DOCSLIB.ORG

Timber Bridges Design, Construction, Inspection, and Maintenance

Total Page：16

File Type：pdf, Size：1020Kb

Download full-text PDF Read full-text
Timber Bridges Design, Construction, Inspection, and Maintenance Timber Bridges Design, Construction, Inspection, and Maintenance Michael A. Ritter, Structural Engineer United States Department of Agriculture Forest Service Ritter, Michael A. 1990. Timber Bridges: Design, Construction, Inspection, and Maintenance. Washington, DC: 944 p. ii ACKNOWLEDGMENTS The author acknowledges the following individuals, Agencies, and Associations for the substantial contributions they made to this publication: For contributions to Chapter 1, Fong Ou, Ph.D., Civil Engineer, USDA Forest Service, Engineering Staff, Washington Office. For contributions to Chapter 3, Jerry Winandy, Research Forest Products Technologist, USDA Forest Service, Forest Products Laboratory. For contributions to Chapter 8, Terry Wipf, P.E., Ph.D., Associate Professor of Structural Engineering, Iowa State University, Ames, Iowa. For administrative overview and support, Clyde Weller, Civil Engineer, USDA Forest Service, Engineering Staff, Washington Office. For consultation and assistance during preparation and review, USDA Forest Service Bridge Engineers, Steve Bunnell, Frank Muchmore, Sakee Poulakidas, Ron Schmidt, Merv Eriksson, and David Summy; Russ Moody and Alan Freas (retired) of the USDA Forest Service, Forest Products Laboratory; Dave Pollock of the National Forest Products Association; and Lorraine Krahn and James Wacker, former students at the University of Wisconsin at Madison. In addition, special thanks to Mary Jane Baggett and Jim Anderson for editorial consultation, JoAnn Benisch for graphics preparation and layout, and Stephen Schmieding and James Vargo for photographic support. iii iv CONTENTS CHAPTER 1 TIMBER AS A BRIDGE MATERIAL 1.1 Introduction .............................................................................. l- 1 1.2 Historical Development of Timber Bridges ............................. l-2 Prehistory Through the Middle Ages ....................................... l-3 Middle Ages Through the 18th Century ................................... l-5 19th Century ............................................................................. l-7 20th Century ............................................................................. l- 17 1.3 The Future of Timber as a Bridge Material .............................. l- 17 1.4 Selected References .................................................................. l-20 CHAPTER 2 TYPES OF TIMBER BRIDGES 2.1 Introduction ............................................................................ 2- 1 2.2 Beam Superstructures ............................................................... 2-2 Log Beams ................................................................................ 2-2 Sawn Lumber Beams ................................................................ 2-3 Glued-Laminated Timber Beams ............................................. 2- 5 Laminated Veneer Lumber Beams ........................................... 2- 6 2.3 Longitudinal Deck Superstructures .......................................... 2- 8 2.4 Trusses...................................................................................... 2- 10 2.5 Trestles ...................................................................................... 2- 12 2.6 Glulam Deck Arches ................................................................ 2- 13 2.7 Suspension Bridges ................................................................... 2- 15 2.8 Decks ........................................................................................ 2- 17 Sawn Lumber Planks ................................................................ 2- 17 Nail-Laminated Lumber ........................................................... 2- 18 Glued-Laminated Timber ......................................................... 2- 20 Composite Timber-Concrete .................................................... 2- 20 2.9 Stress-Laminated Timber ......................................................... 2- 22 2.10 Timber Substructures ............................................................... 2- 25 Abutments ............................................................................... 2- 25 Bents ........................................................................................ 2-25 2.11 Selected References ................................................................. 2- 28 v CHAPTER 3 PROPERTIES OF WOOD AND STRUCTURAL WOOD PRODUCTS 3.1 Introduction .............................................................................. 3- 1 3.2 Structure of Wood .................................................................... 3-1 Microstructure . .. 3-2 Macrostructure .......................................................................... 3-2 3.3 Physical Properties of Wood .................................................... 3-5 Directional Properties ............................................................... 3-6 Moisture Content ...................................................................... 3-6 Dimensional Stability ............................................................... 3-8 Density ...................................................................................... 3-11 Specific Gravity ........................................................................ 3-12 Thermal Expansion ................................................................... 3-12 Coefficients of Friction ............................................................. 3-13 Electrical Conductivity ............................................................. 3-13 Pyrolytic Properties .................................................................. 