Specifications.docx

Hiawatha National Forest – Trail Bridges The Hiawatha National Forest is soliciting quotations for the provision of three modular pre-engineered trail bridges.

Delivery date and time will require pre-coordination in order to have equipment on-hand for off-loading. A loading dock is NOT available.

Design Criteria:

The pre-engineered bridges shall be designed in accordance with AASHTO’s LRFD Guide Specifications for the Design of Pedestrian Bridges as amended by Forest Service Handbook 7709.56b – Transportation Structures Handbook Ch. 80 – Trail Bridge Design which is included as an attachment to this solicitation; sections of the Handbook that do not apply to this solicitation have been greyed out.

General Bridge Requirements:

1. Planned usage: Pedestrian with occasional winter pedestrian use.

2. Bridge Clear Travel Width: 42”.

3. Bridge Top Rail Height: 42” above decking

4. Bridge Intermediate Rails: Centered between top rails and decking.

5. Curb/Kick rail: Not required.

6. Basic Wind Speed (From ASCE 7): 90 mph.

7. Surface roughness (Wind exposure - All sites - ASCE 7 Criteria): Surface roughness B.

8. Ground snow load: 70 psf.

9. Maximum member size/weight: 10’ long, 150 lbs.

10. Modular: Bridge components shall be supplied as a complete site assembled package on a site prepared foundation system which is not the responsibility of the bridge manufacturer, site assembly is not the responsibility of the manufacturer. Components will be field connected by pins, bolts, or other standard connections requiring no welding or fabrication of parts after receipt of components.

11. Bridge Materials:

1. Bridge main structural elements shall be constructed of weathering steel, aluminum, or FRP composites.

a. Materials used will be decay, UV, heat, and corrosion resistant without the use of exterior coatings requiring routine repair or replacement.

b. Secondary members shall have similar resistance to deterioration; if differing materials are utilized for bridge components the manufacturer shall certify the materials are compatible and will not contribute to accelerated deterioration – galvanic corrosion, polymer degradation, etc.

c. The structures will be site assembled on site constructed foundations; the manufacturer shall provide guidance on acceptable materials or the need for isolation from common substructure materials – i.e. treated lumber, concrete, steel, and soil/aggregate.

d. Decking – ribbed, wood textured, grit, or other slip resistant type finish.

12. Design Submittals:

1. The manufacturer shall furnish sealed design calculations prepared by the licensed professional engineer responsible for the design. Load combinations determined to control design of bridge elements shall be highlighted.

2. The manufacturer shall furnish sealed plans for the bridge prepared by the licensed professional engineer responsible for the design. Plans shall include the following:

i. Design loads and site attributes – Live loads, dead loads, exposure, etc.

ii. Loads that will be transmitted from the bridge superstructure to the substructure units.

iii. Bridge parts list and diagram including any instructions for assembly including any constraints on temporary supports and/or bracing during construction.

iv. Diagram showing required area of bearing on the superstructure to the substructure.

13. Bridge aesthetics: A structure that blends with the natural environment that they will be located is preferred – forested, natural areas, in remote and/or rural areas. This is a non-mandatory element but will be utilized in selecting a quotation for contract award in the case of similar proposals.

Schedule of Items – include all costs including freight to the delivery address for each bridge; the intent is to procure all three bridges but availability of funds will determine the ability to award all items.

Manufacturer’s Requirements:

1. 10 years’ experience manufacturing pre-engineered bridges.

Offer documents:

1. Provide firm fixed prices for each structure requested.

2. Provide informational sheets for the proposed structures including any options that were utilized in bid preparation – also include option items that are available but not included.

3. Provide warranty information for modular bridges.

4. Provide information for similar structures manufactured for other clients including references for recent clients.