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15 April 2014, Volume 33 Issue 2 Previous Issue    Next Issue

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FailuRe Mechanism of MasonRy ARch BRidge by Analysis Method Hong Hua，Liu Shanhong，Ma Dengyang 2014, 33(2): 1-4.  DOI: 10.3969/j.issn.1674-0696.2014.02.01 Abstract ( )   PDF (207KB) ( )   Deformation or local cracking appears in masonry arch bridge under the excessive external loadings to adjust its own constraints． The masonry arch bridge disease was studied based on Heyman analysis method，D.K.McNeely analysis method and Qian Lingxi analysis method.Three hinge failure mechanism and qualitative analysis mechanism of the pressure line were presented to determine the damage of masonry arch bridge． References | Related Articles | Metrics

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Development of Cable Inspection System ?ased on Image Processing Liu Chaotao, Du Zixue, Wu Wei, Xiang Zhongfu 2014, 33(2): 5-9.  DOI: 10.3969/j.issn.1674-0696.2014.02.02 Abstract ( )   PDF (418KB) ( )   A stayed cable health inspection system based on the image acquisition and processing was developed , which con sisted of robot , hosl computer , cameras and image acquisition syslem. The robot was driven with single motor and could automatically climb cables of various diameters. Omni-directional pictures of the cables were taken by the robot , and the de fects and mars were identified through the automatical recognition of the cable image. The steps of image recognition including image de-noising , image enhancement , image segmentation and feature extraclion , and lhe defecls and mars were iden tified from the features of the grayscale distributions and energy distributions in grey level histogram. References | Related Articles | Metrics

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Primary Analysis of The Additional Moment of Center Axis For The Whole Mechanics of Column with Reinforced around The Cross Section Wang Jun，Liu Shaoqian，Su Wenming，Zheng Gang 2014, 33(2): 10-14.  DOI: 10.3969/j.issn.1674-0696.2014.02.03 Abstract ( )   PDF (354KB) ( )   According to the theory of the basic mechanics. the mechanical mode of the concrete column with reinforced around the section was predigested. The force balance equation and torque-equilibrium equation were presented by derivation. The deviation of cenler axis in the crazing cross-section of the bridge pier in the course of earthquake was analyzed The conception of the additional moment of center axis was adopted , and the cause of the additional moment of center axis and its influence on the mechanics and the whole stiffness of column were discussed. The results show that , in a certain sense , the additional moment of center axis could offset the horizontal defoτmation of column with reinforced around the cross-section; and could restrain the cross-section to crack and defer the degradation of stiffness. And it is recommended that the additional moment of center axis should be considered in the seismic analysis of the stmcture. References | Related Articles | Metrics

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Damage Mechanism of Simply Supported Beam Bridges' Pier and Girder in Wenchuan Earthquake Xiao Xuhong 2014, 33(2): 15-20.  DOI: 10.3969/j.issn.1674-0696.2014.02.04 Abstract ( )   PDF (432KB) ( )   Study on damage mechanism of bridge is the important procedure which turns seismic damage investigation results into a practical technology. Some damage features of simply supported beam bridges which differ from the features in other earthquakes are shown in Wenchuan earthquake. The damage mechanism of pier and girder was simulated by FEM analysis and seismic table test. The results show that the seismic action of girder released by relative sliding between girder and bearing is why the damage of pier is reduced in Wenchuan earthquake. The displacement of girder is coordinated by continuous pavement , and the longitudinal displac&lnent is restrained by abutment , which reduces the risk of girder fell down. A complete seismic resistance system is formed by girder, pier, bearings , abutment , continuous pavement in simply supported beam bridges; the seismic action of girder is released and the risk of girder fell down is reduced by the system. References | Related Articles | Metrics

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VibRation Analysis of BRidge undeR TRains ConsideRing TRansient Jump of Wheel Yang Hongyin，Zhang Hailong，Chen Zhijun，Huang Wen 2014, 33(2): 21-25.  DOI: 10.3969/j.issn.1674-0696.2014.02.05 Abstract ( )   PDF (468KB) ( )   The non-linear Hertz contact theory was adopted and then linearized，and a new vehicle-bridge interaction element considering the transient jump of wheel was derived，which solved the deficiency of the no-jump assumption in the traditional analysis． The dynamic equations of the interaction system were then formulated by means of the“set-in-right-position”rule for formulating matrices，and the combination method and the solution procedure were also presented． Finally the corresponding calculation program was coded，and the proposed interaction element was adopted to analyze an established railway bridge． The results demonstrate that the dynamic acceleration response of the bridge significantly increase and the results of moving loads model are safer under the vehicle-bridge resonance． The abrupt irregularity causes strongly high frequency vibration and makes the dynamic acceleration response of bridge remarkably increase． When there is no jump of the wheel， the result from the proposed method is consistent to the traditional one． But when the jump happens，the proposed method also yields a true result while the traditional one can’t，and the transient jump of wheel has been accurately simulated by the proposed method． The model considering transient jump of wheel should be adopted to analyze the vehicle-bridge interaction and the track maintenance and the deformation control of bridge should be paid more attention． References | Related Articles | Metrics

