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15 February 2015, Volume 34 Issue 1 Previous Issue    Next Issue

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Static, Dynamic and Fatigue Life Analysis of Straddle Type Joint Turnouts Beam Wang Zhixiang, Zhu Ming, Zhang Jixiang 2015, 34(1): 1-5.  DOI: 10.3969/j.issn.1674-0696.2015.01.01 Abstract ( )   PDF (1389KB) ( )   The static, modal and fatigue life analysis of the third segment of joint five-switch beam has been studied by the ANSYS Workbench. The analysis displayed that the maximum equivalent stress under static loads is 52.44MPa, less than the yield limit strength of the material. Maximum deformation is about 0.29mm in the upper beam. There is obvious stress concentration point occurred in the welding position. Frequency of the first modal is about 51Hz. The simulation result of switch beam’s fatigue life is 49.6 years. The results of analysis show that the static strength of the switch beam meets requirements. The deformation position of the first three modes in modal analysis coincides with the static strength deformation. The rigidity of this position needs to be strengthened. The fatigue life of switch beam satisfies the requirement of 25 years life of steel structure. References | Related Articles | Metrics

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Deflection Characteristics of Three-Pylon Suspension Bridge Based on Gravity Stiffness Method Wang Libin, Wu Yong, Jin Bohan 2015, 34(1): 6-11.  DOI: 10.3969/j.issn.1674-0696.2015.01.02 Abstract ( )   PDF (946KB) ( )   The dimensionless deflection expressions of main cable for three-pylon-four-span suspension bridges under concentrated load and distributed load were derived by gravity stiffness method. Then the influence rule of the number of spans, the ratio of side span to main span, dead load and live load intensity on the gravity stiffness deflection of three-pylon-four-span suspension bridge was analyzed respectively. And the new characteristics of three-pylon-four-span suspension bridge which were distinguished from the conventional three-pylon-four-span suspension bridge were also analyzed. These conclusion indicates that the mechanical characteristics of the multi-span main cable under dead and live load determine the basic characteristics of structure stiffness of three-pylon-four-span suspension bridges; the different behavior between one-span cable and multi-span cable causes the difference of mechanical characteristics between two-pylon suspension bridges and three-pylon suspension bridges; and the behavior characteristics of three-pylon suspension bridges based on the gravity stiffness deflection method keeps well consistent with the behavior characteristics based on finite elements method on overall structure. References | Related Articles | Metrics

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Analysis on Vessel Collision with Bridges Based on Nonlinear Finite Element and Study on Impact Force Gao Rongxiong 2015, 34(1): 12-15.  DOI: 10.3969/j.issn.1674-0696.2015.01.03 Abstract ( )   PDF (1724KB) ( )   Vessel collision with bridges, which is a complicated transient dynamic process, usually causes a great risk. The crashing action was applied on bridge structures in the form of equivalent static force in current specifications to calculate the impacting force. The impacting force and damage effect of collision was analyzed on the basis that an inland river bridge in construction was subjected to vessel collision, including geometric and material nonlinearity. The numerical analytical results at different initial velocity and the relation between equivalent static force and crashing velocity with different standards were investigated comparatively, and the impacting force of vessel collision with bridges was discussed. Further, the equivalent impacting force of vessel collision with bridges in inland rivers was also explored. The referential formula of impacting force for bridge design was recommended in the current specifications. References | Related Articles | Metrics

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Fatigue Life Evaluation of U-Rib Butt Weld of the Orthotropic Steel Bridge Ji Bohai, Zhu Wei, Fu Zhongqiu, Chen Xiongfei, Xu Hui 2015, 34(1): 16-21.  DOI: 10.3969/j.issn.1674-0696.2015.01.04 Abstract ( )   PDF (967KB) ( )   The fatigue life of U-rib butt weld of orthotropic steel bridge deck of Jiangyin Yangtze River Highway Bridge was researched, which was based on real-time monitoring of dynamic strain of U-rib butt weld on the Jiangyin Yangtze River Highway Bridge, with the consideration of the rain-flow counting method and BS5400 specification. The stress variation of U-rib butt weld with the load of moving vehicle was obtained by using the fatigue-loaded vehicle model and the traffic flow simulation. The fatigue damage degree was calculated, and the calculation results were compared with the measured ones in detail. The measured results show that the maximum stress amplitude of the slow traffic lane and the fast traffic lane both exceed the fatigue limit of U-rib, which is 70 and 110 MPa respectively, which may cause failure with the accumulation of the fatigue damage. The FEM result shows that although large stress amplitude is produced when the vehicle passes through the bridge, the damage accumulation is mainly in low cycle. The fatigue life of the U-rib which locates on the slow lane is lower than that of the designed bridge life. So it is important to pay attention to the U-ribs of the slow lane. References | Related Articles | Metrics

