Boring Deep, Piling High

Charu Bahri reviews the ebbing and rising piling and drilling equipment industry. As the resurgent construction industry ushers in a new wave of optimism, a number of allied sectors look forward to ride piggyback on its success. One of these is the piling and drilling equipment industry, which as Surajit Mukherjee, Managing Director, Suretech Infrastructure Pvt Ltd, observes, has not fully recovered from the slowdown. Even so, Mukherjee notes “The demand for piling equipment did not slow down as much as the other sectors of the construction industry thanks to a certain niche market.” The niche market that sustained the demand for piling and drilling equipment throughout the slow period for Soilmec India, according to Sanjoy Chakraborty, Managing Director, comprised contractors working in the power sector and steel sector, thanks to whom the past 12 months passed off quite well. “These sectors primarily depend on government finance and therefore experienced minimal impact of the slowdown,” he says. DV Brahme, Regional Manager, Mait India Foundation Equipment Pvt Ltd, also points out that while the demand for construction equipment dipped by 60 per cent, the drop in demand for piling rigs did not exceed 20 per cent and that too was largely on account of non-availability of finance. Fortunately, the sustained demand from the industrial and infrastructure sectors compensated for the fall in demand from the real-estate sector. “In fact, for Mait it was a period of consolidation of its market leadership in India,” he says. “In the times when the rest of the world was facing severe recession, our clients have shown their solidarity by placing many repeat orders in the past 12 months in spite of many other new options available. Looking ahead, considering the renewed thrust on infrastructure by the government as well as revival in the areas of industrial activity and realty, we expect the market to grow at 30 to 35 per cent over the coming three to four years. Projects in the eastern part of the country and owners in metros are leading the demand.” A bright future Chakraborty is even more optimistic about the future, saying, “What with all the advanced technologies being brought into the country, I strongly believe that we will emerge as the leading piling equipment company in the local market.” An equally positive projection of the prospects of future growth comes from Mukherjee, who opines, “There are a lot of projects involving piling coming up, such as the Paradip refinery, Transharbour Link project, several metro projects, Mumbai's monorail project and so on. As such, the segment has a bright future and robust growth prospects.” As construction contractors lay greater emphasis on productivity and optimising the use of resources, the construction industry is slowly and steadily adopting advanced construction practices. In this scenario, technology upgrades aimed at enhancing productivity hold the potential to grow every facet of the construction equipment industry, including piling and drilling equipment. In this context, where does India currently stand? The scorecard Has the latest technology available in developed countries made its way to India so as to inspire players in the realty and infrastructure sectors to push the envelope by taking on more ambitious projects requiring deeper piles of greater diameter? Chakraborty observes that the Trevi Group of Italy, Soilmec's global principal, boasts seven decades of experience in the piling industry both as a major contractor and manufacturer. As such, Soilmec/Trevi uses the latest and most advanced technologies for its projects outside India. “Unfortunately though, we have not been able to bring these technologies to India as yet for various reasons, such as outdated local building codes covered under BIS2911 governing the construction of foundations,” he notes. “Consequently, I'd have to say India has yet to reach the required level of sophistication in terms of latest methods and techniques of piling. In India, we have been using only one type of piling equipment, which is called bored piles. Still, we expect a number of techniques and methodologies to be introduced to the country soon.” New technology entrees As part of the process of upgrading technology, Soilmec launched two new products during Excon 2009. “The indigenously manufactured Desander as well as the Soilmec SR-40, upgrades with a pull-down winch,” shares Chakraborty. Speaking of innovative piling or drilling equipment introduced by Suretech Infrastructure in recent months, Mukherjee names the F3500 Fundex Integrated Piling Rig along with the S90 IHC Hydraulic Impact Hammer for cast-in-situ driven piles. “In fact, we ourselves have taken this equipment and rented to a customer to be able to showcase the technology to potential Indian customers,” he explains. “The equipment allows a complete closed bottom pile to be driven up to a depth of 18 m, followed by reinforcement and concreting and extraction of the tube. As a result, the pile is achieved in 30-35 minutes, a far cry from conventional methods that would take hours.” Suretech Infrastructure has also introduced Taets pile breakers to facilitate the efficient and quick breaking of piles leaving the reinforcement intact and Tescar mini piling rigs for doing piles from 400 to 1,000 mm dia for depth up to 22 to 25 m. Overall, Mukherjee