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... to the mass scale factor of 1/100, a scaled mass of 8.55 tons for a single span of the model superstructure is required. A 6 m-long steel Fig. 2 Design details of tested bridge model Shake Table 1 Shake Table 2 Shake box girder weighing 4.55 tons plus two superimposed mass blocks each weighing 2.0 tons are assembled to provide necessary superstructure mass. As one of the most crucial earthquake-resisting components, the bridge piers should be properly designed such that their capacities (e.g., axial, shear and flexural) match well with those of the prototype following the scale factors. ...Context 2
... the mechanical properties of the prototype and model bearings can be calculated, as summarized in Table 1. It can be seen from Table 1 that although the sizes of the model bearing are not strictly designed according to the scale factors of dimension, the critical mechanical properties of the model bearing are found to match well with the corresponding ones of the prototype bearing with negligible errors. ...Context 3
... the mechanical properties of the prototype and model bearings can be calculated, as summarized in Table 1. It can be seen from Table 1 that although the sizes of the model bearing are not strictly designed according to the scale factors of dimension, the critical mechanical properties of the model bearing are found to match well with the corresponding ones of the prototype bearing with negligible errors. Fig. 2 also gives the design details of the shear key used in the model. ...Similar publications
Citations
... Goel and Chopra [18] studied the seismic responses of an ordinary bridge across a strike-slip fault under three shear key conditions, demonstrating that the upper limit of the pier drift and abutment-girder displacement could be evaluated by the bridge with and without the elastic shear key, respectively. Xiang et al. [19] and Yi et al. [20] conducted shake table tests to analyze the seismic responses of simply-supported bridges crossing strike-slip faults perpendicularly. Xiang et al. [19] found that the transverse shear key substantially reduced the bearing displacement at the near-fault and cross-fault spans, especially when the bridge suffered large PD. ...
... Xiang et al. [19] and Yi et al. [20] conducted shake table tests to analyze the seismic responses of simply-supported bridges crossing strike-slip faults perpendicularly. Xiang et al. [19] found that the transverse shear key substantially reduced the bearing displacement at the near-fault and cross-fault spans, especially when the bridge suffered large PD. Yi et al. [20] concluded that a lead rubber bearing protected the girder and pier at the expense of large bearing displacements. ...
This study investigates the nonlinear seismic responses of a long-span suspension bridge crossing strike-slip faults and their sensitivity to various parameters and conditions. Four sets of near-fault records containing forward directivity and fling-step effects are selected, corrected, and then incorporated into the analysis. Empirical model is proposed using 54 sets of near-fault records to evaluate the dynamic pulse amplitude in fling-step ground motions. A simplified scaling method considering self-consistency is proposed to obtain the fling-step ground motions with different fault static offset and dynamic pulse amplitude. Multiple parameter method is derived by theoretical analysis to consider the effect of the fault-crossing angle on the wave propagation distance and direction. A nonlinear numerical model of double-pylon suspension bridge is established to study the seismic responses of near-fault and fault-crossing suspension bridges. The results indicate that the girder of the faultcrossing bridge rotates around the midspan, and the most of the bridge responses are slightly smaller than those of the near-fault case, whereas the transverse residual bearing displacement is substantially higher. Moreover, the sensitivity of the bridge responses to the fault-crossing angle, fault-crossing location, permanent displacement, dynamic pulse-type motion, ground motion component, and wave passage effect is comprehensively investigated. The minimum bridge responses, except for the residual bearing displacement, are obtained at a fault-crossing angle of 90 ◦ and a fault-crossing location at the middle span. The effects of the permanent displacement, dynamic pulse-type motion, and apparent wave velocity on the bridge responses are highly correlated with the fault-crossing angle. At a fault-crossing angle of 90◦, all bridge responses are insensitive to these parameters, except that the peak transverse pylon drift and the bearing displacement increase considerably with the increasing amplitude of dynamic pulse-type motion. When the fault-crossing angle is acute (obtuse), the wave passage has a considerable effect on the bridge responses, and most of the bridge responses increase significantly with an increase in the permanent displacement and dynamic pulse-type motion. However, the permanent displacement has a negligible effect on the peak pylon drift. The wave passage effect is more reasonable to be considered using the apparent wave velocity in the horizontal direction than in the bridge axis direction because the influence of the fault-crossing angle on the propagation distance and direction is taken into account. Furthermore, the vertical component exerts a minimal effect on all bridge responses, whereas the faultnormal component significantly affects most bridge responses.
