When in mid-2020 Terraforce received the final images of a newly completed Terraforce earth retaining wall at the Salamanca Hospital, Salamanca, Spain, we were immediately struck by the technical excellence on display. Having followed the installation process step by step, this outstanding outcome is not surprising.
Skilled contractors are key to great Terraforce wall
Installed and designed (using the Terraforce Maxiwall Pro software) by ORBE Tecnicas Y Medioambiente, an environmental engineering company specialized in the construction of reinforced soil structures, the four Terraforce rock face finish retaining walls cover 2300 m² surface area, with a maximum height of 7,86 m.
Says Miguel Seller, Civil Engineer at ORBE Tecnicas Y Medioambiente: “The main retaining wall supports a new access road to the hospital, and in some sections special consideration had to be given to the placement of geogrids due to the presence of a large drainage pipe (2,5 m in diameter) near the visible face of the wall.
Facing challenges with confidence
“Another unique challenge was that we had to adapt the slope of the concrete block wall to meet another vertical wall, which was very complex from a topographical point of view. Another interesting technical aspect to highlight is that part of the Terraforce wall is set in a floodplain area of the river Tormes, so in those cases a permeable soil was used as the reinforced soil, with better geotechnical characteristics.”
Quality Geogrids for extra strength
Seller adds: “We used Huesker (Fortrac) geogrids with nominal tensions between 35 and 80 kN. The natural foundation ground was a slate soil, with 28º of internal friction, 10 kN / m2 of cohesion and 19.95 kN / m3 of specific weight. In the reinforced soil, we use a soil with 30º internal friction and a density of 20.00 kN / m3, of course without cohesion.”
The new road, Paseo de la Transición Española, adds a length of almost 600 meters to the existing road system and provides direct access to the hospital emergency zone. It also includes another central roundabout that allows access to the new hospital complex and future parking. Landscaping and a bicycle path are still to be completed.
Without a doubt the completed project is pleasing to the eye, and the additional coping blocks, the fencing along the top, as well as the large rock strip lining the base add an eye-catching visual dimension to the wall.
Client: Salamanca City Council
Project Manager: Excelentísimo Ayuntamiento de Salamanca
Main Contractor: Ferrovial Construcción
Sub Contractor: ORBE Tecnicas Y Medioambiente
Block Supplier: Prensagra Prefabricados