CW looks into the role of a high-rise committee and code in building tall buildings in India, along with case studies that lay emphasis on measures to ensure speedier construction.
Tall buildings are inevitable in major towns and cities in India where land cost is high. Today, in urban India, it is an encouraging market with the prospective potential being huge. Apart from Mumbai, where building tall has become a trend as well as necessity, Kolkata has also started witnessing the construction of tall buildings. Further, in recent times, Chennai, Bengaluru and Hyderabad have witnessed the growth of tall buildings.
Height and time
Considering the average height of a tall building as 70 m, the time required to construct one, would depend on the demand and pressure. According to Kamal N Hadker, Managing Director, Sterling Engineering Consultancy Services, ¨If the client wants the building ready, the skeleton, foundation and everything can be completed in two years; for finishing, maybe six months more without sophisticated technology.¨ And Vinod Prabhudas Chithore, Chief Engineer, Development Plan (Mumbai), and Member Secretary, High-Rise Committee, Mumbai, adds, ¨With the latest technology available and depending on the number of floors, construction time varies from three to five years. Assuming 70 m, a 21-22-storey building takes about two to three years to be completed.¨
Tall buildings have been built for over a decade in India but progress has been dilatory. ¨There has not been proportionate value addition in the way we build tall buildings,¨ says Alpa Sheth, Managing Director, VMS Group, adding that the entire tall building environment, starting from the process of building permits, construction technologies, tall building design strategies and quality assurance systems, needs greater sophistication and streamlining.
In Chithore´s view, traffic congestion and clearance from the civil aviation authority are two key challenges faced in the construction of tall buildings.
And Hadker points out that as we are relatively new in the field, we don´t have sufficient number of experienced contractors to go tall. ¨We lack experienced supervisors to control quality,¨ he rues. ¨Hence, buildings are often built with scant respect for quality and this will have a detrimental effect on the life of the building.¨
Code and committee
One needs a uniform code for the design of tall buildings to make it a level playing field. ¨At present,¨ says Sheth, ¨this is lacking.¨ Informing us that the Bureau of Indian Standards is preparing a Tall Buildings Code, as the coordinator, she confirms that the code is in a fairly advanced stage of development.
Highlighting the dire need for these codes, she adds, ¨The present set of Indian codes were not designed for tall buildings. Of course, such codes exist elsewhere in the world. China has a detailed prescriptive code. Los Angeles and San Francisco have a more prescriptive code. The ASCE and IBC codes are also quite detailed in how to design tall buildings. Disaster management has to be seen holistically and not separately as fire, earthquake, blasts, and so on. And we do not have enough application of mind for disasters in our codes. However, things are improving and the National Building Code is also working parallel on this front.¨
In the interim, the formation of a High-Rise Committee, like Mumbai has today, could have its own benefits. It provides some kind of restriction as it is supposed to assess drawings for prospective high-rises.
¨The fact that somebody is going to check my design makes me conscious,¨ says Hadker. ¨I want to ensure I don´t make mistakes and, therefore, I pay more attention.¨
So, what else does the role of the high-rise committee involve?
Chithore briefs that the committee observes proposals based on structural stabilities in design. Committee members include architects, engineers and geotechnical expert. Then, the proposal is further studied for shadow analysis and traffic. For instance, if a high-rise is being developed on a main road, a study is done to understand the traffic intensity to be imposed on that particular road. Based on that, an alternate entry and exit is suggested to ensure proper traffic management.
The success factor
A collective will to commit to good design with application of state-of-the-art seismic and wind design technologies, adaption of the best construction methodologies and a good legislative framework with excellent implementation procedures for fostering a culture of excellence can combine to make tall buildings a success in India.
Hadker believes that architects and engineers taking complete responsibility for their designs and the contractor ensuring good quality of work comprise the right way forward for tall buildings. For our part, CW presents details of three upcoming high-rise projects in India in terms of stakeholders involved and the technology, materials and systems used to ensure quality and speedy construction.
