Singapore Marina Bay Sands Constructed with High Technology Engineering
Marina Bay Sands is a 929,000-square meter (10 million-square foot), high-density and mixed-use integrated resort complex that brings together a 2,560-room hotel, a 120,000-square meter (1,292,000-square foot) convention center, a shopping mall, an Art & Science museum, two Sands Theatres, six restaurants, and a casino. It is located in Marina South, a peninsula of land reclaimed from the sea in the late 1970s across the bay from Singapore’s Central Business District. Conceived as not just a mere building project, but as a city microcosm rooted in Singapore’s culture, climate, and contemporary life, the project anchors Singapore’s waterfront, creating a gateway to Singapore, and providing a dynamic setting for vibrant public life.
With a program of nearly 2,600 hotel rooms, the most efficient massing would have resulted in a monolithic and wall-like building. Due to its prominent location within Marina Bay in Singapore, it was decided that three towers would be created instead of one. Each concrete tower hotel is designed at a height of 55 stories. Spanning across the top of the three towers is a 1.2-hectare (3-acre) SkyPark, a new type of public space, framing large “urban windows” between the towers. From the downtown area, framed views of the sea are created, and from the sea, a new city gateway is viewed.
Conceptually, each tower is composed of two slabs of east and west-facing rooms. The double-loaded towers spread at the base forming a giant atrium at the lower levels, and converge as they rise (see Figure 2). The tower slabs also give further character to the massing and relate to the site context: the glazed west side faces the city center while the east side is planted with lush bougainvilleas facing the botanical gardens and ocean beyond. In plan, as the parcel varies in width, the cross section is decreased from one tower to the next. The three void spaces are connected by one continuous and conditioned glazed atrium, filling the space between the towers with restaurants, retail spaces, and a public thoroughfare. Each tower slab form is also twisted slightly in relation to its pair, creating a dance-like relationship between the two parts and accentuating the slenderness of the buildings, resulting in the appearance of six towers, rather than three.
As the largest amount of heat gain occurs on the west façade, it was of paramount importance that an innovative solution be developed to maintain energy efficiency, without limiting the view from the hotel rooms to Singapore’s downtown.
The design solution proposed and imple- mented was a custom double-glazed unitized curtain wall. The energy efficient double- glazed units rest in a frame suspended from the edge of the slab. Perpendicular to the façade, glass fins were installed to provide shading. The outer skin follows the natural curved shape of the buildings, and the use of reflective glass creates a taught mirrored façade. One of the keys to achieving this aesthetic was a minimal spandrel panel at the
floor slabs (350 millimeters/13.8 inches), with a continuous double-glazed unit spanning the full 3 meters (10 feet) floor to floor. The glass fins are suspended out of the horizontal stack joint in order to allow them to radiate out in elevation. They are supported by a
3-sided aluminum frame, with the forward edge exposed, which catches the light of the sun, as well as reflections of the façade, to create a unique effect. The fins use a 30% reflective glass and are responsible for shading the façade for up to 20% of all solar gain (see Figure 4).
The east façade handles heat gain differently, utilizing deep planted terraces which follow the sloping radial geometry of the building’s profile. The planters help to create microclimate cooling, and the deep overhangs of the balconies naturally shade the hotel rooms from direct sun. Each planter, filled with bougainvilleas, will in time cover the majority of this eastern façade.
One of the primary design issues tackled by the architects and engineers was building movement. The unique design of three buildings connected by a SkyPark called for many engineering innovations.
The dynamic properties of a tall building structure are particularly hard to predict as many elements contribute to the building movement. The wind engineers carried out extensive wind testing on the towers and SkyPark to provide the design team with the data necessary to develop the design approach. In addition to determining the loads for each tower in isolation, it was necessary to predict the behavior and movement of each tower relative to the others.
This allowed for strategies to be developed for the steel-spanned SkyPark, as well as to determine appropriate measures to guarantee the safety and comfort of the building users. The site and surrounding buildings were modeled at a scale of 1:400 and tested in a wind simulator. Mean and gust wind speed ratios were measured at 28 locations on the SkyPark model. The measured wind speed ratios were then combined with a statistical model of the local wind climate to determine the predicted pedestrian comfort in and around the development.
The studies also showed that each tower could sway as much as 250 millimeters (9.8 inches) from center. To deal with the differential building sway, the engineers developed a series of aluminum and stainless steel plates, and multi-directional bearings, located at the bridge spans between towers, which act as sliding components and allow for the natural and individual movement of each tower.
The continuous 150-meter (492-foot) long infinity edge pool was also a challenge, and underwater movement joints were designed with interconnecting three distinct 50-meter (164-foot) stainless steel pool enclosures into a flexible singular whole. In order to test the design, a full scale mock-up of the design solution was built and tested under movement conditions (see Figure 8). In addition to building sway, the pool design also accommodates building settlement, and is built upon adjustable steel jacks, which ensure the infinity edge will maintain its horizontal level over time.
The principle challenge for the Marina Bay Sands project was the combination of complex design parameters matched with a very fast project schedule, from initial sketches to substantial completion within four years.
This meant arranging close and intensive relationships between the engineering, construction management and design teams on site, such that coordinated solutions could be quickly negotiated as they arose.
The success of the project lies in the fact that the inventiveness of the design (the concep- tion of the hotels and the SkyPark) was matched by an equally inventive and novel approach developed by the engineering and construction teams.