DOCSLIB.ORG

Post-Tensioned Box Girder Design Manual

Total Page：16

File Type：pdf, Size：1020Kb

Download full-text PDF Read full-text
Post-Tensioned Box Girder Design Manual Post-Tensioned Box Girder Design Manual June 2016 This page intentionally left blank. 1. Report No. 2. Government Accession No. 3. Recipient’s Catalog No. FHWA-HIF-15-016 XXX XXX 4. Title and Subtitle 5. Report Date Post-Tensioned Box Girder Design Manual June 2016 Task 3: Post-Tensioned Box Girder Design Manual 6. Performing Organization Code XXX 7. Author(s) 8. Performing Organization Report No. Corven, John XXX 9. Performing Organization Name and Address 10. Work Unit No. Corven Engineering Inc., XXX 2864 Egret Lane Tallahassee, FL 32308 11. Contract or Grant No. DTFH61-11-H-00027 12. Sponsoring Agency Name and Address 13. Type of Report and Period Covered Federal Highway Administration XXX Office of Infrastructure – Bridges and Structures 1200 New Jersey Ave., SE Washington, DC 20590 14. Sponsoring Agency Code HIBS-10 15. Supplementary Notes Work funded by Cooperative Agreement “Advancing Steel and Concrete Bridge Technology to Improve Infrastructure Performance” between FHWA and Lehigh University. 16. Abstract This Manual contains information related to the analysis and design of cast-in-place concrete box girder bridges prestressed with post- tensioning tendons. The Manual is targeted at Federal, State and local transportation departments and private company personnel that may be involved in the analysis and design of this type of bridge. The Manual reviews features of the construction of cast-in-place concrete box girder bridges, material characteristics that impact design, fundamentals of prestressed concrete, and losses in prestressing force related to post-tensioned construction. Also presented in this Manual are approaches to the longitudinal and transverse analysis of the box girder superstructure. Both single-cell and multi-cell box girders are discussed. Design examples are presented in Appendices to this Manual. The document is part of the Federal Highway Administration’s national technology deployment program and may serve as a training manual. 17. Key Words 18. Distribution Statement Box girder, Cast-in-place, Multi-cell, Concrete, Top Slab, No restrictions. This document is available to the public Cantilever Wing, Web, Bottom Slab, Prestressing, Post- online and through the National Technical Information tensioning, Strand, Tendon, Duct, Anchorage, Losses, Friction, Wobble, Elastic Shortening, Creep, Shrinkage, Service, Springfield, VA 22161. Force, Eccentricity, Bending moment, Shear, Torsion, Joint flexibilities, Longitudinal analysis, Transverse analysis 9. Security Classif. (of this 20. Security Classif. (of this 21. No of Pages 22. Price report) page) 355 $XXX.XX Unclassified Unclassified SI* (MODERN METRIC) CONVERSION FACTORS APPROXIMATE CONVERSIONS TO SI UNITS Symbol When You Know Multiply By To Find Symbol LENGTH in inches 25.4 millimeters mm ft feet 0.305 meters m yd yards 0.914 meters m mi miles 1.61 kilometers km AREA in2 square inches 645.2 square millimeters mm2 ft2 square feet 0.093 square meters m2 yd2 square yard 0.836 square meters m2 ac acres 0.405 hectares ha mi2 square miles 2.59 square kilometers km2 VOLUME fl oz fluid ounces 29.57 milliliters mL gal gallons 3.785 liters L ft3 cubic feet 0.028 cubic meters m3 yd3 cubic yards 0.765 cubic meters m3 NOTE: volumes greater than 1000 L shall be shown in m3 MASS oz ounces 28.35 grams g lb pounds 0.454 kilograms kg T short tons (2000 lb) 0.907 megagrams (or "metric ton") Mg (or "t") TEMPERATURE (exact degrees) oF Fahrenheit 5 (F-32)/9 Celsius oC or (F-32)/1.8 ILLUMINATION fc foot-candles 10.76 lux lx fl foot-Lamberts 3.426 candela/m2 cd/m2 FORCE and PRESSURE or STRESS lbf poundforce 4.45 newtons N lbf/in2 poundforce per square inch 6.89 kilopascals kPa APPROXIMATE CONVERSIONS FROM SI UNITS Symbol When You Know Multiply By To Find Symbol LENGTH mm millimeters 0.039 inches in m meters 3.28 feet ft m meters 1.09 yards yd km kilometers 0.621 miles mi AREA mm2 square millimeters 0.0016 square inches in2 m2 square meters 10.764 square feet ft2 m2 square meters 1.195 square yards yd2 ha hectares 2.47 acres ac km2 square kilometers 0.386 square miles mi2 VOLUME mL milliliters 0.034 fluid ounces fl oz L liters 0.264 gallons gal m3 cubic meters 35.314 cubic feet ft3 m3 cubic meters 1.307 cubic yards yd3 MASS g grams 0.035 ounces oz kg kilograms 2.202 pounds lb Mg (or "t") megagrams (or "metric ton") 1.103 short tons (2000 lb) T TEMPERATURE (exact degrees) oC Celsius 1.8C+32 Fahrenheit oF ILLUMINATION lx lux 0.0929 foot-candles fc cd/m2 candela/m2 0.2919 foot-Lamberts fl FORCE and PRESSURE or STRESS N newtons 0.225 poundforce lbf kPa kilopascals 0.145 poundforce per square inch lbf/in2 *SI is the symbol for the International System of Units. Appropriate rounding should be made to comply