Table 1
Context in source publication
Context 1
... accelerograms of the Whittier Narrows, Landers, Big Bear, and Northridge earthquakes ( Shakal et al., 1994) were processed by the California Division of Mines and Geology (CDMG). Records of other earthquakes listed in Table 1 were processed by LeAuto software at USC ( Lee and Trifunac, 1990) from xerox copies of original recordings supplied by CDMG. ...
Similar publications
The effect of the sulfate attack on reinforced concrete structures in the Lagos lagoon environment has become a concern for stakeholders in the construction industry. This study investigated the flexural strength and microstructure of reinforced concrete beams for a period of 365 days. Thirty beams with dimension 150 mm × 150 mm × 600 mm were cast...
The article deals with the assessment of reinforced concrete structures of a hazardous production facility, namely, the localizing facility of a nuclear power plant during the construction. The analysis of the methods applicability for determining the strength of concrete for this type of structures.
In reinforced concrete structures, the beam-column connection area has a considerable influence on the behavior of the structure. The use of fiber-reinforced polymer FRP to strengthen the connections in the Reinforced structure can be one of the solutions to transform this area, thus improving the behavior of the structure, which is achieved throug...
The design of reinforced concrete structures strongly depends on the value of the compression concrete strength used for the structural components. Given the uncertainties involved on the materials quality provided by concrete manufacturers, in the construction stage, these components may be either over or under-reinforced respect to the nominal co...
![Figure 2. Standard machine used to test the bamboo tensile strength [22].](publication/325458667/figure/fig1/AS:632150709768200@1527727882775/Standard-machine-used-to-test-the-bamboo-tensile-strength-22_Q320.jpg)
Citations
... Figure 2 depicts the seismic damage in the south frame caused by the Northridge earthquake and shows the location of sensors at the ground, 1st, 2nd, 5th, and 7th floors. (Trifunac and Ivanovic 2003). ...
This paper proposes a high-resolution seismic monitoring framework that employs dissipated energy as a feature for damage detection and localization in instrumented building structures. The methodology consists of (1) implementing a nonlinear state observer to reconstruct the dynamic response at all degrees of freedom (DoF) of a structural model, (2) employing the reconstructed response to estimate element-by-element forces and displacements, and (3) using estimated displacement, forces, and constitutive laws to estimate element-level dissipated energy. The main advantages of the proposed energy-based approach are that i) the proposed feature is physically meaningful and correlates well with the level of cyclic damage experienced during strong earthquakes, ii) dissipated energy can be reconstructed from element-level stress-strain fields that can be estimated from global acceleration measurements, and (iii) dissipated energy can be calibrated using experimental data. The effectiveness of the proposed energy-based seismic monitoring framework is investigated using data from the Van Nuys hotel tested, a seven-story reinforced concrete (RC) building instrumented by the California Strong Motion Instrumentation (CSMIP) Program (Station 24386). The Van Nuys building experienced insignificant structural and mostly nonstructural damage during the 1992 Big Bear earthquake. Two years later, the building was severely damaged during the 1994 Northridge earthquake, in which localized damage occurred in five of the nine columns on the fourth story (between floors four and five) of the south longitudinal frame.
... In this paper, the parameters of our building model are chosen to correspond approximately to the east-west (EW) response of Van Nuys seven-story hotel (VN7SH; Figure 1), an instrumented reinforced concrete building in the Los Angeles Metropolitan Area, which was lightly damaged by the M S = 6.5 San Fernando earthquake of 9 February 1971, and, 23 years later, severely damaged by the M L = 6.4 Northridge earthquake of 17 January 1994 [18][19][20]. As a rare example of an instrumented building that has been severely damaged by an earthquake, it has been the subject of or the motivation for many studies [1,14,16,[21][22][23][24][25][26][27][28][29][30][31]. During the 1994 Northridge earthquake, its response was recorded by a 13-channel CR-1 central recording system and a self-contained triaxial SMA-1 accelerograph with common trigger time [19,32]. ...
