PLAN YOUR PROJECT

This design guide is designed to help teach you best practices and help make sure we get what is needed to plan your project. It also helps ensure a quick and accurate quote for your Custom Bridge or Boardwalk.  

BRIDGE DESIGN GUIDEBOARDWALK DESIGN GUIDE

Bridge Design GUIDE

We offer Turnkey Custom Bridges and Bridge Kits to fit any site. Built to the Wisconsin DNR Trail bridge Specification 

BRIDGE FOOTINGS

Custom Bridges prefers to use our proprietary Footing System to provide the lowest cost, most environmentally friendly solution for your bridge.

Sill Footings sit directly on the ground. Riser footings elevate the bridge to provide waterway clearance (typically 5′ minimum)

Our Bridges are also compatible with Concrete Abutments 

 

LENGTH

When using our patented modular Footing System, the bridge span should be measured as depicted in the image below. The size of the footings depends on the soil conditions and will typically add 5-6 feet to the overall bridge length.  

If using a Concrete Abutment, please provide the overall length from the outside edges of the footings as shown.  

 

WIDTH

The width of your bridge should be selected to best suit the application.  

The Big Pete Footing System can be customized to support 2’ width increments starting at 4’ wide.

DESIGN SPEC

Trail bridges are built to the Trail bridge specification, which provides the best balance of loads to provide strength without over designing the structure

Bridges can also be built to the AASHTO Pedestrian Specification. This typically means the bridge sees daily traffic of 10,000 lbs vehicles.

BRIDGE STYLE

Custom Bridges offers two bridge styles, Flat and Arched.  

Each arched bridge is Custom Fabricated to ensure it meets Slope requirements. This design provides additional strength and style and can bridge longer spans than flat bridges.  

For spans greater than 110’, it is possible to chain together multiple bridges with additional footings.  

RISERS AND APPROACHES

Some bridges require additional elevation. The Big Pete Footing System can be equipped with riser legs to help lift the bridge and approaches to get to the bridge elevation.  

Approaches are customized to account for terrain changes and slope/grade requirements.  It’s possible to have an approach on end and not on the other depending on the site conditions.  

RAILING STYLE

Below we show our most common railing designs. Pedestrian Railings meet ADA requirements. We are always up to customizing the railing to suit your design. 

 

Curb railing is regularly used on Golf Courses and remote trails where a full railing is not needed.  Available in 2×6 or 2×8 or customized to your required height.  

Horizontal Pedestrian Railings come in 42” and 54” heights and feature posts around 4’ on center.  

Vertical Pedestrian railings come in 42 and 54” heights and a vertical spindle design. Crossbucks can be added as an option.  

Horizontal Trail Railings are typically used on Snowmobile bridges and other trail bridges that need a railing, but do not need ADA Compliant spacing.  

Skirts are added to cover the outer face of the I-Beams to give the appearance of an all-wood bridge. Skirts can be added to any railing design.  

DECK OPTIONS

The standard deck on our bridges are 2x10s bolted to the top I-Beam flange.  

In some situations, a second deck is desired as a wear deck or for aesthetic reasons. 

For bridges with higher load ratings or built to AASHTO Ped Spec, a 2×12 structural deck may be required. 

Composite or Rough-Cut decking can be quoted upon request.  

BRIDGE INSTALLATION

During the scoping and design stages we need some basic information about the site. As part of the quoting process, we will gather more information to help us chose the best equipment and any material needed for site restoration after the project is installed. We are happy to work with general contractors to create an accurate scope and quote for your project.  

If your order a kit, we will provide detailed instructions along with the kit and offer pre-construction support to help educate the installers and clarify any questions related the instructions.  

BOARDWALK DESIGN GUIDE

Our boardwalk system includes all of components needed to quickly design and install the boardwalk of your dreams.  Our experienced team and provide a turnkey boardwalk including design, engineering, and installation.  

All our boardwalks can be sold as a kit to be installed by the customer. Detailed instructions are provided with any kit.

Built to International Building Code standards, Custom Boardwalks can provide long lasting access to wetlands and can get you over wet areas on your property. 

BOARDWALK COMPONENTS

A typical boardwalk consists of sets of footing pans and bracket that are assembled to boardwalk panels and then decked. The Swamp Pans are used in wet conditions and the standard pans on more solid soil. A variety of brackets are available to allow the boardwalk to follow the path of your choosing.

The metal components are compatible with 4×4, 4×6, or 6×6 posts.

