Structural design documents can be broadly grouped into 2 categories - drawings and calculations. Both are equally important in ensuring a building’s ability to carry its design loads, and both undergo scrutiny during permitting. Once construction gets underway, however, drawings assume a more critical role.
Calculations help engineers determine which structural members and connections are best-suited in a given project. Through calculations, engineers can figure out the strength, stiffness, size, and layout of these elements.
Drawings are the language engineers use to convey a project’s design requirements to contractors. They show the types of members and connections, their locations, and how they interface. The clarity of structural drawings, as well as the level of detail they contain directly impact a contractor’s ability to read and understand what they should be building. Quality drawings reduce permitting revision cycles, help contractors arrive at an accurate estimate, and lessen the risk of Requests for Information (RFIs) and change orders during construction.
Unless your project is relatively minor or cosmetic, you will have to get several permits before work may begin. These may include permits for mechanical, electrical, plumbing, and demolition work, as well as one for the overall project.
Although some permits may be obtained online or over-the-counter with few supporting documents, most permit applications are subject to a plan check review by the Building Department. During this process, building officials assess your project’s compliance with local codes, and the structural design undergoes an evaluation of calculations and drawings. If the reviewers find errors or struggle to understand the drawings, they specify revisions that your design team has to implement before resubmitting the documents. This cycle continues until the officials are satisfied with compliance, possibly delaying your project for months. Submitting clear, accurate, and compliant drawings and calculations with your permit application can help reduce the number of revision cycles, and get your project underway faster.
Before construction starts, your prospective contractors will give you their estimates for the work. These will be based on the drawings your design team issues for bidding, known as a bid set. While these drawings aren’t meant for construction, they should communicate the project’s design requirements effectively. Vagueness and a lack of detail can lead your contractor to miss portions of the scope or overprice your bid. Such inaccuracies can become a major headache when the project’s true construction costs don’t align with your budget. Quality drawings with an appropriate level of detail can help your contractors quote you with better accuracy.
Avoid Extra Costs During Construction
Once construction starts, structural drawings guide the contractor through the selection and installation of members and connections. Imprecise or unclear drawings may lead the contractor to seek clarification via an RFI, or misinterpret the drawings altogether.
RFIs are a formal communication channel between the contractor and the design team. It safeguards against errors but also takes up precious time and resources. Avoiding time-consuming RFIs during construction should be the aim of every design team when reviewing their drawings for accuracy and clarity.
If vague or inaccurate drawings misguide the contractor during construction, the cost and schedule impact of the errors may be severe. Resulting Change Orders - formal procedures for adjusting the contract’s scope, schedule, and budget - may add unexpected costs and jeopardize your project’s completion date.
While many factors may contribute to the need for RFIs and Change Orders, your design team can do its part to avert these obstacles by issuing detailed and well-coordinated drawings your contractor can understand.
How Do We Ensure Our Drawings’ Quality?
1. Leave little room for guesswork
Ultimately, the design team should strive to make their drawings understandable to contractors. They should leave little room for guesswork and confusion by including all critical information on the drawings, showing all dimensions, and excluding irrelevant scope. The notes should be concise, clearly worded, and aligned with the drawings.
2. Include critical details
Details are the enlarged drawings of a specific component of the structure. They are invaluable to builders, as they help them zoom in on the big picture and see the nuances. To serve their purpose well, each detail must be relevant and clear. The project’s design team should provide details for at least the following structural elements:
- slide bearings
- unusual connections
- connections with significant reactions
- critical load path connections
- transfer girder details and connections
- foundation connections
- shear wall details
- critical seismic connections , including hold-downs and chords/connectors
- sloped columns
- secondary bracing details
- spandrel details
- transfer force details
- interfaces with existing buildings
Well-drafted, pertinent details help eliminate conjecture and ensure that the design requirements are executed to the letter. Engineers at Design Everest use an extensive library of details that have proven to be effective on numerous previous projects.
3. Resolve design issues before construction
Addressing issues during the design phase can be done with maximum effectiveness and minimum costs. Conversely, dealing with design issues during construction is more expensive and less effective. To this end, the project’s design team should review drawings to ensure that each discipline’s input is clear, detailed, and works in unison with others.
4. Conduct peer reviews
We all miss things when working closely on something. Things that seem clear to us may be vague and confusing to others. An independent peer review of a project’s structural design is a great tool for spotting errors and ambiguities. The reviewer’s one-of-a-kind expertise may also identify missed opportunities to enhance constructibility and cost-efficiency.
Design Everest Can Help
Quality drawings and calculations can go a long way in making your construction project more efficient. Our team of engineers has 14+ years of experience in the industry, and each of our licensed engineers brings their unique experience to the table. Whatever construction project you have in mind, we can help by drafting clear, detailed drawings and calculations. To find out more, call Design Everest at (877) 892-0292.
- http://www.dvase.org/docs/Breakfast Seminar/Breakfast Seminar oct16.pdf
*Note: The content published above was made in collaboration with members of Design Everest.
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