Prefabrication experiments - 265 - Connectors - 06 - Roger Halle's building system

Identified as a research architect, Roger Halle (1919-1993) was an American inventor / designer / architect who spent his career experimenting with building systems and components aimed at simplifying onsite construction and reduce construction costs. He patented connectors, processes and pieces, which all lead to the foundation of the Halle Building System Company. Based on the ideal of industrializing building, the heart of the Halle building system was a connector devised to streamline and normalize a three-axis assembly between vertical columns and horizontal beams. He conceived his connector as part of a catalogue of steel ready-made components leveraged toward a large number and variety of buildings. The open frame steel skeletal structure would also make the integration of other building systems straightforward with the use of open web joists for floors. The open joists’ web shapes a network of spaces for passing ductwork, plumbing and wiring. All standard structural components could be manufactured to stock and specified according to guidelines and design tables limiting complex engineering tasks. This would further streamline the building process. 

 

 Paralleling many of its contemporaneous experiments, the overall building system was dimensionally coordinated and arranged around a 40-inch modular grid matrix, which would define spans and all connecting components. The connector is a steel unit shaped with consoles to support horizontal joists and male extensions to connect vertical column sections. Once inserted into the lower and higher columns, bolting the joint ensures structural continuity. The joists are also fashioned with a fused seat that sits over the connector’s console to easily and precisely bolt it in place. Apertures on the unit’s two opposing directions optimizes its weight to stress ratio and also makes it possible to pass systems (wires or pipes) through the joint; making it a veritable cable chase. This simple matrix was designed to reduce the number of pieces required for a simple post and beam skeleton. Considering integration of all building systems, Halle also proposed a u-shaped lower and upper chord for the joists making it easier to attach floor or ceiling panels.  This universal connector designed for assembly could also in today’s jargon be designed for disassembly facilitating long-term adjustments and evolution. 

The Halle Joint

Prefabrication experiments - 264 - Connectors - 05 - Patch Project

Designing and creating underwrite making by federating a great deal of knowledge imparted by professional education, training or by specific guidelines and normalisation. The democratization of timber construction, in particular, communicates this collective sharing of artisans’ methods, cutting standards and normalized joinery. Industrialization substituted the artisan with task division, placed knowledge in the hands of engineers and manufacturers and made specialized components or pieces the core of modern building culture. The ensuing normalisation significantly diversified production. A quick walk in any hardware store in the connector aisle presents the innumerable amount of ready-made hangers, straps, fasteners and couplings for putting two pieces of timber together. While removing the specialized artisan, these factory-made fasteners also make it possible for untrained users build their own structures with the confidence that the connector is robust and sturdy enough for its intended use. The connector fashioned with the correct dimensions, thickness and angles simplify joinery and have long contributed to the D-I-Y building and the recent hacking culture. Producing a connector that is both simple to use and understand in a sense elevates its designer’s status to craftsman as the device’s use in multiple structures showcases inherited purposes and potentials for customizable assemblies.

 

Patch Project by the Polish design studio Beza Projekt continues the tradition of the Do- it-yourself well-designed connector by streamlining making and providing anyone the means to craft their own projects. Patch Project showcases the designer at once as the developer and the artisan for crowd sourced productions. A series of bright red plates folded and shaped into different configurations offer a number of varying ways of joining standardized pieces of timber. Analogous to Ken Isaac’s modular matrix structures developed in the 1970s, the connectors are the basis of a perceived variety established on predetermined options for geometric adaptations. In Patch Project the connectors are meant to symbolize a type of conceptual patchwork arrangement with encoded yet unspecified directions. Each timber piece can be placed at right angles or at predetermined angles for both ordered and chaotic arrangements. This type of connector is a special architectural object as it imparts building knowledge and makes construction a fundamentally social process connecting design, craft and people.

Patch Project connectors' series

Prefabrication experiments - 263 - Connectors - 04 - Geodesic dome hubs

First explored in the 1940s, every generation of educators, architects, designers and DIYers seems to rediscover the pleasure and structural enlightenment that comes from assembling a geodesic dome. Associated with R. Buckminster Fuller and his Fuller Research Foundation, the geodesic dome is a segmented reticulated framework, which forms a spherical shape. Established from the study of an icosahedron, a platonic solid of twenty identical equilateral triangle faces, points (vertices) are extended outward toward a great circle according to a predetermined number of divisions or segments. This division of each composing triangular face is the dome’s frequency or its capacity to approach the sphere’s radius as closely (greater frequency) or as loosely (lower frequency) as desired. 

 

It seems at first glance relatively simple as the segments follow a repeating pattern. This is the case for the equilateral triangles, however each segment and angular deformation within the triangle are dimensionally nuanced and modulated as they spread toward the curve. The hubs, intersections or connector points are fundamental to the dome’s assembly as they define at once the angle and the number of struts splitting from each vertex. Connectors are the secret to the domes’ perceived simplicity. Along with their numerical and mathematical importance to the domes’ geometry, structurally the hubs react to both tensile (parallel, hoop) and compressive (meridional, arch) stresses. Composing triangles and their connection points push and pull against one another, under uniform loading. 

