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Titanium Bridge Report.docx - GREAT AMERICAN MOTORCYCLE TOURING

By Bradley Howard,2014-12-12 02:32
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The basis of conceptual design for the pedestrian bridge is a basket handle arch.Our analysis will allow us decide whether individual support elements

    Department of Civil Engineering and Materials Science

    10200 Euclid Avenue

    Cleveland OH 44106

    www.case.edu

Team Members and Contact Information

     Professor Dario Gasparini Ph.D.

     Professor of Civil Engineering Case Western Reserve University

     Team Advisor

    dag6@case.edu 216-368-2699

     http://civil.case.edu/people/dag6

    Kenneth Craymer Graduate Student, Materials Science and Engineering

     klc21@case.edu

    Julia German Undergraduate, Materials Science and Engineering

     jmg91@case.edu

    William Holman Jr. Undergraduate, Department of Civil Engineering

     wxh68@case.edu

    Kane Riggenbach Undergraduate, Department of Civil Engineering

     krr18@case.edu

    Introduction

    Table of Contents I. Design Criteria Review

    A. DMTC Requirements

    B. CSX Railroad Requirements II. Conceptual Design

    A. Introduction to Design

    B. Inspiration for Design

    C. Design Logic and Structural Importance.

    D. Design Conclusions

    III. Continued Design Process

    A. Structural Analysis

    B. Constructability

    C. Lighting

    IV. References

    I. Design Criteria Review

    The conceptual design process was guided by the Defense Metals Technology Center (DMTC) and CSX Transportation (CSXT) and local building code requirements. It was critical for the design team to calculate both aspects into the design for a successful project. In doing so, this design integrates all necessary requirements.

A. DMTC Requirements

    The DMTC has required all the structural components to be Titanium, be it

    commercial or armor grade. Also during the orientation lunch, the panel

    requested a United States Titanium supplier to help support the national

    economy. On the side of the Quaker Square Inn, the bridge must also tie in with

    the second floor balcony to allow elevator access for the handicapped. Finally,

    the panel recommended the opposing side of the bridge allow potential

    integration with a new building but currently exit the deck onto the parking lot.

B. CSXT Requirements

    The CSXT requirements were far more complex for traversing the Right of Way

    1(ROW) of the tracks. The most pertinent requirements are noted as:

    1. Clearance- The standard horizontal clearance is typically 25’ but no

    less than 18’ perpendicular to the tracks. The vertical clearance

    standard measured from the top of the track to the lowest point on

    the bridge shall not be smaller than 23’.

    2. Drainage- Drainage from the bridge shall be collected by drain pipes

    and cannot dump inside of the 25’ clearance mark.

    3. Pedestrian Bridge Specific No intermediate piers are permitted

    between the tracks and bridges must be completely enclosed to

     1 The requirements were given by the DMTC to each team and are available online at

    http://transportation.ky.gov/contract/Memos/CSX%20Criteria%20for%20Overhead%20Bridges.pdf

    prevent users from dropping debris onto the track. The below image

    best summarizes the distance requirements and was taken directly

    from CSX.

Figure 1 (Courtesy CSX Transportation)

    II. Conceptual Design

    In addition to the AutoCad and Solidworks models, detailed explanations of the design concepts are provided to show the structural integrity and aesthetics of the design.

Key:

     -Deck: The pedestrian walkway itself.

     -Arch: Two main arches crossing the tracks

    -Horizontal frame: horizontal tubular bar members connecting the two

    arches

    -Vertical frame: Titanium bar members orthogonal to the deck

    connecting the deck to the arches and holding glass panels in place.

A. Introduction to Design

    The basis of conceptual design for the pedestrian bridge is a basket handle

    arch. Basket handles are a modification of the traditional twin arch design.

    Figure 2 shows a comparison of the basket handle and traditional arch.

    Notice in the basket handle at left, the arches are tilted inward at an angle

    instead of perpendicular to the deck as seen in the picture of the arch on the

    right.

    Figure 2 ([Left] Courtesy Bunner, Matthew [Right] Courtesy Jacky and Mike Smith)

    The frame members connecting the deck to the arch are proposed as either titanium square or rectangular bar. They will not only be the tension elements holding the deck in place but also the framing for the polycarbonate enclosure. The polycarbonate enclosure will be a more aesthetically pleasing choice over the titanium wire mesh, but the option is left open for both ideas.

    Detailed structural analysis will allow the team to finalize the exact specifications and dimensions of the deck, trusses, and arches. Titanium sheet and plate will be used as the main walkway of the deck connected by titanium bar members. Polycarbonate sheets will be used to form the enclosure providing protection for wind and noise while keeping the CSXT lines clear of debris. Along the enclosure, half cut tubular titanium will act as the drainage system to carry the water off the right of way.

    The arch itself utilizes circular tubular pipe. Pipes have greater moments of inertia and incur greater stiffness than solid sections for the amount of material used.

    B. Inspiration for Design

    The primary inspiration for a basket handle design was a structural and aesthetic one. Tubular frame arches provide superior structural integrity. Aesthetically, the design utilizing the tubular basket handle is modernistic. Since Titanium is on the cutting edge as a structural material, the design shows the modern and clean cut appearance befitting the metal.

    Inspirationally speaking, the works of Santiago Calatrava have impacted the project. Specifically, the Campo Volantin Bridge has served as a primary

    inspiration along with impressive Manrique Bridge. In the late 90’s, Calatrava

    blended artistic beauty with structural design to create some of the most

    2memorable bridges in Europe.

Figure 3 Manrique Bridge (Courtesy Santiago Calatrava)

     2 Calatrava, Santiago.

    The team feels this modern tubular basket handle bridge will complement the rejuvenated University of Akron’s Campus as well as the renovated Quaker Square Inn. It will be a perfect tie together for both sides of campus and improve the aesthetics in the area.

    C. Design Logic and Structural Importance

    In accordance with the requirement of seeking out a Titanium manufacturer within the United States, The team has been in contact with United Titanium, an Ohio based Titanium manufacturer and distributor.

    United Titanium is one of the world class leaders in Titanium and is located in very close to the bridge site in Wooster Ohio. Their wide variety of plate, bar, tube, and fastenings in stock can serve all bridge components. This greatly cuts down custom fabricated pieces and decreases the overall cost while increasing constructability. Another benefit is the increased amount of off site fabrication which will also greatly increase constructability and reduce costs.

    The design team recommends United Titanium as a possible supplier to the DMTC. Included in the design documents is one of the requested brochures including contact information. They are very well equipped and close to the University of Akron and the DMTC. In the event the DMTC chooses another supplier, the components of the bridge are readily available through multiple other companies, thus not affect constructability or initial fabrication costs. The design calls for a “tied arch” basket handle which will greatly help the foundation design and load capabilities. The tied arch design allows for an increase in structural rigidity and greatly reducing the necessary foundation work for an arch.

Figure 4 (Untied Arch System)

    Figure 4 is a basic distributed loading example of a plane arch distributing the load into a vertical and horizontal component on each side. A large foundation is required to contain the arch system which is both cumbersome and costly.

Figure 5 (Tied Arch System)

    Figure 5 shows a simplified version of the tied arch in the team’s design which offers better structural stiffness and reduces the foundation size of figure 4. The tied system eliminates a horizontal load component allowing a cheaper and more effective foundation which will undoubtedly be more aesthetically pleasing.

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