The Architectural Accomplishment of Ithra

The idea of architecture carries an intrinsic notion of creativity, whereas a builder generally follows a well-worn path. Engineering on the other hand is the stuff of nuts and bolts – sufficient structure.

Of course, this is hardly the reality of major building projects. Engineers are often the people who come up with the ideas of what is possible with the materials and techniques at hand. The bigger the project, the more it requires an integrated team.

The year that it opened, Time Magazine named the King Abdulaziz Center for World Culture (Ithra) to its 2018 list of the 100 greatest places to visit in the world. The Norwegian architecture firm Snøhetta certainly deserves a great deal of credit for the design of Ithra, a building which is not only iconic but structurally and architecturally unique in many ways. Yet Saudi Aramco also deserves credit: The company financed and stayed with the Ithra project – leaving their comfort zone well behind – for a dozen years from when it was just a dream about a major library until the cultural center opened its doors to the public.

Another key player was the British engineering firm Buro Happold, which provided a range of services to the project: structural engineering, sustainability, acoustics, building services engineering (MEP), facade engineering, lighting design and more.

The whole story, however, is far more complicated. Aramco management had a vision. They compiled a team and then held an international juried competition. The winner, Snøhetta, also had a vision. And then there were extraordinary challenges relating to climate, materials, process and programming.

One inflexible demand that Aramco made on the building team was that Ithra achieve LEED Gold certification for sustainability. And it did.

SUSTAINABILITY

Leadership in Energy and Environmental Design (LEED) is a globally-recognized sustainability certification that uses rating systems for every phase of making and using a building – the design, construction, operation, and maintenance.

Water use, for example, is very important to the LEED process. Being a desert structure, this is particularly important for Ithra. Xeriscaping, a low irrigation landscaping technique, is the most obvious example in Ithra’s sustainable design. Ithra’s grounds – and even some of its interior spaces – feature local flora in arid beds next to imported species from Australia and Arizona. Smart water controllers optimize irrigation levels based on the local landscape, weather and gray water collection to prevent over-watering or erosion-causing run-off. Efficient water use is even built into the plan for cleaning the building twice a year. Less obvious is how the xeriscaping dovetails with the structures of Ithra’s underground spaces.

In a spot caught between the desert and the sea where temperatures reach 52 degrees Celcius, solar heat gain is a primary environmental concern.

Ithra’s form is striking. Loosely, it is based on the idea of a group of five stones. There is functional metaphor in its layers: The ground level stands for the present, below is the past, and the upper elements represent the future. Yet, this incredibly forward-thinking and future-oriented building is 80% underground. Metaphorically, that may be ironic, but from a sustainability perspective, it is not at all.

The architects addressed the sense of being below grade by creating three “oases,” courtyard-like spaces open to the sky featuring light-sharing windows. This is also the logic of the Ithra Museum that spirals down three levels from the central “Plaza” to an atrium-like space at the center of the building with a fountain and a work of art, “The Source of Light,” Italian artist Giuseppe Penone’s 30 m tall stand of bronze trees that reference the “Prosperity Well” – Saudi Arabia’s first commercially-viable oil well. The site of Ithra was selected in honor of this original, nearby well.

Regional domestic architecture, like Roman villas, was often centered around a courtyard, in no small part to minimize solar heat gain. This logic is hinted at by the “oases,” but it was a primary goal of Ithra’s truly unique architectural signature – its steel-pipe skin.

The iconic Center is the leading feature of Dhahran’s skyline. The building and its facilities cover more than 80,000 square meters and include the four-floor Library, 18-floor Knowledge Tower, three-floor Idea Lab, Energy Exhibit, four-gallery Museum, 300-seat Cinema, 900-seat Theater, Archives, the multipurpose Great Hall and the nation’s first Children’s Museum. What people see, however, is a standing-stone towering over four other forms, all of which are wrapped in a skin of steel tubes.

MASHRABIYA

Snøhetta wanted to clad the exterior of Ithra in metal. This created challenges, beginning with solar gain – heat built up on the outer skin. As well, most metal would be vulnerable to sand abrasion over time.

The resulting solution combines two main elements: a weather-tight envelope with a feature shade veil wrapped around it. The shade veil is the steel tube skin for which Ithra, along with its iconic shape, is best known. The reflective stainless-steel tubes shield the facade from the scorching Saudi sun. Each steel pipe was individually bent and labeled by a specially designed machine to follow the organic curves of the building. Each tube is unique.

Ithra is wrapped in 93,403 steel tubes that totaling more than 360 km in combined length. The tubes are just over 75 mm in diameter and made of 2 mm-thick Duplex 2205, one of the hardest types of stainless steel.

Designing such a complex matrix – with each tube needing to be so precisely formed – had never been done before. The German contractor Seele GmbH created self-learning machines and software specifically for the task. The tubes, which were ultimately manufactured in the region, are exactingly spaced about 10 mm apart and attached to the weatherproof interior skin by titanium pins.

Ithra’s steel-pipe skin was the first of its kind in the history of architecture. The connection to the logic of local architecture, however, goes back centuries to a window structure designed to let light in and keep heat out – the mashrabiya.

A typical mashrabiya appears as a latticed wooden box projecting from a window on the second story or higher. These would allow for air to flow in from the cooler, shaded street and for warm air to flow out of the house through the larger grates at the top of the mashrabiya. Jars of water would be stored at the base of the cantilevered window box, further cooling the entering air. In addition to creating air flow in the house and blocking direct sun, these windows also offered privacy: Occupants could easily look out without being seen.

Using the flow of air to direct the heat away from the building is precisely the role of Ithra’s steel pipe skin, in addition to the far more apparent function of reflecting sunlight away.

The vernacular cultural history of the mashrabiya is overtly celebrated in Ithra’s design by the geometrical support screens that surround the covered walkway around the building.

THE MOST ANCIENT METHOD MEETS THE NEWEST

The soaring space of Ithra’s grand-gathering Plaza – the giant central hall of the building – features one of the most ancient building techniques: rammed earth.

Rammed earth is a combination of uncemented dirt, gravel and clay that is watered and then compressed into a structural form. Many of Saudi Arabia’s oldest structures were built this way, and there is new interest in the technique because of its extraordinary qualities of sustainability. Rammed earth insulates against heat from outside and controls humidity (despite the desert, the seaside Dhahran gets humid), thereby cutting air-conditioning energy use. It also dampens acoustics. A critical sustainability element of LEED certification is the use of local materials, and Ithra’s rammed earth project proudly used earth from the Kingdom.

While the Ithra team shunned the use of cement in the rammed earth component of the unusual material approach to the sustainable building, concrete was used for the curving walls of the entrances, twisted Plaza columns and artistic elements such as the mashrabiya walkway screens. In turn, Ithra also earned the American Concrete Institute’s highest award – “Excellence” – in concrete construction in 2019.

The Ithra team worked with the current almost-solo champion of rammed earth, Austrian architect Martin Rauch, to incorporate the technique into the design. Rauch then came to Dhahran to train Saudi contractor Fahad M. Al-Suwayeghin the formerly fading technique. The result in Ithra’s Plaza is a visual contrast between most ancient rammed earth walls and the uniquely new swooping system of steel tubes. One might be an architectural ancestor, but they are brothers in sustainability.

- Words by Daniel Kany