Attachment_D_-_Timber_Bridge_Design_Requirements.pdf

DESIGN/BUILD TIMBER 3-SPAN VEHICULAR BRIDGE

PART 1 – GENERAL

1.01 SCOPE

A. The Contractor shall be responsible for designing, detailing, fabrication, delivery, construction and erection of the Timber Vehicular Bridge superstructure and substructure.

1.02 UNIT PRICES

A. Payment for “Bridge Superstructure, Treated Timber” shall be compensation in full for all costs of design, supply, fabricating, and installation for Timber Vehicular Bridge superstructure. This includes nail-laminated panel superstructure, glu-lam stringers, timber rail, curb and scupper assembly, paving strips, spreader beams, all associated fasteners, plates and brackets and any other miscellaneous timber elements as required.

B. Payment for “Bridge Substructure, Treated Timber” shall be compensation in full for all costs of design, supply, fabricating, and installation for Timber Vehicular Bridge substructure. This includes timber piles and abutments, timber pile caps, all associated fasteners, plates and brackets and any other miscellaneous elements required for connections to the superstructure and to the CIP steel shell piles at the piers.

1.03 REFERENCES

A. AASHTO LRFD Bridge Design Specifications, current edition and interims B. American Wood Protection Association (AWPA) Standards, current edition C. American Wood Council (AWC) National Design Specifications (NDS) for Wood

Construction D. American Institute for Timber Construction (AITC), Timber Construction Manual

PART 2 - DESIGN

2.01 TIMBER 3-SPAN VEHICULAR BRIDGE

A. Center span shall be a timber stringer vehicular bridge and approach spans shall be a panel-lam vehicular bridge as designed and furnished by Wheeler or approved equal.

Wheeler 9531 W 78th Street, Ste. 100 Minneapolis, MN 55344

(952) 929-7854 email: info@wheeler1892.com

B. Timber stringer center span shall be designed with transverse dowel-laminated timber deck panels. Longitudinal deck panels for approach spans shall be dowel-laminated and span between supports. Deck width shall be comprised of multiple panels. Glue-laminated panels will not be allowed.

C. Ship-lapped joint connections between adjacent panels must be provided. Ship-lapped joints must be secured with drive spikes. Number and spacing of drive spikes shall be shown on design plans. Transverse spreader beams connecting multiple panels shall be provided and secured through the deck panels with bolts and locking hardware.

D. Design shall be in accordance with current AASHTO specification, all current interims and the following criteria:

1. Bridge dimensions: See bridge plan drawings.

2. All dead loads, applied dead loads, live loads, and wind loads as specified in the

AASHTO specification.

12569R19B0008 Attachment D - Timber Bridge Design Requirements mailto:info@wheeler1892.com�

3. Live loads:

AASHTO Standard HL-93 vehicle or Michigan Legal Loads positioned to produce the maximum load effect.

4. Recommended deflection criteria is L/425. Minimum deflection criteria is L/360 or as directed by the USFS.

5. Individual panel dimensions shall be determined by manufacturer.

6. Panel thickness, species and grade of timber shall be determined by manufacturer.

E. Design and materials for connection of superstructure to substructure shall be included with the superstructure and compatible with substructure design.

2.02 SUBSTRUCTURE

A. Foundation design shall be the responsibility of the bridge supplier.

B. Bridge shall be founded on timber pile abutments and steel shell CIP concrete pile piers sufficiently capped to provide foundation for the bridge. Number of piles and pile capacity shall be dictated by the bridge designer/supplier based on bridge reactions resulting from all loading conditions. Final driven length of pile to be determined by installing contractor.

C. Bridge anchorage details must be shown in the plans.

2.03 TIMBER RAILING

A. Timber rail system shall be included as part of longitudinal deck panel system.

B. Rail system shall be crash-tested to Test Level 2 (TL-2) in accordance with NCHRP

Report 350.

