Survey and Design Institute Co.

Zhengzhou, China

Survey and Design Institute Co.

Zhengzhou, China
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Chen X.J.,Guilin University of Technology | Huang X.,Guilin University of Technology | Xiao G.Y.,Guilin University of Technology | Chen H.B.,North China University of Technology | Qi Y.L.,Survey and Design Institute Co.
Unsaturated Soil Mechanics from Theory to Practice - Proceedings of the 6th Asia-Pacific Conference on Unsaturated Soils | Year: 2016

To investigate the shear strength characteristics of the remolded laterite soil in Guilin, a series of triaxial tests were conducted to study the influences of the dry density and moisture content of the remolded laterite soil on the shear strength. The experimental results show that the strengths of remolded saturated laterite soil and unsaturated one are quite different under the same optimum moisture content. The relationship of cohesion and internal friction angle with the dry density of the remolded unsaturated laterite soil can be represented by a convex quadratic polynomial function. However, the concave quadratic polynomial curve needs to describe the relation of the cohesion and internal friction angle with the dry density of the remolded saturated laterite soil. © 2016 Taylor & Francis Group, London.

Zhang S.,Hunan University | Zhang S.,Survey and Design Institute Co. | Shao X.,Hunan University | Cao J.,Hunan University | And 2 more authors.
Tumu Gongcheng Xuebao/China Civil Engineering Journal | Year: 2016

In order to decrease the risk of fatigue cracking in orthotropic steel decks, a lightweight composite bridge deck with bulb flat ribs was proposed. As a typical bridge with lightweight composite bridge deck, the Sencond Dongting Lake Bridge is taken as an example, in which the local finite element models of steel truss girder and the sub-models of bulb flat rib-diaphragm connections were established. Then the shape of cutouts and thickness of diaphragms were investigated based on the hot spot stress method. The results show that the fatigue properties of 3 typical details at bulb flat rib-diaphragm connections were affected significantly by the thickness of diaphragms. On the basis of comprehensive comparison, it is concluded that the fatigue properties of apple-shaped cutout are the best. Additionally, fatigue test was performed on a full-scale model to verify the fatigue strength of 3 details at bulb flat rib-diaphragm connections in a lightweight composite bridge deck with 16mm diaphragms and apple-shaped cutouts. In the test, the fatigue stress range for the most unfavorable detail, i.e. the free edge of the cutout, was 90.6MPa and no fatigue cracks developed after 2.5 million loading cycles. The research results show that the key details in the lightweight composite bridge deck with bulb flat ribs have good fatigue performance and can satisfy the design requirements of Sencond Dongting Lake Bridge. © 2016, Editorial Office of China Civil Engineering Journal. All right reserved.

He X.-H.,Central South University | He X.-H.,National Engineering Laboratory for High Speed Railway Construction | Gai Y.-B.,Central South University | Gai Y.-B.,National Engineering Laboratory for High Speed Railway Construction | And 3 more authors.
Bridge Construction | Year: 2017

The main bridge of the Pingtang Bridge is a steel and concrete composite girder cable-stayed bridge with triple pylons, double cable planes and with span arrangement (249.5+550+550+249.5) m. The pylons No.15 (side pylon), No.16 (middle pylon) and No.17 (side pylon) of the bridge are respectively 320, 328 and 298 m high. The bridge is located in the mountainous region and the site of the bridge is in the seismic area. To have an understanding of the influences of the seismic action on the internal forces of the pylons and on the displacement of the pylons and main girder, the software SAP2000 was used to establish the finite element model for the bridge, the seismic responses of the bridge were analyzed, respectively using the response spectrum method and the nonlinear time-history analysis method and the influences of the pylon height differences on the seismic performance of the bridge were analyzed as well. The results of the analysis demonstrate that under the seismic action, the bending moment of the footing and the displacement of the top of the middle pylon are greater than those of the side pylons. For the 2 side pylons, the bending moment of the footing and the displacement of the top of the higher pylon No.15 are even greater. The longitudinal and transverse vibration of the main girder does not couple substantially and relatively to the longitudinal earthquake, the vertical displacement of the main girder is influenced by the transverse earthquake more greatly. The calculation results of the mentioned 2 methods are close, but in the nonlinear time-history analysis method, the nonlinearity of the bearing is considered and it is hence proposed that the results of the nonlinear time-history analysis should be taken as the basis of the seismic design. © 2017, Journal Press, China Railway Bridge Science. All right reserved.

