By Maccaferri – For a 33m-high, 300m-long retaining wall along the new Tehran North Highway, a composite geosynthetic solution from Maccaferri is being utilized. This geosynthetic approach has enabled the project team to avoid construction of a bridge or a traditional concrete wall, and in doing so has made the works more cost-effective while simplifying the installation.
The ongoing construction works, which will connect Tehran to the Northern province of Mazandaran, are scheduled to be completed in October 2017.
20 YEARS OF DIFFICULT TERRAIN
The Ministry of Roads and Urban Development is overseeing the work, which actually began 20 years ago. The ambitious infrastructure endeavor will involved 121 km of roadway, divided into four primary sections, by the time it wraps up.
Section 1 is 32 km long. It starts from the cross section of Azadegan and Hemmat highways, continues passing through Kan, Soleqan, Emamzade Aqil, Taloon tunnel (which at 4,850m long is the most important structure of the section) and the Laniz Valley, after which it reaches the Shahrestanak junction. Once completed, the current path passing through Karaj will be omitted and the route to the Northern provinces will be shortened by 60 km. The completion of this section is of high priority and is set for the second half of 2017.
Works on Sections 2 and 3 will start when Section 1 will be completed. These are not easily accessible due to the several twists and turns in the unfriendly mountain terrain. Section 2 connects Shahrestanak and Zangoole bridge. This is approximately 25 km long and will include the Alborz tunnels, each 6,350m long. Section 3 connects Pol-e Zanguleh in the Kelardasht District, to Marzanabad with an approximate length of 46 km.
A GEOSYNTHETIC SOLUTION
Due to the topographical and geotechnical specifications of the region, and to the dimensions of the wall, which is up to 33m high and more than 300m long, a bridge or a concrete wall solution were found to be too costly.
Maccaferri’s design engineers, working closely with its distribution partner and site contractor, Rahyab Sanat Alborz, proposed a ParaMesh structure, which is a composite soil reinforcement system that uses both Terramesh and ParaLink products.
The Terramesh System is a double-twisted hexagonal steel wire mesh unit which forms the facia, with the aesthetics of gabion and with the cost-effectiveness of soil reinforcement.
ParaLink is a high-strength polyester geogrid used as the primary soil reinforcement.
The installation started in November 2016 and will be completed in October 2017. Once completed, the Terramesh System facing area will cover 7,500m² and 90,000m² of ParaLink 300 will have been used.
Learn more about Maccaferri’s geosynthetics and engineering services at www.maccaferri.com.1