This new patient bed tower and vertical expansion, for which VAA is providing structural engineering services, utilizes metric dimensioning and measurement and a hybrid of British standards and American design codes. The project consists of an eight-story bed tower, six stories above grade and two levels of below grade parking. A portion of that below grade parking extends outside the tower’s footprint. A separate portion of the project consists of a vertical expansion extending two stories above the existing hospital facility.
Design of the tower has been completed and below grade construction has begun. The project’s proximity to the Persian Gulf causes the water to be close to the ground surface. Ground water level is within three meters of the surface and bottom of the below grade structure is approximately 12 meters below the ground surface.
Due to its depth below water level, the structure needed to be tight enough to prevent infiltration of water but also heavy enough to hold itself down against the massive buoyant forces of water. The main tower, being six stories above grade and two below, was heavy enough to resist those buoyant forces on its own. However, the two levels of below grade parking under the grass courtyard that extend outside of the building’s footprint were a different story.
Concrete tension piles were installed at approximately 5 meters on centers each way under a one meter thick continuous mat foundation slab to resist the uplift due to buoyancy. Close attention was paid to connections between the tension piles and mat slab to ensure their capacity to resist the tremendous uplift forces. In addition, careful detailing of waterproofing at pile/mat intersections was included in the structural drawings.
The ground level and first level below grade are designed as concrete flat slab construction with drop panels at the columns. The remaining floors of the hospital tower are a one-way concrete beam and slab system. The mechanical space on top of the building is a steel framed moment frame system. Laterally the building is supported against earthquake forces by concrete, cast-in-place, sheer walls at strategic locations that were negotiated architecturally.
Dubai is a city full of innovative construction design. The architect looked to us to help them deliver a visibly appealing modern design clad in glass and stone, suiting the owner’s desires, and meeting the needs of the facility. VAA was able to design all of the sustaining structures and capabilities into the building that are required for the running of a hospital. For instance, a linear accelerator is located in the facility requiring massive concrete construction to prevent radiation penetration, weight and vibrations. Large water tanks, domestic water and fire suppression tanks, very common in Dubai, are located in the basement and a large electrical facility is also located in the lower levels of the building adjacent to parking. All spaces above grade include hospital functions such as patient, medical and surgical rooms.
The U-shaped tower floor plan includes a clear height atrium of glass and metal. The atrium serves as the main entrance of the tower and incorporates long fin-like structural steel cantilevers projecting horizontally from the roof.
The VAA team works closely with the Ellerbe Becket architectural, interior design, mechanical and electrical design team in Minneapolis as well as with the architects and engineers of record in Dubai, UAE. Dubai continues to utilize building systems that differ from the United States. Our design needed to use materials that were appropriate for the building community there. One example is the use of masonry walls for the back-up to all the exterior wall systems. This adds to the overall mass of the building creating additional seismic design challenges.
The vertical expansion portion of the project has begun, but is temporarily on hold awaiting owner decisions.
