Weirs, Culverts and Transverse Structures
HYDERABAD – VIJAYAWADA - ANDHRA PRADESH - India
National Highways Authority of India
REHABILITATION & WIDENING OF NH-09 HYDERABAD TO VIJAYAWADA SECTION
REHABILITATION & WIDENING OF NH-09 HYDERABAD TO VIJAYAWADA SECTION_0
REHABILITATION & WIDENING OF NH-09 HYDERABAD TO VIJAYAWADA SECTION_1
Photo 4: Foundation placing for gabion wall
Photo 5: Completed gabion structure
Photo 6: Completed gabion structure
National Highway 09 (NH-09) is one of the major national highway in India, spanning through the states of Maharashtra, Karnataka and Andhra Pradesh. The stretch from Vijayawada to Hyderabad was in a bad condition, NHAI had plans for widening on lake side for 96km and there was a need of retention for about 800m. The natural lake used to receive heavy rains due to which it would be full of water during monsoons and dry in summers. Gabions were found suitable for such conditions and a cheaper option as well. The project was sanctioned under the National Highway Development Program, Phase III. Due to the presence of ground water table at very shallow depth, it was a challenge to retain the slope filling. In addition to this, presence of water on one side and restriction of way on the other side restricted excavation, dewatering and erection of any form of work.
Gabion retaining walls were provided as the solution for the problem mentioned. The maximum height of retention for road embankment was 5m. Due to the presence of ground water table, it was suggested to create a base of rubble soling of 0.5m thickness with layers of gabion above it. Non-woven geotextile was provided as the filter media. Maccaferri gabion baskets are made from high quality steel wire, which is heavily galvanised to provide long term corrosion protection. An additional protective polymeric coating is also applied for gabions that are to be used in more aggressive environments, or where a longer design life is required. Key Reasons for selecting the Maccaferri solution were : 1) Flexibility- Accommodates ground settlement without any compromise in structural integrity. 2) Permeability and durability- Gabion wall allows free drainage which becomes an added advantage as the structure is adjacent to ground water table. 3) Simplicity in construction- The construction of gabion wall does not involve deep excavation, dewatering of trenches, erection of formwork. 4) Cost-effectiveness- Maccaferri’s gabion solutions are economical than rubble wall and R.C.C. wall.