20 December 2017, Volume 30 Issue 12
    

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    China Journal of Highway and Transport. 2017, 30(12): 1-1.
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  • LI Jian-zhong, GUAN Zhong-guo
    China Journal of Highway and Transport. 2017, 30(12): 1-9,59.
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    In order to summarize the status and further research concerns of the theory and technology in seismic design for bridges, a brief review on state of the art of bridge seismic design was conducted. The design process based on component strength of a ductile system was introduced, and the framework and progress of the performance-based seismic design theory for bridges were expressed and discussed. Specifically, the displacement-based seismic design process and the full probability seismic design and evaluation method were introduced. The isolation and energy dissipation devices that were frequently used in practical bridges were briefly reviewed, including the configuration, the isolation mechanism, the analysis model, and the applications. The recent progress in seismic isolation for bridges and energy dissipation technique was introduced and discussed. The design objective of bridge seismic isolation was changing from seismic responses alleviation to structural performance control, including the performance control of the isolation system under the non-seismic loading and the post-earthquake structural performance and rehabilitation requirements during the life cycle. The recent research focus, for example, the new type of post-earthquake structural systems of resilience was discussed. The detailed configuration and mechanism of rocking foundation and prestressed segmental bridge columns were introduced, and advantages of resilient systems in post-earthquake performance were analyzed. Furthermore, the major concerns in bridge seismic design in the near future were discussed. Meanwhile, new design methods and new structural systems of bridges with recentering capacity and low damage features will be primarily concerned.
  • YANG You-fu, LIU Min
    China Journal of Highway and Transport. 2017, 30(12): 10-20.
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    To provide references for the research, design and construction of the bridge pier, bridge tower and arch rib of arch bridge with concrete-filled steel tube (CFST) latticed members, the progress of the research on the seismic performance of CFST latticed members at home and abroad, including experimental investigations, theoretical analysis and restoring force model, was systematically expounded. The results show that the experimental investigation on hysteretic performance of CFST latticed piers mainly focuses on the specimens with circular limbs subjected to uniaxially cyclic loading, and both the experimental objects and the range of parameters are limited. The reports of pseudo-dynamic test of CFST latticed piers and shaking table test of CFST latticed arch bridge model are rare, and research objects are single with the limited experimental conditions. Meanwhile, although theoretical models for hysteretic behavior constructed by different researchers can simulate the performance and failure process of CFST latticed piers to a certain extent, there is the shortcoming or unreasonable aspect. The rationality of the available model for CFST latticed arch bridge needs to be further verified due to the simplicity of members or joints in the real structures. Based on the analysis of the research status at home and abroad, it is pointed out that analytical theory and model for hysteretic behavior under strong nonlinear conditions, the damage evolution rule and failure criterion, as well as restoring force model and seismic design method are the key scientific issues while performing the research on seismic behavior of CFST latticed members. Finally, the outlook for the prospects and development direction of the research on the seismic behavior of CFST latticed members is made to offer the research ideas for intensive research on the behavior of CFST latticed bridge pier, bridge tower and arch rib of arch bridge under the action of earthquake, reasonable assessment of the earthquake damage evolution rule of such a kind of structural members and further development of rational seismic design method of CFST latticed bridge pier, bridge tower and arch rib of arch bridge.
  • YE Ai-jun, FANG Jia-xin, ZHANG Shao-wei, WANG Xiao-wei
    China Journal of Highway and Transport. 2017, 30(12): 21-29.
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    In order to improve the transverse seismic performance of multi-box girder bridges, two transverse seismic systems taking triangular steel plates as energy dissipation elements were proposed. One is a combination of the laminated rubber bearings (LRBs) with steel dampers (denoted by L-D system), whilst the other is a combination of the LRBs with steel blocks (denoted by L-B system). The structural characteristics and mechanical characteristics of the two kinds of shock absorbers were described in detail. The gap between girder and steel blocks of L-B system is the displacement when the girder begins to slide on the laminated rubber bearing, so as to make full use of bearings' shock absorption capacity. Taking simplified multi-box girder bridges as an example, the influence of the yield force of two kinds of shock absorbers on shock absorption effect was investigated by dint of the same costs. Besides, a method for determining the key parameters of the seismic systems was proposed, and an in-depth nonlinear time-history analysis was performed to investigate characteristics of energy dissipation. Two typical ground motions were input to suspect the effect of the maximum relative displacement of pier and beam, the maximum pier bottom moment and the respective energy dissipation mechanism. The results indicate the L-D system provides an excellent energy dissipation capacity as well as a relatively large restoring force, so L-D system can control the pier-deck relative displacement by both energy dissipation and resilience. Whereas the L-B system consumes much less energy and restrains the pier-deck relative displacement, simply by providing a normal restoring force. The limit effect of L-D system is better than that of L-B system. The increase of yield forces for the steel dampers or blocks (at a certain range) can significantly reduce the maximum pier-deck relative displacement while the seismic force which is transmitted to the substructure slightly increases. When the ground motion input is not evenly distributed in both directions, the girder in L-B system will hit one side of blocks more frequently and the number of hysteresis loops in the block will be significantly reduced, resulting in the potential damage of bearings. However, the L-D system can better adapt to the different seismic inputs.
  • WANG Jing-quan, LI Shuai, ZHANG Fan
    China Journal of Highway and Transport. 2017, 30(12): 30-39.
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    In order to improve the seismic performance of long-span cable-stayed bridge, a new shape memory alloy (SMA)-based rubber bearing was proposed. The Sutong cable-stayed bridge in China was taken as an object of the research. Two types of isolation devices, namely, lead rubber bearing (LRB) and SMA-based lead rubber bearing (SMA-LRB), were installed to control the structural responses. About 20 near-fault ground motions were selected from PEER strong ground motion database as the input. The seismic responses of the bridge were obtained by the incremental dynamic analyses (IDA) method. The fragility curves of the bridge and its components were established by dint of the probabilistic seismic demand model (PSDM). The seismic fragility of the cable-stayed bridges equipped with LRB and SMA-LRB was evaluated. Results show that the damage probability of the cable-stayed bridge is higher than that of each component. The isolation bearings are the most vulnerable component in the moderate, severe and collapse damage state under near-fault ground motions. The towers with a low damage probability present the slight damage. The bridge system equipped with SMA-LRB undergoes damage with a smaller risk, compared with LRB. There is a low probability for the bridge tower, pier, and cable to occur the collapse damage under strong ground motions. The probabilities of the bridge equipped with LRB and SMA-LRB are 0.07 and 0.009, respectively, in the collapse damage state under severe ground motions. It means that such bridge structures show good seismic performance.
