Case Study of a Heavily Damaged Building during the 2016 MW 7.8 Ecuador Earthquake: Directionality Effects in Seismic Actions and Damage Assessment

In this work, the directionality effects during the MW 7.8 earthquake, which occurred in Muisne (Ecuador) on 16 April 2016, were analyzed under two perspectives. The first one deals with the influence of these effects on seismic intensity measures (IMs), while the second refers to the assessment of the expected damage of a specific building located in Manta city, Ecuador, as a function of its azimuthal orientation. The records of strong motion in 21 accelerometric stations were used to analyze directionality in seismic actions. At the closest station to the epicenter (RRup = 20 km), the peak ground acceleration was 1380 cm/s2 (EW component of the APED station). A detailed study of the response spectra ratifies the importance of directionality and confirms the need to consider these effects in seismic hazard studies. Differences between IMs values that consider the directionality and those obtained from the as-recorded accelerograms are significant and they agree with studies carried out in other regions. Concerning the variation of the expected damage with respect to the building orientation, a reinforced concrete building, which was seriously affected by the earthquake, was taken as a case study. For this analysis, the accelerograms recorded at a nearby station and detailed structural documentation were used. The ETABS software was used for the structural analysis. Modal and pushover analyses were performed, obtaining capacity curves and capacity spectra in the two main axes of the building. Two advanced methods for damage assessment were used to obtain fragility and mean damage state curves. The performance points were obtained through the linear equivalent approximation. This allows estimation and analysis of the expected mean damage state and the probability of complete damage as functions of the building orientation. Results show that the actual probability of complete damage is close to 60%. This fact is mainly due to the greater severity of the seismic action in one of the two main axes of the building. The results are in accordance with the damage produced by the earthquake in the building and confirm the need to consider the directionality effects in damage and seismic risk assessments.

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Damage Probability Assessment of Hospital Buildings in Yogyakarta, Indonesia as Essential Facility due to an Earthquake Scenario

Journal of the Civil Engineering Forum ◽

10.22146/jcef.53387 ◽

2020 ◽

Vol 6 (3) ◽

pp. 225

Author(s):

Yunalia Muntafi ◽

Nobuoto Nojima ◽

Atika Ulfah Jamal

Keyword(s):

Response Spectra ◽

Prediction Equation ◽

Building Damage ◽

Damage State ◽

Ground Acceleration ◽

Damage Level ◽

Earthquake Scenario ◽

Capacity Curves ◽

Damage Probability ◽

Essential Facility

Indonesia is a country located in an earthquake-prone region, and is characterized by significantly increased peak ground acceleration value. The seismic hazard map of Indonesia stated in SNI 1726-2012 and the current statistics published by PUSGEN in 2017 emphasized on the significance of assessing building damage probabilities, especially for essential structures in Yogyakarta. However, immediate action is required to handle response and recovery operations during and after a disaster. The aim of this study, therefore, is to ascertain the vulnerability and damage probability of hospital buildings in Yogyakarta by employing the 2006 earthquake scenario, where reports showed the destruction of over 156,000 houses and other structures. Furthermore, a Hazard-US (HAZUS) method was used for structural analysis, while a ground motion prediction equation was adopted to produce the building response spectra, following the characteristics of the earthquake incidence. The vital step in this assessment involves building type classification and identification of seismic design levels. However, the damage tendency of buildings is determined using the peak building response, which ensures the generation of capacity curves. The most significant findings on building damage probability value were less than 15% in each damage state (slight, moderate, extensive, complete). In addition, the optimum value was achieved at the minimum level of damage (minor), while the least values were recorded at the highest damage level (complete).

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Study on the Ground Response Analysis for Stiff Soil

Advanced Materials Research ◽

10.4028/www.scientific.net/amr.915-916.122 ◽

2014 ◽

Vol 915-916 ◽

pp. 122-125

Author(s):

Xiao Fei Li ◽

Rui Sun ◽

Xiao Bo Yu

Keyword(s):

Seismic Response ◽

Working Conditions ◽

Strong Motion ◽

Response Spectra ◽

Response Analysis ◽

Seismic Response Analysis ◽

Ground Response Analysis ◽

Ground Acceleration ◽

Strong Motion Records ◽

Stiff Soil

In order to test the applicable of the seismic response analysis procedures SHAKE2000 and LSSRLI-1 for class ІІ site, 17 stations and 35 underground strong motion records of KiK-net are selected from Class ІІ site. 210 working conditions are used to verify the applicability of the two soil seismic response analysis programs at Class ІІ site. These two programs are used to calculate the selected working conditions, giving the peak acceleration of the ground, the shear strain and the ground acceleration response spectra. By analyzing the results of the two programs and the measured results to assess the degree of difference between the two methods and which program is closer to the real situation. Studies have shown that in class ІІ site, in most cases, the results of SHAKE2000 and LSSRLI-1 differ little. While comparing with the actual records, SHAKE2000 is closer to the strong motion records.

