Concrete

Optimisation of Concrete Cost for Metro Projects

Published

7 years ago

June 30, 2018

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An attempt is made to develop a systematic approach for estimating the quantity of concrete and optimisation of concrete cost based on a case study. The article will be published in two parts. The present article (Part 1) discusses about the Metro Projects in brief, construction methodology adopted, estimation of concrete quantity and associated cost. The next article (Part 2) will be discussing about the methodologies used for optimising the cost associated with production, transportation and placement of concrete.

In India, for infrastructure projects, the concrete is used as one of the essential construction materials. Appropriate selection of concrete (type/grade) and precise estimation of concrete quantity are essential to achieve optimised cost of concrete. Further, optimisation of construction cost related to concrete could also be achieved by appropriate selection of construction methodology along with equipment selection (rental/purchase/outsourcing) suitable for site conditions. various equipment are required for the production, transportation and placing of concrete. The selection and usage of these equipment are crucial for the successful completion of project work. Generally, the selected equipment shall fulfill project requirements within the timeframe.

In this regard, comprehensive analysis on selection of equipment and their usage in construction site needs to be carried out by the contractor well in advance (i.e bidding stage). If equipment planned to use in construction site is inadequate, it will be difficult to follow the schedule of fast track infrastructure project. On the other hand, to reduce the time period of construction, the plan for excess usage of equipment, may not be financially beneficial for the project. Hence, there is need to develop a systematic method for for optimising the cost of concreting by accurate estimation of concrete quantity and effective decision on selection of appropriate construction systems. The method was developed based on a case study (construction of metro project in Mumbai).

Mumbai Metro project
The master plan for metro project in Mumbai includes nine corridors covering a length of 172 km, out of which 32.50 km is proposed underground and the rest is elevated. First 11.40 km long elevated metro corridor between Versova – Andheri – Ghatkopar (Line 1) is commissioned in June 2014. Elevated corridors between Andheri (East) to Dahisar (East) – 16.475 km (Line 7), Dahisar to DN Nagar – 18.589 km (Line 2A) and underground metro between Colaba – Bandra – SEEPZ is under construction. Construction of elevated corridor between DN Nagar to Mandale (Line 2B) is about to start. After implementation of the Mumbai metro master plan, 70 lakh commuters are expected to get benefit, in turn, will reduce the traffic on roads and congestion in suburban rails.
1.1. The metro line 2A is selected as a case study for the present article. Brief scope of elevated metro project is as follows:

Viaduct: Design and construction of around 18 km elevated viaduct including viaduct and ramp for depot entry.

Stations: Design of 16 elevated stations (excluding architectural finishing and pre-engineered steel roof

structure).

Construction methodology: Construction methodology of a metro project is explained in this section. Civil construction activities includes mainly two pases, i.e., construction along the alignment and construction of precast elements at casting yard.

Construction along the alignment (route of metro line): Key construction activities along the alignment are as follows:

Barricading is provided to enclose the construction area to ensure safety and coordinated movement of vehicular and pedestrian traffic (Fig. 1).

Pile locations are accurately marked on ground by using the total station. Pilot trenches are made to check for any infringing underground utilities. If utilities are found, they are shifted for hassle free construction. To initiate the piling work, hydraulic rotary piling rig is positioned at piling location for boring of the pile (Fig. 2). While boring, temporary casing is provided up to required depth depending on the ground strata. After completion of boring, reinforcement cage is lowered. For casting of pile, the tremie pipe is lowered and concrete is poured up to required level through the tremie pipe.

After completion of group of piles for one pier, excavation of the pile cap is taken up. After laying PCC, the reinforcement cage is tied and concreting of pile cap is done.

After tying reinforcement for pier, the starter is cast. After casting the starter, balance formwork is erected for casting pier. Concrete will be placed up to bottom of pier cap using the truck mounted boom placer (Fig. 3 and Fig. 4). At the end, anti-crash barrier is cast.

Precast pier cap from casting yard is transported to the site and erected on pier by using the crane (Fig. 5 and Fig. 6).

