Slope Protection for Abutment of Bridge at NH-91

Slope Protection for abutment of bridge at NH-91

Location NH-91, Aligarh - Ghaziabad, Uttar Pradesh
Principal Client National Highway Authority of India (NHAI)
Client Name Galfar Engineering & Contracting India Pvt. Ltd.
Independent Engineer SNC Lavalin Engineering (I) Pvt. Ltd.
Application Slope protection with StrataWeb® geocells infilled with soil
System Used StrataWeb® Geocells
Project Completion February, 2015

Background

Galfar Engineering & Contracting India Pvt. Ltd. (GALFAR) was constructing the extension of the Aligarh - Ghaziabad Section of the National Highway NH-91 in Uttar Pradesh. The extension converts the existing two-lane carriageway into a modern four-lane highway. The side slopes of the highway embankments required protection against erosion from rain water runoff flowing down the slopes. Since the right of way was restricted, the slopes were steep as much as 1.5H : 1V with a maximum height of 12m.

Conventional Method of Slope Protection

Stone pitching is the conventional erosion control for bridge abutments. Stone may not be easily procured in many areas and there can be quarry restrictions. Besides, placing stone pitching requires skilled masons and even wet pitching may require regular maintenance. With deformation of the earth embankment, the joints of the pitching may open up and soil may pipe through.

Stone was not available near this site and was required to be brought from quarries with long leads and transport costs were prohibitive. Also considering that the slopes were as steep as 1.5H:1V, it would not have been feasible to have stable pitching.

Innovative Solution

Slope protection with StrataWeb® geocells infilled with vegetated soil was a more practical and long-term solution under the circumstances.

Geocells are an effective way to protect the soil along a slope from erosion by providing a stable layer of confined material over the surface. StrataWeb® geocells of 75mm depth with local soil infill was proposed to support vegetation growth and provide a green finish so that the infill does not get washed away.

Value Addition to the Customer

  • More stable option on a steep slope as compared to stone pitching
  • Rapid construction
  • Environmental friendly and green solution as compared to stone pitching
  • Cost effective