Near-field velocity pulse-like ground motions on February 6, 2018 MW6.4 Hualien, Taiwan earthquake and structural damage implications

ABSTRACT Shaking from the 6 July 2019 Mw 7.1 Ridgecrest, California, mainshock was strongly felt through southern California, but generated relatively minimal structural damage in Ridgecrest. We consider the extent to which a damage proxy map (DPM) generated from satellite-based Synthetic Aperture Radar images can detect minor damage throughout the town of Ridgecrest. The DPM does not, as expected, detect all minor structural damage to individual structures, nor can it distinguish between structural damage and earthquake-related movement that is not consequential. However, the DPM does confirm many instances of minor structural damage to larger structures and groups of smaller structures and in some instances suggests minor structural damage that is not apparent upon visual inspection. Although ambiguous identification of minor damage may not be useful to guide earthquake response, the identification of minor, possibly hidden damage is potentially useful for other purposes. Overall, the DPM confirms that structural damage was commensurate with modified Mercalli intensity no higher than 7 throughout Ridgecrest. We consider both instrumental and intensity data to explore further the distribution of near-field ground motions over the frequency range of engineering concern. Peak ground accelerations and peak ground velocities estimated from “Did You Feel It?” intensity data using the Worden et al. (2012) ground-motion intensity conversion equation (GMICE) are consistent with recorded instrumental data. Both instrumental and estimated mainshock peak accelerations are further consistent with predictions from both the Boore et al. (2014) ground-motion prediction equation (GMPE), but lower than predicted by the Atkinson and Wald (2007) and Atkinson et al. (2014) intensity prediction equations (IPEs). A GMPE such as Boore et al. (2014), which is constrained by a large global dataset, together with a well-constrained GMICE, may thus characterize expected shaking intensities for large earthquakes better than an IPE based on more limited intensity data.

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Fragility Analysis of Gantry Crane Subjected to Near-Field Ground Motions

Applied Sciences ◽

10.3390/app10124219 ◽

2020 ◽

Vol 10 (12) ◽

pp. 4219

Author(s):

Qihui Peng ◽

Wenming Cheng ◽

Hongyu Jia ◽

Peng Guo

Keyword(s):

Failure Probability ◽

Structural Damage ◽

Fragility Curves ◽

Damage Control ◽

Ground Motions ◽

Near Field ◽

Vertical Component ◽

Gantry Crane ◽

Fe Model ◽

Demand Model

A gantry crane located in a near-field earthquake-prone area is selected in this paper as an example, and the nonlinear finite element (FE) model is used considering the material nonlinearity including plastic hinges and the second order (P − Δ ) effect with a comprehensive consideration of the components including sill beams, support beams, legs, and trolley girders. The local displacement ratio (LDR) and deflection ratio (DR) are proposed as demand measures (DMs) of the gantry crane, which are utilized to construct a probabilistic seismic demand model (PSDM). Then, the capacity limit states for the gantry crane are defined in this study by performing pushover analysis (POA), known as serviceability, damage control, and collapse prevention, respectively. Moreover, the operating capacity of the crane during an earthquake is further investigated and quantified by operating seismic peak ground acceleration, which is defined as the maximum acceleration when the failure probability is 50%. Finally, the fragility curves and the failure probability of the gantry crane are derived by the above definitions, all of which are pioneering in the seismic design of gantry cranes subjected to near-field ground motions. Some major conclusions are drawn that the horizontal component of an earthquake has a more notable effect on the structural damage of the gantry crane compared to the vertical component, and incremental dynamic analysis can take seismic uncertainty into account and quantify the deformation of gantry crane in more detail.

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Nonlinear Suppression of High‐Frequency S Waves by the Near‐Field Velocity Pulse With Reference to the 2002 Denali Earthquake

Journal of Geophysical Research Solid Earth ◽

10.1029/2019jb018386 ◽

2020 ◽

Vol 125 (1) ◽

Author(s):

Norman H. Sleep ◽

Tianze Liu

Keyword(s):

High Frequency ◽

Near Field ◽

Velocity Pulse ◽

S Waves ◽

Field Velocity

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Seismic Performance Assessment of Velocity Pulse-Like Ground Motions Under Near-Field Earthquakes

Rock Mechanics and Rock Engineering ◽

10.1007/s00603-021-02475-2 ◽

2021 ◽

Author(s):

Quanbo Luo ◽

Feng Dai ◽

Yi Liu ◽

Mengtan Gao ◽

Zongchao Li ◽

...

Keyword(s):

Performance Assessment ◽

Seismic Performance ◽

Ground Motions ◽

Near Field ◽

Velocity Pulse ◽

Seismic Performance Assessment

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Identification of Near-Field Pulse-Like Ground Motions Recorded at Bajiao Station during the Mainshock of the Great Wenchuan Earthquake

Advanced Materials Research ◽

10.4028/www.scientific.net/amr.250-253.2546 ◽

2011 ◽

Vol 250-253 ◽

pp. 2546-2553 ◽

Cited By ~ 2

Author(s):

Chun Feng Li ◽

Yong Bo Li

Keyword(s):

Wenchuan Earthquake ◽

Ground Motion ◽

Strong Ground Motion ◽

Ground Motions ◽

Near Field ◽

Velocity Pulse ◽

Field Pulse ◽

Near Fault ◽

Ground Motion Records ◽

Strong Ground

When earthquake occurs, it is in near-fault that the most serious damage happens and velocity pulse appears. Velocity pulse could have huge potential to destroy the structure in near-fault. The set of records at Bajiao Station is one of the three famous near-field sets of strong ground motion records whose PGAs are the largest in all the sets of records obtained from the mainshock of the Great Wenchuan Earthquake. Our research is to identify the pulse-like characteristics from the set of records at Bajiao Station. It is found that velocity pulses in the records are “hidden pulses”.

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Shake Table Test of Long Span Cable-Stayed Bridge Subjected to Near-Fault Ground Motions Considering Velocity Pulse Effect and Non-Uniform Excitation

Applied Sciences ◽

10.3390/app10196969 ◽

2020 ◽

Vol 10 (19) ◽

pp. 6969

Author(s):

Chao Zhang ◽

Guanghui Fu ◽

Zhichao Lai ◽

Xiuli Du ◽

Piguang Wang ◽

...

Keyword(s):

Ground Motions ◽

Near Field ◽

Shake Table ◽

Velocity Pulse ◽

Maximum Displacement ◽

Maximum Acceleration ◽

Shake Table Tests ◽

Near Fault ◽

Cable Stayed Bridge ◽

Long Span

This paper presents the results of shake table tests of a scaled long span cable-stayed bridge (CSB). The design principles of the scaled CSB are first introduced. The first six in-plane modes are then identified by the stochastic subspace identification (SSI) method. Furthermore, shake table tests of the CSB subjected to the non-pulse near-field (NNF) and velocity-pulse near-fault (PNF) ground motions are carried out. The tests indicated that: (1) the responses under longitudinal uniform excitation are mainly contributed by antisymmetric modes; (2) the maximum displacement of the tower occurs on the tower top node, the maximum acceleration response of the tower occurs on the middle cross beam, and the maximum bending moment of the tower occurs on the bottom section; (3) the deformation of the tower and girder subjected to uniform excitation is not always larger than that subjected to non-uniform excitation, and therefore the non-uniform case should be considered in the seismic design of CSBs.

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