scholarly journals Seismic Damage Model of Bridge Piers Subjected to Biaxial Loading Considering the Impact of Energy Dissipation

2019 ◽  
Vol 9 (7) ◽  
pp. 1481 ◽  
Author(s):  
Shangshun Lin ◽  
Zhanghua Xia ◽  
Jian Xia

The large degradation of the mechanical performance of hollow reinforced concrete (RC) bridge piers subjected to multi-dimensional earthquakes has not been thoroughly assessed. This paper aims to improve the existing seismic damage model to assess the seismic properties of tall, hollow RC piers subjected to pseudo-static, biaxial loading. Cyclic bilateral loading tests on fourteen 1/14-scale pier specimens with different slenderness ratios, axial load ratios, and transverse reinforcement ratios were carried out to investigate the damage propagation and the cumulative dissipated energy with displacement loads. By considering the influence of energy dissipation on structural damage, a new damage model (M-Usami model) was developed to assess the damage characteristics of hollow RC piers. The results present four consecutive damage stages during the loading process: (a) cracking on concrete surface, (b) yielding of longitudinal reinforcements; (c) spalling of concrete, and (d) collapsing of pier after the concrete crushed and the longitudinal bars ruptured due to the flexural failure. The damage level caused by the seismic waves can be reduced by designing specimens with a good seismic energy dissipation capacity. The theoretical damage index values calculated by the M-Usami model agreed well with the experimental observations. The developed M-Usami model can provide insights into the approaches to assessing the seismic damage of hollow RC piers subjected to bilateral seismic excitations.

2016 ◽  
Vol 16 (11) ◽  
pp. 2357-2371 ◽  
Author(s):  
Patric Kellermann ◽  
Christine Schönberger ◽  
Annegret H. Thieken

Abstract. Experience has shown that river floods can significantly hamper the reliability of railway networks and cause extensive structural damage and disruption. As a result, the national railway operator in Austria had to cope with financial losses of more than EUR 100 million due to flooding in recent years. Comprehensive information on potential flood risk hot spots as well as on expected flood damage in Austria is therefore needed for strategic flood risk management. In view of this, the flood damage model RAIL (RAilway Infrastructure Loss) was applied to estimate (1) the expected structural flood damage and (2) the resulting repair costs of railway infrastructure due to a 30-, 100- and 300-year flood in the Austrian Mur River catchment. The results were then used to calculate the expected annual damage of the railway subnetwork and subsequently analysed in terms of their sensitivity to key model assumptions. Additionally, the impact of risk aversion on the estimates was investigated, and the overall results were briefly discussed against the background of climate change and possibly resulting changes in flood risk. The findings indicate that the RAIL model is capable of supporting decision-making in risk management by providing comprehensive risk information on the catchment level. It is furthermore demonstrated that an increased risk aversion of the railway operator has a marked influence on flood damage estimates for the study area and, hence, should be considered with regard to the development of risk management strategies.


2020 ◽  
pp. 875529302094417
Author(s):  
Siqi Li ◽  
Yongsheng Chen ◽  
Tianlai Yu

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.


Author(s):  
Ragnar T. Igland ◽  
Hagbart S. Alsos ◽  
Stig Olav Kvarme

The safety of pipelines and subsea structures are key elements in subsea field developments. As part of the safety engineering, protection from dropped objects and third party impact actions is required. This article addresses this aspect. Dropped object from a platform or a vessel is one of the design scenarios. The fall-pattern of the object is essential for the impact velocity and corresponding energy, model of the path and the effects of hydrodynamic behavior is outlined. In lieu of accurate information, the design code use energy band for energy estimates and may give extremely conservative impact energy. The falling objects structural flexibility and properties are discussed and evaluated regarding the energy dissipation and possible damage of the pipeline. The pipeline combined response from global deflection and denting regarding impacts are investigated. Analysis and testing methods applied in pipeline design are presented. Focus is placed on the overall interaction between the impacting object, the deformed pipeline and energy dissipation by coating and soil. Typically, pipeline damage from design codes provides conservative cross sectional damage estimates. This is confirmed from both simplified and detailed FE analyses, as well as fullscale impact experiments performed by REINERTSEN AS. One of the main objectives promoted by the authors is the importance of both impact velocity and mass during impact, and not only the kinetic energy of the impact. The kinetic energy from a dropped object is unlikely to be fully dissipated as cross sectional deformation of the pipeline. Global deformations will be triggered, which implies that the dissipated energy going into local denting is reduced to a fractional value. The effect is more pronounced for small diameter pipelines than for pipelines with large diameter. This paper discusses the impact mechanics and seeks to estimate the fractional value by using simplified element analysis.


