Structural Steel Hauling Services
Structural steel presents a unique set of transportation challenges that separate it from most heavy equipment moves. A large bridge plate girder can be 8 feet deep, 150 feet long, and weigh 80,000 to 120,000 pounds — simultaneously overheight, overwidth, overlength, and overweight. A bundle of wide-flange beams can be legal in width and height but extend well beyond the 53-foot legal trailer length, triggering overlength permits and rear pilot car requirements in virtually every state.
R&RM LLC, based in Cumming, Georgia, has been handling oversize load transport across all 48 continental states since 2011. We work with steel fabricators, bridge contractors, general contractors, and erection crews to move structural steel — from individual wide-flange columns to complete bridge superstructure packages — from the fabrication shop to the job site on time and in compliance with state permit requirements.
Types of Structural Steel We Transport
Wide-Flange Beams (W-Sections)
Wide-flange beams are the most common structural steel shape in North American construction — the "I-beam" profile used in building frames, bridges, industrial structures, and infrastructure projects. W-sections are designated by their nominal depth and weight per foot: a W36x150 is approximately 36 inches deep and weighs 150 pounds per linear foot.
- Small W-sections (W8–W18): Typically 20–40 feet long, 200–2,000 lbs per piece — multiple pieces bundled on flatbed or step deck trailers
- Medium W-sections (W21–W30): Commonly 30–60 feet long, 1,500–10,000 lbs per piece — extendable flatbeds for longer lengths, overwidth permits for wide bundles
- Large W-sections (W33–W44): Often 40–80 feet long, 5,000–40,000 lbs per piece — overlength permits required, sometimes overheight when standing on their flanges
- Heavy W-sections (W14x500–W14x873 columns): Short but extremely heavy. A W14x873 column weighs 873 lbs per foot — a 20-foot column piece is 17,460 lbs. These move on heavy-duty flatbeds with overweight permits when bundled.
Bridge Plate Girders
Bridge plate girders are custom-fabricated welded steel assemblies used in highway bridges, railroad bridges, and pedestrian bridges. Unlike standard W-sections, plate girders are built to project-specific dimensions and are often the most logistically demanding structural steel loads a carrier will handle.
- Haunched girders: Variable-depth plate girders that are deeper at the pier supports than at midspan. The deep haunch section can be 8 to 12 feet tall, requiring overheight permits even when loaded flat and creating challenges for bridge clearance routing.
- Curved girders: Horizontally curved bridge girders follow the radius of a curved roadway alignment. Their curved plan shape requires special attention to lateral stability during transport and often mandates specific trailer configurations and tie-down patterns.
- Straight constant-depth girders: The most common bridge girder type. Depths of 4 to 7 feet are typical for highway overpass spans; longer river crossing girders can be 8 to 12 feet deep. Lengths of 80 to 200 feet are not uncommon for major bridge projects.
- Through-girder assemblies: Partial sub-assemblies of bridge girders connected with cross-frames or diaphragms at the fabrication shop, shipped as an assembly to reduce field connection work.
Steel Box Girders
Steel box girders — closed rectangular cross-sections — are used in long-span bridges, cable-stayed bridges, and elevated transit structures. Box girder sections can be extraordinarily wide: a 14-foot-wide box girder section requires superload-level width permits in most states. They are typically transported on multi-axle specialized trailers with hydraulic suspension to maintain level loading.
Structural Steel Columns and Trusses
Heavy industrial columns, lattice towers, and pre-assembled truss segments are moved on flatbed, step deck, and RGN trailers depending on their profile and length. Tall columns may require standing upright in specialized A-frame transport fixtures, which can push the overall height above standard oversize thresholds. Pre-assembled truss sections for roof structures and industrial buildings are often wider than a standard lane and require overwidth permits with pilot car escorts.
Steel Decking, Grating, and Plate
Steel floor decking, checker plate, and structural plate are typically shipped flat on standard flatbeds, but wide loads and very heavy plate bundles can require overweight or overwidth permits. Very wide plate materials — 12 to 14 feet wide sheets of structural plate — are common in tank and vessel fabrication and require overwidth permits when transported as a unit or in bundles that exceed the 8-foot-6-inch legal width.
Trailer Types for Structural Steel Hauling
Standard Flatbed Trailers
A standard 48-foot or 53-foot flatbed trailer handles most structural steel that fits within legal dimensions — short-to-medium W-sections bundled to standard width and height, structural plate, and fabricated steel assemblies within legal limits. The high deck of a flatbed can reduce the effective headroom beneath overhead utilities, so loading height for tall bundles must be confirmed against the route's clearance constraints.
Extendable Flatbed Trailers
Extendable flatbeds stretch the trailer bed from a standard 48 or 53 feet to 80 feet or more. They are the primary tool for hauling long bridge girders, long W-section beams, and other structural steel that exceeds standard legal trailer length. An overlength permit is required in every state for loads extending beyond 53 feet, and in most cases a rear pilot car is mandatory once the load reaches 70 or 75 feet in overall combination length.