Single residential tower at 245 m; 60 levels with ground floor, 56 simplex apartments and one triple apartment, Kolkata.
The 42 will redefine luxury living in the city of joy, Kolkata. On completion, the tower will be the tallest structure in eastern India, with a single generously sized bungalow apartment on every floor. Sudarshana Gangulee, Senior General Manager, Mani Group, shares more on the project....
Overcoming challenges with technology
Tall buildings present unique challenges in terms of design and construction. Concrete features prominently in providing the structural material for most cores and framing options, thus ensuring stability of the structure. For The 42, we have been using concrete grade up to M70 and steel of grade Fe600 (normally Fe500 is used). The concrete is temperature-controlled. Post-tensioned slabs are used to reduce dead weight of the structure.
We have also used piles more than 50 m long. This is an unusual pile length for Kolkata.
We have used PERI shuttering and safety platforms that optimise construction time schedules by significantly reducing construction times and increasing safety. The formwork system used here is a dramatic improvement over conventional shuttering and considerably reduces shuttering time, thus increasing productivity. The platforms allow for safe and efficient work.
Our structural modelling is done in SAFE for foundation and in ETABS for superstructure. REVIT is used for 3D modelling and coordination of different services.
Pumping concrete This is done through special concrete pumps of very high configuration.
Completing the construction speedily within projected timelines is essential for the commercial success of any project - and even more so in the case of a tall building project. At The 42, we have drawn upon some of the best talent in the world for designing and constructing the project. The construction technology being used, procedural systems followed and periodic reviews made, are all geared towards achieving time-bound completion.
The technology partners have been selected on the basis of their vast experience in creating earthquake-resistant tall structures. There has been no compromise made in terms of safety measures engineered into The 42. This earthquake-resistant structure has been designed as per the requirements of Seismic Zone III. The building conforms to guidelines of the Council of Tall Building & Urban Habitat, Chicago, and has been pre-certified with LEED Gold rating as per Indian Green Building Council (IGBC) standard.
At The 42, we have done two independent wind tunnel studies by two internationally reputed firms, RWDI Consulting Engineers, Toronto, Canada, and Windtech Consultants, Australia. The structural concept has been prepared by Magnusson Klemencic Associates, US, while the working drawings have been done by JW Consultants, Mumbai. JW Consultants has designed structures for over 80 tall buildings already built in and around Mumbai. This has been subjected to peer review by IIT Bombay and Jadavpur University, Kolkata.
Service floors are available at regular intervals to meet structural and MEP requirements, which need not be considered in lower height buildings.
Location: 42B Chowringhee Road, Kolkata.
Completion: End of 2017.
Project team: Created by a consortium of four major Indian real estate developers, including Kolkata-based Mani Group, Diamond Group and Alcove Realty, and Bangalore-based Sattva Group.
Technology partner: Dubai-based Arabian Construction Company.
Architects: Architect Hafeez Contractor, Mumbai; Subir Basu, Kolkata.
Structure and geotechnics: Magnusson Klemencic Associates, Seattle, US; J&W Consultants, Pune; IIT Bombay; Jadavpur University, Calcutta; Geocon International.
Wind tunnel testing: RWDI Consulting Engineers, Toronto, Canada; Windtech Consultants, Australia; MEP & Fatade; MEP Consulting Engineers, Mumbai; BES Consultants, Mumbai and Singapore.
Interior design: PIA Interior, Bangkok, Thailand.
Landscape: Design Cell, Delhi.
Foundation: ITD Cementation, India.
Structure: ACC, Dubai.
High-rise residential building at 196 m, 60 floors, Gurgaon.
Raheja Revanta was conceptualised with the vision to make the tallest residential tower in Gurgaon with all the luxury and amenities in the premises itself. Nayan Raheja, Executive Director, Raheja Developers Ltd, shares more on this project.....
