Introduction to Modern Timber Bridges · 2018-12-17 · Foundation Design (Designed by Consultant...
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Modern Timber Bridges Meeting Today’s Bridge Needs with Strength, Durability and Beauty Paul C. Gilham, P.E., S.E. Chief Engineer, Western Wood Structures, Inc. Wood Products Council is a Registered Provider with The American Institute of Architects Continuing Education Systems. Credit earned on completion of this program will be reported to CES Records for AIA members. Certificates of Completion for non-AIA members are available on request. This program is registered with the AIA/CES for continuing professional education. As such, it does not include content that may be deemed or construed to be an approval or endorsement by the AIA of any material of construction or any method or manner of handling, using, distributing, or dealing in any material or product. Questions related to specific materials, methods, and services will be addressed at the conclusion of this presentation. Modern Timber Bridges Meeting Today’s Bridge Needs with Strength, Durability and Beauty Learning Objectives Be Introduced to Concepts of Modern Timber Bridges. Learn How Modern Timber Bridges are Suitable for Most Bridge Applications. Learn Benefits and Constraints of Available Timber Bridge Types. Learn How to Specify Timber Bridges. Modern Timber Bridges Introduction Modern Timber Bridges Keystone Wye Rapid City, SD 1968 Advantages of Modern Timber Bridges Lightweight and strength to carry today’s loads 50-75 year life expectancy with minimal maintenance requirements Prefabrication speeds erection time. Timber is not affected by road salts or freeze-thaw cycles. Environmentally friendly Cost Competitive Aesthetically attractive
Transcript of Introduction to Modern Timber Bridges · 2018-12-17 · Foundation Design (Designed by Consultant...
Modern Timber BridgesMeeting Today’s Bridge Needs with Strength, Durability and Beauty
Paul C. Gilham, P.E., S.E.Chief Engineer, Western Wood Structures, Inc.
Wood Products Council is a Registered Provider with The American Institute of Architects Continuing Education Systems. Credit earned on completion of this program will be reported to CES Records for AIA members. Certificates of Completion for non-AIA members are available on request.
This program is registered with the AIA/CES for continuing professional education. As such, it does not include content that may be deemed or construed to be an approval or endorsement by the AIA of any material of construction or any method or manner of handling, using, distributing, or dealing in any material or product. Questions related to specific materials, methods, and services will be addressed at the conclusion of this presentation.
Modern Timber BridgesMeeting Today’s Bridge Needs with Strength, Durability and Beauty
� Learning Objectives� Be Introduced to Concepts of Modern Timber Bridges.� Learn How Modern Timber Bridges are Suitable for Most
Bridge Applications.� Learn Benefits and Constraints of Available Timber Bridge
Types.� Learn How to Specify Timber Bridges.
Modern Timber Bridges
� Introduction
Modern Timber Bridges
Keystone Wye
Rapid City, SD
1968
Advantages of Modern Timber Bridges
�Lightweight and strength to carry today’s loads
�50-75 year life expectancy with minimal maintenance requirements
�Prefabrication speeds erection time.
�Timber is not affected by road salts or freeze-thaw cycles.
�Environmentally friendly
�Cost Competitive
�Aesthetically attractive
Modern Timber Bridges
� Concepts of Modern Timber Bridges� Use of Glued-Laminated Timbers.� Modern Highway Design Codes� Structural Engineering Analysis� Computer Modeling and Fabrication Detailing� Plant Pre-fabrication� Modern Preservative Treatments
Modern Timber Bridges
� Significant increases in member strength� Laminations are dried before gluing, reducing seasoning effects.� Waterproof Adhesives.
� Conform to ASTM D2559 � Bond is stronger than wood
� Efficient use of resource� Ability to manufacture long members� Ability to manufacture curved members (camber & arches)
�Concepts of Modern Timber Bridges
�Use of Glued-Laminated Timbers.
Modern Timber Bridges
� Concepts of Modern Timber Bridges� Use of Glued-Laminated Timbers.