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Effects of Angular Displacement of Skewback on Stability Performance of Circular Arch Deng Yisan, Xu Bin, Wang Yannan 2015, 34(1): 22-24.  DOI: 10.3969/j.issn.1674-0696.2015.01.05 Abstract ( )   PDF (505KB) ( )   According to the energy criterion of structure stability, the balance equation and the equilibrium stability equation were obtained. Next, the effects of angular displacement of skewback on buckling performance of circular arch were worked out by means of the simultaneous solution of balance equation and equilibrium stability equation. The following conclusions can be drawn from the above research: the angular displacement of skewback will lead to the decrease of buckling load of deep arch; the effects of angular displacement of skewback on buckling load are changed by opening angle of arch; the effects of angular displacement of skewback on buckling load are more evident with the decrease of slenderness ratio of arch; the dividing values of geometric parameter of arch are enlarged with the increase of angular displacement of skewback. References | Related Articles | Metrics

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Influencing Factors of Main Cable Wires Corrosion Rate of Suspension Bridge Chen Xiaoyu, Tang Maolin, Shen Ruili 2015, 34(1): 25-29.  DOI: 10.3969/j.issn.1674-0696.2015.01.06 Abstract ( )   PDF (1126KB) ( )   The factors which influenced the cable steel wires corrosion was classified into two main kinds,that is,external enviroment factors and the own state of steel wires.And other influence factors,such as humidity,temperature,atmospheric pollutants,wire tension,initial loss and the main cable bendine were elaborated in detail.Based on the obtained research results,the influence mechanism of above factors on the cable steel wires corrosion and the corrosion rate was analyzed in detail.And then the main factors influencing the cable steel wires corrosion were obtained.Therefore,the multi-wrre-group corrosion test corrosion test considering the interaction between various factors was proposed,which was more appropriate to simulate the actual main cable corrosion process. References | Related Articles | Metrics

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Reinforcement Boundary of Steel in the Reinforcing Layer of RC Beam under the Secondary Load Zhou Jianting, Li Zhigang, Liu Simeng 2015, 34(1): 30-33.  DOI: 10.3969/j.issn.1674-0696.2015.01.07 Abstract ( )   PDF (667KB) ( )   The ultimate failure of RC beams was analyzed with increasing section method at different initial load to study the effects of secondary load on the relatively height of ultimate compressive region and the maximum strengthening quantity, the calculation formulas of RC strengthened beam’s relatively height of ultimate compressive region and maximum strengthening quantity of steel in the reinforcing layer at different initial load were obtained when the beams strength occurred plastic failure. The Finite Element Analysis (FEA) software ABAQUS was used to do the calculation verification, and the calculation results agreed well with analysis ones. References | Related Articles | Metrics

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Deformation Law Analysis and Safety State Evaluation of Embankment on Broken Line Subgrade Wang Teng, Chen Liang, Zhu Hongzhou, Miao Cunque 2015, 34(1): 34-39.  DOI: 10.3969/j.issn.1674-0696.2015.01.08 Abstract ( )   PDF (1307KB) ( )   In order to study the deformation law of embankment on the broken line subgrade and find the monitoring sensitive point, and then evaluate its safety state based on deformation law, PLAXIS was used to simulate the deformation law of embankment on the broken line subgrade in the filling period, the normal operation period, and the case of rainfall infiltration. Results showed that the monitoring sensitive points of the filling period were mainly distributed in slope crest of each filling layer. In the operation period they were located in the tension fracture area of top and shear outlet of landslide of toe, which was likely due to an arc sliding result from the soil mechanics parameters attenuation. However, monitoring sensitive points would be distributed in the upper part of embankment in rainwater infiltration region when raining. That was because embankment slides locally would be occurred with the increase of rainfall depth. Finally, this paper identified the risk level of the embankment based on the size of the displacement in the process of deformation development of the embankment. References | Related Articles | Metrics