  • SUN Zhi-guo, GU Ming-yang, SI Bing-jun, ZHOU Ying-wu
    China Journal of Highway and Transport. 2017, 30(12): 40-49.
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    In allusion to the construction advantage of the precast-assembly structure and good seismic behavior of the rocking self-centering structure, two innovative rocking self-centering double column bridge bents were proposed. One was designed with external angles and the other with external angles and energy dissipation bars. The detailed finite analysis models for both of the bents based on OpenSees platform were established, and the accuracy of the models was verified by comparing with cyclic tension and compression test results for angles and quasi-static test results for rocking self-centering double column bents. On this basis, the seismic behavior of the rocking self-centering bents were investigated by quasi-static and dynamic time-history analysis results of the bents, and the behavior of the rocking self-centering bents was compared with that of commonly used reinforced concrete bents. The results show that, compared with commonly used bents, both of the rocking self-centering bents show smaller initial lateral stiffness and larger natural vibration period. The prestressing tendon in the elastic stage shows negligible residual displacement under 0.4g near-fault ground motions, which is beneficial for rehabilitation of the double column bridge bents. The external angles may yield and absorb seismic energy under 0.1g near-fault ground motions and will be fractured under 0.4g near-fault ground motions. When the rocking self-centering bents are designed with some energy dissipation bars with a reinforcement ratio less than 0.4%, the deformation of the bents, the prestressing stress of the tendons and the deformation of the angles will decrease, compared with the bents designed only with angles. And the energy dissipation bars induce a little increase for the residual displacement of the rocking self-centering double column bents.
  • HU Si-cong, LI Li-feng, WANG Lian-hua
    China Journal of Highway and Transport. 2017, 30(12): 50-59.
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    In order to investigate the seismic performance of multi-span cable-stayed bridges with tall piers, taking a five-span cable-stayed bridge with 178 m piers as an example, the finite element model of the bridge was developed and both the geometric and material nonlinearities were considered. 80 long-period and short-period ground motions were selected to conduct the nonlinear time history analysis. Based on 4 kinds of engineering demand parameters of cable-stayed bridges, the efficiency, the practicality and the proficiency of 9 kinds of ground motions intensity measures (IMs) were evaluated using the regression analysis method, and the selection suggestion of IMs was proposed. Moreover, the damage indexes of various components including bearing system, tower, deck and cable were defined according to the damage characteristic of bridge. Based on the fragility method, component fragility curves were developed. The vulnerable location of each kind of components was determined and the damages of various components were compared. Furthermore, design considerations for improving the seismic performance of the cable-stayed bridge with tall piers were proposed. The results show that the optimal IMs of regular bridges are unfit for multi-span cable-stayed bridges with tall piers to predict seismic response. Depending on different cases, spectral acceleration at first frequency and peak spectrum displacement are suitable for this kind of bridge. The bearing system, deck and cables present higher damage probability than towers under longitudinal ground motions. The damages of 1/4 and 3/4 mid-span of deck are serious. The damages of short cable in the side-span and long cable in the mid-span are serious amongst all the cables. As the damages of various components are mainly caused by the deformation of bridge, and the damages of tower are relatively slight, it's more important to control the displacement of bridge than inner force of tower while designing multi-span cable-stayed bridges with tall piers.
  • XIA Zhang-hua, ZONG Zhou-hong, XIA Jian, XUE Wan-shan, LIN Yuan-zheng
    China Journal of Highway and Transport. 2017, 30(12): 60-70,109.
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    In order to get the influence rule of the cumulative damage caused by the horizontal bilateral load coupling effect on the hysteretic behavior, strength and stiffness degradation of the reinforced concrete (RC) box pier, the biaxial restoring force model of the RC box pier was investigated. Firstly, the biaxial pseudo static test and finite element simulation of the RC box pier, considering axial load ratio, slenderness ratio, reinforcement ratio and loading angle, were conducted, and the calculation formula of the damage factor considering the bidirectional coupling load effect was also presented. Secondly, the skeleton curves of the testing piers were idealized as a three-line type model with the descending segment, and the calculation method of the skeleton curve and the corresponding stiffness for the RC box pier were established. Finally, the relation between the damage factor and the strength and stiffness degradation of the specimens were analyzed according to the characteristics of the experimental hysteretic curves, whilst the calculation formula of the load-steep-descending factor from the unloading point of the peak displacement was proposed. At the same time, the biaxial hysteresis rules of the box pier was given, and the damage-based biaxial restoring force model for the RC box pier was established. The results show that the calculating skeleton and hysteresis curves from the proposed restoring force model of the RC box piers agree well with results of the quasi-static testing, and the maximum error is less than 10%. The proposed model reflects the damage aggravated effects and hysteresis characteristics caused by horizontal bi-directional loading, so it will provide the theoretical reference for the multi-dimensional seismic analysis and design for the RC box pier.
  • SHAN De-shan, DONG Jun, LI Qiao, XIE Xiang-hui
    China Journal of Highway and Transport. 2017, 30(12): 71-80.
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    In allusion to the shortcomings of seismic vulnerability analysis methods commonly used in bridge structures, an algorithm based on the kernel density estimation for the seismic vulnerability analysis of the bridge component was proposed. Based on the basic definition of the conditional probability for structural seismic vulnerability, the vulnerability function was redefined. The assumption that the lognormal distribution of the vulnerability condition probability was discarded, and no assumptions were made for the relationship between seismic demand and capacity of the component in bridge structure. In light of the nonparametric estimation idea of the kernel density estimation in the probabilistic statistic discipline, the estimation of the joint probability density distribution function for the seismic intensity, seismic demand and the estimation of the probability density function for the marginal distribution function of the seismic intensity were achieved. Furthermore, the algorithm of kernel density estimation for the seismic vulnerability analysis of the bridge structural component was constructed accordingly. The validity and reliability of the vulnerability algorithm was verified by Bootstrap sampling method. Taking a certain rigid frame-continuous composite bridge as an example, its finite element model was established by dint of the OpenSees software platform in line with the current specification of bridge seismic design. Considering the uncertainty of structural parameters and the ground motion, the seismic vulnerability of the bridge component was analyzed based on the incremental dynamic analysis and kernel density estimation. Moreover, the maximum likelihood estimation and probabilistic seismic demand analysis of the parameter estimation methods and Monte Carlo simulation of the nonparametric methods for structural vulnerability analysis were adopted as well to figure out the seismic vulnerability curves. The seismic vulnerability curves obtained from these four methods of structural seismic vulnerability analysis were compared and discussed, and the accuracy and reliability of proposed method were verified. The result shows that the computational efficiency of the proposed seismic vulnerability analysis method based on the kernel density estimation is relatively high, and it can be used in the seismic vulnerability analysis of bridge structures.