 

Sonostar connectors, is one of many companies offering options to construct a dome based on a configuration that is determined on-line through the company’s website. A construction kit of parts from made to stock pieces and connectors is then delivered to any context. Connectors include five or six appendages regardless of the dome’s frequency as combining the triangles forms a skeletal network of hexagons (6 points) or pentagons (5 points). Geodesic domes are experimental structures, rarely massively applied, that garner fascination through the satisfaction that comes with seeing geometry and structural assembly in action. Sonostar’s dome kits propose standard PVC piping for the struts, which makes for a simple female to male fastened or bonded connection.

Two connector scales (standard and mega hub) form the company website

Prefabrication experiments - 262 - Connectors - 03 - Charles Attwood, Unistrut and Moduspan

The successful application of steel in building structures has paralleled and entrenched standardization. The normalization of profiles, shapes, pieces and fittings was rigorously controlled from the factory to the field. Pre-established and calculated connections facilitated steel’s democratization by sharing validated models for engineering, architectural design and construction. The steel building construction sector developed an open exchange of fabrication, specifications and assembly standards. Further, this knowledge was certified in the factory and by academia supporting the use of published computations and theory. Industrialists imagined all manner of skeletal and reticulated building structures from the cataloguing of parts and assemblies. 

 

One of the most enduring systems, the Unistrut building component system was based on both standardized shapes and simple bolted joinery for securing pieces together in a plurality of directions and arrangements.  Charles Attwood created Unistrut in the early 1920s for mounting electrical components in equipment, racking or scaffolding applications. A spring-activated nut that is pushed and glided in a u-shaped profile is the central proprietary element. The nut is positioned along struts at any point and makes multiple arrangements possible. Expanded further, the Unistrut system went from a simple strut and tie structure to a reticulated 3d space frame with the addition and invention of a mulit-directional hub connector. 

 

Known as Moduspan, a subsidiary system of the Unistrut corporation, it employed a simple plate-based joining system for fastening a structural framework of upper, lower and diagonal chord members. The horizontal and vertical plates clipped together maintain an x,y,z coordinated system for coordinating anchor points. The standard Unistrut channels 40mm x 400mm could be bolted to the plates at different locations to vary length, angle and overall geometry. Applicable to floor and roof construction, as an open treillis, a type of three-dimensional truss, it was just one of many space frame prototypes (Mero, Triodetics, Abstracta) invented in the second half of the 20th century. Attwood marketed the no welding or drilling, flexible and adaptable business model from the early 1900s and it is still applied today. Moreover, the Unistrut and Moduspan design for assembly principle could today be reversed and speak to a design for disassembly model making all components part of systems with multiple service lives.

Moduspan connector

Prefabrication experiments - 261 - Connectors - 02 - Abstracta building system

 

Transferring know-how from object, product or commodity production to large-scale building construction has motivated a spectrum of potential building systems both in theory and in practice. Volumetric modular stacking as an approach to industrialized building has been compared to modular toy assembly sets. Toys, from Lego blocks to Lincoln Logs and the infamous Erector Set, were cited as procedural models for simplifying onsite assembly. Modular kits composed of controlled, standardized and compatible parts, still fairly marginal in building, have been successfully applied in furniture assembly. Elements are categorized, bundled and packaged according to predetermined formal or functional objectives. 

 

Scaling the modular kit from furniture to building was at the core of Poul Cadovius’ Abstracta reticulated structural frame system. The Danish born inventor, designer and producer conceived the system in the late 1950s and filed for a patent in 1964. The Abstracta system is composed of a formed cast steel connector joint with a varying number of specially profiled appendages ending in a spherical bulge that fits and locks into tubular struts of varying lengths. The connectors are designed on the same principle as Cadovius’ modular furniture kit with one key difference: the size and thickness of the tubular struts have a minimum diameter of 45mm and a wall thickness of 3mm. The straight member spokes are manufactured with an internal globular pocket for the connector spigot, lodging it in place and resisting compression and tension. The same connector and struts can be assembled into 3d structural matrices to make exhibit structures, scaffolding or even large scale dome and freeform structures.

 

The Abstracta system was awarded the Gold medal in 1961 at the International Inventor’s Congress in Brussels. Its application in building remained negligible. Casting a connector with varying limbs both in terms of spigot angles and a specific shape demands production processes and tolerances that have not been the norm in building construction. Further, the design of hub connectors in general architectural systems has not tackled requirements to coordinate systems other than structure and it is difficult to imagine one connector capable of attaining such universality. Cadovius’ Abstracta system’s ongoing application in furniture still inspires the longstanding intention of assembling architecture with the simplicity of a toy. 

Patent drawing for the connector

Prefabrication experiments - 260 - Connectors - 01 - The Universal Building Joint

Architecture and construction in their basic essence are related to joining. Connecting, linking, aligning and fitting materials together require knowledge of both crafting and detailing. Joinery reveals how architecture is made. The modern architect streamlined design and construction through systematized thinking translated into translatable and intelligible building assemblies. Factory production made detailing into a language for the architect to showcase how to build through drawings and specifications. The search for the universal connector was an underlying theme of the modern architect’s new role of detailing construction.

 

The most cited and prominent example of this ideological vision of a multifunctional building joint leveraged toward multiple patterns is the General Panel House connector created by Walter Gropius and Konrad Wachsmann in 1941. The heart of the modular panel house system, the pluri-directional surface connector, was developed to join panel edges horizontally and vertically to arrange an infinite number of dimensionally coordinated variations. Inspired by his training as a cabinetmaker and as chief designer for the Christof and Unmack timber house producer, Wachsmann devised a steel biscuit joint precisely shaped and connected through a plate and wedge system. The plates were cut and shaped to match-up with the precision of a lock mechanism.  The hook-type metal clips would be kept in a latched and locked position by a compression steel plate wedge inserted through the panel’s thickness attaching panel and joint. Modular stressed skin panels and planning modules were outlined by what at the time had become the standard for material coordination: 4-inch module and 40-inch grid. The connectors were positioned according to the grid creating a repeated stitch pattern. 

