The September 19, 2017 earthquake (Mw = 7.1) struck M & eacute;xico between the states of Puebla and Morelos. The ground motion damaged buildings near the epicenter and in Mexico City, with 44 collapsed buildings and many more experiencing some level of damage. The study gathers and statistically analyzes all available information, identifying characteristics in the plan and elevation of the damaged structures. The analysis identified structural issues typically associated with damage, such as buildings with soft or flexible ground floors and corner buildings supported by reinforced concrete frames. Corner buildings often have infill walls on two sides adjacent to neighboring properties, which, when connected to columns, cause significant torsional effects. The corner effect, combined with other structural pathologies such as soft-story, irregular building shapes, and seismic amplification effects in some city regions, significantly contributed to the damage and building collapses presented during the earthquake. The results, in addition to showing damage statistics for buildings located in a corner with infill walls, showed that the facade walls in the corner provide very little lateral stiffness comparatively to the stiffness of the perimeter walls situated on the other two sides of the building, which causes significant torsion in the building. The study also revealed that corner buildings with infill walls next to low-rise buildings were significantly more at risk than those surrounded by buildings of similar heights. A non-linear analysis of a case study showed that the observed earthquake damages in corner buildings were indeed expected, given the building's seismic demands obtained with the numerical model.

This paper focuses on the performance of a braced deep excavation in soft soil based on field monitoring and numerical modeling. Laboratory tests were conducted to determine the soil parameters used in the modified Cam-Clay (MCC) model. Intelligent field monitoring means were adopted and a three-dimensional model was established. Spatial and temporal effects induced by the excavation are investigated for the deep -large foundation pit in soft soil. Deformation characteristics of the enclosure structure and the surrounding environment throughout the excavation process are presented. The behaviors of diaphragm walls, columns, the maximum wall deflection rate, ground surface settlement, and utility pipelines were focused on and investigated during the whole excavation process. Besides, the axial forces of the internal supports are analyzed. Based on the measured and simulated data, the following main conclusions were obtained: the numerical simulation results are in good agreement with the measured values, which proves the accuracy of the model parameters; the wall and the ground surface showed the maximum displacement increment at stage 9, which was a coupled product of the creep effect of the soft soil in Nanjing, China and the depth effect of the excavation; as the excavation progressed, the ground settlement changed from a rising to a spoon -shaped trend, 6 vm was measured between 6 vm = 0.0686% H and 6 vm = 0.1488% H ; the rebound deformation curve of the pit bottom was corrugated, and the depth of disturbance of the pit bottom after the completion of soil unloading was 2-3 times the excavation depth; the closer the pipeline is to the corner of the pit, the less the excavation process will affect the settlement of the pipeline and the less the obvious pit corner effect will occur; the support strength of the buttress and the longest corner brace should be strengthened during the actual construction process to ensure the stability of the foundation deformation.