Effects of the earthquake of September 19, 2017, in homes, in the municipality of Chietla, Puebla

This work aims to publicize the effects of the 2017 earthquake on homes in the municipality of Chietla, Puebla, epicenter of the earthquake. The fieldwork was carried out by teachers and students of the Faculty of Architecture of the Benemérita Universidad Autónoma de Puebla, to support the community with a damage survey. To carry out the work, a report sheet was used where the data from the survey sheet were processed, determining the seismic analysis, the state of the construction was verified. The working groups were composed of a teacher and four students who visited each house, where images were taken, the location by latitude and longitude coordinates and the data collection. Subsequently, the information was gathered and a report was made to Civil Protection ranking the degrees of affectation. This work is the result of this field research divided into three sections. In the first part, the concepts involved in the topic are defined; the second part describes the geographical location and characteristics of Chietla; finally, the third part identifies the most common faults found in the fieldwork.

High-Resolution Observations of a Destructive Macroburst

Shortly after 0600 UTC (midnight MDT) on 9 June 2020, a rapidly intensifying and elongating convective system produced a macroburst and extensive damage in the town of Akron on Colorado’s eastern Plains. Instantaneous winds were measured as high as 51.12 m s−1 at 2.3 m AGL from an eddy covariance (EC) tower, and a 50.45 m s−1 wind gust from an adjacent 10-m tower became the highest official thunderstorm wind gust ever measured in Colorado. Synoptic-scale storm motion was southerly, but surface winds were northerly in a post-frontal airmass, creating strong vertical wind shear. Extremely high-resolution temporal and spatial observations allow for a unique look at pressure and temperature tendencies accompanying the macroburst and reveal intriguing wave structures in the outflow. At 10-Hz frequency, the EC tower recorded a 5-hPa pressure surge in 19 seconds immediately following the strongest winds, and a 15-hPa pressure drop in the following three minutes. Surface temperature also rose 1.5°C in less than one minute, concurrent with the maximum wind gusts, and then fell sharply by 3.5°C in the following minute. Shifting wind direction observations and an NWS damage survey are suggestive of both radial outflow and a gust front passage, and model proximity soundings reveal a well-mixed surface layer topped by a strong inversion and large low-level vertical wind shear. Despite the greatest risk of severe winds forecast to be northeast of Colorado, convection-allowing model forecasts from 6-18 h in advance did show similar structures to what occurred, warranting further simulations to investigate the unique mesoscale and misoscale features associated with the macroburst.

Investigation Strategy for Structural Assessment of Historic Towers

Historical masonry towers are relevant architectural heritage often in a strategic position within city centres. Their height and position require specific controls in order to define the state of preservation. The paper describes the investigation procedures developed by the authors in selected case studies. According to the timing and to the complexity of the structure, the approach requires preliminary visual inspections, geometric, crack pattern survey supplemented by historical research and stratigraphic survey. Operational modal testing evaluates the overall structural behaviour, indicating eventual local (or global) problems to study in depth by monitoring or further local tests. Emergency operations, such as controls after earthquakes, could require prompt procedures. In this case, the combination of visual inspection, geometric and damage survey with dynamic testing is a reliable procedure for structural assessment. Additional investigation increases the knowledge of local problems or gives information for further activity such as structural modelling. For instance, relevant data are the evaluation of the masonry quality or the control of the local state of stress to estimate through non-destructive or minor destructive testing in selected positions. Nevertheless, such activities require accurate projects of the investigation too, planning and localising several tests in order to solve the problems detected in the preliminary steps of the diagnosis process.

Comparison of macroseismic-intensity scales by considering empirical observations of structural seismic damage

In practice, seismic intensity is evaluated in accordance with a macroseismic-intensity scale recognized in the field of seismic engineering globally. The application of different seismic-intensity scales to evaluate the seismic damage of a specific structure due to an earthquake yields diverse results. On this basis, this study compared a few extensively used macroseismic-intensity scales. The results can be used as a reference to develop an international intensity scale. According to empirical structural-damage survey data from the Wenchuan earthquake (Mw = 8.0) that occurred on 12 May 2008 in China, the European Macroseismic Scale (EMS)-98, Medvedev, Sponheuer, and Karnik (MSK)-81, and Chinese Seismic Intensity Scale (CSIS)-08 intensity scales were utilized to evaluate the resulting damage. This study carried out a vulnerability analysis of typical structures, established vulnerability seismic-damage matrices, and mapped out vulnerability curves under different intensities. Our objective is to demonstrate that the use of multiple intensity scales can lead to very different intensity levels. The differences in the damage of typical structures under different intensity levels were obtained from an evaluation using the three aforementioned intensity scales. As a result, a calculation model of the mean damage index is proposed herein. Ultimately, this article conducted an analysis on the failure characteristics of typical structures in an earthquake and provided effective measures to improve seismic performance for future reference.

Integrated Use of Measurements for the Structural Diagnosis in Historical Vaulted Buildings

The process of the structural diagnosis of historical buildings is analyzed. The correlation of different data is a fundamental issue, related to the multidisciplinary nature of the study of built heritage. Quantitative data are collected by sensors, these being environmental data (temperature and humidity) or cracks (displacements). Another important source being qualitative data, derived from historic investigation, diagnostic investigations, etc. However sometimes the results may be difficult to correlate due to the different nature of the data, being quantitative and qualitative, as well as spread over the long life of the construction. In particular, the here proposed methodology suggests the use of light detection and ranging (LiDAR) scanning for the geometric and structural deformation survey, damage survey, historic evolution, monitoring of the crack pattern and environmental data. The integrated use of the collected data with digital and finite element models is investigated in two case studies. The combined use of the set of collected data is shown to be fundamental to the interpretation of the active damage mechanisms in the system, and for making appropriate decisions related to their safety. Finally, a guideline is proposed to allow for a more general use of the herein proposed structural diagnosis procedure.

Preliminary damage survey of school buildings and proposed plan for reconstruction of school buildings after 2015 Gorkha earthquake in Nepal

The 2015 Gorkha Earthquake (Mw = 7.8) in Nepal has devastated about 9,000 schools. The majority of damage was conceived in the peripheral districts of the Kathmandu valley. Damage distribution in the most-affected 14 districts shows that previous construction practices were an important determent for the intensity of the damage observed across these districts. The use of improper construction materials, lack of construction supervision and non-compliance with existing building codes during design and construction contributed to most of the school buildings to be severely or fully damaged. In addition to the physical damage to infrastructure, there is a significant psychological impact in terms of the effect that the disaster had on the mental health of on the school-going children, their parents and teachers within the affected areas. Preliminary damage assessment results show that in the most-affected districts, about 86% schools have been affected by the earthquakes and about one million students have been or still are out of schools for a longer period of time as a result of this. Preliminary data shows that about 30% classrooms are collapsed, about 13% classrooms are major damaged, and about 17% are minor damaged with in the most-affected 14 districts. This evidences of losses and damages from the earthquake provides an opportunity to learn lessons for future preparedness to encounter the challenge of disaster. This paper attempts to identify the needs to be addressed for the reconstruction of school buildings after 2015 Gorkha Earthquake in Nepal.