What is long beam trailer
Long beam trailer is a kind of trailer set to transport long cargos by loading two ends of them, which is the most effective and economical way to transport long cargo like steel structure, long steel pipe, precast concrete beam and long bridge section.
The trailer set has two trailer modules, the front module could be towed by a prime mover or self-propelled. Rear modular is like a steering dolly, could be equipped with a small diesel engine to realize manually steering.
Long beam trailer is supporting launching girder to construct bridges, it fulfills the transport job between precast concrete bridge section yard to bridge construction site.
The vessel or beam should be strong enough to connect two modules of trailer or SPMT.
How to choose suitable equipment to transport long beam/vessel
- Long beam trailer – which has no power source for moving, but has a small engine to power steering, mechanical suspension, the most economical way for transporting long beams
- Modular trailer – which has hydraulic suspension to protect beam and vessel in a better way
- SPMT – If beam or vessel is too heavy, and space is too narrow for steering, SPMT is the best way to transport them by virtue of its minimum turning radius. And both modules can be synchronized for moving and steering, hardly any torsion on the beam and vessel. If the transport job is a routine x 24, AGV(automatic guided vehicle) SPMT is available
- Self-propelled long vessel trailer – an upgraded type of long beam trailer, mechanical transmission for moving, please see below chapter for detailed info
Self-propelled long beam trailer
It has functions of beam transport and feeding. Front trailer and rear trailer all equipped with power sources can move forward and backward freely, speeding up the transport of bridge section and returning back to sections yard. Consists of self-propelled unit and non-drive unit.
- 4 or 6 cylinders diesel engine
- 4 level reducer to drive the trailer. Mechanical gear drive system
- Hydraulic steering
- Air brake system
- Multi gears for moving forward and backward
- Non-drive unit equipped with a small engine to supply power for steering
Specialized in transport of 16m, 20m, 24m and 32m T section beam for high-speed railway. Custom design of long beam trailer is available.
SPMT for long beam
Using two modules of SPMT for long beam transportation: this way can make sure two units of SPMT can move and steer simultaneously which is the best way to protect the long beam from torsion.
With help to hydraulic lifting cylinders in the SPMT, the long beam could be elevated or lowered to pass through obstacles easily. And independent suspensions minimize turning radius accordingly.
Turntables and bolsters
Using turntables and bolsters could minimize turning radius of the long beam, also can protect the beam from distortion during steering and distribute weight on the long vessel trailer.
Advantages of self-propelled long vessel trailer
- Less equipment and labor needed
- High efficiency
- Can move forward and backward, no need turning back
- Less maintenance cost
- Less working procedures to maintain a safer condition
Loading procedures of long vessel trailer
- Clear obstacles on path and overhead
- Make sure pressure is allowed on the way when the trailer is loaded
- Flatness of path is needed
- Drive the trailer to the position under RTG
- COG of bridge section should on top of center line of the trailer
- Align all support points
- Using supporting rods and chain block to fix the bridge beam on the trailer
- Cushion wood or rubber are needed between beam and trailer
- Slow gear to start engine, slow speed with beam load, high speed with an empty load
- A safety observer should monitor the whole process of transport, should notice drive to stop the trailer if abnormity detected
- Before moving the trailer with the beam, braking air pressure must be above 6Mpa
- Braking test before entering the launching girder
- During the process of feeding beam, drive the trailer from the tail side of launching girder slowly
- Trailer’s speed is same as that of overhead crane of launching girder
- After launching girder lifted the beam section completely, the long beam trailer can backward to section yard
How to fix long beam on trailer
- Using round woods to support both sides of the beam
- Using 4 units of high tensile steel pipe to support both sides of the beam, make sure no overturn happens
- Using 4 sets of steel ropes and chain blocks to tie up the beam on both ends, to strengthen the fixture
- Please check below sketch drawing
Path requirements for beam transport
- Width of road higher than 5 meters
- Longitudinal slope less than 3.5%
- Latitudinal slope 4% to drain water
- Road bearing capacity higher than 0.5Mpa
Click steering dolly to know more info about it
Using two modules of modular trailer or steering dolly: this is the most cost-effective way to transport the long girder or long beam, but the beam should be strong enough to tow the rear trailer, and it also needs to bear turning force between two modules because they cannot move and turn simultaneously.
Application scenarios of long beam trailers: most used in elevated road construction, railroad and road bridge construction, long pipeline, vessel and steel structure transportation. For railroad maintenance, you may need a railroad crane.