"Stitch concrete" (Fig. 7) of pier cap (junction of pier reinforcement and pier cap reinforcement) is done by using the crane and bucket.

First stage stressing of pier cap is done. Bearing pedestals are cast using crane and bucket. For curing of bearing pedestals, curing compound can be used.

Precast "U" girder from the casting yard is transported to the site using multi-axle hydraulic trailer. The girder is placed on bearing pedestal using high capacity cranes (Fig. 8).

After erection of girders in the adjoining spans, second stage stressing of pier cap is done.

Construction of station building by combination of precast and cast in-situ concrete is done at each station location (Fig. 9).
Casting yard: Casting yard is mainly utilised for casting of the precast elements (pier caps, "U" girder, "I" girders, etc.), which are transported to the desired location along alignment for erection. Key construction activities at the casting yard are as follows:

Development of infrastructure at casting yard is very important activity. This includes the RMC plant installation, stacking of materials for RMC plant, construction of casting beds for precast piers, "U: girders and "I" girders, arrangement for stressing activity at each casting bed, stacking beds for casted precast elements and shed / gantry for handling formwork and casted precast elements (Fig. 10 and Fig. 11).

For casting of "U" girders, first cleaned bottom and outside shutters are placed in positioned and aligned properly. Thereafter, the reinforcement cage is placed in position. Inside shutters are placed after placing reinforcement and high tensile steel wires. Stressing of strands is done before casting "U" girders (Fig. 12 and Fig. 13).

Concreting of girder is done by using the placer boom. After achieving desired concrete strength, girders are shifted on the stacking beds (Fig. 14).

Casting of precast pier cap is done at the casting beds of pier cap. Truck mounted boom placer is used for placing concrete. After achieving desired concrete strength, piercaps are shifted on stacking beds (Fig. 15 and Fig. 16).
Estimation of concrete quantity
Based on the project, the required concrete quantity for viaduct and station needs to be calculated.. The estimated concrete quantity forms the base for calculating the cost of concrete and associated optimisation. Total concrete quantity at a glance for the selected project.

The cost associated with the concrete production and placement shall be estimated based on the following categories. Materials cost – depends on various grades of the concrete and the required quantity in each grade.

Plant and machineries cost – depends on the duration of project and the total concrete quantity required.

Transportation cost – depends on the location wise concrete requirement (at casting yard and/or along alignment).

Placement of concrete cost – Based on the site requirement, the concrete placement method (pumping/placer boom/bucket) needs to be planned for various concrete structures.

Details about planning and costing of above points are explained in subsequent points.

Costing of concrete

Concrete using fly ash/ground granulated blast furnace slag (GGBS) along with 53 Grade Ordinary Portland Cement (OPC) has been considered in calculation of cost.

Following are the possible technical advantages of using fly ash/GGBS along with OPC :

Diameter of viaduct pier is 1.8 m. In case of usage of only OPC, the core temperature of concrete may be higher and there are chances of thermal gradient leading to cracks within mass of concrete piers. Usage of fly ash will reduce the heat evolution during hydration, leading to reduced core temperature.

If high grade concrete is produced using only OPC, cement content in concrete increases. This may lead to shrinkage of concrete. Use of fly ash may minimise the shrinkage cracks.

In case of use of fly ash/GGBS, there will be secondary hydration which will make concrete more impermeable and greatly improve the durability of concrete structure.

Cohesive concrete can be achieved. Further, surface finish of the concrete structure can be improved.

For piles and pile caps, concrete can be produced using 53 grade OPC and GGBS.

For mass concrete, up to 70 per cent GGBS of total cementitious materials can also be used. This will be helpful in reducing core temperature of concrete. However, the limits on the percentage replacement shall be specified in the case of pumping.

Average material cost (as received from ready-mix concrete suppliers in Mumbai) for different grades of concrete required in metro construction using OPC and fly ash is given in Table 1. The fly ash is used up to 30 per cent (by mass) in concrete and the percentage replacement varies depending on the grades of concrete.