 

The General Panel Corporation set up in a repurposed aircraft factory was to be highly automated and influenced by the era’s highest production standards. In 1984 Gilbert Herbert recounted the story of the General Panel Corporation in his book The Dream of the Factory Made House and cited many reasons for the company’s failure to attain what Wachsmann had promised. 

 

Architecture’s and architects’ fascination with joinery is still an obsession throughout the discipline and the quest for a universal connector is the theme of the next 10 blog posts which will present a number of connectors designed to attain a universally applicable joint.

The universal connector

Prefabrication experiments - 259 - Operation Breakthrough - 10 - Descon-Concordia's forward looking platform architecture

Design for manufacturing and assembly (DfMA) or the concept of product architecture, already applied in various industries, have been put forward as strategies for applying the same methodologies to building production. Kieran and Timberlake’s manifesto (Refabricating architecture, 2004) and an abundance of literature since the publication seem to point to modularization, design platforms, and offsite fabrication as outlets for lean production.  A recent example of this ideology explored by Bryden Wood, Platforms Bridging the Gap Between Construction and Manufacturing, develops similar notions including virtual modeling and prototyping and data harvesting to streamline the building process. 

 

Even as platforms are being identified as ground-breaking, theories for increasing productivity and product architectures are not new concepts. Perhaps terminology has evolved but the type of systemic breakdown of a project’s components and logistics were central to Operation Breakthrough. Proposals were truly innovative in this regard as many were based on comprehensive logistical frameworks similar to what has been recently titled a building platform approach to DfMA (pDfMA). 

 

One specific example and the only foreign project approved for US construction was the Descon-Concordia panel system. The sophisticated management plan included an open structural system of reinforced concrete factory-produced prestressed modular panels. From two storey to twenty-two storey high collective dwelling units, panels would be prepared in accordance to specific structural criteria while all other elements were to be shared between different designs and scales. Large reinforced concrete panels, off-the shelf components and mechanical sub-assemblies were part of the overall modular ideology shared between collaborating partners. This collective modular and dimensional coordination created an environment for manufacturers to produce all required elements concurrently for different sites, increasing production and productivity. Five modular panels for walls and four panels for ceilings made up the essential building blocks for a large number of designs. The proposer defined their system as a flexible management system and building kit : a type of product platform for reforming construction’s lagging challenges. Descon-Concordia, a consortium from Montréal, Canada was arguably the most advanced, forward-looking system in Operation Breakthrough and would certainly still be considered as a great innovation today in matters of applying factory production to building construction. 

Descon-Concordia building components and management system

Prefabrication experiments - 258 - Operation Breakthrough - 09 - Pemtom's three-dimensional housing matrix

 

Mat modular housing is a longstanding idealized experiment in planning spatial and geometric relationships for dwellings. The regulating grid unites housing dimensions, criteria and collective dynamics with standardized production parameters. A dwelling field, clusters expanded horizontally and vertically could be programmed for low, mid and high-density patterns. Further, the volumetric tessellation could be mapped over any topography and setting as each unit is a type of generic kernel.  

 

The Pemtom group’s proposal for Operation Breakthrough represents still another view of this highly peddled architectural experiment. Each factory-produced volume would be composed of walls, roofs, and floors, outlined by a rigorous grid module, 13’ (3.9meters) x 13’ (3.9meters) x 9’ (2.7 meters) and constructed from stressed-skin panels. The structural insulated panels (SIPs) of stressed skin construction employed the same composite structure, a laminate of plywood layers and an insulating urethane core, as the panels that had been previously been studied by the US Forest Service as far back as 1937. Pemtom’s proposal references USFS research.

 

Nine juxtaposed, stacked and aligned building blocks would be required to organize a 1500 square-foot three-bedroom dwelling. Each volume was programmed for particular dwelling functions, rooms and living spaces, while more mechanically complex designs could be used for bathrooms, kitchens or service cores. 12 spatial units were provided in the proposal as a catalogue of composing parts.  The sections attached to one another formed a uniform structure with a few composing parts. The clustered volumes or boxes would be mass-produced and their on-site juxtaposition streamlined up to fifteen stories high within a concrete or steel cradle or mega-structure. As described and illustrated, the three-dimensional grid regulates of every part of the building system without any evident hierarchy or separation of the public, private or common areas.

 

Pushed in many forms, this type of normalized housing has been largely opposed by market forces perhaps because architects and manufactures never provided for the conceptual interfaces between architecture, production and individual habitability. Pemtom’s proposal foreshadowed current information based experiments and DfMA approaches where building platforms are delineated by and limited to a controllable quantity of customizable options in a scalable housing system.

