Bridge Loading & Usage Diagrams
York Bridge Concepts' Timber Bridge Drawings
Bridge Loading Diagram Reference Guide
Bridge loading diagrams provide a visual reference for understanding how pedestrian, vehicular, and specialty loads may be applied to a bridge structure. These diagrams illustrate common loading configurations, including gross vehicle weight (GVW), axle loads, axle spacing, pedestrian loading, and other design considerations.
Use the diagrams below to compare common bridge loading configurations including H5, H10, HS20-44, HL-93, pedestrian loads, light vehicular loads, and custom heavy-equipment loads.
Bridge loading requirements are project-specific and should be established by the appropriate engineering professionals based on intended use, applicable standards, site conditions, and project requirements.
Not sure what these loading classifications mean? Read our Complete Guide to Bridge Load Capacity for a detailed explanation of bridge loads, capacity, HS20-44, HL-93, axle loading, and pedestrian loading.
Bridge Loading Diagram Quick Reference
| Load Type | Typical Application | Measurement |
|---|---|---|
| Pedestrian | Walking/cycling | PSF |
| 2-Ton | Light vehicles | GVW/axles |
| 5-Ton | Maintenance/light vehicles | GVW/axles |
| H5 | Light vehicular | Design vehicle |
| H10 | Vehicular | Design vehicle |
| HS20-44 | Heavier vehicular | Design truck |
| HL-93 | Highway-type design criteria | Truck/tandem + lane load |
| Custom | Specialty vehicles | Project-specific |
Loading & Usage Diagrams Resource Page
Bridge load capacity is one of the most important considerations when planning a crossing. Whether a bridge carries pedestrians, golf carts, passenger vehicles, fire apparatus, maintenance equipment, commercial trucks, or specialized heavy equipment, the structure must be engineered around the loads it is expected to support.
But selecting the appropriate bridge load is not simply a matter of choosing the highest rating available.
The right design load depends on who will use the bridge, what vehicles may cross it, how frequently those loads occur, applicable project requirements, and how the bridge may need to function in the future.
York Bridge Concepts designs pedestrian and vehicular bridges around project-specific loading requirements, from pedestrian traffic and light vehicles to HS20-44, HL-93, and specialized heavy-load applications. YBC's current engineering resources identify pedestrian loads from 85–100 PSF as well as HS20-44, HL-93, and custom vehicular loads.
Understanding loading early is an important part of the overall Bridge Design Process
How to Read a Bridge Loading Diagram
Bridge loading diagrams show how a particular design vehicle, pedestrian load, or piece of equipment applies force to a bridge. Depending on the loading condition, the diagram may identify the vehicle's total weight, number of axles, axle spacing, individual axle loads, or distributed loading.
Three measurements are especially useful when reviewing vehicular loading diagrams:
Gross Vehicle Weight (GVW)
Gross Vehicle Weight represents the total weight of the vehicle and its load. GVW provides useful context, but it should not be interpreted by itself as a bridge's maximum weight capacity.
Axle Load
Axle load represents the portion of a vehicle's weight transferred through a particular axle. Two vehicles with similar gross weights can create different structural demands depending on how their weight is distributed.
Axle Spacing
Axle spacing is the distance between the vehicle's axles. The position and spacing of axle loads influence how forces are distributed across the bridge structure.
For a deeper explanation of how these factors affect bridge capacity, visit our Bridge Load Capacity Guide.
What Is Bridge Load Capacity?
Bridge load capacity describes the loads a bridge is engineered to safely accommodate under defined design conditions.
Those loads can come from more than the vehicles or people traveling across the bridge. Engineers evaluate different forces and loading conditions when developing the structure, including the weight of the bridge itself, anticipated traffic, environmental forces, and other project-specific requirements.
For owners and project teams, however, the first practical question is usually:
What needs to cross this bridge?
The answer establishes an important starting point for determining the appropriate design criteria.
Why Bridge Loading Should Be Determined Early
Loading affects far more than the amount of weight a bridge can support.