with Section 4 of ASTM E380. (Revised March 2003) Visit http://www.fhwa.dot.gov/publications/convtabl.cfm for a 508 compliant version of this table. This page intentionally left blank. Post-Tensioned Box Girder Design Manual June 2016 Preface This Manual contains information related to the analysis and design of cast-in-place concrete box girder bridges prestressed with post-tensioning tendons. The Manual is targeted at Federal, State and local transportation departments and private company personnel that may be involved in the analysis and design of this type of bridge. The Manual reviews features of the construction of cast-in-place concrete box girder bridges, material characteristics that impact design, fundamentals of prestressed concrete, and losses in prestressing force related to post- tensioned construction. Also presented in this Manual are approaches to the longitudinal and transverse analysis of the box girder superstructure. Both single-cell and multi-cell box girders are discussed. Design examples are presented in Appendices to this Manual. The document is part of the Federal Highway Administration’s national technology deployment program and may serve as a training manual. Preface i Post-Tensioned Box Girder Design Manual June 2016 This page intentionally left blank. ii Post-Tensioned Box Girder Design Manual June 2016 Table of Contents Chapter 1 – Introduction ...........................................................................................................1 1.1 Historical Overview .............................................................................................................1 1.2 Typical Superstructure Cross Sections ............................................................................... 2 1.3 Longitudinal Post-Tensioning Layouts ................................................................................ 3 1.4 Loss of Prestressing Force ................................................................................................. 6 1.5 Post-Tensioning System Hardware .................................................................................... 6 1.5.1 Basic Bearing Plates ....................................................................................... 6 1.5.2 Special Bearing Plates or Anchorage Devices ................................................. 7 1.5.3 Wedge Plates ..................................................................................................8 1.5.4 Wedges and Strand-Wedge Connection .......................................................... 8 1.5.5 Permanent Grout Caps .................................................................................... 8 1.5.6 Ducts ...............................................................................................................9 1.5.6.1 Duct Size...........................................................................................9 1.5.6.2 Corrugated Steel Duct ....................................................................... 9 1.5.6.3 Corrugated Plastic ........................................................................... 10 1.5.6.4 Plastic Fittings and Connections for Internal Tendons ..................... 11 1.5.6.5 Grout Inlets, Outlets, Valves and Plugs ........................................... 11 1.5.7 Post-Tensioning Bars Anchor Systems .......................................................... 11 1.6 Overview of Construction ................................................................................................. 12 1.6.1 Falsework ...................................................................................................... 12 1.6.2 Superstructure Formwork .............................................................................. 13 1.6.3 Reinforcing and Post-Tensioning Hardware Placement ................................. 15 1.6.4 Placing and Consolidating Superstructure Concrete ...................................... 15 1.6.5 Superstructure Curing.................................................................................... 16 1.6.6 Post-Tensioning Operations .......................................................................... 17 1.6.7 Tendon Grouting and Anchor Protection ........................................................ 19 Chapter 2 – Materials .............................................................................................................. 20 2.1 Concrete ..........................................................................................................................20 2.1.1 Compressive Strength ................................................................................... 20 2.1.2 Development of Compressive Strength with Time ......................................... 21 2.1.3 Tensile Strength ...........................................................................................
