The building that houses the NH Reforma hotel in Mexico City has 18 floors and was built in 1969. It has adequately supported and withstood numerous earthquakes, some of great intensity, and has undergone corresponding repair interventions after each of them.

On September 19, 2017, an earthquake with a magnitude of 7.1 occurred with an epicenter near Mexico City. As a result of this earthquake and the damage it caused to the building, NH commissioned inspections, movement measurements, structural and geotechnical evaluations, as well as environmental vibration tests to characterize the natural modes of vibration.

The objective of the project was to identify the elements damaged by the earthquake and develop a series of actions aimed at restoring the structure to its original resistant and rigid characteristics, avoiding actions that would significantly increase the rigidity of the affected elements, as this would modify the seismic response of the structure.

The main action consisted of proposing a foundation underpinning that would stabilize the building’s presented collapses and reduce settlements, affecting the hotel’s operation as little as possible during its execution. In the study of solutions, driven solutions, load bridging, and ground improvements were considered, with the latter being the solution ultimately proposed. The jet grouting technique was considered the most suitable due to compatibility with the existing clayey soil and implementation feasibility. 110 jet grouting columns were proposed, forming a grid with a side length of 4.20 meters.