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Application of the Incremental Modal Analysis for Bridges (IMPAb) Subjected to Near-Fault Ground Motions

10.20944/preprints202009.0023.v1 ◽

2020 ◽

Author(s):

Alessandro Vittorio Bergami ◽

Gabriele Fiorentino ◽

Davide Lavorato ◽

Bruno Briseghella ◽

Camillo Nuti

Keyword(s):

Ground Motion ◽

Ground Motions ◽

Pushover Analysis ◽

Vertical Component ◽

Vertical Motion ◽

Strong Motion ◽

Seismic Action ◽

Near Fault ◽

Benchmark Solutions

Near-fault ground motions can cause severe damage to civil structures, including bridges. Safety assessment of these structures for near fault ground motion is usually performed through Non-Linear Dynamic Analyses, while faster methods are often used. IMPAb (Incremental Modal Pushover Analysis for Bridges) permits to investigate the seismic response of a bridge by considering the effects of higher modes, which are often relevant for bridges. In this work, IMPAb is applied to a bridge case study considering near-fault pulse-like ground motion records. The records were analyzed and selected from the European Strong Motion Database and the pulse parameters were evaluated. In the paper results from standard pushover procedures and IMPAb are compared with nonlinear Response-History Analysis (NRHA), considering also the vertical component of the motion, as benchmark solutions and incremental dynamic analysis (IDA). Results from the case study demonstrate that the vertical seismic action has a minor influence on the structural response of the bridge. Therefore IMPAb, which can be applied considering vertical motion, remains very effective conserving the original formulation of the procedure, and can be considered a well performing procedure also for near-fault events.

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Study on the Comparison of Ground Response Analysis for Class І Site

Advanced Materials Research ◽

10.4028/www.scientific.net/amr.919-921.1031 ◽

2014 ◽

Vol 919-921 ◽

pp. 1031-1034

Author(s):

Xiao Fei Li ◽

Rui Sun

Keyword(s):

Strong Motion ◽

Response Spectra ◽

Response Analysis ◽

Acceleration Response ◽

Seismic Response Analysis ◽

Ground Response ◽

Real Situation ◽

Ground Response Analysis ◽

Ground Acceleration ◽

Maximum Shear Strain

In order to test the applicable of the two equivalent linear seismic response analysis procedures SHAKE2000 and LSSRLI-1 for class І site, 21 underground strong motion records were selected from 11 stations of KiK-net as input earthquake motions. By using these two programs to calculate the peak ground acceleration, soil maximum shear strain and acceleration response spectra. By comparing the results of the two procedures and the measured results to evaluate the proximity of these two methods and then judge which program is closer to the real situation. Studies have shown that in class І site, the results of SHAKE2000 and LSSRLI-1 differ little; but according to the measured records, there are some differences between the two programs results and the measured records. While no matter comparing from which side, SHAKE2000 is closer to the earthquake records.

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A Quantitative Basis for Building Instrumentation Specifications

Earthquake Spectra ◽

10.1193/1.3532840 ◽

2011 ◽

Vol 27 (1) ◽

pp. 133-152 ◽

Cited By ~ 1

Author(s):

Derek A. Skolnik ◽

Robert L. Nigbor ◽

John W. Wallace

Keyword(s):

Time Synchronization ◽

Strong Motion ◽

Sensitivity Analyses ◽

Peak Ground Velocity ◽

Ground Acceleration ◽

Rate System ◽

Intensity Measures ◽

Quantitative Basis ◽

Structural Responses ◽

High Pass

A quantitative basis for key building instrumentation specifications—namely, sample rate, system resolution, and time synchronization—is established by quantifying the sensitivities of engineering demand parameters of peak floor acceleration and peak interstory drift to the errors associated with data acquisition. Details of the realistic simulation and digitization of structural responses are provided and automation of the seemingly signal-dependent procedure of high-pass digital filtering of relative displacements obtained by double numerical integration of accelerations is presented. Results from these studies, along with prior results from similar sensitivity analyses with respect to intensity measures of peak ground acceleration, peak ground velocity, and peak spectral acceleration, are used to recommend potential updates to structural instrumentation specifications of major strong-motion instrumentation programs.

