Parking garage, lots and transfer beam

Hi I got this question and the answer is transfer beams, can you explain what a transfer beam is? I thought it’s a heavy concrete beam. Also with parking lot and garage questions I think the idea is to use ibc to reference how many spots are needed, how do you go about parking lot and garage questions? I have the studio companion and it mentions parking lot structures, helix parking and split level.

The layout for a new 8-story concrete apartment building is planned with 20-foot by 20-foot structural bays. A parking garage with two-way traffic and 90-degree stalls will be located on the ground level and 1.5 subterranean levels.

What is needed at the parking garage to make the layout work for vehicle circulation?

Hi @sergioclaure93 ,

A transfer beam is a large beam which collects multiple loads from above and transfers them down to supports. Here’s a handy online article I found that explains them further in really understandable way: What is a Transfer Beam? . It can certainly be made of reinforced concrete, as it likely would be in a parking garage, but there’s no specific material a ‘transfer beam’ must be. “Transfer beam” is a name given to a beam based on it’s function, not it’s material.

So, when you’re looking at a parking garage, drive aisle widths are going to be a huge consideration. You don’t want a column in the middle of a drive aisle! With two-way traffic and 90-degree stalls you know you’re going to need a significant drive aisle. This drive aisle is going to be larger than 20’ certainly. So, you know you need to transfer the loads of some of the columns to a wider bay to allow for the drive aisle. Therefore, you need a transfer beam to take those loads and re-distribute them.

Here’s an example of a drive aisle requirements I found online. This is the city of Los Altos California requirements for drive aisles and it does a good job of showing how large they might need to be in a given situation!

Hope this helps!

@coachchrishopstock can you please look into this question to make sure the listed references are up to snuff?


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Ok so a transfer beam avoids the use of columns at certain areas cause it’s a function, I get the drive aisle too that was very helpful thanks.

Hey @sergioclaure93 - glad that @coachdarionziegler was able to help you get to the bottom of this!
I looked into this question and agree that it’s up to our standards. The main point here is that the 20x20 structural grid above would not allow for 90 degree parking stalls with a drive aisle, therefore a means to transfer the weight from the 20x20 grid to a wider grid would be required. A transfer beam is the only option listed that can accomplish this.

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