Building at Sea

Numerous port and harbour development projects getting underway are improving the range of equipment available for construction activities, says Charu Bahri.Today, it's undoubtedly swim, not sink, for vendors of port construction equipment! The huge investments proposed by the National Maritime Development Programme to shore up the country's port infrastructure have considerably improved their prospects. With 276 projects aiming to expand the capacity of the country's 13 major ports to 800 million tonne by FY12, necessitating investments of Rs 558 billion, more vendors are expected to cash in on the emerging opportunities. As Vishwesha Bhat, CEO, Ports & Jetties Business Vertical, Essar Projects (I) Ltd, observes, Port construction activities entail a wide range of equipment, including marine crafts, jack-up barges, tugs and anchor handling vessels, barges of all kinds, cranes, piling rigs, drilling, blasting, and transportation equipment.Survey equipmentSurveys are an essential port pre-construction activity. Appropriate subsea surveys generate information that allows designs to take into account the existing subsea environment, including structures such as paleo-channels and weathered and un-weathered rock outcrops. Quantitative data pertains to the depth and density of sub-bottom structures while qualitative data relates to the quality of observed structures. By generating a complete picture of the sub-bottom profile, geophysical profiling systems help fine-tune specifications of a project to match existing conditions, reduce dredging and construction costs, and minimise budget variations.At present, subsea survey equipment such as that used for refraction surveys to map the subsea strata with reasonable accuracy is generally imported, observes SV Rajadhyaksha, CEO, Leighton Welspun Contractors Pvt Ltd. Similarly, jack-up platforms, which could work in stringent environmental conditions, in deeper waters or for geotechnical investigation works as well as construction, are required to be imported. Also, marine survey vessels capable of working in adverse environmental conditions with adequate anchoring and the full spectrum of marine geotechnical and geophysical survey capabilities are in short supply.It is true that all high-end survey equipment, such as sub-bottom profilers, side scan sonars, echosounders, current metres, tide recorders and wave rider buoys, are to be imported, says Dr P Chandramohan, Managing Director, Indomer Coastal Hydraulics Pvt Ltd, (Chennai), which has conducted surveys for ports like Gopalpur, Machilipatnam and Krishnapatnam. But you also need specialists to operate the equipment and interpret data. Also, this equipment becomes obsolete after a few years and needs to be replaced. Therefore, it is not cost-effective for a developer with a single project in hand to make such a huge investment. Nowadays, developers of ports and harbours as well as oil and gas pipelines are encouraging private survey companies in India to procure and establish a strong infrastructural setup for taking up their surveys.Hammers for offshore usesSuretech Infrastructure has supplied vibratory and impact hammers for marine applications and ports and jetties, such as projects at the Paradip Port, Adani Port, Krishnapattnam Port, Kakinada Port, Mangalore Port and Egmore Port. ICE hydraulic vibratory hammers are used to drive and extract heet piles and casings where the soil has N values of less than 50. ICE has developed a predictability programme to help clients select the most suitable hammer for their requirements. It has also developed ICE power packs that can be combined with vibratory hammers, impact hammers, augers, winches, dredge pumps, demolition hammers, crushers, breakers or hydraulic cylinders, to increase the efficiency and drive flow of the power pack and reduce fuel consumption. Surajit Mukherjee, Managing Director, Suretech Infrastructure Pvt Ltd, says, We achieved equipment sales of nearly Rs 100 crore last financial year, and we expect to grow by 20 per cent this year.Suretech also supplies BSP hydraulic impact hammers for driving casings, pre-cast concrete piles, cast-in-situ piles, and sheet piles and IHC hydraulic impact hammers for offshore and rock-breaking, raked piles and underwater operations. Taets Techniek pile breakers are on offer as well, for trimming concrete foundation piles of any shape: square, hexagonal, octagonal and circular.Piling rigs: contractorspeakPiling equipment is mainly used for the construction of port jetties. Jetties used for berthing ships require large diameter piles. According to Dr P V Chandramohan, President - Technical, Navayuga Engineering Company, Most large diameter piles in India are the bored cast-in-situ type installed using either a rotary drilling rig or bailer and chisel. Alternatively, they could be very expensive steel piles that are not the norm in our country. Rotary drilling rigs are expensive but very fast. But these are not manufactured in India; they are imported from Germany, Italy or China.Marine pile driving equipment, like heavy duty hydraulic impact hammers, of adequate capacities and capable of boring into rock strata is generally difficult to find locally, adds Rajadhyaksha. Thus, the industry resorts to conventional hammers and chiselling using locally made bailers and chisels. But this is extremely time-consuming and unproductive.Chandramohan sees scope for Indian equipment companies to design and manufacture rotary drilling rigs locally. This would shorten the project execution timeline as well as improve the servicing of the rigs and ensure that spares are locally