  • XU Xiu-li, TANG Yu-sheng, ZHOU Ding, LI Xue-hong, YIN Dong-ya
    China Journal of Highway and Transport. 2017, 30(12): 81-88.
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    To deal with the difficulty in repairing conventional thin-walled structure of super high pier damaged by earthquake, a new high pier structure system with self-dissipation energy, composed of concrete corner columns, pre-fabricated steel coupling beams and concrete thin-walled plates, was proposed. The connection method was put forward to match with the new self-dissipation energy high pier system. By dint of this method, a one-way restraint with higher energy dissipation efficiency was adopted in the concrete thin-walled plate. Only the upper and the lower parts of the plate were connected with the steel beam by bolts, with a toothed concrete back pouring band ensuring their connection rigidity. The steel coupling beam with an I-shaped cross section was conducive to the connection with the concrete plate. The steel coupling beam was welded to the column with rigid connection in order to generate enough plastic hinges. The new self-dissipation energy high pier model at 1:15 on the premise of similar section characteristics with the reference of the thin-walled high pier bridge was designed. The seismic performances of the two piers were compared and analyzed by the low cyclic reversed loading test and numerical simulation. The manufacturing process of the test model further verified the convenience and feasibility of the structural design described above. The results show that in addition to the obvious advantages of easy restoration after the earthquake, the energy dissipation capacity, bearing capacity and ductility deformation capacity of the new self-dissipation energy high pier is better than those of the traditional thin-walled pier. Under the service load, new self-dissipation energy high pier has relatively large spatial stiffness. Under the design level earthquake, concrete thin-walled plate works as the primary energy dissipation component, with the priority in entering energy dissipation stage. Under the severe earthquake, steel coupling beams acts as the secondary energy dissipation component, yielding to dissipate energy in order to protect load-bearing column. After the earthquake, only the damaged thin-wall plate and the steel coupling beam need to be replaced to restore the structure.
  • JIANG Hui, JIN Jia-min, WANG Zhi-gang, BAI Xiao-yu, WANG Min
    China Journal of Highway and Transport. 2017, 30(12): 89-100.
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    In order to investigate the probabilistic seismic damage characteristics of deep-water continuous rigid frame bridges, three-span continuous rigid frame bridge of an expressway in deep water was taken as an object. The nonlinear finite element model of the bridge was established by OpenSees software, and the influence of pile-soil dynamic interaction and hydrodynamic effect for the submerged parts were considered. With grouped earthquake records matched with the code spectrum as the excitation, incremental dynamic analysis (IDA) was conducted for the bridge structure, under three conditions of waterless environment as well as water depths of 12 m and 27 m respectively. Taken the left double-wall pier of the main span as the object, the fractile IDA curves at probability levels of 16%, 50% and 84% and the fragility curves at different damage states were developed by probabilistic seismic demand analysis method. The results show that the natural vibration period of the bridge will be extended under the hydrodynamic effect. The curvature response of main sections increases with the increasing of the peak ground acceleration (PGA), and the bottom sections of the pier tends to enter the stage of "serious damage" and "complete destruction" with a higher probability than the top sections. In addition, the inside wall of the pier has greater exceedance probability than the outer wall at different damage levels. With the enlargement of water depth, the curvature of the bottom section increases and the exceedance probability under each damage state amplifies accordingly. When the PGA is 0.6g, the exceedance probabilities of "complete destruction" for the bottom section of the inside wall are 28.1%, 39.4% and 67.6%, respectively, under three kinds of water depths. The deep water environment will magnify significantly the damage exceedance probability for continuous rigid frame bridges under different seismic levels, and hence, more attention should be paid to it.
  • ZHONG Jian, REN Wei-xin, WAN Hua-ping, YUAN Wan-cheng
    China Journal of Highway and Transport. 2017, 30(12): 101-109.
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    In allusion to the problem of few researches on seismic fragility on the basis of structural performance under E1 and E2 earthquake in the Chinese code, the probabilistic methodology to evaluate the seismic performance of bridge under the two horizontal earthquake actions was proposed, and theoretical formula of seismic hazard under the design earthquake was deduced. This approach was exemplified in detail by a long-span cable-stayed bridge. The finite element model of a cable-stayed bridge was established considering a variety of nonlinear effects. The probabilistic seismic demand model (PSDM) and fragility functions of critical components (pylon, abutment, bearing, and fluid viscous damper) and bridge system of the cable-stayed bridge were established. Through the fitting of seismic hazard curvilinear equation, the damage probability of components and systems during different earthquake return period was obtained. The damage probability of the bridge under E1 and E2 earthquake was calculated using the closed form expression. The Monte Carlo simulation method was used to obtain the system fragility curves and seismic hazard based on the performance level of main components. The system fragility of cable-stayed bridge retrofitted with fluid viscous damper (FVD) and as-built bridge was compared under E1 and E2 earthquake based on the system fragility analysis methods for cable-stayed bridges under two-level seismic hazard. The result shows that the FVD can effectively reduce seismic risk of main components and structural systems of cable-stayed bridges under the design earthquake. This methodology will provide the theoretical approach for the performance-based probabilistic seismic design and retrofit of the cable-stayed bridges.
  • YI Jiang, LI Jian-zhong
    China Journal of Highway and Transport. 2017, 30(12): 110-118,138.
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    In order to explore the phenomenon of end span uplift for the cable-stayed bridge and the influence on structural seismic response, and to analyze influence factors of end span uplift, 3D nonlinear finite-element model of a single-tower cable-stayed bridge was established, in consideration of the end-span uplift. The model was then excited by seven real earthquake ground motions, and nonlinear time history analysis method was used to investigate end span uplift and its effect during the earthquake. The effectiveness of two measures to control end-span uplift effect were further discussed including implementing viscous damper to longitudinally connect the deck and the tower and introducing tensile devices to the deck and the pier. The results show that under longitudinal earthquake excitation, there are large impact forces of the bearing at the moment of re-contacting the deck with bearing after the end-span uplift and large vertical displacement at deck end. The end span uplift of the bending moment at the bottom of the pier and tower sections and displacement at deck end has a limited influence on the seismic response of whole structure. The vertical ground motions enlarge bearing force so that end-span uplift will be caused at smaller peak ground acceleration (PGA). Besides, viscous damper will fail to satisfy the requirement of controlling end span uplift effect. The tensile device is effective in controlling end span uplift along the vertical direction of the pier, but relatively large stiffness and tension forces of the device are required. By both viscous damper and tensile device, the stiffness and tension force of the tensile device is reduced and end span uplift effect is effectively controlled.