3-14 Natural Durability ..................................................................... 3-15 Chemical Resistance ................................................................. 3-16 3.4 Mechanical Properties .............................................................. 3-17 Elastic Properties ...................................................................... 3-17 Modulus of Elasticity.......................................................... 3-18 Shear Modulus .................................................................... 3-18 Poisson’s Ratio ................................................................... 3-18 Strength Properties . 3-18 Compression . 3-19 Tension . 3-20 Shear . 3-21 Bending . 3-22 Torsion . 3-22 Shock Resistance . 3-23 3.5 Factors Affecting the Strength and Other Properties of Wood . .. 3-23 Anatomical Factors . 3-23 Specific Gravity .................................................................. 3-23 Slope of Grain ..................................................................... 3-24 Knots ................................................................................... 3-24 Abnormal Wood ................................................................. 3-25 vi Compression Failures ........................................................ 3-27 Shake and Pitch Pockets ..................................................... 3-28 Environmental Factors .............................................................. 3-29 Moisture Content ................................................................ 3-29 Temperature ........................................................................ 3-30 Decay and Insect Damage .................................................. 3-30 Ultraviolet Degradation ...................................................... 3-31 Service-Factors ......................................................................... 3-31 Duration of Load ................................................................ 3-31 Creep ................................................................................... 3-32 Fatigue ................................................................................ 3-32 Treatment Factors ............................................................... 3-33 3.6 Properties of Sawn Lumber ...................................................... 3-33 Product Standards ..................................................................... 3-34 Lumber Manufacture ................................................................ 3-35 Lumber Species .................................................................. 3-35 Lumber Sizes ...................................................................... 3-36 Lumber Grading ....................................................................... 3-41 Visual Stress Grading ......................................................... 3-42 Mechanical Stress Grading ................................................. 3-46 Quality Control and Marking ................................................... 3-47 Material Specifications ............................................................. 3-48 3.7 Properties of Glued-Laminated Timber (Glulam) ................... .3-49 Product Standards ..................................................................... 3-50 Manufacturing Criteria for Glulam ........................................... 3-51 Standard Glulam Sizes ........................................................ 3-52 Adhesives ............................................................................ 3-53 Joints . .. 3-54 Appearance . 3-55 Grades of Glulam . 3-55 Bending Combinations . 3-56 Axial Combinations . 3-57 Quality Control and Marking . 3-57 Material Specifications . ....... 3-58 3.8 Selected References . 3-60 vii CHAPTER 4 PRESERVATION AND PROTECTION OF TIMBER BRIDGES 4.1 Introduction .............................................................................
Load more

Recommended publications
  • Timber Bridge History Booklet for Web.Qxp
    Printed on Member & recycled Supporter paper TimberTimber TrestleTrestle BridgesBridges inin Alaska Railroad Corporation P.O. Box 107500 • Anchorage, Alaska 99510-7500 (907) 265-2300 • Reservations • (907) 265-2494 AlaskaAlaska RailroadRailroad TTY/TDD • (907) 265-2620 www.AlaskaRailroad.com This History booklet is History also available online by visiting AlaskaRailroad.com Publication Table of Contents “The key to unlocking Alaska is a system of railroads.” — President Woodrow Wilson (1914) The Alaska Railroad at a Glance . 3 Alaska Railroad Historical Overview. 5 Early Development & Operations. 5 Revitalization & World War II . 6 Rehabilitation & Early Cold War . 7 Recent History . 7 About Timber Trestle Bridges . 8 History of Timber Trestle Bridges . 10 in the United States History of Timber Trestle Bridges . 13 on the Alaska Railroad Bridge under constructon at MP 54. (ARRC photo archive) Status of Timber Trestle Bridges . 18 on the Alaska Railroad Historical Significance of Alaska . … progress was immediately hindered 20 Railroad Timber Trestle Bridges by numerous water crossings and abundant muskeg. Representative ARR Timber Bridges . 20 Because a trestle was the easiest and cheapest way to negotiate these barriers, a great many of them were erected, Publication Credits . 22 only to be later replaced or Research Acknowledgements . 22 filled and then forgotten. — Alaska Engineering Commission (1915) Bibliography of References . 22 Cover photo: A train leaves Anchorage, crossing Ship Creek Bridge in 1922. (ARRC photo archive) 01 The Alaska Railroad at a Glance early a century ago, President Woodrow Wilson charged the Alaskan Engineering Commission with building a railroad connecting a southern ice-free harbor to the territory’s interior in order to open this vast area to commerce.
