I would like to thank my parents, Chuck Jenkins and Sherry Williams-Jenkins, for instilling in me a love of learning that I hope to carry throughout my life. I would like to thank the Sally McDonnell Barksdale Honors College at the University of Mississippi for the tremendous resources it provides to countless students. I would like to thank the entire Department of Civil Engineering at the University of Mississippi for the teaching, guidance and friendship they have shown me.
The education I received at the university is excellent and I could never have completed this thesis without it. She helped me at every stage of my undergraduate career, from registering for my first classes in the summer of 2009, to teaching statics in my second year, to advising me on applying for graduate studies, to advising me on my thesis. The thesis presents a new type of retractable roof that adapts the revolving retractable system used at Miller Park to a non-circular stadium.
The design herein is incomplete for real-world application, but may inform future designers of considerations for the presented architecture. 44 Figure 17: From left to right: cross-sectional view of steel rail beam, concrete rail and steel wheel; elevation view of steel wheel; sectional view of wheel; cross-sectional view of steel track; cross-sectional view of concrete rail beam with arbitrary reinforcement.
INTRODUCTION
This allows roof panels to rotate around a fixed point, but with the moving ends of the panels following a non-circular path. The panel supports must be able to move relative to the panel to stay on the track. This concept allows retractable roofs with rotating panels to be used on non-circular stadiums, which is common for football stadiums and football arenas and where conventional rotating panels cannot otherwise be installed.
STRUCTURAL REVIEW
- Introduction
- Rogers Centre, Canada
- Bank One Ballpark, AZ
- Safeco Field, WA
- Minute Maid Park, TX
- Reliant Stadium, TX
- Marlins Park, FL
- Miller Park, WI
- Conclusion
The panels extend from the center of the field and come to rest on either side of the stadium. The panels on either side of the stadium can be individually adjusted to control the amount of sunlight entering the stadium. Each carrier is attached to the end of the rail with steel cables (15 inches in diameter), which open and close the roof panels.
The middle panel is 275 feet above the field; when the roof is opened, the two outer panels rest under the middle panel at the bottom of the structure. Two panels are split from the center of the field and sit above each end zone. Because of the large roof spans, the roof generates lateral deflections of more than 10 feet.
The support structure had to be designed to accommodate three different load cases: operating (associated with a maximum wind speed of 40 mph), parked (maximum wind speed of 95 mph) and secured (50 year wind speed of 146 mph)" (Blumenbaum and White 2011) The Panels'. To prevent overloading the wheels, it was necessary to find a balance between strength and stiffness.The rotation of the roof makes waterproofing difficult, and the roof has had problems with leaks.
The waterproofing at the interface of the panels now consists of a weather-stripping U-shaped foam membrane after the previous waterproofing failed (Frazer 2005).
TECHNICAL CONSIDERATIONS
- Introduction
- Technical Terms
- Retraction System
- Structural System
- Conclusion
In an axially loaded member, the axial stress is given by 𝑓= 𝑃𝐴 , where 𝑃 is the axial load and 𝐴 is the cross-sectional area of the member. In a beam, the maximum axial stress at a given point along the member is given by 𝑓 =𝑀𝑐𝐼 , where 𝑀 is the moment, 𝑐 is the distance from the section's neutral axis to its outer fiber, and I is the section's moment of inertia. Deflection in an axial member is given by 𝐷= 𝐴𝐸𝑃𝐿 , where 𝑃 is the axial load, 𝐿 is the length of the member, 𝐴 is the cross-sectional area of the member, and 𝐸 is Young's modulus: A structure that can determine structure. analyzed using statics only.
Strain in an axial member is given by =𝑓𝐸 , where 𝑓 is the axial stress in the member and 𝐸 is Young's modulus. Hinge: A connection which is free to deflect and effectively permits free rotation of the members it connects. A hinged joint may not allow truly completely free rotation, but does not interfere with rotation of the magnitude generated by structural loads.
It appears as tension on one side of the section and compression on the other side. In a beam, the maximum shear stress at a given point along the beam is given by 𝜏 =𝑉𝐴 , where 𝑉 is the shear stress and 𝐴 is the cross-sectional area of the beam. Traction Drive System: a traction system in which the thrust behind the roof ensures the friction of the bogie wheels against the rail.
