This paper investigates the behavior of a transfer slab system used in medium rise building. For this purpose, two slab-wall full-scale specimens were designed, built, and tested to cyclic loads. The two slab-wall prototypes were exposed to three load stages: (a) vertical load, (b) horizontal load, and (c) vertical and horizontal combined load. The first specimen, SP1, includes a masonry wall situated on top of a squared two-way slab of 4.25 m by side, thickness of 12 cm, on four reinforced concrete girders, while the second specimen, SP2, consists of an identical slab but was constructed with a reinforced concrete wall. Some numerical finite element slab-wall models were built using linear and nonlinear models. The most important results presented herein are the change on lateral stiffness and resistance capacity of the load-bearing wall supported on a slab versus the wall supported on a fixed base and the effects that these walls cause on the slabs. During the experimental test process of horizontal loading, we detected that the stiffness of the two slab-wall systems decreased significantly compared to the one on the fixed base wall, a result supported by the numerical models. The models indicated suitable correlation and were used to conduct a detailed parametric study on various design configurations.
This article presents a seismic vulnerability and risk assessment of buildings in Mexico City. A probabilistic seismic hazard analysis (PSHA) was carried out, which allowed the definition of seismic hazard curves as well as uniform hazard spectra (UHS) for several seismic zones. The seismic hazard includes the effects of all seismic sources located in an influence area with a radius of 500 km. Attenuation relationships were selected with basis in attenuation models of events affecting the areas of Central Mexico and were complemented by our own functions that include local soil effects. Already established the sources and attenuation functions, the seismic hazard is quantified throughout UHS, which calculated using a return period Tr = 100 years. For the vulnerability assessment, fragility curves were defined. Two groups of fragility curves were studied, the first for the first for buildings built before 1985, and the second for buildings built after 1985. In the first case, static nonlinear analyzes of selected buildings were performed to define the capacity spectra. In the second case, the capacity spectra were defined from design spectra of the Mexico City Building Code. The results showed a very good correlation with the seismic demands of the 2017 earthquake.
Part of the book: Natural Hazards