    [Show full text]
  • Truss Deflection
    Truss Deflection Truss deflection may be something you do not give much thought to when designing trusses. Unfortunately, meeting the code permitted deflection ratio does not always guarantee satisfactory performance. Regardless of what the codes say, most people regard large levels of deflection as a sign of structural deficiency. Paying attention to deflection may be the key to whether your customer is satisfied with you as a supplier and continues to buy your products. Deflection of a truss is generally based on the amount of vertical movement from its original position due to the loads applied to the members. The amount of deflection depends on the span and stiffness of the members, and the magnitude of the loads applied. Codes provide the maximum allowable deflection limits for floor and roof trusses, which is based solely on the truss span. Generally, for roof trusses, the deflection in inches due to live load cannot exceed the span in inches divided by 240 (L/240) and due to total load L/180. For floor trusses, the deflection in inches due to live load cannot exceed the span in inches divided by 360 (L/360) and due to total load L/240. To meet code deflection criteria, a 40-foot span roof truss could have live load deflection 2 inches, which does not ensure satisfactory performance. MiTek engineers recommend using the deflection limits listed below. Page 1 of 5 10 /12 /20 20 Truss Deflection Roof Trusses should use the following settings: In MiTek 20/20 Engineering go to Setup – Job – Design Info – Deflection: In Structure with Truss Design go to File – Setup – Job Properties - Job Settings – Design – Building Code Settings: Please note the settings for cantilever and overhang are half that of the main span.
    [Show full text]
  • Section 061053 - Miscellaneous Rough Carpentry
    SECTION 061053 - MISCELLANEOUS ROUGH CARPENTRY PART 1 - GENERAL 1.1 RELATED DOCUMENTS A. Drawings and general provisions of the Contract, including General and Supplementary Conditions and Division 01 Specification Sections, apply to this Section. 1.2 SUMMARY A. This Section includes the following: 1. Wood framing, blocking, and nailers 2. Wood battens, shims, and furring (for wall panel attachment). 3. Plywood sheathing for miscellaneous structures and replacement of deteriorated roof sheathing. B. Related Sections include the following: 1. Section 075216 "SBS Modified Bituminous Membrane Roofing" for adhesively applied 2-ply, SBS bituminous membrane roofing, with self-adhered base ply sheet. 2. Section 076200 "Sheet Metal Flashing and Trim" for installing sheet metal flashing and trim integral with roofing. 1.3 DEFINITIONS A. Dimension Lumber: Lumber of 2-inches nominal or greater but less than 5-inches nominal in least dimension. B. Lumber grading agencies, and the abbreviations used to reference them, include the following: 1. NLGA: National Lumber Grades Authority. 2. WCLIB: West Coast Lumber Inspection Bureau. 3. WWPA: Western Wood Products Association. 1.4 QUALITY ASSURANCE A. Testing Agency Qualifications: For testing agency providing classification marking for fire- retardant treated material, an inspection agency acceptable to authorities having jurisdiction that periodically performs inspections to verify that the material bearing the classification marking is representative of the material tested. PRSD – Thompson Elementary School Roof Replacement 061053 – MISCELLANEOUS ROUGH CARPENTRY July, 2012 Page 1 of 7 B. Forest Certification: For the following wood products, provide materials produced from wood obtained from forests certified by an FSC-accredited certification body to comply with FSC 1.2, "Principles and Criteria": 1.
