BRIGADE TECH GARDEN-B4 at Brookfield’s, Bengaluru – has 2 levels of RCC floor plate to suit the circumference of the Dome and envelope the whole space with a Dome shaped structural system which receives either concrete or glazing as an envelope. Sterling was involved as Structural Engineers for both RCC and Structural steel frame works.
After the Architectural concept was frozen, visualization of structural system, its varying profiles at different cross section, thinking about the material which can be used, arriving at a structural system which could be implemented, inspection of fabrication process, identifying the difficulties and wastages, after shifting the materials to site addressing the various difficulties during execution and finally obtaining the profile close to its intension.
Spray Concreting was first time used in building in Bengaluru where proportion of accelerator used in concrete and completing the concreting to the closest profile. Thereafter waterproofing and finishing.
Structural Aspects
This was in two parts.
1. The whole dome
2. The façade with curved surface with glass profile.
The entire structural profile including both the aspects i.e., glazing and concreting were analysed for various section and adequate sizing of members and its fabrication. The loads of the suspended partition weight also needed to be evaluated and executed.
Challenges
• Architecture and façade consultants gave the profiles at different section of the Dome. Creating computer model of all the profiles and analysing it in 3D
• Designing of all the frames of different sections including the change in curvature in width of the members to minimize the members protruding out of the surface adjusting the support systems to the RCC building.
• While executing lot of difficulties experienced in holding down.
Salient Features
3D model of various cross sections having different load condition on each frame because of concrete and glass and executing them at site.
It is the combination of section to obtain the profile which has got different loading conditions and adding to structure. Spray concreting over the entire surface of the Dome required to be done.
“The Clients requirement and the architectural designs, several alternatives were discussed and all of them were either to be imported or very expensive. I felt that this can be achieved in Indian conditions much more practical and cost effective, watertight alternative. The process of arriving at a solution was to define the geometry of the structure from 3D model. This was given to us as Data & we visualized the structure as series of sections at close intervals in order to achieve 3D profiles. A 3D computer model was generated in which every member is to be profiled differently including the inclination of Top flange. Further to reduce the cost, few internal columns were picked up to support the roof with tetrahedron members meeting different members in different inclination.
Fabrication also had lot of challenges in order to minimize the stages, computer software was used to cut the webs to profile and bend the flanges with strips. These were fabricated in the workshop under moderate controlled environment. In order to meet the variations in connecting the base structure, some alterations were needed since the profiles in continuously varying. MS sheets with stiffeners were used to moderately get the profile as desired.
The very important part of the work was using the spray concrete with injection of accelerator to stick to the surface against and along the gravity. The finishing works were carried out more accurately and subsequent waterproofing and final finish. Extremely happy for achieving this structure.”
Nagendra Kumar, Director, Sterling Engineering Consultants Pvt Ltd
Factfile:
Developer: Brigade Enterprise Ltd
Architect: Zachariah Consultants
Structural Consultant: Sterling Engineering Consultants Pvt Ltd
PMC: CBRE
Façade Design : Building Envelope Specialist (BES)
Steel Suppliers : TATA Steel
