scholarly journals Impulsive Signals Produced by Earthquakes in Italy and Their Potential Relation with Site Effects and Structural Damage

Geosciences ◽  
2021 ◽  
Vol 11 (6) ◽  
pp. 261
Author(s):  
Deniz Ertuncay ◽  
Petra Malisan ◽  
Giovanni Costa ◽  
Stefano Grimaz
Keyword(s):  
Structural Damage ◽  
Site Effects ◽  
Structural Response ◽  
Time History ◽  
Potential Influence ◽  
Directivity Effect ◽  
Step Effect ◽  
Fling Step ◽  
Seismic Records ◽  
2016 Amatrice Earthquake

Near fault seismic records may contain impulsive motions in velocity-time history. The seismic records can be identified as impulsive and non-impulsive depending on the features that their waveforms have. These motions can be an indicator of directivity or fling step effect, and they may cause dangerous effects on structures; for this reason, there is increasing attention on this subject in the last years. In this study, we collect the major earthquakes in Italy, with a magnitude large or equal to Mw 5.0, and identify the impulsive motions recorded by seismic stations. We correlate impulsive motions with directivity and fling step effects. We find that most earthquakes produced impulsive signals due to the directivity effect, though those at close stations to the 30 October 2016 Amatrice earthquake might be generated by the fling step effect. Starting from the analyzed impulses, we discuss on the potential influence of site effects on impulsive signals and suggest a characterization based on the main displacement directions of the impulsive horizontal displacements. Finally, we discuss on the damage of three churches in Emilia, which were subject to impulsive ground motion, underlying in a qualitative way, how the characteristics of the pulses may have had influences the structural response of the façades.

Nonlinear vibration analysis of a cantilever beam with a breathing crack and bilinear behavior

2021 ◽  
pp. 107754632110183
Author(s):  
Masoud Kharazan ◽  
Saied Irani ◽  
Mohammad Reza Salimi
Keyword(s):  
Cantilever Beam ◽  
Structural Damage ◽  
Crack Depth ◽  
Structural Response ◽  
Time History ◽  
Nonlinear Behavior ◽  
Nonlinear Phenomena ◽  
Breathing Crack ◽  
Cracked Beam ◽  
Practical Engineering

Nonlinear phenomena widely occur in practical engineering applications. A typical example in aerospace structures is the creation of a breathing crack that opens and closes under cyclic loads, which causes bilinear behavior in the structural response. Late detection of such cracks can lead to a catastrophic failure that results in extensive structural damage. Therefore, analyzing the behavior of the structure because of the presence of a breathing crack is very important and needs to be investigated in detail. In this article, the nonlinear response of a single-degree-of-freedom nonlinear cantilever beam with a transverse breathing crack and bilinear behavior was studied. To investigate the nonlinear behavior, bilinear functions of the beam stiffness and nonlinear geometric stiffness were converted to polynomial functions. The proposed model is validated by comparing the time history responses of the approximated polynomials with the bilinear model of the cracked beam. Moreover, by considering damping changes because of the presence of the breathing crack, the nonlinear behavior was investigated. The results indicated that the proposed method is sensitive to the presence of a breathing crack. Also, the nonlinearity increases with an increase in the crack depth and location ratios associated with the jump phenomenon in the vibration response of the cracked beam.

Damage-Involved Structural Pounding in Bridges under Seismic Excitation

2017 ◽  
Vol 754 ◽  
pp. 309-312 ◽  
Author(s):  
Robert Jankowski
Keyword(s):  
Structural Damage ◽  
Structural Model ◽  
Viscoelastic Model ◽  
Time History ◽  
Seismic Wave Propagation ◽  
Seismic Excitation ◽  
Lumped Mass ◽  
Positive Role ◽  
Contact Points ◽  
Elevated Bridge

During severe earthquakes, pounding between adjacent superstructure segments of highway elevated bridges was often observed. It is usually caused by the seismic wave propagation effect and may lead to significant damage. The aim of the present paper is to show the results of the numerical analysis focused on damage-involved pounding between neighbouring decks of an elevated bridge under seismic excitation. The analysis was carried out using a lumped mass structural model with every deck element discretized as a SDOF system. Pounding was simulated by the use of impact elements which become active when contact is detected. The linear viscoelastic model of collision was applied allowing for dissipation of energy due to damage at the contact points of colliding deck elements. The results show that pounding may substantially modify the behaviour of the analysed elevated bridge. It may increase the structural response or play a positive role, and the response depends on pattern of collisions between deck elements. The results also indicate that a number of impacts for a small in-between gap size is large, whereas the value of peak pounding force is low. On the other hand, the pounding force time history for large gap values shows only a few collisions, but the value of peak pounding force is substantially large, what may intensify structural damage.

