Prefabrication experiments - 202 - master industrialists - 03 - Henry Grey's rolled beam

Nearly all buildings produced in North America today combine some form of industrialized timber, concrete or steel construction method. The evolution from earthen, masonry or notched timber to skeletal systems to balloon or skeletal steel frames altered building culture and its logistics. In a relatively short time frame these two iconic building systems reinvented urbanit, sprawling horizontally (the balloon frame) and vertically (the skeletal steel fame), which globalized these efficient and flexible construction methods. Contributing to this development, the I-Beam is arguably the single most iconic building component that sustained the development of frame structures and still symbolises tall steel building construction. The I-Beam has been used in construction since the 1850s, its shape closely mimics the letter «I» with top and bottom extensions joined together by a central web portion. All through modernity architects used lightweight profiled metal sections to represent a new architectural language. 

The H-beam or the wide-flange beam also known as the Grey beam after its inventor industrialist Henry Grey, is an optimized structural shape. Loosely mimicking a rotated «H» its composing matter is extended from the beam’s centre of gravity increasing its inertia. Top and bottom plates or flanges resist compressive and tensile forces while the beam’s vertical web optimizes vertical reaction and shear resistance. Grey’s rolled structural shape was stronger than the previous built-up I-beams. 

Grey’s innovation is not the structural shape as beams of this nature were be riveted from plates to achieve similar results. Grey invented the continuous rolled beam shaping it directly from hot rolled steel ingots which made it cheaper, faster and stronger as it was a continuous shape; Further, simply adjusting the rollers could adjust height, steel thickness and flange dimensions. A large diversity of profiles could be mass-produced, cut and delivered and a greater rate. Controlling a simple industrial process, Grey developed the beams in 1902 while working for the Ironton structural Steel company of Duluth Minnesota.  Bethlehem steel gained the rights to the Grey beam’s production in 1908. The mass-produced profile established skeletal construction as an efficient scheme for building, is still produced in steel mills and remains an icon of  industrialized building culture.

technical drawing from Grey's patent application from 1904

Prefabrication experiments - 201 - master industrialists - 02 - François Hennebique (1842-1921), master influencer

Reinforced concrete is a truly modern material. Although already employed by Roman builders who employed pozzolans as the binder in a type of liquid stone, it was throughout the 19^thand early 20^thcenturies that the material was rediscovered and industrialized. The invention of Portland cement by Joseph Aspin (1824 patent) and later the steel mesh reinforced flower pots patented by Joseph Monier (1867) drove a plethora of explorations from Thomas Edison’s continuous cast housing system to Enest Ransome’s reinforced precast concrete block system. Reinforced concrete transformed building, as its properties seemed super natural: the compressive strength of stone linked with the tensile resistance of steel contained in a fireproof monolithic structure. 

Of all reinforced concrete’s protagonists François Hennebique’s contribution was arguably the most militant as he harnessed the power of architectural media and his own publication «le Béton Armé (1898)» to promote, inform and disseminate the potentials of Ferro-cement. This master industrialist was able to seize interest and reinvent construction on a simple idea and its description: Incase a steel or iron beam in concrete and it gains protection against fire. Replace the beam’s bottom and upper flanges with an alignment of smaller steel bars and then the beam’s web with regularly placed stirrups/loops to hold the bars in place and you have an ideal structural system which combines the advantages of concrete and steel in one thin  «indestructible and fire-proof» floor system. This same principal could be applied to girders and columns and to any building type. 

Hennebique exemplified the idea of the new master builder uniting manufacturing potentials with propaganda to deliver new products to market. Hennebique’s magazine, leaflets and brochures were used as influencing tools, more than an engineer or entrepreneur, Hennebique was a master influencer using his message to garner interest and projects. Winner of the Grand Prize at the 1900 Universal exhibition in Paris he advocated for the use of «fire proof» concrete in every building and proposed a new model for commercial partnerships between his office, le bureau d’études, with his version of the system’s franchisees, and engineers and architects. His model of industrial collaboration cultivated his reinforced concrete empire from 6 projects in 1892 to 1235 projects in 1899. 

Illustration from Hennebique System catalogue