Specification.pdf

CIM-0909-11T-493-0909-01

Trail Bridge Repair

PART 1 – GENERAL

1.01 SCOPE

A. This work shall consist of designing, supplying and installing timber bridges AS SHOWN ON THE DRAWINGS and in accordance with these specifications.

B. The bridges are to be constructed at multiple locations near Tofte and Grand Marais Minnesota.

1.02 RELATED REQUIRED WORK

A. The Contractor shall be responsible for designing, detailing, fabricating and delivering of the entire Timber Bridges.

B. Contractor shall also be responsible for demolition and disposal of existing bridges at all sites awarded. All materials shall become the property of the Contractor except the solid stringers on the existing bridges shall be removed by the Contractor and shall remain the property of the Government. All hardware including nails, spikes and bolts shall be removed from the stringer by the Contractor prior to the Contractor delivering the stringers to the Forest Service boneyards in Tofte or Grand Marais Minnesota.

C. Work will not be permitted in the streams after September 15th due to stream restrictions. It is the Contractors responsibility to provide the proper equipment to limit the need to be in the stream to install the bridges.

1.03 UNIT PRICES

A. Payment shall be compensation in full for all costs of design, supply, and fabricating.

Payment will be processed upon successful installation of bridges.

1.04 REFERENCES

A. AASHTO Standard Specifications for Highway Bridges – current edition B. AWPA Standards – current edition C. NFPA 1991 National Design Specifications for Wood Construction.

D. ANSI/AITC A190.1-1983 and entitled “American National Standard for Wood Products

– Structural Glued Laminated Timber.”

PART 2 - DESIGN

2.01TIMBER TRAIL BRIDGES

A. Timber bridges shall match the standard Forest Service look AS SHOWN ON THE

DRAWINGS.

B. All bridges shall have 20’ long (minimum) earth ramps with wingwalls (Onion River shall be as designed by Contractor) AS SHOWN ON THE DRAWINGS incorporated into the design. Contractor shall be responsible for transporting material to site.

C. Design of glulam stringers shall be in accordance with AASHTO specifications, all current interims and the following criteria:

Bridge dimensions:

a. Onion River Bridge (Side Girder Style):

1. Clear span = 80’

2. Clear width = 13’

3. Camber shall equal 4”-8”

b. Amenda Creek Bridge:

1. Clear span = 36’

2. Clear width = 12’

3. Camber shall equal 2”-4”

c. Two Island River Bridge:

1. Clear span = 42’

2. Clear width = 12’

3. Camber shall equal 2”-4”

d. Little Devil Track River Bridge:

1. Clear span = 36’

2. Clear width = 12’

3. Camber shall equal 2”-4”

e. Carlton Creek Bridge:

1. Clear span = 40’

2. Clear width = 12’

3. Camber shall equal 2”-4”

D. All dead loads, applied dead loads, live loads, and wind loads as specified in the AASHTO specification.

E. Live loads: (worst case loading shall be used for design)

a. AASHTO pedestrian load

b. Groomer Load for Amenda Creeek, Two Island River and Little Devil

Track River bridges - 20,000 LB. GVW positioned to produce the maximum load effect, combined with a 40 psf snow load. Groomer load for stringer design shall be considered to be evenly distributed over 8' wide x 10' long area. For structural plank design the AASHTO H-10 loading shall be used.

c. Groomer Load for Onion River and Carlton Creek Bridges -12,000 LB.

GVW positioned to produce the maximum load effect, combined with a 40 psf snow load. Groomer load for stringer design shall be considered to be evenly distributed over 8' wide x 10' long area. For structural plank design the AASHTO H-5 loading shall be used.

F. Superstructure shall consist of glue-laminated stringers (or side girders) sized and spaced to accommodate design loads.

G. Both a transverse structural deck and a rough sawn longitudinal wear deck shall be provided.

H. So far as practicable all adazing, boring, chamfering, framing, gaining, mortising, surfacing and general framing shall be completed prior to delivery to site.

I. Each bridge shall have Type III Object Markers mounted at each corner by the Contractor. Materials will be supplied by the Forest Service.

PART 3 – MATERIALS

3.01 STRUCTURAL TIMBER

A. This section shall include only such lumber and timber as is part of the completed work.

It shall not include falsework, forms, bracing, sheeting or other lumber and timber used for erection purposes.

B. Only pieces consisting of sound wood free from any form of decay shall be accepted. No piece of exceptionally lightweight shall be accepted.

C. Knotholes and holes from causes other than knots shall be measured and limited as provided for knots. All visible pieces of lumber and timber having knots that are unsightly in appearance shall be rejected. Cluster knots and knots in groups are not permitted.

D. Lumber and timber meeting the requirements of Structural Timber only shall be permitted.

E. All structural timber furnished shall conform to the dimensions specified for either rough or surfaced stock.

F. All timber to be graded as per NFPA 1991 National Design Specifications for Wood Construction.

G. All timber and lumber shall be Douglas Fir or Southern Yellow Pine.

H. Lumber for solid sawn materials including decking, posts, scuppers, end closure, curbs, rails and sills shall be No. 2 or better.