Multi-Axle Lowboy and RGN Trailers
RGN (removable gooseneck) trailers and multi-axle lowboy trailers are used for very heavy structural steel that exceeds flatbed axle ratings. A lowboy or RGN also provides a lower deck height than a flatbed, which is essential for tall bridge girder sections that would be overheight on a standard flat deck. Multi-axle configurations — 4, 5, 6, or more axle lines — distribute weight across more tires and allow heavier loads to be moved within per-axle weight limits.
Specialized Beam Trailers
For the longest structural members — bridge girders over 150 feet in length — specialized beam trailers with a steerable rear dolly are used. The front of the beam is supported by the tractor's fifth wheel pin via a bolster, and the rear is supported by the trailing dolly. The rear dolly is controlled separately to navigate curves and is coordinated by a rear pilot car crew. These moves require advanced route surveys, utility clearance confirmation, and in some corridors, special access agreements from state DOTs.
Oversize Permit Requirements for Structural Steel
Structural steel transport triggers different permit categories depending on the load's actual dimensions:
- Overlength: Any trailer combination over 53 feet requires an overlength permit. Loads extending 75 feet or more in overall length require a rear pilot car in most states; loads over 100 feet require a front escort in many states as well.
- Overwidth: A wide bundle of W-sections, a wide girder flange, or a wide plate assembly that exceeds 8 feet 6 inches requires overwidth permits. Most states allow up to 14 or 16 feet wide on standard oversize permits; widths above that enter superload territory.
- Overheight: A deep plate girder standing on a flatbed deck can exceed 13 feet 6 inches total height, triggering overheight permits and requiring advance bridge clearance analysis along the route.
- Overweight: A very long, heavy plate girder may weigh 100,000 pounds or more. Combined with the tractor and trailer, the gross vehicle weight can exceed 200,000 pounds, requiring a multi-axle trailer configuration and overweight permits from each state on the route.
Our permit services team handles the full permit application process — determining which permits are required based on your steel's actual dimensions, submitting applications to each state, and confirming that the routing, travel windows, and escort requirements are met before the load departs the fabrication shop.
Industries That Ship Structural Steel
- Bridge Construction: State DOT bridge projects, county bridge replacements, railroad bridge rehabilitation, and pedestrian bridge installation. Bridge girder shipments are among the most technically demanding structural steel moves in the industry.
- Commercial Construction: High-rise building frames, parking structures, industrial buildings, and retail centers require large quantities of wide-flange sections delivered from steel service centers or fabricators to the construction site.
- Industrial Fabrication: Structural steel for process plant buildings, tank farms, petrochemical plant structural systems, and power plant structural frames delivered from fabrication shops across the country.
- Energy Infrastructure: Transmission tower sections, substation structural steel, wind turbine tower base rings, and solar racking system structural members.
- Mining and Resources: Conveyor support structures, crusher building frames, mill building superstructure steel, and headframe structural members for mining operations.
- Port and Marine: Dock fender systems, pier structural steel, overhead crane runway girders, and marine loading structure steel.
Loading and Blocking Structural Steel for Transport
Structural steel — particularly individual girder pieces — must be loaded and blocked carefully to prevent damage to coatings, welds, and connection plate details. Bridge girders are typically shipped on timber or rubber dunnage at specific brace points to avoid deformation. Horizontal curved girders must be blocked to maintain their curve and prevent lateral buckling during transit. Individual column sections with shop-applied primer or galvanizing must be protected from abrasion by blocking and banding materials.
For loads where the steel fabricator specifies blocking requirements — as is common on bridge projects with engineer-of-record approval requirements — we work with the fabricator's transport engineer to ensure the trailer configuration and tie-down plan meet project specifications. For oversize structural steel moves, we confirm load blocking, banding, and tie-down patterns before departure and document the configuration for the permit records.
Get a Quote for Structural Steel Transport
To quote a structural steel move, provide the member dimensions (length, depth or height, flange width), approximate weight per piece and total shipment weight, number of pieces or bundles, origin fabrication shop or service center location, and delivery job site address. For bridge girder moves, a copy of the erection plan or girder schedule is helpful but not required for an initial estimate.
Call R&RM LLC at (404) 987-6225 or submit a detailed quote request online. We will identify the trailer configuration, permit requirements, and routing plan that get your steel delivered safely and on schedule.
Related Equipment & Services
- Pressure Vessels & Process Tanks — large industrial vessels and process equipment
- Industrial Boilers & Heat Exchangers — process vessels and heat transfer equipment
- Cranes — crawler cranes and all-terrain cranes used in steel erection
- Oversize Load Transport — permit, routing, and escort services for oversize loads
- Permit Services — oversize and superload permit applications across all 48 states