1.0
Introduction
1.1 Objective
The objective of this project was to develop a
multimedia resource that provides a background to, and an understanding of, the
various guidelines related to the construction of bridge structures seen in a
typical department of transportation (DOT) construction manual. This resource will serve as an effective
learning tool to educate young civil engineers at state DOTs about the various
aspects of bridge construction and will help flatten the learning curve for
these engineers.
2.0
Background
2.1 Purpose
The civil engineering curricula in the nation’s
engineering schools have undergone very significant changes over the past 30
years. The pressure to decrease the
credit hour requirement for a baccalaureate degree coupled, with the emergence
of other civil engineering discipline areas (namely, environmental engineering,
transportation engineering, etc.) led to drastic changes in the civil
engineering curriculum. The heavy
structures-slant of prior civil engineering curricula no longer exists. Only the first structural analysis course
(determinate structures) and one structural design course (usually concrete
design) are now required in most civil engineering curricula. DOTs can no longer assume that a young graduate
has a reasonably good grasp of structural analysis and design unless he or she took
technical electives in the structures area.
Young civil engineering graduates have very limited or no exposure to
bridge design and construction, even after completion of a structures option. Consequently they need significant training
to deal with bridge construction issues in their DOT jobs. This project was undertaken to meet this
important training need of these young engineers
3.0
Project Tasks
3.1 Design of Basic Structure of Training
To create an effective multimedia resource for
bridge engineers, it was important to pattern it after a standard construction
manual. The Alabama Department of
Transportation (ALDOT) construction manual for bridge structures (ALDOT, 2002)
was selected due to its accessibility.
This manual is readily available online in pdf
format at the ALDOT homepage.
The bridge structures portion of the ALDOT manual is presented in the resource as two major sections entitled “Substructures” and “Superstructure” (see Figure 3-1). The Substructures section deals with construction of the base of the bridge. This section is further subdivided into three subsections dealing with Bridge Foundations, Bridge Abutments, and Bridge Bents or Piers. The Superstructure section covers the section of the bridge that motorists drive upon. It is subdivided into four sections dealing with Bridge Bearings, Beams or Girders, Bridge Deck and Bridge Railing.
The primary weakness of the ALDOT manual for training purposes is that it contains mostly text. There is very little visual material about construction systems or processes that a young engineer can quickly grasp. Only a few black and white images and graphs are included in the manual. No effort was made to illustrate the concepts presented within the document. Pictures could be used to answer questions like, “How are foundations installed? What equipment and procedures are used to install a pile? What does a bridge bearing look like?” As such questions arise in a young civil engineer’s mind, they can be answered more quickly and more thoroughly by including illustrations/graphics, images and video clips.
During this project, the 500+ page
ALDOT construction manual was painstakingly converted from pdf
format into the web-based format, html, using Microsoft’s FrontPage. An html file was created for each section and
subsection. These files were used to
develop the multimedia resource. Also,
the construction manual was included within the resource (pdf
format) as an accessible document, eliminating the need for a reader to visit
the ALDOT homepage to refer to the manual.
Tentative plans have been made to place the training tool on the
Department of Civil and Environmental Engineering website at the
Figure 3-1. Contents of bridge structures portion of the
ALDOT Construction Manual
The contents of the training tool contents were designed to include four primary subject areas, as outlined in Table 3-1. Topics III and IV, titled “Substructure” and “Superstructure,” track the bridge structures portion of the ALDOT construction manual.
|
Table 3-1 Content of Web-Based
Training Tool |
||
|
I. HOME |
Direct Bearing |
Mild Steel Rocker |
|
Purpose |
Rock Footing |
Expansion Bearings |
|
Contact Information |
Spread Footing |
Slide Plate Bearing |
|
Feedback |
Seal Conc. Footing |
Sliding Cum Rocker Bearing |
|
General Introduction Video |
Pile Foundations |
Steel Roller Cum Rocker Bearing |
|
II.