C. Connection of rail components must be to the deck panels only. No connection of rail components to substructures will be permitted.

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. Lumber and timber shall meet the requirements of AASHTO M168.

C. Glued laminated timber shall be manufactured in accordance with details shown on the plans and in accordance with the requirements of ANSI-A 190.1, Structural Glued Laminated Timber, latest edition using wet use adhesives. Appearance grade will be industrial.

D. 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.

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

F. Lumber and timber shall conform to the dimensions specified for either rough or surfaced stock.

G. Lumber and timber to be graded as per NFPA National Design Specifications for Wood Construction.

3.02 PRESERVATIVE TREATMENT

A. This section covers the wood preservatives and the preservative treatment of lumber and timber conforming to the Specifications as referenced or otherwise specified in the plans or special provisions. Temporary bracing shall not require preservative treatment.

B. Preservative treatment of lumber and timber shall be by the pressure process, and unless otherwise provided in the contract special provisions, be in accordance AWPA Standards and AASHTO Designation M 133.

C. 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.

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 after treatment, coat cut surfaces according to AWPA M4.

F. All Douglas Fir and other species that are difficult to penetrate shall be incised prior to treatment.

3.03 HARDWARE

A. All hardware (machine bolts, carriage bolts, drift pins, lag screws, dowels, rods, nails, spikes, washers, connectors, etc.) shall conform to ASTM 307-97.

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. All hardware shall be hot-dipped galvanized in accordance with AASHTO M111-91.

PART 4 – SUBMITTALS

4.01 PLANS AND CALCULATIONS

A. Detailed plans and design calculations for the bridge and substructure system shall be sealed by a professional engineer registered in the State of Michigan and experienced in timber bridge design and steel shell CIP concrete pile design.

B. Plans shall show all timber elements, fasteners and miscellaneous hardware required for a complete design. Detail bridge elements as necessary for construction. Provide timber species and grade, hardware specifications and design criteria on the plans including live and total deflections for each span.

C. Calculations shall verify species, size and grade of materials to be used in the manufacture of longitudinal dowel-laminated deck panels. Calculations shall include:

D. Railing design including attachment to the deck.

E. Deck and stringer design including attachment to pier caps and abutments.

F. Abutment and timber pile design.

G. Pier cap design.

H. Design of steel shell CIP concrete piles.

I. Provide a separate calculation package, sealed by a licensed structural engineer in Michigan for the bridge load ratings. Load ratings shall be completed using BRASS software or similar and provide an operating and inventory ‘rating factor’.

4.02 TIMBER CERTIFICATION

A. Solid sawn timber members shall conform to the requirements of the grading rules agency for the species, type, and grade specified in the plans or special provisions.

Glued-Laminated members shall conform to the American Institute of Timber Construction 117-201 for the combination, species, use, and appearance as specified in the plans or special provisions. A Grading Agency Certification is required on all timber material.

B. The manufacturer shall provide certifications for all timber treatments.

C. The manufacturer 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.

B. Deck panels shall be assembled with 3/8” diameter ring shank dowels. All dowels are to be simultaneously driven with equal force using a mechanical press the full length of the deck, ensuring all heads are flush with the surface of the timber plank. Multiple impact tools are not to be used to set dowels because of potential for wood fiber rupture.

C. Deck panels to be delivered to jobsite after being fully assembled at fabrication plant.

D. All plank for deck panels shall be precision end trimmed to length with ¼” underlength and no overlength tolerance permitted.

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.

B. Proper pre-drilling of holes for screws, nails, spikes, lags or bolts where necessary to avoid splitting of timber will be required.

C. Use hole saws to properly seat split rings and shear plates.

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.

5.05 PILE DRIVING

A. Actual driven length of piles and pile capacity to be documented by the contractor in accordance with MDOT standard practice and the 2012 MDOT Standard Specifications for Construction. Pile driving results shall be provided to the USFS contracting officer record.

B. Splicing of timber piles will not be allowed.