polycarbonate/polyethylene- pyramidal modulesDimensions:
aluminum- connectors, casing, floor trusses
plywood- ladder ( ribbing), decking
rubber- weatherproof grommets at joints
pyramidal modules- 4' x 4' x 2'
ribs- 4'5" x 2"(to 1") x 4"(to 2")
each arched unit- 4'9" wide
floor truss- 2' deep, 1' off ground
overall height- 23'
overall length- 4'9" x 34 units = 157'
The design derives its strength from multiple small members combined in a continuous triangulated three-hinged arched system. Consistent with a Lamella Arch System, Renzo Piano provideds lateral stability witout the use of diagonal ties. Each bay consis ts of 12 4' x 4' x 2' transparent polycarbonate pyramids which form an arch. A secondary plywood arch joined to the pyramids at their apexes stabilize the form.
There are two crucial joints. At the base of the structure, a pinned connection attaches the arch to the exhibition floor decking. At the top of the arch, another keystone pinned connection joins the two quarter-circles together, creating a three-pinned arch.
Most vertical loads are introduced onto the structure in the form of hanging weight, such as the HVAC systems, lights and exhibits. The structure's primary function is to create a transparent enclosure for the IBM exhibit. The exhibit required continuou s space, unimpeded by structure. A promising response, the arched system directed vertical loads to the outer edges and offered flowing, unbroken and malleable space. It is not designed to hold much weight, however, the inherently strong form would be a ble to withstand great loading. The unyielding, triangulated forms of the quarter arches disallows any substantial deflection, making the simple, thin pinned connection at the center sufficient. There is no need for ribbing at this point. The pyramidal modules take both compression and tension. The lower planes of the modules are in compression, and the opposing planes are in tension, resultiong in a system which operates much as a regular truss. The floor system introduces a simple flat truss, which carris the major live loads of the structure, people, computers and displays.
Lateral Loads
As stated above, the structure relies on the principles of Lamella arch system, defined as a series of intersecting arches. Such a system precludes the necessity for any diagonal bracing.
Loads introduced longitudinal to the entire structure are resisted by the combination of many arched bays, which behave much like a barrel vault. Loads introduced against the archers otherwise are dispersed in the same manner as anticipated live loads ha nging from the structure. The extruded arch form provides an infinite number of parabolic paths through which forces can be carried to the decking underneath.
Joints connecting the arches to the deck are once again of crucial importance, as are the joints at the top of the arches. These joints and the numerous smaller connections between smaller units allow slight flexibility.
Interesting to note is the shape of the ribbing: each piece is molded to best resist buckling, identifying them as primarily compressive members.
what are some buildings that are appropriate to look at to further understand this building? this can be from spatial ordering concepts to structural types.....
Issac Boyd and David Ross
ARCH 461/561 Spring 1995
Do you have questions about adding a case? or a building to suggest??????? send a message to me....... chrisl@aaa.uoregon.edu