INTRODUCTION |
Pile Hammer |
Reinforced Conc. Rocker Bearing |
|
Classification of Bridges |
Hammer Accessories |
Bronze Bearing Assemblies |
|
By Material |
Protection |
Elastomeric Bearings |
|
Steel Bridges |
Penetration |
Type 1 and Type 2 |
|
Concrete Bridges |
Location |
Type 4 and Type 5 |
|
Timber Bridges |
Determine Adequate Bearing |
Temperature Adjustment |
|
Masonry Bridges |
Piles Placed in Seal
Concrete |
Beams or
Girders |
|
Composite Bridges |
Drilled Shaft Foundation |
Structural Steel Beams |
|
By Objective |
Construction Methods |
Prestressed Concrete Beams |
|
Highway Bridges |
Abutments |
Tensioning Devices |
|
Railway Bridges |
Introduction |
Pre-tensioning System |
|
Combination Bridges |
Types |
Post-tensioning System |
|
Aqueduct Bridges |
Construction |
Tendon Splices |
|
Covered Bridges |
Bents
or Piers |
Cast in Place Concrete Beams |
|
By System |
Pier
Types |
Deck |
|
Arch Bridges |
Wall |
Construction |
|
Beam Bridges |
Capped Pile |
Grooving |
|
Cable-stayed Bridges |
Tee type |
Checklists |
|
Suspension Bridges |
Cap and Column |
|
|
Cantilever Bridges |
Multiple Columns |
Curing |
|
Movable Bridges |
Bent Classification |
Railing |
|
Truss Bridges |
Reinforced Concrete Bent |
Precast Barrier Rails |
|
Girder Bridges |
Pile Bent |
Cast in
Place Barrier Rails |
|
Rigid Frame Bridges |
Pre-cast, Post-tensioned Box
Bents |
Slip Formed Barrier Rails |
|
III.
SUBSTRUCTURE |
IV.
SUPERSTRUCTURE |
V. RESOURCES |
|
Foundations |
Bridge Bearings |
Search |
|
Cofferdams |
Types |
Glossary |
|
Choice |
Fixed Bearings |
ALDOT Construction Manual |
|
Types |
Rocker |
References |
|
Footings |
Cast Steel Hinge |
|
The introduction serves as a preamble to the two major ALDOT
sections. This introductory material
does not exist in the current construction manual. It enables the user to better understand the
sections related to the substructure and superstructure. It presents an overview of a wide spectrum of
highway bridge types and the materials used in their construction. It also provides definitions for the most
common terms used in bridge construction.
Numerous photos/slides, videos and graphics are included in the introduction
to illustrate the bridge construction process.
The voluminous contents, listed in Table 3-1, made it a challenge to present the layered material in a user-friendly, web-based format. It was critical that the user be able to navigate easily through the resource material without confusion or loss of reference. In addition to developing the web format for presenting the material, considerable effort was expended to collect, convert and organize the resource material included in the various topics. The design of the web page for the training tool and the collection of resource material are discussed in the following sections.
3.2 Design of Web Page
Two important features dictated the selection and use of any particular software for web page design. The first was the ease of creation of a web page without significant prior knowledge of html. The second was the availability of a decent navigation tool-menu bar for easy access of the resource material.
Microsoft’s Frontpage software is one of the easiest means used for creating a professional web page without prior knowledge of html. Frontpage makes use of a graphical user interface. A very simple website was created using the html files of the ALDOT bridge construction manual and a few color images of bridges acquired from the Internet. Unfortunately, this site proved to be too basic. It consisted of three frames: one to highlight the title, another to navigate the site and a final frame to display information. This website, shown in Figure 3-2, was developed for trial purposes only.
Figure 3-2. The original multimedia resource
After Frontpage, the next biggest commercial software for designing web pages is Macromedia’s Dreamweaver. Like Frontpage, Dreamweaver has a graphic user interface for designing websites. However, Dreamweaver has more functional options than Frontpage. In the early phase of this project, web pages were developed using both software packages. After comparison, Frontpage was chosen because of its simplicity.
