Howth, Co. Dublin

Soil Nailing

Ireland

Scope of Works Remove collapsed material. Stabilise embankment. Reinstate embankment. Rebuild stone wall. Stabilise and repoint remaining wall.

INTRODUCTION

When a large masonry retaining

wall collapsed, the services of

McDonnell Piling were sought to

come up with a solution to

stabilise and reinstate the wall.

Traditional solutions would have

been to soil nail the slope,

construct a reinforced concrete

retaining wall, face it with stone

and backfill behind. McDonnell

Piling approached the site with

great concern for the area of the

site and the historical importance

of the wall.

We carefully removed any areas

of wall that were deemed unsafe

and all loose material on the

slope, installed the soil nails and

secured the slope with galvanised

mesh.

Reinforced Earths TerraNail

system was used to rebuild the

embankment out to its original

position, this was a key design

element as it meant that no load

from the embankment would be

imposed on the masonry wall

when completed. A free draining

stone was backfilled to ensure no

build up of water behind the wall,

new weep holes were

constructed into the new wall.

Embankment stabilised and reinstated with wall being re-built.

A5

Soil nailing using Reinforced Earth to reinstate the collapsed material.

CLIENT: Private

MAIN CONTRACTOR: McDonnell Piling & Foundations Ltd.

CONSULTING ENGINEER: Donal G. Terry & Associates

DURATION OF WORKS: Two months

www.mcdonnellpiling.ie

A5

A view of the collapse.

Soil nail installation

Slope base prepared for replacement

wall foundation.

Replacement wall construction, drainage

positioned behind the wall with weep

holes created at lower level. The stone

work was carried out using traditional

methods and materials similar to those

used approximately two hundred years

when the wall was originally constructed.

The wall itself is 600mm wide and

needed to be constructed in rises of no

more than 900mm in order to allow the

lime mortar sufficient time to achieve the

required strength. The drainage was

taken up in layers to ensure water could

be managed from behind the wall.

Soil nails extended into new wall to

provide additional tie for the wall.

Strapping visible for the TerraNail system.

Completed TerraNail system.

Completed wall.

www.mcdonnellpiling.ie