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Experimental Study on the Influence of the Admixture for the Double Grout Guo Qiwu,Yin Xiaobo,Chen Yuanjiang,Wan Xiufeng 2015, 34(1): 40-43.  DOI: 10.3969/j.issn.1674-0696.2015.01.09 Abstract ( )   PDF (644KB) ( )   Contrast tests were carried out on the base of chemical reaction mechanism analysis on the cement-sodium silicate slurry, to research the influence of two different kinds of admixtures including Aluminum chloride solution and Disodium hydrogen phosphate on the solidification characteristics of slurry. The gelation time test, stone rate test, compressive strength test and durability test were included. Therefore, the influence law of the two admixtures on the solidification characteristics of cement-sodium silicate slurry was obtained preliminarily. References | Related Articles | Metrics

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Comparison for Two Methods of Measurement of Foamed Asphalt Viscosity Xu Dawei, Zhang Shuai 2015, 34(1): 44-47.  DOI: 10.3969/j.issn.1674-0696.2015.01.10 Abstract ( )   PDF (648KB) ( )   Brookfield viscometer and improvement of Brookfield viscometer were used to measure foamed asphalt, and 70# conventional asphalt and SBS modified asphalt were selected to produce foamed asphalt. Compared with two kinds of foamed asphalt viscosity measurement method, the results are as follows: asphalt bubbles influencing shear stress should be taken into consideration. Bubbles of 70# conventional asphalt influences viscosity a lot, and improvement of rotation viscosity is less than 70# conventional asphalt, but rotation viscosity is larger than 70# conventional asphalt. Because of larger viscosity of SBS modified asphalt, inerratic bubbles of asphalt have little effect on measurement of viscosity. Improvement of rotation viscosity and rotation viscosity are less than that of SBS modified asphalt. In order to measure the viscosity of foamed asphalt more accurately, it is suggested that the caliber of sample tube should be increased to avoid the influence of asphalt bulbbles on the shear stress. References | Related Articles | Metrics

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Influence of Processing and Storage Temperature on SBS Modified Asphalt Performance Han Sen , Niu Dongyu, Chen Kai, Gao Jingwei, Li Jun 2015, 34(1): 48-53.  DOI: 10.3969/j.issn.1674-0696.2015.01.11 Abstract ( )   PDF (788KB) ( )   Four kinds of the processing temperatures (160,170,180,190 ℃) and three kinds of the storage temperatures（90, 120,150 ℃）, which were in different range, were selected to process and store the different SBS modified asphalt (E+S-YS, E+S-YY, S+S-YY). The temperature sensitivity, high temperature performance and low temperature performance were analyzed by asphalt experimentation and repeat creep test. The results show that the different processing and storage temperatures affect the performances of three kinds of SBS modified asphalt differently. When the processing temperature is 180 ℃ and the storage temperature is 150 ℃, the various performances of S-YY modified asphalt achieve the optimal effect; while the processing temperature is 170 ℃ and the storage temperature is 120 ℃, the various performances of S-YS modified asphalt achieve the optimal effect. The recommended value of the processing and storage temperature for enhancing the performance of different SBS modified asphalt was proposed. References | Related Articles | Metrics

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Water Damage Mechanism of Epoxy-Asphalt Concrete Zhou Wei , Zhao Hui, Wen Jun , Cai Fangchang , Jiang Tao 2015, 34(1): 54-59.  DOI: 10.3969/j.issn.1674-0696.2015.01.12 Abstract ( )   PDF (1276KB) ( )   Combining with the photomicrographs of epoxy-asphalt concrete and fluorescence photomicrographs of the section of epoxy-asphalt concrete, the mechanical strength, water absorption, pH value and DMA analysis of epoxy-asphalt was used before and after freeze-thaw cycles, to investigate the damage mechanism of mechanical properties of epoxy asphalt under freeze-thaw cycles. The results show that: the causes of the damage of epoxy-asphalt concrete under freeze-thaw cycles were that the dispersion of epoxy-asphalt-aggregates was destroyed in the physical aspects and the curing structural of epoxy were bracken in the chemistry aspects. At the initial stage of freeze-thaw cycles, the water molecules into the epoxy asphalt system cause epoxy hydrolyzed, which destroys the molecular structure of the cross-linked epoxy resin curing; at the late stage of freeze-thaw cycles, asphalt gradually separates out of the curing system, which causes the curing system structure damaged, the tensile strength of the system reduced by about 32.42 % from 5.12 MPa to 3.51 MPa, and the adhesive strength reduced by 3.25 % from 47.87 MPa to 46.31 MPa.