Pemtom's catalogue of parts

Prefabrication experiments - 257 - Operation Breakthrough - 08 - Birdair and Poly Petro Chem - inflatable forms

The most noteworthy aspect of Operation Breakthrough is the amount of partnerships formed to respond to the challenges of construction’s lacking productivity and reinvent industrialized building. This reinforced George Romney’s affection for cooperative capitalism and cross-pollinating stakeholders. The result, leveraging the construction industry and its composing partners toward an open source sharing of strategies - a catalogue of construction techniques - could be an example to today’s still lagging construction industry. Expressly within the framework of identifying affordable housing systems, Operation Breakthrough provided a space and platform for presenting well-known as well as more marginal systems, materials and methods. A prime example of an inventive industrial partnership was provided by the consortium identified as Housing Advocates composed of Birdair (a tensile structure producer) and Poly Petro chem (a plastic producer). Both companies came together to imagine a building system and process articulated to their specific areas of expertise. 

 

Birdair is well known for their tensile structures.  The company’s foray into inflatable and reusable concrete formwork leading to the publication of a patent (US723751A) was the main element of their proposal. The idea is to employ Birdair’s knowledge of inflatable tensile structures to produce an inflatable, fill it with enough pressured air to shape a compressive geometry and its structural formwork. Fluid material could then be poured or cast onto the inflatable and left to set and cure. Once cured the reusable formwork could be deflated, removed and set-up to cast other structures. For Operation Breakthrough, the on-site concrete was replaced by a material identified as Carbalon; a two-part urethane compound sprayed, or cast onto any mold. This material would be hardened over Birdair’s reusable and inflated forms to shape exterior walls, and interior walls, while service cores and other required components would be produced by third party partnering manufacturers. 

 

The inflatable forms would be anchored in place by strapping the tensile structure over a foundation. Door and window openings, part of the casting mold, would also be positioned in place while casting the material and allowing it to cure into a monolithic structure, which could then be finished in a variety of ways from traditional siding to stuccoing. Along with the casting controlled on-site with portable equipment, the pneumatic formwork creates a site intensive industrialized construction process. 

Sketch of the Housing Advocates proposal

Prefabrication experiments - 256 - Operation Breakthrough - 07 - Christian Frey's Universal Building Rib

Architect, inventor and founder of Suspended Structures inc, Christian Frey represents a particular type of industrialist, that from generation to generation sees industrialisation as the way out of lagging productivity issues for construction and for developing affordable housing. Involved in research and in expanding his own visions and building systems, Frey’s most ambitious project is arguably his patent for modular dwellings suspended from a central core. Published in 1967, Frey’s patent, Suspended Module Buildings(US52323465A) proposed a central mast from which cables carried gallow-like cantilevered beams onto which any dwelling unit could be assembled. This class of open systems has been studied and explored in various formats and share the idea of a collective infrastructure with unrestricted floor areas for individualized housing. 

 

For Operation Breakthrough, Frey’s proposal is a toned down version of the patent; what remains is the idea of a sequence of suspended platforms. The rectangular floor surfaces attached to the structural core organize the open framework. Each floor panel structure would be assembled from open web joists to form lightweight slabs cantilevered from and attached to vertical columns. The floor panel loads are carried to transverse rib beams connected to vertical columns. Together, the horizontal frames, rib beams and vertical columns form what the inventor identified as an «URB» Universal Building Rib. The «URB» planning module could be aligned, juxtaposed, stacked to create a spatial variety acquiescing any individualized interior arrangement. 

 

The floor pallets and their open webs and grids connect to vertical ducts for distributing wiring, pipes and ductwork. The unobstructed vertical and horizontal network idealize a dynamic framework expandable in every direction and planned for large scale and small-scale dwelling aggregations. Separating and layering structure and interior organization follows the «open building» tenets. This essence of open systems continues to illustrate the conceptual distance between architectural designed industrialisation and the requirements of manufactured building. This archetype of fixed infrastructure and variable infill does not respond to manufacturing constraints of modular building, it is merely a structural concept. Further it doesn’t address the architectural singularity sought by many architects. Like many of its contemporary open systems, this architect’s dream and obsession gained little traction in industry and in architecture. 

Universal Building Rib and patent section (extreme right)

Prefabrication experiments - 255 - Operation Breakthrough - 06 - Optor Corporation

Organized in the late 1960s, it is unclear how much influence, if any, the building experiments undertaken in the Man and his World (Expo 67, Montreal, Canada in 1967) universal exhibition had on Operation Breakthrough’s proposals and processes. Moshe Safdie and August Komendant, architect and designer of Habitat 67 surely inspired a generation of architects through their vision of housing and construction’s industrialization. Many proposals conceived for Operation Breakthrough argued for similar concepts, pushing the idea of modular boxes, stacked, amassed, clustered or juxtaposed to breed new housing patterns. 

 

Exhibition pavilions have long informed and guided architectural advancements and Expo 67 included many accounts of formidable structural units deployed in multiform varieties. The lineage from exhibit structure to inhabitable space frame was also displayed in metabolism experiments. This theme is also evident in one particular proposal for Operation Breakthrough.  The Optor Corporation project, designed and developed in Montréal, offers a glimpse into potential cross contamination between exhibit structures and housing. The space frame structure of inhabitable tetrahedrons assembled from tubes and hubs defined an open structural concept divided or enclosed by stressed skin panels, service walls or functional units. The support and infill strategy would be easily assembled and as simply disassembled stacked, packed and redeployed for other sites. 

