BRIDGE MATERIALS
BRIDGE MATERIALS
Axcess utilizes six basic building materials in the construction of its pedestrian bridges. Each one of these materials has its place in the bridges that Axcess designs. We have the materials expertise to guide you in making the best material choices for your unique circumstances.
Steel has been a workhorse in bridge design for nearly 100 years for good reason. It offers tremendous stiffness and strength for the price. Weathering (ASTM A588), galvanized or painted steel can be used in Axcess designs. Typically weathering steel is utilized because of the near maintenance-free characteristics as well as its rust color blends in with the nature around it. Nost steel options do not do well with high moisture or when routine salt exposure is expected.
Steel is the stiffest material available for bridge construction, which allows for long spans with less material.
Steel is very heavy, which can limit its use for remote installation locations.
Weathering steel has proven to be very corrosion resistant in environments that are relatively dry and exposure to saltwater is limited.
Steel is available in many standard shapes offering a lot of design flexibility.
Steel is a relatively inexpensive material that makes it a good choice for structural members.
Reinforced composite lumber is a decking option that offers longer life, less warping, and recycled content inputs. Reinforced composite lumber offers a good choice for bridges that are going to see a high degree of wear from snowmobiles and horses. This material comes in a wide variety of colors and thicknesses, which allows for a high degree of customization for your project.
Composite lumber has low strength and stiffness requiring thicker, heavier members for longer spans between supports.
The reinforced composite lumber board widths are one foot or less so there are a lot of pieces to install on a project. They also require a high number of fasteners.
The lightweight nature of the material means there is less material to bring to the jobsite and less dead load on the structure.
This material has excellent corrosion resistance but is susceptible to color fade from UV exposure.
Composite lumber is less costly than FRP or concrete deck options, but more expensive than treated lumber. This can be a great option for owners that are not able to pay for the full benefits of the FRP options but want a maintenance-free solution.
Aluminum is a durable and corrosion-resistant material that Axcess primarily utilizes in railings. Aluminum and FRP have a lot of similar properties in that they are both lightweight, strong, stiff, and corrosion-resistant. Axcess typically utilizes FRP versus aluminum because of FRP design flexibility for the structural elements and decks. Aluminum does have a solid fit in railings because of the cosmetic benefits that aluminum offers.
Aluminum has less strength than FRP or steel but significantly more strength than wood.
Since aluminum is so lightweight it can be fabricated into large railing assemblies that can be installed quickly in the field.
The lightweight nature of the material means there is less dead load on the structure, which requires less material in the bridge.
Aluminum is very corrosion resistant, so it provides a solution that requires little maintenance over the life of the bridge.
There are limited options for aluminum railing profiles and custom designs from aluminum are very expensive.
Standard aluminum railings are the most inexpensive railing options available.
FRP is a material comprised of a combination of thermoset polymer resin and fiberglass. This material combination provides high strength and stiffness while being very lightweight. These advantages coupled with its excellent corrosion resistance give this material tremendous advantages in pedestrian bridge applications.
FRP is significantly stiffer and stronger than wood allowing it to span further between supports reducing the amount of supports required
Since the FRP is so lightweight it can be fabricated into large assemblies that can be installed quickly in the field.
The lightweight nature of the material means less dead load on the structure, which requires less material in the bridge.
FRP can be formed to nearly any shape and size so designs are not limited to off-the-shelf configuration
FRP is a more expensive raw material than other materials choices, but that additional expense is mitigated by designing around the advantages of the material.
Treated lumber has been used as a decking material for bridges and boardwalks for the last 50+ years with mixed results. It is an inexpensive material that has decent durability but does not hold up well over the long term. It is very susceptible to warping and typically needs to be replaced multiple times over the lifespan of a bridge. Axcess typically recommends that owners utilize some of the better decking options that we offer.
Treated lumber has low strength and stiffness requiring a high amount of supports to limit the span of the decking.
Since the lumber sizes are relatively small there are a lot of supports and fasteners that need to be installed in the field.
The lightweight nature of the material means there is less dead load on the structure,which requires less material in the bridge.
This material has poor corrosion resistance and over the life of the bridge, it will need to be replaced multiple times.
