TECHABUTMENT® AND REINFORCED EARTH® WALL AT BASTORA JUNCTION ON NH 17, GOA

Assmas Construction Pvt. Ltd.

01/2017 to 04/2018

• Terre Armée (Reinforced Earth India Pvt. Ltd.)
• RITES Ltd.

Goa is a popular tourist destination in India, experiencing ever increasing traffic volume. The National Highway 17 (NH 17) provides major connectivity to Goa with neighbouring states. Goa has approximately 101 km of NH 17, running parallel to its coastline. Bastora junction is one of the major focal points, which experiences huge traffic congestion due to North-South connectivity. Due to the huge traffic demand, Public Works Department (PWD) Goa is constructing a bi-directional Vehicular Underpass (VUP) at Bastora junction to ease the traffic. A VUP of  20 x 5.5m clear span is proposed with  23m carriage way width.

Considering the project location and increase in the traffic density, completion time-line was the essence for this project. Safety of commuters during construction period was a major concern and challenge, as the terrain of Goa offers very limited space to provide traffic bypass or any type of diversion. The ground investigation revealed that the foundation soil strata was very poor up to 13m depth. Construction of wall and the true abutment on such poor strata was also another challenge and differential settlement was expected. Differential settlement on the abutment shall result in cracks on the bridge girder and slab.

After understanding the needs of the client and the project, Terre Armée India proposed a unique solution of TechAbutment® system along with Reinforced Earth® Wall solution to create an integrated innovative engineering solution to help client realise their project without any technical compromises,  with economic gain and time advantage.

Since, the geotechnical property of the foundation soil was not good, Terre Armée India proposed ground improvement and it was accepted by the client and the contractor.

TechAbutment® system is a true abutment where RCC Griders or Deck slabs are directly rested on Reinforced Earth® Walls. The uniqueness of this solution is that the conventional RCC abutments can be completely replaced with discrete panels, which provides better aesthetics also. TechAbutment® system was proposed at closing wall and return wall up to the length where the wall is subject to the bridge load. Considering the high loads, inextensible soil reinforcements were adopted. Terre Armée India adopted High Adherence Galvanized Steel Strips® to construct safe and sustainable true abutment solution.

For the approach ramp, Terre Armée India proposed to adopt GeoMega® system where GeoStrap5 soil reinforcing strips were used. Terre Armée India was responsible for design, sourcing of specialized materials and technical assistance at site for pre-casting and installation activities. The project was completed successfully within a span of 13 months.