  • WANG Zhan-fei, LI Tian-yu, SUI Wei-ning, LI Guo-chang
    China Journal of Highway and Transport. 2017, 30(12): 119-128.
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    In order to widely apply partial concrete-filled steel bridge piers in the urban complicated traffic engineering, it was necessary to investigate the seismic performance of partial concrete-filled steel bridge pier with vertical eccentricity. The partial concrete-filled steel tubular bridge pier in inverse L-shape was taken to investigate the influence of design parameters including slenderness ratio, radius-thickness ratio and vertical load eccentricity ratio on the mechanical performance of such bridge piers along longitudinal direction through test and finite element analyses (FEA). First of all, finite element models of 4 partial concrete-filled steel tubular columns with vertical load eccentricity which had been tested previously were established. Through comparing values of FEA and experimental results, the rationality of selection, division, contact and boundary conditions of FE models was verified. Then, 30 partial concrete-filled steel tubular bridge piers were designed according to parameters of radius-thickness ratio Rt, slenderness ratio λ and vertical load eccentricity ratio e/L of bridge piers to conduct nonlinear FE analyses. The results show that in the case where other parameters is unchanged, when λ increases from 0.25 to 0.35, the bearing capacity and the ductility of bridge piers decreases. When Rt increases from 0.06 to 0.12, the bearing capacity increases and the ductility decreases. The bearing capacity and ductility of the bridge piers decreases with the increase of eccentricity ratio e/L, and seismic performance is poor. When e/L increases from 0 to 0.2, the bearing capacity and ductility of bridge piers decrease by about 24% and 50%, respectively. The results of the research have provided the theoretical basis for engineering application on this kind of bridge piers under the complicated load condition.
  • WANG Zhen, WANG Jing-quan, XIU Hong-liang, LIU Tong-xu
    China Journal of Highway and Transport. 2017, 30(12): 129-138.
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    To establish the hysteretic model of reinforced concrete rectangular bridge columns with flexure-shear failure mode, a criterion was put forward to verdict different failure modes of bridge columns based on existing trial results. According to Ibarra-Medina-Krawinkler model, the skeleton curve of rectangular bridge columns with flexure-shear failure mode was simplified into four lines, and the corresponding analytical formulas were derived. Parameters were introduced to hysteretic rules to consider the pinching effect and hysteretic performance deterioration. Cyclic loading tests were used to verify the proposed method of skeleton curve, and a method was given to determine those parameters considering the pinching effect and hysteretic performance deterioration in regard to the aspect ratio. The proposed hysteretic model for rectangular bridge columns with flexure-shear mode was verified by results of shake table tests. The results show that the criterion expressed with the aspect ratio and volume ratio of transverse reinforcement can be effective to identify failure modes of reinforced concrete rectangular bridge columns. According to current codes, it is guaranteed that rectangular bridge columns will not fail in shear mode, but there is still the possibility of flexure-shear failure. The proposed method of skeleton curve can provide the results which have good agreement with trial results. It is suggested that when the aspect ratio is less than 2, the pinching effect parameter is taken as 0.5 and the hysteretic performance degradation parameter is taken as 600. When the aspect ratio is greater than 3, the pinching effect parameter is taken as 0.8 and the hysteretic performance degradation parameter is 1 000. When the aspect ratio is between 2 and 3, the pinching effect parameter and the hysteretic performance degradation parameter are linearly interpolated. Conducted on basis of the proposed hysteretic model, the results match well with results of shake table experiment on the whole, by dint of the dynamic analysis.
  • MA Hai-bin, ZHUO Wei-dong, GU Yin, NUTI C, FIORENTINO G
    China Journal of Highway and Transport. 2017, 30(12): 139-149.
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    In order to investigate the ductility demands and post-earthquake residual displacement of regular highway girder bridges under near-fault ground motions with velocity pulse, the bridges were simplified as nonlinear single degree of freedom (SDOF) systems, and a simple pulse model was used to simulate the near-fault ground motions with velocity pulses. Influences of amplitude and duration of velocity pulse, the natural period, as well as stiffness and strength degradation and pinching of the SDOF system on the ductility demand and residual displacement were systematically analyzed by dint of NSPECTRA software. The key parameters of near-fault ground motions with velocity pulse and the coupling effect of the natural period of the SDOF system were analyzed by range analyses and variance analyses of the orthogonal test design. The results show that the natural period and amplitude of velocity pulse are two main factors affecting the ductility demands and post-earthquake residual displacement of the SDOF systems, and the post-earthquake residual displacement of the SDOF systems generally increases with the increasing amplitude of velocity pulse. The duration of velocity pulse mainly affects the natural period at the peak point of the ductility demand spectrum, with less influence on the post-earthquake residual displacement. Both stiffness degradation and pinching will remarkably increase the ductility demand and post-earthquake residual displacement of the SDOF system in a short natural period, and have little influence on the SDOF system in a long natural period. The post-earthquake residual displacement increases with the development of stiffness degradation, strength degradation or pinching of the SDOF system. Besides, there is the coupling effect between the natural period of the SDOF system and the amplitude of velocity pulse, but the coupling effects of others are very small.
  • LIU Guo-huan, FENG Xiao
    China Journal of Highway and Transport. 2017, 30(12): 150-158.
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    In order to investigate the specific effect of canyon topography on the seismic wave field, a simulation approach of multi-support seismic motions was proposed and developed based on the theory of spatial variable seismic motions in a multi-layered V-shaped canyon with inhomogeneous media. The homogeneous-media canyon model was improved by introducing the layer model, and the effects of inhomogeneous media were taken into account. Firstly, the steady-state wave field was separated into two regions, namely, the open region and the enclosed region. The wave function expansion method and big-arc boundary method were adopted to obtain the analytical solution of seismic wave field in the V-shaped canyon by a train of plane SH waves. A flat-sunken coherence function model of a V-shape canyon was illuminated. Moreover, the underground power spectral density functions were deduced by a two-step transfer function method (horizontal free surface→V-shaped canyon surface→underground canyon). Then the simulation approach of spatially variable seismic motions in a multi-layer V-shaped canyon was illuminated. Finally, a visual program of multi-support seismic motions in a V-shaped canyon was developed for the simulation, whilst the rationality of calculation results was verified. The results show that there are great differences of the wave displacement amplitudes between flat terrain and canyon bottom. Influenced by the scattering wave components in the steady-state wave field of the layer interface boundary and the canyon surface boundary, the coherence of canyon effect decreases correspondingly.
