Construction of Reinforced Earth® wall at Trumpet Interchange of Phase I on NH-07 at Bengaluru International Airport in the state of Karnataka, India.
Project Details
TYPE
RE Wall Type TerraClass® with HA Galvanized Steel Strips
OWNER
Bangalore International Airport Limited (BIAL)
CONTRACTOR
L & T Limited
CONSTRUCTION YEAR
2008
DESIGNER + CONSULTANT
- Terre Armée (Reinforced Earth India Pvt. Ltd.)
- Span Conaultants Pvt. Ltd.
Background
Bangalore International Airport (BIAL) is located in Devanahalli, 34 KM from CBD on NH-07. Due to the rapid growth of its IT sector, Bengaluru needed a world class airport for its customers, so the government of Karanataka planned to build new airport at Devanahalli.
It was necessary to build a Trumpet interchange to provide access for vehicles commuting from Bengaluru as well as Hyderabad to cross NH-07. Apart from major road like NH-07, an additional Road Over Bridge (ROB) and a Vehicular Underpass (VUP) needed to be built.
BIAL awarded the project to L&T Ltd. The Trumpet interchange had a major flyover merged with ROB, two ROBs and a VUP to provide signal free access for vehicles from both Bengaluru and Hyderabad, without affecting entry for adjacent villages.
Challenge
Designing the Reinforced Earth® wall needed many details with respect to overlapping of ramps, close proximity of ROBs and diagonal ramps.
At CH 1+120, a flyover on NH-07 needed to be merged with an ROB. At the same location, all 3 ROBs would converge and have a single ramp with a closing wall of 150m length. Also at the ROB location, the height of wall would be 15m.
Time was a major challenge, too, as L&T Ltd wanted to complete the entire project in five months. Terre Armée in India worked 24 x 7 to achieve the deadline. The project not only tested Terre Armée’s design and construction abilities, but also tested its supply chain with its massive requirement of materials in a short span of time.
Solution
In a detailed design process, Terre Armée in India used in-house technical know-how to design the Reinforced Earth® wall using High Adherence (HA™) Galvanized Steel Strips as soil reinforcing elements with well graded fill material having angle of internal friction (Ф) > 32º and considering normal traffic surcharge for the design as per IRC 6.
Terre Armée in India successfully designed the structure considering all the requirements of the client.
Terre Armée in India supplied enough moulds, keeping the tight construction period in mind, to produce precast panels well in advance.
The entire construction of the 39,300 sq m Reinforced Earth® wall was completed in the stipulated in five months without any cause for complaint or safety lapse.