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Frequently Asked Questions
1. How can a railing or lighting be mounted on an existing bridge parapet and still meet or exceed highway design loads?
2. What is the quickest and cost effective way to pour new pier caps when rehabbing existing piers for new decks.
3. When rehabbing concrete bridge decks, what is the safest and easiest method to remove the old deck when free from the beams.
4. What is the quickest way with least disruption of traffic to replace a section of damaged parapet or center medium on a structure.
5. How can a railing or lighting be mounted on an existing bridge parapet and still meet or exceed highway design loads?
6. What is the quickest and cost effective way to pour new pier caps when rehabbing existing piers for new decks?
7. When rehabbing concrete bridge decks, what is the safest and easiest method to remove the old deck when free from the beams?
8. What is the quickest way with least disruption of traffic to replace asection of damaged parapet or center medium on a structure?
9. How long will a timber vehicular bridge really last?
10. Can a timber vehicular bridge withstand heavy, continuous traffic?
11. Because of permitting regulations, I can't drive piling in a protected area. How can a bridge cross it?
12. Do you recommend screws or nails for fastening the guiderail to the bridge?
13. What kinds of projects are timber vehicular bridges best suited for?
14. What does HS20-44 mean?
15. How long can a timber bridge be?
16. How wide should my bridge be?
17. I need a bridge with a pedestrian walkway that will have children walking over it regularly. Is the treatment on wood safe for this type of application?
18. Isn't building wooden bridges harmful to the environment?
19. Can thin polymer concrete overlays be used to waterproof an existing concrete bridge deck?
20. Can a polymer concrete overlay be placed over any type of repair material that has been used to repair bridge deck spalling?
21. Do polymer concrete overlays require special equipment for their installation?
22. If a concrete bridge deck has cracking and has been treated with linseed oil or a saline solution can a polymer crack sealer be applied.
23. Can I use high-molecular weight methacrylate to seal cracks in vertical cracks in a concrete structure?
24. If I treat concrete cracks with high-molecular weight methacrylate will the repair be perminate?
25. Should high-molecular weight methacrylate crack sealers be considered a wearing surface if applied to the entire surface of a concrete bridge deck?
26. Can polymer concrete be used for spall, expansion joint and bearing pad rehabilitation?
27. If I want to use a polymer concrete overlay do I have different types of materials to choose from?
1. Q: How can a railing or lighting be mounted on an existing bridge parapet and still meet or exceed highway design loads?
A:
When retro fitting and mounting any items on an existing structure, the strongest method is to use a high strength chemical anchor system, with high strength anchors.
Supplied by Kelken Construction Systems
2. Q: What is the quickest and cost effective way to pour new pier caps when rehabbing existing piers for new decks.
A:
Drilling and installing rebar vertically in the pier by chemically anchoring, then the additional reinforcing is attached for the pour.
Supplied by Kelken Construction Systems
3. Q: When rehabbing concrete bridge decks, what is the safest and easiest method to remove the old deck when free from the beams.
A:
Calculate the weight of the deck sections and size high strength “O”-ring or hook bolts and anchor them on both end of the sections with structural chemical anchoring resin, and lift off the bridge.
Supplied by Kelken Construction Systems
4. Q: What is the quickest way with least disruption of traffic to replace a section of damaged parapet or center medium on a structure.
A:
After the damaged section is removed and the deck is clear, size and cut a section of pre-cast parapet or center medium barrier and drop into place, then anchor to the deck with a high strength chemical anchor system.
Supplied by Kelken Construction Systems
5. Q: How can a railing or lighting be mounted on an existing bridge parapet and still meet or exceed highway design loads?
A:
When retro fitting and mounting any items on an existing structure, the strongest method is to use a high-strength chemical anchor system with high-strength anchors.
6. Q: What is the quickest and cost effective way to pour new pier caps when rehabbing existing piers for new decks?
A:
Drilling and installing rebar vertically in the pier by chemically anchoring, then the additional reinforcing is attached for the pour.
