Structural Design of the New Roof for the Aztec Temple Casa De Las Águilas

This paper contains the considerations, structural analysis, and design of a new roof for the Casa de las Águilas temple, on the Templo Mayor archaeological site in Mexico City. Built around 1982, with the aim to protect the remains of the Aztec temple from sunlight and weather conditions, the previous tridimensional steel truss roof protected the site until April 28th, 2021, when a massive hailstorm caused its collapse. Fortunately, no significant damage was made to the archaeological remains. Forensic analysis was made to determine the cause of the collapse, resulting that the steel elements of this structure did not have the sufficient strength to resist the design loads, and failed in the tension elements due to overload. A new structure was projected,. On the evening of April 28th, 2021, the tridimensional steel truss roof that covered the Casa de las Águilas collapsed due to the accumulation of ice during a hailstorm. The structure, rectangular in a floor plan, and with supports on the north and on the south, behaved like a simply supported beam, with a uniformly distributed load. The maximum forces were presented at the midspan. The structure fractured on the tension members in the lower chords, creating an additional hinge that made the structure unstable. The structure collapsed like an open book, with two planes divided at the center. Forensic analysis was initially made to determine the cause of the collapse of the original roof, aimed to prevent this to happen in the new structure. With the results and the specifications created by the National Institute of Anthropology and History (INAH), the design of the new structure was made. Seismic, wind and hailstorm loads were considered. Tests were made to verify the strength of the connections.