Gotz, the provider of technical solutions to building facades, has described its work at Prince Al Waleed's 300-metre tall, 30-storey tower, Kingdom Centre, Riyadh, as "one of the most demanding projects ever" from the standpoints of curtain walling and cladding techniques.

"It is true that the finished tower will be an object of admiration for several generations to come, as a symbol of human ingenuity, creativity and perseverance, but for Gotz now, and into the very far future, this tower will forever be a symbol of success and accomplishment," a Gotz spokesman said.

Awarded the contract in 1999, Gotz custom-designed various elements from profiles to brackets to gaskets.

"Being of a very complex and intricate nature, the project had to go through a long series of design and engineering tasks in order for Gotz to cover all the specifics of the various details," the spokesman recalled.

The project's facade surfaces had several types of glazing and metal cladding including four-sided thermally and non-thermally insulated structurally glazed units, open-jointed structurally glazed spandrel units and similar units with light boxes. The work also included two-sided structurally glazed units, frameless suspended-glass assemblies, canopies' skylights incorporating fritted laminated sunshade glazing, necklace and sky-bridge solid-aluminium cladding, special metal screening and podium canopies and columns composite aluminium cladding.

Other areas covered were water- and sand-resistant aluminium louvers at various technical levels, the observation deck glazing system at the sky bridge, conventional curtain walls at podiums' ground levels, a large-area automatic-smoke-discharge system in the shopping area and special large-span facade structures at tower and podium entrances.

"The majority of the curtain wall units installed in specific areas in the podiums, and throughout the whole envelope of the tower are mainly unitised structurally glazed elements, designed by Gotz," the spokesman explained, adding that the exterior elevation, having a 17mm joint between each pane of glass both horizontally and vertically, gave a "totally flush exterior appearance".

The units were manufactured entirely on the factory premises, delivered to site on flatbed trailers and installed using a Gotz-designed lifting system that operated at various levels of monorails. Cast steel brackets that allow concrete deviations of up to 40mm in all three axes (X, Y, and Z) received the units and secured them to the building. Commenting on the concerns Gotz addressed, the spokesman said: "Units spanning up to 7.3m in height were carefully designed and tested to meet the requirements of the most demanding specifications including typhoon wind pressures up to 2.6 KN/m2 in both compression and suction, and thermal cycling at extreme temperatures. The sand- and water-resistant aluminium louvered panels are homogeneously integrated along the two V- shaped ends of the tower at each of the four technical floors.

"The high-performance insulated glass, in addition to the spandrel single-glass panels are bonded with structural silicone adhesive to a carrier sub-frame under strictly controlled factory conditions, future replacement without the need to dismantle the primary framing members or carrying out structural silicone glazing operations on site is a major design feature."

The non-thermally broken system covering the upper sculpture area as well as the higher podium areas was "smartly engineered" to express the continuity and uniformity of two completely separated systems, according to the company. The sculpture units incorporated computer-operated light boxes, which were placed at regular intervals similar to those of the residential floors for the purpose of providing the sculpture with the illusion of being occupied at night.

Gotz also had to respond to an engineering challenge it said had "never been accomplished throughout construction history". This referred to the sculpture's cutout which created a large 79m high void whose outline was traced by an undulating 3D surface, the movement of which was further accentuated by 2,600 individual pairs of aluminium panels. The panels individually followed the surface as it moved to meet the observation deck bordering the void.

"Our highly skilled engineering team spent thousands of computer-aided design hours to develop real 3D models that were used to develop the production and installation documents. Aided by the most advanced laser-surveying equipment, our highly trained technicians were able to accurately transfer the computer-generated model into reality. Each bracket and panel was individually engineered to meet the required geometry," said the Gotz spokesman.

The observation desk's glazing screens' laminated glass reduces internal light reflection to two per cent, which allows maximum external visibility at all times and cuts solar heat gain by 70 per cent, while the stainless steel framing members are strong enough to withstand impact even if the glass is broken.

The glazing in the podiums is identical to that in the tower. The East Podium, housing a luxurious mall, has at the entrance two cantilevered canopies stretching out to reach Olaya road, each of the canopies being clad with specially formed aluminium panels. Other features of the East Podium are suspended glass assemblies (at the entrance) reaching up to 7 m in height and incorporating large panels weighing up to 460kg each, a long ribbon of conventional curtain wall (sealing the ground level) incorporating various doors, 9.2m high free-standing two-sided structurally glazed curtain walls incorporating electronically controlled smoke-discharge units and a wing-shaped high-roof canopy with supporting columns clad with aluminium composite panels.

The West Podium's main entrance has an aluminum composite panel-clad canopy that extends towards King Fahd Road and includes fritted skylight panels. A two-sided structurally glazed freestanding facade is supported by massive steel-bowstring structural trusses. An aluminum composite panel-clad canopy emerges from the upper podium area and is similar to that of the East Podium. The ground level is in turn sealed with a long strip of conventional curtain wall dotted with doors.

The Gotz Middle East facility at Riyadh's second industrial city has an area of more than 9,000 sq m including the production area and large storage and warehousing areas. The facilities include two machining centres and custom-built bending and cutting machines plus new design offices for engineering and CAD/CAM.

Many of the staff were previously employed by Armetal and Gotz GmbH. Gotz Middle East was formed by Armetal Metal Industries and Gotz Gmbh, a union that combined Armetal's customised stainless steel architectural systems with Gotz's expertise in aluminium high-rise curtain wall and customised facades.

Gotz Middle East has been a lead supplier to many important projects including Al Faisaliah Center.