3.2.1 Selection of Navigation Tool
Considerable time and effort were devoted to zeroing in on an acceptable navigation tool. This was by far the most difficult task in the web page design. Macromedia offered a program tool called Flash to develop advanced features. Flash is a movie making software package for web based content. In other words, one can create an elegant navigation tool as a mini movie and publish it on a web page. Several “Flash movie” navigation menus are offered as free downloads on the Internet. For the purposes of this project, many of these flash movies were tested. For example, the screenshot displayed in Figure 3-3 below appears to be an acceptable navigation tool for the multimedia resource. While it is elegant and can provide a functional navigational tool interface, it is fairly difficult to create and edit. Just like a cartoon animation, Flash movies consist of several layers of animation frame sequences. The ability to change a single submenu link would require either a complete redraw of the animation or searching for the frame to edit at the proper point in time of the animation sequence. Since the training tool is a dynamic resource for bridge construction, it was essential that minor updates not become a major hassle. For this reason, use of “Flash Movie” navigation menus was abandoned.
Figure 3-3. Flash based navigation tool
At this point, it was decided to return to the roots of web page design. Instead of searching for an all-in-one software package like Dreamweaver, a search was made on the Internet for a powerful web navigation tool that is fairly easy to edit. From dynamic html to JavaScript, many different versions of menus were tested. Figure 3-4 is an example of a JavaScript that highlights submenus as the mouse rolls over the object. This menu implementation does not allow the user to see the tree-like structure of the document. After the submenu is clicked, information is displayed but the submenus disappear immediately. Hence, the JavaScript example was tested but later discarded as unacceptable for the training tool.
Figure 3-4. JavaScript navigation
tool
A dynamic html menu tree, very similar to Windows Explorer found in most Windows-based operating systems, was tested. As seen in Figure 3-5, when folders are opened their contents are displayed. When content is displayed in the right-hand side, submenus appear as folders under the main topic. Unfortunately, in large documents, several submenus require a significant amount of the viewing space. To see the whole tree structure of the document the user must manipulate scrollbars, which can become a nuisance to use. In addition, the Windows Explorer style menu is not dynamic. In other words, the submenus folders do not close automatically. If the user chooses a new topic he or she must click to close the previous topic folder or precious viewing space is wasted. For this reason, this dynamic html menu tree was also abandoned.
Figure 3-5. Dynamic HTML navigation
tool
Finally, the slide tree menu from Open Cube (http://www.opencube.com/) was selected because its features closely met the training tool requirements. At first, Open Cube’s dynamic menu tree was considered inadequate. Due to limitations of dynamic html, the slide tree menu only allowed one submenu per main menu topic. For a 500-page technical document on bridge construction, this limitation is unacceptable. After consulting with Open Cube’s technical support, a java applet version of the slide tree menu was discovered. The java applet permits as many submenus as needed. The only limitation is the amount of space provided in the web design. This slide tree menu shown in Figure 3-6 automatically closes submenus when a new topic is selected. The slide tree menu is fairly easy to revise and edit. While java applets can be edited with a simple text editor like notepad, Open cube offers a graphic user interface to edit its slide tree menu called Applet composer. Here the developer can easily make changes like removal of menus or submenus. The selection of this Open Cube software completed the search for a navigation tool. This software could be used with Dreamweaver or Frontpage.
Figure 3-6. The slide tree menu
3.3 Generation of Resource material
To develop a useful training tool,
it was important to collect color images and slides of bridge structures,
components and construction processes from multiple sources. A variety of media including video clippings,
slides, and color diagrams were collected from an array of Internet websites, ALDOT
and other state DOTs. Several hundred
slides and photographs provided by ALDOT were scanned and converted into
electronic files. These electronic
images were sorted based on the topics covered in the training tool. This conversion was carried out with the help
of assistants provided by the
Figure 3-7. Text illustrated with
a graphic
Figure 3-8. Illustration of a bridge
foundation construction procedure
Galleries of different bridge
types from around the world were created using Microsoft Word. From arch bridges in
The inclusion of a large number of photos, slides, and graphics required
that they be accessible in a user-friendly fashion. This essentially meant that thumbnail
galleries be developed for the various topics covered in the training
tool. Without these galleries, the user
would have had to scroll through a document containing a large array of photos
as shown in Figure 3-9. Such extensive
scrolling to view the figures was clearly unacceptable.
