What is a Belly Dump?

bellydump -on -asphalt

A belly dump is a trailer that is seen on almost every road building job.  The name is is pretty self explanatory.  They are also known as bottom dumps.  The main body of the trailer where the material is loaded is known as the tub.  There are typically two large gates,that make up the entire bottom of the tub.  Large air cylinders push the gates open.  The cylinders also move the gates up the sides to get them out of the way as you dump.  These trailers are usually dumped on the move, creating a windrow.  A windrow is a long row of material dumped on the ground that is easier for graders (tractors) to move on the jobsite, than a pile.  The gates can open to different widths to adjust the size of the windrow.  These workhorses of the construction world are the major material mover when building roads.  They are essential to getting the material ( rocks, dirt and asphalt) from a pit to the jobsite.  Next time you go through a construction site, look for them.  Be sure to stay back from them.  When material is dumped in the top, sometimes the loader will drop material onto the truck and trailer.  This can fall off as he is driving.  Most drivers are very careful to brush off any piles on the truck, but there is always the possibility of missing some.


If the hauling is all onsite, they will sometimes use these off road haul trucks with belly dumps.  They are too heavy and slow to be in traffic, but can go into more extreme conditions than a typical on road truck.


When they hook two trailers together like this it is called is a belly dump train.  Sometimes these are used to haul extra material.  Sometimes they are used because the jobsite won’t allow long trailers to maneuver on site.

bellydump in river

Here is a bellydump used in the wrong way.  Belly dumps are used to build roadbeds, NOT riverbeds…this guy is sooo confused.

I hope this helps you recognize these great trailers.  We have a bellydump.  I enjoy watching it work.  It is fun.

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