Construction of the largest reinforced soil wall using StrataGrid™ and StrataBlock™
|Location||National Highway 8 (The new NH48) – Ahmedabad-Vadodara stretch|
|Project||Expanding the highway from four to six lanes|
|Principal Client||National Highways Authority of India|
|Client Name||Modern Road Makers Pvt. Ltd.|
|Concessionaire||IRB Ahmedabad Vadodara Super Express Tollway Pvt. Ltd.|
|Independent Engineer||Aarvee Associates, Architects Engineers & Consultants Pvt. Ltd.|
|Project Size||294,900 sq.m. fascia area ; 46 structures|
|System Offered||Supply, design and construction of reinforced soil walls using StrataGrid™ as soil reinforcement and StrataBlock™ as fascia|
|Design methodology||BS 8006-1:2010(static) and FHWA-NHI-00-043(seismic)|
The National Highway NH-8 (The new NH-48) extends from Mumbai to Delhi. Along the route it also connects two major cities of Gujarat, Vadodara and Ahmedabad. The National Highway Authority of India (NHAI) required that the 102.30 km stretch between Vadodara and Ahmedabad be converted from four lanes to six lanes as part of its expansion programme for NH-48. The expansion project was awarded to IRB Infrastructure Ltd., one of the largest highway developers in India in line with the BOT (Build–operate–transfer) model.
The Project included 46 crossovers where the highway traverses over internal roads of towns and villages as well as three railway crossings.
The Conventional Method for Crossovers
The conventional solution to support approach ramps for the crossovers would have been reinforced concrete retaining walls designed as cantilever walls or walls with counterforts. Costs of such walls for each structure would have been colossal and with 46 such structures, the project costs would have shot up with a strong impact on project economics.
Strata’s Innovative Solution
In contrast, Strata advocated reinforced soil structures since they are faster to construct and cost-effective. The basic principle is to construct two parallel reinforced soil structures retaining earth backfill in between. The reinforced soil walls were constructed with locally available non-plastic soils and StrataGrid™ polyester knitted geogrids as soil reinforcement. The fascia comprised of StrataBlock™ precast segmental concrete blocks. The StrataBlock™ with StrataGrid™ system is extremely cost-effective.
TYPICAL CROSS-SECTION DRAWING
Strata's Value Addition
- Scale - Strata is the only company that could provide the turn-key solution required to construct 46 structures for a project.
- Cost-effectiveness - Saved up to 40% of the cost compared to conventional RCC walls.
- Turn-key – Strata was present throughout the project life-cycle: Manufacturing StrataGrid™ at its state-of the art plant, providing detailed designs by its highly qualified geotechnical engineers, and finally constructing the walls using on-site casting machines.
- Logistics – Built an innovative software to optimize the transportation from casting yards.