One of the more popular applications for BoltHold asphalt anchors is to secure a carport to asphalt. Pictured is a metal framed carport, shown without side walls.

A common question is how to estimate the forces on the structure and which anchors to select.

First we need to establish that the carport is self supporting -- it will stand proudly as long as no external forces are applied (such as wind, your kids bumping into it, and the like). If it is not self-supporting, you might not wish to install it on asphalt because it will require guy cables/lines to keep it up, and these are under constant pull. Asphalt is very good at resisting temporary forces, but not at sustained pressure or pull. (That is why one can not use expansion anchors in asphalt, as they exert continuous force against the walls of the hole and the asphalt will yield in a matter of days.)

A self-supporting carport needs to resist winds. Winds of 50 MPH generate a force of about 10 lb/sf. That translates to a force of 320 lbs per 8x4' panel. A 100 MPH wind will exert 1250 lbs of force on the panel. The forces the wind create on the carport depend on its direction and the geometry and material used in the carport. It is thus best to over-design the anchoring.

Using our SP10 6" long anchors, we recommend placing the anchors linearly along each of the walls at a spacing of not more than 16 inches for an 8' high structure. If you use 2 anchors per post, you can space them 32 inches. Unless you can separate the anchors by 12" placing more than 2 anchors per post is not effective, as the asphalt strength depends on its area, and anchors crowded in a small area share the same asphalt area.

For 10' high structures we recommend the use of the SP12 or SP18 12" long anchors.