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WINSTON-BATAN: A SEISMOLOGICAL GROUND-MOTION ANALYSIS CODE

Jurnal Natural ◽

10.24815/jn.v18i3.12201 ◽

2018 ◽

Vol 18 (3) ◽

pp. 152-160

Author(s):

Yuliastuti Yuliastuti ◽

Euis Etty A ◽

Topan Setiadipura

Keyword(s):

Ground Motion ◽

Motion Analysis ◽

Time History ◽

Strong Motion ◽

Response Spectra ◽

Fast Fourier Transformation ◽

Geological Condition ◽

Design Development ◽

Ground Acceleration ◽

Motion Time

A thorough understanding of an earthquake is very important to provide a descriptive knowledge and in the same time as a prescriptive knowledge for the future development. In particular, it is essential for site selection and structural design development of nuclear reactor and other critical facilities. Ground motion acceleration time history is an important raw information to understand the earthquake and specific geological condition of where the data is recorded. This paper presented the development of strong-motion analysis code, called Winston-BATAN, which able to interpret ground motion time history. The analysis scope of the code including the ground motion parameters such as peak ground acceleration, several additional seismic intensity parameters, strong motion duration, its frequency content via Fast Fourier Transformation and response spectra analysis. Being developed based on an open source Python programming language, Winston-BATAN is flexible for exploratory study to exploit the ground motion time history and easily improve to accommodate additional features. This code able to read input from PEER NGA type file or a simple time and acceleration data type of ground motion. Analysis results of Winston-BATAN shows a very good agreement compare to the results from the standard tools Seismosignal® 2018 Software, in addition flexibility of this code, in particular, to explore the response spectra from the ground motion time history is demonstrated.

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Strong-Motion Characteristics and Visual Damage Assessment Around Seismic Stations in Kathmandu after the 2015 Gorkha, Nepal, Earthquake

Earthquake Spectra ◽

10.1193/042916eqs074m ◽

2017 ◽

Vol 33 (1_suppl) ◽

pp. 219-242 ◽

Cited By ~ 3

Author(s):

Subeg Bijukchhen ◽

Nobuo Takai ◽

Michiko Shigefuji ◽

Masayoshi Ichiyanagi ◽

Tsutomu Sasatani

Keyword(s):

Damage Assessment ◽

Strong Motion ◽

Response Spectra ◽

Period Range ◽

Seismic Stations ◽

Nepal Earthquake ◽

Visual Damage ◽

S Period ◽

Motion Characteristics ◽

2015 Gorkha Nepal Earthquake

A rapid visual damage assessment of buildings around four strong-motion seismic stations in Kathmandu Valley was carried out after the damaging Gorkha, Nepal earthquake (Mw7.8) of 25 April 2015. The waveforms of the main shock recorded at these stations were compared with the damage to buildings around the stations. The damage was found to be related to strong-motion characteristics of the earthquake. A dominance of long-period oscillation could be observed in the records. The damage to low-rise buildings in the valley was less than anticipated from an earthquake of this magnitude given that the majority of buildings were built without proper engineering consideration. The acceleration response spectra of one of the sedimentary sites show high response in the 1–2 s period range, and nearly 10% of the buildings, which were all low-rise, suffered damage around this site.

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Engineering Characteristics of Ground Motions Recorded in the 2019 Ridgecrest Earthquake Sequence

Bulletin of the Seismological Society of America ◽

10.1785/0120200036 ◽

2020 ◽

Vol 110 (4) ◽

pp. 1474-1494 ◽

Cited By ~ 2

Author(s):

Sean Kamran Ahdi ◽

Silvia Mazzoni ◽

Tadahiro Kishida ◽

Pengfei Wang ◽

Chukwuebuka C. Nweke ◽

...

