17 meters high reinforced retaining wall for the construction of a new highway crossing the central mountains to link the cities between North Lebanon and the Bekka Valley

retaining wall for the construction of a new highway, Lebanon

PRODUCTS:

Modular block retaining wall
TENAX TT geogrids

Location - Date:

Central mountain, Lebanon - 2007

Designer:

Geoscience S.A.R.L., Lebanon

Consultant:

ACE

Contractor:

Srouji Est.

Problem
Construction of a new highway crossing the central mountains to link cities in the north to Bekaa valley in the east, required retaining walls ranging in height from 10.0 m to 17.0 m.

Reinforced concrete walls were ruled out due to the high cost and technical difficulties associated with the design and construction of high reinforced concrete walls.

construction of a retaining wall in Lebanon

retaining wall in Lebanon

Solution
Geoscience, a leading geotechnical firm and the local TENAX distributer, proposed a-cost effective mechanically stabilised earth retaining wall solution using TENAX geogrids as the reinforcing element and the Geoscience Modular block as a facing unit.

Wall designs were carried out as per AASHTO specification using the MSEW software.

Traffic and seismic loads were considered and the factors of safety obtained for the different modes of failure were in compliance with those specified by AASHTO.

The modular block wall system was constructed to heights ranging from 10 to 17 metres.

TENAX TT geogrids reinforcement layers were incorporated within the backfill at 40 and 60 cm spacings. Compaction was carried out in 30 cm lifts to ensure the required design load capacity was met.

The unique design of the Geoscience modular block allows for a free draining material to be placed in the hollow space inside the blocks to act as a drainage medium thus eliminating the need for placement of a drainage layer behind the wall.

Monitoring of the completed walls indicated very good performance with negligible settlement occurring.

Conclusion
The use of TENAX TT geogrids and GEOSCIENCE Modular Block retaining wall system allowed the consultant to minimise land take and incorporate an aesthetically pleasing finish.

Observations of the completed walls showed no signs of settlement or movement.

The geogrid reinforced block wall system provided the following benefits:

Quick and simple construction method allowing the project to be completed within the required time frame
A cost-effective solution that allowed the project to be constructed within budget
An aesthetically pleasing facing unit
A free draining reinforced soil structure

Applications:

Construction of retaining walls