Sergio Diaz

• Ph.D.
• Professor at Universidad Juárez Autónoma de Tabasco

This research presents an experimental analysis of the mechanical behavior of masonry mortars incorporating disposable face masks (FMs) cut into two different sizes. The objective is to provide experimental data contributing to the consolidation of recycling FMs in mortar mixtures. To achieve this, two types of mixtures were prepared: one with stri...

Precipitation is a fundamental component of the Earth’s hydrological cycle. Therefore, monitoring precipitation is paramount, as accurate information is needed to prevent natural hydrological disasters, such as floods and droughts. However, measuring precipitation using rain gauges is complicated due to their sparse spatial distribution. Satellite...

Seismic risk management in urban areas requires accurate prediction of the expected seismic hazard. The seismic design standards in the world provide the seismic design spectra (DS). These are crucial for estimating seismic forces on a structure, are typically derived from theoretical models in deterministic or probabilistic seismic hazard studies,...

In this research, the use of the pre-wetting technique is proposed as an ecological alternative to reduce water absorption in waste oyster shells used in the production of masonry mortar as a partial substitute for natural sand. An experimental study was conducted to assess the properties in both the fresh and hardened states of masonry mortars. Tw...

Se presenta un estudio en que se evalúa la vulnerabilidad sísmica de 74 viviendas de 13 manzanas del núcleo urbano de Siltepec, Chiapas, México. Para este fin, se emplean dos métodos: 1) el basado en la clasificación tipológica según la Escala Macrosísmica Europea (EMS-98) y, 2) el del Índice de Vulnerabilidad Sísmica (MIV) de RISK-UE. El segundo m...

During strong earthquakes, structural damage usually occurs, resulting in a degradation of the overall stiffness of the affected structures. This degradation produces a modification in the dynamic properties of the structures, for instance, in the fundamental period of vibration (T1). Hence, the variation of T1 could be used as an indicator of seis...

El daño esperado en las edificaciones por los sismos se puede determinar con la máxima distorsión de entrepiso (max) y depende del tipo de edificio y de las características del sismo. En esta investigación se presenta un nuevo índice del potencial del daño (IPDSaT1-IA-ΔIA) de los sismos, basado en su intensidad de Arias (IA), la duración significa...

In this research, the mechanical behavior of masonry mortars made with partial substitution of sand by recycled fine aggregates (RFAs) of mortar (MT) and recycled clay brick (RCB) was compared. Mortar specimens were built in two groups (MT and RCB) considering different replacement proportions by dry weight. To reduce the water absorption of RFAs d...

The seismic regulations for the seismic performance assessment of buildings use the maximum interstory drift, θmax, as a measure to control damage. This article presents a study of the seismic performance based on the θmax for steel buildings using Mexico's regulations and the RISK-UE and HAZUS guidelines. The capacity spectrum method is used to ev...

In this research we evaluated the use of recycled fine mortar aggregate (RFMA) as a fine aggregate for new masonry mortar creation. The pre-wetting effect on the aggregate before creating the mixture was analyzed as a method to reduce its absorption potential. A control mixture of conventional mortar and two groups of recycled mortars were designed...

In Costa Rica, typical dwelling constructions are generally built with reinforced concrete masonry walls. This construction practice became one of the most common during the second half of the last century in Costa Rica. These kinds of structures exhibit high lateral stiffness and shear capacity, which makes them susceptible to semi-ductile failure...

Recycling is an important habit to avoid waste. This paper evaluates the performance of masonry mortar, elaborated by replacing natural sand with recycled fine aggregate (RFA) obtained from mortar. Five families of mixtures were prepared with different replacement proportions: 20%, 40%, 60%, and 100%. A 1:4 volumetric cement-to-aggregate ratio was...

Estimations of seismic risk in urban areas should include quantifications of the expected damage to civil structures subjected to earthquakes. In buildings, this quantification depends on the maximum inter-story drift (MIDR), among other aspects. In this study, the correlation between several intensity measures (IMs) and the maximum inter-story dri...

Durante la época de lluvias se presentan en el estado de Tabasco (México) deslizamientos en los bordos de los ríos que atraviesan la entidad, siendo los de la zona conocida como La Manga de los más afectados. Este artículo presenta el análisis de la evolución de la estabilidad de uno de estos bordos debido a los cambios en el grado de saturación de...

Durante la ejecución de obras de ingeniería es común que el suelo que se desea utilizar no cumpla con los criterios de calidad que la normativa correspondiente exige para garantizar la estabilidad estructural de la obra. Para aquellos casos en los que el valor del índice de plasticidad del suelo excede el máximo permitido, la estabilización química...

Recent research have proven the importance of considering the directionality effect on the expected seismic damage of structures. However, it demands a high computational effort if the nonlinear dynamic analysis (NLDA) is used to estimate the seismic response. This paper presents a simplified approach to obtain peak response parameters for a buildi...

Recent researches have proven the importance of considering the seismic directionality effect. The performance of buildings subjected to earthquakes depends on its orientation respect to the seismic actions applied. This type of calculation is computed using the nonlinear dynamic analysis (NLDA) and rotating the acceleration horizontal components o...