... In this paper, the parameters of our build model are chosen to correspond approximately to the east-west (EW) response of V Nuys seven-story hotel (VN7SH; Figure 1), an instrumented reinforced concrete build in the Los Angeles Metropolitan Area, which was lightly damaged by the MS = 6.5 Fernando earthquake of 9 February 1971, and, 23 years later, severely damaged by the = 6.4 Northridge earthquake of 17 January 1994 [18][19][20]. As a rare example of an ins mented building that has been severely damaged by an earthquake, it has been the sub of or the motivation for many studies [1,14,16,[21][22][23][24][25][26][27][28][29][30][31]. During the 1994 Northridge ea quake, its response was recorded by a 13-channel CR-1 central recording system an self-contained triaxial SMA-1 accelerograph with common trigger time [19,32]. ...
Citation: Abbasgholiha, H.; Gičev, V.; Trifunac, M.D.; Jalali, R.S.; Todorovska, M.I. Collapsing Abstract: The sequence of collapsing stages of buildings during strong earthquake shaking is still a poorly understood phenomenon. This study aims to use numerical simulations to improve our understanding of the sequence of phenomena that accompany the collapse of buildings during damaging earthquakes. For that purpose, we use a nonlinear shear-beam model of a building that is excited by a sequence of large horizontal and vertical displacement pulses at its base. The propagation of the input pulses through the structure is simulated by a finite difference scheme. We select the properties of our model to be similar to those of a seven-story hotel in San Fernando Valley of the Los Angeles metropolitan area, which was damaged during the 1994 Northridge, California earthquake. We present results of one example of collapsing response of the model to hypothetical but plausible ground motion close to an earthquake fault. We illustrate the response only for a sequence of horizontal and vertical pulses. We show the differences in the nature of the collapsing sequence for vertical upward and downward pulses of ground motion. Rocking input motions will be added in our future work. Improved understanding of the stages of collapse of buildings will be useful for the development of design strategies to prevent it.
... Rotational seismology is an emerging branch in the field of seismology, including the study of seismic rotations and strains Igel et al., 2012). The recorded data from the previous earthquake shows that the damage to the structure due to earthquake ground motion is not only the effect of translational motion, but rotations and strains also played a significant role (e.g., Hart et al. (1975); Ariman and Hamada (1981); Zerva (1992); Trifunac and Ivanovic (2003); Trifunac (2006); Kalkan and Graizer (2007a, b); Trifunac (2008); Santoyo (2014); Bońkowski et al. (2019). Due to a lack of technological advancement in the past, the direct measurement of earthquake-related rotations and strains made slow progress. ...
The unmatched seismic theoretical rotations from the experimental data led the researchers to develop the reduced micropolar theory in seismology. The study here mainly focuses on the finite-fault simulations for rotations and strains in the near-fault region for a causative strike-slip fault of the Mw\documentclass[12pt]{minimal} \usepackage{amsmath} \usepackage{wasysym} \usepackage{amsfonts} \usepackage{amssymb} \usepackage{amsbsy} \usepackage{mathrsfs} \usepackage{upgreek} \setlength{\oddsidemargin}{-69pt} \begin{document}$$M_w$$\end{document} 6.5 event. Firstly, the parametric investigation is performed on additional material parameters, viz. micropolar couple modulus and microinertia density to the rotations and strains. Secondly, the seismic source parameters such as rupture velocity, slip velocity, burial fault depth, earthquake magnitude, hypocenter location and slip amplitude are varied to see the effect of these parameters on rotations and strains seismograms. The results in different scenarios are compared to the classical elastic medium and reduced micropolar medium. The rotations obtained using reduced micropolar theory are comparatively high to the rotations of classical elastic theory. Although, the obtained displacements in both theories are almost the same. The normal strains in both theories are equivalent, while the shear strains differ as the shear strains in reduced micropolar theory are asymmetric and rotation dependent. The increment in the value of microinertia density increases the rotations, however, the converse is true in the case of micropolar couple modulus. The parametric analysis results demonstrate that near-fault ground rotations and strains are highly sensitive to changes in the seismic source parameters. For instance, modelling the medium homogeneous decreases the amplitude and duration of seismograms sharply compared to layered media. Finally, peak ground contours of displacements, rotations and strains are presented for different hypocenter locations using grid point simulation, and it is found that a change of hypocenter location alters the spatial distribution of peak values of these quantities in the near-fault region of the surface plane. Nevertheless, the maximum limit of peak values over the entire ground surface is near equal for the different hypocentral locations.
