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Mullan Mor Housing

Walls up to 36 feet high constructed in difficult ground conditions and subject to specific requirements from the planners

Key Features

Wall Area

​26,900 sq. ft.; 36 feet high

Location

​Glenanail, Galway, Ireland

Manufacturer

​Acheson & Glover Ltd.,
Co. Tyrone, N. Ireland

Wall Design Engineer

Maccaferri Ltd.
Belfast, N. Ireland

Wall Contractor

Michael Fitzgerald & Sons
Galway, Ireland

Mullan Mor Housing
Mullan Mor Housing

The Challenge

​A brownfield site, previously used as a landfill on the outskirts of Galway, was to be redeveloped for housing. A system was required that would be rapid and simple to build, as the excavations would be within unstable waste material. To avoid leaving the unprotected landfill exposed for too long, the contractor also required a system that could be built in short lengths.

An additional requirement was that the system had to be chemically inert to the waste within the landfill, and be capable of retaining the site access road along one side of the development, 36 feet vertically above the toe of the landfill.

The Solution

​The Landmark retaining wall system offered several unique benefits for this project. Construction is rapid with the modular dry-stack system. The geosynthetic reinforcement used within the structural backfill was specifically chosen to be unaffected by the landfill material and leachates.

A unique lock bar anchors the geogrid into the Landmark block, forming a connection between fascia blocks and the geogrids reinforcing the structural backfill. 

At their tallest, these walls needed to be 36 feet tall. Local planners also required that in some areas the walls be split into three 12-feet high terraced walls to accommodate a requirement for steps down to a park area and to soften the aesthetics of the structure facing the road.

The planners extended this requirement for a soft appearance by not allowing any 90-degree corners to be built within the wall. The Landmark system is ideally suited to this requirement.

Although the contractor had no previous experience with similar systems, on-site training enabled them to use their own labor to build the wall quickly and cost-effectively.

A key benefit identified by the contractor was that the Landmark retaining wall system could support heavy construction equipment immediately, without the need to wait for the concrete to cure as with traditional cast-in-place walls.

The Results

​In selecting the Landmark retaining wall system, the developer maximized the land available for housing and also overcame the significant technical difficulties on the site. Because the wall could be built in sections, the contractor was able to be flexible in phasing the construction, in line with the overall development program. The use of on-site labor further enhanced the cost-effectiveness of the whole project.

The split face and the earthen colors of the Landmark blocks used on this project contributed to an aesthetically pleasing scheme that met the demanding requirements of the local planners.

HITEC-Evaluated
For high performance under extreme loading conditions, the Landmark retaining wall system is a cost-effective option evaluated by HITEC. The Landmark system features a unique mechanical connection, which allows the system to generate extremely high connection values, independent of blocks above the connection. Developed specifically to meet the high standards of the transportation industry, the performance features of the Landmark system make cost-effective design solutions possible using either the American Association of State Highway and Transportation Officials (AASHTO) or the National Concrete Masonry Association (NCMA) design methodology.

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