Application of Earthquake Resistance Analysis Technique in the Design of Constructional Engineering

2013 ◽  
Vol 756-759 ◽  
pp. 4482-4486
Author(s):  
Chun Gan ◽  
Xue Song Luo
Keyword(s):  
Response Spectrum ◽  
Structural Response ◽  
Time History ◽  
Economic Losses ◽  
Element Analysis ◽  
Architectural Engineering ◽  
Analysis Technique ◽  
History Analysis ◽  
Earthquake Resistant ◽  
History Of

In recent years, frequent earthquakes have caused great casualties and economic losses in China. And in the earthquake, damage of buildings and the collapse is the main reason causing casualties. Therefore, in the design of constructional engineering, a seismicity of architectural structure is the pressing task at issue. Through time history analysis method, this paper analyzes the time history of building structural response and then it predicts the peak response of mode by response spectrum analysis. Based on this, this paper constructs a numerical simulation model for the architecture by using finite element analysis software SATWE. At the same time, this paper also calculates the structure seismic so as to determine the design of each function structure in architectural engineering design and then provides reference for the realization of earthquake-resistant building.

Full-Scale Experimental Evaluation of the Flood Resiliency of Thin Concrete Overlay on Asphalt Pavements

2021 ◽  
pp. 036119812110615
Author(s):  
Angel Mateos ◽  
John Harvey ◽  
Miguel Millan ◽  
Rongzong Wu ◽  
Fabian Paniagua ◽  
...  
Keyword(s):  
Structural Damage ◽  
Water Saturation ◽  
Critical Time ◽  
Structural Response ◽  
Extreme Weather Events ◽  
Pavement Materials ◽  
Structural Capacity ◽  
Weather Events ◽  
Pavement Structure ◽  
Falling Weight

The capacity to resist flooding is one of the critical challenges of pavement resiliency in locations subject to inundation. Flooding increases moisture contents, which weakens most pavement materials. Although the effect of moisture on the mechanical properties of most pavement materials is reversible, the structural damage caused by trafficking applied on the weakened pavement structure is not. The critical time for structural damage is typically after the flood and before “life-line” pavements have dried back when trucks are bringing in relief supplies and hauling out demolition. This fact, together with the increased occurrence of extreme weather events and sea level rise resulting from climate change, emphasizes the need to better understand the impacts of flooding on identified life-line pavements. This paper evaluates the flooding resiliency of thin concrete overlay on asphalt (COA) pavements by studying the effects that water saturation produces on the pavement structure. The research is based on the structural response and distresses measured in five thin COA sections that were instrumented with sensors and tested with a heavy vehicle simulator (HVS) under flooded conditions. The research shows that the flooding did not produce a noticeable change in the structural capacity of the COA, based on the structural response measured under the loading of the HVS wheel and the falling weight deflectometer, but did result in some structural damage to the asphalt base in some of the sections.

Nonlinear Structural Damage Detection Based on Adaptive Volterra Filter Model

2018 ◽  
Vol 18 (02) ◽  
pp. 1871003 ◽  
Author(s):  
J. Prawin ◽  
A. Rama Mohan Rao
Keyword(s):  
Damage Detection ◽  
Structural Damage ◽  
Linear Models ◽  
Time History ◽  
Diagnostic Techniques ◽  
Filter Model ◽  
Volterra Filter ◽  
Damage Indices ◽  
Before And After ◽  
Nonlinear Time History

The majority of the existing damage diagnostic techniques are based on linear models. Changes in the state of the dynamics of these models, before and after damage in the structure based on the vibration measurements, are popularly used as damage indicators. However, the system may initially behave linearly and subsequently exhibit nonlinearity due to the incipience of damage. Breathing cracks that exhibit bilinear behavior are one such example of the damage induced due to nonlinearity. Further many real world structures even in their undamaged state are nonlinear. Hence, in this paper, we present a nonlinear damage detection technique based on the adaptive Volterra filter using the nonlinear time history response. Three damage indices based on the adaptive Volterra filter are proposed and their sensitiveness to damage and noise is assessed through two numerically simulated examples. Numerical investigations demonstrate the effectiveness of the adaptive Volterra filter model to detect damage in nonlinear structures even with measurement noise.

scholarly journals Structural Assessment of the Hull Response of an FPSO Unit to Dropped Objects: A Case Study

2019 ◽  
Vol 26 (4) ◽  
pp. 39-46 ◽  
Author(s):  
Ozgur Ozguc
Keyword(s):  
Structural Damage ◽  
Local Buckling ◽  
Structural Response ◽  
Offshore Structures ◽  
Mechanical Equipment ◽  
Structural Members ◽  
Impact Area ◽  
Explicit Dynamic ◽  
The Impact

Abstract Offshore structures are exposed to the risk of damage caused by various types of extreme and accidental events, such as fire, explosion, collision, and dropped objects. These events cause structural damage in the impact area, including yielding of materials, local buckling, and in some cases local failure and penetration. The structural response of an FPSO hull subjected to events involving dropped objects is investigated in this study, and non-linear finite element analyses are carried out using an explicit dynamic code written LS-DYNA software. The scenarios involving dropped objects are based on the impact from the fall of a container and rigid mechanical equipment. Impact analyses of the dropped objects demonstrated that even though some structural members were permanently deformed by drop loads, no failure took place in accordance with the plastic strain criteria, as per NORSOK standards. The findings and insights derived from the present study may be informative in the safe design of floating offshore structures.