It can influence:
- Structural member sizing
- Span capability
- Foundation requirements
- Bridge width
- Material selection
- Connections
- Deck systems
- Railings and barriers
- Construction requirements
- Cost
Changing the required design load after engineering is substantially complete can therefore require significant redesign.
That makes loading one of the questions project teams should address early in the Bridge Design Process
"I Didn't Know a Timber Bridge Could Do That!"
Most people don't know much about road ratings or loading capacities—and that's okay.
Many people underestimate what a timber bridge can accomplish.
To help educate clients and project teams, York Bridge Concepts developed a webinar focused on both vehicular and pedestrian bridge loading requirements.
The webinar covers:
- Vehicular bridge load capacities
- Pedestrian bridge load capacities
- Industry loading standards
- Project-specific loading requirements
- Heavy equipment applications
- Utility and industrial use cases
From standard highway loading to specialized applications for powerline companies, mining operations, and heavy construction equipment, timber bridges are capable of far more than many people realize.
HS20-44 Bridge Loading Diagram
HS20-44 uses a standardized three-axle design-truck configuration to evaluate vehicular loading on a bridge. The diagram below illustrates the axle loads and spacing associated with the HS20-44 design vehicle.
Quick Reference
Design Vehicle: HS20-44
Number of Axles: 3
Gross Vehicle Weight: 72,000 lbs.
Axle Loads: 8,000–32,000 lbs.
Axle Spacing: Variable based on the design configuration
HL-93 Bridge Loading Diagram
HL-93 is the vehicular live-load model associated with the AASHTO LRFD Bridge Design Specifications. The diagram below provides a visual reference for the design vehicle and distributed lane-loading considerations associated with HL-93.
Quick Reference
Loading Model: HL-93
Design Truck: 3 axles
Design Truck GVW: 72,000 lbs.
Lane Load: 640 lbs. per linear foot
Vehicle Loading: Design truck or tandem as applicable with lane loading
H5 & H10 Bridge Loading Diagrams
H5 and H10 represent lighter vehicular design-loading configurations that may be applicable to certain private, recreational, maintenance, or low-volume crossings.
H10 Loading Diagram
Quick Reference
Gross Vehicle Weight: 20,000 lbs.
Number of Axles: 2
Minimum Axle Spread: 14 ft.
Axle Loads: 4–16 kips
H5 Loading Diagram
Quick Reference
Gross Vehicle Weight: 10,000 lbs.
Number of Axles: 2
Minimum Axle Spread: 14 ft.
Axle Loads: 2–8 kips
2-Ton & 5-Ton Light Vehicle Loading Diagrams
Not every vehicular crossing requires highway-type loading. Parks, golf courses, resorts, campuses, trails, private properties, and recreational environments may require bridges designed for lighter vehicles or occasional maintenance access.
2-Ton Vehicle Loading Diagram
YBC's 2-ton loading reference represents a light two-axle vehicle configuration for appropriate project-specific applications.
Potential uses may include golf carts, light utility vehicles, and similar equipment where appropriate.
5-Ton Vehicle Loading Diagram
The 5-ton loading reference accommodates larger light-duty vehicles and equipment while remaining below heavier H-series or highway-type design loading.
Potential applications may include maintenance vehicles, utility vehicles, service equipment, and certain light vehicular crossings.
Vehicular Bridge Load Capacity
Vehicular bridges can be designed around a wide range of traffic conditions, from occasional golf carts to highway-type loading and specialized industrial vehicles.
The appropriate capacity should reflect the largest anticipated vehicles and the project's applicable engineering criteria, rather than simply the vehicles expected to use the bridge most frequently.
A residential bridge, for example, may primarily carry passenger cars but still need to accommodate fire apparatus, delivery vehicles, maintenance equipment, or construction traffic.
YBC's existing loading resources include several common vehicular loading categories.
HS20-44 Bridge Loading
HS20-44 is a widely recognized vehicular bridge loading designation used for many roadway and private infrastructure applications.
YBC's current loading diagrams identify an HS20 design truck with three axles and a gross vehicle weight of 72,000 pounds, with axle loads ranging from 8,000 to 32,000 pounds.
