This is how we do it

Seismic isolation of a building complex.

Here we use pictures from a project in Mexico City – to supply large seismic isolator bearings for the construction of a new building complex – to illustrate some of the key steps that typically arise when mageba is supporting a construction project anywhere in the world

Espacio Condesa is a major development in Mexico City which, when it opens in 2021, will contain 572 apartments, over 50,000 m2 of office space and a shopping mall with over 25,000 m2 of floor space. To ensure the safety of the buildings and their users during an earthquake, it was decided to build the key structures on bearings which would isolate them from destructive seismic ground movements. After extensive dynamic analysis of the structural seismic response, and evaluation of various alternative bearing types, mageba recommended the use of seismic isolators of the lead rubber bearing (LRB) type to the building designer.

Having clarified all design requirements in close consultation with the client, our local design engineers settled on seven different bearing solutions to meet the development’s needs. Following detailed design of each solution by our seismic engineers and bearing designers, mageba supplied 203 enormous LASTO®LRB isolator bearings with an average diameter of approximately 1,200 mm (4 ft), each designed to support loads of roughly 20,000 kN and allow seismic displacements of up to +/– 300 mm. Due to the huge weight forces of up to 82,760 kN to be supported at many of the 87 bearing locations, it was necessary to combine a number of these isolators together to form 11 “double” and 35 “quadruple” bearings, with either two or four individual isolators connected by a single steel anchor plate above and below.

The bearings were manufactured in our Indian factory, along with four extra prototypes for testing. Full testing of the prototypes, and quality control testing of 41 installation bearings, was carried out in the presence of the project structural engineer at the SISMALAB seismic testing facility in Italy. Having confirmed the design and production quality of the bearings by means of this extensive testing, they were carefully packed in wooden crates and transported to site in dedicated shipping containers (19 in total) to avoid any risk of damage.

Following the bearings’ arrival on site in Mexico City, our supervisor discussed the installation process in detail with the main contractor’s personnel, and supervised the installation of the first six units while training the contractor’s staff to do the rest themselves. Of course, our team remains ready and willing to answer any questions or provide further assistance until the project has been completed, rounding out a project that began for us several years before and will be a source of pride for us for many years to come.

Building designer: GALLEGOS CONSULTORES
Contractor: NÉMESIS PROYECTOS SA DE CV
Owner: FIBRA PLUS

The Espacio Condesa development, with its 572 apartments as well as a shopping mall and over 50,000 m2 of office space, will tower above the local cityscape

Construction in the age of Covid – face masks required

Step 1. Support with selection and specification – Including evaluation of different possible solutions, such as curved surface slider bearings (cut-out view of a pre-design shown here), to establish approximate size and other consequences … before settling on the use of lead rubber bearings (LRBs)

Step 2. Design – With calculations in accordance with project specifications and applicable standards

Step 3. Design approval – As required, often with use of accurate and informative representations, such as this one of a “quadruple” LRB isolator bearing consisting of four individual LRB isolators connected by a single steel anchor plate above and below (Cut-out view showing the lead core of each LRB)

Step 4. Fabrication – two “double” LRB bearings as manufactured at mageba’s Kolkata factory

Step 5. Testing – of a “single” LRB at the SISMALAB seismic testing facility in Italy

Step 6. Packing – of a “double” LRB bearing in a wooden crate for excellent protection during transport to site in Mexico

Step 7. Transport – with the wooden crates securely fixed in a total of 19 shipping containers for further protection during the voyage to site

Step 8. Unpacking and installation planning – after delivery to site in Mexico City

Step 9. Installation – of a “single” LRB isolator bearing on a concrete column (installation of the first six units was supervised by mageba technicians, ensuring that the contractor’s staff had the required capabilities to install the rest on their own)

View of a section of the site following installation of a number of the bearings

Close-up view of a “quadruple” LRB isolator bearing, weighing 7020 kg, as installed

A “quadruple” lead rubber bearing following placing of part of the superstructure on top of it