CRB Walls for Cemetery Expansion Project in Madrid

The South African Concrete Manufactures Association (CMA) member, Terraforce, has scored another notable offshore retaining wall success. Its Terraforce L12 rock-face Concrete Retaining Blocks (CRBs) have been used for the construction of segmental retaining walls at La Almudena Cemetery in Madrid, Spain.

Built in 1884, the 120 acre cemetery is Europe’s largest and a popular tourist attraction. With close on five million graves, its monuments display various architectural styles: Neoclassical, Neo-romantic or Neo-mudejar and typical Madrilenian.

Required to create horizontal platforms and terraced gardens from a plot previously filled with waste material, the retaining walls were designed by ORBE Técnicas Medioambiente and Prensagra Prefabricados manufactured the Terraforce CRBs.

“Initially the plan had involved the construction of in-situ concrete walls,” said ORBE civil engineer, Miguel Seller. “However, the presence of extremely soft soils up to great depths led the project team to seek alternatives.

“Geotechnical testing helped us arrive at optimal wall designs and we recommended the installation of green reinforced soil walls (Green Walls) in certain areas and segmental walls in others. In the past we have built 10m walls using Terraforce blocks. We analysed internal wall stability using Terraforce‘s Maxiwall Pro software, and we compared the results with our own software analysis and a global stability assessment. Based on this research, we proposed reinforcing the foundation beneath the segmented wall with geogrids and improved soil.”

10,500 Terraforce blocks

All told 10,500 Terraforce L12 blocks were installed, resulting in visually striking rock-face walls. Reinforced with geogrids at every second row and stepped outwards at intervals with precise ninety-degree corners, the walls also accommodate gently sloping access ramps, stairs and rectangular garden features. To finish off the overall linear look, straight-lined steel rails were inserted into top row of CRBs which had been filled with concrete for that purpose.

Text: David Beer