... The added stiffness in the exterior frames associated with the spandrel beams creates exterior frames that are roughly twice as stiff as the interior frames. The floor system is a reinforced concrete flat slab that is 25.4-cm thick at the second floor, 21.6-cm thick at the third-to-seventh floors, and 20.3-cm thick at the roof [32][33][34][35][36]. The building is relatively stiff for shear deformations on the lowest two floors and more flexible between the third floor and roof (Figure 3) [24]. ...
We present a simple nonlinear model of a shear-beam building that experiences large nonlinear deformations and collapse when excited by large pulses of strong earthquake ground motion. In this paper, we introduce the model and show that its properties can be selected to be consistent with the damage observed in a seven-story hotel in San Fernando Valley of the Los An-geles metropolitan area during the 1994 Northridge earthquake. We also show an example of exci-tation that leads to the collapse of the model. We illustrate the response only for a sequence of horizontal pulses. We will describe the response of the same model to horizontal, vertical, and rocking motions at its base, as well as for more general excitation by strong earthquake ground motion, in future papers.
Citation:
Abbasgholiha, Hamid, Vlado Gičev, Mihailo D. Trifunac, Reza S. Jalali, and Maria I. Todorovska. 2023. "Collapsing Response of a Nonlinear Shear-Beam Building Model Excited by a Strong-Motion Pulse at Its Base" GeoHazards 4, no. 1: 40-62. https://doi.org/10.3390/geohazards4010004
Early access version available at:
https://www.mdpi.com/2624-795X/4/1/4
... Depending on the building and on the current building codes, either simple methods estimating eccentricity based on the floor width towards a specific direction, or other Probabilistic Seismic Hazard Assessment for the Broader Messinia (SW Greece) Region dynamic spectral methods are applied. According to Trifunac and Ivanovic (2003) and Trifunac (2006), torsion was more intense to the movement of the highest floor at a seven-story building in the 1971 San Fernando earthquake. Both torsion and rocking may affect buildings during earthquake shaking, especially the multi-story ones. ...
Messinia is located in SW Peloponnese (Greece), in the vicinity of the Hellenic Arc which is one of the most seismically active areas of Europe. The arc is dominated by reverse faulting, whereas normal faults are mapped onshore, mainly striking N–S. Large earthquakes have occurred in the study area, both in the historical and instrumental periods. In the present study, a Probabilistic Seismic Hazard Assessment (PSHA) is applied to estimate the Peak Ground Acceleration (PGA), Peak Ground Velocity (PGV), Peak Ground Rotational Acceleration (PGRA) and Peak Ground Rotational Velocity (PGRV) for the broader Messinia region. PGRA and PGRV are not often examined in detail in the literature, even though they are useful for the evaluation of the possible damages in structures. The widely used approach proposed by Cornell and McGuire is implemented taking into account: (a) the seismotectonic model proposed by Seismic Hazard Harmonization in Europe (SHARE), (b) an earthquake catalogue for the instrumental period and (c) Ground Motion Prediction Equations (GMPEs) proposed for the Greek territory. The computational grid spacing for Messinia was set to 1 km, in order to accurately calculate the hazard parameters and to reduce the bias of the results through interpolation processes. For PGA and PGV, a logic tree approach is considered, where every branch is a hybrid version of each GMPE considering the percentage of the type (normal or non-normal) of focal mechanisms for all zones of the seismotectonic model. The results show an increase of the hazard values in the NW part of the study area, where the Greek Building Code provides lower PGA values. In addition, hazard curves in terms of PGA for multiple probabilities of exceedance in 50 years are determined for five major towns of Messinia, i.e. Kalamata, Messini, Filiatra, Kyparissia and Pylos. Kyparissia has the higher hazard in all probabilities of exceedance, which is in full agreement with the PGA and PGV results. Pylos and Filiatra have intermediate to high hazard, whereas Kalamata and Messini show intermediate hazard values. Furthermore, the Uniform Hazard Spectrum (UHS) in terms of Spectral Acceleration for the same towns is computed. The latter provides essential information about the design parameters. Lastly, the results are compared to the seismic histories of the five major towns in terms of European Macroseismic Scale (EMS98) intensity, plotted for the last 200 years.
