Synopsis: Forced vibration tests were conducted as per IS 5249 at a site in north-western Rajasthan. The soil at the site are meta-stable aeolian sands, piled up in the form of sand dunes. The test results indicate that, at shallow depths, in the loose to medium dense sands which are in the unstable part of the dune, the response under dynamic loading is poor. The two peaks in the amplitude-versus frequency curve suggest that the soil structure was probably collapsing and the sands were re-arranging into a more compact state. Tests were also conducted on the deeper relatively more stable soils. The test results were effectively used to design dynamically loaded foundations.

Citation : Ravi Sundaram and Sanjay Gupta (1995), “Dynamic Characteristics of Collapsible Aeolian Sands”, Proceedings, Indian Geotechnical Conference, IGC-95 Bangalore, pp 387-389.

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Synopsis: The advantage of small diameter reamed stone columns is that they can be installed using simple augers and a small compaction winch. Thus, rammed stone columns may often work out as a cheaper alternative to pile foundations. It can cause substantial reduction in foundation settlement, thus making it an effective ground improvement technique. The paper illustrates use of the technique for improving performance of foundations on loose alluvial sands. Case studies from two sites are presented wherein the sands to about 3 to 5 m depth were loose in condition; hence the allowable bearing pressure for the specified settlement was very low. Rammed stone columns of 300mm diameter and 5 to 6 m length were installed which successfully improved the allowable bearing pressure for open foundations by reducing settlements. Plate load tests using a 1m square test plate have been used to demonstrate the efficacy of the method. The spacing between the stone columns can be adjusted and optimized to match the loading conditions and extent of improvement desired.

Citation :  Ravi Sundaram and Sanjay Gupta (1994), “Small Diameter Rammed Stone Columns in Fine Sands”, Proceedings, Indian Geotechnical Conference, IGC-94 Warangal, pp 345-348.

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Abstract: The shfting of course of the Yamuna River at Agra by over 800 m during the last four years had threatedned the stabililty of transmission towers of a 220 KV - transmission line on the river bank. After last year\'s monsoons, the river had shifted dangerously close to the existing towers.\n \nCengrs Geotechnica Pvt. Ltd. was awarded the design and construction contract for providing deep pile foundations for the towers that extended below the level of maximum scour. In order to ensure minimum disruption of poer supply, the new towers were first installed and then charged, after which teh existing towers were dismantlled.

Citation : Sanjay Gupta and Ravi Sundaram (1994), “Pile Foundations Save Transmission Towers at Agra”, Civil Engineering and Civil Construction Review, August, 1994, pp 45-46.

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Synopsis: Modern foundation engineering can come to the rescue of structures that have experienced significant foundation distress or failure. Detailed investigation of cause and mode of failure together with careful planning and sound engineering practice is the key to successful execution of the foundation strengthening process. Specific case histories of some projects in Delhi and Bihar are described explaining the nature of foundation distress and methodology adopted to stabilize the structures and ensuring adequate foundation performance.

Citation : Sanjay Gupta and Ravi Sundaram (1992), “Recent Trends in Foundation Strengthening”, Civil Engineering and Civil Construction Review, October, 1992, pp 31-33.

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Synopsis : The evaluation of capacity of offshore piles should be a continual process. After the pile capacity has been computed in the design office, the capacities should be verified and re-evaluated in the field using dynamic pile monitoring techniques. The design should allow for revising the pile capacity based on a detailed study of the driving data. A database of offshore pile installation experience should be accumulated so as to advance the state-of-the-art in the Indian offshore areas.

Citation : Ravi Sundaram and Niaz Ahmad (1986), “How Best Can One Estimate the Load Carrying Capacity of Piles Which Support Offshore Structures”, Proceedings, Indian Geotechnical Conference, IGC-1986, Response Paper Vol.II, 183-186.

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Synopsis: This paper discusses situations where under-reamed pile foundations have been effectively used and found to be superior to other foundation types. The use of under-reamed piles, which are conventionally considered suitable for expansive clays, have been extended effectively over the past several years to the other soil conditions also. The use of these piles is largely a function of economy, time factors, site constraints etc. Some of the projects in Delhi and other areas where under-reamed piles have been used are discussed in brief.

Citation : Sanjay Gupta (1986), “For which Soil Conditions are Under-Reamed Pile Foundations Superior to Other Foundation Systems”, Proceedings, Indian Geotechnical Conference, IGC-1986, Synthesis Paper Vol.III pp 97-101.

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Brief:Modern Foundation engineering can come to rescue of structures that have experienced signinficant foundation distress or failure.Detailed investigation of cause and mode of failure together with careful planning and sound engineering practice is the key to successful execution of the foundation strengthening process.Specific case histories of some projects in Delhi and Bihar are described explaining the nature of foundation distress and methodology adopted to stabilize the structures and ensuring adequate foundation Performance.

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Brief:The shifting of course of the Yamuna River at Agra by over 800 m during the last four years had threatened the stability of transmission towers of a 220 KV-tansmission line on the river bank.After last year's monsoons ,the river had shifted dangerously close to the existing towers.

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Brief:A thorough geotechnical investigation is a pre-requisite for a reliable,safe and economical foundation design.It is important that whatever is envisaged at the investigation and design stage should translate into construction that is in sync with the design concepts,assumptions and predicted foundation behaviour.

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At Cengrs Geotechnica Pvt. Ltd., we are committed to leveraging the latest technology to provide precise and reliable geotechnical solutions. In this context, we are thrilled to announce the addition of LiqSVs to our suite of geotechnical analysis tools.

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The Seismic Cone Penetration Test (SCPT or SCPTu) is an advanced hybrid ground investigation technique that integrates the conventional CPT with in-situ measurement of seismic wave velocities in the soil. This approach enables the collection of data that would traditionally require two separate tests, making it both faster and more economical.

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This article presents two case studies from northern India where advanced geotechnical investigation techniques eliminated the need for ground improvement and demonstrated significant economic and time benefits. The conclusion is clear: “data quality is the key driver of efficient foundation design.”

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The bridge collapses in Bihar serve as a stark reminder of the critical role that geotechnical investigations and foundation testing play in infrastructure safety. By prioritizing comprehensive geotechnical assessments, enforcing stringent construction standards, and adopting advanced investigation techniques and testing trends, we can build bridges that stand the test of time, ensuring safety and reliability for generations to come.

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