  • YANG Hua-ping, QIAN Yong-jiu, LI Jing, SHAO Chang-jiang, GONG Wan-ting
    China Journal of Highway and Transport. 2017, 30(12): 159-168,195.
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    To consider the effect of velocity pulse on near-fault design response spectra, an innovative method incorporating site characteristic period Tg and pulse period Tp in the determination of the design spectra was proposed to generate normalized response spectra. The structural period was divided into three sections by taking Tg & Tp as dividing points. By adopting pulse seismic identification method proposed by Shahi and Baker, 226 groups of pulse-like ground motion records of which the seismic moments were between 5-7.9 and the fault distance between 0.07-60.9 km were selected from NGA-West2 data-base as the aggregate of near-fault pulse-like earthquake records. MATLAB was applied to conduct the dynamic calculations and statistical analysis, and to analyze the advantages and disadvantages of site consistency and data scatter of near-fault pulse-like seismic response spectra generated by Tg & Tp two-period normalization (TTN) approach as well as the existing non-periodic and single-period normalization approach, respectively. The design response spectra for bridges under near-fault pulse-like ground motions were obtained based on velocity magnification coefficient (βv) spectra by means of TTN method. The results show that, compared with response spectra generated by existing methods, βv spectra generated by TTN method present significant superiority:① The TTN βv mean spectra show excellent consistency for different site conditions, which is conducive to efficiently utilizing limited pulse-like ground motion records. ②Data of TTN βv spectra generated from earthquake records have little discreteness in all period ranges which allows better representativeness for the mean spectra. ③Variable coefficients for different site conditions show consistency and a unified coefficient is able to adjust assurance rate of mean spectra data on all regions. ④The proposed design response spectra for bridges under near-fault pulse-like ground motions based on TTN βv spectra are capable of reflecting the influence of local site conditions and velocity pulse effect on the seismic responses of structures.
  • HAN Qiang, JIA Zhen-lei, HE Wei-li, XIAO Yong-ming, JIA Jun-feng, DU Xiu-li
    China Journal of Highway and Transport. 2017, 30(12): 169-177.
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    To develop a new type of bridge seismic system of the rocking structure with the damage control characteristics and self-centering capability, the seismic design method and engineering application of the self-centering double-column rocking bridge were investigated and further discussed. Based on the force mechanism of rocking piers and the analysis model of flag-shaped hysteresis, the calculation methods of the residual displacement of the rocking pier in the depressing state, the yield state and the design limit state were proposed. And the verification formula of recovery ability was given, when the drift ratio of residual displacement was limited to less than 1%. Considering the mechanical behavior and deformation mode of the rocking piers, a direct displacement-based seismic design method for rocking bridge was put forward and the design principles and design steps were proposed. Then the design method was successfully applied to the seismic design of the Huangxu road overpass. The performance state and its index under different levels of earthquake excitation for rocking bridge were analyzed by the numerical simulation. Furthermore, the first self-centering rocking bridge project-Huangxu Road Overpass project was established, and some seismic structural details of the bridge were demonstrated. The results show that the proposed formula provides the sufficient theoretical basis for the design and calculation. The energy dissipation steel bars does not yield and has a high safety redundancy under E1 earthquake. Under E2 earthquake, with rocking piers, the stiffness of the rocking piers decreases. The increase of seismic force becomes smaller and smaller, and the structural damping function is realized effectively. The residual displacement of the pier is small and can be neglected. The self-centering function and the goals of the established seismic design are achieved.
  • MENG Qing-li
    China Journal of Highway and Transport. 2017, 30(12): 178-186.
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    In order to improve the seismic performance of RC pier columns, the design methods and effectiveness of RC pier columns seismically strengthened with precast steel fiber concrete (SFC) shell segments were investigated. Firstly, a new-type RC pier column seismic strengthening measure, that is, Precast SFC shell segment (with unbonded steel bars installed inside) wrapping the plastic hinge region of RC pier column, was developed. And its seismic strengthening design method was proposed by the theoretical deduction and analysis. Then, the RC pier column in the actual bridge composed of reinforced concrete was selected as a prototype. Based on the force-displacement hysteresis curve and skeleton curve resulted from the comparative experiments between the RC pier column model and the strengthened RC pier column model in the pseudo-static tests, the bearing capacity, the ductility and the energy dissipation capacity were compared and analyzed, and the validity of this RC pier column seismic strengthening measure was verified. Furthermore, based on the force-displacement skeleton curve resulted from the strengthened RC pier column models in the pseudo-static tests, the feasibility of the design method of RC pier column seismically strengthened with precast SFC shell segments was analyzed and discussed. The results show that the seismic strengthening measures of RC pier columns with precast SFC shell segments can obviously enhance the bearing capacity, ductility and energy dissipation capacity of RC pier column without changing their plastic hinge position. Meanwhile, according to the testing data, the feasibility of the formulas of yield moment and the maximum bending moment derived by RC pier column seismic strengthened with precast SFC shell segments, is verified. So the bearing capacity design method of RC pier column seismically strengthened by precast SFC shell segments is exemplified in some degree. The research will provide the reliable technical support for the practical engineering application of RC pier column seismically strengthened with precast SFC shell segments, so as to improve the seismic performance of RC bridge.
  • LI Yu-jing, LI Hong-nan, LI Chao
    China Journal of Highway and Transport. 2017, 30(12): 187-195.
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    Considering the economy, structural performance and other factors under the earthquake, the preference-based multi-objective optimization and decision-making method was applied to the life-cycle seismic design of beam bridge. A single-column pier was regarded as an application example, and the seismic design was to minimize the life-cycle cost and maximize the seismic capacity and the deformation index. Based on theoretical analysis and engineering judgment, the cost preference and safety preference information under the reasonable displacement ductility was used to construct corresponding value functions, progressively directing at the multi-objective optimization algorithm to the corresponding preferred solutions. The results indicate that the preference-based multi-objective optimization decision model can, in the life-cycle seismic design of bridge, meet the multiple performance requirements at various seismic hazard levels. Compared with the traditional multi-objective optimization algorithm which faces difficulties in obtaining a full approximation of the entire Pareto optimal front for large-dimensional problems and cognitive difficulty in selecting one preferred solution from all these solutions, the proposed model is available to find the global Pareto front to satisfy the corresponding preference. Furthermore, to overcome the shortcomings of repeated trial and passive verification in the classical code-compliant algorithm, the proposed model is used to actively strive the search for the more preferred solution space along the gradient of the current value function, and ultimately converge to the expected Pareto front which meets not only the needs of the lowest cost or the highest safety preference but also the rational displacement ductility.
