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Lou N.,Shanghai Construction Group | Liu J.-Y.,University of Jinan | Liu J.-Y.,Center for Monitoring Research | Cao H.-Q.,Shanghai Construction Group | Cui W.-J.,Tongji University
Yantu Gongcheng Xuebao/Chinese Journal of Geotechnical Engineering | Year: 2014

The connecting passage of the foundation pit is constructed under the existing optical fiber cables of Greeland Center. The excessive settlement caused by optical fiber cables should be avoided during the construction, which may lead to unfavorable effects. Through finite element modeling and expert discussion, the pipe roofing method is finally adopted for supporting the surrounding soils, and then the connecting passage under optical fiber cables is constructed. Through the field monitoring, the largest settlement of soil is 12 mm, which conforms to the deformation control standards of the optical fiber cable, and the normal use of the existing optical fiber cables is ensured. The pipe roofing construction technology used in the project may provide a good reference for similar projects.

Zhao H.-Y.,Nanjing University | Zhang Y.,Nanjing University | Zhang Y.,Shandong Electrical Power Engineering Consulting Institute | Chen F.-J.,Shanghai Construction Group | And 4 more authors.
Yantu Gongcheng Xuebao/Chinese Journal of Geotechnical Engineering | Year: 2012

The construction method of a box culvert being pushed to replace two pipe roofs is initiated as a city tunnel excavation method in China. This method is complex, and soil deformation is the key factor to test whether the construction method is successful or not and to guarantee the tunnel safety. The soil deformation sensors are introduced based on the distributed fiber sensing technology, their performances are tested in the laboratory, and a three-dimensional deformation monitoring network is designed according to the model tests. The test results and the monitoring data are analyzed. The soil deformation characteristics during the pipe-roofs pushing and box culvert replacement are summarized. This study will play an important role in perfecting the intelligent monitoring system, improving this construction method and analyzing the deformation of engineering soils.

Wang X.,Tongji University | Gong J.,Tongji University | Gong J.,Shanghai Construction Group | Zhao X.,Tongji University
Yanshilixue Yu Gongcheng Xuebao/Chinese Journal of Rock Mechanics and Engineering | Year: 2013

Based on field measured data, the lateral deformation laws of retaining wall, which belongs to super-large deep foundation pit of Shanghai Tower podium, are analyzed. The analytical results show that, during the period from completion of cushion concrete placement to the completion of beam-slab concrete placement, the increment in lateral deformation of retaining wall is very small, indicating that the constraint effect of cushion on deformation of retaining wall is significant. However, due to the eccentric load effect, the lateral deformation of circle wall, which is the support point of cushion, is relatively large; and it leads to a large increment in lateral deformation of measuring point P04 during this period. Combining with the site construction conditions, the constraint effect of cushion concrete is explained. During the period of structure concrete curing, due to the concrete shrinkage of overlong beam-slab structure or bottom plate, the increment in lateral displacement of retaining wall is large. During the curing period of bottom plate, the increment in lateral deformation of measuring point P23 is larger than that caused by soil excavation for the last time. For the short concrete structure, the effect of concrete shrinkage on the lateral displacement of retaining wall can be neglected. Finally, based on the above laws, some suggestions are proposed to control the deformation of retaining wall effectively.

Jiao C.,Nanjing Southeast University | Jiao C.,China Communications Construction Company Ltd. | Li A.,Nanjing Southeast University | Wu X.,Shanghai Construction Group | Dong X.,Nanjing Southeast University
Journal of the Chinese Institute of Engineers, Transactions of the Chinese Institute of Engineers,Series A/Chung-kuo Kung Ch'eng Hsuch K'an | Year: 2013