Treated lumber is a low priced material but increases the cost of other parts of the bridge design because of its lack of ability to span between supports. It also needs to be replaced multiple times over the lifespan of the bridge making the total cost of ownership high.
Reinforced concrete is a material that has been around for almost 200 years and is still the most widely used construction material on the planet for good reason. It is easy to form and is a tremendous material for compression applications like abutment construction. This is really the only material option utilized for abutment construction. Axcess does not use concrete for deck or structural members because of the weight and cost of installation on the types of bridges that Axcess designs.
Concrete is a very heavy material that creates challenges with remote installation locations.
Concrete is a long-lasting material, especially for abutment construction.
Concrete construction takes a long time between the forming required and the cure time of the concrete. Weather can also create some installation challenges.
Reinforced concrete abutment construction is large part of the cost of bridge construction because it is typically the most time consuming part of bridges that Axcess constructs.
Steel has been a workhorse in bridge design for nearly 100 years for good reason. It offers tremendous stiffness and strength for the price. Weathering (ASTM A588), galvanized or painted steel can be used in Axcess designs. Typically weathering steel is utilized because of the near maintenance-free characteristics as well as its rust color blends in with the nature around it. Nost steel options do not do well with high moisture or when routine salt exposure is expected.
Steel is the stiffest material available for bridge construction, which allows for long spans with less material.
Steel is very heavy, which can limit its use for remote installation locations.
Weathering steel has proven to be very corrosion resistant in environments that are relatively dry and exposure to saltwater is limited.
Steel is available in many standard shapes offering a lot of design flexibility.
Steel is a relatively inexpensive material that makes it a good choice for structural members.
Reinforced composite lumber is a decking option that offers longer life, less warping, and recycled content inputs. Reinforced composite lumber offers a good choice for bridges that are going to see a high degree of wear from snowmobiles and horses. This material comes in a wide variety of colors and thicknesses, which allows for a high degree of customization for your project.
Composite lumber has low strength and stiffness requiring thicker, heavier members for longer spans between supports.
The reinforced composite lumber board widths are one foot or less so there are a lot of pieces to install on a project. They also require a high number of fasteners.
The lightweight nature of the material means there is less material to bring to the jobsite and less dead load on the structure.
This material has excellent corrosion resistance but is susceptible to color fade from UV exposure.
Composite lumber is less costly than FRP or concrete deck options, but more expensive than treated lumber. This can be a great option for owners that are not able to pay for the full benefits of the FRP options but want a maintenance-free solution.
Aluminum is a durable and corrosion-resistant material that Axcess primarily utilizes in railings. Aluminum and FRP have a lot of similar properties in that they are both lightweight, strong, stiff, and corrosion-resistant. Axcess typically utilizes FRP versus aluminum because of FRP design flexibility for the structural elements and decks. Aluminum does have a solid fit in railings because of the cosmetic benefits that aluminum offers.
Aluminum has less strength than FRP or steel but significantly more strength than wood.
Since aluminum is so lightweight it can be fabricated into large railing assemblies that can be installed quickly in the field.
The lightweight nature of the material means there is less dead load on the structure, which requires less material in the bridge.
Aluminum is very corrosion resistant, so it provides a solution that requires little maintenance over the life of the bridge.
There are limited options for aluminum railing profiles and custom designs from aluminum are very expensive.
Standard aluminum railings are the most inexpensive railing options available.
FRP is a material comprised of a combination of thermoset polymer resin and fiberglass. This material combination provides high strength and stiffness while being very lightweight. These advantages coupled with its excellent corrosion resistance give this material tremendous advantages in pedestrian bridge applications.
FRP is significantly stiffer and stronger than wood allowing it to span further between supports reducing the amount of supports required
Since the FRP is so lightweight it can be fabricated into large assemblies that can be installed quickly in the field.
The lightweight nature of the material means less dead load on the structure, which requires less material in the bridge.
FRP can be formed to nearly any shape and size so designs are not limited to off-the-shelf configuration
FRP is a more expensive raw material than other materials choices, but that additional expense is mitigated by designing around the advantages of the material.