7. Q: When rehabbing concrete bridge decks, what is the safest and easiest method to remove the old deck when free from the beams?
A:
Calculate the weight of the deck sections and size high strength “O” ring or hook bolts and anchor them on both ends of the sections with structural chemical anchoring resin and lift off the bridge.
8. Q: What is the quickest way with least disruption of traffic to replace asection of damaged parapet or center medium on a structure?
A:
After the damaged section is removed and the deck is clear, size and cut a section of precast parapet or center medium barrier and drop into place, then anchor to the deck with a high-strength chemical anchor system.
9. Q: How long will a timber vehicular bridge really last?
A:
While the life of your specific bridge depends upon various factors, the U.S. Forest Service notes that more than 1,000 timber bridges at least 90 years old are still in service throughout the United States. Furthermore, since the quality and technology of pressure treatment has greatly increased in the last 90 years, you can expect that a bridge built today would last even longer. Choosing a builder who understands that superior materials, expert craftsmanship methods and the proper design work together to increase longevity is the best way to make sure your bridge will stand the test of time.
Supplied by York Bridge Concepts
10. Q: Can a timber vehicular bridge withstand heavy, continuous traffic?
A:
Timber vehicular bridges are built to meet or exceed AASHTO standards of HS20-44, the most commonly accepted standard for highway safety today. As another assurance, be sure to ask for a written structural warranty on your timber bridge.
Supplied by York Bridge Concepts
11. Q: Because of permitting regulations, I can't drive piling in a protected area. How can a bridge cross it?
A:
First, choose a builder with experience in this type of situation. A qualified builder can most often customize the design of the bridge specifically for your project and crossing needs, taking into account any environmental or permitting challenges. In addition, timber pilings can be driven into almost any environment, and are often approved for permits when steel pilings are not.
In general, freespan designs (no intermediate supports) are used for shorter distances, while a combination span (a combination of freespan and pile supported sections in the non-protected area) are usually used for larger, longer crossings and are a more economical choice.
Supplied by York Bridge Concepts
12. Q: Do you recommend screws or nails for fastening the guiderail to the bridge?
A:
Builders have found from experience that screws are better in this situation in order to minimize loosening of the connections. Such attention to detail is one way to increase the longevity and decrease the maintenance required on the bridge.
Supplied by York Bridge Concepts
13. Q: What kinds of projects are timber vehicular bridges best suited for?
A:
We firmly believe that timber vehicular bridges are right for virtually any setting. Many customers use a timber bridge as the entrance to a new development - the timber helps to enhance the natural setting and evokes a feeling of warmth. The feel of timber bridges are immediately recognizable by your guests.
Many other customers use timber bridges or boardwalks to cross wetlands areas. Generally speaking, difficult or sensitive crossings are better suited to on-site construction with timber. In addition, construction of the bridge from the deck level will ensure that no heavy machinery enters the protected wetlands area. An experienced builder can cross virtually any obstacle, including lakes/rivers, ponds, creeks/streams, ravines, roadways and wetlands areas.
Supplied by York Bridge Concepts
14. Q: What does HS20-44 mean?
A:
HS20-44 refers to the loading specifications set forth by AASHTO, an agency that governs highway design and loading. Essentially, HS20-44 capacity means that the bridge or highway is able to safely accommodate a 3-4 axle vehicle, such as a large semi-truck and trailer. Most on-site bridge construction companies build timber vehicular bridges to meet or exceed these AASHTO requirements.
Supplied by York Bridge Concepts
15. Q: How long can a timber bridge be?
A:
When designed and built by experienced builders, timber bridges can be built to virtually any length and still maintain their structural integrity.
Supplied by York Bridge Concepts
16. Q: How wide should my bridge be?
A:
For safety and stability during construction and beyond, builders recommend standard minimum widths for pedestrian and cart/maintenance bridges - the width of a bridge must increase in direct proportion to the height. Vehicular bridges usually exceed the required width, and therefore do not have an absolute minimum.