... The specific behaviour of sliding isolation devices is described in various published papers [5][6][7], including simple pendulum isolation devices [8,9] and experimental tests were conducted in [10,11]. The basic concepts of some specific devices for energy dissipation, as well as some displacement-limiting devices, have also been introduced [12][13][14]. Specific U-shaped hysteretic steel dampers were developed and mainly used for buildings [15][16][17]. Lately, new developments include studies related to phenomena and/or concepts such as pounding effects [18], axial behaviour of elastomeric isolation devices [19], or semiactive dampers [20,21]. ...
The conducted extensive experimental seismic analysis showed seismic performances of a constructed large-scale bridge model representing system of upgraded isolated bridge with uniform gapped horizontal S-shaped devices (GHS System). The GHS system constituted double spherical rolling isolating bearings (DSRIB) and created original uniform horizontal S-shaped multi-gap (HS-MG) energy dissipation devices. With conducted laboratory cyclic tests, stable all-directional hysteretic responses were confirmed for both the DSRIB and HS-MG devices. In the dynamic seismic shaking table testing, the GHS bridge system showed favourable seismic response performances contributing to efficient bridge system protection. The established new GHS system exhibited large potential for qualitative improvement of seismic safety of isolated bridges exposed to very strong earthquakes. Poboljšanje mostova s potresnom izolacijom primjenom horizontalnih uređaja S-oblika (HS) Na modelu izvedenom u velikom mjerilu provedena su opsežna eksperimentalna ispitivanja na potresnu pobudu koja su pokazala odziv mosta s izolacijom poboljšanog primjenom horizontalnih uređaja S-oblika (HS) koji omogućavaju ograničene pomake (GHS sustav). GHS sustav je sastavljen od dvostrukih sfernih kotrljajućih izolacijskih ležajeva (DSRIB) i razvijenih originalnih uređaja za trošenje energije s komponentama S-oblika (HS-MG). Vrlo stabilni odzivi u svim smjerovima su potvrđeni laboratorijskim cikličnim testovima za oba uređaja, DSRIB i HS-MG. U eksperimentalnom ispitivanju na potresnom stolu, GHS izolacijski sustav mosta je pokazao povoljno ponašanje pri potresnom djelovanju pridonoseći učinkovitoj zaštiti mosta. Novi GHS sustav pokazao je veliki potencijal za kvalitativno poboljšanje sigurnosti mostova s potresnom izolacijom izloženih vrlo jakim potresima.
... The specific behaviour of sliding isolation devices is described in various published papers [5][6][7], including simple pendulum isolation devices [8,9] and experimental tests were conducted in [10,11]. The basic concepts of some specific devices for energy dissipation, as well as some displacement-limiting devices, have also been introduced [12][13][14]. Specific U-shaped hysteretic steel dampers were developed and mainly used for buildings [15][16][17]. Lately, new developments include studies related to phenomena and/or concepts such as pounding effects [18], axial behaviour of elastomeric isolation devices [19], or semiactive dampers [20,21]. ...
The conducted extensive experimental seismic analysis showed seismic performances of a constructed large-scale bridge model representing system of upgraded isolated bridge with uniform gapped horizontal S-shaped devices (GHS System). The GHS system constituted double spherical rolling isolating bearings (DSRIB) and created original uniform horizontal S-shaped multi-gap (HS-MG) energy dissipation devices. With conducted laboratory cyclic tests, stable all-directional hysteretic responses were confirmed for both the DSRIB and HS-MG devices. In the dynamic seismic shaking table testing, the GHS bridge system showed favourable seismic response performances contributing to efficient bridge system protection. The established new GHS system exhibited large potential for qualitative improvement of seismic safety of isolated bridges exposed to very strong earthquakes. Poboljšanje mostova s potresnom izolacijom primjenom horizontalnih uređaja S-oblika (HS) Na modelu izvedenom u velikom mjerilu provedena su opsežna eksperimentalna ispitivanja na potresnu pobudu koja su pokazala odziv mosta s izolacijom poboljšanog primjenom horizontalnih uređaja S-oblika (HS) koji omogućavaju ograničene pomake (GHS sustav). GHS sustav je sastavljen od dvostrukih sfernih kotrljajućih izolacijskih ležajeva (DSRIB) i razvijenih originalnih uređaja za trošenje energije s komponentama S-oblika (HS-MG). Vrlo stabilni odzivi u svim smjerovima su potvrđeni laboratorijskim cikličnim testovima za oba uređaja, DSRIB i HS-MG. U eksperimentalnom ispitivanju na potresnom stolu, GHS izolacijski sustav mosta je pokazao povoljno ponašanje pri potresnom djelovanju pridonoseći učinkovitoj zaštiti mosta. Novi GHS sustav pokazao je veliki potencijal za kvalitativno poboljšanje sigurnosti mostova s potresnom izolacijom izloženih vrlo jakim potresima.