2009 ◽  
Vol 417-418 ◽  
pp. 925-928
Author(s):  
Shan Suo Zheng ◽  
Liang Zhang ◽  
Bin Wang ◽  
Lei Li ◽  
Lei Zeng

The seismic performance and seismic damage model for steel reinforced high strength and high performance concrete (SRHSHPC) composite frame columns subjected to constant axial load and cyclically variety flexural loading was investigated experimentally. The main influencing parameters, including shear span ratio, axial compression ratio, stirrup ratio and concrete strength, on the seismic performance and seismic damage of the SRHSHPC frame columns is studied. From the test results, the failure mechanism is analyzed and damage quantization criterion is obtained. Several existing seismic damage models are comparatively analyzed. And then, the variation history of accumulated hysteretic energy of the specimens under different loading cycle indexes is figured out, and influence of different test parameters on it is also discussed. Finally, the damage index of the SRHSHPC columns is compared to the existing seismic damage models, and the double variables seismic damage model adapted for the SRHSHPC structure is established by statistical regression theory. The rule of damage evolvement for the specimens is proposed employing variation history of the damage index under different loading cycle indexes. The analytical results indicate that the seismic performance of the SRHSHPC composite column is good, and the double variables damage model could give a quantitative description for damaging process of the samples, which is a reference for seismic damage design of the SRHSHPC structure.


Author(s):  
Patric Kellermann ◽  
Christine Schönberger ◽  
Annegret H. Thieken

Abstract. Experience has shown that river floods can significantly hamper the reliability of railway networks and cause extensive structural damage and disruption. As a result, the national railway operator in Austria had to cope with financial losses of more than one hundred million euros due to flooding in recent years. Comprehensive information on potential flood risk hot spots as well as on expected flood damage in Austria is therefore needed for strategic flood risk management. In view of this, the flood damage model RAIL (RAilway Infrastructure Loss) was applied to estimate 1) the expected structural flood damage, and 2) the resulting repair costs of railway infrastructure due to a 30-year, 100-year and 300-year flood in the Austrian Mur River catchment. The results were then used to calculate the expected annual damage of the railway subnetwork and subsequently analysed in terms of their sensitivity to key model assumptions. Additionally, the impact of risk aversion on the estimates was investigated, and the overall results were briefly discussed against the background of climate change and possibly resulting changes in flood risk. The findings indicate that the RAIL model is capable of supporting decision-making in risk management by providing comprehensive risk information on the catchment level. It is furthermore demonstrated that an increased risk aversion of the railway operator has a marked influence on flood damage estimates for the study area and, hence, should be considered with regard to the development of risk management strategies.


2008 ◽  
Vol 385-387 ◽  
pp. 145-148
Author(s):  
Shan Suo Zheng ◽  
Liang Zhang ◽  
Lei Li ◽  
Bin Wang ◽  
Ming Xie

Based on experimental investigation under low cyclic reversed loading, the seismic behaviors and seismic damage model for steel reinforced high strength and high performance concrete (SRHSHPC) composite frame columns are studied. Several existing seismic damage models are firstly presented and their characteristics are comparatively analyzed. From the test results of low cyclic reversed loading, the variation history of cumulative dissipated hysteretic energy of the SRHSHPC composite frame columns under different loading cycle levels is figured out, and the influence of axial compression ratio, shear span ratio, stirrup ratio and concrete strength on the cumulative dissipated hysteretic energy is also discussed. The damage index of the SRHSHPC composite frame columns is compared according to the existing seismic damage models, and the seismic damage model adapted for the SRHSHPC composite frame columns is established. According to the variation history of the damage index under different loading cycle levels, the rule of damage development for the SRHSHPC composite frame columns is proposed. The influence of axial compression ratio, shear span ratio, stirrup ratio and concrete strength on the damage development is also discussed. The results indicate that the seismic behaviors of the SRHSHPC composite frame column are outstanding, and the seismic damage model could give a quantitative description for damaging process of the samples, which is reference for establishing more rational damage criteria for the SRHSHPC earthquake-resistant composite structure.


