EXPERIMENTAL STRUCTURES ARCH-413-1
Professor Armando Plata
Thomas Frank
Jared Bilsak
ARCH
Terrell Ramrattan
Henry Thomas
Phil Luu
Edwin Figueroa
Brandon Lansing
EXPERIMENTAL STRUCTURES ARCH-413-1 Project Outline
ARCH FUNICULAR SHAPE OF AN ARCH
Relationship of height to width ratio and thrust force In 1965 the English scientist Robert Hooke (1653-1703) discovered the shape of an arch. He wrote his discovery “As hangs the flexible line, so but inverted will stand the rigid arch”. The arch and the hanging chain must be in equilibrium and the forces are simply reversed: since the chain can only carry tension, the arch therefore acts under compression. In 1748 Giovanni Poleni analyzed the safety of the cracked St. Peters dome in Rome using Hooke’s analogy. He showed the dome was safe by employing the hanging chain principle. He divided the dome into 32 unequal weights, and then sowed that the hanging chain could fit within the section of the arch and was therefore safe.
This exercise will investigate the relationship of tension and compression of a hanging chain and an arch. In addition, the thrust force at the support as it relates to its height. The dimensions of the constructed arch are as follows: Height: = 48” Span: = 96” The arch will be divided into 17 segments and the approximate size of the segments is 6” x 6” x 3” built of concrete (approximate weight = 9.4 lbs per segment)
EXPERIMENTAL STRUCTURES ARCH-413-1
ARCH
Process - Creating a grid To begin the process of designing an arch, we first hung chain from two points and outlined the shape that it fell at. We then constructed a 1”x1” grid around the chain to successfully develop a general outline of the shape of the arch for understanding and construction purposes.
Chain hung to generate the shape
Students laying out the 1”x1” grid
Students laying out the 1”x1” grid
Students laying out the 1”x1” grid
Students laying out the 1”x1” grid
EXPERIMENTAL STRUCTURES ARCH-413-1 Process - Developing stability (sketches and cad drawings)
ARCH To develop stability to the arch we decided to create a split at the third block from the ground. We experimented with angles of the split at decided that 30 degrees off center for each side (60 degrees total) was sufficient for stability and aesthetically pleasing.
Cad drawing exploring angles
Sketches showing ideas expressed in class
Sketches showing ideas expressed in class
EXPERIMENTAL STRUCTURES ARCH-413-1
ARCH
Study Model 3”=1’ We decided to construct a 3”=1’ model of the arch in MDF to grasp and understanding of how to construct the split in the arch at real scale. During the construction of the arch we realized that we needed exact angles in the split which led to the construction of the arch in the computer program Rhino. Despite needing the exact angles the arch performed well.
Above: the top section of arch modeled as 1 piece for convenience Below: The split of the arch being modeled before the curve is applied
Phil and Edmund measuring pieces of the arch
Above: One of the pieces that connects to the split before the curve of the arch is applied Left: The key piece in the split
EXPERIMENTAL STRUCTURES ARCH-413-1 Construction of a 3D Rhino Model (Plan, Elevation & Perspective) We developed the exact arch that we were trying to produce in pieces of concrete. This helped us determine exact angles on the key piece of the split. From here we began to construct the top, key, and base pieces as well as design a form-work for assembly.
Right: Perspective of the arch Bottom Right: Plan of the arch Below: Elevation of the arch
ARCH
EXPERIMENTAL STRUCTURES ARCH-413-1
ARCH
Form Work for Arch
Above- Block from formwork Below- Henry measuirng formwork
Below- Poured Concrete in Forms
Above- Poured Form Work Below- Multiole forms
Above- Key Kink Form Work Below- Key Kink Form Work
Below- Key Kink Form Poured
EXPERIMENTAL STRUCTURES ARCH-413-1 Form Work For Assembly
ARCH
EXPERIMENTAL STRUCTURES ARCH-413-1 Final Arch
ARCH