Timber Bridge
Load Capacities & Uses

What uses do timber bridges support?


Timber Bridge Load Capacities & Uses

Our timber bridges can be designed and built for any capacity and use.

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Timber bridges are great for both vehicular and pedestrian use. The majority of the vehicular bridges we’ve built are designed to general highway standards for traffic including semi-trucks, which does tend to surprise people. In addition, all vehicular bridges can be designed specifically to meet the needs of heavier loads, the options are far and wide, just ask! As for the pedestrian bridges we’ve built everything from nature’s best boardwalks to luxury waterfront amenities to soaring free spans, each designed to the national standards for safety. Like our vehicular bridges, our pedestrian bridges can also be designed to accommodate greater crowds, enhanced loading for occasional use by vehicles, or the most common request is to allow for golf cart use. So, if you have a use in mind, we’ve got a capacity to match. These are some definitions, diagrams, and even charts to help you define the right bridge for your needs.

Can I drive a firetruck over a timber bridge?


Our standard HS20 design will accommodate most fire trucks. Occasionally, an HL-93 will be necessary.

Can a timber bridge be used for heavy weight equipment and large specialty vehicles?


We can design a timber bridge to accomodate heavy duty equimpment. In the case of our project, Big Bend in Apollo Beach, FL, we designed and built three vehicular bridges specialty rated at 73 Ton GVW to accommodate utility vehicles used for repairing power lines at a local energy facility. If you have a diagram of a specialty vehicle with a defined axle spread, we can determine capacity and custom design a timber bridge for you.
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73-Ton GVW Specialty Load Rating
Vehicle Diagram Provided

Standard Vehicular Use


This category is based on regular usage of the bridge by vehicles up to a semi-tractor-trailer. The most common loading capacity for Standard Vehicular Use is the HS20 Truck Loading. They are typically utilized for private and public roadways. Ultimately, a loading capacity is determined by largest vehicle for anticipated regular use, for example an HS20 supports a typical semi-tractor-trailer weighing 72,000 lbs. To see more about HS Truck Loadings for maximum weights and weight distribution see the associated loading diagrams and charts.

Load capacity
Axle Quantity
Axle Spread
Gross Vehicular Weight (GVW)
Per Axle Loading
CAD Files
Project Links

HS20

3 Axles

Min 14′ Axle Spread, 14′ to 30′ Variable Axle Spread

72k lbs / 36 Tons

8k lbs – 32k lbs – 32k lbs


HL93

3 Axles

Min 14′ Axle Spread, 14′ to 30′ Variable Axle Spread

72k lbs / 36 Tons + 640 lbs per linear foot of uniform loading

8k lbs – 32k lbs – 32k lbs + 640 lbs per linear foot of uniform loading

Lightweight Vehicular Use


This category is based on regular usage of the bridge by vehicles up to a large pick-up truck or SUV. The most common loading capacities for Lightweight Vehicular Use bridges are the H5 & H10 Truck Loadings. They are typically utilized for driveways, trails, private access roads, maintenance paths, or similar. Ultimately, a loading capacity is determined by largest vehicle for anticipated regular use, for example an H10 would be used when Emergency Access for an Ambulance or similar is required. To see more about H Truck Loadings for maximum weights and weight distribution see the associated loading diagrams and charts.

Load capacity
Axle Quantity
Axle Spread
Gross Vehicular Weight (GVW)
Per Axle Loading
CAD Files
Project Links

H5

2 Axles

Min 14′ Axle Spread

10k lbs / 5 Tons

2 kips (2k.lbs) –  8 kips (8k.lbs)


H10

2 Axles

Min 14′ Axle Spread

20k lbs / 10 Tons

4 kips (4k.lbs) –
16 kips (16k.lbs)

Heavy Weight Equipment & Large Specialty Vehicle Use


This category is based on regular usage of the bridge by a unique vehicle with special loading considerations, that is atypical of all commonly defined truck loading capacities. A custom truck loading capacity can be designated to support the maximum gross vehicular weight and weight distribution of most oversized or unique truck loads. Pictured below are examples of vehicles that we used to custom design timber bridges.

Custom capacity
Axle Quantity
Axle Spread
Gross Vehicular Weight (GVW)
Per Axle Loading

70 Ton GVW

3-4 Axles

N/A

140k lbs / 70 Tons

81,831 lbs (Steer Axle & Tandem Axle, lbs/wheel undefined) – 51,123 lbs (Tandem Axle 25,561.5 lbs/wheel)


Volvo A25F Articulated Load

2 Axles

16.44′

101,192.2 lbs

32,077.3 lbs – 69,115 lbs (Tandem Axle 34,557.5 lbs/wheel)


Low Boy Crane Transport

5 Axles

Min 14′ Axle Spread; 14′ to 26’7″ Variable Axle Spread; 4.5′ – 5′ Variable Tridem Axle Spread

248,000 lbs

18k lbs – (4) 57.6k combined lbs per axle (Tridem Axles 19,200 lbs/wheel)


Crane Transport

3 Axles

Min 16′ Axle Spread; 16′ to 31’4″ Variable Axle Spread; 4.5′ – 5′ Variable Tridem Axle Spread

15,500 lbs – (2) 63,750 combined lbs per axle (Tridem Axles 21,250 lbs/wheel)

18k lbs – (4) 57.6k combined lbs per axle (Tridem Axles 19,200 lbs/wheel)

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Glossary

General Terminology Definitions


H vs. HS

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Capablities & Design-Build Process

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