Glulam Building: Start to Finish – Part Two
Welcome to our “Glulam Building: Start to Finish” series. Our goal is to provide an overview – from idea to completion – of a glulam building, from the perspective of a glulam manufacturer and designer.
Part 2: Design
Once the idea of a building is set, the next step is general design. Over the course of the next few posts in this series design will be presented as a list of steps. Nothing is every that simple and design is typically iterative, so this is an idealized version of this process. First set the load criteria…
Part 2A: Loading
- Dead Loads: These are permanent loads on the building due to its own weight. Some of these (the self weight of structural components) will of course change as the building design is finalized. But other common “superimposed dead loads” (weight of roofing, insulation, electrical and mechanical systems, walls, flooring, ceiling) typically won’t change.
- Live Loads: These are the vertical loads caused by the environment and occupancy of the building and are set by the Building Code. Occupancy loads are determined by the use of the structure, for example floors in a typical homes have a residential live load of 40 psf (pounds per square foot). Environmental loads are determined by the location of the building and include snow load and vertical wind loads on roofs. **
- Lateral Loads: These are horizontal loads caused by the environment, again determined by the building’s location. Wind and earthquakes cause lateral loads. **
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**Note that wind loads appeared in both the Live Loads and Lateral Loads sections. The vertical and horizontal forces due to wind aren’t always split this way, but in next week’s discussion on Lateral Systems we’ll see why this can be helpful.
Deflection – In the design process loads will be used to verify the strength of the structural components, and to check their deflection. Therefore, deflection criteria should also be set during this first step, particularly if a building will have brittle finishes or sensitive equipment that might require more stringent deflection limits.
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If the Engineer of Record (EOR) for the project is not the glulam designer, i.e. if the engineering of the glulam components is delegated to the glulam manufacturer, they should provide the loads and deflection criteria as soon as possible. The EOR will ultimately be responsible for confirming the load and deflection criteria used, so providing them at the beginning can help avoid potential conflict later in the project.
Next week we’ll delve into lateral design and requirements.
If you’d like to discuss the design process for your glulam building contact us at 607-369-9341 or email us at [email protected]