Sistema Regional de Información
en línea para Revistas Científicas de América Latina,
el Caribe, España y Portugal

Despite past failures related to industrial policy, most Latin American countries see the regional perspective as a viable alternative for innovation policy. This paper explores how regional innovation policy is implemented in some regions of Lain America. The study considers 14 regions located in 4 countries: Argentina, Colombia, Chile and Peru. The study analyzes the perceptions of experts about the policy instruments implemented in each region and the regional capacity to implement their own initiatives. The results show that different types of instruments are implemented; however, the capacity to implement regional policies differs among them, and the policy at national level could affect it. It is concluded that the regional innovation policy needs the political empowerment of local territories and the management of geographical and non-geographical aspects. Likewise, the technological aspect could be key when local territories have low political empowerment.

Northern Baja California (NBC) is characterized by two subregions: Peninsular Ranges of Baja California (PRBC) and Mexicali Valley (MV). In NBC, there are cities whose population could benefit from the operation of an Early Earthquake Warning System (EEWS). To implement an EEWS in NBC, which allows issuing notifications to warn people about the arrival of seismic waves generated by relevant earthquakes in NBC, we evaluated the capacity of response of the CICESE Seismological Network (CSN). The seismic signals from stations of this network are sent to the processing center, located at CICESE, using different transmission media. Commercial and cellular Internet modem transmissions with low latency times (< 2 s) stand out. We evaluated the performance of the CSN using the SeisComP3 acquisition and detection system in combination with the Virtual Seismologist (VS) method. This evaluation began in April 2017 and resulted in more than 5,000 earthquakes (2.0 ≤ M ≤ 5.0) recorded and processed with SeisComP3/VS. Based on the current geographical coverage of the network and the area of occurrence of a relevant earthquake, the EEWS could notify the population up to 20 seconds in advance. There is good coverage for earthquakes occurring in the VM, and notifications can be sent to cities such as Ensenada and Tijuana but not to Mexicali. For PRBC earthquakes, it is impossible to issue a prior notice to any of the towns mentioned due to insufficient station coverage. However, we consider the implementation of an EEWS for NBC feasible if the geographical coverage of the CSN stations is improved and transmission schemes with low latency times are used.

The construction regulations of the municipality of Veracruz indicate that to carry out the earthquake design of structures use the CDS-MDOC-2015, which specifies using Regional Transparent Spectral (ETRs) for the design of conventional structures (ECs). To build the ETRs, the CDS-MDOC-2015 indicates to perform a basic exploration of the subsoil enforcement a set of requirements, that make it not economically feasible to carry out for ECs. Therefore, this study proposes a procedure that results from modifying the way in which site effects are characterized in the procedure recommended in the CDS-MDOC-2015 for the construction of Site-Specific Spectrum (EESs). In the regulatory procedure the site effects are characterized by a theoretical transfer function (FTT), while in the proposed they are characterized by H/V spectral quotients obtained from environmental vibration registers, the cost of which is less than the cost of an FTT and less than the cost of conducting basic subsoil exploration. Therefore, the proposed procedure is feasible to apply, with certain limitations, to build both EESs and ETRs for ECs design. This procedure is applied to construct an ETR in the Veracruz-Boca del Río conurbation, and from its comparison with the normative ETRs it was observed that these underestimates the seismic demands in almost the entire interval of periods.

The Bay of Campeche is located in a region of moderate to high seismic activity related to the active triple junction between the North American, Caribbean, and Cocos plate boundaries. Therefore, the fixed offshore platforms and subsea structures in the Bay of Campeche must be designed against earthquake loading. A database was developed of classification and index properties tests, in situ measurements of shear wave velocity (Vs) using downhole P-S suspension seismic velocity logging, in situ piezocone penetration tests, resonant column tests to characterize the shear modulus and material damping ratio at small shear strains (10−5 % to about 0.1 %), and strain-controlled cyclic direct simple shear tests to evaluate the decrease of shear modulus and the increase of material damping ratio at large shear strains (0.1 % to about 10 %) performed on sand from the Bay of Campeche, including sands with no carbonate content to 100 % carbonate content, retrieved from the seafloor to a penetration depth of 120 m below seafloor. The database was tailored specifically to develop empirical correlations for the Bay of Campeche sand to determine Vs when in situ measurements of Vs are not available and to develop numerical modeling to predict the variation of the normalized shear modulus (G/Gmax) and material damping ratio (D) as a function of shear strains (g) when dynamic test results are unavailable for all the sand layers. The equations developed to calculate Vs and the curves of G/Gmax-g and D-g of Bay of Campeche sands are recommended for preliminary or perhaps even final seismic site response evaluations.

