natural light and offer stunning views, but the openings they create often require costly seismic and wind bracing mechanisms, such as prefabricated shear walls or steel moment frames. To avoid incurring potentially crippling expenses, opt for smaller windows and use skylights to maximize natural light in your home.
2. The Problem With Large Open Spaces
Open-concept floor plans are popular for valid reasons - more daylight, improved space functionality, and better sightlines. If you plan on having an open-concept space in your home, however, keep in mind that the expansive living area they create leaves the floor above in need of specialized supports. These can take the shape of Laminated Veneer Lumber (LVL) or steel beams, sometimes with columns, all of which cost more than a load-bearing stud wall.
Besides large windows and expansive open spaces, try to avoid complex features like vaulted and coffered ceilings - these can also add a substantial premium to your home’s structure.
How We Can Make Your Design Cost-Efficient
Whether you are remodeling, renovating, or planning new construction, our team will design your project with cost efficiency in mind. Our engineers know where to find compromises that help you get the savings you want.
1. What factors could affect the choice of materials for the structural frame of a building? cost, location, strength, form, height.
2. Is it advisable to compare the Structural Efficiency Rating for two different proposed framing systems for a building if one system uses structural steel framing and the other uses castin place concrete? Why or why not? If not, what would be a better comparison to determine efficiency? No, they are used for different purposes. Things should be determined by efficiency rating not the maximum load capacity.
3. Why would a structural engineer be more interested in the Structural Efficiency Rating using the maximum design load than the efficiency determined by using the maximum load capacity of the structure? Its better to use efficiency because a structure should be used to withstand its purpose not to meet the maximum load capacity.