  • DONG Hui-hui, BAI Yu-lei, HAN Qiang, DU Xiu-li
    China Journal of Highway and Transport. 2017, 30(12): 196-204.
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    Based on the concept of structural fuses and the target of reducing residual displacement, the design concept of self-centering energy dissipation brace (SCEB) applied in the structural fuse for double-column bridge structure was proposed. Firstly, a novel SCEB-self-centering buckling restrained brace was proposed. The working mechanism was clarified and the mechanical behavior of the SCEB was experimentally verified. The restoring force model of double-column bridge piers with SCEB was then established based on the mechanical performance of the SECB, and the design method of the SCEB for double-column bridge pier was proposed. The damage of the column could be reduced and the residual displacement of the structure could be effectively controlled, with the reasonable design of the SCEB for yielding and dissipating energy before the column. Numerical analyses on seismic performance of the pier with the SCEB were carried out by OpenSees FE platform to assess the viability and the availability. The results show that the proposed SCEB exhibits good self-centering abilities and moderate energy dissipation capability, and force-displacement hysteretic curves present the flag-shaped characteristic. Numerical simulations manifest that the seismic performance and energy dissipation capacity of bridge with the fuse element are better than those of the cross link beam structure, and SCEB used in double-column piers is effective. In particular, the SCEB, compared with BRB, can enhance the lateral stiffness, the protective action and energy dissipation capacity of bridge columns to mitigate the seismic damage of columns. The residual displacement of columns can be effectively reduced and eliminated by SCEB.
  • XU Xiu-li, ZHAO Yi-bo, LI Xue-hong, LIU Wei-qing, LI Zhi-jun
    China Journal of Highway and Transport. 2017, 30(12): 205-213.
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    To provide a reliable design reference for the transverse concrete block, a collision stiffness calculation method based on the Kelvin model and the Hertz model was put forward in consideration of the mass of the girder and block as well as the influence of relative velocity before the collision. The theorem of kinetic energy and conservation of momentum were considered as the theoretical basis. Considering the collision effect between the main girder and the transverse concrete block during the earthquake, the influence of the initial gap size, height and thickness on the force of the pier, the cover beam and the block was analyzed. A design principle was related to controlling the shearing force of the pier and satisfying the displacement limitation of the relative displacement between the main girder and the pier. The results show that the transverse block can effectively prevent the girder dropping. With the increasing gap size of the block, the shearing force of the pier body gently decreases. Moreover, the collision effect is weakened with the decreasing slipping distance of the transition pier. The influence of the block thickness and height on the shearing force at the pier bottom is slight, but it has a great influence on the stress of the cover beam. The stress of the cover beam decreases with the increase of the thickness of the block and the decrease of the height of the block. The maximum tensile stress of the cover beam may exceed its maximum resistance stress when the block height reaches a certain value. Furthermore, the main design parameters of the block are given as follows:the initial gap size is 0.06 m; the block height can be between 0.55 m and 0.65 m; the block thickness in the range of 0.48 m to 0.58 m. Using above mentioned parameters set for the concrete block, the maximum tensile stress at the time of collision may exceed the tensile strength of concrete to crack, while there is no damage on the concrete in the compression area. Meantime the stress of the steel bar may not exceed the yield strength of the steel, which satisfies the block capacity design requirements.
  • LI Han, YUAN Wan-cheng, TIAN Sheng-ze, DANG Xin-zhi
    China Journal of Highway and Transport. 2017, 30(12): 214-220,233.
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    In order to explore the influencing factors and laws of the vertical stiffness of High-performance Isolation Rubber Bearings (HIRBs) and obtain the simplified formulas, vertical stiffness tests were conducted on HIRBs with different configurations. The finite element models of HIRBs were established to investigate the influence of two shape factors on rubber compressive modulus of elasticity. Based on Tsai-Kelly theoretical formula and Toopchi-Nezhad modified method for compressive modulus of Fiber Reinforced Elastomeric Isolators (FREIs), variation coefficients in the Toopchi-Nezhad compressive modulus of elasticity were modified by the arithmetic solution after the parameter fitting. Hence, the formula for HIRBs was proposed. In Accordance with present HIRB configurations, the theoretical formula was simplified into a linear function between compressive modulus and the first shape factor. The results show that the compressive modulus of elasticity of HIRBs is influenced by rubber layer thickness and area of plane. Compressive modulus of HIRBs increases with the increase of the first shape factor and the decrease of the second shape factor. Finite element model of HIRB is possible to accurately simulate its vertical properties. In addition, the error between theoretical result and the result of the finite element simulation equals to only 5%, the theoretical formula of the compressive modulus of HIRBs can be applied in future research. And the simplified formula can guide the application of HIRBs in practical engineering, when the steel mesh reinforcement is 1 mm thick, 15 < S1 < 45 and 2 < S2 < 6.
  • SUN Li-min, XIE Wen, LOU Meng-lin, LIANG Fa-yun, CHEN Qing-jun, YUAN Wan-cheng
    China Journal of Highway and Transport. 2017, 30(12): 221-233.
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    To investigate the influences of the pile foundation, site soil and ground motion spatial variability on the seismic response of long-span cable-stayed bridges, a 1/70-scaled cable-stayed bridge model was designed and constructed according to a trial designed cable-stayed bridge with main span of 1 400 m. The scaled full model included superstructure, pile group foundations and model soil comprising dry sand and sieved sawdust and placed in laminar shear boxes, where the total length was 38.2 m. The travelling wave effect was realized by the time delay of the input wave arriving different supports. The scaled model was tested by the multiple shaking tables array to clarify the mechanism associated with the seismic response of the super long-span cable-stayed bridge under uniform and non-uniform excitations in the longitudinal and transverse directions, respectively. The results show that the travelling wave effects have very complex influences on the seismic response of the long-span cable-stayed bridge. There are approximately 50% and 40% increments in the longitudinal acceleration response at the tower top and the vertical acceleration response of the girder under non-uniform excitations, compared with those under uniform excitations in the longitudinal direction. Whereas there are approximately 15% and 50% reductions in the transverse acceleration response at the tower top and the girder under non-uniform excitations, compared with those under uniform excitations in the transverse direction. The vertical relative displacement of the girder under non-uniform excitations is approximately 40% larger than that of the girder under uniform excitations in the longitudinal direction, while the transverse relative displacement of the girder under non-uniform excitations is approximately 20% smaller than that of the girder under uniform excitations in the transverse direction. Furthermore, the travelling wave effects also have inconsistent influences on the seismic response of various components. There are approximately 50%, 40% and 60% reductions in the longitudinal relative displacement at the tower top, between the tower and girder, and the pier top under non-uniform excitations compared with those under uniform excitations. However, there is approximately 40% increment in the vertical displacement of the girder under non-uniform excitations, compared with that under uniform excitations in the longitudinal direction. In addition, the pile-soil-structure interaction has an obviously adverse influence on the towers and piers so as to make the acceleration response at the tower bases and pier bases amplify approximately twice and 1.1-4.0 times, respectively. Consequently, it is suggested that the travelling wave effects and pile-soil-structure interaction effects should be considered when conducting seismic analysis of long span cable-stayed bridges, especially considering adverse influences on the seismic response of long-span cable-stayed bridges.
