Trailer floor systems are much more complex than simply a set of floorboards secured to crossmembers that run between bottom rails.
Designed to effectively distribute loads throughout the vehicle’s structure, the floorboards and crossmembers share the load and allow weight to be transferred to the bottom rails, walls and eventually to the upper coupler and running gear. At that point the load is transferred to the tractor and trailer suspensions, and eventually to the ground.
As one of the critical elements of a floor system, floorboards made of appropriate materials for the loads being hauled help minimize stresses on components, eliminate failures and lead to longer trailer service life. “There are different types of flooring,” says Gopal Padmanabhan, product development engineer at Havco Wood Products, “including hardwoods such as laminated oak and maple, composite materials and aluminum. Oak is the most common, fleets hauling heavy and water sensitive loads use composite, and aluminum is used when floors need to be washed.
“There are numerous factors that fleet managers need to consider when specifying trailers floors,” Padmanabhan continues. “Those include load rating, decay resistance of the wood, nailing requirements, wood used, type of loads hauled, expected life, maintenance to perform, lifetime cost and trade-in value.”
Most fleets prefer oak for its long history of use in trailer flooring, Padmanabhan notes. “Many, especially large operations, know from years of experience that oak is much more resistant to decay than other common hardwoods,” he says. “It is important for fleet managers to spec flooring by wood species and brand. That maintains a certain standard because the flooring type and wood used affect long term performance.”
Padmanabhan goes on to say that it helps to work with flooring suppliers when specifying trailers because they can provide specific information about their products. “While flooring is one component of a trailer floor system,” he advises, “the trailer OEM can also provide detailed information about crossmembers, connections, load ratings, floor testing and its relevance to the transport application. When fleet managers gather all this information, it puts them in the best position to spec the most cost effective floor systems.”
In addition to oak hardwood, Havco offers composite flooring, which it says offers high strength, fatigue resistance and improved waterproofing and weight savings. Havco composite flooring is based on conventional laminated oak flooring. Each floorboard is reinforced at the underside by adhesively bonding a continuous panel of glass-fiber reinforced epoxy, which, according to the manufacturer, is several times stronger and stiffer than wood and therefore allows for the use of a thinner layer of wood to provide weight savings.
Havco composite flooring is available in the several thicknesses. Typically, 1-1/16 in. flooring is used to replace 1-5/16-in. conventional laminated hardwood flooring and can save about 228 lbs. in a trailer while 1-1/8-in. is used to replace 1-3/8-in. hardwood. A 1-3/16 composite floor, designed for 20,000 lbs. and higher load capacities, can save about 323 lbs. compared to 1-1/2-in. conventional laminated oak flooring. In addition, the company points out that its 1-5/16-in. and 1-3/8-in. composite flooring can be used with fewer crossmembers, and there can also be additional weight savings from the exclusion of moisture.
Rockland Flooring offers red and white oak and hard maple floors for trailers. The company also offers composite flooring made of traditional laminated wood and a specially formulated substrate bonded to the wood called Davilon. According to the company, the Davilon composite floor is stronger and more durable than traditional flooring. In addition, when the wood naturally contracts and expands, the Davilon will move with it and not against it. The substrate, which is manufactured from 100 percent recycled polymers, is environmentally friendly.
Overseas Hardwoods offers its Road Load Tested (RLT) flooring for flatbed, drop deck and step deck trailer floors. RLT Flooring eliminates all interior board ends (usually more than 100 per trailer floor) that the manufacturer says are subject to rot, wear and damage from forklifts. The result, the company notes is longer trailer floor life and lower maintenance costs.
Spec’ing trailer for productivity includes choosing the right floor for each application. While part of an overall trailer floor system, flooring is one of the most important factors in determining durability.
Protecting Trailer Floors
Once a trailer floor coating has been breached, water can migrate into the trailer, resulting in cargo damage, high repair costs and reduced service life. To help eliminate this possibility, Great Dane Trailers is now using PuR from Prolam, a hot-melt polyurethane reactive (PuR) coating that resists moisture intrusion from underneath the trailer more effectively than standard water-based paint coatings.
Designed to provide a superior moisture barrier, increase durability and reduce floor maintenance costs, Prolam PuR provides protection for wood trailer floors especially in climates with extreme weather conditions. Water-based paint systems used to protect the underside of trailer floors can break down when subjected to intense water spray and road debris, the OEM points out. Specific areas, like trailer wheel locations, are more prone to degradation. In sandblast tests, PuR was 11 times more abrasion-resistant than water-based coating. In several other standardized tests as well, PuR outperformed water-based trailer coatings.
Once water-based paint breaks down, the company notes, the wood absorbs moisture, causing warping, swelling and deterioration of glue bonds. PuR, it says, has superior moisture resistance because it has a thickness of .010-inches compared to .0035 inches for water-based coating. Its viscosity allows it to adhere perfectly to wood laminate, creating a solid bond and providing a single uniform sheet barrier against moisture under laminated hardwood floors. PuR can even “bridge” wood defects, knots and critical areas like butt-end joints.
DOORS
One of the choices fleet managers make when specifying trailers involves doors. While traditional swing type rear trailer doors offer the widest opening for maximum loading, for fleets that make multiple deliveries and pickups, roll up or overhead rear doors may be a better solution.
TODCO offers overhead trailer doors for dry freight and refrigerated applications, including its new PolarTek overhead refrigerated door. PolarTek is constructed of extruded hollow-core polycomposite panels. The panels are foamed in place with moisture resistant, thermal efficient polyurethane foam, whose thousands of tiny air pockets prevent BTU loss while adding strength and rigidity. In addition, the design of the PolarTek door offers a smooth finish that makes graphic applications more effective and painting optional.
TODCO also offers its ArmorPlate Overhead Truck Door for dry freight trailers. ArmorPlate overhead doors feature steel skins bonded to a solid high-density polyethylene composite core. The steel skins are designed with the durability to stand up to heavy freight, frequent stops and over-the-road weather conditions. In addition, the polycomposite core is impervious to moisture, adding protection for cargo while providing extra structural strength. The doors can be painted or incorporate pre-painted coil to match fleet color specifications.
Whiting Door Manufacturing Corp. is offering composite doors made from materials that will not deteriorate due to moisture, which has been a leading cause of trailer door deterioration and reduced service life. Whiting composite door models include:
• PremiumPlate –– A composite plate roll-up door constructed from 1/2-in. polyethylene core panels and high tensile pre-painted steel facings with a baked-on polyester finish. The PremiumPlate door also features rigid tongue-and-groove panel joints, a full width rigid extruded aluminum seal retainer and E-coated hardware and hinges.
• Eurocel — A roll-up design with a polymer-blend panel core edged with a permanently bonded anodized aluminum extrusion that forms an integral panel joint to eliminate hinges and fasteners. Also standard on the Eurocel door are a full width aluminum bottom U-channel for strength, and unique top closure brackets that require only a single set of horizontal track.
• Hinged Truss II — A roll-up hollow core extruded aluminum alloy double wall panel design that is ribbed for strength. The door’s improved PVC panel joints have two seals and a sloping design to prevent moisture intrusion while also standard is a stronger, full width extruded aluminum bottom U-channel.
• Innovator II — A significantly lighter swing door with a high impact polypropylene honeycomb core featuring a unique three-orientation cell structure that has more uniform properties and more stable tubular cells. Facings for the Innovator II include steel, stainless steel, hot dipped galvanized steel and pre-painted and mill finish aluminum.
• Plate-Lok — A swing door made from a .512-in. high-density polyethylene composite core and steel skins.