    [Show full text]
  • The Development of Forest-Based Biorefineries: Implications for Market Behavior and Policy
    The Development of Forest-based Biorefineries: Implications for Market Behavior and Policy Patrik Söderholm and Robert Lundmark Abstract and the use of biomass is expected to constitute a major In a forest-based biorefinery, the entire potential of share of the future total use of renewable energy sources forest raw materials and byproducts may be used to pro- in Europe (European Commission 1997, 2006). Essential duce a diverse set of products, including transport fuels, components of national energy policies in Europe, there- chemicals, and pulp and paper products. This paper ana- fore, include not only direct promotion of renewable ener- lyzes the general impact on forest raw material markets gy technologies (e.g., investment and R&D support), but following an increased diffusion of biorefineries and high- also carbon dioxide taxes and emissions trading in carbon lights a number of related public policy issues. The analy- dioxide allowances that discourage the use of fossil fuels. The transition from a fossil fuel-based to a carbon-free sis indicates that the character of forest raw material sup- energy system may have important consequences for the ply, in particular the distinction between main products use of raw materials in society, not the least in cases of and byproducts, will have a major influence on the func- agricultural and forest-based resources. Increases in the tioning and the organization of future forest products mar- relative prices of fossil fuels affect a large number of indus- kets. Moreover, the advent of new uses of forest-based bio- trial and end-use sectors of the economy.
    [Show full text]
  • Truss Terminology
    TRUSS TERMINOLOGY BEARING WIDTH The width dimension of the member OVERHANG The extension of the top chord beyond the providing support for the truss (usually 3 1/2” or 5 1/2”). heel joint. Bearing must occur at a truss joint location. PANEL The chord segment between two adjacent joints. CANTILEVER That structural portion of a truss which extends PANEL POINT The point of intersection of a chord with the beyond the support. The cantilever dimension is measured web or webs. from the outside face of the support to the heel joint. Note that the cantilever is different from the overhang. PEAK Highest point on a truss where the sloped top chords meet. CAMBER An upward vertical displacement built into a truss bottom chord to compensate for defl ection due to dead load. PLATE Either horizontal 2x member at the top of a stud wall offering bearing for trusses or a shortened form of connector CHORDS The outer members of a truss that defi ne the plate, depending on usage of the word. envelope or shape. PLUMB CUT Top chord cut to provide for vertical (plumb) TOP CHORD An inclined or horizontal member that establishes installation of fascia. the upper edge of a truss. This member is subjected to compressive and bending stresses. SCARF CUT For pitched trusses only – the sloping cut of upper portion of the bottom chord at the heel joint. BOTTOM CHORD The horizontal (and inclined, ie. scissor trusses) member defi ning the lower edge of a truss, carrying SLOPE (PITCH) The units of horizontal run, in one unit of ceiling loads where applicable.
