The USA has been central to the development of skyscrapers since technological innovations first made taller buildings possible, with Chicago’s 42-metre-tall Home Insurance Building widely recognised as the first skyscraper, opening in 1884.
The introduction of fireproof iron-framed structures with deep foundations, along with new inventions such as the elevator and electric lighting, made it both technically and commercially possible to take buildings to new heights.
The skyscraper continued to develop and became closely associated with the image of the United States, with increasingly tall buildings and ambitious architecture providing office, retail and residential space in high-density cities. This revolution in engineering and building design also presented new challenges for maintaining structures taller than anything seen before.
As an industry leader with decades of experience in facade access solutions, CoxGomyl has played a role in both the history and continuing development of tall buildings across North America and has been involved in some of the most significant projects in the United States.
200 Clarendon, Boston, formerly known as John Hancock Tower, was constructed in 1976 and remains one of the most recognisable buildings in New England.
Over the years, the building has presented a number of engineering challenges, including warping walls and the replacement of thousands of reflective glass panels. CoxGomyl was entrusted with overhauling the original 1970s window-washing systems and providing modern solutions for cleaning and maintaining the glass panels as well as practical access to the entire exterior.
CoxGomyl partnered with ECM to carry out state-of-the-art laser scanning of the tower and its surroundings. Together, ECM and CoxGomyl were able to provide a comprehensive analysis to support a complete retrofit, matching replacement components from the new system with the existing infrastructure.
In the city that was home to the first skyscraper, 151 North Franklin is one of the most technologically advanced buildings in Chicago. The 35-storey office tower features high ceilings and floor-to-ceiling glass designed to maximise daylight and provide views of the Chicago skyline.
This demanding project specified a single building access solution capable of reaching the entire facade, including areas underneath signage, while also providing a platform rating of 453.59 kg and capacity for three operators.
The BMU supplied by CoxGomyl provides 180-degree slewing capability in both directions and a maximum reach of 33.7 metres using five jib stages. The 9.14-metre cradle covers six horizontal window panels per drop, while a material hoist with a capacity of 680.38 kg provides additional functionality. Together, these features provide complete facade access from ground to roof level.
The Duke Energy Center features a distinctive sloping ‘chisel’ design at the upper levels and a crossbeam more than 20 metres above roof level, presenting significant challenges for facade access.
The BMU required a long reach while also being flexible and compact enough to manoeuvre into a very tight parking space. CoxGomyl designed a five-stage luffing jib specifically for the project, allowing access to all parts of the facade, including the extreme corners.
The cradle is fitted with a soft-rope system to allow lateral movement and provide access to the sloping roof areas, while an innovative lift platform lowers the BMU approximately six metres into a parking pit when not in use.
From overhauling and modernising ageing systems to designing bespoke solutions for challenging new skyscrapers, CoxGomyl brings extensive experience and technical expertise to facade access projects across the United States and around the world.
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