by Terri Wagner
Toronto-based developer Reichmann International wanted to build a premiere landmark structure in Mexico City's financial district. Toronto-based architectural firm, Zeidler Grinnell Partnership, along with Adamson Associates, responded with designs for a 225-meter, 57-story office tower in the seismically active area.
The building itself is made of steel, concrete and glass showcasing a rectangular tower with a curved façade on the historic Paseo de la Reforma avenue built by the Emperor Maximilian in the 19th century and a rooftop helicopter landing pad. The complex includes a 13-story parking garage (four levels underground) and 77,000 square meters of column-free office space with a total of 900,000 square meters of office space and 35,000 square meters of retail space. The US$250-million project has a plug-in bus duct riser system for its electrical needs, a triple-filtering air system and an internal water re-cycling system.
Schindler won the contract to provide vertical transportation equipment for the Torre Mayor with 20 of the units in a central core location. Katz Drago & Co. Inc. was the elevator consultant. Schindler provided a total of 27 elevators and two escalators:
-- five low-rise 26-passenger units at 1800-kilogram-capacity with a speed of 4mps, a rise of 77 meters, an FM500C drive and VX-GC control;
-- eight mid-rise 26-passenger units at 1800-kilogram-capacity with a speed of 5mps, a rise of 141 meters, an FM500C drive and VX-GC control;
-- seven high-rise 26-passenger units at 1800-kilogram-capacity with a speed of 6mps, a rise of 208 meters, an FM500C drive and VX-GC control;
-- one helicopter-pad, 11-passenger unit at 800-kilogram-capacity with a speed of 0.63mps, a rise of 20 meters, a W140 drive and a TX-GC control;
-- one freight unit at 2700-kilogram- capacity with a speed of 4mps, a rise of 223 meters, an FM620A drive and a TX-GC control;
-- one 26-passenger unit at 2000-kilogram-capacity with a speed of 0.63mps, a rise of 10 meters, an HYD drive and a SX control;
-- four parking garage, 21-passenger units at 1600-kilogram-capacity with a speed of 1.75mps, a rise of 25 meters, a PG 420 drive and TX-GC control;
-- two hydraulic units;
-- two escalators.
The following Schindler personnel assisted on the project: Schindler Mexico Project Leaders Kok K. Foo and Octavio Ortiz, Chief Engineer Ricardo Navarro and Head of Installation Ernet Dähler; Schindler Switzerland Overall Project Leader at the Top Range Center (TRC) Patrick Graça and TRC project participants Armando Lanfranchi, Juan Horacio Couceiro, Claudia Zöllig, Jürgen Truöl, Erich Linnemann, Stefan Häfliger and Marion Grünenfelder.
In addition, Schindler provided the Torre Mayor with its E-Vision system in all the building's elevator units. The system is based on a video encoder able to receive any audio/video signal and compress it using a Microsoft Windows/ Media 8 codec. The video server, also Microsoft Windows/Media, receives the compressed signal and passes it onto the car PC. The system can handle such video sources as DVD, VHS, VCD, TV or a video camera.
Overcoming the seismic activity challenge (the Torre Mayor lies in a Seismic Zone II) utilized the efforts of New York-based Mueser Rutledge Consulting Engineers (MRCE), the Cantor Seinuk Group, Mexico City's Enrique Martinez Romero S.A., a Mexico City-based geotechnical firm TGC Geotecnia and the engineering institute of Mexico National University. The combined group studied more than 25 structural systems before coming up with a conventional lateral-force-resisting system with an innovative supplementary damping system. U.S. Patent No. 6,397,528 B1 was issued due to the damper-and-diamond configuration. Mexican codes emphasize occupant safety over building safety. In other words, the building can be severely damaged, but the occupants must be protected. Torre Mayor's 98 dampers came in at a cost of about US$4 million. The basement extends 15 meters below the ground. The foundation utilizes 1.2-meter caissons that extend more than 50 meters to the rock-based region below the clay-like soil. A concrete mat reinforces the caisson with a thickness between 1-2.5 meters. The structure forms a tube system with the core columns encased in reinforced concrete up to the 35th floor. Seventy-four of the dampers are located in a north-south direction in the core while the remaining 24 are in an east-west direction in the four perimeter walls. Will this unique system work? It would appear so. On January 21, 2003, Mexico City was shaken by a 7.6 magnitude earthquake, centered in Colima, 498 kilometers to the east. Although the Torre Mayor was not yet complete, the 200 building occupants hardly noticed the trembler.