Seismic fragility assessment of multi-span concrete highway bridges in British Columbia considering soil–structure interaction

2021 ◽  
Vol 48 (1) ◽  
pp. 39-51 ◽  
Author(s):  
A.H.M. Muntasir Billah ◽  
M. Shahria Alam

Fragility curve is an effective tool for identifying the potential seismic risk and consequences during and after an earthquake. Recent seismic events have shown that bridges are highly sensitive and vulnerable during earthquakes. There has been limited research to evaluate the seismic vulnerability of the existing bridges in British Columbia (BC), which could help in the decision-making process for seismic upgrade. This study focuses on developing seismic fragility curves for typical multi-span continuous concrete girder bridges in BC. Ground motions compatible with the seismic hazard were used as input excitations for vulnerability assessment. Uncertainties in material and geometric properties were considered to represent the bridges with similar structural characteristics and construction period. The fragility of the bridge is largely attributable to the fragilities of the columns, and to a lesser extent, the abutment and bearing components. The results of this study show that, although not very significant, the soil–structure interaction has some effect on the component fragility where this effect is not very significant at the bridge system level.

2021 ◽  
Author(s):  
Davide Forcellini ◽  
Daniele Mina ◽  
Hassan Karampour

Abstract Soil structure interaction (SSI) may considerably affect the seismic vulnerability of subsea high pressure/high temperature (HP/HT) pipelines. Numerical simulations are herein proposed to study the effects of soil deformability on failure of an unburied pipeline with D/t = 20, laid on the seabed and resting on a sleeper. OpenSees is used to assess an earthquake scenario imposed on a laterally buckled pipeline by considering the effects of non-linear soil behaviour on the mechanisms that induce damage on the soil-pipeline system. Uncertainties in the case study were considered by applying a probabilistic-based approach and by developing analytical fragility curves that allow estimation of the probability of exceedance of the selected failure criteria.


2020 ◽  
Vol 16 (1) ◽  
pp. 39-48
Author(s):  
Parham Bakhtiari ◽  
Khosro Bargi

AbstractThe assessment of the seismic behavior of the high-speed railway bridges is necessary because of the strategic essence of these structures. Evaluating and predicting damages of the bridges that originated by earthquakes with various intensities can provide useful information, which is very helpful in the management of the possible crises. One of the most useful mechanisms for estimating earthquake damages to these bridges is the development of fragility curves for them. Studies on the production of fragility curves on the high-speed railway bridges are limited. In this research, the fragility curve is plotted for two high-speed railway bridges with different pier heights. Due to the differences in the height of these bridges, a comparison of the performance of these structures is also shown. The model of the high-speed railway bridge was created for each model separately in the SeismoStruct software. The soil-structure interaction is also modeled as springs, and its effects are considered. Nonlinear models are also used to model concrete and steel materials. Then, the incremental dynamic analysis was performed under different ground motion records. By using the obtained data from the analysis, appropriate damage states were selected, and finally, the fragility curves were plotted for different performance limit states. The results showed that with increasing pier height, the damage index was raised and for a constant probability of exceedance, the taller pier is demanded a lower spectral acceleration to achieve a performance level.


2019 ◽  
Vol 2019 ◽  
pp. 1-13
Author(s):  
Panpan Zhai ◽  
Peng Zhao ◽  
Yang Lu ◽  
Chenying Ye ◽  
Feng Xiong

Most conventional seismic fragility analyses of RC buildings usually ignore or greatly simplify the soil-structure interaction (SSI), and the maximum interstory drift ratio (MIDR) is often adopted to establish seismic fragility curves. In this work, an eight-story RC building was designed to study the influence of the SSI on the seismic fragility of RC buildings. Three double-parameter damage models (DPDMs) were considered for the fragility assessment: the Park–Ang model, the Niu model, and the Lu–Wang model. Results show that considering SSI induces a higher fragility than that of the fixed model and that employing the DPDMs for the fragility analysis provides more reasonable results than those evaluated using the MIDR damage index.


Author(s):  
Samer El-Bahey ◽  
Yasser Alzeni ◽  
Konstantinos Oikonomou

Recently, the nuclear industry has made a tremendous effort to assess the safety of nuclear power plants (NPP), as advances in seismology have led to the perception that the potential earthquake hazard in the U.S. may be higher than originally assumed. Due to the conservatism in the NPP design, structures and safety-related items are capable of withstanding earthquakes larger than the safe shutdown earthquake (SSE). One major aspect of conservatism in the design is ignoring the effect of soil-structure interaction (SSI), which results in conservative estimates of seismic demands for plant equipment. In this paper, a typical reactor building (RB) is chosen for a case study to investigate the potential benefit of accounting for SSI effects. A lumped mass stick model is first developed and analyzed with a fixed base configuration, using the free-field ground motion as input at the foundation level, as well as with a SSI configuration. Fragility analyses are then performed for the RB and one of its components to quantify the effects of the SSI on the overall seismic risk. In each case, a family of seismic fragility curves is developed. It is found that consideration of SSI effects in the analysis can improve the component fragilities, and potentially enhance the core damage frequency (CDF) of the plant.


2022 ◽  
Vol 10 (1) ◽  
pp. 110
Author(s):  
Davide Forcellini ◽  
Daniele Mina ◽  
Hassan Karampour

Subsea high pressure/high temperature (HP/HT) pipelines may be significantly affected by the effects of soil structure interaction (SSI) when subjected to earthquakes. Numerical simulations are herein applied to assess the role of soil deformability on the seismic vulnerability of an unburied pipeline. Overcoming most of the contributions existing in the literature, this paper proposes a comprehensive 3D model of the system (soil + pipeline) by performing OpenSees that allows the representation of non-linear mechanisms of the soil and may realistically assess the induced damage caused by the mutual interaction of buckling and seismic loads. Analytical fragility curves are herein derived to evaluate the role of soil structure interaction in the assessment of the vulnerability of a benchmark HP/HT unburied subsea pipeline. The probability of exceeding selected limit states was based on the definition of credited failure criteria.


Buildings ◽  
2022 ◽  
Vol 12 (1) ◽  
pp. 72
Author(s):  
Rabindra Adhikari ◽  
Rajesh Rupakhety ◽  
Prajwal Giri ◽  
Rewati Baruwal ◽  
Ramesh Subedi ◽  
...  

Most of the reinforced concrete buildings in Nepal are low-rise construction, as this type of construction is the most dominant structural form adopted to construct residential buildings in urban and semi-urban neighborhoods throughout the country. The low-rise residential constructions generally follow the guidelines recommended by the Nepal Building Code, especially the mandatory rules of thumb. Although low-rise buildings have brick infills and are randomly constructed, infill walls and soil–structure interaction effects are generally neglected in the design and assessment of such structures. To this end, bare frame models that are used to represent such structures are questionable, especially when seismic vulnerability analysis is concerned. To fulfil this gap, we performed seismic vulnerability analysis of low-rise residential RC buildings considering infill walls and soil–structure interaction effects. Considering four analysis cases, we outline comparative seismic vulnerability for various analysis cases in terms of fragility functions. The sum of observations highlights that the effects of infills, and soil–structure interaction are damage state sensitive for low-rise RC buildings. Meanwhile, the design considerations will be significantly affected since some performance parameters are more sensitive than the overall fragility. We also observed that the analytical fragility models fundamentally overestimate the actual seismic fragility in the case of low-rise RC buildings.


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