Modern Timber Bridges
� Concepts of Modern Timber Bridges� Use of Glued-Laminated Timbers.� Modern highway design codes.
Modern Timber Bridges
� Design Codes and Specifications� Vehicular Bridges
� AASHTO Standard Specifications for Highway Bridges� HS20-44 Vehicle (72 kip Truck with three axles)� 10,000 lb. rail load
� AASHTO LRFD Bridge Design Specifications� HL93 Vehicle (HS20-44 Vehicle plus 640 plf lane
load)� Crash Tested Rail Systems
� Geometry (Lane widths, clearances, etc.)� Load Distribution � Wind & Seismic loads
�Concepts of Modern Timber Bridges
Modern Timber Bridges
� Design Codes and Specifications� Vehicular Bridges
Modern Timber Bridges
� Design Codes and Specifications� Vehicular Bridges
Modern Timber Bridges
� Design Codes and Specifications� Vehicular Bridges
Modern Timber Bridges
� Design Codes and Specifications� Pedestrian Bridges
� “AASHTO Guide Specifications for Pedestrian Bridges”� 85 psf Live Load� 50 psf Wind Load� Suggested Vehicle Loads:� Unless access is prevented or agency specified vehicle.� 6 – 10 ft. width: 10,000 lb Truck� Over 10 ft. width: 20,000 lb Truck� 42” or 54” high rails with 6” & 8” opening. (50 plf. lateral load)
� International Building Code� 100 psf Live Load� Wind and Seismic based on local requirements� 42” high rails with 4” openings. (50 plf. lateral load)
�Concepts of Modern Timber Bridges
Modern Timber Bridges
� Use of Glued-Laminated Timbers.� Modern highway design codes.� Structural Engineering Analysis.
� Computer analysis of structures� Ability to optimize bridge design� Identifies trouble locations� Greatly reduces design time
�Concepts of Modern Timber Bridges
Modern Timber Bridges
� Concepts of Modern Timber Bridges� Structural Engineering Analysis.
Modern Timber Bridges
� Concepts of Modern Timber Bridges� Use of Glued-Laminated Timbers.� Modern highway design codes.� Structural Engineering Analysis.� Computer Modeling and Fabrication Detailing.
� Computer Assisted Drafting � Solid Modeling� Ability to interface with fabrication equipment
Modern Timber Bridges� Concepts of Modern Timber Bridges
� Computer Modeling and Fabrication Detailing.
Modern Timber Bridges
� Concepts of Modern Timber Bridges� Use of Glued-Laminated Timbers.� Modern highway design codes.� Structural Engineering Analysis.� Computer Modeling and Fabrication Detailing.� Plant Pre-fabrication.
� All cuts and bores are fabricated� Proper tools and equipment to fabricate large members� Allows quick jobsite assembly� Protects treating envelope and prevents jobsite contamination.
Modern Timber Bridges� Concepts of Modern Timber Bridges
� Plant Pre-fabrication.
Modern Timber Bridges
� Concepts of Modern Timber Bridges� Use of Glued-Laminated Timbers.� Modern highway design codes.� Structural Engineering Analysis.� Computer Modeling and Fabrication Detailing.� Plant Pre-fabrication.� Modern Preservative Treatments.
� EPA registered pesticides� Effective prevention of decay and Insect attack� Complete treatment envelope
Modern Timber Bridges� Concepts of Modern Timber Bridges
� Modern Preservative Treatments.
Modern Timber Bridges� Concepts of Modern Timber Bridges
� Modern Preservative Treatments.
Modern Timber Bridges� Concepts of Modern Timber Bridges
� Modern Preservative Treatments.
�Chemical Minimization
�Product cleanliness
�Inspection and rejection
�Fixation
�Field Installation Guidelines
�BMP Quality Control & Certification
Modern Timber Bridges� Concepts of Modern Timber Bridges
� Modern Preservative Treatments.
Treated without BMPs Treated with BMPs
Modern Timber Bridges� Concepts of Modern Timber Bridges
� Modern Preservative Treatments.
