Trestles are pivotal structures in marine and foundation construction—where they serve as platforms for access, material transport, and equipment stability. These raised frameworks of beams and supports are often used in challenging environments such as offshore construction sites or areas with unstable soil. While they can be temporary or permanent, trestles play an essential role in ensuring that construction processes proceed safely and efficiently—especially in projects involving deep foundations and pile driving.

What are Trestles?

Trestles are bridge-like structures typically made from wood, steel, or concrete—designed to elevate workers, equipment, and materials above ground or water. They are often used to provide stable access to areas that are otherwise difficult to reach—such as over bodies of water or swampy ground—and are commonly seen in the construction of piers, bridges, and other infrastructure projects. Trestles are versatile and can be used in a wide range of construction tasks, from transporting heavy machinery to supporting temporary equipment during critical stages of building.

While they can be used in a variety of industries, trestles are commonly associated with marine and foundation construction—particularly for projects that require temporary access or support. They are typically built to withstand high loads and environmental stresses but are often removed once the primary construction phase is completed. In some cases, however, trestles can be left in place for ongoing use or as permanent features for specific projects.

Types of Trestles in Marine and Foundation Work

There are several types of trestles that cater to the specific needs of marine and foundation construction. The design and construction of each type of trestle depend on the requirements of the job site and the intended use. Below are the most common types of trestles found in these industries…

Access Trestles

Access trestles are built to provide a safe and stable platform for workers and machinery to reach difficult-to-access areas. In marine construction, for instance, these trestles can be used to provide elevated walkways or bridges that span water bodies or muddy land. These structures are critical for offshore projects where workers need to get to platforms, ships, or barges. They are also useful in foundation work, allowing workers to safely move across unstable soil or areas with varying ground levels.

Railway Trestles

Railway trestles are used to support the transport of materials or machinery, often seen in pile driving and foundation projects. These trestles enable rail transport of heavy loads to remote or difficult-to-reach locations. In marine environments, railway trestles can be used to move materials between land and water-based locations or to facilitate material transportation to offshore sites.

Temporary Support Trestles

These trestles are specifically designed to support construction equipment, such as cranes or pile drivers, during the initial stages of a project. Temporary support trestles are commonly used in pile driving operations to elevate heavy machinery above the waterline or unstable ground. These trestles allow contractors to work more efficiently, providing the necessary stability for operations that require a solid foundation for equipment.

Permanent Trestles

In some cases, trestles may be constructed as permanent features of a project. These are typically used in long-term marine construction or foundation work, where access to certain areas needs to be maintained throughout the life of the project. For example, trestles can be used in the construction of bridges, piers, or offshore facilities—where continuous access is necessary for the maintenance of equipment or transportation of materials.

The Construction and Design of Trestles

Building a trestle requires careful planning—particularly in terms of material selection, load-bearing capacity, and the environmental conditions of the job site. Trestles must be engineered to support not only the weight of construction materials and machinery but also withstand forces like wind, water, and shifting ground. Several key design elements must be considered when constructing a trestle for marine or foundation work…

Load-Bearing Capacity

The primary function of a trestle is to bear the weight of materials, equipment, and personnel. Therefore, the design of a trestle must account for load distribution and the structural strength needed to support these loads. The weight of cranes, pile drivers, and other heavy machinery must be evenly distributed across the trestle’s beams and supports to prevent structural failure. Additionally—the trestle must be built to withstand dynamic loads, such as the movement of machinery or materials, as well as static loads like the weight of the structure itself.

Material Selection

The materials chosen for a trestle depend on the specific demands of the job site. Steel and concrete are commonly used for their strength, durability, and resistance to corrosion—especially in marine environments where saltwater exposure can accelerate the deterioration of materials. Wood is sometimes used for smaller, temporary trestles—though it likely will not provide the same longevity as steel or concrete.

In marine construction, materials need to be carefully selected to prevent rust and corrosion—with galvanization or other protective coatings often applied to steel components. Additionally—in foundation construction, where trestles are subjected to high compressive forces, reinforced concrete or steel is typically preferred.

Environmental Resilience

Trestles used in marine construction face additional challenges due to their exposure to water, wind, and salt. As a result, these structures must be designed to resist the harsh marine environment. For example, corrosion-resistant coatings on metal components and the use of concrete with waterproof additives can help extend the life of trestles exposed to saltwater. Additionally, trestles must be built to withstand the forces of tides, waves, and storms—ensuring their stability even under extreme conditions.

Height and Accessibility

Trestles must also be designed with height and accessibility in mind. They need to be tall enough to provide safe access to work sites or support the movement of heavy machinery. In marine construction, for example, the trestle must be elevated enough to allow for easy transport of materials to and from barges or ships. For foundation work, the height must accommodate the clearance needed for pile driving equipment or other construction machinery.

