Living the High Life
BY Jayashree Kini Mendes
The complexities of constructing high-rises are never-ending. While real estate developers are well-versed with building tall structures, there are several aspects that need careful consideration. Right from soil test to structural analysis to wind load, not to forget checking every material that goes into making the tall storey stand for decades to come are just some of the considerations. Over the last few years, developers are also required to adopt materials that help in conserving energy and water, generate less heat and waste and minimise maintenance costs.
Speaking about the company’s intent to offer best-in-class housing with a great sense of environmental responsibility and superior value for money for its customers, Rakesh Reddy, director, Aparna Constructions & Estates, says, “Everything that goes into our buildings has to contain these four attributes viz. efficiency, consistency, durability and quality. From that perspective, while we opt for top-quality building products as per industry standards, we do make sure that those products are not only a design treat to the eyes but also exceed our safety standards, are eco-efficient, and durable enough to sustain their operational lifespan.”
Aparna Constructions ensures that most of its building materials, such as RMC, windows, tiles etc., come from its own downstream companies so that it can maintain exacting standards. Its in-house R&D plays a big role in offering an assurance of the quality of products.
Every building is a complex structure of construction elements. The unique and appealing design of every property is derived after a meticulous mechanism. Explaining about some of the parameters that Akshaya considers when shopping for materials, T Chitty Babu, chairman & CEO, Akshaya, says, “The technology, designs and innovations are brought together from multiple renowned suppliers and we seek options so that we can offer an extraordinary product to customers. Each component that adds on to the making of a property at Akshaya meets the necessary guidelines for buildings. Moreover, they go through a battery of quality checks from structural design, consultants, architects, to material procurement.”
In terms of products, what adds that finish is the tiles. Ashish Mehta, president, sales & marketing, Orient Bell, says, “Tiles have increasingly gained popularity. Super gloss tiles are the most advanced technology and have perfect blend of strength and appeal. Advantages are low porosity, water resistant, acid and alkali resistance, frost resistance, high breaking strength and overall mirror like finish with bright colour appearance.”
Similarly, Construction Week attempts to deconstruct the numerous strands that make up the fabric of tall structures and gauge the challenges and solutions from companies themselves.
MIND MEETS MATTER
From the design point of view, it is the façade of the building that bears the brunt of acclaim and criticism. The biggest challenge is the wind pressure and the logistics. Kapil Chikodi, head, business development, Glass Wall Systems, says, “We have executed several projects that throw up design and execution challenges. Designing the system is most critical as we have to understand from the point of execution or installation at site. We have to make a feasible system to suit the condition at site without changing the architect’s intent.”
Glass Wall Systems has a core design team that takes care of challenges in façade for high-rises. “Another complexity is the construction methodology being carried out, as we see most of the construction has variations in terms of line and level. Sometimes the design intent is changed during construction to suit the site location. We have to execute the façade as desired by the architect because that’s the ultimate look for the building,” he adds. The company executed the façade project of JW Marriott Hotel Kolkata, which has a dia-grid for the three floor height lobby area and lots of curvature kind of flow. They used modern software and their design skill to execute the same. The team also believes in offering options of materials like clay tiles or HPL or GFRC or metal screen instead of typical ACP cladding material.
The challenge is to value-engineer the cost vis-à-vis the performance vis-a-vis the design intent of the architect without diluting the specifications of the façade consultant. Navin Keswani, MD, Aluplex India, says, “We adopt a technological value-based design principle by ensuring that the panel sizes are uniform. The big challenge here is to design the unitised system vis-à-vis the wind pressure vis-a-vis the deflection criteria for the system.”
High-rises demand complete performance of the architectural façade systems wherein façades are to be designed, engineered, manufactured and installed to high specifications which include low air permeability, high water-tightness, ability to withstand wind load, and an ability to cater to high deflections caused by seismic racking during earthquakes.
Keswani adds that his company redevelops the design sphere working in cross collaboration from the preliminary design stage to provide eco-friendly, energy saving solutions by incorporating new concepts where the façade is not just a passive filter between the external and internal environment but acts as an active component linked to the building physics.
Going forward, Aluplex hopes to design and engineer façades with BIPV (building integrated photovoltaics) wherein the façade panels are integrated with photovoltaic so as to not only reduce the energy consumption but also create energy for the building.