Girder: A frame in which members form a series of triangles and are connected by adjustable joints so that all members carry only axial loads Ultimate Strength (𝑅𝑢): Factored load that a member or structure must be capable of . Designers must consider several complex factors, including structural resistance to track loading, structural strength of girders or bogies, frictional resistance in wheel assemblies, and lateral load resistance in assemblies. The mounts themselves do not provide power; instead, the roof is pulled along the track by steel cables attached to engines at either end of the track (Waggoner 2008).
In the traction drive system, the drive for the roof is provided by the beams themselves. In addition, the stiffness of the bogie-roof interface must be such that lateral forces cannot significantly reduce the friction between the wheels and the rail. Aspects of structural design include the ability of bogies and track to withstand applied loads within acceptable deflection parameters.
The loads on the roof come primarily from gravity, wind pressure, wind lift and retraction. Used in this thesis and the current state-of-the-art, the second philosophy is Load and Resistance Factor Design (LRFD).
DESIGN AND RESULTS
- Architectural Design
- Structural Design
- Structural Design Results and Discussion
- Carrier Recommendations
In order to prevent excessive overhang of the panels in the fully open position, additional facilities are present on either side of the building (areas B). When the panel retracts, the carrier must first move to the end of the panel. The curvature in the stadium track is slight enough over the course of the carrier length that individual wheels do not need to be able to turn, as long as the track leaves about an inch of space between the wheels and the wall of the track.
Shown in Figure 9, the shirt closest to the center of the stadium was chosen for the particular design. Fanta has a modified Pratt geometry, which was chosen to minimize the length of the chord members to increase their strength in compression. The truss was supposed to be simply supported, with the pivot end acting as a pin and the bearing end acting as a roller, as the longitudinal movement of the girders along the bottom chord of the truss would make the resistance of the girders prohibitively expensive. longitudinal movement.
When wind flows up the roof slope (Figure 11, left), it results in a downward pressure. When it flows down (Figure 11, right) the roof slope, it results in uplift pressure. The member forces developed in the structure were extraordinary; as a result, the upper chord members are all among the largest W-shaped members specified to resist compression and are made of the highest grade steel (ASTM A913, 𝑓𝑦 = 70 𝑘𝑠𝑖).
In a cantilever, most of the upper chord is in tension and most of the lower chord is in compression. Although the design is not based on pure dead load, it illustrates the basic geometry of a bent roof under calm wind conditions. Due to the wider tributary area at the bearing end of the beam, the right side develops more extreme loads, so that the maximum forces on the link are developed when the wind blows from the bearing end towards the end of the hinge (Figure 13).
When the roof is fully retracted (Figure 14), the chord loads are not as extreme due to the balancing effect of the cantilever. The maximum downward deflection is 6'9" (Figure 14, A) and the maximum upward deflection is 1'10" at the end of the cantilever (B). However, although the structure presented here is not completely feasible, it does suggest the feasibility of the project.
This thesis comes from a structural engineering point of view; therefore, a detailed mechanical design of the retraction system is beyond this scope. The bottom of the holder rolls along the X-axis of the stadium pitch and the top of the holder rolls along the Y-axis under the roof pitch.
CONCLUSION
From a functional point of view, this roof concept is not particularly important; it is possible to use a simple movable panel design which does not affect the amount of coverage provided by the roof. From an aesthetic point of view, however, this concept gives designers a new option for the geometry of the stadium and the way the roof retracts. With it, the aesthetic of the rotating roof can be applied to countless stadium architectures.
The final lesson learned from this thesis is one that all civil engineers learn at some point: there's a reason engineers don't get licenses as soon as they get their degrees. An engineer must have experience and a sense of intuition in his (or her) work that informs his decisions as much as his formal education. Learning from impractical and flawed designs, such as the one presented here, informs that experience and intuition.
Ultimately, an engineer's abilities are a sum of his training, his successes and his failures, and this thesis can now be part of that sum. Design of the retractable roof for the Florida Marlins New Ballpark.” Proc., Structures Congress 2011, ASCE, Reston, VA, 324-336. SAP2000®: Linear and non-linear static and dynamic analysis and design of three-dimensional structures; GETTING STARTED." Computers and Structures, Inc.
ENCAD Systems: Structural Analysis and Design Software.” ENCAD Systems,