Figure 3-9. Gallery of arch bridges
Using the sorted photos, thumbnail galleries for each appropriate topic were created for insertion in the training tool. Figures 3-10 and 3-11 show typical thumbnail galleries developed for concrete bridges and pile foundations.
Figure 3-10. Thumbnails of concrete
bridges
Figure 3-11. Thumbnails of pile foundations
These thumbnail galleries allow the user to view small images on a single page. By clicking on any of the smaller images, a larger, detailed photo of the image will appear as shown in Figure 3-12.
Figure 3-12. Enlarged photo of a concrete
bridge from the thumbnail gallery
Navigation of the thumbnail gallery is provided at the top of each enlarged image. The user can choose among the following options:
- Previous: click here for the previous enlarged photo in the gallery
- Next: click here for the next enlarged image in the gallery
- Index: click here for the single page view
Over 30 different thumbnail galleries were created.
3.3.2 Development of Video
Clips
The inclusion of video clips in the training tool offered another challenge. Most of the available video resources were on tape and not in electronic format. ALDOT films on bridge construction were first converted into a video CD format and copied onto a CD-ROM. These VCD files were then converted into MPG files for viewing with the aid of Windows Media Player. A software program called Cineplayer was used to accomplish this task. Cineplayer is a video file editor available from Ravisent technologies for conversion of VCD files into MPG files. MPG files are easily recognizable by Windows Media Player. Over 30 video clippings were made and inserted into the appropriate sections of this resource. Unfortunately, MPG files require a lot of disk space. For example, the video files for this resource material required two gigabytes of disk space. A typical video clipping viewed using the media player is shown in Figure 3-13.
In the future, the video files could be saved as RM files. The RM files are considerably smaller in size but require users to have Real Player software installed on their systems. These compact files may allow the training tool to be made available on one CD.
Figure 3-13. Video Clipping
3.4 Final
Design of Web Page
With an elegant but simple navigation tool, the graphically illustrated Microsoft word files were converted into web pages and incorporated into the final design of the multimedia resource for bridge construction engineers. The menu navigation links for the substructure and superstructure sections correspond directly to the topics found in the original bridge construction manual. The final web design follows a three-frame structure. The first frame at the top provides a banner heading for the resource. The second frame, below the banner on the left side, displays the slide tree menu for document navigation. The final frame, on the right side below the banner, displays the contents as shown in Figure 3-14. The initial splash screen (Figure 3-15) is a rotating gallery of images displayed when the web page is accessed. As the web document is refreshed, a new image of a bridge is shown. As a topic is selected, information is viewed on the right-hand side. The slide tree menu automatically closes a topic when a new topic is selected.
Figure 3-14. Information on piers displayed on the right side
of the resource
Figure 3-15. Initial splash screen
displayed when web page is accessed
The pile footing section was selected to illustrate the information shown to the user when one of the topics is accessed. The information is shown in detail in Appendix A.
4.0
Potential Benefits of the Project
The availability of this multi-media resource material will significantly enhance the ability of the nation’s DOTs to effectively train young engineers in the topic of bridge construction. The flattened learning curve that could result from the use of this tool can reduce the cost of training these engineers. Also, easy access to the resource material can improve the safety of bridge structures by imparting a better understanding of the construction process for these structures.
5.0
Conclusion
The availability of advanced web design tools at affordable costs made it possible to undertake and complete this project. This web based training tool for bridge construction engineers is a dynamic resource. It provides an interactive learning environment via the graphic illustrations and video files. This web-based resource can also be continuously updated. New concepts and topics can be incorporated into this online tool as new technologies in bridge construction emerge.
