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15 August 2013, Volume 32 Issue 4 Previous Issue    Next Issue

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Vertical Vehicle-Bridge Coupling Dynamic Analysis on Highway-Ｒailway Cable-Stayed Bridge Xie Bingmin，Xiang Zhongfu，Wang Xiaosong，Wang Shaohuai 2013, 32(4): 551-554.  DOI: 10.3969 /j.issn.1674-0696.2013.04.01 Abstract ( )   PDF (848KB) ( )   Taking a certain highway-railway cable-stayed bridge as the research object，the FEM model is established to analyze the natural frequency and mode shape characteristics，through the space bar FEM method and grillage method based on ANSYS． The coupling vibration responses of vehicle-bridge system under a running train are also calculated． Ｒesults indicate that the dynamic response between vehicle and bridge got by the proposed method is consistent with the measured results at home and abroad． At the same time，the vertical comfort and safety indicators when the vehicle is running meet the regulatory requirements． References | Related Articles | Metrics

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Finite Element Model Updating of Single Pylon Cable-Stayed Bridges Based on ＲBF-ANN Shan Deshan，Ding Dehao，Li Qiao，Huang Zhen 2013, 32(4): 555-559.  DOI: 10.3969 /j.issn.1674-0696.2013.04.02 Abstract ( )   PDF (363KB) ( )   In order to obtain the contemporary state for the cable replacement project of one certain existing single pylon cable-stayed bridge with double cable plane，a new combined method for finite element model updating is proposed． In the light of the parameterized model updating theory，the relative sensitivities of the calculated design parameters are analyzed to determine the will be modified parameters． Substructure method is introduced in the model updating process for meet the requirement of the parameter’s discreteness，and the calculated parameters in each substructure is regard as invariables． The radial basis function neural network ( ＲBF) is adopted as the optimization algorithm of model updating． Combination the substructure method and ＲBF，the intrinsic“inverse problem”of finite element model updating is transformed as the“forward problem”． The substructure partition，ＲBF neural network construction and its input and output parameters determination are discussed as well． A certain existing single pylon cable-stayed bridge is taken as the case study to verify the proposed combined model updating algorithm． The result shows that the discrepancy between the calculated value and measured valued decrease dramatically before and after the finite element model updating． References | Related Articles | Metrics

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Application of Vehicle-Bridge Coupling Vibrations Theory in the Study of Bridge Surface Ｒoughness Yi Jinsheng，Gu Anbang，Wang Xiaosong 2013, 32(4): 560-563.  DOI: 10.3969 /j.issn.1674-0696.2013.04.03 Abstract ( )   PDF (225KB) ( )   The vehicle-bridge system are considered as two separate subsystems，and the vibration equilibrium functions for double axis vehicle model and bridge are derived with the application of d’Alembert principle． And then the separate iteration method is applied in the numerical solution of vehicle-bridge coupling vibration problem． In consideration of NEWMAＲK numerical calculation principals，computational procedures for vehicle-bridge coupling vibration are compiled by use of MATLAB． Furthermore，the accuracy of this program is verified． The influence of the deck conditions and vehicle speed on vehicle-bridge system is discussed on the basis of this program． It demonstrates that the solution is accurate and the influence of the deck conditions on vehicle-bridge vibration is significant; the influence of the vehicle speed on bridge vibration depends on the force frequency caused by vehicle on the bridge． References | Related Articles | Metrics

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FEM Calculation of Space Timoshenko Beam of Large Deflection Liu Xiaohui，Wang Jialin，Yan Bo 2013, 32(4): 564-568.  DOI: 10.3969 /j.issn.1674-0696.2013.04.04 Abstract ( )   PDF (312KB) ( )   A variation principle for Timoshenko beams of large deflection with geometrical non-linearity is presented． And the space beam element stiffness matrix of large deflection can be deduced from this variation principle，considering the effect of the shear deformation． To improve the computational precision and efficiency for the large displacement and rotation of beam，a finite element method based on the moment-curvature relationship of beam section is presented． The method calculated by node coordinates of the beam element is applied to calculate the internal nodal forces． A nonlinear finite element code is then developed which considers the effects of large rotations，large displacements and shear deformations． Numerical examples are provided in order to verify the feasibility and effectivity of the presented method． References | Related Articles | Metrics