believes India is well served by vendors selling and servicing the latest piling equipment, pointing out that Suretech Infrastructure itself represents world-class piling equipment suppliers like ICE BV for vibratory hammers; IHC/Fundex for hydraulic impact hammers and integrated piling rigs; BSP for onshore hydraulic impact hammers; Enteco for piling rigs and diaphragm wall equipment; and STA srl. for vibro floats. Mait has supplied more than 300 world-class piling rigs to clients in India over the past 10 years, during which period Brahme says equipment has been fitted with newer and better technologies to enhance productivity, safety and efficiency as well as meet the latest emission norms. Recently, Mait supplied two drilling rigs to a client in south India for off-shore drilling for a pile foundation. Describing the salient feature of the rig, Brahme says, “It will proceed out to 1.2 km in the sea on an approach road made by the rig itself by piling in the sea bed.” Users' wish-list However, at the other end of the spectrum, users are not as satisfied with the present situation. Expecting the services of the piling/foundation construction and equipment industry to gear up to meet the demands of the country, Dr KS Ramakrishna, General Manager & Head - Foundation & Geotechnical Engineering Cell, L&T, explains, “The recommendations of consultants is skewed towards bored cast-in-situ piling as a result of which most of the piling equipment imported is hydraulic rotary piling rigs. However, there are a number of faster and cheaper piling and other geotechnical systems being practised in the developed world that should be promoted in India so that the piling or foundation industry serves infrastructure development needs in a better manner.” Dr Ramakrishna believes higher capacity equipment should be brought to India to construct deep foundations for tall buildings and other heavily loaded structures. He adds that this requires systematic development of methods and practices to achieve higher productivity and quality using this equipment. Alongside the introduction of new technologies (See Box Futuristic Foundations), he also cites the need to impart continuous training to operators in the right use of equipment, tools and accessories that will go a long way in improving productivity. Vidhu Shekhar, Manager - Purchase, Valecha Engineering Ltd, also notes that while available equipment is of international standards, the foundation industry has yet to develop core competencies and the standard of service could also do with improvement. “The market will only evolve into a major sector when much-awaited new technologies, such as stone column technology, are introduced,” he observes. “In stone column technology, pile holes are filled with stones of a particular nomenclature and size. The material is hammered down either by a piling rig or through a vibratory hammer. The principle is to exert more pressure from the top thereby creating a bond inside the pile hole when the stones exert the same pressure onto the inside walls of the pile hole.” Call of the hour Even until then, contractors are on their part forging ahead with newer methods of piling, varying the equipment they use based on subsoil conditions. For instance, Dr Ramakrishna shares, “We brought in driven cast-in-place piling rigs at our Vadodara and Hazira project sites when others adopted bored piling at the same sites. This provided a cheaper, faster and better quality foundation solution.” And sometimes, contractors vary the attachments used to optimise results. As Vidhushekhar observes, “Minor changes in the attachments used have helped us speed up the progress of piling. We use vibratory hammers instead of the regular piling rigs in hard geographical terrains to penetrate and extract pile liners.” Undoubtedly, as this know-how spreads beyond metro cities, the scope of piling equipment will expand as never before. Focus on foundation technologies According to Dr Ramakrishna, there is no focused approach to implementing advanced foundation technologies in our country probably because the cost of foundations is a very small part of the total civil construction cost of a project. But even in some special cases such as marine structures and bridges, where the foundation costs can be as high as 50 per cent of the cost of the constructed facility, he notes that foundations are still being executed following outdated, slow and labour-intensive methods and equipment. Dr Ramakrishna believes the adoption and implementation of foundation technologies would improve if: • The price of piling equipment is brought down by manufacturing this equipment in India. At present, most equipment is manufactured in Europe and other developed countries. As a result, transportation and customs duty add to already high capital cost, inhibiting procurement of required numbers into our country.• Instead of leaving this important aspect to general contractors who, in turn, expect foundation subcontractors to invest their time and money on the equipment, a national-level forum comprising government, industry and academia needs to be formed to collectively address this issue and pave the way to bring the latest foundation technologies and equipment within a short time frame so our construction industry and our country would benefit immensely.