    [Show full text]
  • The Lebanon Nh-Vt Micropolitan Statistical Area
    THE LEBANON NH-VT MICROPOLITAN STATISTICAL AREA A GEO-DEMOGRAPHIC REVIEW by Robert Haslach urban analysis Washington, DC and Robert Leland RCLELAND CONSULTING LLC for The City of Lebanon, NH (under purchase order no. 1229) March 25, 2006 The statements, findings, conclusions, and recommendations found in this study are those of the authors, and do not necessarily reflect the views of the Department of Planning or The City of Lebanon, NH. The Lebanon NH-VT Micropolitan Statistical Area: a descriptive report urban analysis-Washington, DC _____________________________________________________________________________March 25, 2006 TABLE OF CONTENTS 1. Executive Summary 3 2. Purpose and Scope 5 3. Introduction to Micropolitan Statistical Areas 6 4. Methodology, Sources and Data Collection 9 5. Geography of the Lebanon NH-VT Micropolitan Statistical Area 10 6. Population 13 7. Housing 21 8. Employment 32 9. Transportation 36 10. Public Institutions 39 11. Conclusions 42 12. Sources 46 13. Definitions 49 2 The Lebanon NH-VT Micropolitan Statistical Area: a descriptive report urban analysis-Washington, DC _____________________________________________________________________________March 25, 2006 1. EXECUTIVE SUMMARY The Lebanon NH-VT Micropolitan Statistical Area is a geo-demographic area. Responses to Census 2000 questions by the residents of New Hampshire and Vermont defined its boundaries. After analysis of those responses, the U.S. Office of Management and Budget (OMB) selected the towns that showed the greatest social and economic interdependence to define the extent of The Lebanon NH-VT Micropolitan Statistical Area. The OMB uses a Micropolitan Statistical Area to present local and regional data so that it reflects the actual behaviors of its residents. The Lebanon NH-VT Micropolitan Statistical Area is an economically integrated region of 25 contiguous towns that spans four counties in two states.
    [Show full text]
  • Laval University
    LAVAL UNIVERSITY FACULTY OF FORESTRY AND GEOMATICS Department of Wood and Forest Sciences Sponsored by the International Development Center (IDRC) Ottawa, Canada “The Hidden World that Feeds Us: the Living Soil” Seminars given at the International Institute for Trropical Agriculture (ITA) Univeristy of Ibadan, Nigeria at the International Centre of Research in Agroforestry (ICRAF) Nairobi, Kenya and at the Ukrainian Academy of Agricultural Sciences Kiev, Ukraine by Professor Gilles Lemieux Department of Wood and Forestry Science ORIGINAL FRENCH PUBLICATION Nº 59b http://forestgeomat.ffg.ulaval.ca/brf/ edited by Coordination Group on Ramial Wood Depatment of Wood and Forestry Science Québec G1K 7P4 QUÉBEC CANADA TABLE OF CONTENTS I. A brief history: the evolution of ecosystems and man’s anthropocentric behaviour 1 II. The importance of the forest in tropical climates 2 III. The basic composition of wood 3 1. Lignin and its derivatives and their role in doil dynamic 5 IV. Stem wood and ramial wood 6 1. Stem wood and its lignin 6 2. Ramial wood and its lignin 6 3. Agricultural and forestry trials using ramial wood 7 V. “Organic Matter”, one of the basic principles in agriculture 9 1. Some a posteriori thoughts 10 2. The rationale for chipping 10 3. More like a food than a fertilizer 11 4. The principles behind chipping 11 VI. Lignin 13 1.The nutrients question 14 2.The biological cycling of water in tropical climates 15 3.“Chemical” nutrients 15 4.Nitrogen 15 5.Phosphorus 16 VII. A tentative theory 17 1.Too much or too little water 17 2.The soil-structuring role of lignin 17 3.The role of trophic web 18 4.Living beyond the soil’s chemical constraints 18 5.The major cause of tropical soils degradation.
    [Show full text]
  • Timber Bridges in South America
    Timber Bridges in South America Carlito Calil Junior, Laboratory of Wood and Timber Structures, Sao Paulo University, Brazil Abstract Beam Superstructures Timber bridges in South America predate the 19th Longitudinal beams superstructures are the simplest century. This paper provides an introduction of the and most common timber bridge type and consist of a many types of timber bridges currently used in South deck system supported by a series of timber beams America. The five basic types used, which are, the between two or more supports. Bridge beams are longitudinal beam, frame, truss, arch and suspension constructed from logs and sawn lumber, single or superstructures, are presented. Research on new bridge composite elements. designs, using tropical and reforestation wood species, has been developed in the Laboratory of Wood and Log Beams Timber Structures, Sao Paulo University in Brazil, on The simplest type of timber bridge in South America is prestressed timber bridge and decks composed with the log beam. It is constructed by placing round logs two diagonal layers of sawn wood connected with alternately tip and butt sections. The span of log beam wood dowels over composed longitudinal beams. We is limited to sizes and truck loads. The clear span of 5 will construct the first prestressed timber bridge in to 12 meters are most common (Figure 1). South America in this year using Eucalyptus Citriodora specie. In order to support high truck loads, LaMEM developed a longitudinal beam with composite Keywords: timber, briges, South America, Brazil configuration of two logs alternately tip and butt sections and connected with split rings and bolts Introduction (Figure 2).