6.0 References
6.1 Publications that Provided
Project Resources
Alabama Department of Transportation
(ALDOT), Construction Manual,
Department of
Transportation, Construction Bureau,
Bazant, Bazant, “ Methods of
Foundation Engineering,” Elsevier/North Holland, Inc,
Brown, Dan A. and Kenneth W. Weinel,” Guidelines for the selection, Design and
construction of drilled shaft foundations for bridges in
Fustok, M. and M.Alemi, “Bridge Construction
Inspection,” Bridge Engineering Hand Book, Ed. Wai-Fah
Chen and Lian Duan , CRC
press, Boca Raton, FL, 2000.
Liebenberg, A.C., “Concrete Bridges:
Design and Construction,” John Wiley and sons, Inc.,
Raju, N.K., “ Prestressed Concrete,” Tata McGraw-Hill Publishing Company Limited,
Tonais, Demetrios E., “ Bridge
Engineering,” McGraw-Hill, Inc,
White, Kenneth R., John Minor,
Kenneth N. Derucher and Conrad .P. Heins, Jr., “ Bridge Maintenance inspection and evaluation,”
Marcel Dekker, Inc, 270 Madison Avenue, New York, NY
10016, 1981.
Victor, D.Johnson,
“Essentials of Bridge Engineering,” Oxford & IBH Publishing Company Pvt.Ltd.,
66 Janpath,
6.2 Websites that Provided Project
Resources
1.
http://www.bb.brantacan.co.uk/bridges.htm
2.
http://www.media.uwe.ac.uk/masoud/projects/bridges/beam/text/beam.htm
3.
http://www.bb.brantacan.co.uk/beamtwo.htm
4.
http://www.gerwick.com/experience.asp?Version=Long&StructureTypeID=8
5.
http://www.flatheadcd.org/bridges/bridges.html
6.
http://www.matsuo-bridge.co.jp/english/bridges/basics/arch.shtm
7.
http://www.matsuo-bridge.co.jp/english/bridges/basics/cablestay.shtm
8.
http://www.matsuo-bridge.co.jp/english/bridges/basics/suspension.shtm
9.
http://www.matsuo-bridge.co.jp/english/bridges/basics/truss.shtm
10.
http://www.matsuo-bridge.co.jp/english/bridges/basics/rigidframe.shtm
11.
http://www.dot.state.ia.us/
12.
http://www.dot.state.az.us/roads/bridge/gallery.asp
13.
http://www.historicbridgefoundation.com/ipages/construct/construct.html
14.
http://www.historicbridgefoundation.com/ipages/links/links.html#link2
15.
http://www.media.uwe.ac.uk/masoud/projects/bridges/arch/text/arch.htm
16.
http://www.media.uwe.ac.uk/masoud/projects/bridges/suspens/text/suspens.htm
17.
http://www.media.uwe.ac.uk/masoud/projects/bridges/text/glossary/glossary.htm
18.
http://bridgepros.com/tomoka/Photo%20pages/deck%20pour_photos_1.htm
19.
http://www.wattave.org/weekly_photos.htm
20.
http://www.granor.com/strubrg/pottype.html
21.
http://www.lrl.usace.army.mil/cd/McAlpine/Photos/01APR01/
22.
http://www2.state.ia.us/dot/specifications/April_2001/conmanual/cm_files/CM%2011.20.htm#Pile%20Driving
23.
http://www2.state.ia.us/dot/specifications/April_2001/conmanual/cm_files/CM%2011.30.htm#11.31
24.
http://www2.state.ia.us/dot/specifications/April_2001/conmanual/cm_files/CM%2011.60.htm#11.61
25.
http://www2.state.ia.us/dot/specifications/April_2001/conmanual/cm_files/CM%2011.70.htm#11.71
26.
http://bridge.tongji.edu.cn/bridges/beam/beam.htm
27.
http://www.design-technology.org/beambridges.htm
28.
http://www.bb.brantacan.co.uk/beam.htm
29.
http://www.childs-ceng.demon.co.uk/parts/bearing.html
30.
