Effect of the spatial variability of ground motions on the seismic response of reinforced concrete highway bridges

2021 ◽  
Author(s):  
Lei Lou
Keyword(s):  
Reinforced Concrete ◽  
Spatial Variability ◽  
Seismic Response ◽  
Ground Motions ◽  
Highway Bridges

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

2010 ◽  
Vol 26 (4) ◽  
pp. 999-1016 ◽  
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.

Dimension and Frequency Profiles of Concrete Highway Bridges in New Madrid Region of Southeastern Missouri

1997 ◽  
Vol 1594 (1) ◽  
pp. 84-93 ◽  
Author(s):  
Ralph Alan Dusseau
Keyword(s):  
Reinforced Concrete ◽  
Concrete Slab ◽  
Highway Bridges ◽  
Ambient Vibration ◽  
Earthquake Hazards ◽  
Empirical Formulas ◽  
Reinforced Concrete Slab ◽  
Box Girder ◽  
Bridge Spans ◽  
New Madrid

The results of a study funded by the U.S. Geological Survey as part of the National Earthquake Hazards Reduction Program are presented. The first objective of this study was the development of a database for all 211 highway bridges along I-55 in the New Madrid region of southeastern Missouri. Profiles for five key dimension parameters (which are stored in the database) were developed, and the results for concrete highway bridges are presented. The second objective was to perform field ambient vibration analyses on 25 typical highway bridge spans along the I-55 corridor to determine the fundamental vertical and lateral frequencies of the bridge spans measured. These 25 spans included six reinforced concrete slab spans and two reinforced concrete box-girder spans. The third objective was to use these bridge frequency results in conjunction with the dimension parameters stored in the database to develop empirical formulas for estimating bridge fundamental natural frequencies. These formulas were applied to all 211 Interstate highway bridges in southeastern Missouri. Profiles for both fundamental vertical and lateral frequencies were then developed, and the results for concrete highway bridges are presented.

Effects of Fling Step and Forward Directivity on Seismic Response of Buildings

2006 ◽  
Vol 22 (2) ◽  
pp. 367-390 ◽  
Author(s):  
Erol Kalkan ◽  
Sashi K. Kunnath
Keyword(s):  
Seismic Response ◽  
Ground Motions ◽  
High Amplitude ◽  
Moment Frames ◽  
Steel Moment Frames ◽  
Damage Potential ◽  
Near Fault ◽  
Forward Directivity ◽  
Fling Step ◽  
Far Fault

This paper investigates the consequences of well-known characteristics of near-fault ground motions on the seismic response of steel moment frames. Additionally, idealized pulses are utilized in a separate study to gain further insight into the effects of high-amplitude pulses on structural demands. Simple input pulses were also synthesized to simulate artificial fling-step effects in ground motions originally having forward directivity. Findings from the study reveal that median maximum demands and the dispersion in the peak values were higher for near-fault records than far-fault motions. The arrival of the velocity pulse in a near-fault record causes the structure to dissipate considerable input energy in relatively few plastic cycles, whereas cumulative effects from increased cyclic demands are more pronounced in far-fault records. For pulse-type input, the maximum demand is a function of the ratio of the pulse period to the fundamental period of the structure. Records with fling effects were found to excite systems primarily in their fundamental mode while waveforms with forward directivity in the absence of fling caused higher modes to be activated. It is concluded that the acceleration and velocity spectra, when examined collectively, can be utilized to reasonably assess the damage potential of near-fault records.

scholarly journals Probabilistic seismic response analysis of coastal highway bridges under scour and liquefaction conditions: does the hydrodynamic effect matter?

2020 ◽  
Vol 1 (1) ◽  
Author(s):  
Xiaowei Wang ◽  
Yutao Pang ◽  
Aijun Ye
Keyword(s):  
Seismic Response ◽  
Seismic Design ◽  
Highway Bridges ◽  
Element Model ◽  
Response Analysis ◽  
Hydrodynamic Effect ◽  
Strong Earthquakes ◽  
Influence Of Water ◽  
Scour Hazard ◽  
Ground Motion Records

AbstractCoastal highway bridges are usually supported by pile foundations that are submerged in water and embedded into saturated soils. Such sites have been reported susceptible to scour hazard and probably liquefied under strong earthquakes. Existing studies on seismic response analyses of such bridges often ignore the influence of water-induced hydrodynamic effect. This study assesses quantitative impacts of the hydrodynamic effect on seismic responses of coastal highway bridges under scour and liquefaction potential in a probabilistic manner. A coupled soil-bridge finite element model that represents typical coastal highway bridges is excited by two sets of ground motion records that represent two seismic design levels (i.e., low versus high in terms of 10%-50 years versus 2%-50 years). Modeled by the added mass method, the hydrodynamic effect on responses of bridge key components including the bearing deformation, column curvature, and pile curvature is systematically quantified for scenarios with and without liquefaction across different scour depths. It is found that the influence of hydrodynamic effect becomes more noticeable with the increase of scour depths. Nevertheless, it has minor influence on the bearing deformation and column curvature (i.e., percentage changes of the responses are within 5%), regardless of the liquefiable or nonliquefiable scenario under the low or high seismic design level. As for the pile curvature, the hydrodynamic effect under the low seismic design level may remarkably increase the response by as large as 15%–20%, whereas under the high seismic design level, it has ignorable influence on the pile curvature.

Sign in / Sign up

Export Citation Format

Share Document