Load more

Recommended publications
  • Evaluation of a High Performance Concrete Box Girder Bridge
    Evaluation of a High Performance Concrete Box Girder Bridge Andreas Greuel T. Michael Baseheart, Ph. D. Graduate Research Assistant Associate Professor of Civil University of Cincinnati Engineering Cincinnati, Ohio University of Cincinnati Cincinnati, Ohio Bradley T. Rogers Engineer LJB, Inc. As part of the FHWA (Federal Highway Admin- Dayton, Ohio istration) High Performance Concrete Bridge Program, two full-scale truckload tests of Bridge GUE-22-6.57 were carried out. The main ob- jectives of these tests were to investigate the static and dynamic response of the high perfor- Richard A. Miller, Ph. D. mance concrete (HPC) structure. A secondary Associate Professor of Civil Engineering objective was to investigate the load transfer University of Cincinnati between the box girders through experimental Cincinnati, Ohio middepth shear keys. The structure was loaded using standard Ohio Department of Transporta- tion (ODOT) dump trucks. A model test of the bridge was conducted as well. It was found that the bridge behavior is well predicted using sim- ple models. The bridge behaves as a single unit and all girders share the load almost equally. Bahram M. Shahrooz, Ph. D. The dynamic behavior of the bridge is typical Associate Professor of Civil for comparable structures. Engineering University of Cincinnati Cincinnati, Ohio 60 PCI JOURNAL he use of high performance con- located on US Route 22, a heavily in that the Ohio box girder has only a crete (HPC) can lead to more traveled two-lane highway near Cam- 5 in. (127 mm ) thick bottom flange Teconomical bridge designs be- bridge, Ohio. rather than the 5.5 in.
    [Show full text]
  • Review on Applicability of Box Girder for Balanced Cantilever Bridge Sneha Redkar1, Prof
    International Research Journal of Engineering and Technology (IRJET) e-ISSN: 2395 -0056 Volume: 03 Issue: 05 | May-2016 www.irjet.net p-ISSN: 2395-0072 Review on applicability of Box Girder for Balanced Cantilever Bridge Sneha Redkar1, Prof. P. J. Salunke2 1Student, Dept. of Civil Engineering, MGMCET, Maharashtra, India 2Head, Assistant Professor, Dept. of Civil Engineering, MGMCET, Maharashtra, India ---------------------------------------------------------------------***--------------------------------------------------------------------- Abstract - This paper gives a brief introduction to the 1874. Use of steel led to the development of cantilever cantilever bridges and its evolution. Further in cantilever bridges. The world’s longest span cantilever bridge was built bridges it focuses on system and construction of balanced in 1917 at Quebec over St. Lawrence River with main span of cantilever bridges. The superstructure forms the dynamic 549 m. India can boast of one such long bridge, the Howrah element as a load carrying capacity. As box girders are widely bridge, over river Hooghly with main span of 457 m which is used in forming the superstructure of balanced cantilever fourth largest of its kind. bridges, its advantages are discussed and a detailed review is carried out. Concrete cantilever construction was first introduced in Europe in early 1950’s and it has since been broadly used in design and construction of several bridges. Unlike various Key Words: Bridge, Balanced Cantilever, Superstructure, bridges built in Germany using cast-in-situ method, Box Girder, Pre-stressing cantilever construction in France took a different direction, emphasizing the use of precast segments. The various advantages of precast segments over cast-in-situ are: 1. INTRODUCTION i. Precast segment construction method is a faster method compared to cast-in-situ construction method.