Codified regulations for earthquake resistant design in Mexico City during the last years (2004, 2017, 2020) specify corrective factors that must be applied to the response spectra adopted for the design of irregular buildings. The requirements adopted to consider that a building structure is regular are essentially based on the experience derived from observations about the behavior of such systems, subjected to previous high-intensity seismic excitations. According with these requirements, a structure is classified as irregular if it does not comply with one or several of these requirements. In order to take into account the influence of the degree of irregularity on the spectral ordinates that must be adopted to achieve a performance level similar to that corresponding to a regular system of equal fundamental period, a set of corrective factors are specified, to be applied to the response reduction factor Q'. These values were established on the basis of engineering judgement; therefore, it is necessary to revise them on the basis of seismic response studies oriented to attaining in the irregular systems reliability levels that are consistent with those implicit for their corresponding reference regular systems.  This study is focused on irregular buildings, characterized by plan dimension variable along their height, which lead to variable torsional eccentricities along it. A new criterion is established for the determination of reliability functions of buildings with the mentioned types of irregularities; they are applied to several specific cases to be used as basis for the development of parametric studies about the influence of different global properties on the corrective factors necessary to generate seismic design spectra leading to equal reliability levels.

This paper describes the effects of some seismic motions in buildings of the city of Morelia, Michoacan, the urban morphology, soil characteristics, local seismic faults and the evolution of seismic design parameters proposed in local regulations. The importance of the Nicolaita Seismic Network, composed of 10 accelerometric stations, in recording the seismic movements to mitigate the seismic risk is pointed out. Currently, the recorded accelerograms have shown significant differences in the ground motion that must be considered when conducting a seismic hazard assessment. The paper also presents some recorded accelerograms and response spectra. The objective of this manuscript is to show that, according to the seismic history and the damage caused by past seismic events, the city of Morelia is a site prone to destructive earthquakes, which makes it essential the seismic network.

Typically, the seismic analysis and design of structures considers exclusively the seismic horizontal components, and only in certain cases, the vertical movement is also incorporated in the analysis. A common way to include the vertical seismic demand is by means of a vertical design spectrum having ordinates equal to the ordinates of the horizontal design spectrum reduced by a factor less than one. However, observations from earthquake records have revealed that vertical component of ground motions is especially significant for high frequency content and sites located close to the epicenter, where the vertical acceleration can be even greater than the horizontal components, driving to the conclusion that the reduction of the horizontal spectra as a way to represent the vertical seismic demand is not appropriate. The first aim of this study is to assess the importance of the vertical component by conducting a parametric study of 100 records associated to the subduction process, obtained from the Mexican Strong Motion Database. The acceleration time histories were recorded at distances less than 60 km and for magnitudes larger than 5.0. The second part is focused on the influence of the horizontal and vertical components of ground motions on the structural response of bridges during their staged construction process and also of completed bridges by means of a nonlinear analysis.            

This paper compares the structural reliability of a reinforced concrete building for office use located in the soft soil of Mexico City, using two different structural systems. The first one is based on reinforced concrete moment resisting frames (conventional system) and the second one incorporates shear walls strategically located in the exterior frames (dual system). Complex structural models are used for both buildings, which are subjected to several seismic records of the soft soil in order to estimate and compare the reliability of both systems using demand hazard curves. It is important to say that a comparison of the results obtained from the design of the two structural systems in terms of other engineering demand parameters is also studied. The parameter used to estimate the structural reliability is the maximum inter-story drift, which is obtained through incremental dynamic analyses in order to compute seismic fragility curves.  The estimation of structural reliability is assessed by means of probabilistic models by combining the fragility and seismic hazard curves. Finally, the results obtained show that the use of dual system can be a good design alternative, providing a more economical solution and a better seismic behavior. 

En este artículo se discute la respuesta sísmica de marcos de acero con conexiones de viga I al eje menor de la columna. Se realizaron pruebas experimentales sometidas a demandas cuasi-estáticas en escala natural. Las conexiones reportan una concentración de daño gobernada por el pandeo local de los patines, por lo que se analiza la distribución de esfuerzos y el fundamento de los criterios normativos para mejorar su respuesta. Los resultados experimentales se comparan considerando un modelo de elemento finito y modelos detallados de plasticidad distribuida en el programa OpenSees. Adicionalmente, se obtuvo la curva envolvente de las pruebas para calibrar los criterios normativos para la predicción inelástica en manuales especializados de análisis no lineal.

In this paper, a probabilistic methodology to estimate fundamental decision variables of the theory of seismic resilience of buildings is presented: repair costs, repair time, recovery time and number of workers needed to perform the rehabilitation works. The proposed evaluation scheme is based on the recursive PERT method and is consistent with the probabilistic methodology for evaluating performance proposed by PEER and with the concept of resilience developed by MCEER. To illustrate the methodology, the evaluation of a seven-story reinforced concrete building with unreinforced masonry infill walls and designed in accordance with the Complementary Technical Norms – Seismic Design (2020) is presented. This structural system is typical of office buildings. The proposed methodology can be used to increase the seismic resilience of buildings, and to establish mitigation and recovery strategies not only for individual buildings, but also for groups of buildings.