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Casting Length of Cast-in-Place ＲC Arch Ｒib in Arch Centering Zhou Shuixing，Deng Xiang 2013, 32(4): 569-572.  DOI: 10.3969 /j.issn.1674-0696.2013.04.05 Abstract ( )   PDF (390KB) ( )   The deformation law of arch centering is analyzed in the process of pouring arch concrete． A new method is proposed to determine the concrete cast-in-situ section lengths and corresponding formulas based on deformation proportion of arch centering are deduced． When the stiffness of earlier constructed concrete is ignored，all concrete is cast at the same loop，and the deflection of arch centering is a constant． According to influence line of arch centering deflection，a program which is used to calculate the cast length and arch centering deformation is developed by APDL language of ANSYS． This program could automatically calculate every casting length of arch concrete based on the assigned deformation condition． A numerical result shows that deformation proportion caused by each segment of box concrete should be controlled in range of 0． 5 ～ 0． 6，when the arch centering deformation scale is taken as the target． References | Related Articles | Metrics

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Experimental Ｒesearch and Application of the New Welding Stirrup Liao Xiufeng，Wei Qike，Dong Mengneng，Wu Bo，Li Zhineng 2013, 32(4): 573-576.  DOI: 10.3969 /j.issn.1674-0696.2013.04.06 Abstract ( )   PDF (293KB) ( )   Compared with the traditional composite hook stirrup，the new welding stirrup saves the material of hook and the repeated part． Further more． the new welding stirrups are manufactured by the factories that assure the dimensional accuracy and quality of the stirrup． From the two aspects of the energy-saving，emission reduction and mitigation of labor shortage，economic and social benefits are very significant． The mechanical behavior and seismic performance of the new welding stirrup have been examined by the low cyclic loading experiment and axial compression test． The result illustrates the advantage of the new welding stirrup in its applicability and anit-seismic performance． References | Related Articles | Metrics

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Correcting on Bump Quality Impact on Filed Test of Natural Vibration Frequency Shi Shangwei，Xu Xuxu，Xu Peng 2013, 32(4): 577-580.  DOI: 10.3969 /j.issn.1674-0696.2013.04.07 Abstract ( )   PDF (200KB) ( )   Through the analysis on three-equal-span continuous beam jump car test，it is found that the additional quality of test truck can affect the measured bridge natural frequencies． Ｒayleigh method is used to assume the shape function of bump test; correction coefficient λ is introduced and a modified formula for the measured natural vibration frequency of three-equal-span continuous beam． The case study shows that the error of field measuring frequency reduces by 27% after correction than that before correction． References | Related Articles | Metrics

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Quick Deflection Monitoring System of Gaojiahuayuan Bridge Zhang Benniu，Cui Hongmei，Shi Lingli 2013, 32(4): 581-584.  DOI: 10.3969 /j.issn.1674-0696.2013.04.08 Abstract ( )   PDF (354KB) ( )   Through the design and installment of a quick deflection monitoring system on Gaojiahuayuan Bridge，the monitoring data after fire disaster in box beam are analyzed． Since the system performs a long term deflection monitoring for the deflection change of the bridge in a short time after fire disaster，the monitoring data could guide the research on the structure deformation of the bridge after the fire． References | Related Articles | Metrics