    [Show full text]
  • Bridges Key Stage 2 Thematic Unit
    Bridges Key Stage 2 Thematic Unit Supporting the Areas of Learning and STEM Contents Section 1 Activity 1 Planning Together 3 Do We Need Activity 2 Do We Really Need Bridges? 4 Bridges? Activity 3 Bridges in the Locality 6 Activity 4 Decision Making: Cantilever City 8 Section 2 Activity 5 Bridge Fact-File 13 Let’s Investigate Activity 6 Classifying Bridges 14 Bridges! Activity 7 Forces: Tension and Compression 16 Activity 8 How Can Shapes Make a Bridge Strong? 18 Section 3 Activity 9 Construction Time! 23 Working with Activity 10 Who Builds Bridges? 25 Bridges Activity 11 Gustave Eiffel: A Famous Engineer 26 Activity 12 Building a Bridge and Thinking Like an Engineer 28 Resources 33 Suggested Additional Resources 60 This Thematic Unit is for teachers of Key Stage 2 children. Schools can decide which year group will use this unit and it should be presented in a manner relevant to the age, ability and interests of the pupils. This Thematic Units sets out a range of teaching and learning activities to support teachers in delivering the objectives of the Northern Ireland Curriculum. It also supports the STEM initiative. Acknowledgement CCEA would like to thank The Institution of Civil Engineers Northern Ireland (ICE NI) for their advice and guidance in the writing of this book. Cover image © Thinkstock Do We Need Bridges? Planning together for the theme. Discovering the reasons for having, and the impact of not having, bridges. Writing a newspaper report about the impact of a missing bridge. Researching bridges in the locality. Grouping and classifying bridges.
    [Show full text]
  • Bridges for Planes, Trains, but Not Automobiles by David A
    bridges for Planes, Trains, buT noT auTomobiles By David A. Burrows, P.E., LEED AP BD+C ® British Airways 747 crossing beneath the Taxiway “R” bridge, June, 2012. Courtesy of City of Phoenix Aviation Department. Copyright s described in the August edition of STRUCTURE® maga- zine, Phoenix Sky Harbor International Airport opened the first stage of their automated transit system, PHX Sky Train™, on April 8, 2013. Thousands of passengers have already boarded the Sky Train and experienced the comfortable five A th minute ride from the 44 Street Station through the East Economy Lot Station, over Taxiway “R” (more than 100 feet above Sky Harbor Blvd.), ending at Terminal 4. The next phase, known as Stage 1A, is currently under con- struction and continues Sky Train’s route from Terminal 4 to Terminal 3. Scheduled to be open in early 2015, Stagemagazine 1A, similar to the Stage 1 construction,S faces theT task ofR crossing U an active C T U R E taxiway. Unlike the first Stage’s crossing above Taxiway “R”, the current phase of construction crosses beneath Taxiways “S” and “T”. Both Stages’ taxiway crossings presented several design and construction challenges. A US Airways jet passes beneath the Taxiway R crossing with the PHX Sky Train overhead. Courtesy of City of Phoenix Aviation Department. The World’s First In addition to the challenging geometry was the schedule constraint On Oct. 10, 2010, a celebration to mark the re-opening of Taxiway for constructing the bridge. Because the construction required the “R” was held by the City of Phoenix with members of the City’s taxiway to be closed, a limited shutdown period of six months was Aviation Department, designers, contractors and media watching possible due to airport operations.
