Optimal intensity measures for probabilistic seismic demand modeling of extended pile-shaft-supported bridges in liquefied and laterally spreading ground

Wang, Xiaowei; Shafieezadeh, Abdollah; Ye, Aijun

doi:10.1007/s10518-017-0199-2

Cited by 134 publications

(46 citation statements)

References 69 publications

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“…Table 3 summarizes the test protocol. 52,53 As seen from top to bottom for the intensity measures in Table 3, they generally increase following the test protocol, indicating that the degree of liquefaction (i.e., soil softening or increments in pore pressures) tends to be gradually aggravated. For the liquefiable scenario, sufficient interval durations between excitations were applied to ensure complete dissipations of excess pore water pressures.…”

Section: Ground Motions and Test Protocolmentioning

confidence: 90%

“…These intensity measures can predict soil liquefaction and associated structural demands. 52,53 As seen from top to bottom for the intensity measures in Table 3, they generally increase following the test protocol, indicating that the degree of liquefaction (i.e., soil softening or increments in pore pressures) tends to be gradually aggravated.…”

Section: Ground Motions and Test Protocolmentioning

confidence: 90%

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Shake‐table investigation of scoured RC pile‐group‐supported bridges in liquefiable and nonliquefiable soils

Wang

Shang

2019

Earthq Engng Struct Dyn

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Summary This paper presents results of one‐g shake‐table tests on scoured pile‐group‐supported bridge models in saturated (liquefiable) and dry (nonliquefiable) sands. The primary objective is to reveal the influence of liquefaction on seismic demands and failure mechanism of scoured bridges. To this end, two identical models, each consisting of a 2 × 2 reinforced concrete pile‐group with a center‐to‐center spacing of 3 times pile diameter, a cap and a single pier with a lumped iron block, were constructed and embedded into saturated and dry sands, respectively, with the same scour depth of 4 times pile diameter. Typical test results, including excess pore pressure, acceleration and displacement demands are interpreted first, followed by the focus on curvature demands and associated seismic failure mechanism identification. Finally, inertial and kinematic effects on pile curvature demands are estimated using cross‐correlation analyses. Results show that near‐pile liquefied soils exhibit more remarkable dilation tendency as compared to far field. For bridges under the given scour depth, soil liquefaction tends to significantly affect the failure modes via transferring damage positions from pier bottom to pile head and meanwhile from underground pile to pile head. In addition, pile group effects appear to be significant in nonliquefiable soils while to be relatively inessential in liquefied soils. Moreover, the inertial effect is more prominent in nonliquefiable soils, while the kinematic effect itself generally appears to be more significant in liquefiable soils. The test results can be used to validate numerical models for future studies.

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Section: Ground Motions and Test Protocolmentioning

confidence: 90%

Section: Ground Motions and Test Protocolmentioning

confidence: 90%

Shake‐table investigation of scoured RC pile‐group‐supported bridges in liquefiable and nonliquefiable soils

Wang

Shang

2019

Earthq Engng Struct Dyn

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“…Figure 3b-3e shows the distribution of PGA, peak ground velocity, modified cumulative absolute velocity, and Housner spectrum intensity. The reason to plot these distributions is that these IMs are found to be highly correlated with seismic responses of extended pile-shaft-supported bridges in laterally spreading ground (Wang et al 2018). From these plots, it is clear that the selected 170 ground motions cover a wide range of intensities that can trigger full seismic behaviors of the bridge models, from elastic to plastic and even collapse.…”

Section: Ground Motions Simulation Algorithms and Indicative Seismic Responsesmentioning

confidence: 99%

Optimal EDPs for Post-Earthquake Damage Assessment of Extended Pile-Shaft–Supported Bridges Subjected to Transverse Spreading

Wang

Shafieezadeh

2019

Earthquake Spectra

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During earthquakes, extended pile-shaft–supported bridges in laterally spreading ground can undergo inelastic deformations, especially in their embedded portions. Following earthquakes, it is critical to assess damage to these difficult-to-inspect portions and determine whether vehicles can safely pass bridges. This paper aims to identify optimal aboveground engineering demand parameters (EDPs) that are readily measurable after earthquakes and have high-quality probabilistic associations with post-earthquake load-carrying capacity of bridges as well as underground difficult-to-inspect EDPs. For this purpose, an experimentally validated bridge-soil-foundation model considering liquefaction-induced lateral spreading is adopted and subjected to ground-motion time histories in the transverse direction. Subsequently, pushdown analyses are performed to assess the post-earthquake vertical load-carrying capacity of bridges. Metrics such as efficiency, practicality, and measurability are established and examined for EDPs. Results show that residual column drift ratio is the optimal EDP for load-carrying capacity assessments, whereas maximum column drift ratio best predicts pile demands. Furthermore, developed probabilistic relationships between residual and maximum column drift ratios will assist in preliminary post-earthquake evaluation of bridges for damage assessment and posting decisions.

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“…However, for a fast screening of various candidates IM s, the RMS can be approximated for a suite of real ground motion records in order to provide a preliminary ranking of candidate IM s with respect to a prescribed reference IM 37,38 . Recently, many research efforts have employed the RSM for evaluating the relative sufficiency among different IM s (e.g., 19,25,39–42 ). It is worth mentioning that the calculation of RSM was originally carried out 37,38 by employing the CA and the underlying probabilistic model for the linear logarithmic regression.…”

Section: Introductionmentioning

confidence: 99%

Selection of seismic intensity measures for prescribed limit states using alternative nonlinear dynamic analysis methods

Ebrahimian

Jalayer

2020

Earthq Engng Struct Dyn

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In performance‐based earthquake engineering, the suitability of an intensity measure (IM) is expressed through its efficiency and sufficiency. An efficient IM leads to a small record‐to‐record variability in the estimation of demand given seismic intensity. A sufficient IM is one that renders the estimation of demand for all intensity levels independent of all other ground motion parameters. Given that establishing sufficiency is not a trivial task, the relative sufficiency measure (RSM) has been proposed previously based on information theory concepts. RSM can be employed for quantifying the relative sufficiency of an IM with respect to another IM by the amount of extra information that it relays on average about the ground motion for the estimation of a demand parameter of interest. RSM has been so far conditioned on a linear logarithmic regression probability model, better known as the Cloud Analysis (CA), which relies on unscaled ground‐motion records. This work lays out the methodology for estimating both the efficiency and RSM in terms of the damage measure directly (instead of demand parameter) and by employing alternative nonlinear dynamic analysis procedures (NDAPs), such as, a modified version of CA that considers the collapse‐cases explicitly and the incremental dynamic analysis. It is demonstrated that the RSM can be sensitive to the NDAP employed, while it does not demonstrate significant sensitivity to the limit state of interest. An alternative measure of efficiency (known in literature as proficiency), directly measured as the dispersion in the fragility curve, shows more sensitivity to the limit state.

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Optimal intensity measures for probabilistic seismic demand modeling of extended pile-shaft-supported bridges in liquefied and laterally spreading ground

Cited by 134 publications

References 69 publications

Shake‐table investigation of scoured RC pile‐group‐supported bridges in liquefiable and nonliquefiable soils

Shake‐table investigation of scoured RC pile‐group‐supported bridges in liquefiable and nonliquefiable soils

Optimal EDPs for Post-Earthquake Damage Assessment of Extended Pile-Shaft–Supported Bridges Subjected to Transverse Spreading

Selection of seismic intensity measures for prescribed limit states using alternative nonlinear dynamic analysis methods

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