 

The slotted aluminum hub fasteners secured flattened tubular ends slipped into the cylindrical hub’s grooves in a similar fashion to the already well-known Triodetic connector used for many exhibit buildings (see blog post 149). The exact source of Optor Corporation’s design is an architectural mystery. A clue for further investigation may be found in an article that appeared in the ABC journal (Architecture Bâtiment Construction) in may 1968. Author and architect Étienne Dusart described a space frame building system that in all respects seems to be the ideological basis for the Optor system. The author describes the same basic framework and stressed skin fiberglass panels. Sprawling horizontally and vertically the space structure would shape a new type of urban structure that could theoretically grow in every direction as a structured geometric trellis.  Both systems also share the basic triangulated support system and functional units delineating a multiplicity of infilled dwelling patterns. 

Images above : Article from ABC journal ; Image below : Optor proposal

Prefabrication experiments - 254 - Operation Breakthrough - 05 - Commodore Corporation and stacking mobile homes

A mainstream example of the modular, manufactured or mobile home builder’s business model, the Commodore Corporation along with its subsidiaries and partners has been manufacturing affordable housing since the early 1950s. Their segment, the mobile home, although somewhat marginal, represents the successful application of industrialisation to construction. The integrated process harmonizes design, manufacturing and procurement supply chains adjusted to assemble a number of predetermined housing patterns. This combined design and delivery process applied to single-family dwellings relies on a standardized pattern book of models to circumscribe supply chain management, regulatory approvals, quality control, timeline and cost structure while reducing onsite construction risks.

 

This straightforward business model was tweaked in Commodore Corporation’s proposal for Operation Breakthrough. Along with a number of design firms, manufacturers, research and code specialists the company proposed a reinforced concrete megastructure assembled from «precast» or «prestressed» components for high-density frameworks, steel components for medium-density frameworks, and timber for low-density frameworks. These structural skeletons would carry stacked modular volumetric boxes using Commodore’s established process. Idealized as a simple switch from individualized dwellings to collective dwellings the company would mass-produce up to 30 000 units per year. 

 

The superstructure grid, defined by a 14-foot square horizontal module and a 11-foot vertical module, was dimensioned for fitting normalized 12’ wide, 10’ high and from 44’ to 60’ long modular units. The simplicity with which the system was illustrated displays the long-standing disconnect between dwelling manufacturing and collective housing construction. Interfaces between units were simply omitted or neglected. This simple stacking rhetoric avoided the necessary on site joinery and stitching, which must be detailed and optimized with the same quality control rigor associated with the factory to circumvent onsite entanglements. 

 

The Commodore Corporation would oversee marketing, design, procurement, construction management, module delivery and assembly. This comprehensive building model seems ideal. However the necessary parameters and criteria that come along with collective housing, the correct and robust detailing of sound control or fire control, have been replaced by simple stacking. Omitting interfaces and promoting one-dimensional stacking continues to haunt modular construction. Holistic systemic criteria must be included in project design. If not any real advantages of off site construction are quickly lost. 

Proposal rendering - modules inserted into a load-bearing framework

Prefabrication experiments - 253 - Operation Breakthrough - 04 - Spun Plastic Domes

The vast majority of Operation Breakthrough proposals identified some category of modular construction to solve construction’s lagging productivity. Boxes or panels assembled into clusters of medium to high-density housing organizations would offer affordable solutions. The manufactured systems would arrive on site and simply be assembled reforming traditional construction processes. Less prominent, but equally important proposals offered unfamiliar materials, models or strategies detached form conventional prefabrication approaches. One of the more intriguing and eccentric proposals from DOW Corporation, the Spun Plastic Domes, calls to mind the singular dwelling visions associated with Buckminster Fuller’s Wichita house patented some years earlier. 

 

Dow’s polygonal dwelling unit would be assembled from vertical panel service walls that formed a lightweight but deep exterior wall. The wall’s depth included integrated built-in furniture or storage. This useful thickness circumscribed interior space in a served versus service space configuration. The segmented deep structural skin, one to two stories high, supported a half-sphere dome cap. A thin shell cupola rested on panels built from conventional wood stud framing. The dome’s composition was shaped on site. An extruded polystyrene insulating core was sprayed over a metallic framework grid attached to the fiberglass reinforced exterior shell’s intrados. The dome’s interior would then be sprayed with a decorative plastic coating to produce a harmonized interior surface. Each dome covering included a central oculus for lighting and ventilation further rendering its lineage to Fuller’s Dymaxion Unit.

 

Although the dome was the proposal’s flagship element, the envelope service pieces were the innovative idea as they argued for a multi-functional exterior wall. Designed as modular segments, the rounded plan could be individually planned, mixed and matched according to varying uses and compositions. Housing clusters included multiple configurations all articulated to a grid of service distribution points radiating in multiple directions. This service matrix was designed as a field over which the circular dwellings were moored. Anchored by earthwork and foundations to the collective infrastructure and service matrix, the center of each unit was positioned over the service point by a vertical circulation stack that connects lower spaces with upper living spaces. The panel service core would be customized in the factory to include plumbing, electrical systems or any other mechanical device.

Dome dwellings rendering

Prefabrication experiments - 252 - Operation Breakthrough - 03 - Dano Modules - on site megastructure

The vertical stacking of modular volumetric boxes in multiple configurations forms a common thread of many high-rise proposals in Operation Breakthrough. Piling, clustering and juxtaposing ready-made factory produced boxes was considered as a simple building block strategy for affordable housing. Each proposal in its own way tries to underscore this simplicity while offering various strategies for structuring the necessary, sometimes complex, cost intensive and redundant secondary support structure which makes it possible to stack identical volumes. From megastructures to prestressed skeletons, carrying individualized stacked units is one of the challenges of volumetric modularization. 

