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Bus Route Roads

Chennai - the Capital City of Tamil Nadu being the largest city in South India and one of the four Metropolitan Cities in the Country is the hub of major administrative, industrial, business , commercial , Information Technology, educational and socio-cultural activities, resulting in rapid growth.

Maintenance of City Roads is one of the challenging and Important function of Corporation of Chennai. In the last few years, various steps were taken for the up gradation of roads in the City. Interactions were held with premier technical institutions in Chennai like I I T , Anna University and Highways Research Station to provide world class infrastructure facilities

STATUTORY PROVISION

Section 204 of the Chennai City Muncipal Corporation Act 1919 entails the Corporation of Chennai to maintain public streets, repair and make all improvements there to which are necessary or expedient for the public safety and convenience.

BUS ROUTE ROADS

In Chennai City 304 Roads to a length of 222 Kms are Bus Route Roads. Bus Route Roads Department of the Corporation of Chennai maintains and improves all the Bus Route Roads periodically. The Bus Route Roads are being re-laid once in 5 years using paver finishers. The relaying of Bus Route Roads consists of laying Compacted Bituminous Concrete(CBC) 40mm thick wherever the existing base is badly damaged the road is strengthened by laying base course with DENSE Bituminous Macadam ( DBM ) 50mm thick. The unit cost of laying the Bus Route Roads as mentioned above is Rs. 409/- per Sqm as per current schedule of rates. (2005-2006 )The hot mix required for the relaying work are prepared by the contractors in their centralized Asphalt plant located in the outskirts of the City and brought to the site by tipper lorries, and laid at the site using mechanical paver finisher and rolled with vibrator rollers and static rollers. The temperature of the mix at all stages are strictly adhered as per the MORTH Specifications This makes it possible to achieve uniform and smooth riding surface. The process of laying roads in this manner is also very fast and causes less hindrance to traffic. Inorder to avoid traffic disturbances, Bus Route Roads are normally laid during the night and is opened to traffic in the next morning. The entire process of relaying Bus Route Roads is being carried out in accordance with the specifications of Ministry Of Road Transport and Highways ( MORTH ).

Mastic Asphalt

Mastic Asphalt Concrete is being laid as a wearing course for a thickness of 25mm at all important junctions and signal points of the Bus Route Roads. Mastic Asphalt concrete is capable of withstanding the force generated when brakes are applied by heavy vehicles and the force generated due to initial wheel momentum. In order to avoid damages to the road surface due to the application of brakes, this special technique is being used.

Patches And Potholes

Apart from periodical relaying of City Roads, the patches and potholes arising out of the road cuts made by the Service Departments and due to inundation of rain water during rainy season are being attended immediately by using Hot Mix prepared Departmentally in corporation owned Central Asphalt Plant located at Chetpet. Hot Mix is being produced everyday and sent to various divisions throughout the City for attending day to day patches and potholes.

Road Cuts

For Making any Road Cuts in Bus Route Roads or Interior Roads, the Service Departments have to get permission from Corporation of Chennai after remitting the necessary Road Cut Restoration Charges. Though utmost care has been taken for relaying of the city roads, the main problems faced by the Corporation of Chennai is the frequent road cuts made by several service departments such as CMWSSB, TNEB, BSNL, Private Communication Providers, etc. Though such road cuts are restored immediately, it does not uniformly match with the existing road surface. Such problems are inevitable in Major cities like Chennai.

Cement Concrete Roads

The total length of Cement Concrete Roads available in Chennai is 232 kms .Though the initial cost of the cement concrete roads is found to be high it is totally free from maintenance and have a larger life span of 20 to 25 years.

Laying of Cement Concrete Roads consists of 2 Types :-

1.The Roads where the width is less than 2.8m and the road construction machinery cannot move into the narrow street and where the movement of traffic is less, in such roads the normal design adopted is a base course of plain cement concrete of 100 mm thick in the ratio of 1:4:8. The top layer is of plain Cement Concrete of 150 mm thick in the ratio of 1:2:4.

2.The Roads where there is heavy vehicular movements and are frequently damaged due to perennial water stagnation and also roads located around Metro Water Filling Stations, in such roads the following specifications are followed in accordance with design based on Soil conditions, traffic study and adopting MORTH specifications.

• Granular base Course :- Sand Gravel Mix of 150mm to 250mm thick
• Sub-Base course :- Dry lean Concrete of 150mm thick using M10 Mix.
• Wearing Course :- Pavement Quality Concrete 250 to 300mm thick using M40 Mix
  
  

Footpaths

As another part of giving face lift to the roads, footpaths are constructed with Cement Concrete kerbs of IRC size 450x375x200mm and interlocking Cement Concrete pavers of size 125x50mm.

Traffic Centre Medians

Traffic Centre Medians are constructed in Bus Route Roads to ensure smooth flow of traffic. The Traffic Centre Medians are constructed with Random Rubble Masonry of 0.90 metre height and 0.60 to 0.90 metre wide depending upon the available width of the road. The space between the walls of the medians are provided with Greenery to improve the environment.