... Post-earthquake inspection red-tagged the building and revealed that the damage was severe in the south longitudinal frame (Frame A). In Frame A, five of the nine columns in the 4th story (between floors 4 and 5) were heavily damaged due to inadequate transverse reinforcement, and shear cracks ( ≥ 5 cm) and bending of longitudinal reinforcement were easily visible [50]. ...
This paper develops a decision making framework for post-earthquake assessment of instrumented buildings in a manner consistent with performance-based design criteria. This framework is achieved by simultaneously combining and advancing existing knowledge from seismic structural health monitoring and performance-based earthquake engineering paradigms. The framework consists of (1) measurement, (2) uncertainty modeling, (3) dynamic response reconstruction, (4) damage estimation, and (5) performance-based assessment and decision making. In particular, the main objective is to reconstruct inter-story drifts with a probabilistic measure of exceeding performance-based acceptance limits and determine the post-earthquake re-occupancy classification of the instrumented building of interest. Since the proposed framework is probabilistic, the outcome can be used to obtain the probability of losses based on the defined decision variables and be integrated into a risk-based decision making process by city officials, building owners, and emergency managers. The framework is illustrated using data from the Van Nuys hotel testbed, a seven-story reinforced concrete building instrumented by the California Strong Motion Instrumentation Program (CSMIP Station 24386).
... Postearthquake inspection red-tagged the building and revealed that the damage was severe in the south longitudinal frame (Frame A). In Frame A, five of the nine columns on the fourth story (between floors four and five) were heavily damaged due to inadequate transverse reinforcements, and shear cracks (≥5 cm) and bending of the longitudinal reinforcement were easily visible (Trifunac and Ivanovic 2003). Fig. 6 demonstrates the seismic damage following the 1994 Northridge earthquake in the south and north frames. ...
The authors propose a seismic monitoring framework for instrumented buildings that employs dissipated energy as a feature for damage detection and localization. The proposed framework employs a nonlinear model-based state observer that combines a nonlinear finite element model of a building and global acceleration measurements to estimate the time history of the seismic response at all of the model's degrees of freedom. This includes displacements, element forces, and plastic deformations in all structural members. The estimated seismic response is then used to (1) estimate interstory drifts and determine the postearthquake reoccupancy classification of the building based on performance-based criteria, (2) compare the estimated demands with code-based capacity and reconstruct element-by-element demand-to-capacity ratios, and (3) reconstruct element-level normalized energy dissipation and ductility. The outcome of this process is employed for performance-based monitoring, damage detection, and localization in instrumented buildings. The proposed framework is validated using data from the Van Nuys hotel testbed, a seven-story reinforced concrete building instrumented by the California Strong Motion Instrumentation Program (Station 24386). The nonlinear state observer of the building was implemented using a distributed plasticity finite element model and seismic response measurements during the 1992 Big Bear and 1994 Northridge earthquakes. The performance and damage assessment results are compared with the postearthquake damage inspection reports and photographic records. The results demonstrate the accuracy and capability of the proposed framework in the context of a real-world instrumented building that experienced significant localized structural damage.