In this article, the effect of earthquake ground motions, especially spatially varying motion, on the seismic response of a long-span double-deck cable-stayed bridge is investigated. Static and dynamic response analyses, with the focus on internal forces on web members, are carried out on the Shanghai Minpu Bridge which is the longest long-span double-deck cable-stayed highway bridge. Firstly, a program for the generation of multi-ground motions has been developed, based on the multivariate stochastic processes of the weighted amplitude wave superposition method in FORTRAN. Secondly, a refined finite element model composed of beam and shell elements and a simplified model using equivalent beam elements to model girders of the bridge are established in ABAQUS. Geometrical nonlinear static analysis is performed to get initial equilibrium configuration of the bridge for both the above models. Modal analysis is carried out on the initial equilibrium configuration and the natures of mode shapes for the refined model are discussed in detail. The dynamic response analyses under two groups of uniform seismic excitation indicate that the two models result in approximately identical results. Thirdly, the effect of nonlinear viscous dampers, located between the tower and the girder, on movement due to seismic excitation is investigated on the simplified model under uniform excitation. Results show that the dampers magnify the shear force and moment on lower tower columns in the longitudinal direction, but have relatively small effect on the upper tower columns. The shear force and moment of the tower base increase with the damping coefficient in a certain range. Finally, the characteristics of internal force for towers, subsidiary piers, and web members (vertical and oblique web members and side oblique chords) under multipoint excitation are examined. It is concluded that the abrupt changes on the shear envelope curves at the intersection of the tower column and the lower transverse beam are aroused due to the eight nonlinear fluid viscous dampers. The lateral moment of the subsidiary piers increases with the distance from the tower to subsidiary piers. The maximum axial forces of web members of side-span vary acutely, especially those of the vertical and oblique members close to the piers. For side oblique chords, the maximum axial force is uniformly distributed with the exception of members at the piers and the mid-span sections. Therefore, attention should be paid to the fluctuation forces of cables in seismic analysis of long-span cable-stayed bridges, since the uplift of girder ends may cause severe damage to bridges. © 2013 The Chinese Institute of Engineers.

Liu J.,Tongji University | Wu J.,Tongji University | Luo X.,Tongji University | Cui X.,Shanghai Construction Group | Zhang Q.,Tongji University
Tumu Jianzhu yu Huanjing Gongcheng/Journal of Civil, Architectural and Environmental Engineering | Year: 2012

The time-changing analysis model for concrete filled steel tubes was established based on the time-changing concrete model of CEB-FIP MC90, in which the interaction between steel tube and concrete core was considered by the restraint conditions of master and slave nodes. The numerical simulation method was developed for analyzing the whole construction process of high-rise CFST structures. A real structure was taken as numerical example, in which the influence of concrete creep and shrinkage as well as construction process was considered. The results of numerical simulation are compared with those obtained from on-site monitoring. It is shown that the concrete creep and shrinkage as well as construction process have big influence on high-rise CFST structures, which should be taken into account in designs and constructions.

Jiao C.,Nanjing Southeast University | Li A.,Nanjing Southeast University | Wu X.,Shanghai Construction Group
Yingyong Jichu yu Gongcheng Kexue Xuebao/Journal of Basic Science and Engineering | Year: 2012

The influence of nonlinear viscous fluid damper, elastic connection and inelastic connection between tower and gird or between piers and gird were investigated in this study. Shang hai Minpu Bridge was taken as an example and its finite element model was established based on Abaqus. Several groups of nonlinear time-history analysis were carried out and the results showed that nonlinear viscous fluid dampers caused the increase of moment and shear of lower tower column in longitudinal direction and had little influence on upper tower column. Moment and shear in longitudinal direction at the bottom of tower increase with the damping coefficient when the damping exponent was set to constant. Long-span cable-stayed bridges generally have dense and low-period modes, therefore the seismic response of long-span cable-stayed bridges are sensitive to the excitation motions. Elastic or inelastic connections between gird and tower alter the longitudinal drift mode of gird and influence the seismic response of the bridge. The effect of elastic or inelastic connections on the seismic mitigation depends on the earthquake motion inputted and the dynamic characteristics of bridge after above connections are installed. Joint distributions of inelastic connection parameters were presented to discuss their influence on the seismic response of key components. The effects of initial stiffness and yield displacement of inelastic connection are complicated. In contrast, the influence of the yield displacement on the seismic response is relatively more obvious than the initial stiffness.