http://www.acsu.buffalo.edu/~iahn/rt400/bearing.html
31.
http://www.merl-ltd.co.uk/Industry_sectors/civil.htm
32.
http://www.aturgroup.com/rubber/sub_rtm.htm
33.
http://pghbridges.com/basics.htm
34.
http://www.bikerizzo.com/downeast_trail/downeast_photo_gallery.htm
35.
http://www.pbs.org/wgbh/buildingbig/glossary.html
36.
http://www.ci.nyc.ny.us/html/dot/html/bridges/opener.html#swing_span
37.
http://newton.dep.anl.gov/askasci/eng99/eng99141.htm
38.
http://www.co.multnomah.or.us/dscd/transportation/bridge/bridge_types/bridge_types.html
39.
http://www.aframeortwo.com/bridges.html
40.
http://www.wyattdp.com/bridges.htm
41.
http://www.richmangalleries.com/bridges.htm
42.
http://eroosevelths.pgcps.pg.k12.md.us/~templin/bridgeproj/bol8.html
43.
http://www.bdcorr.ca.gov/cppd/more%20for%20less/4-b.pdf
44.
http://www.gov.calgary.ab.ca/centrestbridge/updatefeb23.html
45.
http://www.nrc.ca/irc/cbd/cbd081e.html
46.
http://www.hbfleming.com/HBFleming%20Cofferdam.html
47.
http://cem.www.ecn.purdue.edu/CEM/Research/coffer.htm
48.
http://www.dot.ca.gov/hq/esc/construction/Manuals/Foundation/ch.12_cofferdams_and_seal_courses.pdf
49.
http://info.urbanengineers.com/cmci/inspman/70411.htm
50.
http://www.dfwspecs.com/pdf/Div7.pdf
51.
http://www.lyndonroad.com/pphotos.html
52.
http://bridge.tongji.edu.cn/bridges/beam/Continuous%20beam/content.htm
53.
http://www.nireland.com/bridgeman/Dictionary.htm
54.
http://www.aone1.co.kr/dieselpilehammer.htm
55.
http://www.casefoundation.com/PDF%20Documents/Bath%20Woolwich%20Bridge.PDF
56.
http://www.civl.port.ac.uk/comp_prog/bridges/main1/page7.html
57.
http://www.tpub.com/inteng/1d.htm
58.
http://www.faculty.fairfield.edu/jmac/rs/bridges.htm
59.
http://manuals.dot.state.tx.us/dynaweb/colbridg/geo/@Generic__BookTextView/6381;pt=6325
60.
http://www.casefoundation.com/PDF%20Documents/Bath%20Woolwich%20Bridge.PDF
61.
http://www.dot.state.al.us/Bureau/Construction/Spec1992/3750.pdf
62.
http://www.glfconstructioncorp.com/services1.html#foundations
63.
http://www.usace.army.mil/inet/usace-docs/eng-manuals/em1110-2-2906/basdoc.pdf
64.
http://www.usbridge.com/truss.html
65.
http://www.aone1.co.kr/hypilehammer.htm
66.
http://www.techstar-inc.com/pdf/Potbear.pdf
67.
http://www.info.gov.hk/napco/llink2.html
68.
http://www.dot.state.ny.us/structures/innovate/chan17m1.html
69.
http://www.brantacan.co.uk/pageindex.htm
70.
http://www.bizave.com/cgi-bin/photoalbum.cgi?photoalbum=pdxbridges&slidetag=Steel
71.
http://www11.myflorida.com/structures/botm/roosevelt/roosevelt.htm
72.
http://images.google.com/imgres?imgurl=www.unitedtoll.com/images/Const006A.jpg&imgrefurl=http://www.unitedtoll.com/ArpConst/arpconst006.htm&h=289&w=440&prev=/images%3Fq%3Dconstruction%2Bof%2Babutments%26svnum%3D10%26hl%3Den%26sa%3DN
73.
http://www.lrl.usace.army.mil/olmsted/Lock/Active/20010115/img018.htm
74.