Zhang J.,Chang'an University | Liu H.,Chang'an University | Wang P.,Chang'an University | Pei J.,Chang'an University | And 2 more authors.
Road Materials and Pavement Design | Year: 2017

In order to quantitatively evaluate aggregate gradation and distributing homogeneity in asphalt mixture, digital image processing techniques were used to obtain the two-dimensional gradation characteristics in several cross-sections of the coring specimen, and the stereoscopy theory was applied to reconstruct the three-dimensional gradation characteristics, which was compared with the actual gradation, and a correction factor was deduced. It is found that the relative error between corrected and actual aggregate gradation is less than 5%. Then, the aggregated distributing information in horizontal and vertical sections were analysed to establish the horizontal and vertical distributing homogeneity indexes, respectively. The horizontal distributing homogeneity can be evaluated by the variation of inertia of the X-axis, Ix, during rotating, and the vertical distributing homogeneity can be evaluated by the statistical index of the aggregate centroids, Sa. The smaller the Ix variation, the better the horizontal distributing homogeneity. The larger the Sa, the better the vertical distributing homogeneity. © 2017 Informa UK Limited, trading as Taylor & Francis Group.

Ge Z.,South China University of Technology | Wang H.,Rutgers University | Yao H.,South China University of Technology | Zhang Q.,South China University of Technology | Zhang L.,Survey and Design Institute Co.
Journal of Testing and Evaluation | Year: 2016

Moisture transport in asphalt mixtures is influenced by the distribution and connectivity of air voids in the mixture. Therefore, characterization of air void structure is important for predicting moisture damage potential. The purpose of this paper was to detect the air void content of asphalt pavement using ground penetration radar (GPR) and then evaluate the moisture damage potential of asphalt mixtures with different air void contents. In particular, an innovative device, a dynamic water pressure tester (DWPT), was used to evaluate the resistance of asphalt mixture to moisture damage. A rotary loaded wheel tester (RLWT) was used to measure rutting resistance of asphalt mixture before and after being tested by DWPT. A linear relationship between air voids and the amplitudes of wave valley in the GPR signal was found. It suggested that the GPR waveform could be used to detect the air void content of asphalt pavement layers consistent with laboratory measurements. The relationship between air voids and rut depths measured with RLWT showed that an increase in air void content led to an increase in rut depth. Test results in the laboratory indicated that dynamic water pressure resulted in the greater reduction of strength and increase of rut depth if the asphalt mixture has higher air void contents. © 2016 ASTM Int'l all rights reserved.

Zhang S.,Survey and Design Institute Co. | Zhang S.,Hunan University | Shao X.,Hunan University | Cao J.,Hunan University | And 3 more authors.
Journal of Bridge Engineering | Year: 2016

An innovative lightweight composite deck (LWCD) is proposed for steel bridges to avoid premature fatigue cracking. The composite deck is composed of an open-ribbed orthotropic steel deck (OSD) and a thin ultrahigh-performance concrete (UHPC) layer. This study is based on a suspension steel bridge in China, namely, the Second Dongting Lake Bridge. The following investigations were performed: (1) preliminary finite-element analysis (FEA) was carried out to evaluate the vehicle-induced stress ranges (i.e., σ = σmax - σmin) of six typical fatigue-prone details; (2) parameter analyses were performed to investigate the effects of the shape of cutouts and the thickness of the floor beams; and (3) two fatigue tests, one that used a full-scale LWCD panel and another that used a LWCD beam specimen, were conducted to reveal fatigue performance of the OSD and the stud shear connectors, respectively. Results of the preliminary FEA show that, with the contribution of the UHPC layer, the vehicle-induced stress ranges at some fatigue details of the LWCD, such as the rib-deck plate welded joints and the splice welds of the longitudinal ribs, were reduced to be less than their constant-amplitude fatigue limits, which indicates theoretically infinite fatigue lives of these details. The parameter analyses reveal that the apple-shaped cutout had relative good fatigue properties among the four cutout schemes and that the thickness of the floor beams is recommended to be 14-18 mm. According to the fatigue tests on the composite panel specimen and on the composite beam specimen, both the open-ribbed OSD and the stud shear connectors exhibited satisfactory fatigue endurances, which were much greater than 2 million cycles. The current theoretical and experimental investigations reveal that the proposed open-ribbed LWCD has favorable fatigue performances. © 2016 American Society of Civil Engineers.