    [Show full text]
  • Field Testing and Structural Analysis of Burr Arch Covered Bridges in Pennsylvania
    Field Testing and Structural Analysis of Burr Arch Covered Bridges in Pennsylvania Douglas Rammer1, James Wacker2, Travis Hosteng3, Justin Dahlberg4 and Yaohua Deng5 ABSTRACT: The Federal Highway Administration sponsored a comprehensive research program on Historic Covered Timber Bridges in the USA. This national program's main purpose is to develop improved methods to preserve, rehabilitate, and restore timber bridge trusses that were developed during the early 1800s and, in many cases, are still in service today. One of the many ongoing research studies is aimed at establishing a procedure for safely and reliably load- rating historic covered bridges though physical testing and improved structural modelling. This paper focuses on recent field work and analysis of four Burr Arch through-truss-type covered bridges located in Lancaster County, Pennsylvania. An overview of field evaluation methods, loading testing, and structural modelling procedures are included along with a comparison of field measurements and structural model prediction of bridge behaviour. KEYWORDS: loading rating, structural analysis, covered bridges, historical landmark, burr arch 1 INTRODUCTION 123 established for historic covered bridges. Given the historic nature and unusual geometric features of these The Federal Highway Administration (FHWA), in structures, a procedure needs to be established detailing partnership with the USDA Forest Products Laboratory how to safely and reliably determine load ratings for and the National Park Service (NPS), sponsored a historic covered timber bridges through physical testing. comprehensive national research program on Historic Covered Timber Bridges in the USA. The main purpose Similarly, the complex behavior and unique details of is to develop improved methods to preserve, rehabilitate, covered bridges make structural modeling a daunting task and restore timber bridge trusses that were first developed for the typical bridge engineer.
    [Show full text]
  • UFGS 06 10 00 Rough Carpentry
    ************************************************************************** USACE / NAVFAC / AFCEC / NASA UFGS-06 10 00 (August 2016) Change 2 - 11/18 ------------------------------------ Preparing Activity: NAVFAC Superseding UFGS-06 10 00 (February 2012) UNIFIED FACILITIES GUIDE SPECIFICATIONS References are in agreement with UMRL dated July 2021 ************************************************************************** SECTION TABLE OF CONTENTS DIVISION 06 - WOOD, PLASTICS, AND COMPOSITES SECTION 06 10 00 ROUGH CARPENTRY 08/16, CHG 2: 11/18 PART 1 GENERAL 1.1 REFERENCES 1.2 SUBMITTALS 1.3 DELIVERY AND STORAGE 1.4 GRADING AND MARKING 1.4.1 Lumber 1.4.2 Structural Glued Laminated Timber 1.4.3 Plywood 1.4.4 Structural-Use and OSB Panels 1.4.5 Preservative-Treated Lumber and Plywood 1.4.6 Fire-Retardant Treated Lumber 1.4.7 Hardboard, Gypsum Board, and Fiberboard 1.4.8 Plastic Lumber 1.5 SIZES AND SURFACING 1.6 MOISTURE CONTENT 1.7 PRESERVATIVE TREATMENT 1.7.1 Existing Structures 1.7.2 New Construction 1.8 FIRE-RETARDANT TREATMENT 1.9 QUALITY ASSURANCE 1.9.1 Drawing Requirements 1.9.2 Data Required 1.9.3 Humidity Requirements 1.9.4 Plastic Lumber Performance 1.10 ENVIRONMENTAL REQUIREMENTS 1.11 CERTIFICATIONS 1.11.1 Certified Wood Grades 1.11.2 Certified Sustainably Harvested Wood 1.11.3 Indoor Air Quality Certifications 1.11.3.1 Adhesives and Sealants 1.11.3.2 Composite Wood, Wood Structural Panel and Agrifiber Products SECTION 06 10 00 Page 1 PART 2 PRODUCTS 2.1 MATERIALS 2.1.1 Virgin Lumber 2.1.2 Salvaged Lumber 2.1.3 Recovered Lumber