Applications in Marine and Foundation Construction

Trestles are widely used in marine construction and foundation drilling, where they provide critical support and access during challenging phases of the construction process…

Pile Driving

Trestles are essential in pile driving operations, where heavy machinery like pile drivers or cranes need to be elevated above water or unstable ground. These temporary structures ensure that the equipment remains stable and functional during the driving of piles into the ground. In many cases, trestles are used to support cranes that load and unload materials from barges or transport equipment across difficult terrain.

Marine Construction

In marine construction—trestles facilitate the building of piers, bridges, and other offshore infrastructure. They provide access to the site for workers and equipment, which is crucial when working over water or other challenging terrains. Trestles can also be used to support the transport of materials from land to water, ensuring that necessary resources are available for construction activities.

Foundation Drilling

For foundation drilling in soft or unstable soil conditions, trestles help support drilling rigs and machinery. These structures elevate the drilling equipment above the unstable ground, providing a stable platform for operation. In addition, trestles are used to transport drill materials and remove excavated earth from the site.

Safety Considerations

Given the often challenging environments in which trestles are used, safety is a top priority. Proper design and maintenance are essential to ensure the structural integrity of the trestle, particularly when supporting heavy equipment or working in marine environments. Safety protocols include:

• Load limits: Operators must adhere to the specified load limits to avoid overburdening the trestle, which could lead to collapse or failure.
• Regular inspections: Trestles should be inspected regularly to ensure that they are stable and safe for use. This is especially important in marine environments, where corrosion can weaken the structure over time.
• Protective barriers: Trestles should be equipped with safety barriers or guardrails to prevent workers from falling or being exposed to hazards like moving machinery.

Case Studies: Successful Applications of Trestles in Marine and Foundation Projects

Below are a few examples of successful trestle applications in different sectors of construction…

Case Study: Offshore Platform Access for Oil and Gas Construction

In a large offshore oil and gas construction project, trestles played a crucial role in providing access to the worksite for both workers and heavy machinery. Due to the challenging conditions of working in deep water, traditional access methods were not feasible. The construction team designed a series of steel trestles, elevated above the water’s surface, which served as safe walkways for personnel and stable platforms for material transport.

The trestles were constructed with corrosion-resistant steel to withstand the harsh marine environment, and their modular design allowed for easy adjustments to accommodate the fluctuating water levels due to tides. These trestles enabled uninterrupted work on the offshore platform while keeping workers safe and minimizing downtime caused by weather conditions.

Case Study: Pile Driving in Soft Soil for Bridge Construction

A project in a coastal area required extensive pile driving to build a new bridge. The worksite was characterized by soft, marshy soil—which made it difficult to support the large cranes and pile drivers needed for the operation. The project team used temporary wooden trestles to elevate the pile-driving equipment, providing the necessary stability for the machinery to perform effectively.

The wooden trestles were designed with reinforced beams to handle the weight of the heavy pile-driving rigs. By elevating the equipment above the unstable ground, the team was able to safely and efficiently complete the pile-driving process—which would have otherwise been delayed due to the site’s difficult conditions. The trestles were removed once the bridge foundation was complete, demonstrating the temporary yet critical role of trestles in construction.

Case Study: Marine Piers and Wharf Construction

A marine contractor working on the construction of a new commercial wharf needed to ensure that the project could be completed efficiently while providing continuous access to the site. The contractor employed steel trestles to support the transportation of materials from shore to barges, which then ferried them to the construction site. These trestles were placed along the coastline, with sections extending out into the water to allow cranes and trucks to load and unload heavy materials.

The trestles were designed to handle the weight of large cargo containers and equipment, and their strategic placement allowed for a steady workflow throughout the project. Additionally, the trestles provided workers with a safe route to navigate the waterlogged terrain—reducing the risk of accidents. As the project progressed, the trestles were gradually incorporated into the wharf’s permanent infrastructure—transitioning from a temporary to a semi-permanent role.

Case Study: High-Altitude Foundation Drilling

In a remote mountainous region, a foundation drilling project was required for a series of new buildings. The site was at a high altitude, and the steep terrain made it difficult for standard machinery to reach the drilling locations. The construction team designed custom-built trestles that elevated the drilling rigs above the rugged terrain, providing safe and stable access to the drilling sites.

These trestles were built with steel beams to ensure the support of heavy drilling equipment. The team also incorporated additional safety features such as guardrails and secure walkways for workers. By using trestles to provide the necessary height and stability, the project was completed on schedule despite the challenging landscape. The temporary trestles were dismantled after the drilling was completed and the foundations were poured, leaving the site ready for further construction.