For concrete deck scales, a concrete crew of three or four can normally pour, finish, and seal-cure the concrete deck surface of a 70′ scale in 2 – 3 hours. (Don’t forget, standard concrete reaches full strength after a 28-day curing period. At seven days, standard concrete reaches approximately 75% of its maximum strength and can handle moderate loads.) Final wiring connections can normally be completed the same day while the concrete is curing.  Please note these are just rough estimates and times may vary depending on many factors.

Inspect load cell cables for damage. If damage is present, the seal is probably degraded as well. To combat this problem, some manufacturers offer rigid or flexible metal conduit to run the cable through, providing a layer of protection that’s nearly impervious to damage from rodents. Even though steel over braid cable provides more protection from damage than cable sheathed with polyurethane or plastic, they still need to be checked as well.

Weather is another enemy of load cell cables. When exposed to moisture, cables can become wicks. Water can be sucked through the cable’s length by capillary action until it enters the load cell or junction box. Once inside, it can damage components and seep into the inner layer of the cable. Wet cables may not cause signal distortion immediately, but they may slowly corrode the copper wires or shield beneath the insulation, causing big trouble sooner or later. Corrosion of the shield limits the cable’s effectiveness in blocking electromagnetic interference (EMI) and radio frequency interference (RFI). Corrosion of individual wires will degrade the signal. If you discover a wet home run cable or load cell, replace it. To help prevent moisture from entering the cell from the cable, bend the cable or flexible conduit downward to create a drip loop at the location just before it enters the cell.

Check the junction box (j-box) for internal condensation, is the most common moisture problem. This occurs from normal air exchanges from heating and cooling cycles, and over-aggressive washing that damages sealing components that haven’t been properly maintained. If left unchecked, wiring terminals and other components in the enclosure will corrode. Due to its material properties, a stainless steel j-box is more vulnerable to internal condensation. If stainless steel is not required, install a j-box with a fiberglass-reinforced polyester (FRP) enclosure. A desiccant bag in the enclosure will help control moisture.

Unlike check rod binding, bumper bolt displacement is easy to spot.  Bumper bolts need to be tight so they don’t move on their own, yet maintain clearance when the scale is both empty and loaded.  Seasonal temperature and weather changes can cause concrete and steel to expand and bumper bolts can bind tight against the contact area.  If binding occurs, adjust bumper bolts to maintain proper amount of clearance for all conditions. Rice Lake SURVIVOR scales do not have bumper bolts.

Binding is a common cause of inaccuracies. A rock as small as your big toe can become wedged between the foundation and deck.  Installing T-Strip molding between the deck and foundation can help keep debris from getting caught or falling down into the scale. Some above-ground scales have end cleanout plates that can be removed, allowing access to clean out debris that builds up on the foundation’s surface closest to the scale’s end.  The above examples are a great reason to contact an experienced truck scale sales and service company like Central Carolina Scale for your truck scale needs.

When deciding how often to have your scale tested, take into consideration your number of weighments, climate and the value of the product being weighed.  Aside from the actual calibration, most of the inspection will consist of you or your scale technician conducting a visual inspection of the scale, foundation and surrounding area.  Every vehicle scale should be calibrated and tested by a state-licensed servicing agent with no less than 25,000 pounds of certified test weights.  A lot of times it is ideal to use a company like Central Carolina Scale in Sanford, North Carolina  that has a scale test cart that can test different areas of the scale.

Once the scale sections have been correctly adjusted, the final step in the calibration process is the span setting. Here the weight display is adjusted to read the exact value of the test load applied to it. Additional testing takes place by checking the weight display with increasing and decreasing loads to make certain the scale is linear. After successful completion of the calibration process, the scale service technician will apply security seals to all of the adjustment access points to prevent further adjustment. In the US, the scale will be tested to NIST Handbook 44 Class IIIL tolerances.

After the truck scale has been calibrated & sealed by the scale company, it will normally be tested in the presence of a state or local weights and measures inspector who will verify its proper operation and in-tolerance readings. In some states, the local scale service technician is licensed by the state to perform this function. In either case, once the scale has been officially tested and a report completed, a sticker will be placed on the digital weight indicator attesting to that fact and a copy of the test report sent to the state department of weights and measures for filing. You, as the scale owner, should also receive a copy of this test report for your records.

A 70′ long scale must have a minimum of 25′ long ramp and the approaches must be 10′ long for a total of 35′. This equates to a total length of 140′ needed for a 70′ long above ground truck scale. Check with local and state regulatory agencies for required approach lengths in your area.

Pier or Slab Foundation
With an above ground installation, you will have a few foundation options.

Deep Pier
Typical for the northern areas of the United States, the deep pier foundation places part of the foundation below the frost line to eliminate the negative effects that freeze-thaw conditions create with foundations. Similar to the isolated pier foundation, the deep pier foundation also requires 3000 PSF bearing pressure.

Full Slab
A full slab foundation is a continuous or monolithic pour of concrete that runs the entire length of the weighbridge. This is the second most cost-effective type of foundation and is designed for ground that has a soil bearing pressure of at least 1500 PSF.

Pit-type
The pit foundation comes in numerous depths from 2′ to 6′. Your pit depth should best fit your needs and meet all federal, state and local requirements.