Treated lumber has been used as a decking material for bridges and boardwalks for the last 50+ years with mixed results. It is an inexpensive material that has decent durability but does not hold up well over the long term. It is very susceptible to warping and typically needs to be replaced multiple times over the lifespan of a bridge. Axcess typically recommends that owners utilize some of the better decking options that we offer.
Treated lumber has low strength and stiffness requiring a high amount of supports to limit the span of the decking.
Since the lumber sizes are relatively small there are a lot of supports and fasteners that need to be installed in the field.
The lightweight nature of the material means there is less dead load on the structure,which requires less material in the bridge.
This material has poor corrosion resistance and over the life of the bridge, it will need to be replaced multiple times.
Treated lumber is a low priced material but increases the cost of other parts of the bridge design because of its lack of ability to span between supports. It also needs to be replaced multiple times over the lifespan of the bridge making the total cost of ownership high.
Reinforced concrete is a material that has been around for almost 200 years and is still the most widely used construction material on the planet for good reason. It is easy to form and is a tremendous material for compression applications like abutment construction. This is really the only material option utilized for abutment construction. Axcess does not use concrete for deck or structural members because of the weight and cost of installation on the types of bridges that Axcess designs.
Concrete is a very heavy material that creates challenges with remote installation locations.
Concrete is a long-lasting material, especially for abutment construction.
Concrete construction takes a long time between the forming required and the cure time of the concrete. Weather can also create some installation challenges.
Reinforced concrete abutment construction is large part of the cost of bridge construction because it is typically the most time consuming part of bridges that Axcess constructs.
An Axcess bridge can be broken down into four parts: abutments, structure, deck, and railing. Abutments support the bridge and hold back the soil at the approaches. The structure of a bridge is a load-carrying member that brings the load between the abutments. The deck is the surface that the user walks on and the railing keeps the user safe while on the bridge.
The decking material is the most visible and used part of the bridge. It experiences the most amount of wear and most of the degradation from the elements. This is because of its constant exposure to the elements and foot traffic. The most important elements of the deck system are cosmetics, wear resistance, safety, and longevity. Axcess designs its bridges with three primary deck materials: FRP, composite lumber, and treated lumber. FRP decking options can be customized to a wide range of colors, textures, and sizes
| CRITERIA | ASTM A588 Weathering Steel | Fiber Reinforced Polymer |
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COST |
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WEIGHT |
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LONGEVITY |
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The load-carrying structure of a bridge is the most important structural member of the bridge, but also The decking material is the most visible and used part of the bridge. The deck experiences the most amount of wear and most of the degradation from the elements. This is because of its constant exposure to the elements and foot traffic. The most important elements of the deck system are cosmetics, wear resistance, safety, and longevity. Axcess designs its bridges with three primary deck materials; FRP, composite lumber, and treated lumber. FRP decking options can be customized to a wide range of colors, textures and sizes
| CRITERIA | Fiber Reinforced Polymer | Composite Lumber | Treated Lumber |
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STRENGTH |
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WEAR RESISTANCE |
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SAFETY |
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WEIGHT |
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LONGEVITY |
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COSMETICS |
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COST |
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Although FRP and composite lumber are a more expensive raw material than treated lumber Axcess has developed relationships with these suppliers to minimize this cost premium. We have also incorporated the structural advantages that these materials offer over treated lumber to reduce the amount of structural support elements needed. These have made the installed cost of FRP decking and composite lumber a small premium over treated lumber decking.
Railing materials depend heavily on what type of bridge is being designed. FRP or steel truss bridges have the railing built into structural elements so for those types of bridges, there is no separate railing. For beam bridges, the railing options are endless and can be customized to the desired. Axcess can accommodate just about any railing design request, but this can have large impact on the pricing of the bridge. Railings are one of the most variable cost elements on a bridge and can range from $50/ft to $500/ft depending on design and materials used. Most beam bridges utilize standard aluminum railing elements because of the high corrosion resistance and the low cost. When custom railings designs are requested, they are typically designed with steel because it is much lower cost than customer aluminum fabrications.
Axcess does all its abutment construction with reinforced concrete. Concrete is one of the oldest man-made construction materials and has a proven track record for abutment construction. These abutments are typically designed with helical pile foundation supports that result in a low-cost abutment solution.
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