 

BOARDWALK DESIGN FEATURES

When the pans, brackets, and panels are combined, they fall into some typical boardwalk features. These features can be used to help plan your boardwalk

Start – The first panel requires 4 pans, 4 brackets, and a panel.

Straight Extension – Additional straight sections consist of 2 pans, 2 Universal Turn brackets, and 1 panel. The universal turn brackets allow for a very slight turn without the addition of a turn panel

Turn  – Typically built on site, the turn panel allows you to create sweeping turns to follow a shoreline or avoid obstacles in the boardwalk path. Each turn panel adds 1 Pan, 1 U-turn Bracket, and lumber to build the panel on site.

Platform – Platforms are made of multiple panels to provide additional area on a boardwalk for a lookout or a fishing pier. Platforms can be assembled without other boardwalk panels to create a free-standing deck. Inside Corner brackets provide support to the center of the platform.

 

BOARDWALK DIMENSIONS

hen configuring your boardwalk some basic dimensions will be needed to provide a quick and accurate quote.

Boardwalk Width – Usable width between the railings is typically between 4 and 12 feet.

Boardwalk Length – The total linear feet of the Boardwalk will allow us to provide a quick estimate

Number of Turns – Each turn adds additional brackets, so counting your total turns provides the last item needed for a quick estimate.

Additional Features – Please note the number of platforms or additional features desired.

 

BOARDWALK RAILING & DECKING

Boardwalks less than 2′ above ground typically get no railing or a curb railing. Pedestrian Railings meet ADA requirements. We are always up to customizing the railing to suit your design. 

 

Curb railing is the most common boardwalk railing. It provides a bump curb without blocking any of the beautiful views from your boardwalk. 

Horizontal Pedestrian Railings come in 42” and 54” heights and feature posts at 4’ on center.  

Vertical Pedestrian railings come in 42 and 54” heights and a vertical spindle design. Crossbucks can be added as an option.  

If you’d like a custom railing or custom height, just let us know in the project form and we will be happy to work on a custom railing design.

 

Boardwalks are typically decked with 5/4 x 6 Brown Stained Treated #1 Souther Yellow Pine. A 2×6 or 2×10 Deck is also available

 

PEDESTRIAN BOARDWALK

Typical Pedestrian Boardwalks are 4’ or 6’ wide, expecting only foot and bike traffic.  Designed per IBC guidelines to support a 60 psf Pedestrian load in combination with snow and other loads per the standards. 

Swamp pans are used in wetland conditions and standard on more solid ground. The 11 gauge Hot dipped galvanized pans and brackets are connected with galvanized lag screws.  

2×6 Brown-stained treated frame and 5/4 x 6 Decking provide long lasting durability. The backets and pans can be customized to support 4×4, 4×6, and 6×6 posts See: Lumber Technical Information.  

These boardwalks are easy to assemble with a crew of 3 and can be ordered as kits and assembled by the customer. See Boardwalk Installation. 

RECREATIONAL VEHICLE BOARDWALK

Recreational Boardwalks are designed to carry a 4,000 lbs. vehicle load or a 60 psf pedestrian load per IBC Standards. This is sufficient for most ATV, UTV, and Golf Cart Traffic. These bridges are typically 6 or 12 feet wide and feature panels, brackets and fasteners that provide the additional support needed for the vehicle load. 

Swamp pans are used in wetland conditions and standard on more solid ground. The 11 gauge Hot dipped galvanized pans and brackets are connected with through bolts to support the load.   

2×8 Structural, Brown-stained treated frame and 5/4 x 6 or 2×10 Decking provide long lasting durability. The backets and pans can be customized to support 4×4, 4×6, and 6×6 posts   

These boardwalks are easy to assemble with a crew of 3 and can be ordered as kits and assembled by the customer. See Boardwalk Installation.  

HEAVY DUTY BOARDWALK

Heavy duty boardwalks support loads up to 10,000 lbs vehicle loads and can be intergrated withour bridges

These boardwalks require additional engineering compared to a Pedestrian or Recreational Vehicle Boardwalk. 

Please contact us to start your Heavy-Duty Boardwalk Design

BOARDWALK INSTALLATION

Boardwalks are assembled one panel at a time. The boardwalk is fully installed with the brackets temporarily connected as the boardwalk extends.

Upon completion, the entire boardwalk is leveled and securely fastened into place.   

If the boardwalk becomes un-level due to freeze/thaw heaving or settling, the boardwalk can easily be re-leveled without disassembly.

Our expert crew can completely install up to 10 panels a day (80′) and they assembly can be done by the customer with minimal equipment.

CUSTOM BUILT BRIDGES AND BOARDWALKS