Numerical assessment of vertical ground motion effects on highway bridges

Field evidence of recent earthquakes shows serious bridge damages due to the direct compression or tension in the columns and some flexural and shear failures caused by the variation in axial force of the columns. These damages could not be produced solely by the horizontal seismic excitations; the vertical component of the earthquake is involved. This paper presents a numerical study highlighting the presence of vertical seismic excitation. Nonlinear time history analyses are conducted on detailed three-dimensional models of multi-span simply supported and multi-span continuous bridges using a suite of representative ground motions. The results showed the significant influence of vertical excitation on the bridge responses. Therefore, it is imperative to include more efficient criteria to upgrade the design codes and extend practical techniques that consider and cope with the structural effects of vertical ground motion along with the horizontal excitations.

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Seismic Performance of Reinforced Concrete Bridge Including Effect of Vertical Motion

Applied Mechanics and Materials ◽

10.4028/www.scientific.net/amm.744-746.898 ◽

2015 ◽

Vol 744-746 ◽

pp. 898-904

Author(s):

Hao Lin ◽

Yu Song

Keyword(s):

Reinforced Concrete ◽

Ground Motion ◽

Seismic Performance ◽

Time History ◽

Vertical Motion ◽

Internal Force ◽

Seismic Engineering ◽

Vertical Ground Motion ◽

Field Evidence ◽

Vertical Ground

In recent research of seismic engineering, the damage of bridge due to vertical motion aroused wide concern. Field evidence, experimental results and numerical simulation analysis suggested that vertical ground motion can significantly impact the seismic performance of reinforced concrete (RC) bridge. In this paper, firstly, a FEM model of a continuous rigid frame bridge in China was established . Then the bridge was analyzed using time-history analysis under strong earthquake . Internal force excluding and including vertical motion are compared.Then, the incremental dynamic analysis (IDA) and fiber model are used to calculated the vertical displacement of the node in the top of pier and the sectional curvature of pier. Computational results show that vertical ground motion can increase the internal force and displacement ,as well as reduce the ductility and moment capacity of piers. It is concluded that vertical motion can't be ignored in structure design.

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Vector-Valued Probabilistic Seismic Hazard Assessment for the Effects of Vertical Ground Motions on the Seismic Response of Highway Bridges

Earthquake Spectra ◽

10.1193/1.3464548 ◽

2010 ◽

Vol 26 (4) ◽

pp. 999-1016 ◽

Cited By ~ 25

Author(s):

Zeynep Gülerce ◽

Norman A. Abrahamson

Keyword(s):

Seismic Hazard ◽

Seismic Response ◽

Ground Motion ◽

Ground Motions ◽

Vertical Component ◽

Highway Bridges ◽

Probabilistic Seismic Hazard ◽

Vertical Ground Motion ◽

Vertical Ground Motions ◽

Vertical Ground

The vertical ground motion component is disregarded in the design of ordinary highway bridges in California, except for the bridges located in high seismic zones (sites with design horizontal peak ground acceleration greater than 0.6 g). The influence of vertical ground motion on the seismic response of single-bent, two-span highway bridges designed according to Caltrans Seismic Design Code (SDC-2006) is evaluated. A probabilistic seismic hazard framework is used to address the probability of exceeding the elastic capacity for various structural parameters when the vertical component is included. Negative mid-span moment demand is found to be the structural parameter that is most sensitive to vertical accelerations.A series of hazard curves for negative mid-span moment are developed for a suite of sites in Northern California. The annual probability of exceeding the elastic capacity of the negative mid-span moment is as large as 0.01 for the sites close to active faults when the vertical component is included. Simplified approaches based on the distance to major faults or the median design peak acceleration show that there is a large chance (0.4 to 0.65) of exceeding the elastic limit if the current 0.6 g threshold is used for the consideration of vertical ground motions for ordinary highway bridges. The results of this study provide the technical basis for consideration of a revision of the 0.6 g threshold.