Wang X.-F.,Chang'an University | Wang X.-F.,Survey and Design Institute Co Ltd | Cao R.-J.,Jiangsu Transportation Research Institute
Chang'an Daxue Xuebao (Ziran Kexue Ban)/Journal of Chang'an University (Natural Science Edition) | Year: 2011

In light of the complexity of rubber asphalt modification mechanism, such means as scanning electron microscopy, infrared spectroscopy, differential thermal analysis, microscopic structure analysis, component analysis were adopted to study the components of the asphalt before and after modifying, and chemical analysis of rubber powder are adopted to study the modification mechanism of asphalt rubber blending system. The results indicate that the swollen rubber powder is mutually-adhered to form a network structure, and the matrix asphalt changes from homogeneous body into a two-phase continuous blending structure system constituted by rubber powder and asphalt; physical swelling dominates the system, accompanied by a little chemical reaction and with the prolongation of time, the chemical reaction becomes more obvious; the swollen rubber powder forms damping effects to improve the viscosity of rubber asphalt. The modification of asphalt comes from two aspects: firstly, the network structure formed by swollen rubber powder; secondly, the modification of the asphalt composition resulting from rubber powder desulphurization degradation. The natural rubber has better performance in modifying asphalt than synthetic rubber.

Cheng G.,Survey and Design Institute | Chen G.,Survey and Design Institute Co.
Modern Tunnelling Technology | Year: 2013

Based on the actual construction of the Shizishi tunnel on the Lijiang to Panzhihua highway, which crosses over the Xinzhuang railway tunnel, the cracking and spalling of the lining in the railway tunnel was comprehensively analyzed through numerical simulation and observed phenomena. It was determined that the main factor of the newly-built highway tunnel's effects on the existing railway tunnel was blasting vibration, especially within the section with poorer quality. The reinforcement measures taken regarding the existing railway tunnel and treatment measures used for the newly-built highway tunnel are presented in this paper as a preliminary reference for similar projects.

Wang X.-F.,Chang'an University | Wang X.-F.,Survey and Design Institute Co.
Chang'an Daxue Xuebao (Ziran Kexue Ban)/Journal of Chang'an University (Natural Science Edition) | Year: 2011

In order to decide the optimal timing of the aspalt pavement preventive maintenance, a decision model was developed. Through analyzing the change of pavement performance after the maintenance treatment application, the model defined the pavement composite benefit, decided the analysis period and set up the four decision making indexes. An application example shows that the model can reflect the roles of various pavement performance indexes, objectively describe the characteristics of maintenance object; based on the four decision indexes (the composite benefit value, the equal annual cost, the benefit index, and the expected extension of life), the five decision principles can be formed, they are the minimum cost principle, the maximum composite benefit principle, the maximum unit cost benefit principle, the longest service term principle and the comprehensive balance principle; these principles may meet the needs of different decision makers, and the decision precision lies on the data of pavement performance.

Li Q.,Survey and Design Institute Co. | Wan J.,Survey and Design Institute Co. | Cao G.,Survey and Design Institute Co.
Lecture Notes in Electrical Engineering | Year: 2016

Urban traffic information construction still exists some systemic problems, such as insufficient coordination, scattered resources, unbalanced development level, etc. The article presents the urban traffic monitoring, and the service system framework. The system is composed of decision support, information services, coordinated and integrated monitoring, analysis, and resource management. The system is used to promote urban transport information resources’ exploitation and utilization, and promote transportation system network linkage and collaborative applications. © Springer-Verlag Berlin Heidelberg 2016.

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