available. Fortunately, both light (to carry bailers and chisels) and heavy duty gantries (that can carry heavier rotary drilling rigs) are being fabricated in the country.Piling rigs: vendorspeakAccording to Nitin Jajal, General Manager, Mait India, There are no gaps in after-sales services and expertise being offered to clients in spite of rigs being imported. In fact, we have to maintain a high level of spares inventory to ensure minimum downtime. MAIT HR Series hydraulic rotary rigs are extremely versatile and are being put to good use by Indian contractors for marine and port jobs. Other than being used to shore piles, they are also being mounted on jack-up barges and gantries. Two MAIT HR180 rigs are being used to drill 1,200 mm diameter piles to a depth of 58 m by Geo Foundations at L&T ECC's shipbuilding facility site in South India. MAIT rigs have also been used to speed up marine pile foundation jobs at the Pipavav, Katupally, Dahej and Krishnapatnam ports.Recently, Suretech introduced IHC Fundex driven cast-in-situ heavy duty integrated piling rigs to the Indian market. Three such units are working with KazStroyService Infrastructure India Pvt Ltd and Valecha Engineering Ltd at Paradip IOCL Project. If the reinforcement and concrete are appropriately supplied to this machine, it can achieve more than 20 piles per day. Proper logistics allowed the machine in Paradip to achieve 29 piles per day, shares Mukherjee. Also, Suretech recently became a dealer for Sany Beijing for its range of rotary piling rigs. Sany is the largest producer of piling rigs in the world with an annual capacity of over 1,500 rigs per year and an installed base of over 32 rigs in India.Diaphragm wall technologyPort and harbour works involving the construction of berths and new and extended jetties also necessitate diaphragm wall technology, creating a huge market for equipment facilitating such marine foundations. With over 600 port-related projects in the offing, the scope for Casagrande KRC diaphragm wall equipment is huge, says Sreedhara Narayanan, General Manager, Casagrande India. With a local presence in the country, we look forward to tapping emerging opportunities by offering Indian contractors advanced technology and a wide range of equipment, including custom-made solutions to suit the demand for all kinds of geotechnical engineering. Already, companies such as SVC Projects and Navayuga Engineering Company Ltd have used Casagrande KRC complete diaphragm wall systems for the DGNP project in Visakhapatnam (for the construction of the jetty) and Nellore and Ennore port projects respectively.MAIT rigs are also being used to construct diaphragm walls up to 32 m depth at ABG Shipyard in Dahej by ITD Cementation, adds Jajal.Cranes and bargesAncillary equipment such as cranes and winches are available in plenty in the country. Crawler cranes are especially of use in marine structures, for the construction of quays, berths and marine walkways. Crawler cranes can position large rock elements in a sea barrier and set pre-cast concrete elements for the construction of the port's quay wall. They can also work offshore on pontoons or jack-up barges, from where they can help install piles. According to Prem Naithani, National Sales Manager, Manitowoc Crawler Cranes, India, A few Indian ports are using Manitowoc crawler cranes such as the 4100 and 4000 models for port operations. We've recently been getting a number of enquiries from port operators for our 400 tonne Model 16000 crawler cranes too, which are being used overseas for port construction activities.Barges of all kinds are vital for port construction activities. Simple barges play numerous roles while specialised kinds like jack-ups come in handy for piling, split hopper barges for dredging in harbour, and likewise. Even batching plants are mounted on barges in order to ensure the high quality of concrete to far shore structures. According to Bhat, The scope for barge fabricators is huge. Still, though there is no dearth of fabricators, the process is a bit slow in India. As contractors and developers working on tight timelines cannot afford to wait, they prefer to import these barges. Also, the hydraulic systems of advanced and specialised barges are of better quality than what are locally available.Dredging equipmentCapital dredging refers to the process of removing virgin soil to create the designed depth in the water body. Such dredging projects are usually large. In contrast, maintenance dredging refers to removal of sediments that accumulate over time owi-ng to littoral drift, underwater currents, and wave and tidal actions. Maintenance dredging restores the depth of ports and harbours to its designed navigable level for the safe entry and exit of ships.As far as dredging equipment is concerned, JP Awasthi, Senior Vice-President, Continental Construction Corp Ltd, observes, The choice depends on the volume of work entailed. Maintenance dredging could be done with bucket chain or grab type dredgers while capital dredging projects necessitate cutter section dredging equipment.Suitable effective 'rock trench-ing/dredging' equipment still needs to be imported, observes Rajadhyaksha. Mobilising equipment from overseas at a higher cost defeats its economic competence. Fortunately, cutter suction dredgers are available in India and there is a marked improvement in their operative efficiency.Hopefully, as more projects are unveiled, developers and contractors will continue to see improvements in the range of equipment available and operational efficiencies.To share your views on India's port infrastructure, write in at feedback@ASAPPmedia.com