Recent work by Valarias DRV in downtown Mexico City
By Víctor Hugo Roldán Gonzáles
Built in 1527, the Antiguo Palacio del Ayuntamiento, (Town Council Palace) —one of the first ayuntamientos in America—was the first building in Mexico City, and is also the place where many important historic events of this country have occurred. This magnificent colonial construction is located at the south border of Constitution Plaza downtown Mexico City, also called Centro Histórico (Historic Center).
The original building was a two-story structure and for many years hosted the Salón de Cabildos (Corporation Town Hall), where the city was ruled. The third and fourth floors were added at the beginning of the 20th-century, and in 1929 the building was instituted as offices of the Federal District. Today, and due to the building’s historic importance to the citizens, the Antiguo Palacio del Ayuntamiento hosts Mexico City’s main offices of government, with a later version (beginning in the 1900s) of the Salón de Cabildos inside where the city government hosts events for distinguished visitors.
Due to the increasing use of the building’s two interior courtyard/patios for many politic events, and for the governor’s Monday morning press conferences—and more to the point, after some chaotic events in the rainy season using an ineffective mobile shelter—it became high-priority to cover both of the patios with a well designed, low-impact structure. It also became a main goal of the government to maintain the perception of the patios as exterior spaces.
Membrane structures are the best option to cover courtyards in historic buildings due to their low impact, especially where the massive weight of the ceilings and walls of the building serves as anchorage for the canopies. Our experience in making the cover for Palacio de Minería (Mining Palace, 2006) informed our decision that the membrane should be anchored to the upper floor ceilings.
The Antiguo Palacio del Ayuntamiento’s two main patios are covered with translucent fabric structures, each with a surface of 423m2. In order to start the construction, the project had to be approved by the INAH (National Institute of Anthropology and History). This institution rules the preservation of the historic monuments and buildings of México.
The canopies are almost equal and were based on a lineal concept of soft shapes that emphasizes the transversal main axis of the building, and at the same time follows other composition axes of columns and pinnacles. The formal design of the membranes allows different rhythms of solids and voids in the perimeter where light and air pass freely, leaving the courtyard clear from any rainwater.
The characteristic translucency of these membranes allows in sunlight, creating the effect of an open space in the interior of a courtyard and, at the same time, reducing the summer heat gain in the offices allowing a more comfortable working place for users.
The construction of the anchors, the upper structure and the erection of both membranes took place between the end of 2007 and May, 2008.
Each cover is supported by six main posts and four secondary posts, all made of 102mm diameter steel tube with galvanized finish. The main posts have poles inserted at the top in order to have an easier installation process. These posts are supported on upper-frameworks which are supported on the original steel frame of the building to minimize their impact.
Each canopy has two aluminum arches with simple section, and one double section aluminum arch made with great precision, as it was intended to be the main focal point of the design at the center of each courtyard. The double arch is covered with a transparent, independent double curved membrane that allows the direct infiltration of sunlight. These arches were made with 76mm-diameter structural aluminum tubing.
The canopies were made of Ferrari translucent membrane model 702. In order to protect the courtyard spaces from wind and rain, vertical fabric panels that are easy to install and uninstall, were added around the perimeter.