 

Dano-Modules, a precast producer from Chicago Illinois addressed the support structure in a most innovative way. Each profiled volume was designed as the formwork of an on-site cast superstructure. Defined as the building’s «hardware», each concrete cast unit with a modular dimension of 8 ft (2.4 m) x 12 ft (3.5 m) was based on standardized spatial/room arrangements and regulated transportation limits. The basic container would be easily delivered by truck from the factory to the building site. Interiors «software» could be adapted to any use and determined by the end-user. 

 

Two 6x8-inch (150x200mm) rib-like perimeter beams were factory-cast in the 12-foot direction of each unit’s face. When stacked or juxtaposed, the aligned ribs created a type of mega-Vierendeel space frame, a network of open spaces or chases for running mechanical equipment, plumbing, ductwork or wiring. The open chase also determined voids for the on-site casting of reinforced concrete. When filled with steel reinforcement and concrete, the monolithic structure braced the boxes horizontally and vertically and secured all components in place. Before being filled with concrete, certain voids would be pinpointed for prefabricated mechanical racks distributing services vertically or horizontally. Cited as an advantage, the reinforced concrete megastructure would save 50% of the required formwork when compared to conventional construction. Once cast in place, 16 inches (400mm) - 20 inches (500mm) of concrete would separate each unit. 

 

Certainly innovative in its construction, technology outperformed architectural design criteria as the Dano-modules linear organization created a standard and monotonous double-sided planning module with living spaces on one side and sleeping spaces on the other. Further, the massive concrete megastructure would definitely impede any changes or time-based evolution of the structure. 

Dano module stacking creating a vast formwork

 

Prefabrication experiments - 251 - Operation Breakthrough - 02 - Alcoa's Tension Frame Structure

Although Operation Breakthrough did not radically change the way housing was built in the USA, its enduring legacy as an exercise in industrial collaboration is underscored by the amount and variety of corporate consortiums that proposed housing systems, procurement options and integrated supply chains. George Romney, owing to his background as an industrial lobbyist was able to federate his brand of «cooperative capitalism» evident in partnerships that resemble industrial clusters. Emphasized in a proposal by Alcoa, the Aluminium Company of America, the list of affiliate companies included partners ordinarily portraying a fragmented building industry, however they were brought together to develop a horizontally and vertically integrated business model for a three-tier housing scheme for low-density, medium density and high density through 12 different building possibilities. 

 

Mass-produced service cores and storage wall modules were common to the twelve systems. Each process type displayed a particular approach to cost and product optimization with basic component sharing and modular coordination. Eleven systems in Alcoa’s proposal were conventional interpretations of either panelized or componentized parts over steel or reinforced concrete skeletons.  The most ambitious plan was Alcoa’s tension-framed high-rise system composed of steel mega-trusses cantilevered from a concrete core. Illustrated in the image below in a historic downtown core, it symbolizes the type of a-contextual, technology at all costs, consenting high modern ideologies seen in a majority of Operation Breakthrough’s proposals.

 

The 10-30 story structure’s plan was determined by vertical circulation and mechanical ducts rising with a reinforced concrete core.  Steel cantilevered trusses formed the gallows of this tower-crane building. Cables attached to the mega-cross beams would simplify raising manufactured volumetric dwelling capsules into place. Each volume suspended from the central core could be recessed or cantilevered horizontally or vertically over its neighbouring unit varying the exterior massing.  The reinforced concrete and steel lift literally hung dwelling modules in order to avoid the usual structural constraints associated with stacking and reinforcing individual modular boxes. Edge framed in steel or aluminium, the dwelling units would be completed in a factory and the proposal’s proponents argued that less staging areas would be required on-site making this mega-structure particularly well-suited for dense urban environments. 

Alcoa's Tension Frame Structure illustrated in context and in action

Prefabrication experiments - 250 - Operation Breakthrough - 01 - George Romney

  

Protagonists have had a significant and advocating role in the history of prefabrication. The storied narrative of off-site construction is full of operatives, often coming from parallel industries to architecture and understanding the prospects for increasing productivity in a long-stagnating construction sector. By federating politics, funds and trade associations, industry leaders have been central to channelling romanticized transformations in the construction industry. 

 

The following ten blog posts will look into several selected proposals for Operation Breakthrough (1969), established by the department of Housing and Urban Development as an initiative synchronized with the Fair Housing Act, a framework for affordable housing and its desegregation in America. The main proponent of Operation Breakthrough, George Romney, embodied the posture of an industrial operative encouraging new materials, methods and opportunities for increased efficiencies and productivity in bringing about low-cost housing for all. 

 

From lobbying for Alcoa and aluminum, steering the Automotive Committee for Air Defense or being named Chief Executive of American Motors, George Romney was well versed in manufacturing potentials and parameters. After being nominated by Richard Nixon as Secretary of Housing and Urban Development, Romney initiated one of the largest industrial based cooperative efforts to stimulate new ideas for affordable housing. Linked to his experience as a lobbyist, Romney challenged builders, manufactures and professionals to come up with efficient factory produced building systems. Although none of the proposals were massively produced or built, the program did succeed in showcasing the potential for cross-pollination between industry players. 