Constructing such a tall building is never an easy job. Safety of the workers, pumping of concrete, material shifting, etc, at such heights is always a challenging task and if not managed or monitored properly, can be catastrophic. If such tall buildings are built with typical conventional systems, we might end up wasting time, money and resources. Although advance construction techniques of present days for superfast construction are costly from the investment point of view, if considered for the long term, they are an economical and smart choice.
The following have been used or adopted to overcome challenges in the project:
Pumping high-grade concrete vertically up to 100 m is being done using the static concrete pump by Schwing Stetter SP2800. It can pump concrete to a height of up to 280 m. The concrete is accordingly designed to make the pumping feasible up to such great heights.
The construction systems used in Revanta are by PERI, a German company, one of the best and expensive in the world, known for superfast and world-class construction quality. The prefabricated shuttering scaffolding system and rail climbing system designed by PERI have decreased the slab cycle from 20-25 days to five to six days, thereby increasing speed of construction and achieving a seven-day cycle per floor.
An experienced and dedicated safety team is active at site. Also, safety meetings are regularly carried out at the site on a weekly basis.
Location: Sec 78, Gurgaon.
Estimated construction cost: Rs.720 crore.
Completion: January 2017.
Owner/developer: Raheja Developers Ltd.
Main contractor: UAE-based Arabtec Constructions Company.
Project manager: Pranay Rohella.
Architect and principal design consultant: In-house architecture department.
Structural engineer: US-based Thornton Tomasetti.
Fatade engineer: Priedemann.
Civil engineers: Jatin Behal and Ashish Sharma for execution and respective site drawings.
Elevators: Kone Elevators.
No. of elevators: 12 high-speed elevators with a speed up to 6 m per second.
Omkar 1973 WORLI
Super premium residential - uber luxury project at Tower 1 - 267 m, 76 floors; Tower - 267 m, 77 floors; Tower 3 - 267 m, 73 floors, Mumbai.
Omkar 1973 Worli stands among the tallest residential towers in Mumbai. In an unprecedented move, legends from across the globe have come together to lend their expertise to the creation of this project. Raman Sapru, President-EPC, Omkar Realtors & Developers Pvt Ltd, shares more on the project....
As this is a city centre project with limited space available at ground for logistics, meticulous planning and implementation are most important. Owing to limited space, the storage of building construction materials is limited. Deliveries of materials are properly planned and monitored. Also, there are challenges with regard to movement of equipment, men and materials, which has to be planned in detail. The means of movements are as per peak time requirements.
Concrete is pumped with the help of high-end, high-performance special pumps using specially manufactured pipelines that provide concreting in time without any major stoppage owing to obstruction in pipelines or pumps. Routing of pipelines is important to ensure smooth pumping without any pipe blockages.
Speedier completion of the project is crucial for the stakeholders owing to potential cost escalation, timely delivery and project closures. We achieve this with meticulous planning, suitable use of technology and monitoring all activities involved in the project. We are using the most suitable and latest formwork system and cranes or material handling equipment to ensure speedier delivery.
We plan all the activities with safety engineering involvement and do a safety analysis before starting the activities. We use safety gears for protection of personnel working at site. We use proper engineering solutions to ensure safety against fall or windshield screen for site workers to work at heights fearlessly. We ensure use of proper methodology for all the work to ensure proper safety.
Completion: Progressively till 2017.
Owner/developer: Omkar Realtors & Developers Pvt Ltd.
Main contractor: Larsen & Toubro.
Architect and principal design consultant: UK-based Foster + Partners.
Structural and MEP engineer: UK-based BuroHappold Consulting Engineers.
Fatade engineer: UAE-based Inhabit.
Vertical transportation: US-based Lerch Bates.
Landscape architect: UK-based LDA Design.
Lighting consultant: UK-based DHA Design
No. of elevators installed: 51 high-speed lifts with a speed of 6 m per second.