Materials ◽  
2021 ◽  
Vol 14 (21) ◽  
pp. 6494
Author(s):  
Mingfei Li ◽  
Mingtao Wu ◽  
Nan Guo ◽  
Lidan Mei ◽  
Yan Zhao

An anchorage device is an integral part of the prestressed Glulam beams. Therefore, its rationality and practicability have significant effects on the mechanical performance of the prestressed beams. To investigate the impact of the anchorage devices on the bearing capacity and stiffness of the prestressed beams, this paper compared and analyzed four kinds of anchors in detail through the finite element software. The results showed that when the initial mid-span deflection was 5 mm, 10 mm, and 15 mm, the bearing capacity of prestressed beams with four anchorage devices was 80.37–177.24%, 93.56–182.51%, and 95.62–194.60% higher than that of ordinary Glulam beam, respectively. When the initial mid-span top prestresses were 1 MPa, 1.5 MPa, and 2 MPa, the bearing capacity of prestressed beams with four anchorage devices was 101.71–172.57%, 105.85–175.88%, and 109.64–180.87% higher than that of ordinary Glulam beam, respectively. In addition, based on the simulation results, the prestressed beam with the external anchorage had the highest bearing capacity and stiffness. The deformation capacity of the beam with boot anchorage was the largest. The stress distribution of the beam installed under beam anchorage was the most uniform, and the beam with slotted anchorage was easy to cause stress concentration at the notch. Finally, based on the outstanding performance of the external anchorage, it was selected to carry out one experiment, and the experimental result showed that the simulation could predict the damage model and load–deflection relationship of the prestressed beams well.


2011 ◽  
Vol 243-249 ◽  
pp. 1508-1511
Author(s):  
Yu Li ◽  
Xi Zhu ◽  
Qing Shan Yang

Reasonable strong seismic motion records are selected according to the applicable Code of Seismic Design for Railway Engineering. By using FEA software, the FEA model of one double-column pier of passenger dedicated line is established with considering the effect of flexible base effects and seismic characteristic. Based on Park-Ang seismic damage model and nonlinear seismic response analysis, the seismic damage analysis on double-column pier of passenger dedicated Line is carried out. The study results are obtained as follow: 1) The seismic damage of bridge mainly happen during the early and middle stage of seismic motion. 2) There are still major discrepancies in the seismic damage made from the seismic records which come from the same site condition and have the same PGA. 3) Although PGA has a great effect on the seismic damage index, it has nothing to do with the happening time of max seismic damage index.


2019 ◽  
Vol 2019 ◽  
pp. 1-7
Author(s):  
Guoliang Yang ◽  
Jingjiu Bi ◽  
Linian Ma

Studying the relationship between energy consumption and crushed size of shale under different loading conditions is the key to efficient shale cracking. The split Hopkinson pressure bar system was used to study the dynamic mechanical properties of shale under parallel- and vertical-bedding loading, and energy dissipation in the impact tests was calculated. Relationships between the average crushed size of shale fracture products and energy dissipation and between the fractal dimension and dissipated energy were studied using fractal theory. The experimental results showed that the dynamic compressive strength of shale under parallel- and vertical-bedding conditions had an obvious positive correlation with the strain rate. Dissipative energy of the shale samples under loading in both directions increased with the increase of strain rate. The increase of the strain rate enhanced crushing of the sample. The vertical-bedding shale samples had stronger ability to absorb energy and more internal crack propagation. Dissipative energies of the shale samples in the parallel- and vertical-bedding impact tests were positively related to the fractal dimension. The fractal dimension increased with the increase of dissipative energy during sample failure; with further increase in the dissipative energy, its effect on the change of fractal dimension gradually weakened.


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