Jiao C.,Nanjing Southeast University | Li A.,Nanjing Southeast University | Wu X.,Shanghai Construction Group
Zhendong Ceshi Yu Zhenduan/Journal of Vibration, Measurement and Diagnosis | Year: 2012

The influence of traveling wave on the seismic response of long-span double-deck cable-stayed bridge, especially taking into account the web members between decks, has not been studied thoroughly. Shanghai Minpu Bridge, which is the longest double-deck long-span cable-stayed highway bridge, is taken as an example to study the traveling wave on the seismic response in this paper. Finite element model with beam and shell element is established, in which the web members between decks are also modeled. Initial equilibrium configuration for the bridge is acquired through nonlinear static analysis. The modal analysis and geometric nonlinear dynamic analysis are carried out based on the initial equilibrium configuration to get the dynamic characters and seismic responses respectively. The influence of traveling wave on the seismic response is demonstrated by three groups of earthquake motions with different apparent wave velocities. The effect of apparent wave velocities on the seismic response of tower, subsidiary piers and the relative displacement between tower and girder and between subsidiary piers and girder are discussed in detail. It is concluded that the seismic responses of double-deck long-span cable-stayed bridges depend heavily on the apparent wave velocities and the earthquake motions inputted. Therefore the selection of appropriate earthquake motions and the determination of reasonable apparent wave velocities are of much importance to seismic response of bridges.

Wang X.,Tongji University | Gao Z.,Shanghai Construction Group | Wu X.,Shanghai Construction Group | Lv J.,East China Architectural Design and Research Institute | Xia F.,Shanghai Construction Group
Jianzhu Jiegou Xuebao/Journal of Building Structures | Year: 2015

The construction cycle of super high-rise building is long, and the effect of vertical cumulative deformation is a major consideration in the design and construction of the structure. The deformation of vertical members usually occurs due to elastic, shrinkage and creep deformations. The super high-rise building the Shanghai Tower was selected to investigate the vertical deformation. The time-dependent property prediction model of concrete material suggested by CEB-FIP, ACI and PCA and its feasibility were analyzed. The FEA model of the Shanghai Tower was established according to the actual construction progress. The long-term vertical deformations during the construction and after the completion of structure calculated by three prediction models were acquired and the features and difference of long-term deformations calculated by various models were analyzed. Calculating the temperature deformations according to the measured temperature, and comparing the calculated results of vertical deformations with the long-term monitored values, it shows that, using the predicting model suggested by CEB and considering the temperature effect, the calculated values of vertical deformations are in good agreement with the monitored values and temperature fluctuation trends, which indicates that the vertical deformations are significantly affected by seasonal temperature difference. ©, 2015, Science Press. All right reserved.

Jiao C.,Nanjing Southeast University | Li A.,Nanjing Southeast University | Wu X.,Shanghai Construction Group | Gao J.,Shanghai Construction Group
2011 International Conference on Electric Technology and Civil Engineering, ICETCE 2011 - Proceedings | Year: 2011

Steel truss girder is usually used for long span bridges which require much rigid stiffness for heavy loads, such as railway or high way with double decks. Since the fine finite element models for some special analysis are not convenient, researches on the simplification of stiffen girders for finite element models are presented in this paper. Focusing on the characteristic of construction control analysis, equivalent main frame for steel truss girders with double decks is proposed, in which the vertical stiffness of girder is relatively accurate. Finite element model for the construction control analysis is established. Minpu Bridge is taken as an example, three different finite element models are established, modeled with beams and shells (Model 1), modeled with single beam for main girder (Model 2) and modeled with equivalent stuffiness for girders (Model 3). Model 1 can be used for static and dynamic analysis with web members between decks considered. Model 2 is mainly used for earthquake and wind resistant analysis and Model 3 can be employed for construction control analysis. The simplification of steel truss girder provides some references for the simplified analysis of bridges of the same kinds. © 2011 IEEE.

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