Survey and Design Institute
Survey and Design Institute
Song X.,Central South University |
Melhem H.,Kansas State University |
Cheng L.,Survey and Design Institute |
Xu Q.,Central South University
Journal of Bridge Engineering | Year: 2017
Creep, shrinkage, and temperature drops will shorten the main girder and create additional internal forces in the piers of continuous rigid-frame bridges. Horizontal jacking forces can be applied at the ends of a closure segment before casting to improve the stress state in the piers. Multispan continuous rigid-frame bridges have several closure segments and usually have different jacking forces. In general, the determination of the optimal jacking forces is relatively difficult because of their compound effects on the bridge piers. In this study, multiobjective linear programming was used to calculate the jacking forces by selecting the stress in the piers as the objective function in the service stage and the stresses at the various construction stages as constraints. The minimum tensile stress in the piers was obtained by an iterative process that allowed for the creep effect of the jacking forces to be included in the calculations. The results obtained show that the proposed method is convenient for design, and the appropriate jacking forces can be determined to minimize detrimental long-term effects. Creep caused by jacking forces was found to affect pier stress significantly. In comparison, jacking forces were found to have a smaller effect on the internal stresses of the main girder. Calculation results show that if jacking force is not applied, the long-term effect of creep will generate large stress variations between the top and bottom of the piers and may cause cracking. However, when jacking force is applied, stresses in the piers in the service stage are relatively uniform. © 2016 American Society of Civil Engineers.
Liu T.,Survey and Design Institute |
Huang H.,State Key Laboratory for Disaster Reduction in Civil Engineering |
Sun L.,State Key Laboratory for Disaster Reduction in Civil Engineering
IABSE Congress Stockholm, 2016: Challenges in Design and Construction of an Innovative and Sustainable Built Environment | Year: 2016
In recent years, magnetorheological damper (MR damper) has been proposed for controlling vibrations of long stay cables because of its semi-active features, where active control strategy can be adapted without inquiring large power resources. However, the highly nonlinear feature of the MR material leads to a relatively complex representation of its mathematical model, resulting in difficulties of carrying out effective control strategies on cable vibration. In this paper, a simple optimal control strategy is proposed for suppressing multi-mode cable vibrations using MR damper based on nonlinear modeling. Firstly, the nonlinear Bouc-Wen model is employed to accurately portray the salient characteristics of the MR damper. Then, the desired optimal damper force is determined from the universal design curve of nonlinear damper. Finally, the input voltage (current) of MR damper corresponding to the desired optimal damper force is calculated using a piecewise linear interpolation scheme. Simulation study has been carried out to validate the effectiveness of the proposed semi-active control scheme for multi-mode cable vibration control under white noise excitations.
Wang X.,Tongji University |
Luo F.,Tongji University |
Su Z.,Survey and Design Institute |
Ye A.,Tongji University
International Journal of Geomechanics | Year: 2017
A key challenge for estimating seismic response of piles and soils in liquefied and laterally spreading ground is the efficient prediction of local loosening phenomenon (shear localization) at the interlayer between the liquefied loose sand and the overburden crust. To this end, a simplified finite-element (FE) model was developed. In the soil model, a soft interlayer element with a thickness and corresponding low reference shear modulus was developed to represent the shear localization phenomenon. The proposed FE models were then used to simulate centrifuge tests of a single pile, a two-pile group, and a six-pile group in sloping liquefiable profiles that lead to lateral spreading. Predicted results of the shear-localization-induced soil lateral spreading displacement, as well as the structural response, agree reasonably well with the test records, indicating that the proposed FE model is capable of approximating the seismic responses of soil and piles in liquefied and laterally spreading ground. In addition, a parametric analysis was performed to build a relationship between the thickness and the low reference shear modulus of the soft interlayer element. © 2016 American Society of Civil Engineers.
Wu W.-Q.,Nanjing Southeast University |
Yu J.-Y.,Nanjing Southeast University |
Yu J.-Y.,Survey and Design Institute
Bridge Construction | Year: 2016
To improve the design safety and service reliability of the hangers of tied arch bridge, the asymmetric parallel double hangers system was proposed for application to the bridge based on the idea of the bridge failure safety design. The Baoguo Jinsha River Bridge (a half-through rigid arch bridge with flexible tie members and with a main span of 160 m) in Panzhihua was cited as an example and the failure safety design method for the hangers of the tied arch bridge was studied. The fatigue life of the hangers of the asymmetric parallel double hangers system were predicted and analyzed, using the Palmgren-Miner linear cumulative damage theory, the finite element models for the whole bridge of the bridge with the single and/or double hanger (s) system were established, using the software ABAQUS and the stress changing laws of the remaining hangers of the bridge at the time of sudden break of the end hanger (s) were analyzed as well. The results of the analysis indicate that the sectional area differences of the double hangers will significantly influence the fatigue life differences of the hangers and will cause the two hangers to have the significantly different fatigue life. The safety of the tied arch bridge with the asymmetric parallel double hangers system is significantly higher than that of the tied arch bridge with the single hanger system and the application of the structural failure safety design theory to the design of the hangers of the bridge is feasible. © 2016, Wuhan Bridge Research Institute. All right reserved.
