Hefei, China

Hefei, China
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Wu W.,Nanjing Southeast University | Shan H.,China Design Group Co. Ltd | Yang S.,Anhui Transport Consulting & Design Institute Co. | Tang Z.,Nanjing Southeast University
KSCE Journal of Civil Engineering | Year: 2017

In concrete bridge widening projects, it is a common practice to provide a monolithic connection between the existing and new decks by casting an in situ concrete stitching slab. As a result, the differential foundation settlement between the two decks has a considerable effect on the concrete stitching slab and the widened bridge. The widened bridge noted as multi-girder bridge is a simple-supported, precast, voided-slab bridge, located on the Beijing–Shanghai Expressway in east of China. When using a grillage Finite Element Model (FEM) to model the mechanical behavior of the multi-girder bridge after it has been widened, the general approach to account for the effect of differential foundation settlement is to load a calculated forced vertical displacement to the bearing of each precast slab of the new bridge. However, there is no suitable mathematical model to be used for calculating the forced displacement for all new slab beams, which requires the ability to describe the transverse distribution mode of these forced displacement under a given differential foundation settlement. Under this background, an experimental study and finite element analysis are conducted to find this suitable mathematical model in this paper. Based on a comprehensive research results, a quadratic curve model was considered to be a suitable mathematical model to meet the design need of such type of widened multi-girder bridge, and its quadratic equation was also derived in the paper. This finding is the key assumption for accurately analyzing the mechanical behavior of a widened multi-girder bridge, with a grillage finite element model. © 2017 Korean Society of Civil Engineers and Springer-Verlag GmbH Germany

Ding N.,Hunan University | Ding N.,Anhui Transport Consulting & Design Institute Co. | Shao X.,Hunan University
Tumu Gongcheng Xuebao/China Civil Engineering Journal | Year: 2015

Fatigue performance is an important issue in the design of steel bridge decks. In order to study the fatigue performance of light-weighted composite bridge deck, local finite element models of Humen Bridge in Guangdong were established. Hot spot stress approach is used to calculate the stress ranges of typical fatigue-cracking details of steel bridge deck with different ultra-high performance concrete (UHPC) layer thickness. The stresses of UHPC layer and the shear forces in light-weighted 45 mm-thick UHPC layer composite bridge deck are analyzed and the flexural fatigue performance of the UHPC layer is assessed basing on the results of two full-scale model fatigue experiments. The results show that the UHPC layer has more influence on the stress ranges of rib-to-deck plate joints than other details. When adopting 45mm thick UHPC layer, stress ranges of rib-to-deck plate joints can be reduced between 51% and 82%, while for other details, the stress ranges ars only reduced about 20%. Consequently, the risk of fatigue cracking in rib-to-deck plate joints, longitudinal rib splice joints and cope holes in the crossbeams can be effectively eliminated. The maximum tensile stress of UHPC layer is 11.91 MPa, and the two fatigue tests show that the flexural fatigue performance of UHPC is far beyond the requirements of Humen Bridge. ©, 2015, Editorial Office of China Civil Engineering Journal. All right reserved.

Chen R.,Hunan University | Chen R.,Zhejiang University | Jiang P.,Anhui Transport Consulting & Design Institute Co. | Duan X.,Zhejiang University | And 2 more authors.
Tiedao Xuebao/Journal of the China Railway Society | Year: 2016

The probability distribution of dynamic stress is the main factor of the limit state design of the subgrade. In this paper, a 3D finite element model for vehicle-slab track-subgrade was built, realizing the probability statistics of dynamic stress of subgrade with high speed trains running under German low interference spectrum with three typical speeds. Based on the probability statistics, the mean values and the distribution of variation coefficients of dynamic stress amplitude along the depth of the subgrade were given. Additionally, the influence of train speed on the mean values and variation coefficients was analyzed. Finally, the normal distribution of dynamic tress amplitude was verified by the Kolmogorov rule. The dynamic stress at each subgrade depth during train operation was found to follow the normal distribution. The probability distribution characteristics of the dynamic stress obtained in this paper can serve as a basis for the reliability analysis of the accumulated settlement of the subgrade. © 2016, Editorial Office of Journal of the China Railway Society. All right reserved.

Modern Tunnelling Technology | Year: 2014

As for the construction of Nanshan tunnel in Anhui province, the ribbed beam structure is adopted to solve the problem of environmental disruption caused by multi-arch tunnelling on valley line. The asymmetric embedded ribbed beam structure used in the tunnel is a new tunnel structure type and construction technology, by which cutting the mountain can be avoided through actively controlling the mountain deformation and mined excavation of the tunnel. Consequently, this design method provides a reference to similar projects. ©, 2015, Editorial Office of "Modern Tunnelling Technology". All right reserved.