... Several studies have performed the small-scale fault model experiments [14,15] and large-scale shake table tests [16][17][18][19] of short-span fault-crossing bridges and pier foundations. Murono et al. [14] carried out a 1/50 scale bridge model across a strike-slip fault and determined that the margin length required to prevent girder falling decreased considerably as the fault-crossing angle approach 90 • . ...
... Saiidi et al. [16] examined a 1/4 scale two-span RC bridge across fault and determined that the tallest pier close to the fault suffered the severest damage. Yi et al. [17] and Xiang et al. [18] examined a 1/10 scale isolated simply-supported bridge across fault and observed that the lead lubber bearings under the near fault span were more vulnerable than the bearings under the across-fault span. By testing a 1/10 scale steel--concrete composite rigid-frame bridge across a thrust fault, Lin et al. [19] reported that the fault location, fault-crossing angle and the amplitude of the fling step exerted a considerable influence on the seismic response of this bridge. ...
Bridge structures across active faults suffer the serious threats from large surface deformation and velocity pulses. This study focuses on developing a multi-criteria optimizing method and investigating the damping effect of the optimized damper system on a cable-stayed bridge across a strike-slip fault. A simplified baseline corrected method is adopted to recover the static offsets in near-fault records and the improved record-decomposition incorporation method is modified to produce artificial across-fault ground motions. A single pylon cable-stayed bridge across a strike-slip fault is taken as the case bridge and the refined nonlinear numerical model is established in OpenSees. The conventional multi-criteria decision making (MCDM) theory is improved by introducing new function forms and a control parameter to assess the best fault-crossing angles of the case bridge. The improved MCDM method is integrated with the beetle antennae search algorithm to optimize the damper system of the case bridge. Finally, the influence of fault-crossing angles and earthquake parameters (permanent displacements and ratios of maximum to permanent displacement) on the damping effect of the optimized damper system are investigated. The results indicate that the cable-stayed bridge reaches optimal seismic performance when the fault-crossing angle is around 90° (75°-105°) as both the biaxial nonlinearity of the pylon and the risk of the girder unseating are reduced. The damper system is efficiently optimized by the proposed method, and the displacement and force demand of the case bridge are balanced. Both the fault-crossing angles and earthquake parameters are observed to have considerable influence on the damping effects. More specifically, the damping effect on most seismic responses is optimized when the fault-crossing angle approaches 90° (60°-120°). As the permanent displacement increases, the damping effect on the pier-girder relative displacement is significantly reduced and the damping effect on the pier moments is moderately decreased. Moreover, the damping effect is improved for all the seismic responses as the ratios of maximum to permanent displacements increase, with the exception of transverse displacement.
... The specific behavior of sliding bearings can be perceived based on the research results obtained by Dolce et al. (2007), Iemura et al. (2007) or Kartoum et al. (1992), while simple pendulum seismic bearings were considered by Wang et al. (1998) or Zayas et al. (1990), experimentally verified by Mokha et al. (1990) and Constantinou et al. (1992), and successfully implemented in the current practice. The widely studied (Xiang et al., 2019) and adopted isolation technology has been upgraded with various dissipative mechanisms to protect structures from near-source ground motions. The concepts and application of additional proposed devices for energy dissipation, along with large-displacement-limiting devices, were introduced and investigated by Skinner et al. (1975) or Guan et al. (2010). ...
The results of the experimental research program realized on a bridge model constructed by using the seismically isolated system upgraded with space-bar devices (USI-SB) are presented in the paper. The installed adaptable system for seismic protection of bridges utilizes double spherical rolling seismic bearings (DSRSB) as seismic isolators, while the qualitative improvement of seismic performances is achieved through the use of novel adjustable multi-directional space-bar energy dissipation (SB-ED) devices. The experimental program consisted of quasi-static testing of isolation and energy dissipation devices under the cyclic loading and extensive shaking-table testing of a large-scale bridge model with installed USI-SB system. For both types of devices, a very stable all-directional response during cycling tests, as well as the favorable hysteretic behavior of the energy dissipation devices along the entire range of applied large displacements were registered. In the dynamic testing, the system showed high seismic response modification performances needed for the efficient protection, exhibiting its large potential in the qualitative improvement of seismic performances of isolated bridges.