Pedestrian bridge: Minimum width 6 ft, maximum height 8 ft.
Cart/Maintenance bridge: 10 ft high = minimum 8 ft wide, 20 ft high = minimum 10 ft wide, 35 ft high = 12 ft wide (standard width).
Timber Vehicular bridge: Standard single lane width = 16 ft, Double lane = 32 ft.
Supplied by York Bridge Concepts
17. Q: I need a bridge with a pedestrian walkway that will have children walking over it regularly. Is the treatment on wood safe for this type of application?
A:
Absolutely. All treatments typically used in timber bridge construction is EPA approved, including ACQ and CCA treated timber. At your request, many builders can also use other materials in construction
Supplied by York Bridge Concepts
18. Q: Isn't building wooden bridges harmful to the environment?
A:
No. The primary material in timber bridge construction is Southern Yellow Pine or Douglas Fir. Wood is the only sustainable and renewable building material - it is a renewable resource unlike steel, concrete, or plastic. North America has more acreage of trees than it did even 70 years ago, due to responsible forestry practices. In addition, according to the Southern Pine Council, "Wood contributes far fewer greenhouse gas emissions than its non-renewable counterparts, steel and concrete. Although wood products make up 47% of all raw materials made in the United States, its share of energy consumption during production is only 4% of all manufactured materials."
Supplied by York Bridge Concepts
19. Q: Can thin polymer concrete overlays be used to waterproof an existing concrete bridge deck?
A:
Yes, thin polymer overlays will waterproof a concrete bridge deck as long as the overlay application has sufficient thickness--3/8 in. min. Multiple coat polymer overlays will require three application coats to obtain this thickness.
Supplied by Transpo Industries
20. Q: Can a polymer concrete overlay be placed over any type of repair material that has been used to repair bridge deck spalling?
A:
Polymer concrete should not be applied on magnesium phosphate patches, since bonding will be minimal
Supplied by Transpo Industries
21. Q: Do polymer concrete overlays require special equipment for their installation?
A:
Many of the new polymer concrete overlays are designed to be applied with standard concrete mortar mixers and hand tools.
Supplied by Transpo Industries
22. Q: If a concrete bridge deck has cracking and has been treated with linseed oil or a saline solution can a polymer crack sealer be applied.
A:
Any bridge deck that has been treated with either of these products will have questionable results if sealed with a polymer. The polymer performance can be greatly increased if the bridge deck is cleaned with high pressure water and allowed to dry before applying the polymer material.
Supplied by Transpo Industries
23. Q: Can I use high-molecular weight methacrylate to seal cracks in vertical cracks in a concrete structure?
A:
High-molecular weight methacrylates are primarily designed to be applied on horizontal surfaces and will fill cracks thru gravity, however they can be applied to vertical cracks with the use of injection ports and injection equipment.
Supplied by Transpo Industries
24. Q: If I treat concrete cracks with high-molecular weight methacrylate will the repair be perminate?
A:
These materials once cured will permanently seal cracks if the crack movement is within the limits of the polymer material. High-molecular weight methacrylate materials will not compromised by water like many of the other materials used to seal cracks.
Supplied by Transpo Industries
25. Q: Should high-molecular weight methacrylate crack sealers be considered a wearing surface if applied to the entire surface of a concrete bridge deck?
A:
High-molecular weight methacrylates are designed to heal and seal cracks in concrete and strengthen the surface layer. However, all residual material on the surface will be worn off by normal traffic in a relatively short period of time.
Supplied by Transpo Industries
26. Q: Can polymer concrete be used for spall, expansion joint and bearing pad rehabilitation?
A:
Polymer concrete material systems are formulated to be used for all type of concrete bridge deck repair.
Supplied by Transpo Industries
27. Q: If I want to use a polymer concrete overlay do I have different types of materials to choose from?
A:
Polymer concrete is a generic description of a family of products which contain epoxies, methacrylates, high-molecular weight methacrylates, polyester and latex. Each of the different materials has specific installation requirements for successful application.
Supplied by Transpo Industries
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