Karstic zones, due to dissolution of limestone rocks, are a problem in several areas of the world, being associated with damage sustained by facilities, among other issues. A numerical study is presented using Plaxis 2D to analyse terrain subsidence on the surface, considering a transversal section to apply a road load, while cavities in the ground increase due to karsticity. Results allow perception of the surface subsidence, associated with the number of cavities, before and up to collapse of the first voids created. Stress paths developed in the cavities’ opening process are built from the interpretation of results provided by the numerical analyses. These stress paths make it possible to obtain the way in which stress values change between initial and final states, defining an in situ stress variation for the void's presence. Furthermore, it is concluded that there is a tendency towards stability for the superficial displacement and a maximal affected horizontal length associated with a specific number of cavities, despite the fact that more of these are developed in the zone. The rocks and the soil were simulated by Hoek–Brown and Mohr–Coulomb constitutive models, considering the specific characteristics of rocks and soil endemic to Yucatan, Mexico.

In Mexico, since the early stages of the civilization, the stone masonry has assumed an important role in construction due to the wide availability of this kind of material. Masonry is a material composed by bricks, carved or even rubble stones jointed without (dry joint) or with mortar (mortar joints); which is principally formed with sand, water and cementitiuos materials. The research presented in this paper deals with the procedure of obtaining the mechanical properties of rocks placed on piers of four vehicular bridges located in the south of the state of Mexico, these mechanical properties are compressive strength, modulus of elasticity, Poisson ratio, Cohesion and Internal friction Angle of the rocks as independent units, also are reported the Density values. All of these properties are necessary to conduct further research regarding the mechanical behavior of the pier as a structure since this piece of research is part of an ongoing project concerning risk assessment of vehicular bridges developed in Mexico. The identified rocks in masonry were volcanic igneous materials such as dacites, basalts, rhyolites, andesites and rusted andesites. The materials with the highest and the lowest mechanical properties are the basalt and the dacite respectively. It is recommended to use the dacite’s properties in order to perform a conservative analysis of the mechanical behavior of any masonry structure, located near the selected sample studied herein.

One of the responsibilities of a Civil Engineer is to make decisions regarding preservation of infrastructure; therefore, there have been established concepts such as risk and risk analysis. Risk analysis, is a methodology applied to determine and evaluate the risk magnitude. From the structural engineering point of view, it is required that any structure become secure, this means that the capacity to withstand external actions (strength) will be higher than these actions (loads). In order to determine the structural safety, it is required to define the failure of the structure that it is not strongly related with the collapse of the structure; the failure criteria needs to be fixed depending on the use of the building and the consequences associated with the interruption of services provided by the facility. The failure then, is calculated by means of a limit state function in where it is established the failure criteria; failure is reached when a specific condition (strength) is surpassed by the actions over the structure. The present work aims to propose a preliminary Finite Element Model (FEM) that represents a pier used as support for vehicular bridges. This FEM is required for the assessment of mechanical behavior of the structure that will be used for the determination of the limit state function needed for risk assessment. Most of the simulations with FEM presented in literature are very used for modeling of masonry walls, but it is not usual to model structures such as bridge piers.

Urban areas built on old lacustrine basins in central Mexicoshow subsidence related to creep-fault processes. These processes are highly dynamic and enhanced by aquifer water extraction and El Niflo events. The affected cities are Morelia, Salamanca, Silao, Celaya, Aguascalientes, and Querdtaro, with a global population of around 2.5 million, and considerable industrial assets. The first three cities show NE-SW creep-fault trends, while in the remaining the trend is N-S. The subsidence rate varies: 2-3 cm/year at Salamanca, 4-6 cm/year at Morelia and Querdtaro, and 6-8 cm/year at Celaya. In order to preliminarily evaluate the effects of the creep-faults, we performed a series of nondestructive ground penetrating radar surveys in the city of Morelia, that complement concurrent geological studies of the area. We report herein results in three locations where the surface expression of the faults is well defined, including substantial damage to homes and buildings. One of the objectives was to determine the length of the disturbance, perpendicular to the faults' trends. Using 50 Mhz antennas we reached an exploration depth of around 10 m in sandstone-bearing lacustrine deposits and lava flows.In most cases the faults show low-angle dips that vary with depth in the main fault. Additional, synthetic and antithetic faults are developed in the disturbed area of the main fault, which we define as the influence zone of the main disturbance. We find that this zone varies from 15 to 50 m on both sides of the fault, although it tends to be larger on the down thrown block. Faulting appears to be controlled by geological formations within the first 10-15 m in depth.

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