  • ZHANG Rui, MENG Qing-li, HE Wei, NIWA Junichiro
    China Journal of Highway and Transport. 2017, 30(12): 234-241,249.
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    To investigate the shear reinforcing effect of stirrups in the steel reinforced engineered cementitious composite (ECC, R/ECC) beams, in allusion to the steel reinforced concrete (RC) structural member with shear failure, four-point loading tests were conducted on both RC and ECC beams by considering the effect of stirrup ratios. The tensile mechanical properties of polypropylene fiber reinforced engineered cementitious composites (PP-ECC) were firstly investigated by conducting uniaxial tensile tests. Based on the results, a total of 7 beams, classifying into 2 categories, namely, 5 steel reinforced PP-ECC and 2 RC beams, were designed and constructed. All beams were tested by four-point loading tests. In addition, the shear cracking behavior of 5 PP-ECC beams were carefully observed and measured during the loading, and the effect of stirrup ratio on the shear cracking behavior was analyzed. Through the modified truss model, the shear capacities of 5 PP-ECC beams were investigated by considering the effect of stirrup ratio. The experimental results show that PP-ECC exhibiting pseudo strain-hardening behavior and multiple fine cracking has tensile yield and tensile strength which is no less than 2 MPa and 3 MPa, respectively, and its tensile strain capacity is greater than 2.5%. ECC beams are with good ductility, whose shear capacity gradually increases with the increase of stirrup ratio. Under the same stirrup ratio, the shear capacity of R/ECC beam is larger than that of RC, and the R/ECC beam without stirrups shows twice shear capacity of RC beam. In addition, the shear carried by PP-ECC decreases with the increase of the stirrup ratio. The reason is that the higher stirrup ratio restricts the development of shear cracks, and the sliding in the critical shear cracks increases, thus decreasing the bridging effect of fibers. However, the current design and specification does not take the effect of shear sliding into considerations, which may result in overestimation on shear capacity of R/ECC beams.
  • JIA Jun-feng, ZHAO Jian-yu, ZHANG Qiang, HAN Qiang, DU Xiu-li, QI Lu-kuan
    China Journal of Highway and Transport. 2017, 30(12): 242-249.
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    To develop environment-friendly, highly-efficient precast bridge structures suitable for moderate-to-high seismic regions, two novel precast segmental CFST bridge piers with bolted connections were proposed. The quasi-static lateral cyclic loading test on the aforementioned precast segmental CFST bridge piers with and without axial prestress was carried out to investigate and analyze the nonlinear behavior, including the resilience-displacement hysteretic behavior, unloading stiffness, prestress loss in tendons, joint opening. The structural deformation and damage process of precast segmental CFST bridge piers under the cyclic loading was briefly described. The results show that the precast segmental CFST bridge piers with bolted connections can provide the favorable lateral bearing capacity, the excellent energy dissipation capacity, plump hysteretic curves and the appropriate ductility. The self-resetting capability of precast segmental CFST bridge piers can be improved by axially post-tensioned unbounded prestress. Compared with the opening situation at the bottom of traditional assembled piers, the uniform distribution of joint opening between adjacent segments will be attained by the reasonable detail design of connecting pipes to make the best of the segmental strength. The axial prestress tension extends linearly with the increase of the horizontal loading displacement drift. The adequate lateral strength of the precast segmental CFST bridge piers with bolted connections is revealed with horizontal displacement drift of 7.7%, and the prestress loss in strands is about 20% of the initial tension force after removing the lateral loading action. The results will provide references for the structural design and engineering practice of precast segmental CFST bridge piers, with a positive meaning for R & D of accelerated bridge construction.
  • ZHANG Shi-bo, LIU Chun-guang
    China Journal of Highway and Transport. 2017, 30(12): 250-257.
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    In allusion to the numerical simulation technical and dynamic model obstacle in the dynamic response of the cable-stayed bridge tower foundation under the complex environment loading, a trial design of a cable-stayed bridge pylon foundation was employed as research background. First, a 1:100 scale dynamic test model of the pile group cable-stayed bridge tower foundation was designed according to the laws of similarity for elasticity and gravity and methods of equivalent transformation. Second, the loading systems of the sine wave and white noise under a dry environment as well as seismic waves, incident waves and current which were inputted individually or jointly with water state were designed. Finally, the experiment was conducted to analyze the dynamic response of the pile group cable-stayed bridge tower foundation subjected to complex environment loading based on the Earthquake, Wave and Current Joint Simulation System at Dalian University of Technology. The variation trend of dynamic hydraulic pressure, dynamic response characteristics and failure mechanism of the pile group cable-stayed bridge tower foundation under the complex environment loading were analyzed. The results show that the maximum acceleration response occurs at the pile-cap, and higher strain occurs at both the top of pile group and the bottom of pylon, when the cable-stayed bridge is under the random loading actions. The earthquake has a great influence on the hydrodynamic pressure, but wave and current have less influence on the hydrodynamic pressure. The dynamic response of the top of pylon is related with the type of the input earthquake wave. Under the joint action of the earthquake and wave, the acceleration of the top of the pylon contributed by the earthquake was strong enough that the influence of the wave on the acceleration of the top of the pylon can be neglected. The test results provide references for the revised seismic design code of long-span cable-stayed bridges with deep water foundation.
  • BU Zhan-yu, ZHANG Xu, YE Han-hui, XI Kang
    China Journal of Highway and Transport. 2017, 30(12): 258-267.