HS20-44 may be encountered on projects involving:
- Residential developments
- Community roadways
- Resorts
- Commercial properties
- Parks
- Golf communities
- Private roads
- Emergency vehicle access
The actual required design criteria should always be established by the project's qualified engineering team and applicable governing requirements.
HL-93 Bridge Loading
HL-93 is associated with modern AASHTO LRFD highway bridge design and combines vehicular and lane-loading considerations.
YBC's loading resources show the design truck at 72,000 pounds along with a 640-pound-per-linear-foot uniform lane load. YBC also identifies HL-93 as an available loading requirement for applicable projects.
HL-93 may be appropriate when a bridge must satisfy more demanding roadway, transportation, municipal, or project-specific requirements.
It is important not to treat HS20-44 and HL-93 as simply two different vehicle weights. They represent different design-loading frameworks, and the appropriate standard should be established by the engineer based on applicable project criteria.
H10 Bridge Loading
H10 is a lighter vehicular loading category that can be appropriate for certain lower-volume crossings.
YBC's loading resources represent H10 with a two-axle vehicle having a gross vehicle weight of approximately 20,000 pounds.
Depending on project requirements, this type of loading may be considered for crossings where heavier highway traffic is not anticipated but the bridge must accommodate vehicles beyond typical passenger traffic.
H5 Bridge Loading
H5 represents a lighter vehicular loading condition.
YBC's loading diagrams identify an H5 design vehicle with two axles and approximately 10,000 pounds gross vehicle weight.
This may be relevant for certain light-duty bridge applications, but the project team should carefully evaluate whether larger maintenance, emergency, service, or future vehicles could require access.
5-Ton Bridge Loading
A 5-ton GVW bridge can provide an intermediate solution for crossings that need to accommodate more than pedestrians or golf carts without requiring heavier highway-type loading.
YBC identifies 5-ton loading as applicable to uses such as passenger vehicles, maintenance equipment and utility vehicles where heavier commercial traffic is not expected.
Potential applications may include:
- Parks
- Golf courses
- Private properties
- Resorts
- Trails requiring maintenance access
- Campuses
- Light service crossings
The key is understanding both regular and occasional use before establishing the load.
2-Ton Bridge Loading
A 2-ton loading condition can be appropriate for lighter vehicle applications.
YBC's current diagrams represent this category with a two-axle vehicle and a gross vehicle weight of approximately 5,000 pounds.
Applications can include certain golf cart, utility, maintenance, and light-access crossings depending on the specific vehicles and engineering requirements of the project.
Vehicular Loading Standards
HL-93
Number of Axles: 3
Axle Spread:
- Minimum 14'
- Variable axle spacing from 14' to 30'
Gross Vehicle Weight:
- 72,000 lbs
- Plus 640 lbs per linear foot of uniform loading
Load Per Axle:
- 8,000 lbs to 32,000 lbs
HS20-44
Number of Axles: 3
Axle Spread:
- Minimum 14'
- Variable axle spacing from 14' to 30'
Gross Vehicle Weight:
- 72,000 lbs
Load Per Axle:
- 8,000 lbs to 32,000 lbs
H10
Number of Axles: 2
Axle Spread:
- Minimum 14'
Gross Vehicle Weight:
- 20,000 lbs
Load Per Axle:
- 4 kips to 16 kips
H5
Number of Axles: 2
Axle Spread:
- Minimum 14'
Gross Vehicle Weight:
- 10,000 lbs
Load Per Axle:
- 2 kips to 8 kips
5-Ton Vehicle
Number of Axles: 2
Axle Spread:
- Minimum 7'
Gross Vehicle Weight:
- 10,000 lbs
Load Per Axle:
- 5 kips per axle
2-Ton Vehicle
Number of Axles: 2
Axle Spread:
- Minimum 7'
Gross Vehicle Weight:
- 5,000 lbs
Load Per Axle:
- 2 kips per axle
Heavy Equipment & Specialty Vehicle Loading
York Bridge Concepts can engineer timber bridges for custom loading scenarios involving oversized vehicles and heavy industrial equipment.
