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Choudhury S.,AFCONS Infrastructure Ltd
Indian Concrete Journal | Year: 2015

The 'crown' project for our company may probably be the Chenab bridge project which would be the world's highest rail bridge. The projected time of completion would be in 2016 and arguably one of the toughest engineering challenges in hand. This paper reports an experiment conducted on concrete in terms of workability, high strength and durability to fill the closed arch box segment of steel arch type of bridge over river Chenab. The Arch Segment is a closed rectangular steel box size 9.0 m x 1.0 m x 0.5 m with diaphragm wall in between and reinforcement cage inside. The box consists of single opening at top end for pouring concrete. The concrete mix is designed keeping in view the placement difficulties and access of concrete to every nook and corner of the 9-m length Arch Segment. Concrete infill in arch aimed to induce more weight to the structure to withstand high wind pressure in the area. The mix design specification being new, required approval of Indian Railways.

Nagar R.P.,AFCONS Infrastructure Ltd
Corrosion | Year: 2011

Selection of an electrically remote location of an anode groundbed with respect to its cathodic-protected pipeline and nearby foreign pipelines/ structures is an important element of the design of impressed current cathodic protection systems. Proper understanding of commonly available and used practices is essential for selecting electrically remote locations of impressed current anode groundbeds. To facilitate proper design and evaluation of anode groundbeds of impressed current cathodic protection systems for cross-country pipelines, this paper contains a comprehensive review of commonly used practices and presents an improved technique for the calculation of earth potentials for the determination of remoteness of impressed current anode groundbeds. © 2011, NACE International.

Gopalakrishnan R.,AFCONS Infrastructure Ltd
Indian Concrete Journal | Year: 2015

The LNG Marine Jetty Project consists of Approach Trestle, Unloading Platform, Berthing and Mooring Dolphin, Tug Berth, Northern Spur Bund and Causeway structure in off shore and on shore area. The causeway portion is located inbetween of sea shore and Tug berth Trestle and this area has soft clay with high water content up to depth 20 m from sea bed level. Due to loose soft clay, the average residual settlement is very high. In order to accelerate the primary settlement due to consolidation process as well as ground improvement, use of Prefabricated Vertical Drain simply called as PVD technique of ground improved was used to improve the strength of weak soil layer and to accelerate the consolidation process. This case study describes the settlement on causeway portion, PV Drain method technological and installation of PV Drain.

Narvekar S.G.,AFCONS Infrastructure Ltd
Indian Concrete Journal | Year: 2015

The necessity of high strength high performance concrete is increasing because of demands in the construction industry. Efforts for improving the characteristics of concrete over the past few years suggest that cement replacement materials along with chemical admixtures can improve the durability and corrosion characteristics of concrete. High Reactive Metakaolin (HRM) is a pozzolanic material that can be utilised to produce highly durable concrete composites. However, information to understand the behaviour of this mineral additive in concrete is insufficient. Some of the recent information is discussed in this paper highlighting the role of metakaolin in high strength high performance concrete. The concept of durability of concrete is contradictory to the misleading notion developed in the past that concrete is permanent and doesn't require any maintenance. Concrete subjected to repeated cycles of freezing and thawing may deteriorate rapidly, or it may remain in service far many years without showing signs of distress. Failure of the material be in the form of loss of strength, crumbling or a combination of the two. It is likely that due to varied behaviour of climatic conditions in cold weather regions, the fresh concrete or hardened concrete gets subjected to freezing and thawing cycles. The durability of concrete gets greatly impaired due to this alternate freezing and thawing. It exerts fatigue in concrete. Similarly, alternating cycles of wetting and drying during the curing process is also extremely harmful to the concrete surface and may result in surface crazing and cracking. Keeping in view the large coastal line of our country, the concrete used in coastal structures are also susceptible to distress due to several factors, some of which are common and they affect the durability of concrete in general. Concrete is an important versatile construction material, used in wide variety of situations. When we talk of a construction material, it is very important to consider its durability as it has indirect effect on economy, serviceability and maintenance.

Bamane N.N.,AFCONS Infrastructure Ltd
Indian Concrete Journal | Year: 2015

This paper is about construction of the single colossal open chamber, 240 m long, 80 m wide, 50 m high, partly below ground and partly above ground framing the Desilting Chamber arrangement for the Kol Dam Hydro Electric Power Project in Himachal Pradesh. It posed numerous challenges during construction as a consequence of (i) project uniqueness, (ii) the difficult ground conditions, (iii) the end uses / functional requirement of the chamber, (iv) interface work, (v) the physical layout arrangement of the chambers with respect to the multiple gate openings. This paper discusses the measures undertaken to safely excavate the chamber in the rock. The detailed construction steps taken to develop the staged sequences; like for the excavating of the full chamber profile are described and outline of the controlled excavation method is presented. In this paper the detailed construction method of the raft, weir, pier, combined pier, inclined pier, pier cap, gravity walls, cast in-situ deck slab and the erection of Trash Rack panels and the Trash Rack Cleaning Machine are explored in light of project execution planning of the desilting chamber during construction.

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