ON THE JOB

Preserving the Prado

How do you add an underground expansion to a building without causing major damage to the existing structure? This is one of the major challenges contractors have faced while building a 172,000-square-foot expansion at the Prado Museum in Madrid, Spain. The expansion will provide additional space for the museum to exhibit its collection of more than 8,600 paintings.

Designed by Spanish architect Jose Rafael Moneo, much of the new area is underground and on two levels. The new space will reach from the existing Prado to the 16th-century Jeronimo Church, the building adjacent to the museum. A tunnel will connect the existing building and the new.

The excavation for the new exhibition space measured 150 feet long by 66 feet wide by 66 feet deep. Because the size of this area would cause the foundations of the surrounding buildings and roads to become unstable, its walls needed to be supported and ground movement needed to be controlled.

An Enerpac PLC-controlled synchronous pushing hydraulic system will monitor and adjust any foundation movement between the church, the Prado Museum basement and the surrounding buildings during construction. Enerpac worked with the Spanish construction company ACS to develop this system.

On each level, 17 hydraulic jacks are positioned horizontally between the supporting walls and the concrete floors. The concrete floors are not yet fixed into the surrounding basement walls, allowing them to “float.” This is needed to accommodate and measure any foundation movement during construction. All 34 jacks push and keep the walls in position so the new exhibit area can be built without danger of the basement walls collapsing.