70-Ton Custom Capacity
Number of Axles: 3–4
Gross Vehicle Weight: 140,000 lbs
Representative Loading:
- Steer axle and tandem axle configurations
- Tandem axle loading up to approximately 51,123 lbs combined
Volvo A25F Articulated Haul Truck
Number of Axles: 2
Axle Spread: 16.44'
Gross Vehicle Weight: 101,192 lbs
Load Distribution:
- Approximately 32,000 lbs to 69,000 lbs
Lowboy Crane Transport
Number of Axles: 5
Axle Configuration:
- Variable axle spacing
- Tridem axle arrangement
Gross Vehicle Weight: 248,000 lbs
Typical Loading:
- 18,000 lb steer axle
- Multiple tridem axle configurations
Crane Transport
Number of Axles: 3+
Variable Axle Spacing
Designed for heavy-duty crane transport applications requiring specialized load analysis and custom engineering.
Pedestrian Bridge Loading Diagrams
Unlike vehicular loads, pedestrian bridge live loading is commonly expressed as a distributed load in pounds per square foot (PSF). This accounts for people potentially occupying multiple areas of the bridge deck simultaneously.
90 PSF Pedestrian Loading
YBC's current loading resource describes 90 PSF as a pedestrian loading capacity used for regular pedestrian and cyclist traffic.
The actual required load should be established based on the project's applicable standards and intended use.
100 PSF Pedestrian Loading
Higher pedestrian loading may be appropriate where a bridge could experience larger concentrations of people.
YBC identifies 100 PSF for applications involving pedestrians, cyclists, and event crowds.
Parks, campuses, event destinations, resorts, and heavily traveled public spaces may require the project team to evaluate these higher-density conditions.
Learn how loading fits alongside span, width, accessibility, railings, and materials in our Pedestrian Bridge Design Guide.
90 PSF Pedestrian Loading Diagram
90 PSF may be encountered on pedestrian bridges serving parks, trails, greenways, recreational crossings, and other applications depending on project requirements.
100 PSF Pedestrian Loading Diagram
Higher pedestrian loading may be appropriate for bridges serving locations where greater concentrations of people are anticipated.
Planning a pedestrian crossing? Explore our Pedestrian Bridge Design Guide for span, width, accessibility, railing, material, and design considerations.
Pedestrian Loading Standards
100 PSF Pedestrian Loading
Designed for high-density pedestrian traffic applications and public-use facilities.
90 PSF Pedestrian Loading
Commonly used for:
- Parks
- Trails
- Greenways
- Recreational crossings
- Community pathways
Pedestrian Bridges With Occasional Vehicle Loading
Some pedestrian bridges also need to accommodate occasional golf carts, maintenance equipment, utility vehicles, or other limited vehicular traffic.
YBC refers to these additional project-specific requirements as sister loading. Identifying occasional vehicle use during planning allows the bridge to be designed around both its primary pedestrian function and other operational requirements.
Potential applications include parks, trails, golf courses, campuses, resorts, boardwalks, and nature preserves.
Learn more about pedestrian bridge load capacity.
York Bridge Concepts Services
Loading Analysis
Our engineering team performs comprehensive loading analyses to determine the design loads and usage conditions that will affect bridge performance.
Analysis may include:
- Vehicle weights
- Traffic volume
- Environmental conditions
- Special equipment requirements
- Site-specific loading scenarios
Advanced engineering tools and modeling techniques are used to optimize safety and performance.
Usage Studies
Understanding how users interact with a bridge is essential to successful design.
Usage studies evaluate:
- Traffic flow
- Pedestrian behavior
- Operational requirements
- Accessibility needs
- Future use scenarios
These insights help optimize bridge functionality, safety, and user experience.
Consultation Services
York Bridge Concepts provides consultation services to assist project teams with loading requirements and bridge planning.
Services include:
- Technical guidance
- Capacity recommendations
- Best practices
- Concept development
- Preliminary evaluations
- Project-specific recommendations
Custom & Heavy Equipment Bridge Loading Diagrams
Standard loading classifications do not cover every bridge application.
