Dr Himanshu M Raje, Director, Raje Consultants speaks to SHUBHANGI BIDWE about his experiences and challenges.
He has high ambitions for both his company and country. The driving force behind Raje Structural Consultants, Dr Himanshu M Raje's first project was a factory building for ACC in Bilaspur, Himachal Pradesh, where he executed dynamic parameters for various machine foundations and tall chimneys of 90 m. After his second project, which involved the development of the existing ground for IFCO factory in Kandla through sand drains technology and preloading, Raje designed well foundations and pre-stressed bridges in Mumbai, Mangalore fertiliser project with Toyo, and electrical substation projects in Iraq. He was also involved in the King Khaled International Airport and Al Riyadh, Al Majma'ah and Al Qasim expressway projects in Saudi Arabia. The structural engineer shares his experiences and views on the industry with CW...
On home ground
The completion of my overseas projects led me back to India for the Palm Beach Expressway project for CIDCO. Originally built on marine clay, it was strengthened with preloading systems and settlement analysis. Today, it is one of the best roads with no repairs in the past 10 to 15 years. After a doctorate thesis on recycled coarse and recycled fine aggregate concrete, my first assignment included repair works for buildings damaged during the Gujarat earthquake. I also designed many multi-storeyed structures, college campuses, five-star hotels and townships in the state. The first real challenge included the International Exhibition Centre project in Surat with 90 m span on black cotton soil. This was followed by a five-star hotel in Powai for Rajesh Leisure Hotels. We are now developing a pencil-type structure with a slenderness ratio of 12 in Dadar.
In the olden days, the minimum available grade of concrete was M15; nowadays, for high-rise towers up to 80 storeys, we use high grade concrete upto M100. We use software such as STAAD, SAP, SAFE and ETAB's systems in our projects along with manual calculations. The availability of new materials such as fibre wrapping and laminates has eased repairs of new and old buildings. We are using low-viscosity grouts to repair the fire damaged structure for the Maharashtra Government Secretariat in Mumbai.
These grouts injected or brush applied on porous slabs help them to solidify, in turn strengthening the structure. Columns badly damaged can be repaired with micro concrete along with fibre wrapping. These materials also increase the structure's load carrying capacity. As this is a 60-year-old design, fibre warp technology has been used at nodal joints. Additionally, certain slabs were to take additional load, so we used laminates. Also, there are a number of non-destructive tests available today; unfortunately, the necessary knowledge to conduct them is lacking.
Geotechnically, Northeast India, especially West Bengal, has the worst soil; it is treacherous because of the presence of coal mines. The black cotton soil in Gujarat and interiors of Maharashtra is also deadly. It can cause structures with differential settlements, leading to the collapse of the building or failure of walls. An example is Jhagadia Industrial Estate, where the floors are settling down.
The best solution is to either treat the black cotton soil or remove a part of it and opt for geotextiles or geomembranes. Pile integrity and pile dynamic test are essential for ascertaining quality of piles and load carrying capacity. For deep excavations of basements, shore piling design in multi-storeyed buildings in Mumbai can fail owing to lack of proper control at site or increase of depth of the excavation.
Need to evolve
Heritage structures are generally repaired by adding extra steel columns. Although this maintains the elevation of the structure, it destroys the internal structure completely. Being involved in the repair of buildings such as The Times of India office building and the Maharaja of Baroda's palace, I noticed that heritage design is modified due to lack of understanding of jack arch floors, etc. Vertical construction is the need of the day, if you want to convert Mumbai into Shanghai. Quality control is absolutely necessary. In India, people aim for beautiful interiors but often forget to maintain the quality of the RCC frame, the column, beam, slab, shear walls, which can make them durable. Today, there are chemicals available that can retard corrosion by 20-25 years.
A brighter future
Structural, geotechnical and environmental engineering all have a great future. We need to reduce our dependence on foreign consultants and have more faith in our own engineers. Also, we need more market-oriented subjects.
I am also against the system of oral examinations as these eventually become a tool in the hands of the internal professors and are often misused to promote undeserving students. Due to my previous field experience then academic as Professor and Principal, I have been continuously urging whenever I am on the Board of Studies to allow professors to work with a consultant during their vacations. This will give them practical knowledge to project to their students.
In future, I want to further develop my company enabling various engineering fields under one umbrella. I would also like more Indians to work in overseas projects. The system needs to become transparent so that even a common man can become a consultant and do great work.
TRACK RECORD: HM Raje
• BE (Civil), Mumbai University: 1979
• ME (Structures), Mumbai University: 1983
• PhD (Structures), Indian Institute of Technology (Mumbai): 2000
• KR Datye, Soil Consultant: 1978-1980
• Structural Design Engineer, Toyo Engineering: 1980-1981
• Project Manager, ARTEC: 1984-1987
• I/C Principal, Shah and Anchor Engineering College: 1987-1989
• HOD Civil Department, Datta Meghe College of Engineering: 1989-1996
• Director, HM Raje Structural Consultants: 1997 to date
Project: Hotel Radisson Blu, Powai, Mumbai
Period: Started 2006
Cost: About Rs 400 crore
Client: Rajesh Business & Leisure Hotels
Unique features: This 144 m building stands on four mega columns with a standing height of 50 m and over 23 floors. Its 375 guest rooms have been constructed with floating columns.
Challenges: As the entrance floor was at a height of about 50 m from the original ground floor and about 60 m from the basement, we designed two free-standing columns with spacing of about 35-40 m, placed a girder beam on it and constructed a floating system. Additionally, we used ice cold water for mass concreting of 3,000 cu m in the raft. We also inserted strain gauges in the girder beam to enable us to record the shear force, bending moments and deflections of the girder beam in situ and check with theoretical calculation.
Project : International Exhibition Centre, Surat
Cost: Rs 34 crore
Client: South Gujarat Chamber of Commerce
Unique features: A 90 m structure, column free structure. The total area was 122,000 sq ft, we had to design a 90 m free span for it. Its 18 m central rise enabled all utilities to pass through those particular beams with two tonne chandeliers at a spacing.
Challenges: Developed with black cotton soil, this project needed band drains, which would have costed about Rs 3 crore and a time period of nine months. Alternate scheme was suggested to remove the black cotton soil for about 2 m and refill with regular earth soil with geotextiles and granular-base material. This enabled us to achieve a safe bearing capacity of about 30 tonne per sq m. We completed the entire structure in 10 months.
Project : Richa J Class, Dadar, Mumbai
Cost: About Rs 300 crore
Client: Richa India Infra Development
Unique features: This is a redevelopment project on a narrow strip with single luxury flats per floor. As such a slender length can cause problems in wind analysis, we are using outrigger systems for the first time in Mumbai.
Challenges: As this is a pencil-shaped tower with a slenderness ratio of 12, height 240 m, the column locations had to be aligned to accommodate existing shops at the ground and parking at podium floors. Additionally, outriggers have been provided at two locations to control time period.
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