... Post-earthquake inspection redtagged the building and revealed that the damage was severe in the south longitudinal frame (Frame A). In Frame A, five of the nine columns in the 4th story (between floors 4 and 5) were heavily damaged due to inadequate transverse reinforcement, and shear cracks (≥ 5cm) and bending of longitudinal reinforcement were easily visible [21]. ...
This paper presents a framework for decision-making regarding post-earthquake assessment of instrumented buildings in a manner consistent with performance-based design criteria. This framework is achieved by simultaneously combining and advancing existing knowledge from seismic structural health monitoring and performance-based earthquake engineering paradigms and consists of 1) optimal sensor placement, 2) dynamic response reconstruction, 3) damage estimation, and 4) performance-assessment and decision-making. In particular, the main objective is to reconstruct inter-story drifts with a probabilistic measure of exceeding performance-based acceptance limits and determining the post-earthquake re-occupancy classification of the instrumented building of interest. Since the proposed framework is probabilistic, the outcome can be used to obtain the probability of losses based on the defined decision variables and be integrated into a risk-based decision-making process by city officials, building owners, and emergency managers. The framework is illustrated using data from the Van Nuys hotel testbed, a seven-story reinforced concrete building instrumented by the California Strong Motion Instrumentation Program (Station 24386).
... Post-earthquake inspection red-tagged the building and revealed that the damage was severe in the south longitudinal frame (Frame A). In Frame A, five of the nine columns in the 4th story (between floors 4 and 5) were heavily damaged due to inadequate transverse reinforcement, and shear cracks (≥ 5cm) and bending of longitudinal reinforcement were easily visible (Trifunac and Ivanovic 2003). ...
The authors propose a seismic monitoring framework for instrumented buildings that employs dissipated energy as a feature for damage detection and localization. The proposed framework employs a nonlinear model-based state observer, which combines a nonlinear finite element model of a building and global acceleration measurements to estimate the time history of seismic response at all degrees of freedom of the model. This includes displacements, element forces, and plastic deformations in all structural members. The estimated seismic response is then used to 1) estimate inter-story drifts and determine the post-earthquake re-occupancy classification of the building based on performance-based criteria, 2) compare the estimated demands with code-based capacity and reconstruct element-by-element demand-to-capacity ratios and 3) reconstruct element-level normalized energy dissipation and ductility. The outcome of this process is employed for the performance-based monitoring, damage detection, and localization in instrumented buildings. The proposed framework is validated using data from the Van Nuys hotel testbed; a seven-story reinforced concrete building instrumented by the California Strong Motion Instrumentation Program (Station 24386). The nonlinear state observer of the building is implemented using a distributed plasticity finite element model and seismic response measurements during the 1992 Big Bear and 1994 Northridge earthquakes. The performance and damage assessment results are compared with the post-earthquake damage inspection reports and photographic records. The results demonstrate the accuracy and capability of the proposed framework in the context of a real instrumented building that experienced significant localized structural damage.
... 3-7, 11 and 12 in Table 2) were digitized at the University of Southern California from photo copies in published reports. More information about this building can be found in our papers and reports [16,17,29,31,45,46,[5][6][7]50]. In the long direction of the building, for events after the San Fernando earthquake, two channels recorded the response at the two ends of the building. ...
In the 1960s, Kanai and Yoshizawa proposed a simple formula for computing the response of a building at the base or at an intermediate level from recorded motion at the top (referred to here as KY formula). In that formula, derived based on the ray theory of shear wave propagation in a building, represented as a soft layer, the motion at the base is computed simply as the average of two time shifts of the motion at the roof. In this paper, we tested the goodness of the prediction of displacement response by the KY formula in 54 instrumented buildings in the Los Angeles area for which earthquake records are available both at base and top floor (or roof). The results show close agreement of the predicted and observed displacements for a variety of buildings and amplitudes and spectral content of the motions. It is concluded that the KY method can be a practical tool for extending the usefulness of earthquake records in buildings in which only the roof record is available. It can also be used to predict displacements at any desired level which is useful for estimation of interstory drifts.
