India's first integrated multi-model transport system, Reach-1 of Kochi Metro has been making waves since its recent completion. Phase-1 stretches from Aluva to Petta over 25.16 km with 22 stations. Of this, the currently commissioned and operational stretch is nearly 13.25 km, with 11 stations from Aluva to Palarivattom.
Overcoming the challenges
Kerala is known to be tough on big projects in terms of single-window clearances and timely approval. That said, for the Kochi Metro Rail (KMRL) project, 600 parcels of land were acquired. 'The main difficulty was delay in land acquisition during the execution of the first phase, for which 90 per cent of land acquisition has now been completed,' explains Elias George, Managing Director, KMRL.
'After the introduction of the New Land Acquisition Act in 2013, we faced difficulties that led to delays during that time.'
Other major challenges in execution included heavy monsoons, a quarry ban affecting aggregate supply, unforeseen underground utilities, and labour strikes in the state. Nevertheless, Kochi Metro was constructed within a record 45 months and is known to be the first metro to have completed a length of 13 km so rapidly.
The total construction cost for the 25.16 km Phase-1 is Rs 5,181.79 crore, of which Reach-1 has 11 stations, 51 escalators and 37 elevators, and 34 air-conditioners inside and outdoors. In the first reach, it has two types of stations: Type-I and Type-II. All stations are elevated, consisting of an on-road main station building and entry and exit buildings on either side of the road except for Aluva station. Owing to the constraints posed by narrow roads, non-availability of land and difficulty in land acquisition, the main station building has been designed as a cantilever structure. 'The construction methodology followed for the foundation and substructure for stations is similar to that of the viaduct,' shares Thiruman Archunan, Director (Projects), KMRL.'Over the piers, cast-in-situ station pier arms with 22.5-m width have been constructed over multiple levels, ie in the concourse and platform levels. Owing to space constraints in erecting a conventional formwork system, innovative technology of top-down construction has been adopted to cast the station pier arms. Over the pier arms, pre-tensioned station beams have been erected. The station length ranges from 80 m to 100 m. Over the platform level, the station roof truss has been erected and roof sheeting done.'
Kochi Metro has made use of the U-shaped girder for construction, pile rig and high grid, which was mainly used along with other general equipment. The superstructure of the viaduct consists of post-tensioned U-girders and pre-tensioned I-girders of a minimum radius of 432 m and 152 m, respectively. The span of U-girders ranges from 20 m to 25 m and the span of I-girders varies from 10.6 m to 35 m. The precast U and I-girders were transported to site from the casting yard using multi-axle heavy duty trailers and erected using two cranes with 350-tonne and 400-tonne capacity.
'For the positing of the 400-tonne crane, a width of 14 m was required,' adds Archunan. 'As such, girder erection works were mostly carried out at night after diverting the road traffic. To reduce the demolition of adjacent structures for positioning of cranes, several U-girder spans were changed to I-girders, thereby reducing the need for land acquisition and demolitions.
Over the I-girder spans, cast-in-situ deck slabs have been cast.' The foundation of the elevated viaduct consists of bored cast-in-situ piles ranging from 1 m to 1.5-m diameter and its depth varies from 15 m to 40 m, depending on geological conditions. 'The substructure works, predominantly the piers, have been designed in a circular shape of 1.6-m diameter,' elaborates Archunan. 'The height of the piers range from 6.5 m to 22 m; the tallest piers have been constructed in one of the busiest locations, Edapally Junction.
To reduce hindrances from land-related issues, the viaduct has been constructed substantially in the road median location. Over the piers, precast and cast-in-situ pier caps have been constructed; and based on the requirement, normal, cantilever, extended and transit pier caps of about 9.75-m width have been constructed.'
Going the solar route
To ensure that green energy is made available, solar panels have been fixed over the station roofs. The project currently plans 4 MW on the rooftop, of which 2.3 MW has already been installed.
KMRL is in the tendering process for an additional 2.2 MW on the ground level. 'Once the 6.2 MW is completed, KMRL can reduce the usage of 30 per cent from the total conventional energy consumption,' shares George. 'We will definitely implement the solar panel at Muttom yard as per availability of space.'
Modern signalling system
Notably, Kochi Metro is the first metro project to be commissioned with a modern signalling system.
As George explains, 'The communication-based train control system for the main line and depot is a moving block train control system that works on the principle of target speed and target distance with cab signalling, by continuously monitoring the position of each train and the state of all trackside elements, for example, points, emergency stop plungers or switches, by means of continuous transmission between trackside and train through radio control.'
This ensures safe movement of all trains under all operating conditions by continuously generating a safe operating envelope defined by the limit of movement authority and the maximum safe speed. 'The limit of movement authority will be the farthest point to which the train may safely proceed, taking into account margins for error in speed and distance measurement, calculating braking distances and the equipment reaction times,' adds George. 'The maximum safe speed will be the maximum speed at which the train is permitted to travel without intervention by the train control and signalling system, and it will continuously be calculated in a manner that permanent speed restrictions, the speed limits for the type of train and temporary speed restrictions will not be exceeded, and the train will always stop without passing the limit of movement authority.'
In a first-of-its-kind initiative in India, KMRL has commissioned a bank to implement an open loop smart card-based fare collection mechanism for the metro. The card and the app can become a pan-city solution for all payment needs. KMRL has also taken special care to make the project accessible for everyone. There is a special walking path for the visually challenged from the entry to the platform.
Each station has escalators and elevators for the elderly, pregnant and the differently-abled.
Further, Kochi Metro has been certified Platinum by IGBC for implementing eco-friendly practices for stations and to install solar panels at the stations and depot to reduce power consumption. It also has a vertical garden at every sixth pillar of the viaduct using municipal waste. ôWe are also in the process of providing WiFi connectivity to passengers, for which the tender procedure will begin soon,ö says George. In addition, KMRL has given attention to sensitising people about the importance of the Western Ghats and biodiversity with the use of themes and art at the stations.
KMRL has also started work on the remaining 12-km second reach of the first phase, which is expected to be completed by 2019. With this, there will be a considerable reduction in the number of vehicles on the road, and a decrease in air and noise pollution as well as road accidents. Expressing that the city will gradually get transformed into one with zero-carbon emission, George adds'The metro offers hassle-free travel and our larger objective is implementation of a seamless multi-modal integrated transport system in Kochi to make it congestion-free and eco-friendly.'
Moreover, water connectivity will be developed as a feeder service to the metro rail, for which the survey has commenced. In fact, a general consultant has already been appointed for this Rs 747-crore water metro project, which envisages the development of 16 identified routes, connecting 10 islands along a network of routes that spans 76 km. Remarkably, over 100,000 islanders are expected to benefit from the water metro, complete with modern watercrafts!
Total length: 13 km completed.
Date of operations: June 19, 2017.
Construction cost: Rs.5,181.79 crore.
Current ridership: 40,000 (as in September 2017).
Project consultant: DMRC. Tel: 011-2341 7910. Website: www.delhimetrorail.com
Phase-IA contracting agencies: For Reach-I (Aluva to Palarivattom): L&T. Website: www.larsentoubro.com; Soma. Website: www.soma.co.in; Era & Ranken (JV).
- SERAPHINA D'SOUZA
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