Zhang P.,Jilin University |
Zhang P.,Survey and Design Institute |
Chen J.,Jilin University |
Zhang L.,Jilin Institute of Architecture and Civil Engineering |
Xiao Y.,Chongqing Three Gorges University
Yanshilixue Yu Gongcheng Xuebao/Chinese Journal of Rock Mechanics and Engineering | Year: 2012
The stability of lining structure is influenced by under-excavation and over-excavation of tunnels. It is of great significance to understand the surrounding rock stress and ensure construction safety by studying the over-excavation and under-excavation rules of tunnels. Based on the multi-scale function of wavelet analysis and the statistical self-similarity between the over-excavation and under-excavation of tunnel section profile, the fractal dimensions of 47 tunnel section profiles were calculated by the wavelet analysis. According to the statistical data of joint parameters obtained by field investigation, relationship between the fractal dimension of section profile and joint parameters of tunnel surrounding rocks was analyzed. A function for evaluating the stability of tunnel surrounding rocks was established. With the increase of the fractal dimension, the stability of surrounding rocks gets worse. As the angle between the tunnel axis and joint strike and the over-excavation percentage increase, the fractal dimension of section profiles decreases. When the joint space increases from 0.25 to 0.40 m, the fractal dimension of section profile also decreases.
Jianhua H.,Survey and Design Institute |
Ruili S.,Southwest Jiaotong University
Journal of Bridge Engineering | Year: 2014
The recently completed Aizhai Bridge in the west of Hunan Province in China is a long-span suspension bridge across a deep canyon. In view of the particular problems posed by the surrounding landscape and geologic conditions, and to minimize the impact of the bridge on the natural environment, a novel pylon-girder detached suspension structure was adopted, in which there is a large difference in the span between the main cable and the stiffening girder. As part of the design process, a method for stability analysis of the combined system of pylon, anchorage, tunnel, and rock cliff was developed. In addition, to solve the problems involved in the transportation and erection of the stiffening girder of such a long-span suspension bridge in a mountainous area, a novel girder-conveying track cable method was developed. © 2014 American Society of Civil Engineers.
Chen B.,Fuzhou University |
Mu T.,Survey and Design Institute |
Chen Y.,Shenzhen Municipal Design and Research Institute Co. |
Huang J.,Fuzhou University
Jianzhu Jiegou Xuebao/Journal of Building Structures | Year: 2013
Steel-concrete composite structure is one of the main structures in civil engineering construction. In bridge engineering, composite members can be classified into three types according to the basic bearing behavior, i. e., composite beam, composite column and composite arch. In this paper, the main structure forms and general application of steel-concrete composite bridges in China are described; the research development and engineering application of the new composite structure types presented in recent years are focused on. The traditional steel-concrete composite bridges, such as the shaped steel-concrete slab composite girder, the PC box girder with corrugated steel webs and concrete filled steel tube arch, have been widely used and their specification system has been established by far. In the future, the application experience should be constantly summed up so as to further improve the specifications. At the same time, it is necessary to track closely the latest international trends and carry out innovative research. The research and development of new composite bridge have become very active in our country in recent years. Many new types of steel-concrete composite bridge structures were developed, such as the deck slab with stiffened scaffolding and CFST composite truss, corrugated steel web-CFST composite beam, CFST stiffened scaffolding composite columns, CFST main members with reinforced connection members composite columns and hybrid columns and steel webs (bars)-concrete arch bridge. Some of them have been used in few engineering projects, while others have not been used. In the future, it is important to strengthen their application and popularization, conduct application technology research on the engineering practice requirement, form application guide or technical standards, and make contribution to the development of the composite structures and technical progress of bridge engineering.
Zhou X.,Central South University of forestry and Technology |
Luan J.,Survey and Design Institute |
Zhang D.,Central South University of forestry and Technology
Advanced Materials Research | Year: 2013
With the wide applications of post-tensioned concrete structures, the grouting conditions of tendon ducts are paid more attentions. In order to accurately assess the internal grouting quality of the grouted tendon ducts and certainly guarantee the lifetime of prestressed concrete structures Ground Penetrating Radar (GPR), which is a kind of nondestructive testing (NDT) method, has been applied to inspect and evaluate qualitatively and quantitatively on the grouting defects, respectively. A series of in-house tests were carried out for simulating the defects of tendon ducts by foams with different sizes. The results show that the GPR technic was one of the optimal methods for inspecting the internal grouting quality of grouted tendon ducts for post-tensioned concrete structures. © (2013) Trans Tech Publications, Switzerland.
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 Y.,China Railway Major Bridge Reconnaissance and Design Institute Co. |
Zhong N.,Chongqing Expressway Group Co. |
Zhuang W.,Survey and Design Institute |
Zheng X.,Survey and Design Institute
Proceedings of the Institution of Civil Engineers: Bridge Engineering | Year: 2014
The Guanyinyan Yangtze River Bridge is the key structure on the second ring highway of Chongqing City, southwest of China. The bridge is a cable-stayed bridge with a main span of 436 m. The main girder is a steel-concrete composite girder with a total width of 36?2 m. The final design solutionwas based on an extensive comparison of proposals. Themain bridge was constructed using the balanced cantilever method. This paper presents the challenges in design and static analysis of the bridge, including the detailed design, global static analysis, local finite element model analysis, the determination of the allowable maximum thickness of steel plate against fatigue and brittle fracture induced by low temperature.