scholarly journals The effect of seismic base isolation on structural response of a 12-story hotel building in Padang, Indonesia

2020 ◽  
Vol 156 ◽  
pp. 05026
Author(s):  
Fauzan ◽  
Afdhalul Ihsan ◽  
Mutia Putri Monika ◽  
Zev Al Jauhari
Keyword(s):  
Base Isolation ◽  
Response Spectrum ◽  
Soft Soil ◽  
Structural Response ◽  
Time History ◽  
Seismic Zone ◽  
Isolation System ◽  
Rubber Bearing ◽  
Seismic Base Isolation ◽  
The City

The amount of potential investment in Padang City, Indonesia since 2017 attracted many investors to contribute to the city. One of the investments is a 12-story hotel that will be constructed in By Pass Street of the city. The hotel is located in a high seismic zone area, so the seismic base isolation has been proposed to be used in the hotel building. The main aim of using a seismic base isolation device is to reduce the inertia forces introduced in the structure due to earthquakes by shifting the fundamental period of the structure out of dangerous resonance range and concentration of the deformation demand at the isolation system. An analytical study on the Reinforced Concrete (RC) hotel building with and without rubber bearing (RB) base isolation is carried out using the response spectrum and time history analysis methods. The results show that internal forces and inter-story drift of the building with high damping rubber bearing (HDRB) are lower than that of the fixed base with a remarkable margin. From this study, it is recommended to use the HDRB base isolation for medium and high rise buildings with soft soil in Padang City, Indonesia.

Toward Limit State Design of Ships and Offshore Structures Under Impact Pressure Actions: A State-of-the-Art Review

2006 ◽  
Vol 43 (03) ◽  
pp. 135-145
Author(s):  
Jeom Kee Paik
Keyword(s):  
Limit State ◽  
Structural Response ◽  
Time History ◽  
Rate Sensitivity ◽  
Offshore Structures ◽  
Impact Pressure ◽  
Green Water ◽  
Limit State Design ◽  
Structural Capacity ◽  
Pressure Time

In design of ships and ship-shaped offshore units, issues related to impact pressure actions arising from sloshing, slamming, green water, or explosion are of particular concern. The structural response under impact pressure actions is quite different from that under static or quasistatic actions. It has been recognized that the limit state approach is a more rational basis for structural design and safety assessment where both "demand" (loads) and "capacity" (strength) must be accurately defined. For impact pressure action cases, the demand is associated with hydrodynamics areas, taking into account the characteristics of impact pressure-time history, and the structural capacity is associated with structural mechanics areas, considering geometric and material nonlinearities together with strain rate sensitivity. This paper reviews recent advances and trends toward future limit state design of ships and offshore structures under impact pressure actions.

Influence of Orientation of Seismic Records on Structural Response

2009 ◽  
Vol 96 (12) ◽  
pp. 21-30
Author(s):  
Konstantinos Kostinakis ◽  
Asimina Athanatopoulou ◽  
Ioannis Avramidis
Keyword(s):  
Structural Response ◽  
Seismic Records

Viscoelastic Coupling Dampers for Enhanced Multiple Seismic Hazard Level Performance of High-Rise Buildings

2018 ◽  
Vol 34 (4) ◽  
pp. 1847-1867 ◽  
Author(s):  
Renée MacKay-Lyons ◽  
Constantin Christopoulos ◽  
Michael Montgomery
Keyword(s):  
Seismic Hazard ◽  
Structural Damage ◽  
Time History ◽  
Coupled System ◽  
Nonlinear Time History Analysis ◽  
Coupling Beams ◽  
Restoring Force ◽  
High Rise ◽  
Amplitude Maximum ◽  
Hazard Level

Viscoelastic coupling dampers (VCDs) are installed in lieu of traditional reinforced concrete (RC) coupling beams in high-rise buildings to provide distributed supplemental damping for all dynamic loading conditions without affecting the architectural layout. When distributed effectively over the height of the building, VCDs provide viscous damping in all lateral modes of vibration and an elastic restoring force that enhances the lateral stiffness of the coupled system. In this paper, a first extensive numerical case study is carried out to compare the seismic performance of a conventional coupled shear wall high-rise building to a high damping alternate of the same design in which VCDs replace all diagonal RC beams in the core to enhance its seismic resilience. The added damping from VCDs is intended to reduce the peak responses under low amplitude earthquakes, but for larger amplitude maximum credible earthquakes, the peak responses are similar; however, structural damage is greatly reduced. Three seismic hazard levels were investigated, and the results indicate that the use of VCDs reduces peak floor accelerations, story drifts, and story shears over all seismic intensities. Nonlinear time-history analysis results also highlighted the improved resilience of the VCD structure at the maximum credible seismic hazard level where the use of VCDs eliminated all damage to coupling beams that would otherwise require repair over most of the height of the building.

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