The Riyadh Tower The Riyadh Tower is poised to be the third tallest building in Saudi Arabia behind Riyadh’s Kingdom Centre (311m) and the King Faisaliah Tower (267m). Atkins was approached by the Al Ajlan Allied Group (AAAG) in 2008 to provide full design services for the 63000m² Riyadh Tower complex. With 42 storeys of office space, a 45m skyline void, four levels of underground parking and a retail souk that extends the architectural language throughout the site. The basic concept was derived from existing urban fabric blending with local patterns, forms, cultural and urban elements. THE DESIGN Receiving the proverbial green light from AAAG, Atkins created a design that focused on simple lines, elegance and timelessness. To that end, The Riyadh Tower is the first building in KSA to feature a screen system facade which wraps around the tower and covers the drop-off zone and the souk. Its complex single-curved shape accommodates the intricate pattern of the façades that extend up and over the tower. The continuous freeform extruded geometry of the shape along with the wrapping of the façade from one side to the other produce an architectural gesture of distinctive form and a singular mass amidst the urban fabric. The obscured façade was strongly influenced by the concept of the mashrabiya, an element of traditional Arabian architecture that has been used on street-facing windows in the region for hundreds of years. The function of The Riyadh Tower’s mashrabiya-like façade is twofold: first, it is an effective symbol of the barrier between public and private space. This is a role mashrabiya have played in Arabian culture and architecture for generations and one that is revived in this contemporary application. The second function is the more practical provision of shade and protection from the hot summer sun. A slightly more superficial interpretation could also apply. Traditionally mashrabiya were said to be the ornaments of the rich as they cost a lot of time and money to produce. However, the mashrabiya is a purely functional device: Natural lighting is important to offices. The mashrabiya skin around the tower protects and shades it from the harsh northwest and southeast sunlight, allowing soft natural light to filter through to the offices. The street-level architecture is one of texture and pattern. The tower has integrated shading to maximise its considered orientation while the souk is an outdoor space with one-storey pavilions laid out in a traditional manner to channel the prevailing breezes between and over them. INTERIOR ARCHITECTURE Taking advantage of The Riyadh Tower’s location, its offices occupy more than 35 floors of the tower and are carefully oriented to maximise the surrounding views of the city. An open-plan concept of the typical tower floor plate was adopted for flexibility within the space and at the lower levels, the floor plates are formed by combining two ellipses. These floor plates gently taper into a rectangular plane as the tower ascends to its peak of 224 meters, forming an elegant and distinctive visual tribute to the locality. Sun path analysis was used extensively to understand how shadows would fall on the building, how they would affect the inhabitants and whether or not they would obscure or impact the surrounding structures. The intelligent skin of The Riyadh Tower can sense the internal needs of the skyscraper and can adjust levels of light, shade and air circulation accordingly. The skin of the façade of the tower has been designed in such a way as to define modularity at human scale. The screen system of the façade is identified by two key modules that get repeated along the façade transforming from mega-webs to micro-web pieces. GREEN CREDENTIALS With the greening of architecture around the world and the existence of the budding Saudi Green Building Council, sustainability is at the forefront of KSA’s burgeoning architecture industry. Even the earliest stages of design on The Riyadh Tower complied with worldwide initiatives to reduce energy consumption and carbon emissions, employ passive design strategies, improve engineering systems and create recovery strategies. Primary aim is to ensure emissions of carbon dioxide are minimized through reducing energy usage where possible and promoting energy efficiency throughout the project. Passive design strategies including analyses of building orientation, site location, shading, solar insolation and view were all conducted to ensure sustainability. Moreover, summer insolation analysis was used to optimize building orientation, determine window placements and develop external shading design. Decreasing solar radiation, reducing cooling loads and offsetting conventional cooling requirements where possible are all feasible energy strategies that can be credited to the design of the tower and initial studies. High performance glazing was also chosen to limit solar heat gain by blocking infrared and UV rays wherever possible. The successful integration of physical and social design throughout the development creates an architecture that is both environmental and socially sustainable. CHALLENGES The Riyadh Tower came with its share of challenges. One of the most notable challenges was designing and developing the skin of the tower. Its three-dimensional curves made up of horizontal as well as vertical convex lines required special attention. A second significant challenge was to maintain a floor plate efficiency of 80% over the entire floor area. As the tower rises, its floor plate gradually decreases in size. After several design studies and exercises, the tower core is reduced proportionally and accordingly for the smaller plates at the upper floors. Zoning the vertical transportation and utilizing high-rise and low-rise lifts had to also be taken into consideration. ACHIEVING TIMELESSNESS From its inception, AAAG wanted a landmark building. The words uttered time and time again were “luxury`, “modern` and “elegance` and Atkins sought to fulfil that brief with an aesthetic yet feasible solution. We visualized The Riyadh Tower as a modern landmark that led to developing a fundamental form with simple lines and shapes. The tower’s unique blend of architecture, artistry and culture manifest the character of a well-balanced landmark.