JAMAR Technologies TRAX I, Руководство пользователя

Страница: 29 / 64

3-3
installed over two lanes (24 feet), but since they are 50 feet long,
you will still have 26 feet back to the TRAX I. For round tube, the
lengths would be 48 feet for the short tubes and 60 feet for the long
tubes. It is very important that the air pulses travel over the
same distance when two or more tubes are used to record data.
To accommodate the required length of tube, brass splices may be used.
The splices are approximately three (3) inches long, hollow and do not
restrict the flow of air. Do not use the splices on the roadway itself,
only on the section of tube after the clamp nearest the TRAX I.
Tube Placement
Tubes should be placed exactly perpendicular to the flow of traffic to
prevent double counting. When using two or more tubes that must be
set at specific distances from each other, always use a tape measure or
ruler to measure from the center of each tube to determine the proper
spacing. In short tube, long tube setups, the short tube should be in-
stalled to the zone line (center of the highway). Observe traffic to be
sure that vehicles in the outer lane are not coming in contact with the
short tube.
Installation
Round Tube (.25 ID x .60 OD)
Round tube should be stretched one foot for every ten feet of road-
way when being installed. Each tube should be secured at each end
of the roadway by using a galvanized C-Clamp, Chinese Finger,
Figure 8 Grip or an End Plate. Whichever is used, ensure the proper
nail size is used. Use the longer nail size (normally 2 1/2 inch or
longer) in hot weather due to the softness of the asphalt. In cold
weather applications, the asphalt becomes harder, making it more
difficult to drive in the nails. In this situation, smaller nails (1 1/2
inch) can be used.
Next, secure the tube on the traveled portion of the road surface by
using mastic. As a minimum, one piece of mastic should be placed
on the zone line (middle of the road) and two pieces of mastic
should be placed in the middle of each lane. Additional mastic
should be used as deemed necessary to prevent the tube from mov-
ing when stuck by a vehicle.
Chapter 3 — Road Tube Installation