COVER STORY
Sky Habitat resolves design challenges The project won a DESIGN AND ENGINEERING SAFETY EXCELLENCE AWARD, in the RESIDENTIAL CATEGORY, at BCA AWARDS 2016. INTRODUCTION Located over a site area of 11,997.10 m2, within walking distance to Bishan MRT Station and Junction 8 mall, Sky Habitat comprises two 38-storey blocks that accommodate 509 residential units. The development also features sky bridges at Levels 14, 26 and 38; an Environmental Deck (Edeck) on the 1st storey; and two basements of carparks. The design of the building was governed by a height constraint of 140 m AMSL (Above Mean Sea Level). All structures and fixtures above the roof top including TV antenna, obstruction lights, water tanks, lift motor rooms, maintenance equipment, lightning conductors, construction equipment as well as temporary structures like tower crane, were subjected to the same height limit. SAFETY IN STRUCTURAL DESIGN PROCESS AND SOLUTIONS Splayed shear walls Structurally, one of the challenges in this project was to analyse the stability of three major pairs of splayed walls of Block 7 (North Tower), which slope from Basement 2 to Level 14, as well as the design and structural detailing process. This is not a design that is commonly seen in any normal single block building. Therefore, suitable and valid assumptions and theories were considered carefully prior to the specific analysis and design process. The featured terracing units at the North Tower are laterally profiled and shaped vertically up along the splayed shear walls which give the overall rigidity of the structures. The shear walls are rigidly tied and connected at the Basement 2 floor diaphragm and Level 14, and are designed taking into account the tensile and compressive
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Sky Habitat features a three-dimensional matrix of homes with private terraces and common gardens, bringing about skyrise greenery and stunning views of the skyline. Image by CapitaLand Limited.
forces, so that the load paths can be closely looped. The three major pairs of splayed shear walls, aligned upwards to Level 14, support the structural steel trusses that transfer the loads from the upper stack of terrace units down to the shear walls. After viewing the valid analysis theory, the effective wall dimensions and critical load paths were determined, in order to provide a clear and clean load path for the load to transfer down to the foundation, safely. Therefore, several discussions were held with all the relevant parties to ensure there were no structural openings or any items that would obstruct the transfer load paths.
THE SINGAPORE ENGINEER October 2016
Structurally, one of the challenges in this project was to analyse the stability of three major pair of splayed walls of Block 7 (North Tower), which slope from Basement 2 to Level 14.