The ongoing expansion of metro networks in Indian cities has led to an increased emphasis on modernisation, driving significant design advancements and new innovations. Metro facilities have witnessed notable improvements, with several state-of-the-art solutions replacing conventional designs. Sustainability has remained a key consideration in metro station development.
Over the past decade, Pune’s infrastructure has expanded significantly, particularly in suburban areas, with a focus on developing modern IT parks and special economic zones in locations such as Hinjewadi, Kharadi and Magarpatta. This has improved connectivity and enhanced road networks. The city’s metro rail system has established connectivity between key areas through its operational lines. It is further expected to provide a modern, safe and comfortable public transport system for Pimpri-Chinchwad. It also aims to showcase world-class metro stations and well-developed surrounding areas. Furthermore, the construction of the metro has incorporated sustainable practices including water conservation measures and the use of solar energy systems.
Project overview
Some of the key stakeholders in the space are Hafeez Contractor and Shapoorji Pallonji and Company, which have played a significant role in visualising and developing the Pune metro project. The Pune metro stations have been designed with a dual focus on functionality and aesthetics, incorporating cultural elements to reflect the city’s heritage. They also feature locally inspired colors, patterns and designs. Some stations showcase art and motifs inspired by Pune’s history, such as Maratha architecture, cultural festivals and traditional patterns. Further, passenger safety and comfort have been prioritised. The stations are spacious, weather-resistant and built using eco-friendly construction materials. In addition, they are equipped with solar panels and water recycling systems.
Managing specific-design requirements
Some of the innovative design requirements for the project were a leakproof roof, curved shapes with specific designs, a contemporary colour palette, sustainable solutions with eco-friendly attributes like thermal efficiency and ventilation, and solar-compatible roofing solutions.
Meeting these complex requirements required meticulous design detailing and material selection to ensure operational functionality. For this, a premium concealed fixed roofing and cladding solution was deemed the best fit. Signature colours such as copper penny, champagne gold and sky ridge in COLORBOND® steel were selected from the vibrant COLORBOND® steel spectrum series, offering a unique metallic finish for visually striking aesthetics, turning these stations into modern landmark structures. Interestingly, these materials are not only environmentally friendly, but are engineered to withstand harsh weather conditions, offering best-in-class corrosion resistance.
Overcoming challenges with innovative solutions
A key challenge was the selection of the appropriate roof profile to support the building design with an almost flat roof with a mild slope and walls requiring a 100 per cent leak-proof system. To meet these criteria, LYSAGHT KLIP-LOK® 700 by Tata BlueScope Steel, a commonly used advanced roofing profile, was incorporated for its sustainability, durability, aesthetics and leak-proof performance. The KLIP-LOK®700 has 43 mm deep ribs with 233 mm wide pans, ensuring high water-carrying capacity. This profile is suitable for regions with high rainfall intensity, making it ideal for this project. KLIP-LOK®700 was instrumental in supporting the flat roof design with a mild slope with a 100 per cent leakproof system. Most importantly, no lap joints were introduced on the flat portion of the roof, including at the ridge. A single panel was roll-formed and laid without any joints.
Another challenge emerged in overlapping the straight flat roof profile with curved profile while ensuring it is 100 per cent leakproof with an aesthetically curved eave. The LOK-KLIP® System, an innovative clip designed to conceal end laps, incorporated in KLIP-LOK®700, addressed this issue without puncturing any of the sheets. This technique contributed to the building’s seamless look.
Safety considerations were equally paramount in the design process. Taking into account the wind pressure at the property, the roof had to be designed with strict safety measures. While Pune’s wind speed is 39 metres per second, wind pressure calculations incorporated a 100-year factor with enhanced parameters for safer designs. Accordingly, the purlin spacing was reduced to 1,400 mm to meet the design criteria, which ensured structural integrity by offering excellent wind uplift resistance.
Beyond structural challenges, accommodating solar modules introduced another challenge. KLIP-LOK®700 again was proven as an ideal solution ideal as it was best suited to hold the solar modules on the top without puncturing the roof sheets. Furthermore, Tata BlueScope Steel developed special aluminium clamps designed to be mounted on KLIP-LOK®700 profiles with friction bolts, allowing the direct installation of solar modules without puncturing the sheets.
During the construction phase, additional complexities arose from the need for multilevel roofing in blocks, with crimp curves of varying degrees that taper in different directions, posing challenges for conventional design dynamics. This was addressed through precision in detailing by the engineering team of Tata BlueScope Steel. The sheets were installed against each block with different curves using crimp curve drawings carefully aligned with the desired shape. The installation of sheets followed a phased pattern – top layers were installed first, followed by side walls and layer-wise cladding.
Another significant challenge was achieving the proper overlap of curved sheets for a leak-proof and aesthetically seamless installation. To this end, individual curved sheets were meticulously detailed against each block, accounting for different curve shapes across all blocks, eliminating the possibility of errors. Furthermore, on-site crimping was done according to crimp shop drawings, specifically based on the unique shape of each block.
Finally, the disconnected individual roof blocks of one single metro station presented a challenge regarding rainwater management and leak prevention. The solution came in the form of closure flashings, which were strategically installed at the ends of individual blocks to divert the rainwater from the roof to the wall. These flashings also doubled as covers for structural steel elements, effectively safeguarding them from the external environment.
In sum
The successful execution of the Pune metro stations stands as a testament to the successful integration of aesthetics, robust engineering and structural feasibility. This project sets a new benchmark, paving the way for future metro developments across India to incorporate similar essential design aspects.
Over the past few years, many players have entered the space. For instance, Tata BlueScope Steel’s role has been instrumental in the development of metro lines by supplying superior quality roofing and structural solutions for metro stations. The innovative roofing solutions offer design flexibility, exceptional aesthetics and unparalleled structural integrity, while ensuring passenger comfort and safety. In addition, these solutions deliver significant savings on the total cost of ownership.