... In the past two decades, the seismic performances of bridge structures crossing fault-rupture zones have been investigated theoretically [13,[22][23][24], experimentally [25][26][27][28] and numerically [6,7,[29][30][31]. For example, Goel and Chopra [13,22] proposed approximate procedures to estimate the peak responses of bridges crossing fault-rupture zones based on the structural dynamics theory. ...
Bridges crossing fault are vulnerable to surface fault ruptures. Previous studies on this topic are limited especially for thrust faults. It is necessary to examine the performances of fault-crossing bridges subjected to earthquake-induced surface fault rupture. This study investigates the seismic behavior of a recently proposed steel-concrete composite rigid-frame bridge (SCCRFB) with concrete-filled double skin steel tube (CFDST) piers subjected to the earthquake-induced surface rupture at a thrust fault. Shake table tests on a 1:10 scaled three-span SCCRFB subjected to across-fault ground motions were performed first. Detailed 3D finite element (FE) model of the bridge is then developed by using LS-DYNA and validated by the experimental results. The effects of the key parameters that influence the bridge responses to surface ruptures including the location of the fault, fault-crossing angle and fling-step are systematically investigated. Experimental and numerical results reveal that this novel bridge type has a very good seismic resistance capability.
Recent seismic events have unequivocally highlighted the susceptibility of fault-crossing bridges to the synergistic effects of ground surface vibrations on either side of the fault plane and the tectonic dislocations arising from fault-induced surface ruptures. This study delineates both seismic and parametric response analyses of fault-crossing suspension bridges, employing a straightforward yet efficacious method for simulating desired ground motions near fault-rupture zones. Herein, we introduce a user-friendly method to incorporate predicted fault-induced displacements, accounting for both fling-step and directivity effects, into processed ground motion chronologies, enabling the generation of dip-slip fault ground motions. The accuracy and efficacy of the proposed method are affirmed by juxtaposing the generated ground motions with the observed ones (MGM). An exhaustive parametric analysis, addressing factors like fault-crossing location, fault-crossing angle, and frequency components of fault-crossing ground motions, of a suspension bridge over a rupture fault, is executed using the fashionable ANSYS software. This study provides clear and specific guidelines for the seismic design of suspension bridges traversing rupture faults.
Bridges crossing active faults are more likely to suffer serious damage or even collapse due to the wreck capabilities of near-fault pulses and surface ruptures under earthquakes. Taking a high-speed railway simply-supported girder bridge with eight spans crossing an active strike-slip fault as the research object, a refined coupling dynamic model of the high-speed train-CRTS III slab ballastless track-bridge system was established based on ABAQUS. The rationality of the established model was thoroughly discussed. The horizontal ground motions in a fault rupture zone were simulated and transient dynamic analyses of the high-speed train-track-bridge coupling system under 3-dimensional seismic excitations were subsequently performed. The safe running speed limits of a high-speed train under different earthquake levels (frequent occurrence, design and rare occurrence) were assessed based on wheel-rail dynamic (lateral wheel-rail force, derailment coefficient and wheel-load reduction rate) and rail deformation (rail dislocation, parallel turning angle and turning angle) indicators. Parameter optimization was then investigated in terms of the rail fastener stiffness and isolation layer friction coefficient. Results of the wheel-rail dynamic indicators demonstrate the safe running speed limits for the high-speed train to be approximately 200 km/h and 80 km/h under frequent and design earthquakes, while the train is unable to run safely under rare earthquakes. In addition, the rail deformations under frequent, design and rare earthquakes meet the safe running requirements of the high-speed train for the speeds of 250, 100 and 50 km/h, respectively. The speed limits determined for the wheel-rail dynamic indicators are lower due to the complex coupling effect of the train-track-bridge system under track irregularity. The running safety of the train was improved by increasing the fastener stiffness and isolation layer friction coefficient. At the rail fastener lateral stiffness of 60 kN/mm and isolation layer friction coefficients of 0.9 and 0.8, respectively, the safe running speed limits of the high-speed train increased to 250 km/h and 100 km/h under frequent and design earthquakes, respectively.