I. Glued Laminated Timber

1. All structural glued laminated timber shall be as shown detailed in the Plans and as specified herein, and shall conform to the American National Standards Institute, Inc. publication designated ANSI/AITC A190.1-1983 and entitled "American National Standard for Wood Products--Structural Glued Laminated Timber."

2. Adhesives shall meet the requirements for wet-use (waterproof) using a phenol-resorcinol resin type of adhesive throughout.

3. Glued laminated stringers shall be surfaced to the AITC Industrial Appearance Grade, except that all voids on the outer face of the fascia stringers shall be filled using wood fillers or inserts.

4. Glued laminated stringers are not to be end sealed, surface sealed, or wrapped.

5. Glued laminated stringers shall be treated after fabrication. All excess glue shall be thoroughly removed from all surfaces of the stringers prior to preservative treatment.

6. Glued laminated stringers shall be marked with a qualified inspection and testing agency mark and, in addition, a certificate and test results from a qualified inspection and testing agency shall be provided to indicate conformance with the American National Standards Institute, Inc. publication designated ANSI/AITC A190.1 and entitled "American National Standard for Wood Products--Structural Glued Laminated Timber."

3.02 PRESERVATIVE TREATMENT

A. This section covers the wood preservatives and the preservative treatment of lumber, timber, piling and posts conforming to the Specifications as referenced or otherwise specified in the plans or special provisions.

B. Preservative treatment of Structural Timber and lumber shall be by the pressure process, and unless otherwise provided in the contract special provisions, be in accordance to the requirements of the specifications for Preservatives and Pressure Treatment Process for Timber, AASHTO Designation: M 133. Unless otherwise directed by the Engineer the material shall be graded prior to treatment. Material shall be accepted after treatment on the basis of its condition prior to treatment, on the basis of inspection of the treatment procedure substantiated by plant records, on the condition of the material after treatment and on absorption, penetration and visual inspection.

C. Preservatives and Preservative Treatments shall be in accordance with AWPA.

D. So far as practicable all adazing, boring, chamfering, framing, gaining, mortising, surfacing and general framing, etc., shall be done prior to treatment. If cut or drilled after treatment, coat cut surfaces according to AWPA M4.

E. All Douglas Fir or other permissible species that are difficult to penetrate shall be incised prior to treatment.

F. All girders, stringers, sills and other timber elements that come into contact with the ground shall be treated with pentachlorophenal or copper napthenate (ground-contact treatment).

G. The decking, rails, and curbs may be treated with a water based preservative for above ground contact with prior approval from the Government.

3.03 HARDWARE

A. All hardware (machine bolts, carriage bolts, drift pins, lag screws, dowels, rods, nails, spikes, washers, connectors, etc.) shall be hot-dipped galvanized and shall conform to

AASHTO.

B. Unless a Dome Head Bolt or approved equal is used, all bolt heads or tightening nuts in contact with Structural Timber and lumber shall have a washer of sufficient thickness and bearing area to ensure a minimum deformation of the contacted surface when tightened to develop not more than the maximum allowable tensile stress of that bolt

C. Bolt heads or tightening nuts in contact with metal surfaces shall have a cut washer or approved equal placed between the bolt head or nut and the metal surface.

D. NOTE that on the optional bid items the Government Furnished Material (GFM) includes a steel angle that shall be used to attach the glulam stringer to the sill using provided bolts.

PART 4 – SUBMITTALS

4.01 SEALED PLAN

A. A detailed representative bridge plan shall be included with the bid proposal. A bridge plan, specific to the site and in compliance with these specifications, sealed by a professional engineer registered in the State of Minnesota and experienced in timber bridge design, shall be submitted to the Owner within 3 weeks after award of contract.

The bridge plan shall include all details necessary for the construction of both substructure and superstructure.

4.02 TIMBER CERTIFICATION

A. All lumber and timber shall have an independent inspection prior to treatment for compliance with the grades in the Specification, and the certificate of compliance shall be submitted to the Owner subsequent to delivery of materials to jobsite.

B. The manufacture shall be regularly engaged in the production of the specified product or item and be able to furnish independent records or references of competence and satisfaction of this fact upon the request of the Owner.

PART 5 – QUALITY ASSURANCE

5.02 MANUFACTURE

A. All material shall be well manufactured. All lumber and timber shall be straight, well sawed, sawed squared at ends and have opposite surfaces parallel unless otherwise required by the plans and specifications.

5.03 WORKMANSHIP

A. Workmanship shall be first class throughout. Nails and spikes shall be driven with sufficient force to set the heads flush with the surface of the wood, thus ensuring the surface shall be free from deep or frequent hammer marks.

5.04 HANDLING

A. Lumber and timber shall be handled with sufficient care to avoid breaking through portions penetrated by treatment, and thereby exposing untreated wood. Chains, peavies, cant hooks, pickaroons, timber dogs, pike poles and other pointed tools that would burr, blemish, penetrate or permanently deform the contacted member shall not be used. Rope, rubber or fabric slings only shall be used.