Knowledge Center

At Cengrs, one of our core values is sharing of knowledge. Owing to our extensive experience in providing expert Geo-technical engineering services to the construction industry, we have over the years, gained significant knowledge about the key issues and challenges in this domain. To consolidate this valuable learning, we have established a Knowledge Centre, which primarily works on the theology of collating information & experiences, and disseminating it to interested organizations & individuals.

Through case studies and technical papers, our Knowledge Centre aims to serve as an excellent resource for anyone conducting Geo-technical activities. We strongly believe that this knowledge should be constantly refreshed and improved to provide companies with the required guidance & support for enhancing business processes and improving efficiency.

TECHNICAL PAPERS
Building a University on Liquefiable Sands using Dynamic Compaction
Citation:Ravi Sundaram, Sanjay Gupta, Sorabh Gupta(2017), 09-Oct-2017

Abstract :A major University project spanning 511 acres with a total constructed area of 357 acres has recently been constructed in the state of Uttar Pradesh in North India.

Loose to medium dense ‘clean’ Yamuna sands belonging to the “Indo-Gangetic Alluvium” were encountered at the project site, which were found to be susceptible to liquefaction to about 8-12 m depth. To avoid the difficulties and high costs associated with high-quality soil sampling and advanced laboratory testing for determination of cyclic resistance ratio (CRR), field tests consisting of standard penetration tests (SPT) and cone penetration tests (CPT) were carried out.

Citation:Ravi Sundaram, Sanjay Gupta, Sorabh Gupta(2017),"Building a University on Liquefiable Sands using Dynamic Compaction",9th International Conference on Soil Mechanics and Geotechnical Engineering (ICSMGE 2017)(17 to 22 September 2017), Seoul, Republic of Korea

Building a Mega Power Plant on Liquefiable Sands- A Case Study
Sanjay Gupta, Ravi Sundaram, Sorabh Gupta, 14-Aug-2016

Abstract : Geotechnical investigation for a major power plant in Punjab indicated the likelihood of liquefaction of the loose sands to about 7.5-11 m depth. To mitigate the liquefaction potential, ground improvement by vibro-compaction was done for the light to medium loaded facilities. Piles extending well below the liquefiable zone were used to support heavily loaded facilities. The paper presents data and analysis for the Boiler-I area where ground improvement was done successfully done and raft foundation for the raft was provided.

Citation : Sanjay Gupta, Ravi Sundaram, Sorabh Gupta (2012), “Building A Mega Power Plant On Liquefiable Sands – A Case Study”, Proceedings of Indian Geotechnical Conference (December 13-15, 2012), Delhi, Page 428 to 431.

Current Trends IN Geotechnical Investigation Techniques
Sorabh Gupta, Ravi Sundaram, Sanjay Gupta, 08-Apr-2016

Abstract : The new emerging trend in modern geotechnical investigation is to place a greater emphasis on in-situ tests. These tests can be effectively used to predict foundation behaviour with a higher factor of reliability. The paper presents four different types of advanced in-situ testing techniques with three case histories to demonstrate effective use of such advanced in-situ tests – static cone penetration tests, pressuremeter tests, geophysical tests and aquifer test.

Citation : Sorabh Gupta, Ravi Sundaram, Sanjay Gupta (2016), “Current Trends in Geotechnical Investigation Techniques”, AGE-2016, National Conference on Advance Geotechnical Engineer (April 8th-9th April, 2016), Aligarh Muslim University, Aligarh, Pages 37 to 52.

Piles Through Soft Clay For A Metro Project
Ravi Sundaram, Sanjay Gupta, Sorabh Gupta, Abraham V. Varghese, 08-Sep-2016

Abstract : Geotechnical investigation for the Kochi Metro revealed a critical section of the Viaduct near Ernakulam Junction Railway Station. Four piers, located over a 220 m stretch, were passing through an area with substantial thickness of soft clay. The scope of the geotechnical investigation included two boreholes and a static cone penetration test at each pier location. In the boreholes, field vane shear test was conducted at different depths in addition to the routine SPT. The design of heavily loaded piles in such strata is a challenge due to the liquefaction of the shallow sands and negative skin friction / down-drag in the soft under-consolidated clay. Bored cast-in-situ piles of 1500 mm diameter extending to 50-60 m depth were used to carry 500-600 tonnes load.

Citation :Ravi Sundaram, Sanjay Gupta, Sorabh Gupta, Abraham V. Varghese (2016), “Piles Through Soft Clay For A Metro Project ”, Proceedings, DFI India 2016: 6th International Conference on Deep Foundation Technologies for Infrastructure Development in India(September 8-10,2016), Shibpur, Kolkata 

In-situ Testing to Verify Ground Improvement
Mr. Ravi Sundaram & Mr. Sanjay Gupta, 20-Oct-2015

Abstract: Reliability of improvement achieved is the key to the implementation of soil stabilization and ground improvement measures. In-situ tests are an essential part of the ground improvement process to confirm that the desired improvement in soil properties has been achieved. The paper presents two case studies in the Delhi-NCR area where ground improvement was done to mitigate liquefaction potential and improve the soil bearing capacity. In-situ tests conducted before and after improvement to verify the effectiveness of improvement include SPT (in boreholes), static cone penetration tests (SCPT) and plate load tests.