Considering the emphasis on high-rises, it is pertinent that buildings are constructed with strong emphasis on safety, and do not compromise on quality and sustainability. Babu of Akshaya says that developers must have a clear vision of the whole project and assess the building processes right from the choice of location, design elements, energy modeling to the sourcing of raw materials and disposal with adequate planning. It is necessary to take into account embodied energy, global warming potential, resource use, air and pollution, and waste generation.
Even during construction of high-rises, the contractor has to tackle with daily challenges. VG Sakthikumar, MD, Schwing Stetter Sales and Services, and chairman of mechanisation committee, Builders Association of India, says, “High-rises are seeing a rapid pace of growth. Day by day, the deshuttering time of formwork is seeing a reduction. Concrete has to be placed within the time frame as there are upcoming new technologies in shuttering methods like formwork. Maintaining concrete rheology till pouring point is the major difficulty during pumping of concrete at a high-rise construction. A set up is made for handling, holding, cleaning and maintenance of the concrete conveying high pressure pipeline.”
Schwing Stetter has high rate concrete placing equipment such as separate placing boom of SPB 25, 32 and 35 as well as truck mounted concrete boom pump in the range of 17m boom length up to 43m boom length, which gives optimum concrete placing output. It can also include a separate placing boom as part of the shuttering system itself to further reduce the setup time. Going forward, the company wants to bring in innovations in products to help them build taller buildings. These would be customised solutions for concrete conveying pipeline and clamping arrangement to improve pumping efficiency, compact placing booms to make the system feasible and improve output, easy switchover of high and low pressure systems in concrete pump hydraulics to save time and convenience in operation, and concrete pressure measurement system (sensors) to be incorporated so that concrete consistency can be monitored.
Typically, a high rise building is defined as a building with an occupied floor located more than 75 feet/24 metres above the lowest level of fire department vehicle access. It is also the reason why it is not only challenging to construct but also challenging in term of engineering design, such as pumping cold and hot water, and for mechanical uses, such as cooling towers and supplying HVAC equipment. Gangaprasad Rao, VP, sales (South), Grundfos India, says, “Plumbing in high-rises usually consists of vertical piping systems for water distribution and drainage/venting. Challenges are faced in pressure distribution of these vertical pipe networks in terms of cost, ease of operation, energy use and maintenance aspects. Another complexity is to limit the water pressure to the safe limit as required by the code/design of the building by employing pressure reducing valve stations at appropriate locations on the floor level. Though everyone agrees that use of pressure reducing valve (PRV) is sheer waste of energy, its use can only be minimised but cannot be eliminated altrogether.”
Pumps in high-rises are mainly used for water supply for domestic use and flushing, fire protection systems and HVAC in case of centralised air-conditioning. Some points to be considered in choosing a suitable pump would be the material classification of the pump to withstand the higher static pressure acting on its casing, system design – single pump/system against multiple pumps to cater to different levels of the building, type of control – fixed speed or speed controlled pumps specifically on water supply systems.
It’s a challenge for the designer to strike a balance between first cost and operation cost of such systems. Grundfos customises the system design to suit the customer’s need by having several variants when it comes to hydro pneumatic systems. For high-rises, grouping of the systems are recommended to delineate the effect of static pressure acting on the system. One system for the low zone (low level of the building) and the other for high zone (from 13-24 floors). This reduces the complexity of piping, material selection, pressure rating of valves and fixtures and the control complexity of the system.
As urbanisation drives the increased need for housing, the need for smart and efficient technologies to support growth will become a must. In the case of elevators, this means working with increasingly complex technology. Sebi Joseph, president, Otis India, says, “Last year we introduced the SkyBuild elevator, an internal construction elevator for high-rises that’s now available globally. The unique technology enables the SkyBuild elevator to climb one floor at a time as the building rises. Each jump can be accomplished between shifts, reducing the impact on other trades. And once construction is complete, the SkyBuild elevator goes directly into service as a SkyRise elevator. It gets crews and materials where they need to be quickly and safely, without a crane, without an external lift and without exposure to the weather.” In case of existing elevators, they can be made energy efficient by adding the Variable Frequency Drives (VF drive) in the door system and elevator control system. Otis is also working on developing ‘smart’ elevators.