Keyword(s):

Ground Motion ◽

Fault Zone ◽

Ground Motions ◽

Response Spectra ◽

Earthquake Sequence ◽

Damage Potential ◽

Ground Acceleration ◽

Intensity Measures ◽

Inelastic Response ◽

Motion Models

ABSTRACT We present a database and analyze ground motions recorded during three events that occurred as part of the July 2019 Ridgecrest earthquake sequence: a moment magnitude (M) 6.5 foreshock on a left-lateral cross fault in the Salt Wells Valley fault zone, an M 5.5 foreshock in the Paxton Ranch fault zone, and the M 7.1 mainshock, also occurring in the Paxton Ranch fault zone. We collected and uniformly processed 1483 three-component recordings from an array of 824 sensors spanning 10 seismographic networks. We developed site metadata using available data and multiple models for the time-averaged shear-wave velocity in the upper 30 m (VS30) and for basin depth terms. We processed ground motions using Next Generation Attenuation (NGA) procedures and computed intensity measures including spectral acceleration at a number of oscillator periods and inelastic response spectra. We compared elastic and inelastic response spectra to seismic design spectra in building codes to evaluate the damage potential of the ground motions at spatially distributed sites. Residuals of the observed spectral accelerations relative to the NGA-West2 ground-motion models (GMMs) show good average agreement between observations and model predictions (event terms between about −0.3 and 0.5 for peak ground acceleration to 5 s). The average attenuation with distance is also well captured by the empirical NGA-West2 GMMs, although azimuthal variations in attenuation were observed that are not captured by the GMMs. An analysis considering directivity and fault-slip heterogeneity for the M 7.1 event demonstrates that the dispersion in the near-source ground-motion residuals can be reduced.

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Developed approach to determine the seismic vulnerability of reinforced concrete structures

MATEC Web of Conferences ◽

10.1051/matecconf/201814902078 ◽

2018 ◽

Vol 149 ◽

pp. 02078

Author(s):

Serraye Mahmoud ◽

Amri Salima

Keyword(s):

Seismic Vulnerability ◽

Fragility Curves ◽

Response Spectrum ◽

Response Spectra ◽

Seismic Intensity ◽

Point Of View ◽

Damage State ◽

Capacity Curves ◽

Performance Point ◽

Materials Used

Several evaluation methods of the seismic vulnerability have been developed around the world. Which are very use ful from humanitarian and socioeconomic point of view. Generally these methods use knowledge obtained from previous earthquakes and they are basing on seismic intensity scales and on buildings direct observation. But the macroseismic intensity expresses the consequences of the seism, and not its physical characteristics of the structures. Contrary to this type of methods, an approach based on a nonlinear analysis (Push-Over method) is proposed in this work. It consists in modeling the excitation of the earthquake by a response spectrum and building's behavior by capacity curves. These capacity curves are obtained from numerical modeling performed by Opensees software. The superposition of the two curves, response spectra and capacity curve, makes it possible to determine the performance point and consequently to deduce the state of expected damage. To estimate the probability of damage of a building at a given level of solicitation (defined by Sd), we excites a group of buildings characterized by different parameters related to the geometry of the building and those are related to the materials used (concrete, steel) by seismic solicitation (Response spectrum - RPA 99). The performance point for each building is determined by a procedure defined in FEMA 440. We classifies the buildings according to the position of performance point on their curve which defines a damage state of ds (Mild, Moderate, Important or Ruin) according to the damage levels of Risk-UE. A statistical analysis is then made for each class to build the fragility curves.

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Application of the Incremental Modal Pushover Analysis to Bridges Subjected to Near-Fault Ground Motions

Applied Sciences ◽

10.3390/app10196738 ◽

2020 ◽

Vol 10 (19) ◽

pp. 6738

Author(s):

Alessandro Vittorio Bergami ◽

Gabriele Fiorentino ◽

Davide Lavorato ◽

Bruno Briseghella ◽

Camillo Nuti

Keyword(s):

Ground Motion ◽

Pushover Analysis ◽

Vertical Component ◽

Structural Response ◽

Strong Motion ◽

Seismic Action ◽

Modal Pushover Analysis ◽

Near Fault ◽

Modal Pushover

Near-fault events can cause severe damage to civil structures, including bridges. Many studies have demonstrated that the seismic assessment is not straightforward. Usually, dealing with near-fault ground motion, the structural analysis is performed using Nonlinear Response-History Analysis (NRHA) but in the last years, many authors have tested existing pushover-based procedures originally developed and validated using far-field events. Between those procedures, the Incremental Modal Pushover Analysis (IMPAβ) is a pushover-based procedure specifically developed for bridges that, in this work, was applied to a case study considering near-fault pulse-like ground motion records. The records were analyzed and selected from the European Strong Motion Database. In the paper the results obtained with IMPAβ together with other standard pushover procedures, are compared with NRHA and incremental dynamic analyses; the vertical component of the motion has been also considered. Results obtained with the bridge case study demonstrate that the vertical seismic action has a minor influence on the structural response and that IMPAβ is confirmed as a very effective pushover-based method that can be applied also for near-fault events.

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