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Weight Determination Method of Bridge Static Parameter Monitoring Section Based on Damage Sensitivity Shi Zengchao，Wu Xiaoguang，Wang Fuyi 2013, 32(4): 585-588.  DOI: 10.3969 /j.issn.1674-0696.2013.04.09 Abstract ( )   PDF (249KB) ( )   The static measurements such as structure displacement and stress are important factors to do the safety assessment of bridge structure by the synthesized assessment method． As weight values of sections are depended on experts’judgment by giving grades or filling judgment matrix forms，this method has more subjectivity． The damage sensitivity degree of monitoring parameters at different sections of bridge is analyzed，and a damage sensitivity factor S of each monitoring section is constructed． And then the weight value is obtained by normalizing the weight eigenvectors composed by S． The proposed method effectively avoids the subjectivity of weight determination． References | Related Articles | Metrics

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Evaluation of Hazardous Materials Transportation on Super-Large Bridge Based on Set Pair Theory and Variable Weight Principle Qi Yuchao，Zhang Weigang，Lu Jian 2013, 32(4): 589-593.  DOI: 10.3969 /j.issn.1674-0696.2013.04.10 Abstract ( )   PDF (224KB) ( )   The evaluation of hazardous materials transportation on super large bridge can effectively prevent and reduce the accidents． Based on the set pair theory and variable weight principle，the hazardous materials transportation in the condition of severe weather and emergency in the Yangtze Ｒiver Delta is analyzed，and the key influence factors of operational safety are also proposed． The influence factors are analyzed respectively by the set pair theory from the perspectives of sameness，difference and reverse． Combining the set pair theory with the penalty-incentive principle of target weight，a varying weight evaluation model of the hazardous materials transportation on super large bridge is established and the maximum connection is taken as the principle to judge the security of the project． Through the case study，it is indicated that the application of this evaluation method is effective，which can offer reference for the bridge operator． References | Related Articles | Metrics

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Longitudinal Slope at Super-Elevation Sections of S Curve Considering Flow Path Length Zhang Zhuo，Gao Jianping 2013, 32(4): 594-596.  DOI: 10.3969 /j.issn.1674-0696.2013.04.11 Abstract ( )   PDF (174KB) ( )   It is easy to have water at super-elevation section of S curve in rain，which affects the traffic safety． According to the difference of super-elevation gradient direction，the gradient sections are divided into the same change direction and the opposite of cross slope． The calculation models for flow path length of super-elevation section are established by dynamics and FDM． Considering the vehicle in hydroplaning danger state，the control length of flow path is obtained． Taking S curve of highway arch as the research object，flow path length of transition section whose super-elevation value is from -2% to 2% is analyzed，with 3 different types of lane numbers and 7 different types of longitudinal slopes． The results show that when longitudinal slope is increased from 0． 5% to 6% ，the average flow path length increases 2． 83 times; the larger longitudinal slope，the longer of flow path length; when longitudinal slope is greater than 4% ，the prescribed values of different lanes all exceed． Taking the flow path length as the control index，the proposed maximum longitudinal slope values at super-elevation section of S curve with different lanes are put forward． References | Related Articles | Metrics

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Influence Factors of Frost-Salt Ｒesistance of Cement Concrete Zhang Hui，Pan Yonqiang，Zhang Jian，Zhu Lei 2013, 32(4): 597-600.  DOI: 10.3969 /j.issn.1674-0696.2013.04.12 Abstract ( )   PDF (278KB) ( )   The influence factors on frost-salt resistance of cement concrete including air void systems，surface conditions and loads are studied by indoor test． The results show that the spacing factor has more impact on frost-salt resistance of concrete than air content does． The frost-salt resistance of concrete is not so sensitive if the air content is beyond 6% or the spacing factor is less than 0． 18mm． Ｒesults also indicate that different surface properties have influence on frost-salt resistance of concrete． Improper operation and surface weeping of concrete will lower the frost-salt resistance of cement concrete by lowering the strength of concrete and degrading the air void structural parameters． And the coupling interaction of load and freezedeicer scaling cycle will greatly accelerate the frost-salt scaling of concrete． And the general laboratory tests may overrate the frost-salt resistance of concrete in practical engineering． References | Related Articles | Metrics