    [Show full text]
  • Lecture Notes on Structural Analysis - I
    www.jntuhweb.com JNTUH WEB LECTURE NOTES ON STRUCTURAL ANALYSIS - I Department of Civil Engineering Skyupsmedia JNTUH WEB www.jntuhweb.com JNTUH WEB CONTENTS CHAPTER 1 Analysis of Perfect Frames Types of frame - Perfect, Imperfect and Redundant pin jointed frames Analysis of determinate pin jointed frames using method of joint for vertical loads, horizontal loads and inclined loads method of sections for vertical loads, horizontal loads and inclined loads tension co-effective method for vertical loads, horizontal loads and inclined loads CHAPTER 2 Energy Theorem - Three Hinged Arches Introduction Strain energy in linear elastic system Expression of strain energy due axial load, bending moment and shear forces Castiglione’s first theorem – Unit Load Method Deflections of simple beams and pin - jointed plain trusses Deflections of statically determinate bent frames. Introduction Types of arches Comparison between three hinged arches and two hinged arches Linear Arch Eddy's theorem Analysis three hinged arches Normal Thrust and radial shear in an arch Geometrical properties of parabolic and circular arch Three Hinged circular arch at Different levels Absolute maximum bending moment diagram for a three hinged arch CHAPTERSkyupsmedia 3 Propped Cantilever and Fixed beams Analysis of Propped Cantilever and Fixed beams including the beams with varying moments of inertia subjected to uniformly distributed load central point load eccentric point load number of point loads uniformly varying load couple and combination of loads JNTUH WEB
    [Show full text]
  • Steel Bridge Design Handbook Vol. 13
    U.S. Department of Transportation Federal Highway Administration Steel Bridge Design Handbook Bracing System Design Publication No. FHWA-HIF-16-002 - Vol. 13 December 2015 FOREWORD This handbook covers a full range of topics and design examples intended to provide bridge engineers with the information needed to make knowledgeable decisions regarding the selection, design, fabrication, and construction of steel bridges. Upon completion of the latest update, the handbook is based on the Seventh Edition of the AASHTO LRFD Bridge Design Specifications. The hard and competent work of the National Steel Bridge Alliance (NSBA) and prime consultant, HDR, Inc., and their sub-consultants, in producing and maintaining this handbook is gratefully acknowledged. The topics and design examples of the handbook are published separately for ease of use, and available for free download at the NSBA and FHWA websites: http://www.steelbridges.org, and http://www.fhwa.dot.gov/bridge, respectively. The contributions and constructive review comments received during the preparation of the handbook from many bridge engineering processionals across the country are very much appreciated. In particular, I would like to recognize the contributions of Bryan Kulesza with ArcelorMittal, Jeff Carlson with NSBA, Shane Beabes with AECOM, Rob Connor with Purdue University, Ryan Wisch with DeLong’s, Inc., Bob Cisneros with High Steel Structures, Inc., Mike Culmo with CME Associates, Inc., Mike Grubb with M.A. Grubb & Associates, LLC, Don White with Georgia Institute of Technology, Jamie Farris with Texas Department of Transportation, and Bill McEleney with NSBA. Joseph L. Hartmann, PhD, P.E. Director, Office of Bridges and Structures Notice This document is disseminated under the sponsorship of the U.S.
    [Show full text]
  • Steel Bridge Design Handbook
    U.S. Department of Transportation Federal Highway Administration Steel Bridge Design Handbook Design Example 4: Three-Span Continuous Straight Composite Steel Tub Girder Bridge Publication No. FHWA-HIF-16-002 - Vol. 24 December 2015 FOREWORD This handbook covers a full range of topics and design examples intended to provide bridge engineers with the information needed to make knowledgeable decisions regarding the selection, design, fabrication, and construction of steel bridges. Upon completion of the latest update, the handbook is based on the Seventh Edition of the AASHTO LRFD Bridge Design Specifications. The hard and competent work of the National Steel Bridge Alliance (NSBA) and prime consultant, HDR, Inc., and their sub-consultants, in producing and maintaining this handbook is gratefully acknowledged. The topics and design examples of the handbook are published separately for ease of use, and available for free download at the NSBA and FHWA websites: http://www.steelbridges.org, and http://www.fhwa.dot.gov/bridge, respectively. The contributions and constructive review comments received during the preparation of the handbook from many bridge engineering processionals across the country are very much appreciated. In particular, I would like to recognize the contributions of Bryan Kulesza with ArcelorMittal, Jeff Carlson with NSBA, Shane Beabes with AECOM, Rob Connor with Purdue University, Ryan Wisch with DeLong’s, Inc., Bob Cisneros with High Steel Structures, Inc., Mike Culmo with CME Associates, Inc., Mike Grubb with M.A. Grubb & Associates, LLC, Don White with Georgia Institute of Technology, Jamie Farris with Texas Department of Transportation, and Bill McEleney with NSBA. Joseph L. Hartmann, PhD, P.E.
    [Show full text]
  • Single-Span Cast-In-Place Post-Tensioned Concrete
    LRFD Example 1 1-Span CIPPTCBGB 1-Span Cast-in-Place Cast-in-place post-tensioned concrete box girder bridge. The bridge has a 160 Post-Tensioned feet span with a 15 degree skew. Standard ADOT 32-inch f-shape barriers will Concrete Box Girder be used resulting in a bridge configuration of 1’-5” barrier, 12’-0” outside [CIPPTCBGB] shoulder, two 12’-0” lanes, a 6’-0” inside shoulder and a 1’-5” barrier. The Bridge Example overall out-to-out width of the bridge is 44’-10”. A plan view and typical section of the bridge are shown in Figures 1 and 2. The following legend is used for the references shown in the left-hand column: [2.2.2] AASHTO LRFD Specification Article Number [2.2.2-1] AASHTOLRFD Specification Table or Equation Number [C2.2.2] AASHTO LRFD Specification Commentary [A2.2.2] AASHTO LRFD Specification Appendix [BDG] ADOT LRFD Bridge Design Guidelines Bridge Geometry Bridge length 160.00 ft Bridge width 44.83 ft Roadway width 42.00 ft Superstructure depth 7.50 ft Web spacing 9.25 ft Web thickness 12.00 in Top slab thickness 8.50 in Bottom slab thickness 6.00 in Deck overhang 3.33 ft Minimum Requirements The minimum span to depth ratio for a single span bridge should be taken as 0.045 resulting in a minimum depth of 7.20 feet. Use 7’-6” [Table 2.5.2.6.3-1] The minimum top slab thickness shall be as shown in the LRFD Bridge Design Guidelines. For a centerline spacing of 9.25 feet, the effective length is 8.25 feet resulting in a minimum thickness of 8.50 inches.
    [Show full text]
  • Recent Technology of Prestressed Concrete Bridges in Japan
    IABSE-JSCE Joint Conference on Advances in Bridge Engineering-II, August 8-10, 2010, Dhaka, Bangladesh. ISBN: 978-984-33-1893-0 Amin, Okui, Bhuiyan (eds.) www.iabse-bd.org Recent technology of prestressed concrete bridges in Japan Hiroshi Mutsuyoshi & Nguyen Duc Hai Department of Civil and Environmental Engineering, Saitama University, Saitama 338-8570, Japan Akio Kasuga Sumitomo Mitsui Construction Co., Ltd., Tokyo 104-0051, Japan ABSTRACT: Prestressed concrete (PC) technology is being used all over the world in the construction of a wide range of bridge structures. However, many PC bridges have been deteriorating even before the end of their design service-life due to corrosion and other environmental effects. In view of this, a number of innova- tive technologies have been developed in Japan to increase not only the structural performance of PC bridges, but also their long-term durability. These include the development of novel structural systems and the ad- vancement in construction materials. This paper presents an overview of such innovative technologies on PC bridges on their development and applications in actual construction projects. Some noteworthy structures, which represent the state-of-the-art technologies in the construction of PC bridges in Japan, are also pre- sented. 1 INTRODUCTION Prestressed concrete (PC) technology is widely being used all over the world in construction of wide range of structures, particularly bridge structures. In Japan, the application of prestressed concrete was first introduced in the 1950s, and since then, the construction of PC bridges has grown dramatically. The increased interest in the construction of PC bridges can be attributed to the fact that the initial and life-cycle cost of PC bridges, including repair and maintenance, are much lower than those of steel bridges.
