The façade materials, taken from two different strata of Jurassic beige in the Altmühltal valley, were supplied by JMS, a company based in Eichstätt, Bavaria. It was here that the client and architect team, stone consultant and Canadian-based curtain wall engineer Antamex International Inc. were treated to a emonstration of fischer‘s sophisticated undercut technology. In the words of Hans Neumeyer, who as one of JMS’ partners was involved in technical counselling, „The FZP undercut anchor offers a technically efficient and aesthetically convincing solution – which is why we proposed it for this scheme.“
The project decision-makers likewise came to recognize the FZP‘s many merits, which include straightforward handling and secure installation in undercut drill holes using the automatic fischer SGB setting tool and the process and quality supervision concept developed together with Neumeyer &Brigl.
JMS proceeded to dispatch a total of around 13,000 m² of cut-to-size natural stone units – equivalent to 1,400 tonnes, filling 60 containers – with the necessary
undercut drill holes to Toronto-based Antamex International, which duly commissioned fischer to supply some 120,000 (13 x 21 M8W/22 A4) Zykon FZP anchors.
The load-carrying capacity of the fischer undercut system, which is three to five times that of conventional through-fixings, allowed the project engineers to reduce
the original stone panel thickness of 5 cm to 4 cm. The lighter façade lowered the structural loads, thereby cutting construction costs. The anchors used for the 101 Warren Street project, custom-developed for sandstone and limestone walling, have been granted a national technical approval by the German Institute for Construction Technology (DIBt) in Berlin. They are 13 mm in diameter and 21 mm in length. The embedment depth in the natural stone is between
16 and 20 mm. This method, known as stand-off installation, automatically compensates the tolerances in the thickness of the stones and the visible side of the natural stone façade remains totally smooth and level.
Antamex International specially equipped its factory with a new assembly line for the prefabrication of the façade elements. The fischer employees visiting the company‘s Canadian base were impressed by the high standards ofquality and professionalism. The around 25,000 stone panels were fitted together into 4,000 façade elements,with FZP undercut anchors set in the stone panels and bolted to an aluminium frame reinforced with steel girders. About 200 different natural stone or natural stone and glass façade elements were made using this method.
Façade builders must be able to combine different materials such as natural stone, glass, aluminium, concrete and steel, which will work only with an advanced
fixing method such as undercut technology. The Black Forest-based fixing specialists currently apply this highly developed technique in about 700,000 m² of façades every year worldwide.
The prefabricated units were shipped from Toronto to the New York construction site. Here, they were craned to their respective locations in the building, slotted into position, adjusted and secured in preformed holes in the reinforcedconcrete structural frame.
The great benefit of this erection method lies above all in the process-optimised production of the elements with their exceptionally high prefabrication level, the carefully co-ordinated, just-in-time panel delivery, the tightly scheduled, fast-track assembly process and the low on-site space requirement. The efficient prefabrication of curtain wall units in a factory environment guarantees a higher quality than can be achieved by assembling individual
components on site. What is more, this building method causes much less noise disturbance and dust emission than conventional façade construction.