Key takeaways
Pipeline infrastructure ensures a secure foundation for heavy equipment and vehicles during a pipeline project; it’s a critical aspect of safety, efficiency, and project success. Timber mats are pipelines indispensable allies keeping pipeline equipment level, spreading its weight and protecting the ground beside an open trench.
- Lowering-in puts the heaviest machines beside the ditch: pipe 36 inches and larger needs at least 3 sideboom tractors working in unison, per the INGAA Foundation construction primer.
- OSHA requires a protective system in excavations 5 feet or deeper, and soil that is submerged or freely seeping water is automatically Type C, the least stable class.
- Wet ground multiplies damage: a load of 10 tons per axle on wet soil can compact it to 2 feet or more, according to University of Minnesota Extension.
- Select Mat timber mats are 8 inches of dense hardwood in 4’ x 16’ and 4’ x 18’ sizes, built for heavy tracked equipment. Laminated mats are not built for tracked cranes or bulldozers.
Why pipeline right-of-way work needs a stable working platform
Pipeline right-of-way work needs a stable platform because the heaviest machines on the job operate beside an open trench. According to PHMSA’s overview of construction phases, welded pipe is lowered into the trench with sidebooms and track hoes, and transmission lines in rural areas must be buried at least 30 inches deep.
The INGAA Foundation’s typical layout for 36-inch pipe in Type B soil totals 65 feet of working side, including a 2-foot OSHA trench offset and two excavator and sideboom lanes of 14 to 18 feet each. Lowering-in also creates some of the largest combined stresses a pipeline will see, per the same primer. If one sideboom settles into soft ground, the load shifts to the machines beside it.
A pipeline right-of-way is defined as the strip of land used to build, operate and maintain a pipeline. Ground bearing pressure refers to a machine’s weight divided by the ground area supporting it. Mats lower it by enlarging that area.
Timber mats explained
Timber mats, also known as Dragline Mats, Digging Mats, Mud Mats, Pipeline Mats, or Crane Mats, are not your run-of-the-mill construction material. They are the workhorses of the industry, trusted for their durability, versatility, and unmatched stability. A timber mat is a heavy-duty access mat made from dense hardwood, 8 inches thick, that creates a stable, level working surface under equipment. Unlike access mats such as 3-ply laminated or cross laminated timber (CLT) mats, timber mats offer a superior strength-to-weight ratio, making them the preferred choice in demanding environments where steel tracked equipment reigns supreme.
At their core, timber mats are sturdy platforms crafted from high-quality timber, meticulously engineered to withstand the rigors of heavy-duty construction activities. Their construction typically involves interlocking wooden planks, creating a robust surface capable of supporting heavy loads and providing traction in challenging terrain.
On construction sites, where the ground is often uneven and unpredictable, timber mats provide a sense of stability that’s essential for safe and efficient operations. By distributing the weight of heavy machinery and equipment, timber mats minimize ground disturbance, reducing the risk of soil erosion and environmental damage.
Moreover, timber mats serve as invaluable tools for access and mobility, enabling construction crews to navigate challenging terrain with ease. Whether it’s providing a stable pathway for vehicles or creating temporary bridges over waterways, timber mats facilitate seamless movement on the job site, enhancing productivity and minimizing downtime.
How 8-inch timber mats distribute load from sidebooms and excavators
When it comes to pipeline projects, where steel tracked equipment is heavily utilized, standard mats might not meet the mark. With measurements commonly available in 8”x4’x16’ or 8”x4’x18’, timber mats provide a sturdy foundation that can withstand the weight and force exerted by heavy excavators, cranes, and other machinery. An 8-inch timber mat spreads a tracked machine’s weight across a larger footprint than its tracks alone.
According to the INGAA Foundation primer, “The timber mats act much like snowshoes, spreading the weight of the construction equipment over a broad area making it possible to operate the heavy equipment on the unstable soils.”
Thickness makes the snowshoe work. A stiff 8-inch mat resists bending, so a track load spreads along its 16- or 18-foot length instead of punching through at the track edges.
Compaction also outlasts the job: University of Minnesota Extension reports it can cut crop yields by as much as 60 percent, which matters when restoring farmland.OSHA already treats mats as ground support: under 29 CFR 1926.1402, supporting materials are defined as “blocking, mats, cribbing, marsh buggies (in marshes/wetlands), or similar supporting materials or devices.” Sideboom cranes are exempt from that ground-conditions section under 29 CFR 1926.1440(a), so their ground support falls to the contractor’s own plan.
Preventing rutting and tip-over on soft and saturated soils
By providing a solid foundation for equipment and vehicles, timber mats serve as the frontline defense against accidents, injuries, and damage to property. Whether it’s a crane hoisting a heavy load or an excavator maneuvering through challenging terrain, timber mats offer a secure footing that minimizes the risk of rutting, slippage, tipping, or rollovers. This not only safeguards the well-being of personnel but also protects valuable assets from harm, ensuring that every operation unfolds with utmost care and caution.
Timber mats prevent rutting by keeping tracks above the weak surface layer where ruts start. A rut under one track tilts the machine, and a tilted sideboom carrying pipe off its side can tip.
Federal wetland rules name mats directly. Per FERC’s Wetland and Waterbody Construction and Mitigation Procedures (May 2013 version), “If standing water or saturated soils are present, or if construction equipment causes ruts or mixing of the topsoil and subsoil in wetlands, use low-ground-weight construction equipment, or operate normal equipment on timber riprap, prefabricated equipment mats, or terra mats.” The same procedures keep extra work areas at least 50 feet from wetland boundaries.
