Tensar Geogrids Form Embankments In Ireland

Environmentally sensitive steep embankments for N8 road ccheme in County Cork, Ireland were constructed cost-effectively and reinforced with Tensar RE uniaxial geogrid.

As part of the Irish Government's National Development Plan, Cork County Council and the National Roads Authority upgraded the Glanmire to Watergrasshill section of the N8 in Co.

Cork, Ireland to a dual carriageway.

A section of the new road at the southern end of the scheme is above a valley with a stream running along the bottom.

To avoid encroaching on the stream, steep reinforced soil slopes were required for the new 20 metre high grass-covered embankment.

The slopes were constructed cost-effectively and reinforced with Tensar RE uniaxial geogrid.

Due to the presence of the stream at the toe of the slope, the embankments for the widened road and a bridge had to be constructed with face angles between 45deg and 55deg.

The JV contractor Mowlem/Bowen used Tensar RE uniaxial geogrid layered at 500mm vertical spacing to reinforce the locally won.

The soil face was contained by using a wraparound technique with each layer of geogrid wrapped up the face and then fastened to the next layer with Tensar's unique bodkin connection.

This enables a stable, consistent face to be constructed very rapidly over the whole slope.

In this case, instead of using a formal shutter, a large steel plate mounted on an excavator was used to temporarily support the wraparound face.

The embankment was designed in accordance with the DoT advice note HA68/94.

The geogrid face was lined with Tensar CE111, a fine mesh that is able to retain the topsoil layer, while allowing a hydraseeded mix to penetrate it, producing consistent grass cover to blend with the surrounding countryside.

The completed scheme opened to traffic in September 2003.

Client: Cork County Council/National Roads Authority.

Engineer: Atkins Ireland.

Contractor: Mowlem/Bowen JV.

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