Citation: Ravi Sundaram, Sanjay Gupta (2015), “In-Situ Testing to Verify Ground Improvement”, Proceedings, Symposium on “Advances in Instrumentation, Geo-Monitoring and Validation”, 23-24 July, 2015), New Delhi

Ndt Techniques for Determining Depth of Foundations
Sanjay Gupta, Ravi Sundaram, Sorabh Gupta, 17-Dec-2015

Abstract : Evaluating the depth of existing foundations may sometimes be required on construction projects. If original pile records / drawings are not available, it may become difficult to make a rational assessment of the depth of existing foundations. Where the new construction requires knowledge of length of pile / depth of existing foundation, modern NDT techniques such as parallel seismic and sonic echo / impulse response tests can provide useful information.

Citation :Sanjay Gupta, Ravi Sundaram, Sorabh Gupta (2015), “NDT Techniques for Determining Depth of Foundations”, Proceedings of 50th Indian Geotechnical Conference (December 17-19, 2015), Pune, Maharashtra,

Back Analysis of Pile Load Test Results a Case Study
Ravi Sundaram, Sorabh Gupta, 23-Jul-2015

Abstract: Caution is required in selecting the safe load carrying capacity of bored piles, even if a few test piles indicate substantially higher capacity than theoretically estimated from static analysis. The consequences of failure of working piles should be evaluated carefully to select suitable safe load carrying capacity for design. Use of pile capacities higher than the computed values should be backed up by sufficient static and dynamic pile load tests and integrity tests. A case study illustrating static and dynamic load tests on piles installed in alluvial sands demonstrates the design methodology to be followed.

Citation : Ravi Sundaram, Sorabh Gupta (2015), “Back-Analysis Of Pile Load Test Results – A Case Study”, Proceedings, Symposium on “Advances in Instrumentation, Geo-Monitoring and Validation”, 23-24 July, 2015), New Delhi

 

Geotechnical Investigation in Gravel-Boulder Deposits
Sundaram, Sanjay Gupta, 04-Dec-2015

Summary : Geotechnical investigation through gravel-boulder formations poses difficulties due to the problems of drilling in such deposits. Various drilling methods such as percussion, rotary and DTH have been used on projects with different degree of success; a combination of two methods is usually effective. In addition to drilling, geophysical tests and load tests help in better assessing the stratigraphy and selecting suitable values of safe bearing capacities.

Citation : Sundaram, Sanjay Gupta (2016), “Geotechnical Investigation in Gravel-Boulder Deposits”, The Bridge & Structural Engineer, Journal of the Indian National Group of International Association for Bridge and Structural Engineering, B&SE (December, 2015), Volume-45, No. 4.

Building a University on Liquefiable Soils Using Dynamic Compaction
Ravi Sundaram, Sanjay Gupta, Sorabh Gupta, 16-Jul-2014

Abstract :A major University site spanning 511 acres with a total constructed area of 357 acres has recently been constructed in the state of Uttar Pradesh in north India. The campus, once established, shall boast of over 84,000 m2 of constructed area with 30 percent green cover. The site is located in the Yamuna flood plain, about 2 km. from the river.

Citation: Ravi Sundaram, Sanjay Gupta, Sorabh Gupta (2014), “Building a University on Liquefiable Soils Using Dynamic Compaction”, Proceedings of DFI Conference (September 19-20, 2014), Delhi, Page 67.

Identifying Defects in Large Diameter Bored Piles Case Studies
Ravi Sundaram & Sorabh Gupta, 09-Sep-2014

Introduction : Construction of deep bored piles requires adequate quality assurance measures to ensure that the pile is free of major defects and can safely carry the design loads. The paper presents pile quality assurance tests implemented for two case studies of large diameter piles installed in the Indo-Gangetic Alluvium.