 

From over a hundred proposals, 22 systems and eleven test sites were set up to build and showcase prototypes. From conventional to utopian and fascinating proposals Operation Breakthrough highlighted the type of cooperative capitalism that Romney preached for and is underscored by the consortiums set up to achieve each integrated application. At once Inspired by and critical of building programs in post-war Japan and Europe, the program encouraged streamlined procurement, centralized design, mass-production along with the concept of open systems to achieve product variety based on component repetition. Not just another failure in the history of industrialized architecture, some of the proposals were perhaps too innovative for the American public who had comfortably settled in the timber platform frame as the reflection of their basic on-site construction culture of building.

Operation Breakthrough test sites

Prefabrication experiments - 249 - measuring devices - 10 - NENK modular planning grid and floor system

Through funding of infrastructure, large-scale building programs or housing construction stimulus, governments sustain crucial economic and social industrial sectors, especially during periods of crisis. The post World War II building programs in industrialized nations affected and distressed by years of conflict epitomize how governments braced and maintained economies while preserving specific types of production in the event of other conflicts. Optimizing construction, increasing productivity, applying military efficiencies and lessons to modern building are just a few topics that underscored government programs. 

Housing policies provided a framework for monitoring the building industry, highlighted areas that offered opportunities for productive change and mandated building and resource agencies to ensure building construction would benefit from technological advances. The Directorate General of Research and Development at the Ministry of Public Buildings and Works in the United Kingdom in the early 1960s would express this industrial advisory role through their sponsorship of one of the era’s most detailed, flexible and adaptable modular building systems. The NENK system was named after David Nenk, an architect who had been in charge of the Architects and Buildings branch of the Ministry.

The modular steel-framed skeletal kit integrated efficient steel component production within a reticulated geometric lightweight floor system. Assembled from repetitive and lightweight tubes and struts, the floor structure is ultimately a large spanning (36-foot (12m x 12m)) planning grid. Parts are multiplied, aligned and patterned to outline any space.  The basic unit is a 4-foot (1.2 m) inverted pentahedron, a square-based pyramid with a 16 foot-square area (1.44 m²). Placed and lined up on their apexes the bolted square-bases frame the floor grid, while the 2-foot (600mm) height from apex to base structures an open network of webs for passing ductwork, piping or wiring. Tie rods link all the pyramid tips shaping a rigid three-dimensional space frame. The four-foot planning grid was designed for varied column positions: centered on the apex, on each of the base’s vertex corners or at an edge’s mid point, this variability increased the number of design variables. First used to construct army barracks in the 1960s the grid system could be deployed for any use.

Nenk's assembled pentahedron floor modules 

Prefabrication experiments - 248 - measuring devices – 09 – Aircrafts and the Wonder Arch

Proportions and exact units for composing, measuring or coordinating architecture and building systems are normally articulated to functional requirements for fitting or harmonizing shapes, pieces or furnishings. These elements outline part-to-whole dimensions while determining standards, patterns and types over time. While not an explicitly categorized unit of measure, large spans serving the three military branches, army, navy, air force, in a way charted structural geometries as a function of wingspans, ship building sizes or spaces for armoury protection.   

Aircraft wingspan, above all, shaped architectural exploration and engineering invention to achieve the required open and free spans while reducing component and building dead loads. Konrad Wachsmann, Buckminster Fuller and Pier Luigi Nervi’s work underscored how military requirements influenced modern architectural and structural forms, specifically in the understanding of space frames, domes and form resistant structural shapes. All three inventors explored spanning large distances using reticulated structures made from prefabricated, manageable and arithmetically coordinated parts. 

Industrial development was an equally influencing factor in devising pre-calculated and prefabricated kits for large-spanning hangars or sheds. Manufactured for various storage needs, the steel barrel vaulted Wonder Buildings made use of their permanent versatile arched systems to invent formwork for a large-scale bomb-proof air-craft hangar. The wonder building’s semi-circular barrel vault is a compressive shape that reduces tensile forces and makes use of corrugations to offset potential localized buckling within the vault’s thickness. The undulated shape performs like a folded plate while its overall transversal curvature is basically a parabolic shell, which reduces horizontal thrust and bending through vertical rise. 

Known as the «Wonder Arch», the framework is made from transportable corrugated steel rib strips that are juxtaposed and aligned to create the half-cylinder hangar plan. Each narrow width curvature is composed of 9 identical steel panel voussoirs (circular segments) affixed in a semi-circular pattern.  The structural arched ribs are then bolted to the adjacent ones in a longitudinal pattern tailored to any length. Once fixed together, the building system is complete and could be used as is as a type of Quonset hangar. The Wonder Arch, however, was designed as permanent formwork. 500mm of reinforced concrete was poured in a perpendicular corrugated pattern over the vault to create a reinforcing trellis and make it bomb proof.  The Wonder arch was deployed during the Vietnam War and was a formidable structural achievement in bomb resistant shell structures. 

Wonder Arch ribbed section

Prefabrication experiments - 247 - measuring devices – 08 – Le Corbusier’s Modulor

Equally applied in traditional architecture and construction or via the invention of new manufacturing methods, standardizing and unifying measuring units and formulae make it easier to share knowledge about building or determining dimensional or functional requirements. Classifying ergonomic principles and their factorization into larger or smaller parts is the basis of architectural composition. The golden section “rectangle d’OR” is the prime example of a mathematical premise employed for the analysis of classical architecture and its geometric harmonic relations. The golden ratio (1 : 1.618) can be observed multiplied or divided into regulating proportions for decorative elements, overall building dimensions as well as structural proportions. 

