Michael Bonewitz

15,600 Glass Blocks for a Spanish Memorial

”Nearly two years ago, SCHOTT was selected to be the manufacturer of glass components for use in building the glass memorial in Madrid,” remembers Lluis Trias. The product manager for architectural glass at SCHOTT Iberica in Barcelona was contacted by Dragados, the leading construction company in Spain and one of the most important builders in Europe. Dragados was hired by the city of Madrid to develop a unique construction concept for a monument made entirely of glass. According to the architects from Estudio FAM in Madrid, who were responsible for designing the monument, SCHOTT succeeded in becoming their supplier of glass elements thanks to its combination of design, material and reliability of delivery. The consulting engineers from Schlaich Bergermann and Partner, based in Stuttgart, Germany, executed the support structure planning.

To ensure timely execution of the project, a melting tank for manufacturing the 15,600 glass blocks was reserved early on at the SCHOTT site in Grünenplan. A unique challenge resulted from the requirements that came out of Spain. The blocks made of borosilicate glass had to be manufactured in round shapes, convex on the one side, concave on the other. This shape made it possible to bond them together in circular rows of blocks and, thus, create the cylindrical shape of the monument. One block alone weights 8.4 kilograms, measures 200 by 300 millimeters and is 70 millimeters thick. ”While manufacturing these, we had to pay very close attention to narrow tolerances,” explains Michael Quidde in Grünenplan, who managed the project on the sales end. The proven high temperature stability of borosilicate glass was also important. After all, according to the specifications, the material had to be capable of standing up to the extreme changes in climate Madrid often faces.

Similar requirements applied to the flat roof construction made of glass, as well. It, too, is made of borosilicate glass manufactured by SCHOTT at the German manufacturing site in Jena. The 10 and 12 millimeter thick glasses were manufactured using the float process and offer extremely high transmittance. To increase the mechanical strength, the glass was thermally tempered. This version is usually put to use as fire protective glass under the brand name Pyran® S. ”Even by our own terms, the dimensions and various sizes of the disks were quite uncommon. To add to this, we had to adhere to an extremely tight schedule,” says Lutz Nöthlich, who works in sales in Jena. The basic glass was manufactured in Jena and then processed with the help of the Austrian company Glas Gasperlmair in Wagrain. Here, three individual disks were bonded together to form a 30 millimeter thick glass laminate using a laminating process. Twelve of these laminated glass units form the roof of the monument.