Recent researches have proven the importance of considering the seismic directionality effect. The performance of buildings subjected to earthquakes depends on its orientation respect to the seismic actions applied. This type of calculation is computed using the nonlinear dynamic analysis (NLDA) and rotating the acceleration horizontal components o...

Directionality effects on the expected strong ground motion in Italy are investigated. After a brief description of the directionality effect and the intensity measures involved, a wide Italian database of strong ground motion records is used, with a total of 949 horizontal accelerograms (two components). The analysis is performed for 5% damped res...

We analyze the case of a building that collapsed in a multifamily complex of Tlalpan borough in Mexico City during the 19 September 2017 Central Mexico earthquake. Despite having similar materials and similar structural and geometric properties, this was the only building that collapsed in the complex. A structural analysis of the building and a st...

Currently, worldwide, many nations are paying close attention to the improvement and optimization of the usage of recycled materials in the building sector. The increase in the raw materials and the increased environmental awareness have gained considerable importance on a global scale. In road engineering, the waste material is used for the design...

Structures with high lateral stiffness and/or with brittle to semi-brittle elements in their lateral resistant system may exhibit a rapid decrease of their shear capacity and a sudden loss of stiffness when lateral cyclic loads, as those produced by earthquakes, are applied. This behavior can be related to damage (partial or complete) of a particul...

Las estructuras que emplean paredes de mampostería se caracterizan por tener una gran rigidez y capacidad ante cargas paralelas a su plano debido, principalmente, a la gran inercia de algunos elementos que la componen. Bajo condiciones usuales, se dice que los elementos de mampostería, con o sin refuerzo, poseen un comportamiento frágil ante cargas...

Recently proposed capacity-based damage indices and parametric models for capacity curves are applied to frame steel buildings located in soft soils of the Mexico City. To do that, the seismic performance of 2D models of low-, mid- and high-rise buildings is assessed. Deterministic and probabilistic nonlinear static and incremental dynamic analyses...

Most of buildings and structures are usually projected according to two main axes. However, the geographical position of these buildings varies randomly. Such random distributions of the azimuthal positions of structures, in most of the cities, generally, are not accounted for when assessing their seismic risk; certainly, the direction of the seism...

El principal objetivo de esta tesis es la evaluación probabilista del daño esperado en edificios de acero sometidos a las acciones sísmicas de diseño de la Ciudad de México, considerando los seis tipos de suelo en qué está zonificada la ciudad. Así, aunque se efectúa también un análisis determinista, tanto la acción sísmica como los edificios se co...

Non-linear dynamic analysis and the damage index of Park-Ang have been often used to assess expected seismic damage to a structure. Depending on the size of the structure and the duration of the record, the computational effort in dynamic analyses is usually high. In this research, a new damage index is proposed based on nonlinear static analysis....

The probabilistic analysis of the seismic performance of a structure requires quantifying the uncertainties of the involved variables and parameters, including the seismic action and mechanical properties of its elements. In this article, the seismic performance of high-rise, mid-rise and low-rise of steel buildings, subjected to long duration seis...

Ground Motion Prediction Equations commonly use response spectra as input data. However, the selection of a unique spectral function which minimizes the error between predicted and observed values, remains a subject of research. Recently, response spectra independent of the sensors orientation have been used in seismic hazard studies, showing a red...

The capacity and expected seismic damage of several types of steel buildings are assessed. Nonlinear static structural analysis and incremental dynamic analysis (IDA) by means of a probabilistic approach with Monte Carlo Simulation are used. For static analysis, an important contribution of this paper is to extend the parametric models and damage i...

The assessment of damage caused by earthquakes in structures, requires the use of nonlinear analysis, either static or dynamic, in order to define the performance of the buildings for the considered hazard levels. In this paper, different damage models based on static and dynamic nonlinear analysis are used in the evaluation of a low-rise building...

The capacity and expected seismic damage of several types of steel buildings are assessed by using a probabilistic approach. Nonlinear static and dynamic analyses are performed by means of Monte Carlo Simulations. Concerning to the nonlinear static approach, it is shown that new damage model, recently developed for reinforced concrete buildings, al...

In this research the influence of the directionality of the recorder instruments on the estimation of the maximum ground motions is analyzed; that means that the geometric mean as a measure of ground motion intensity for the same earthquake, depends on the orientation of the recording sensors. A procedure recently developed allowing to take into ac...

The seismic intensity measures based on acceleration, are used to define attenuation laws and in seismic hazard analysis. Usually, these measures are defined in terms of the acceleration response spectra of two horizontal accelerograms, performing different combinations of the spectral components, although the geometric mean is the most commonly us...

Se aborda el efecto de direccionalidad de los terremotos en la amenaza de la Ciudad de México. Esto significa que la media geométrica (GM) como medida de intensidad del movimiento sísmico, para un mismo sismo, depende de la orientación del registro. Se determinaron de 1277 registros sísmicos del Distrito Federal, la GM de los espectros de respuesta...