Tower of strength
The Executive Tower of Mexico’s Ministry of Economy has recently been extensively strengthened against seismic damage by the retrofitting of mageba RESTON®SA shock absorbers
The Mexican economy, currently growing at a respectable annual rate of 2.8% of GDP in spite of a certain amount of geopolitical uncertainty, is managed by the country’s Ministry of Economy from its Executive Tower in Mexico City. The 27-storey building dates from 1976, and was constructed to a seismic protection standard that is no longer sufficient. In order to strengthen the building, and ensure that it will continue to survive earthquakes such as those that destroyed a number of high-rise buildings in Mexico City in 1985, it was decided to install an array of RESTON®SA shock absorbers (viscous dampers), complete with steel bracing, in each face of the building. With a pair of dampers per face at each of 25 levels, each damper in a pair acting in a different direction, the total number of dampers required was 200. These were designed for loads of up to 800 kN and seismic displacements of +/- 50 mm. The manufacturing process involved a high degree of complexity, considering in particular the very low alpha-value of 0.1 (far more demanding to achieve than typical values of about 0.3). To provide complete confidence in the actual seismic performance of the dampers, full-scale, full-speed testing was carried out, simulating exactly what would happen in an earthquake. Great care and a high level of attention was paid to packaging and transport, and to handling at all stages, including during installation, to ensure that these high-precision devices would not be adversely affected in any way.
This was the second such retrofitting project in Mexico’s history, following the installation of seismic dampers in the existing Lerma Building in Mexico City. In that case, two years earlier, similarly dimensioned, fully tested mageba RESTON®SA shock absorbers (76 in total) were added, in a similar way, to the 12 office floors of the 17-storey building. This groundbreaking project in the Mexican context provided the local engineering sector, and especially mageba Mexico, with valuable experience and know-how in state-of-the-art seismic protection of high-rise buildings.
Retrofitting of the shock absorbers to the Ministry of Economy building is now being carried out. The work is expected to be completed during the summer of 2017, ensuring that the tower, like the robust economy it symbolizes, will be able to withstand any unexpected shocks for many years to come.