ABSTRACT
The design of slender high rise office buildings usually adopts large columns and thick core walls to resist
heavy gravity load and high lateral wind load. The design becomes more challenging if the building has a
high slenderness ratio and a small floor plate, restrictions on building height together with the developer’s
intention to maximize headroom. For the Grade A Landmark East office building, these challenges were
coupled with a limited structural zone, the requirement for a long span structure and the architect’s vision
of a building leaning asymmetrically. The design required the suitable application of the structural
engineering technology to find a solution that both resolved the architectural design intent whilst
addressing constructability.
The Landmark East Building is located in the heart of Kwun Tong industrial district and consists of two
200-m high leaning towers with inclined columns leaning in different directions to express the
architectural intent. Both towers have more than 40 storeys and 2 levels of basement. The structural design
of the twin towers of Landmark East adopted the use of high strength concrete (Grade 90 for the columns
and Grade 60 for the core walls) to minimize the column and core wall sizes and mobilised the inclined
columns with the coupling action of outriggers to enhance the core wall stiffness. Long span posttensioned
beams were used to support the floors. The structural design proved to be easily constructed
with the contractor achieving a construction cycle of only 4 days per floor.
This paper presents the salient features of the structural engineering design and demonstrates that
buildability need not be sacrificed in the pursuit of good architectural design.
Keywords: Architectural design, Buildability, Foundation, Substructure, Superstructure.