Zhou M.-D.,Lanzhou Jiaotong University | Zhou M.-D.,Anhui Transport Consulting & Design Institute Co. | Li L.-Y.,Lanzhou Jiaotong University | Zhang Y.-H.,Lanzhou Jiaotong University
Zhongguo Gonglu Xuebao/China Journal of Highway and Transport | Year: 2015

In order to accurately analyze shear-lag effect of thin-walled box girder, fundamental expression of the shear-lag warping displacement function was derived from the relationship between in-plane shear deformation and longitudinal displacement of flanges. Considering the axial self-equilibrium condition for shear-lag warping stress, the shear-lag warping displacement function was modified to be suitable for box girders with cantilever plates. The deviation between centroidal axis and neutral axis of cross section due to shear-lag effect was demonstrated. The influences of the modified term of shear-lag warping displacement function and the ratios of depth to width, width to span and the cantilever plate width to top plate width on the warping stress were analyzed in detail. The results show that the stresses at the mid-span cross section of simply-supported box girder calculated by shear-lag warping displacement function are in good agreement with test results and those by finite element method. The effect of the depth to width ratio is relatively small while those of the width to span ratio and the cantilever plate width to top plate width ratio are much larger. The effect of the modified term of shear-lag warping displacement function on warping stress reaches 18% when the plate width ratio is 1.5. ©, 2015, Xi'an Highway University. All right reserved.

Zhou M.-D.,Lanzhou Jiaotong University | Zhou M.-D.,Anhui Transport Consulting & Design Institute Co. | Li L.-Y.,Lanzhou Jiaotong University | Zhang Y.-H.,Lanzhou Jiaotong University
Gongcheng Lixue/Engineering Mechanics | Year: 2015

In order to analyze the influence of shear effect on mechanical characteristics of thin-walled box girders, the paper uses the shear equilibrium differential equation of microplate to derive the bending displacement function for thin-walled box girders, which accounts for the in-plane shear effect of girder plates. The additional deflection induced by shear effect is adopted as the generalized displacement of a thin-walled box girder. By defining the generalized moment and warping displacement function, the shear deformation state is separated from the whole flexural deformation state and treated as a fundamental deformation state. Considering the self-equilibrium of shear warping stress, the paper introduces two sectional characteristic parameters in the generalized warping displacement function. The numerical example of a two-span continuous box girder shows that the stresses at the mid-span cross section calculated by applying the shearing and bending displacement function are in a good agreement with test results and those by finite element method. The shear effect increases the mid-span deflection of the box girder under concentrated and uniformly distributed loads by 27% and 24%, respectively. ©, 2015, Tsinghua University. All right reserved.

Peng Y.-H.,Chang'an University | Wang X.-Y.,Chang'an University | Lu J.-N.,Chang'an University | Wang W.,Anhui Transport Consulting & Design Institute Co. | Zhang H.-F.,Chang'an University
Zhongguo Gonglu Xuebao/China Journal of Highway and Transport | Year: 2016

In order to improve the service level of expressway maintenance work zone, based on VISSIM to create and design a traffic simulation model with speed of 120 km·h-1 two-way four-lane expressway maintenance work zone, work saturation, average speed, traffic density and average travel delay of chosen road were contrasted and selected as the service level evaluation indexes of expressway maintenance scheme. The length of the maintenance work zone was analyzed and determined by dynamic comprehensive evaluation method. The results show that under the conditions of the outer lane closure mode and the work zone using the progressively speed limit (60-80 km·h-1), the correspondence relationships of work zone length threshold value and service level under different traffic volumes and carts rates are obtained; under the conditions of the half road closure mode, taking into account the driving characteristics of oversize vehicle and the work zone using the progressively speed limit (40-80 km·h-1) mode, it is found that the service level of corresponding work zone length is lower than that in the outer lane closure mode under the same traffic volume and carts rate and the correspondence relationships of work zone length threshold value and service level under different traffic volumes and carts rates are obtained. The results can provide a reference for work zone length determination of the expressway maintenance for traffic organization scheme. © 2016, Editorial Department of China Journal of Highway and Transport. All right reserved.

Zhang H.,Chang'an University | Zhang H.,Henan University of Technology | Du X.,Anhui Transport Consulting & Design Institute Co. | Wang D.,Chang'an University
Jiangsu Daxue Xuebao (Ziran Kexue Ban)/Journal of Jiangsu University (Natural Science Edition) | Year: 2016

To investigate the comprehensive performance of fiber asphalt mixture, four types of fiber asphalt mixture with polyester, cellulose, basalt and sepiolite fibers were studied by the tests of wheel tracking, low temperature bending, freeze-thaw splitting and fatigue stability. Taking dynamic stability, low temperature bending strain, freeze-thaw splitting strength ratio, fatigue life and cost per square meter as evaluation indexes, the weight coefficient grey target theory was proposed to determine the best scheme based on road performance and cost-effectiveness. The results show that the grey target model can be improved by the introduction of entropy weight method to effectively solve the problems of traditional grey target evaluation model and increase the evaluation accuracy. The basalt fiber asphalt mixture has better road performance and cost-effectiveness than other three fiber asphalt mixtures under the same conditions. © 2016, Editorial Department of Journal of Jiangsu University. All right reserved.