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    To provide reference for the seismic calculation of precast segmental bridge columns (PSBC), in the light of two connection manners with unbounded prestressing tendon or prestressing tendon plus energy dissipation (ED) bar employed in typical PSBCs, the multi-joint rotation analytical pushover (MRAP) calculation process of PSBC was deduced, considering the nonlinear constitutive model of concrete, ED bar and prestressing tendon, respectively. The flexural moment capacity and the corresponding column tip lateral force were determined based on critical section moment-curvature analysis. Then the flexural moment and curvature on every joint were derived, whilst the column tip displacement was calculated. Two quasi-static tests of PSBC with two kinds of joint connections were conducted. The MRAP simulation results were compared with quasi-static test results. The lateral resistant force-drift curve, joint opening, prestressing tendon stress, and column rotation variation with drift, the contribution of every mechanism to column tip displacement, and the concrete strain near the joint were analyzed. The results show the lateral resistant force calculation results by MRAP method are nearly the same with those by single-joint rotation method. But the displacement calculation results in view of MRAP are larger than those by single-joint rotation method. The calculation precision of MRAP is better than that of single-joint rotation method. The calculation results of joint opening, prestressing tendon stress, and joint rotation by MRAP is consistent with test results. The column tip displacement is mainly provided by shear displacement and global flexural displacement at the beginning. Subsequently, with the increasing of column tip displacement, the contribution of column base joint rotation is dominant. The tendency of concrete strain at joint gradually decreases with the increasing of height is validated by test results of column concrete axial strain. The concrete strain on joints is much larger than that of column axial strain.
  • LIANG Fa-yun, JIA Ya-jie, SUN Li-min, XIE Wen, CHEN Hai-bing
    China Journal of Highway and Transport. 2017, 30(12): 268-279.
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    To investigate the seismic response of pile groups supporting long-span cable-stayed bridge under uniform excitations, a series of shaking table tests were carried out considering the seismic soil-pile-structure interaction (SSPSI) based on a 1/70 scaled model of an assumed prototype (a cable-stayed bridge with the length of 2 672 m and a main span of 1 400 m). The pylons and piers were fabricated of micro-concrete and iron wire. The piles and pile-caps were made of C40 concrete and rebar with the diameter of 6mm. The natural soil was simulated by sand and sawdust with the mass ratio of 3:1. The scaled model included 8 groups of pile foundation supporting transition piers, auxiliary piers and pylons, respectively. Four types of seismic waves, namely, artificial seismic wave Acce100, natural waves El Centro, Mexico City and Chi-Chi, were employed to investigate the impact of input waves with different predominant frequencies on the seismic response of the pile group foundation. The seismic response of pile group foundation supporting piers and pylons, including pile accelerations, displacements and moments, were highlighted. The results show that on account of the different vibration characteristics of pile group supporting piers or pylons, the same ground motions are transmitted differently to the bottom of transition piers, auxiliary piers and pylons, by dint of the pile group foundation. Seismic waves are changed differently by pile groups at different locations, and the excitations input to superstructure from the bottom of piers or pylons are different. With the peak acceleration of input waves growing, acceleration and relative displacement at pile head for pile groups supporting auxiliary piers and pylons increase, but amplification ratios of peak acceleration decrease. Among the four seismic waves, relative displacement and bending moments at pile head of each pile group caused by Chi-Chi are the largest. The relative displacement and amplification ratios of peak acceleration at the head of pile groups supporting transition piers are larger than that of pile groups supporting auxiliary piers under the Mexico City excitation. However, the opposite results will be acquired under the other 3 types of excitations.
  • SHANG Yu, YE Ai-jun, WANG Xiao-wei
    China Journal of Highway and Transport. 2017, 30(12): 280-289.
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    To investigate the effect of scouring on the seismic response of free field and the bridge with pile foundation, a shake table test on pile supported bridge was designed and conducted. A laminar shear box was used in the test, filled with uniform layers of sand to simulate the site. The relative density of sand was about 50%. The specimen was a single pier structure supported by a 2 by 2 pile group. A 4-ton steel block was fixed on the top of pier to simulate the superstructure, resulting in a primary period of 0.5 s. There were three test cases including the free field test, small scour depth specimen and large scour depth specimen with a range of scour depth from 0 to 8 times of pile diameters. In the tests, the white noise input was deployed to get dynamic properties of soil and structure, whilst the Chi-Chi earthquake ground motion record was used to investigate the seismic response of soil and structure. The data got from accelerometers, displacement transducers and strain gauges, were used to analyze the dynamic properties, acceleration time history of soil and structure and curvature distribution of structure. The results show that under the scouring condition, the soil and structure are the two key factors which would control seismic behavior of pile supported bridge. Soil layers have an amplification effect on the earthquake input comes from bedrock. With the increase of scour depth, the critical section of bridges with pile foundation transfers from pier to pile foundation. In addition, the first yielding region on the pile transfers from the middle part of pile to the top of pile.
  • JIA Jun-feng, ZHAO Jian-yu, GUO Yang, OU Jin-ping
    China Journal of Highway and Transport. 2017, 30(12): 290-298.
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    To develop a new type of three-dimensional (3D) isolator proposed by authors and investigate seismic responses and 3D isolation effect of 3D isolated continuous girder bridges under different seismic intensities and characteristics, a 1/25 scaled three-span continuous girder bridge with 3D isolator bearing (3DIB) and a single-span girder bridge with the common natural rubber bearing (NRB) only for horizontal isolation were designed and manufactured. The 3DIB and NRB were designed and selected for the bridge model test. On this basis, the horizontal and vertical seismic simulation shaking table tests were respectively carried out on the three-span and single-span isolated continuous girder bridge models. The results show that the developed 3D isolation bearing takes effect safely and effectively with no damage under almost all seismic excitations after the test. There is no damage on three-dimensional isolation bearing after the test. Under the horizontal earthquake action, both 3DIB and NRB reveal favorable horizontal isolation effect with 50%-80% for horizontal acceleration of main girders. The horizontal isolation effect of 3DIB with lead-core laminated rubber component is obviously better than that of NRB under near-fault pulse-like ground motions. Under the vertical seismic action, the peak vertical acceleration of the single-span girder isolated by NRB may obviously increase. The maximum acceleration may be double that of the original one. The amplitude may be enlarged in some time although the peak value is not amplified in some excitations. The peak vertical acceleration of the continuous girder with 3DIB will decrease by 30%, even up to 50%, and there is basically no local amplification in some time. The 3D isolated bridge shows satisfactory isolation effect under horizontal and vertical seismic excitations, which provides the valuable basis for 3D isolation technology applied in the bridge engineering.