Citation : Ravi Sundaram, Sorabh Gupta (2014), “Identifying Defects in Large Diameter Bored Piles – Case Studies”, Proceedings of DFI India Conference (September 19-20, 2014), Delhi Page 44

Article in Indian Infrastructure Magazine, Special Section:Foundation and Piling Works
Sanjay Gupta et. al., 13-Sep-2012
Introduction :If the Twelfth Plan (2012-17) estimates of Over $1 trillion investment in infrastructure development fructify, it will present an enormous opportunity for the construction industry, and specifically for foundation and piling works. Construction is critical to infrastructure project development and, typically, 5 per cent or more of the cost of any civil engineering project in India is contributed by foundations and piling. The key market segments for foundation and piling works include roads and highways, power plants, marine structures, metro rail projcts, oil refineries, wate and stormwater drainage projects, airports, and comercial buildings and housing projects. \n\nThe Indian piling equipment market is estimated to be worth Rs.2 billion. The market has grown at a rate of about 20-25 per cent in the last few years, spurred by infrastructure development. However, the Indian market is still considered to be nascent and it is estimated that only about 200 piling-rela
Quality Assurance for Deep Bored Piles A Case Study
Sanjay Gupta, Ravi Sundaram, Sorabh Gupta, 16-Aug-2012

Abstract : One of India’s tallest residential towers is being constructed in the state of Uttar Pradesh, not very far from the YamunaRiver. The development includes the construction of a 66-story residential tower rising about 240 meters above grade and having two basements extending about 9 meters below grade. The foundation system for the proposed development consists of a piled-raft system with a 2.5-meter thick reinforced raft, supported by 298 Nos. bored-cast-in-situ piles of 1 m diameter and 48 m depth. This paper describes the geotechnical investigations carried out at the project site to estimate the safe pile capacities, and presents the results of a rigorous quality assurance program executed by the authors to ensure foundation quality and performance in-situ.

Citation : Sanjay Gupta, Ravi Sundaram, Sorabh Gupta (2012), “Quality Assurance for Deep Bored Piles–A Case Study”, Proceedings of Indian Geotechnical Conference (December 13-15, 2012), Delhi Page 608 to 611.

 

Geotechnical Characterization Of Soft Clays Of The Godavari Delta
Sanjay Gupta, Ravi Sundaram, Sorabh Gupta, 22-Oct-2011

Abstract : Soft under-consolidated clay is encountered to substantial depth in the Godavari Delta of coastal Andhra Pradesh. Constructing foundations in such weak deposits needs careful assessment of the geotechnical properties. This paper presents details of geotechnical investigations carried out for an onshore gas terminal project in such strata, an evaluation of the ground improvement methods employed at the site, and details of the selection and testing of the foundation system adopted for statically and dynamically-loaded facilities.

Citation :  Sanjay Gupta, Ravi Sundaram, Sorabh Gupta (2011), “Geotechnical Characterization Of Soft Clays Of The Godavari Delta”, Proceedings, Indian Geotechnical Conference (IGC, Dec-15-17, 2011), Kochi, pp 166 to 169.

Liquefaction Risk Mitigation for a Power Plant in the Indo-Gangetic Alluvium
Sanjay Gupta, Ravi Sundaram, Sorabh Gupta, 27-Oct-2011

Abstract : The paper presents the case study of liquefaction studies for an upcoming power plant in the Indo-Gangetic plain. Geotechnical site characterization studies suggested that the sands to 8 m depth were prone to liquefaction during the design earthquake. Accordingly, TG, chimney and other heavily-loaded facilities were supported on piles extending well below the liquefiable zone. Ground improvement by vibro-replacement was done in other areas of the site to mitigate the liquefaction potential.

Citation :Sanjay Gupta, Ravi Sundaram, (2011), “Liquefaction Risk Mitigation for a Power Plant in the Indo-Gangetic Alluvium”, Proceedings, The 14th Asian Regional Conference on Soil Mechanics and Geotechnical Engineering Hong Kong, China (May-2011), Page 306.

 

Constructing Foundations On Red Mud
Ravi Sundaram & Sanjay Gupta, 02-Nov-2010

Introduction : Red mud is a waste product of the aluminium industry formed by washing and purifying bauxite (aluminium ore). It is pumped in slurry form into a disposal pond. Over a period of time, as the water partly seeps into the ground and partly evaporates. The red mud slurry thickens to form a soft deposit with very low SPT values.

The paper shall present the case study of an industrial structure (drum filter plant of the aluminium plant) constructed on a thick red mud deposit. Since the red mud behaves like very soft clay with SPT values in the range of 1 to 5, ground improvement was done by provision of rammed stone columns. This resulted in substantial savings to the owner in comparison to the cost for installing concrete piles.

Citation : Ravi Sundaram and Sanjay Gupta (2010), “Construction Foundations on Red Mud, Proceedings, 6th International Congress on Environmental Geotechnics, New Delhi, Volume-II, pp 1172-1175.

ARTICLES
Recent Trend In Foundation Strengthening
Sanjay Gupta,Ravi Sundaram, 01-Oct-2017

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.

Pile Foundations Save Transmission Towers At Agra
Sanjay Gupta,Ravi Sundaram, 06-Sep-2017

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.

Geotechnical Investigations - The Way Forward
Sanjay Gupta,Ravi Sundaram, 19-Sep-2017

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.