Prefabrication experiments - 112 - Structures - 3 - The Butler Frame

The production stages linking resources, materials, component manufacturing, structural systems and quality control underly the principles of Offsite construction and industrialized building systems. Simplified on-site assembly of pre-engineered components require a rational design, engineering and production process. Steel construction and frame structures have typified this relationship.

Steel frame construction is a straightforward assembly of hot or cold rolled structural profiles in assorted shapes and sizes. Each component is manufactured and catalogued and can readily generate skeletal structures that offer flexible planning and perform according to their engineering.  Steel construction has related to off the shelf assembly since the early 19^th century. Henry Robinson Palmer patented rolled corrugated iron in 1820, which became a staple of many dry construction kits exported to several British colonies.

In the vast field of steel construction, the Bulter rigid frame depicts steel's relationship to pre-engineering. Patented in the early 1940s by the Larkin brothers, owners of the Butler manufacturing company, the frame structure became the basis of the company's large line of engineered building kits. Their objective was to offer a manufactured hangar type building to supply a growing need for industrial structures.  Somewhere between a portal frame and a gable frame, a series of aligned frames composes a simple shelter. The pointed arch structure employs rigid connections at each junction reducing and countering beam deflexion associated with large span buildings.

The moment/rigid connections between column and rafter counter lateral loads and create an open space that could be organized in plan and section with little restrictions and without bracing. The chamfered vertical columns along with the chamfered rafters express material rationalization: a schematic of structural efficiency. Greater spans are achieved by simply increasing material sections.

The rigid frame is anchored to standard strip foundation walls. The streamlined shape is still available from Butler Manufacturing in various sizes and spans from 60 – 300 feet. A metal building insulated panel complements the easy to erect Butler frame kit. Engineered buildings remain popular within industrial and commercial applications, but rarely for any type of architectural use. The pre-engineered prototype offers high value as it is both pre-manufactured and pre-engineered optimizing a potential quick maneuver from product request to on-site assembly.

Butler Frame undergoing laboratory testing