The Apron Space is the space between the loading platform and the fence line or nearest obstruction. It includes the parking area, where the truck is parked during loading, and the maneuvering area, the space needed to maneuver the truck in and out of the parking area (Fig. 6 and Fig. 7). The minimum recommended center distance between the dock positions is 3.5 m.

The minimum apron space needed depends on the center line distances between the parked trucks at the dock, the length of the trucks, and the steering geometry of the trucks. Also, if the trailers will be parked with the tractors detached, less apron space is needed.

The table below gives the minimum apron space for a typical 40 foot container rig.

We recommend this as the minimum. If the expected trucks are longer than that, increase the space proportionately, e.g. if the dock will handle 48 foot trailers (14.6 m), increase the space from the table by 20%. If the traffic pattern is such that the driver will make an outside turn (clockwise in countries where the driver sits to the left side of the truck), add 15 meter.

If the plant floor is at grade, or has a low grade, recess the truck parking area so that the trailer bed will be at about the same height as the floor (Fig. 8). The parking area will then slope down toward the dock. Ideally, this slope should be 6%, or less. However, if space does not permit, you may increase the slope to an absolute maximum of 10%. Steep slopes force dock workers to load on an incline inside the truck and may cause loads to topple.

Also design drainage for recessed parking areas. As part of this design, the area next to the building should slope slightly away from the building for .5 to 1 m (Fig. 9). A short area is preferable because the position of the trailer’s rear axle will then have less of an effect on the height of the trailer bed at the dock.

If the truck parking area is unpaved or is paved with asphalt, provide a concrete, landing gear pad at a suitable distance in front of and parallel to the dock wall (Fig. 10). This pad is needed to support the trailer’s landing gear when the trailer is parked without its tractor. For a standard 40 foot container chassis, the landing gear is about 10 m from the back of the trailer, for a 20 foot chassis the gear is about 3.5 m. Design a pad wide enough to handle the expected variety of trailers. It is also good practice to extend the pad all of the way back to the loading dock. To sustain a fully loaded trailer, or a partially loaded trailer with a forklift on board, design the pad to support two point loads of 12 tons each, 1.8 m apart.