Prefabrication experiments - 343 - Platforms, DfMA, precast concrete components

 

Is the present platform or DfMA theory applied to building construction just another way to tweak the vocabulary associated with the factory production of edifices or is it the future of offsite construction?  Both, platform and DfMA, sometimes used together or interchangeably reference a type of systemic conceptualization of building production from repeatable processes and manufactured parts. How is this narrative different from kit of parts prefabrication, industrialized building systems or modular building components procured and specified by architects to construct an individualized building? The short answer may be: it is an era specific concept where platform business models and DfMA optimization driven by digital technologies are being presented as ways for streamlining the building process and generating economies of scale in construction. 

 

Precast concrete components for buildings have a relatively short (a century or so) but rich history of illustrating how different building typologies can be constructed with the same components; stairs, wall panels, floor girders, posts, trusses and beams all part of a manufacturer’s efficient procurement and production strategy are designed, fabricated, catalogued, and made ready to be specified for assembly. Precast concrete component producers have been, in a sense, proposing platforms since their early inception by pioneers like Ernest Ransome or Julius Kahn. Minimizing site work and optimizing the industrial process is at the core of this type of systemic construction process. Defined by modularity, typical spans, assembly details, architects can simply pick and specify elements according to company literature and standardized detailing to mitigate risks associated with onsite construction. This methodology essentially outlines how authors and proponents unpack DfMA for buildings. 

 

The major difference with industrialized building systems of the past is the symbiotic relationship that can be developed between all project stakeholders through digital modelling. Architects or engineers need not redraw or even question components as most precast component manufacturers are offering detailed 3d models of their elements for designers to populate their BIM models with production ready data. DfMA applied to architecture, while original in the way it proposes a much more collaborative way of optimizing design for production, it does not revolutionize architecture or construction it simply puts a new spin on a century-old idea. 

Structural precast concrete components

 

Prefabrication experiments - 342 - House Zero by Icon with Lake / Flato architects

 

Construction is a production sector often labelled as resistant to change. True innovations are rare and difficult to integrate as the industry remains highly fragmented and largely represented by small businesses that produce a portion or fragment of finalized buildings on site in the same way they have been for decades. Certainly, materials and methods are adopted to make site building simpler, but by and large construction evolves sluggishly. The current era seems to be an exception to this rule as technology, the need to construct a significant amount of housing globally and labor shortages are driving the implementation of digital design, connected management tools and manufacturing methodologies like volumetric modular to update building construction. Digital technologies are disrupting the construction ecosystem from fabrication to production with completely new ways of making components and erecting buildings. 

 

Additive manufacturing or large-scale 3D printing is one of the approaches being described by many as the solution to construction's lagging productivity and the housing crisis. Lake / Flato architects have partnered with Icon (large scale 3D printer developer) to construct a mid-century modern inspired prototype to highlight these new potentials. The house is based on the pretty straightforward process of applying layer upon layer of concrete to shape thick bearing walls. Walls can be made to include windows, doors or any other architectural component. A timber conventional roof structure spans the bearing elements and curtain walls to complete the envelope. At the heart of this design is its production device; the Vulcan 3d printer, a large gantry crane secured to a mobile frame. A nozzle at the end of a pump is attached to the crane and a cement based concrete mixture is deposited in any direction and height limited only by the printer’s maximum travelling dimensions. The printer can be used to produce walls that are completed on site with more conventional construction methods. The Icon – Lake/Flato prototypes are inspired by midcentury modern aesthetic and aim to be affordable, however the streamlined use of large-scale 3d printing remains marginal and still a few years away from being an efficient response to the affordable dwelling needs. 

Houses Zero image and Icon 3D printer nozzle

Prefabrication experiments - 341 - Gamma building system

 

In the latter half of the twentieth century, reaction to large scale building programs and mass-produced heavy prefab systems induced critical discourse and counterproposals to the «closed» box and panel concrete building systems infamously deployed all over Europe. Repetition and raw construction formed the basis of negative press in architecture and criticism from the public. During the 1970s in France and really all over the industrialized world that had been marked by large scale building projects, public policy encouraged architects and industrialists to explore new lightweight construction «open» systems to achieve flexibility and adaptability that were deficient in heavy systems. 

 

A now famous design competition in the early 1970s, «PAN» Programme d'Architecture Nouvelle (program for new architecture) in France offered young practices a chance to come up with alternative dwelling designs that would respond to the need for flexibility. Parisot architects' Gamma building system was designed in this context and to argue for a type of structure and infill adaptability.  The steel skeletal structure spanning 7 to 10 meters defines an «open» filigree framework that embraced the topology of its supporting mountainside in Nancy, France. A lightweight megastructure, the scaffolding-like exposed steel (painted black) frame became characteristic of the building kit. Stairs, gangways, and suspended passageways were hung from the structure with dwellings units inserted into the metallic latticework.  Floors were composed of steel decking covered with composite timber.  

 

The contrasting light-coloured dwelling volumes were fabricated using a stressed skin steel lacquered composite panel with a polyurethane core. Both light and flexible the panels could be assembled to shape any size dwelling. The Gamma proposal used a pattern of reproducible stacked box units interconnected by the exterior structure’s network.  The Project's life span was mired by acoustic, insulation, waterproofing problems and was abandoned relatively quickly after its construction. It was a built prototype that should have been used to evaluate and perfect all its elements before its testing it in the field. The separation of structure and dwelling units remains an interesting concept for offsite efficiency as apartments can be produced independently of the site-built structure without worrying onsite construction challenges.

Gamma building system

 

Prefabrication experiments - 340 - Ycube modular units

Stacking modular units has long been presumed to revolutionize building construction. Producing identical dimensionally coordinated boxes professes to save time and money. Units are manufactured while work proceeds on site abbreviating the linear process associated with conventional construction. Bringing complex coordination into the factory is another one of the major selling points of this type of building system. Even with its advantages, why has it been so difficult for modular to gain traction as a generalized building method? Perhaps the reason lies in the fact that in order to optimize costs design standards are repeated from one unit to another and further from one building to another as the only type of logical and successful application of modular construction is deploying identical units. This required repetition has challenged architects' quest for singularity. 

 

This quest for originality seems to be changing as undifferentiated objects and commodities increasingly inundate our lives. Age-old connotations associated with prefab are being transformed by globalization. Architects are rediscovering the systemic nature of offsite construction they had abandoned through the latter half of the twentieth century. The affordable housing crisis along with architecture and construction’s digitalization is driving a new era of experiments to creatively unite architecture and standardization. 

 

Y-cube designed by Rogers Stirk Harbour and Partners for a YMCA in South West London is a prime example of modular and manufacturing values applied to architecture. The building is made up of repeating 4 x 7m units: a simple 1-bedroom apartment to reintegrate vulnerable populations. The container-like units are stacked and aligned without modifying their design. Exterior appendages for circulation, exits, and canopies are added to the simple boxes to introduce some customized and customizable components.  Related with the platform approach to building being promoted in the UK by Bryden wood, all required elements could be itemized, classified and purchased in bulk and distributed among several nuanced projects. Volumetric subassemblies and other modular elements, timber columns, slabs for gangways, can be developed as part of modular kits using harmonized supply chains to increase efficiencies and increase affordability.  

Y-cube system by Rogers Stirk Harbour and Partners