http://civilzone.com/seo-hae-eng.html
75.
http://www.yeongjongbridge.com/young/habugon/04-ill06.asp
76.
http://images.google.com/imgres?imgurl=www.superstitionfreeway.com/images/HOV2.jpg&imgrefurl=http://www.superstitionfreeway.com/photo.html&h=459&w=679&prev=/images%3Fq%3Dpier%2Bconstruction%26svnum%3D10%26hl%3Den%26sa%3DN
77.
http://www.vulcanhammer.net/download/ei02g001.pdf
78.
http://www.willamettewtp.com/pile_hammer.htm
79.
http://www.corusconstruction.com/indexes/idxph001.htm
80.
http://images.google.com/imgres?imgurl=itri.loyola.edu/compce/fh0b_071.jpg&imgrefurl=http://itri.loyola.edu/compce/b_14.htm&h=461&w=681&prev=/images%3Fq%3Dprestressed%2Bgirders%2B%26svnum%3D10%26hl%3Den%26sa%3DG
81.
http://images.google.com/imgres?imgurl=www.aku.ac.ir/faculty1/aliniamm/Structural%2520Slides/beams/p/IMG0046.jpg&imgrefurl=http://www.aku.ac.ir/faculty1/aliniamm/Structural%2520Slides/beams/Box%2520girders%2520constant%2520depth.htm&h=427&w=640&prev=/images%3Fq%3Dprestressed%2Bconcrete%2Bgirders%2B%26svnum%3D10%26hl%3Den%26sa%3DG
82.
http://www.city.winnipeg.mb.ca/publicworks/Engineering/2002-01-Photos.asp
83.
http://bridge.tongji.edu.cn/bridges/arch/Rigid%20Framed/content.htm
84.
http://www.schnabel.com/schnabel/index.shtml
85.
http://www.usace.army.mil/inet/usace-docs/armytm/tm5-818-1/ch-10.pdf
86.
http://www.centurysteel.com/gallery/bridges.htm
87.
http://nisee.berkeley.edu/leonhardt/html/steel_suspension_bridges.html
88.
http://bridge.tongji.edu.cn/bridges/beam/steel%20truss/content.htm
89.
http://www.gerwick.com/document.asp?DocumentID=3
90.
http://www.beg.soton.ac.uk/index.htm
91.
http://www.design-technology.org/suspensionbridges.htm
92.
http://images.google.com/imgres?imgurl=www.dot.state.ga.us/homeoffs/bridge_dsgn.www/sidney/approach/coffer.jpg&imgrefurl=http://www.dot.state.ga.us/homeoffs/bridge_dsgn.www/sidney/approach/cofferdm.htm&h=280&w=420&prev=/images%3Fq%3Dcofferdams%26start%3D20%26svnum%3D10%26hl%3Den%26sa%3DN
93.
http://pghbridges.com/termsBrg.htm
94.
http://www.bridgesite.com/bridgephoto.htm
95.
http://www.th.gov.bc.ca/BCHighways/jhbridge/maps.html
96.
http://www.iowariverbridge.org/servlet/com.hntb.cs.servlets.ImageManagement?option=1&type=1&projectid=7
97.
http://eroosevelths.pgcps.pg.k12.md.us/~templin/bridgeproj/bol6.html
98.
http://www.richmangalleries.com/truss_bridges_iii.htm
99.
http://www.versasteel.com/CoventryRI.htm
100.
http://community-2.webtv.net/DAROSAMARCIELII/TrussBridgesof/
Appendix
A
Screenshots of Resource Material Displayed to the User when
“Pile Footings” is selected from Slide Tree Menu (Figs A1-A6)
Figure A-1. Information on pile footings when selected from the menu tree
Figure A-2. More content on pile footings
as the user scrolls down
Figure A-3. Pile photos seen as the user scrolls further down
Figure A-4. Final section of content
on pile footings with video and gallery links
Figure A-5. Photos displayed when
the “pile footing” gallery link is selected
Figure A-6. Video displayed when the “pile location” video
link is selected