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Crack Width Monitoring of Concrete Structures Based on Smart Film Zhang Benniu，Fan Zhonghua，Huang Rui，Zhang Xu，Yang Guang，Li Xingxing，Wu Tao 2014, 33(2): 26-29.  DOI: 10.3969/j.issn.1674-0696.2014.02.06 Abstract ( )   PDF (315KB) ( )   Smart film monitoring method has the capability of monitoring the important features of concrete structures effectively， such as occurrence，location，shape，length and development of initial crack． Aiming to monitor the crack width of concrete structures，the improved smart film adopted several groups of bunched magnetic wires which were horizontally placed． Each group of bunched magnetic wires was composed by a few of magnetic wires with different diameters，and each magnetic wire had different ultimate tensile strain． Therefore，the direct proportion between the ultimate tensile strain of magnetic wires and the crack width of structures was verified by the theoretical derivation and experiments． And the crack width can be indirectly calculated by the ultimate tensile strain of magnetic wires． References | Related Articles | Metrics

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Large Span Bias Weak Surrounding Rock Double-Arch Tunnel Construction Process Gao Feng ，Xue Dianli 2014, 33(2): 30-34.  DOI: 10.3969/j.issn.1674-0696.2014.02.07 Abstract ( )   PDF (348KB) ( )   The process of the construction of the transitional joint arch tunnel of Ziyin Tunnel in Zunyi was simulated by ANSYS FEM program. The stress states of sUITounding rock , ground settlement and the change of intemal forces of tunnel support structure during each period of construction were analyzed by the analysis of 3 excavation conditions. Through the comparative analysis and the monitoring and measurement data in the field construction , it is revealed that different excavation sequences have different effects on the tunnel stlucture in biased state. References | Related Articles | Metrics

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Influence of Bridge Pile Construction Vibration on Adjacent Buried Pipeline She Yanhua, Su Huayou 2014, 33(2): 35-39.  DOI: 10.3969/j.issn.1674-0696.2014.02.08 Abstract ( )   PDF (379KB) ( )   Through developing field micro-seismic trial , the characteristics of vibration attenuation of bridge pile construction and sphere of inf1uence were analyzed to assess their impact on the buried pipeline nearby. It is concluded that the amplitude of vibration energy have been enlarged with the presence of the pipeline; it should make the smface peak velocity above the pipeline as the main control index in routine vibration monitoring of pile foundation construction adjacent to buried pipeline. By analyzing positioning of impacting vibration source , the rupture area of rock and soil around the pipeline caused by the vibration was determined , and the conesponding security ll1easures for pipeline protection was proposed. It provides a new trial ll1ethod of control technology for pile foundation construction. References | Related Articles | Metrics

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Application of Transient Electromagnetic Method in Subsidence Area of Collapsible Loess: Case Study of Chang-Yan Separate Overpass Jiang Bo，Wang Zhirong，Jia Yakun，Zhang Limin 2014, 33(2): 40-43.  DOI: 10.3969/j.issn.1674-0696.2014.02.09 Abstract ( )   PDF (318KB) ( )   For the specialties of subsidence problems of collapsible loess in West Henan，the transient electromagnetic method was applied to explore the resistivity response characteristics of the non-layered system in loess areas，including the chasm，fracture and collapse body of water． A program which could make a direct and dynamic query of soil moisture according to a visible resistivity ρ value was designed to realize the quick conversion of soil moisture information from the electric information． According to the case studies，10 percent of water content was the criterion of judging the collapsible area． The geophysical interpretation and prediction methods were proposed to deal with loess collapsibility problems in West Henan，and the exploration engineering was used to verify the effect of detection，which is a good example for the similar complex project． References | Related Articles | Metrics

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Influence of Interlayer Contact on the Mechanics Behavior of Semi-rigid Asphalt Pavement Li Xing , Liu Zhifang , Song Xiaoyan 2014, 33(2): 44-48.  DOI: 10.3969/j.issn.1674-0696.2014.02.10 Abstract ( )   PDF (366KB) ( )   Based on the typical multilayer elastic layered system , the asphalt pavement structure was divided into top surface layer , middle surface layer， bottom surface layer , semi-rigid base and soil base. Considering the contact between layers of the structure , a three dimensional finite element interlayer-contact model was established and the contrast analysis with the interlayer-continuous model was conducted by ABAQUS. In two different finite element models , the deflection values of the pavement with the vehicle load , the max principal stress of asphalt surface and semi-rigid base , the min principal strain of top soil base and the max shearing stress of the structure layer were presented. The results show that the designed value for the thickness of semi-rigid pavement based on interlayer-continuous model is smalL lt causes damages in the early operation stage of asphalt pavement. And the interlayer-contact model is in line with the real working state of the pavement layer bet ter. The interlayer-continuous model is suggested to use in the designing of thickness for semi-rigid pavement References | Related Articles | Metrics

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Impacts of Base Parameters on Mechanical Properties of Cement Pavement Considering Interlayer Contact Zhang Yancong , Zhao Duijia , Liu Shaowen , Shen lunmin 2014, 33(2): 49-52.  DOI: 10.3969/j.issn.1674-0696.2014.02.11