Modern Timber Bridges� Concepts of Modern Timber Bridges
� Modern Preservative Treatments.
Modern Timber Bridges� Concepts of Modern Timber Bridges
� Modern Preservative Treatments.
Modern Timber Bridges
� Bridge Types (Benefits and Constraints)� Boardwalks� Longitudinal Deck Bridges� Girder Bridges� Side Girder Bridges� Truss Bridges� Arch Bridges� Suspension Bridges � Covered Bridges
Modern Timber Bridges
� Bridge Types (Benefits and Constraints)� Boardwalks
� Used in wetlands and sensitive areas.� Used with multiple short spans. (8’ to 12’ lengths)� Light pier foundations (drilled in concrete piers, timber piles,
premanufactured pin foundations, helical anchors)
Modern Timber Bridges
� Pedestrian Bridges� Design Codes and Specifications� Bridge Types (Benefits and Constraints)
� Boardwalks
Modern Timber Bridges
� Pedestrian Bridges� Design Codes and Specifications� Bridge Types (Benefits and Constraints)
� Boardwalks
Modern Timber Bridges
� Pedestrian Bridges� Design Codes and Specifications� Bridge Types (Benefits and Constraints)
� Boardwalks
Driven Timber Piles Helical Anchor Installation
Modern Timber Bridges
� Pedestrian Bridges� Design Codes and Specifications� Bridge Types (Benefits and Constraints)
� Boardwalks
Diamond Pier Foundation
Modern Timber Bridges
� Vehicular Bridges� Design Codes and Specifications� Bridge Types (Benefits and Constraints)
� Longitudinal Deck Bridges� Spans from 10’ to 40’� Low Clearance Requirements� Made from glued laminated deck panels� Easy installation
Modern Timber Bridges
� Vehicular Bridges� Design Codes and Specifications� Bridge Types (Benefits and Constraints)
� Longitudinal Deck Bridges (Slab type Bridge)
Modern Timber Bridges
� Bridge Types (Benefits and Constraints)� Girder Bridges
� Most Common Bridge Structure� Longitudinal girders with transverse deck panels� Spans to 80 ft +
Modern Timber Bridges
� Bridge Types (Benefits and Constraints)� Girder Bridges
Modern Timber Bridges
� Bridge Types � Girder Bridges
Diaphragms & Rod BracingGlulam deck and rails
Modern Timber Bridges
� Bridge Types� Girder Bridge
Modern Timber Bridges
� Vehicular Bridges� Design Codes and Specifications� Bridge Types (Benefits and Constraints)
� Girder Bridge
Modern Timber Bridges
� Vehicular Bridges� Design Codes and Specifications� Bridge Types (Benefits and Constraints)
� Girder Bridge
Modern Timber Bridges
� Bridge Types � Side Girder Bridges
� Used where clearance below bridge is limited.� Spans to 80 ft +� Requires floor beams and purlin secondary framing. (not ledgers)
Modern Timber Bridges
� Bridge Types � Side Girder Bridges
Modern Timber Bridges
� Pedestrian Bridges� Design Codes and Specifications� Bridge Types (Benefits and Constraints)
� Side Girder Bridges
Modern Timber Bridges
� Bridge Types � Truss Bridges (Bowstring or Parallel Chord)
� Spans from 85’ to 200’� Light weight members� Significantly more fabrication and connecting steel� More complicated erection procedures� Truss can be above or below deck
Modern Timber Bridges
� Pedestrian Bridges� Design Codes and Specifications� Bridge Types (Benefits and Constraints)
� Truss Bridges (Pony Truss, Bowstring or Parallel Chord)
Pony Truss Bridge
8’ x 100’
Beaverton, Oregon
Modern Timber Bridges
� Pedestrian Bridges� Design Codes and Specifications� Bridge Types (Benefits and Constraints)
� Truss Bridges (Pony Truss, Bowstring or Parallel Chord)Bowstring Truss Bridge
10’ x 135’
Beaverton, Oregon
Modern Timber Bridges