Utility companies, industrial properties, construction operations, mining facilities, and specialty infrastructure may require bridges engineered around specific equipment. In these cases, the actual vehicle configuration can be evaluated using factors such as gross vehicle weight, axle quantity, axle spacing, individual axle loads, and frequency of use.
70-Ton+ Custom Vehicle Loading
70-Ton Custom Vehicle Loading
Gross Vehicle Weight: 140,000 lbs.
Volvo A25F Articulated Haul Truck Loading
Gross Vehicle Weight: 101,192 lbs.
Lowboy Crane Transport Loading
Gross Vehicle Weight: 248,000 lbs.
Volvo A25F Articulated Haul Truck Loading
Gross Vehicle Weight: 143,000 lbs.
These examples demonstrate why custom loading analysis involves more than simply identifying the total weight of the equipment. Axle configuration and load distribution must also be considered by the engineering team.
Have an unusual vehicle or piece of equipment? Contact York Bridge Concepts to discuss project-specific bridge requirements.
Emergency Vehicle & Fire Truck Loading
One of the most commonly overlooked bridge-loading questions is whether emergency vehicles will ever need to cross.
A bridge serving a residential community, private property, resort, campus, or park may experience passenger vehicles during normal operations but still need to support fire apparatus or other emergency equipment.
Emergency vehicle requirements should therefore be identified with the appropriate authorities and engineering team early in the project.
Don't assume that designing for everyday traffic automatically satisfies emergency-access requirements.
Golf Cart & Maintenance Vehicle Loads
Golf courses, resorts, parks, campuses, and trails frequently require bridges that serve multiple types of users.
A crossing might primarily carry pedestrians and golf carts but occasionally need to support:
- Mowers
- Utility vehicles
- Maintenance trucks
- Landscaping equipment
- Service vehicles
- Emergency equipment
Understanding the actual equipment used by the property can help establish a more appropriate load requirement than designing around the words "golf cart bridge" or "pedestrian bridge" alone.
Custom Bridge Loading
Not every bridge fits neatly into a standard loading category.
Industrial facilities, utilities, mining operations, construction sites, large properties, and specialty infrastructure may need bridges engineered around specific vehicles or equipment.
YBC's existing resources document custom loading scenarios reaching 140,000-pound gross vehicle weights, as well as applications involving articulated haul trucks and crane transport equipment.
For these projects, engineers may evaluate factors such as:
- Gross vehicle weight
- Number of axles
- Axle spacing
- Individual axle loads
- Vehicle configuration
- Frequency of use
- Bridge span
- Traffic patterns
- Other project-specific conditions
This is where "How much does the vehicle weigh?" isn't enough information by itself.
How that weight is distributed across the bridge matters.
Bridge Section Views & Usage Configurations
Loading requirements are only one part of determining how a bridge should function. Width, lane configuration, pedestrian circulation, and intended users also influence the final bridge design.
The section views below illustrate several common bridge configurations and demonstrate how vehicular and pedestrian uses can be integrated within a crossing.
Double-Lane Vehicular Bridge with Two Attached Pedestrian Sections
Designed to accommodate vehicular traffic while providing separated pedestrian pathways.
Double-Lane Vehicular Bridge with Attached Pedestrian Section
Combines vehicular access with dedicated pedestrian circulation.
Double-Lane Vehicular Bridge
A standard two-lane vehicular bridge configuration engineered for durability and performance.
Single-Lane Vehicular Bridge with Attached Pedestrian Section
A compact bridge solution that accommodates both vehicles and pedestrians.
Single-Lane Vehicular Bridge
Designed for private roads, communities, parks, and low-volume traffic applications.
Explore our Vehicular Bridge Design Guide to learn how lane configuration, span, loading, approaches, materials, and architecture work together.
Gross Vehicle Weight vs. Axle Loading
Two vehicles can have similar gross weights while imposing very different demands on a bridge.
Gross Vehicle Weight (GVW) represents the total vehicle weight.
Axle loading describes how that weight is distributed through individual axles and ultimately into the bridge deck and structural system.
Axle spacing also influences how those loads interact with the bridge.