    [Show full text]
  • The Decomposition of Forest Products in Landfills
    International Biodeterioration & Biodegradation Vol. 39, No. 2–3 (1997) 145–158 Published by Elsevier Science Limited Printed in Great Britain PII:S0964-8305(96)00039-X 0964-8305/97 $17.00 + .00 ELSEVIER The Decomposition of Forest Products in Landfills J. A. Micales & K. E. Skog USDA Forest Service, Forest Products Laboratory, One Gifford Pinchot Drive, Madison, WI 53705, USA (Received 3 April 1996; revised version received 25 June 1996; accepted 22 July 1996) Large quantities of forest products are disposed of in landfills annually. The fate of this vast pool of carbon is important since carbon sequestration and the generation of landfill gases have important implications for global warming. Published estimates of methane yields were used to estimate the amount of carbon released into the atmosphere from landfilled forest products. These calculations suggest that maximally only 30%, of the carbon from paper and 0- 3% of the carbon from wood are ever emitted as landfill gas. The remaining carbon, approximately 28 Tg in 1993, remains in the landfill indefinitely. Some of this carbon may be removed during leachate treatment, but a large portion is permanently sequestered where its impact on global warming is negligible. The placement of forest products in landfills serves as a significant carbon sink, and its importance in the global carbon balance should not be overlooked. Published by Elsevier Science Limited INTRODUCTION warming? President Clinton’s Climatic Change Action Plan (Clinton & Gore, 1993) sets a US In 1993, the US Environmental Protection Agency objective of restraining carbon emission growth (EPA) (1994) estimated that 50 Tgl of paper and and increasing sequestration by a total of 100 Tg/ 18.6 Tg of wood were discarded in the United year by the year 2000.
    [Show full text]
  • A Look at Bridges: a Study of Types, Histories, and the Marriage of Engineering and Architecture Cody Chase Connecticut College
    Connecticut College Digital Commons @ Connecticut College Architectural Studies Integrative Projects Art History and Architectural Studies 2015 A Look at Bridges: A Study of Types, Histories, and the Marriage of Engineering and Architecture Cody Chase Connecticut College Follow this and additional works at: http://digitalcommons.conncoll.edu/archstudintproj Recommended Citation Chase, Cody, "A Look at Bridges: A Study of Types, Histories, and the Marriage of Engineering and Architecture" (2015). Architectural Studies Integrative Projects. Paper 73. http://digitalcommons.conncoll.edu/archstudintproj/73 This Article is brought to you for free and open access by the Art History and Architectural Studies at Digital Commons @ Connecticut College. It has been accepted for inclusion in Architectural Studies Integrative Projects by an authorized administrator of Digital Commons @ Connecticut College. For more information, please contact [email protected]. The views expressed in this paper are solely those of the author. CODY CHASE SENIOR INTEGRATIVE PROJECT: INDEPENDENT STUDY ARCHITECTURAL STUDIES CONNECTICUT COLLEGE 2015 A"LOOK"INTO"BRIDGES" A"Study"of"Types,"Histories,"and"the"Marriage"of" Engineering"and"Architecture" " Cody"Chase"‘15" Architectural"Studies"Major,"Art"History"Minor" Senior"IntegraHve"Project" " Why Bridges? Where to begin? TYPES OTHER • Arch • Glossary • Beam/Girder/Stringer • Materials • Truss • History of Failures • Suspension • Models • Cable-Stayed • Moveable Span What makes a bridge stand up? FORCES ***Compression:
    [Show full text]