In case of GGBS usage, there will be further reduction of material cost in the range of Rs 200 to 400 per m3, depending on the grade of concrete and percentage of GGBS used.
Summary
The present article discussed about the metro projects in brief along with construction methodology of an elevated viaduct. Further, the article discussed about the method of estimation of concrete quantity and associated costs for various grades of concrete.
Acknowledgment

Mumbai metro rail projects

Schwing Stetter (India) for information on equipment required for RMC plant

AIMIL Ltd. for providing information on laboratory equipment

RMC suppliers in Mumbai for providing rates of RMC and raw materials
Authors

Mahesh Tendulkar
M.Tech Student
Construction Technology and Management
Department of Civil Engineering
Indian Institute of Technology Bombay
Powai, Mumbai – 400 076.
tendulkar_mahesh@yahoo.com
Basavaraj M B
Chief Engineer (Civil) – Metro
Mumbai Metropolitan Region Development Authority
Old Administrative Building, 6th Floor
Bandra – Kurla Complex, Bandra (East)
Mumbai – 400 051.
basavaraj.mb@mailmmrda.maharashtra.gov.in
Prakash Nanthagopalan
Assistant Professor
Construction Technology and Management
Department of Civil Engineering
Indian Institute of Technology Bombay
Powai, Mumbai – 400 076.
prakashn@civil.iitb.ac.in

Table 1 :Material cost for various grades of concrete

Concrete	Material cost/m3 (in Rs)
M15	3,800
M35	4,550
M40	4,650
M45	5,200
M55	5,600

Concrete

Sambhv Steel Tubes is Now Certified as a Great Place to Work

This certification, valid from January 2025 to January 2026.

Published

1 day ago

February 4, 2025

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Sambhv Steel Tubes Limited, one of the key manufacturers of electric resistance welded (“ERW”) steel pipes and structural tubes (hollow section) in India in terms of the installed capacity as of March 31, 2024 (Source: CRISIL Report) is pleased to announce that it has been officially certified as a “Great Place to Work® for 2025.

This certification, valid from January 2025 to January 2026, is a testament to the company’s commitment to fostering a workplace environment built on trust, collaboration, innovation, and employee well-being. Sambhv Steel Tubes also invites talented professionals who share its values of trust, collaboration, and innovation to join its team and be part of its growth journey. The Great Place to Work® certification is a recognized benchmark for workplace excellence. It is awarded based on employee feedback and an evaluation of workplace practices. Achieving this certification underscores Sambhv Steel Tubes’ dedication to nurturing a culture where Sambhv Steel strives to ensure that employees feel valued, supported, and empowered to grow both personally and professionally

The DRHP is available on the website of the Company at www.sambhv.com, SEBI at www.sebi.gov.in, websites of BSE Limited at www.bseindia.com and National Stock Exchange of India Limited at www.nseindia.com and the website of the book running lead managers, i.e. Nuvama Wealth Management Limited and Motilal Oswal Investment Advisors Limited at www.nuvama.com and www.motilaloswalgroup.com, respectively. Any potential investor should note that investment in equity shares involves a high degree of risk and for details relating to such risk, please see the section entitled “Risk Factors” of the RHP, when filed. Potential investors should not rely on the DRHP for making any investment decision. This announcement does not constitute an offer of the Equity Shares for sale in any jurisdiction, including the United States, and the Equity Shares may not be offered or sold in the United States absent registration under the US Securities Act of 1933 or an exemption from registration.

Any public offering of the Equity Shares to be made in the United States will be made by means of a prospectus that may be obtained from the Company and that will contain detailed information about the Company and management, as well as financial statements. However, the Equity Shares are not being offered or sold in the United States. CRISIL Market Intelligence & Analytics (CRISIL MI&A), a division of CRISIL Limited, provides independent research, consulting, risk solutions, and data & analytics to its clients. CRISIL MI&A operates independently of CRISIL’s other divisions and subsidiaries, including, CRISIL Ratings Limited.

Image Source: Sambhv Steel Tubes

Concrete

Cement Industry Key to Growth, Jobs, and Nation Building in Budget

Budget presents opportunities for cement sector in growth, jobs, and infra.

