Dump trailers come in a few basic configurations: semi-trailer end dumps, bottom dumps, side dumps, pups and transfers. While regional weight and axle spacing regulations often determine the best choice for the application, you should be aware of which application each is best suited to perform, as well as advantages and disadvantages.
End dumps handle the tough stuff
End dump trailers allow you to carry larger loads than a standard dump truck, plus offer rapid unloading. They are also capable of hauling difficult materials, such as large demolition debris.
End dumps usually incorporate a heavy-sided design that enables them to handle such abusive material, says Brent Beall, Beall Corp. "When you get into that stuff, they are kind of hard to beat," he states.
A key disadvantage is that they can be unstable when raised in the dump position, especially in applications where the dumping location is uneven or off level.
"With end dumps, you need a really conscientious operator because they are prone to rolling over," says Beall. "You rely on a good operator to know when to dump and where. Even when they are empty and they are lifted, you have a really high center of gravity."
Bottom dumps keep it flowing
Bottom dumps feature a clamshell dump gate on the bottom of the trailer. When the clamshell opens, it allows material to be precisely laid in a windrow left and right, or spread evenly across the rear of the trailer when it opens front to rear.
According to Jim Ladner, Landoll Corp., there are three types of applications for which bottom dumps are widely used: stockpiling, material transport and asphalt paving.
Contrary to common belief, a bottom dump can be an effective stockpiling tool. "When you are truly stockpiling, you have a loader or dozer actually building that pile," Ladner points out. In this situation, a bottom dump offers a very quick turnaround time. "The wheels never stop turning. You actually drive right through that dump zone and open the gates to full open. You can dump an entire 21-yd. load in about 25 ft." The material can then be easily handled with the loader or dozer.
With cross-gate models, you can easily spread materials on roads. "We have found that driving at certain speeds, it will actually dump a load as wide as 16 ft. and do a nice job of flowing that material out," says Ladner.
They're also a popular choice for laying a windrow of asphalt in front of a paver laydown machine, since they can help produce a higher quality mat with fewer seams.
"Each time a new dump truck backs up to that asphalt machine, it has to stop, so there is always a seam," Ladner explains. "If the time between trucks is several minutes or longer, then you have quite a seam that builds up." This can result in weak spots in the pavement.
With a bottom dump, there is no need to stop the laydown machine. "It is basically a continuous flow of asphalt," says Ladner.
Dean Word Co. has seen the benefits of this first hand. The highway/heavy road, bridge and paving contractor based in New Braunfels, TX, also operates its own quarry and asphalt plants.
Keeping asphalt flowing between the plants and paving operations is a fleet of 53 belly dump trailers. According to Tim Word, these trailers increase the quality of the mat by laying a constant windrow of material in front of the paver.
"You can keep the laydown machine steadily moving," he notes. "You don't have starts and stops. You get a little improvement in mat quality and a little reduction in segregation. So the overall quality is as good or better than you can achieve any other way."
Of the company's bottom dump trailers, 39 are Landoll models. "We are running maximum interstate loads of 80,000 lbs.," says Word. "At the time I started with Landoll, they had the lightest unit on the market. They are very lightweight, which is extremely important."