The students at UAF have done it again! Every year hardworking students in the construction and engineering programs research, design, and build a beautiful and unique Ice Arch on the UAF campus. See pictures of the 12-foot arch and read the write-up of the project by the President of the UAF AGC Student Chapter, Elliott Anderson, below!
Students working on the Ice Arch in the winter light.
Design Phase:
The 2016 Ice Arch was designed primarily to utilize transparent ice blocks, as this design has not been used since the 2012 arch. Instead of constructing one arch, the design included both an upper arch and lower arch which were connected by steel cables supporting a steel ornament. The upper arch stood at 12.5 feet and the lower arch at 5 feet. Constructing with block ice eliminated the need for constructing forms, freezing the ice, and tipping the structure once completed.
Structural analysis of the arch was conducted and the design was found to lie well within the maximum stress tolerance for ice. Ice cannot retain its structure in tension, therefore it must be in compression. The catenary curve design ensures that the stress on the ice is largely in compression, mitigating destructive forces.
The 2016 Ice Arch was designed primarily to utilize transparent ice blocks, as this design has not been used since the 2012 arch. Instead of constructing one arch, the design included both an upper arch and lower arch which were connected by steel cables supporting a steel ornament. The upper arch stood at 12.5 feet and the lower arch at 5 feet. Constructing with block ice eliminated the need for constructing forms, freezing the ice, and tipping the structure once completed.
Structural analysis of the arch was conducted and the design was found to lie well within the maximum stress tolerance for ice. Ice cannot retain its structure in tension, therefore it must be in compression. The catenary curve design ensures that the stress on the ice is largely in compression, mitigating destructive forces.
The catenary arch design was analyzed in SAP, a finite element software, and indeed showed that very little axial stress was applied to the points along the arch. No moment analysis was necessary since the arch will be built using false works of which were only removed once the entire construction of both arches were completed.
The arch was analyzed in 6” segments to determine the tensile and compressive stress at each segment. The legs of the arches were fixed at initial construction, and produce an axial stress of 16.93 psi on the upper arch and 3.93 psi on the smaller arch. Because this design follows the exact equation for the catenary curve, very little compressive axial stress is applied to the arch. As the maximum allowable stress for ice is approximately 725.19 psi, the design of the arch lay well within the structural parameters.
Construction Phase:
The construction of the arch spanned over approximately seven weeks and was constructed in three phases: the lower arch, the upper arch, and the steel cable and ornament. Several freshman in addition to upper classmen participated in the construction process. To represent the spirit of CEM, a steel nanook cutout with the letters “UAF” was hung from the steel cable supports. The ice blocks were purchased from Ice Alaska and cut into ten inch cubes to ensure they would not exceed thirty-five lbs. Approximately 60 blocks total were used for both arches.
The first phase of construction began with the lower arch, and once the falsework was in place, blocks were stacked on either side and joined with a capstone in the center. The blocks were ground and angled to ensure full contact between both sides of the blocks. Once full surface contact was reached, water was poured on the block surface and another block placed on top with applied pressure. Within seconds the blocks freeze and over time become a single ice structure. Upon completion of the upper arch, holes were drilled in both arches for the seven steel cable
supports. The design intention was for the lighting and cables to represent sun rays, ultimately symbolizing Alaska’s “midnight sun”.
The arch was completed shortly before the E-Week, an annual event put on by the individual engineering departments within the College of Engineering and Mines to help reach out to children of all ages and expose them to the opportunities within engineering. The ice arch was a stimulating display which drew much interest from a wide array of both children and parents. Not only do demonstrations of engineering projects expose future students to the opportunities within engineering and construction, but also motivates current students to apply the knowledge learned in the classroom to everyday applications.
Through the entire process of design and construction of the annual ice arch, we as students are exposed to applicable engineering projects that we will utilize once in the workforce.
We would like to thank AGC for your support, as without it we would be unable to have these unique opportunities. Watch for more updates on our work in the coming months as we'll be participating in the Steel Bridge Competition and the Concrete Canoe Competition!
Construction Phase:
The construction of the arch spanned over approximately seven weeks and was constructed in three phases: the lower arch, the upper arch, and the steel cable and ornament. Several freshman in addition to upper classmen participated in the construction process. To represent the spirit of CEM, a steel nanook cutout with the letters “UAF” was hung from the steel cable supports. The ice blocks were purchased from Ice Alaska and cut into ten inch cubes to ensure they would not exceed thirty-five lbs. Approximately 60 blocks total were used for both arches.
The first phase of construction began with the lower arch, and once the falsework was in place, blocks were stacked on either side and joined with a capstone in the center. The blocks were ground and angled to ensure full contact between both sides of the blocks. Once full surface contact was reached, water was poured on the block surface and another block placed on top with applied pressure. Within seconds the blocks freeze and over time become a single ice structure. Upon completion of the upper arch, holes were drilled in both arches for the seven steel cable
supports. The design intention was for the lighting and cables to represent sun rays, ultimately symbolizing Alaska’s “midnight sun”.
The arch was completed shortly before the E-Week, an annual event put on by the individual engineering departments within the College of Engineering and Mines to help reach out to children of all ages and expose them to the opportunities within engineering. The ice arch was a stimulating display which drew much interest from a wide array of both children and parents. Not only do demonstrations of engineering projects expose future students to the opportunities within engineering and construction, but also motivates current students to apply the knowledge learned in the classroom to everyday applications.
Through the entire process of design and construction of the annual ice arch, we as students are exposed to applicable engineering projects that we will utilize once in the workforce.
We would like to thank AGC for your support, as without it we would be unable to have these unique opportunities. Watch for more updates on our work in the coming months as we'll be participating in the Steel Bridge Competition and the Concrete Canoe Competition!
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