• For wider acceptance of the latest foundation technologies, task force teams need to be formed for each technology, select equipment imported and field trails conducted to demonstrate suitability, and formulate specifications and guidelines for consultants and contractors to follow. This would create demand for modern foundation equipment and methods that would accelerate construction in an economical way.• There is an urgent need to establish training institutes to produce properly trained and certified operators of this sophisticated equipment so the learning curve can be shortened to promote quality and productivity at job sites.• Authorities like the National Highways Authority of India, Delhi Metro Rail Corporation and other client organisations continue to encourage contractors to employ high-productive equipment in their projects. Their initiatives have helped increase the number of hydraulic rotary pilings in the country from nearly zero to more than 500 over the past 10 to 12 years. This number would be at least three to four times larger if all clients and consultants made it mandatory to deploy hydraulic rotary piling rigs for bored piling works in their projects. Service 24×7 Sanjoy Chakraborty, Managing Director, Soilmec India, informs us that the company has introduced new schemes to support customers. “Our equipment is extremely expensive and yet as this is used as production equipment, if it breaks down, production comes to a halt. That's why our present major focus is to give 24-hour support to our customers. We also have a scheme where we provide customers an operational contract where we take care of the machine’s operation, maintenance and spares.” Futuristic Foundations Dr KS Ramakrishna, General Manager & Head - Foundation & Geotechnical Engineering Cell, L&T, suggests the following foundation technologies and materials be widely adopted and implemented in India to speed up construction of projects: • Precast piling with factory-made piles, mechanical pile splices and integrated piling rigs equipped with energy-efficient impact hammers and data logging and monitoring systems• Driven cast-in-situ piling with integrated piling rigs equipped with energy-efficient impact hammers, casing extraction systems and data logging and monitoring systems• Sheet piling, a form of driven piling performed by driving thin interlocking steel sheets into soil to obtain a continuous barrier in the ground. Their most common use is within temporary deep excavations where the retention of higher earth pressures of soft soil is required, in retaining walls and cofferdams erected to facilitate more permanent works• Continuous flight auger (CFA) piling, a rapid and cost-effective open site method of constructing load-bearing and retaining structure piles where the ground is composed of soft rock and/or non-cohesive sands, gravels or silts where otherwise long casings or drilling fluids would be required. Most effective for sensitive sites where it provides a quiet and vibration free piling technique• Deep soil mixing to improve strength of soils in-situ.• Jet grouting, which involves injecting ultra high-pressure fluids or binders into the soil at high velocities to break up the soil structure and mix the soil particles in-situ to create a homogeneous mass, which in turn solidifies to form soilcrete with high strength and low permeability characteristics. This ground modification technique has many applications in foundations, excavations, tunnel support, seepage cut-off walls for dams, etc• Rapid impact compaction (RIC) system to provide controlled impact compaction of the earth-usually a 7 tonne or heavier hydraulic impact hammer is used to impart blows to increase the density of the soil up to a depth of 6 m thereby enhancing the bearing capacity and stiffness of soil• Mass stabilisation with automatic dosing, mixing and monitoring systems of high productivity• Hydraulic pile head breakers, especially for a wide range of concrete piles, both cast-in-place and precast• Screw piles/helical piles, which involve screwing a special type of piles into the ground using either machine-mounted or hand-held hydraulic drill equipment. Helical piles are useful for both tension and compression loads and for transmission towers, anchoring and foundation rafts to overcome uplift forces• Self-compacting concrete for deep foundations, which uses a highly flowable, non-segregating concrete that spreads into place, fills the complete space and encapsulates the reinforcement without any mechanical consolidation• Ground improvement with vibro-compaction (in coarse grained soils)/vibro-replacement (in fine grained soils), which has wide applications to support wide area loads, embankments, control of liquefaction, etc. It is a faster and cheaper method either to replace and/or provide additional support to deep foundations• Diaphragm walls with Kelly/mechanical/hydraulic grabs/trench cutter or equivalent, with slurry handling/separation systems, concrete batching plant• Modern testing systems for integrity and load-carrying capacity of piles, ex., pile integrity (PIT), cross-hole, pile driving analyser (PDA), embedded load cell systems, etc.According to Dr Ramakrishna, equipment plays a crucial role in any special foundation construction and it is not possible to implement the above technologies without the help of modern equipment, methods, data logging and monitoring systems.