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Effects of Compound Curing Agent on Structure and Properties of Epoxy-Asphalt Zhou Wei,Zhao Hui,Wen Jun,Cai Fangchang,Jiang Tao 2013, 32(4): 601-605.  DOI: 10.3969 /j.issn.1674-0696.2013.04.13 Abstract ( )   PDF (476KB) ( )   Methyl-tetrahydrophthalic anhydride ( MeTHPA) or tung oil anhydride ( TOA) is added in decanedioic acid，which is taken as the epoxy-asphalt curing agent． Tensile strength，penetration，DSC，DMTA，torn section microscopy photos and SEM analysis are used to investigate the mechanical properties，thermodynamic behavior，and micro-structure of epoxy-asphalt curing systems under different curing agents． The results show that: the compound curing agent can make strength and surface hardness of the epoxy-asphalt curing system effectively improved，the induction period of the curing reaction shorten，and the curing reaction mechanism turn to one-step reaction from two-step reaction; the compound curing agent can make the glass transition temperature of asphalt phase and epoxy phase simultaneously increased，and high-temperature damping performance also improved，but the particle size of asphalt dispersed in epoxy resin become uneven，and the curing system become semi-brittle from toughness． Compared with compound TOA，the effects of MeTHPA in decanedioic acid are more obvious． References | Related Articles | Metrics

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Ｒesearch on Fatigue Properties of Ｒeclaimed Asphalt Pavement Dong Lingyun，He Zhaoyi，Huang Gang，Wang Guowei，Hou Jun 2013, 32(4): 606-609.  DOI: 10.3969 /j.issn.1674-0696.2013.04.14 Abstract ( )   PDF (319KB) ( )   Aiming at ＲAP ( reclaimed asphalt pavement) of Yu-Chang freeway，the indirect tensile fatigue tests are carried out between a fresh asphalt mixture of AC-16 and the reclaimed AC-16 with ＲAP mixing amount 10，30，and 50 respectively，before and after the long-term aging． The fatigue life ratio Nf( k / n) and fatigue life loss ratio F ( k) are introduced to systematically analyze the variation of the fatigue properties of the reclaimed asphalt mixture． Test results show that: with the increase of ＲAP amount，the reclaimed asphalt mixture fatigue life ratio decreases; meanwhile，the age of fatigue life ratio of the reclaimed asphalt mixture is less than that before aging，and the fatigue life loss ratio increases． References | Related Articles | Metrics

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Two-Stage Design Method for the Evotherm Warm-Mix Asphalt Mixtures Li Zhengzhong，Wei Ｒuxi，Song Xiaoyan，Ma Tao 2013, 32(4): 610-613.  DOI: 10.3969 /j.issn.1674-0696.2013.04.15 Abstract ( )   PDF (300KB) ( )   By analyzing the principle of Evotherm warm-mix technology and the current situation of design method for warmmix asphalt mixtures，it is the first time to propose the two-stage design method． Based on two-parameter system including asphalt content and test temperature，the components of Evotherm warm-mix asphalt mixtures are optimized，considering the design data of hot-mix asphalt mixtures． The control temperature is determined according that the volume parameters of specimen are basically equal． Based on the two-stage design method，GTM molding method is used to design Evotherm warmmix SBS-modified-asphalt mixtures． The test results show that the pavement performance of Evotherm warm-mix modified-as-phalt mixtures are superior to that of hot-mix mixtures，and the two-stage design method can make the materials design for Evotherm warm-mix asphalt mixtures combine with corresponding hot-mix mixtures，which can effectively avoid the risk of current design method，and provide universal significance for other warm-mix technologies References | Related Articles | Metrics

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Application of Orthotropic Unit to Simulating the Interlayer Contact Situation of Asphalt Pavement Fan Ling，Yuan Meijun 2013, 32(4): 614-617.  DOI: