Bella Sky Hotel - taking precast concrete to the limit

The Bella Sky Hotel consists of two towers each leaning away from each other at an angle of 15°. The basic principle is vertical loadbearing walls with precast concrete hollow-core floor slabs.
At the ends of the building, inclined walls are used to carry the vertical walls above where they are undercut. At these junctions the horizontal forces induced by turning the vertical forces are huge, and need to be transferred through the floors into the longitudinal walls. The complexity of the structure comes from the number of openings in these walls for doors and services in conjunction with the enormity of the horizontal loads from the lean of the building.
The use of precast elements meant that the forces had to be transferred through the joints in the elements. Severe reinforcement congestion - plus the fact that most of the geometry throughout the building is unique - led to an enormous design and engineering effort required to produce a solution.
The final result is a simple, elegant hotel structure that with one of the greatest leans of any building worldwide jumps into the record books.