That is why bridge loading diagrams often specify:
GVW + number of axles + axle weights + axle spacing rather than providing only a maximum vehicle weight.
What Bridge Load Capacity Do I Need?
There isn't one correct bridge load capacity for every project.
Instead of beginning with a load designation, begin with the vehicles and users the bridge must serve.
Ask:
- Who will use the bridge every day?
- What is the heaviest vehicle expected during normal operation?
- Will delivery or service trucks cross it?
- Will maintenance equipment need access?
- Will fire or emergency apparatus cross it?
- Could construction equipment use the bridge?
- Will pedestrians or cyclists share the crossing?
- Could the property's use change in the future?
- Are there municipal, DOT, AASHTO, owner, or other project-specific requirements?
- Are there unusual or specialized vehicles that need to be evaluated?
Those answers give the engineering team a much stronger foundation for establishing the appropriate design criteria.
Should You Just Specify the Highest Bridge Load?
Not necessarily.
More capacity isn't automatically better if it provides no meaningful benefit to the project.
Increasing loading requirements can influence structural members, foundations, materials, dimensions, and potentially project cost. Conversely, underestimating loading can limit how the bridge can be used and may create much larger problems later.
The goal should be appropriate capacity—not simply maximum capacity.
The bridge should be engineered around the project's actual requirements, applicable standards, reasonable future uses, and appropriate safety considerations.
How Bridge Loads Affect Bridge Design
Loading is interconnected with many of the other decisions involved in designing a bridge.
A heavier design load can influence:
Span
Structural requirements change as loads and span lengths increase.
Foundations
Higher loads can affect the forces transferred into foundations and supporting soils.
Structural Members
Stringers, beams, connections, decking, and other components must be designed around the required loading.
Materials
Material selection and structural configuration should reflect the bridge's required performance rather than assuming one material is inherently suited to every load.
Width
A bridge designed for two lanes of traffic or attached pedestrian areas presents different loading conditions from a narrower single-lane crossing.
Cost
Changes in structural requirements can influence material quantities, foundations, engineering, transportation, and construction.
This is why bridge loading should be considered alongside the other factors in our Complete Guide to Bridge Design
Bridge Load Capacity Is About Use, Not Just Material
A common mistake is assuming that a particular bridge material automatically determines how much weight the bridge can carry.
Bridge capacity is an engineering question.
Structural configuration, member sizing, span, connections, foundations, materials, load distribution, and applicable design criteria work together to determine how the bridge performs.
YBC's existing portfolio includes bridge systems engineered for pedestrian loads, light vehicles, HS20-44, HL-93, and custom loading requirements.
The better question is therefore not:
"How much weight can this material hold?"
It is:
"How should this bridge be engineered for the loads this project requires?"
Which Bridge Loading Diagram Applies to My Project?
The appropriate bridge load depends on more than the vehicles expected to cross it every day. Project teams should also consider occasional maintenance equipment, delivery vehicles, emergency apparatus, construction traffic, pedestrian use, and potential future requirements.
Before selecting a loading classification, identify:
- The heaviest anticipated regular vehicle.
- Occasional maintenance and service vehicles.
- Fire and emergency access requirements.
- Pedestrian or cyclist use.
- Specialty equipment that may need access.
- Applicable owner, municipal, transportation, or engineering requirements.
- Reasonable future uses of the crossing.
A qualified engineering team can use that information to establish the appropriate loading criteria for the bridge.
For the full explanation, read our Bridge Load Capacity Guide.
Plan Bridge Loading Early
Bridge loading should be established during the early stages of project planning rather than after the structural concept has already been developed.
Owners, architects, landscape architects, civil engineers, developers, municipalities, and contractors should work together to identify regular traffic, occasional traffic, emergency access, maintenance equipment, pedestrian use, and potential future requirements.
York Bridge Concepts works with project teams to translate those operational requirements into a bridge solution that considers loading, span, width, site conditions, materials, constructability, aesthetics, maintenance, and long-term performance together.
Continue exploring our Bridge Design Process, Vehicular Bridge Design, or Pedestrian Bridge Design resources to see how loading fits into the larger bridge-planning process.