Associated with refuting ornament and classical composition, these underlying geometric and numeric themes were hidden within modern architecture’s dogmas. Replaced and inspired by production standards, modernists concealed their classical penchants for the same Palladian ideal shapes and plans behind their new regulating orders. Sometimes these principles were derived from traditional architecture, such as Schindler’s use of the Japanese tatami or the Ken. 

Perhaps the most famous modern unit of measure, Le Corbusier’s Modulor (Module + Or) was specifically articulated to the concept of standardizing industrial processes to conceive architectural spaces that would be easily produced by modern methods. Based on his idealized understanding of human form which he deconstructed according to the golden ratio determining his basic sets of human to space configurations. The 226 cm height of the ideal man with his hand stretched out standardized floor to ceiling dimensions for a regular room or space. This 226 cm height was a multiple of the 1 to 1.618 golden ratio and exposed the architect’s perplexing relationship with classical proportions and themes.  Divided into multiples or different scales for directing a logical sequence to each particular design, the Modulor was for the iconic modern architect a type of slide-rule for encoded design skilfulness. Le Corbusier himself wrote about the Modulor in modest and humble terms. It was a tool for designing without having to refer or think about dimensioning. The Modulor allowed good design and its standardisation to be achieved efficiently; sitting, leaning, standing, stretching and all interrelated human activities defined by a harmonic measuring device. 

Le Corbusier's Modulor

Prefabrication experiments - 246 - measuring devices – 07 – Gridded measurement system for construction materials

Measurement tools and principles in architecture and construction invoke both the patrician idea of classical proportioning and all manner of tricks of the trade to help in anchoring or positioning building components and elements. Particularly within the spectrum of do-it-yourself aids, many geometric overlays and templates exist to simplify calculations and assembly of premade pieces. The 4x8 modular sheet is one specific example determining building dimensions and their constituting units. Modular production of building products is the basis for categorizing layers or systems and to ensure that components fit together in a rational manner. 

A gamut of apparatuses, hangers, supports, pegs are available in any hardware store. These anchors of every size and shape are precisely profiled to the dimensions and thicknesses of components such as joists and studs to standardize their joinery. Industrialized connectors pre-dimensioned according to materials have made the light timber frame the system of choice for do-it-yourself builders. 

Further experiments have followed elementary dimensional standardization to imprint materials with notes, grids and cut-lines to reduce on-site estimations and increase precision. A patented system by inventor Glenn Robell (US Patent US5673489A) proposed that all types of surface and sheet materials used in construction, from sheetrock to plywood and cement panels, be manufactured with a graphic veneer which inscribed onto the material surface a system for measuring. In a sense this gridded measurement system would be equivalent to adhering a large piece of graph paper over the material. This grid could include any number of measurement scales and notations to inform users of elements to avoid, such as nailing to close to edges or other constraints and care taking measures. The information could normalized and conform with structural or even code requirements. A simple example: bold lines could represent structural spacing of studs, while lighter lines could represent nailing / screwing distances. 

The precise gauging and cutting of materials on a job site is a particular problem for novices or self-builders. Robell’s method suggests specific / generic lines of productions for different building types and methods with different notations (metric and imperial) to imprint dimensional specifications on a material or product. 

US5673489A patent drawing

Prefabrication experiments - 245 - measuring devices – 06 – Dimensional Coordination and Elementhus

The pursuit of low-cost, quality housing has determined government programs and funded research activities with similar frameworks in wide-ranging settings. Often championed by large corporations or philanthropists much of this compiled research shaped and mapped out the construction industry’s progress. In the years following World War 2, in Sweden, large construction industry leaders such as Skanska financed the Home Building Research Corporation in an attempt to democratize cheaper but improved housing. This investigation considered modular coordination as the primordial standardization to bring about large quantities and streamlined production methods.  

Architects Lennart Bergvall and Erik Dahlberg were charged with the task of reporting back to the Research Corporation with specific gauges and metrics to help reform housing production. Their reports became the basis of additional investigation and controls published by the Modular Building Group in the 1960s. Further, out of this research partnership, the architects founded AB Elementhus, a factory built housing system based on the basic principles of modular and dimensional coordination: the assembly of a few continuously produced and interchangeable building elements and parts. 

Inspired by previous and similar studies, principally Bemis’ 100mm (4-inch) building matrix, the Elementhus components used a 200mm module (8-inch). Nominal 200mm x 200mm vertical and horizontal box beams were developed to structure walls, floors and roofs. The box beams, rectangular prisms cut to varied lengths, were laminated from hardwood veneer plywood and a sawdust/woodchip insulating core. Each box beams’ extrados and intrados flange was tongue and grooved and simply attached with dowels. The kit included bearing and spanning units and shorter lengths for below or above windows or around other openings. The patented assembly method and dimensions regulated the whole modular grid for arranging housing patterns. The factory produced nearly three houses per day and a total of 18 000 housing units during its operation. An emblem of streamlined manufacturing processes with a minimum number of interchangeable parts, the process used 100% of all its timber, for the panels, their insulation and fuel for heating and running machinery. Elementhus idealized modular coordination and symbolizes the type of dimensional and modular theories that were applied to the problem of accessible housing. 

Elementhus components