� Bridge Types � Truss Bridges (Pony Truss, Bowstring or Parallel Chord)
Modern Timber Bridges
� Bridge Types � Truss Bridge
Martis Creek Bridge
32’ x 147’ Two Lane Vehicle Bridge
Truckee, CA
Modern Timber Bridges
� Bridge Types � Truss Bridges
Cosumnes River Bridge
10’ x 410’
Rancho Murieta, CA
Modern Timber Bridges
� Bridge Types (Benefits and Constraints)� Arch Bridges
� Spans from 100’ to 200’� Larger Members than trusses� Less fabrication and connection steel� More complicated erection procedures� Arches can be above or below deck� More complicated foundations
Modern Timber Bridges
� Bridge Types � Arch Bridges
Hopland Casino Bridge - 18’ x 180’ w/ 15 ton truck
Hopland, California
Modern Timber Bridges
� Bridge Types � Arch Bridges
Modern Timber Bridges
� Bridge Types� Arch Bridges
Modern Timber Bridges
� Bridge Types (Benefits and Constraints)� Arch Bridges
Modern Timber Bridges
� Bridge Types (Benefits and Constraints)� Arch Bridges
Centennial Garden Bridge - 8’ x 100’
Longview, WA
Modern Timber Bridges
� Bridge Types (Benefits and Constraints)� Arch Bridges
South Prairie Creek/Lower Burnett Road Bridge - 14’ x 398’
Buckley, WA
Modern Timber Bridges
� Bridge Types� Arch Bridges
Cascade Highlands Bridge
10’ x 80’
Bend, OR
Modern Timber Bridges
� Bridge Types (Benefits and Constraints)� Suspension Bridges (Caternary or Cable Stayed)
� Spans from 100’ to 400’� Very small members� Cable and Tower Designs are significant� Must include cable anchorage to foundations to the the longitudinal
elements.
Modern Timber Bridges
� Bridge Types� Suspension Bridges (Caternary or Cable Stayed)
Modern Timber Bridges
� Bridge Types� Suspension Bridges (Caternary or Cable Stayed)
Modern Timber Bridges
� Bridge Types� Suspension Bridges (Caternary or Cable Stayed)
Hiroshima Airport Bridge – Hiroshima, Japan 16’ x 475’
Modern Timber Bridges
� Bridge Types (Benefits and Constraints)� Covered Bridges
� Special Case of Truss or Girder Bridge
Alpental Ski Bridge - 10’x185’ three span parallel chord truss bridge with roof
Modern Timber Bridges
� Bridge Types (Benefits and Constraints)� Covered Bridges
� Special Case of Truss or Girder Bridge
Modern Timber Bridges
� Specifying Timber Bridges� Length, Clear Span, Center to Center of Abutments, Out to out.
� Consider Scour Potential, 100-year Flood Elevation & Stream Protection
� Width. (Based on anticipated traffic) � Governing Building Code. (Determines Vehicle Load, Live Load,
Wind and Seismic Loads)� Bridge Style (Include slope and/or camber).� Rail Configuration.� Clearance Constraints, if any.� Pre-qualified bridge supplier.� Calculations & Shop Drawings stamped by Professional Engineer.� Certificates of Conformance for glulam, steel shapes, hardware and
preservative treating.� Foundation Design (Designed by Consultant or Bridge Supplier)
Modern Timber Bridges
� Recap:
� Modern Timber Bridges combine the use of glued-laminated timbers, the most recent highway design codes, computer assisted analysis and detailing methods and environmentally appropriate preservative treatments to provide structures capable of carrying today’s design loads and durable enough for a 75 year life expectancy.
� Several common structural systems including slabs, beams, trusses, arches, and suspension structures can be implemented in constructing timber bridges.
� Specifying a timber bridge includes identifying length and width required, the governing building codes, bridge and rail style preferred and quality assurance measures.
Modern Timber Bridges