Mats help only when the surface stays continuous. See our guides to board road gaps and construction mat safety.
Trench-edge safety under OSHA 1926 Subpart P
Mats support trench-edge safety by keeping equipment level and stable, but they never replace a protective system. OSHA’s trenching page states that cave-ins pose the greatest risk to workers’ lives.
29 CFR 1926.652 requires a protective system for excavations 5 feet (1.52 m) or deeper unless they are in stable rock, and its default sloping option is no steeper than 1.5 horizontal to 1 vertical (34 degrees). Under Appendix A, no soil is Type A if it is subject to vibration from heavy traffic.
Per 29 CFR 1926.651(j)(2), “Protection shall be provided by placing and keeping such materials or equipment at least 2 feet (.61 m) from the edge of excavations.” On Type C ground, the competent person may set a larger setback.
The Department of Labor reported 22 trenching and excavation deaths in the first half of 2022, more than the 15 in all of 2021, and noted that a cubic yard of soil can weigh as much as 3,000 pounds. The Bureau of Labor Statistics counted 1,032 fatalities among construction and extraction workers in 2024, out of 5,070 fatal work injuries overall.
When timber beats laminated or composite mats on pipeline jobs
Timber beats laminated or composite mats when heavy tracked equipment works soft ground for extended periods.
Mat type | Build and size | Heavy tracked equipment | Best pipeline use | Watch for |
|---|---|---|---|---|
Dense hardwood, 4’ x 16’ x 8” or 4’ x 18’ x 8” | Yes: sidebooms, excavators | Ditch-side working lanes, lowering-in, temporary roads | Heavier to haul; wood can hold contaminants | |
3 layers of hardwood boards, 8’ x 14’ or 8’ x 16’ | No: not for tracked cranes or bulldozers | Access roads for rubber-tired trucks | 18-20 (8×14) or 15-17 (8×16) per truck | |
HDPE, 8’ x 14’ x 4”, 1,000 lbs, 600 psi | Yes, tracked or rubber-tired | Sensitive or contaminated areas, uneven terrain | Flexes under point loads; check load limits | |
Hardwood with steel rods, 4’ wide, 12’ to 40’ long, 12” thick | Yes: crawler cranes, drilling rigs | Tie-in crane pads, spanning trenches and waterways | Thickest and largest category |
Frequently asked questions
These answers cover the questions pipeline crews ask most about timber mats on right-of-way work.
What size are timber mats for pipeline work?
Timber mats come in two sizes: 4 by 16 feet and 4 by 18 feet, both 8 inches thick and made from dense hardwood. They are built for heavy tracked equipment such as sidebooms and excavators, and are stronger than laminated or CLT mats. For spanning trenches or supporting crawler cranes, 12-inch crane mats are the next step up.
Can laminated mats support sideboom tractors?
Laminated mats should not be used under sideboom tractors or other heavy tracked machines. Laminated mats are three layers of hardwood boards, nailed or bolted, built as medium-duty mats for rubber-tired equipment, not cranes or bulldozers. On a pipeline spread they suit access roads for trucks, while timber mats belong under sidebooms along the ditch.
Do timber mats replace trench shoring or shielding?
Timber mats do not replace shoring, shielding or sloping under OSHA rules. Under 29 CFR 1926.652, any excavation 5 feet or deeper needs a protective system unless it is entirely in stable rock. Mats keep equipment level and spread its load near the edge, but only sloping, shoring or shielding protects workers inside the trench.
How far from a trench edge should equipment and mats stay?
OSHA sets a minimum of 2 feet (0.61 meters) from the excavation edge for materials and equipment that could fall or roll into it, unless retaining devices are used. Treat that as a minimum. Saturated or seeping soil is Type C, the least stable class, so plan mat runs with the loaded edge set well back.
Why do saturated soils cause more rutting and tip-over risk?
Saturated soils lose strength, so tracks sink until they find firmer ground. Uneven sinking tilts the machine, and a sideboom holding pipe off one side is sensitive to tilt. Mats spread the load so tracks stay on a level surface above the weak layer.
Are timber mats allowed in wetlands on FERC-regulated pipelines?
Yes, FERC’s wetland procedures name timber riprap and prefabricated equipment mats as accepted ways to support equipment. When standing water or saturated soils are present, or equipment causes ruts, crews must use low-ground-weight equipment or work from mats. The procedures also require removing all equipment-support material when construction ends. Check Army Corps and state permit conditions too.
When should a pipeline contractor choose composite mats instead of timber?
Composite mats make sense where contamination control, cleaning between sites or uneven terrain matter most. Select Mat composite mats are HDPE, 8 by 14 feet, 4 inches thick, rated at 600 psi, and non-absorbent. Timber is the better fit for sustained heavy tracked loads beside an open ditch, where stiffness spreads weight more evenly.
Does OSHA’s crane ground-conditions rule apply to sidebooms?
No, OSHA’s ground-conditions section, 29 CFR 1926.1402, does not apply to sideboom cranes under 29 CFR 1926.1440(a). It still applies to other cranes on the job, such as crawler cranes at tie-ins, and lists mats as supporting materials. For sidebooms, ground support depends on the contractor’s own lift and site plans, which is where matting belongs.
Planning a pipeline spread on soft or saturated ground? Select Mat supplies timber, crane, laminated and composite mats with installation, hauling and load capacity planning across the continental US. Request pricing through our Quick Quote form or call (800) 735-3286. Select Mat has supplied access mats since 2017 and is rated 5 out of 5 across 1,754 client reviews.