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Seismic demand models for probabilistic risk analysis of near fault vertical ground motion effects on ordinary highway bridges

Earthquake Engineering & Structural Dynamics ◽

10.1002/eqe.1123 ◽

2011 ◽

Vol 41 (2) ◽

pp. 159-175 ◽

Cited By ~ 17

Author(s):

Zeynep Gulerce ◽

Emrah Erduran ◽

Sashi K. Kunnath ◽

Norman A. Abrahamson

Keyword(s):

Risk Analysis ◽

Ground Motion ◽

Highway Bridges ◽

Seismic Demand ◽

Probabilistic Risk Analysis ◽

Near Fault ◽

Vertical Ground Motion ◽

Demand Models ◽

Vertical Ground ◽

Probabilistic Risk

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A superelastic protective technique for mitigating the effects of vertical and horizontal seismic excitations on highway bridges

Journal of Intelligent Material Systems and Structures ◽

10.1177/1045389x16672593 ◽

2016 ◽

Vol 28 (12) ◽

pp. 1533-1552 ◽

Cited By ~ 12

Author(s):

Hadi Aryan ◽

Mehdi Ghassemieh

Keyword(s):

Three Dimensional ◽

Vertical Component ◽

Time History ◽

Highway Bridges ◽

Three Dimensional Model ◽

Seismic Excitations ◽

Innovative System ◽

Bridge Responses ◽

Nonlinear Time History ◽

New System

Vertical component of seismic excitations tremendously affects the performance of bridges during the earthquakes. Several conducted studies identified the lack of engineering attention to the vertical seismic excitation as the main reason of various considerable bridge damages during the past earthquakes. Thus, in this article, an innovative system with superelastic properties is proposed for retrofitting and also new design of the bridges which can simultaneously mitigate the effects of vertical and horizontal seismic excitations. In order to investigate the efficiency of the new system, an evaluation is performed through many nonlinear time history analyses on a three-dimensional model of a detailed multi-span simply supported bridge using a suite of representative ground motions of the bridge region. The analyses are conducted separately on the pertinent issues that affect the performance of the new proposed system. As a part of the study, to identify the sensitivity of the new system and evaluate the overall seismic performance, several assessment parameters are utilized. The results show that the proposed system is efficient for reducing bridge responses as well as improving nonlinear performance of the columns during vertical and horizontal seismic excitations.

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Analytical Assessment of the Effect of Vertical Ground Motion on RC Frames Designed for Gravity Loads with Various Geometric Configurations

Advances in Civil Engineering ◽

10.1155/2018/4029142 ◽

2018 ◽

Vol 2018 ◽

pp. 1-11 ◽

Cited By ~ 1

Author(s):

Siyun Kim ◽

Sung Jig Kim ◽

Chunho Chang

Keyword(s):

Ground Motion ◽

Axial Force ◽

Local Level ◽

Time History ◽

Analytical Investigation ◽

Shear Capacity ◽

Rc Frames ◽

Geometric Configurations ◽

Vertical Ground Motion ◽

Vertical Ground

The paper presents an analytical investigation of the effect of vertical ground motion on the selected 13 reinforced concrete (RC) frames with different geometric configurations. For this purpose, earthquake ground motions with various vertical-to-horizontal peak acceleration ratios are selected to which a suitable scale factor is applied to match with seismic hazards of Korea. The methodology involves the evaluation of the structural responses of RC frames subjected to the selected records by means of nonlinear time history analyses. The results from the analysis are compared with results from studies of the case of horizontal-only excitation. The effect of the vertical earthquake component on damage of RC frames is considered at both the global and the local levels. The effect of vertical ground motion on axial force, shear demand, and shear capacity of RC columns is investigated to assess failure on a local level. In particular, the shear capacity is evaluated by using both the conservative method of a design code and more realistic predictive approaches. The results of the extensive analyses indicate that vertical ground motion can significantly affect the response of RC members in terms of axial force variation and shear capacity. These results point to the conclusion that vertical ground motion needs to be included in analysis for assessment and design.