Published

1 day ago

February 4, 2025

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The Cement Manufacturers’ Association (CMA) welcomes the Union Budget 2025-26 presented by the Honourable Finance Minister Nirmala Sitharaman. CMA Member Companies have been at the forefront of nation building by significantly contributing to infrastructure development, employment generation, and economic growth. CMA believes that the Budget presents a commendable vision for India’s development through strategic investments in people, economy, and innovation.

Commenting on the Budget, Neeraj Akhoury, President, Cement Manufacturers’ Association (CMA) and Managing Director, Shree Cement Limited, stated, “CMA hails the Union Budget, announced under the leadership of Prime Minister Narendra Modi for its comprehensive focus on holistic and inclusive development. The Budget reinforces a transformative journey towards building a resilient economy for advancing India’s development goals. The various initiatives announced by the Government balance people’s aspirations with the future requirements for the Country’s economic growth. The focus on increased investments on infrastructure across States amplifies opportunities and avenues for the growth of the Cement sector. We appreciate the sustained core focus on infrastructure and reiterate our commitment to being partners in Nation’s progress.<p></p>

<p>The increased spending on large scale housing and infrastructure projects will drive demand for construction materials allowing capacity expansion and promotion of innovation in sustainable practices. We are certain that despite challenges these measures will support the Cement Industry in achieving a consistent CAGR growth rate of more than 6 per cent of installed cement capacity in the present financial year. Policy reforms in Budget 2025-26 signal a reaffirmation of the Government’s intent to augment socio economic growth across core sectors.”

The Cement Industry plays a vital role in creating direct and indirect employment across various sectors, including manufacturing, logistics, and construction, thereby supporting millions of livelihoods. Additionally, the industry remains a key contributor to the Government exchequer through taxes, duties, and levies, strengthening the country’s fiscal framework.

Parth Jindal, Vice President, Cement Manufacturers’ Association (CMA) and Managing Director, JSW Cement Limited, said, “The Budget presented by Finance Minister Smt. Nirmala Sitharaman is a forward-looking roadmap that will play a pivotal role in shaping the future of India’s cement industry, in line with the country’s vision for a Viksit Bharat by 2047. It prioritizes growth in key sectors such as infrastructure, manufacturing, and technology. The increased investment in technology will accelerate advancements in green cement solutions, driving both sustainability and innovation within the industry. Notable allocations, including Rs 200 billion to foster innovation and Rs 1.5 billion in 50-year interest-free loans to states for capital expenditure on infrastructure development, are expected to significantly bolster growth in the core sectors, including cement sector.

He further added, “The Budget’s focus on a three-year pipeline of projects under the public-private partnership (PPP) model will incentivize private sector investment and catalyse a transformation in the infrastructure landscape. Additionally, the establishment of five National Centers of Excellence for skill development, as part of the ‘Make for India, Make for the World’ initiative, will ensure that India’s emerging workforce is well-equipped to meet the demands of a rapidly growing economy.”

In light of the recent Budget announcements, which prioritise infrastructure expansion and affordable housing, the Cement Industry is poised to leverage these opportunities by ensuring steady and sustained supplies of Cement to meet the Nation’s growing domestic market and infrastructure demand coupled with sustainable and innovative technologies. With a strong commitment to sustainability and efficiency, the Cement Industry will continue to drive India’s progress and economic resilience.

Concrete

GMDC Inks Long-Term Limestone Supply Deal With JK Cement

The agreement has been signed for supply of 250 million tonne.

Published

2 days ago

February 3, 2025

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State-owned GMDC said it has entered into a long-term pact with JK Cement Ltd for the supply of limestone from its upcoming mine in Gujarat.

The agreement has been signed for supply of 250 million tonnes of limestone over a period of 40 years from its upcoming Lakhpat Punrajpur Mine in Lakhpat Taluka of Kutch district in Gujarat.

This agreement will help JK Cement Ltd in setting up an integrated mega-capacity cement plant, fostering industrial growth in the region.Kutch’s coastal proximity, improved access to domestic and international markets, and cost-efficient logistics position it as an ideal hub for cement production.

The state-owned company has five operational lignite mines in Kutch, South Gujarat, and Bhavnagar region.