    [Show full text]
  • Over Jones Falls. This Bridge Was Originally No
    The same eastbound movement from Rockland crosses Bridge 1.19 (miles west of Hollins) over Jones Falls. This bridge was originally no. 1 on the Green Spring Branch in the Northern Central numbering scheme. PHOTO BY MARTIN K VAN HORN, MARCH 1961 /COLLECTION OF ROBERT L. WILLIAMS. On October 21, 1959, the Interstate Commerce maximum extent. William Gill, later involved in the Commission gave notice in its Finance Docket No. streetcar museum at Lake Roland, worked on the 20678 that the Green Spring track west of Rockland scrapping of the upper branch and said his boss kept would be abandoned on December 18, 1959. This did saying; "Where's all the steel?" Another Baltimore not really affect any operations on the Green Spring railfan, Mark Topper, worked for Phillips on the Branch. Infrequently, a locomotive and a boxcar would removal of the bridge over Park Heights Avenue as a continue to make the trip from Hollins to the Rockland teenager for a summer job. By the autumn of 1960, Team Track and return. the track through the valley was just a sad but fond No train was dispatched to pull the rail from the memory. Green Spring Valley. The steel was sold in place to the The operation between Hollins and Rockland con- scrapper, the Phillips Construction Company of tinued for another 11/2 years and then just faded away. Timonium, and their crews worked from trucks on ad- So far as is known, no formal abandonment procedure jacent roads. Apparently, Phillips based their bid for was carried out, and no permission to abandon was the job on old charts that showed the trackage at its ' obtained.
    [Show full text]
  • Polydron-Bridges-Work-Cards.Pdf
    Getting Started You will need: A Polydron Bridges Set ❑ This activity introduces you to the parts in the set and explains what each of them does. A variety of traditional Polydron and Frameworks pieces are used in each of the activities. However, they are coloured to produce more realistic effects. For example, the traditional squares are black and used to represent the road on the bridge deck. Plinth ❑ On the right you can see the plinth or bridge base. All of the bridges use one or two of these. They give each bridge a firm base and allow special parts to be connected easily. Notice the two holes in the top on the plinth. These holes are for long struts. These can be seen in place below. ❑ The second picture shows the plinth with two right-angled triangles and a rectangle connected. All three of these parts clip into the plinth. Struts ❑ There are three different lengths of strut in the set. There are 80mm short struts that are used with the pulleys with lugs to carry cables. These are shown on the left. The lugs fit into long struts. On the Drawbridge 110mm short struts are used with ordinary pulleys and a winding handle. ❑ Long struts are also used to support the cable assembly of the Suspension Bridge and the Cable Stay Bridge. This idea can be seen in the picture on the right. ❑ Long struts are also used to connect the two sections of the Drawbridge. ® ©Bob Ansell Special Rectangles ❑ Special rectangles can be used in a variety of ways.
    [Show full text]
  • Glulam Timber Bridges for Local Roads Zachary Charles Carnahan South Dakota State University
    South Dakota State University Open PRAIRIE: Open Public Research Access Institutional Repository and Information Exchange Theses and Dissertations 2017 Glulam Timber Bridges for Local Roads Zachary Charles Carnahan South Dakota State University Follow this and additional works at: http://openprairie.sdstate.edu/etd Part of the Civil and Environmental Engineering Commons Recommended Citation Carnahan, Zachary Charles, "Glulam Timber Bridges for Local Roads" (2017). Theses and Dissertations. 1173. http://openprairie.sdstate.edu/etd/1173 This Thesis - Open Access is brought to you for free and open access by Open PRAIRIE: Open Public Research Access Institutional Repository and Information Exchange. It has been accepted for inclusion in Theses and Dissertations by an authorized administrator of Open PRAIRIE: Open Public Research Access Institutional Repository and Information Exchange. For more information, please contact [email protected]. GLULAM TIMBER BRIDGES FOR LOCAL ROADS BY ZACHARY CHARLES CARNAHAN A thesis in partial fulfillment of the requirements for the Master of Science Major in Civil Engineering South Dakota State University 2017 iii DISCLAIMER The contents of this report, funded in part through grant(s) from the Federal Highway Administration, reflect the views of the authors who are responsible for the facts and accuracy of the data presented herein. The contents do not necessarily reflect the official views or policies of the South Dakota Department of Transportation, the State Transportation Commission, or the Federal Highway Administration. This report does not constitute a standard, specification, or regulation. iv ACKNOWLEDGEMENTS This study was funded by the South Dakota Department of Transportation (SDDOT) and the Mountain Plains Consortium (MPC) University Transportation Center.
    [Show full text]