Plaza 66 Shanghai - China
At 288m and 66 storeys in height, Tower 1 of Plaza 66 represented a significant impact on the skyline of Puxi (west of the river Pu) Shanghai’s exclusive old quarter, several miles removed from the new city under construction in the former green fields of Pudong (east of the river).
The depth of the structure was also a significant departure from historic precedent, owing to extremely soft ground conditions. Millenia of Fluvial and alluvial sediment from the Yangtze River and the east China sea have deposited over 300 metres of sands and clays over the bedrock. This has created the land of Shanghai, which literally means “Up from the sea”. Prior to construction of Plaza 66, the deepest piles in the area were under the Portman hotel, extending to a sand layer located at a depth 40 metres. For Plaza 66, the bored piles are twice as deep, extending to 80 metres in depth. The bored piles were constructed under bentonite slurry using reverse circulation airlift for cleaning of the excavated pile shafts. Very large settlement estimates were incorporated into the construction methodology and are approximately 10 times greater than observed settlement to date.
The building structure is composed of slab and beam concrete floor construction, centrally located shear walls around vertical transportation and services risers, and three levels of outriggers from core to perimeter columns to stabilise the core in the slender dimension of the buiding, which presents a 12:1 height to width aspect at the south façade.
Chris Bakkala was lead structural engineer from concept through to completion on site including 3 years as resident engineer.