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Ground Motion Prediction Equations for the Vertical Ground Motion Component Based on the NGA-W2 Database

Earthquake Spectra ◽

10.1193/121814eqs213m ◽

2017 ◽

Vol 33 (2) ◽

pp. 499-528 ◽

Cited By ~ 12

Author(s):

Zeynep Gülerce ◽

Ronnie Kamai ◽

Norman A. Abrahamson ◽

Walter J. Silva

Keyword(s):

Ground Motion ◽

Site Response ◽

Vertical Component ◽

Weighted Average ◽

Motion Models ◽

Nonlinear Site Response ◽

Vertical Ground Motion ◽

Vertical Ground ◽

Standard Deviations ◽

Ground Motion Models

Empirical ground motion models for the vertical component from shallow crustal earthquakes in active tectonic regions are derived using the PEER NGA-West2 database. The model is applicable to magnitudes 3.0–8.0, distances of 0–300 km, and spectral periods of 0–10 s. The model input parameters are the same as used by Abrahamson et al. (2014) except that the nonlinear site response and depth to bedrock effects are evaluated but found to be insignificant. Regional differences in large distance attenuation and site amplification scaling between California, Japan, China, Taiwan, Italy, and the Middle East are included. Scaling for the hanging-wall effect is incorporated using the constraints from numerical simulations by Donahue and Abrahamson (2014) . The standard deviation is magnitude dependent with smaller magnitudes leading to larger standard deviations at short periods but smaller standard deviations at long periods. The vertical ground motion model developed in this study can be paired with the horizontal component model proposed by Abrahamson et al. (2014) to produce a V/H ratio. For applications where the horizontal spectrum is derived from the weighted average of several horizontal ground motion models, a V/H model derived directly from the V/H data (such as Gülerce and Abrahamson 2011 ) should be preferred.

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How significant is vertical ground motion from low magnitude earthquakes?

10.5194/egusphere-egu2020-5505 ◽

2020 ◽

Author(s):

Janneke van Ginkel ◽

Elmer Ruigrok ◽

Rien Herber

Keyword(s):

The Netherlands ◽

Ground Motion ◽

Hazard Assessment ◽

Site Response ◽

Ground Motions ◽

Vertical Component ◽

Vertical Motion ◽

Vertical Ground Motion ◽

Vertical Ground ◽

Low Magnitude

Up to now, almost all of the ground motion modeling and hazard assessment for seismicity in the Netherlands focuses on horizontal motion. As a rule of thumb, the strength of vertical ground motions is taken as 2/3 of that of horizontal ground motions. In reality of course, amplifications and V/H ratios are site-dependent and thus vary regionally.&#160; Recent studies have indeed shown that vertical ground motion is not always simply 2/3 of the horizontal motion. However, these studies are performed in areas with high magnitude (Mw>5.0) earthquakes and the question is whether vertical motion is relevant to be included in seismic hazard assessment for low magnitude earthquakes (to date, max Mw=3.6 in Groningen).In the Netherlands, the top part of the soils is practically always unconsolidated, so the elastic waves generated by deeper (~3000m) seated earthquakes will be subject to transformation when arriving in these layers. Recordings over a range of depth levels in the Groningen borehole network show the largest amplification to occur in the upper 50 meters of the sedimentary cover. We not only observe a strong amplification from shear waves on the horizontal components, but also from longitudinal waves on the vertical component. A better understanding of vertical motion of low magnitude earthquakes aims to support the design of re-enforcement measures for buildings in areas affected by low magnitude seismicity. Furthermore, interference between the longitudinal -and shear waves might contribute to damage on structures.This study presents observations of longitudinal wave amplification in the frequency band 1-10 Hz, corresponding to resonance periods of Dutch buildings. From 19 seismic events, with a minimum of magnitude two, we retrieved transfer functions (TFs) from the vertical component, showing a strong site response at certain locations. In addition, we calculate event V/H ratios and VH factors from the surface seismometer. These results are compared with the TFs and show a similar pattern in terms of site response. Furthermore, the sites with highest vertical amplification correspond to very low (800-900 m/s) P-wave velocities. Our study shows that vertical amplification is very site dependent. However, the question whether the vertical motion is significant enough to form a real hazard can only be answered through cooperation between seismologist and structural engineer.

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