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Cai F.,Nanjing University of Technology | Cai F.,Wenzhou Architectural Design and Research Institute | He L.,Nanchang Hangkong University | Zhou X.,Nanjing University of Technology | And 2 more authors.
Zhongnan Daxue Xuebao (Ziran Kexue Ban)/Journal of Central South University (Science and Technology) | Year: 2013

Based on the finite element analysis of software ABAQUS, the one-dimensional subroutine of continuous drainage boundaries was developed. Results comparison among the classic Terzaghi's one-dimensional consolidation theory, the analytical solutions of Terzaghi's one-dimensional consolidation equation with continuous drainage boundaries and the analytical solutions of one-dimensional consolidation for a double-layered ground to verify the correctness. According to the layered ground of practical engineering, one-dimensional consolidation problem with continuous drainage boundaries in layered ground was investigated by using changes in different elastic moduli, permeability coefficients and poisson's ratios with the finite element analysis. The results show that continuous drainage boundaries can simulate the practical engineering commendably. Source

Yan C.,Zhejiang University | Wu Q.,Wenzhou Architectural Design and Research Institute
WIT Transactions on the Built Environment | Year: 2013

In order to determine the relative dynamic modulus of elasticity and mass loss rate of concrete subjected to salt spray corrosion and seawater attack, a nondestructive detection method was adopted and a condition of marine salt spray and underwater area was simulated in this test. It is to investigate the damage evolutional law, characters and damage degree of concrete, and to compare the deterioration of concrete in the two kinds of environment. Based on the concept of damage degree, the influences of slag content and concrete strength on concrete damage degree were discussed in depth. The results show that the change tendency of the relative dynamic modulus of elasticity exhibits 4 stages, while mass loss change represents 2 stages. The deterioration of salt spray corrosion is more serious than that of seawater attack, the damage degree of concrete enlarges with the increasing of slag content and is greatly influenced by the concrete strength. © 2013 WIT Press. Source

Wu Q.-L.,Nanjing University of Aeronautics and Astronautics | Wu Q.-L.,Wenzhou Architectural Design and Research Institute | Yu H.-F.,Nanjing University of Aeronautics and Astronautics | Chen X.-X.,Wenzhou Medical College
ICCTP 2010: Integrated Transportation Systems: Green, Intelligent, Reliable - Proceedings of the 10th International Conference of Chinese Transportation Professionals | Year: 2010

Based on the damage failure criterion of concretes, the mass loss rate is introduced as a damage variable to describe the concrete damage. The mass loss characteristics and evolutional law of concretes subjected to corrosion or freezing-thawing conditions are investigated. The results show that mass loss of concretes can be represented by either a single-segment loss mode or a double-segment loss mode, and the typical mass loss curves include a straight line, a parabolic line and the combination of straight and parabolic lines. On this basis, a mass loss mathematics model, which can be universally applied, is established. Two new concepts, namely, mass loss velocity and mass loss acceleration, are brought forward for the first time. The physical meaning of these parameters are also theoretically clarified. Furthermore, the results of model prediction show that there is good agreement between measured data and predicted data, which indicates that the model behaves well to predict the service life of concretes. It provides a new method for service life prediction of concretes. © 2010 ASCE. Source

Cai J.-G.,Nanjing Southeast University | Yu L.-Z.,Wenzhou Architectural Design and Research Institute | Wang F.,Nanjing Southeast University | Feng J.,Nanjing Southeast University | Zhang C.-S.,Nanjing Design Institute of Civil Architectural
Tumu Jianzhu yu Huanjing Gongcheng/Journal of Civil, Architectural and Environmental Engineering | Year: 2010

Based on the discussion of the simulation for the cable prestress, the rigidity theory was used to identify the geometrical dimensions of semi-rigid structures in zero state. When the structural geometry in initial state is given, the geometrical dimension in zero state is determined by the initial prestress distribution. The contribution-matrix method is firstly applied to get the initial lack of fit. However, the influencing factor of initial lack of fit on the displacement of control point is linear superposition, that is, the structural response is linear, and it is irreconcilable with the geometry nonlinear of semi-rigid structure. In order to reduce the error of nonlinear structural response, the influencing factor in the contribution-matrix method is revised, and modified contribution-matrix method is put forward. Programs by ANSYS parameter design language APDL are worked out for the form-finding analysis of beam-string structure of a practical project. The numerical results show that the modified contribution-matrix method reduces the errors of the assumption of structural linear response. And it can be applied to the form-finding of semi-rigid structures with small stiffness. Source

Li J.,Zhejiang University | Xie X.,Zhejiang University | Zhang Q.,Wenzhou Architectural Design and Research Institute | Fang P.,Zhejiang University | Wang W.,Zhejiang University
Journal of Performance of Constructed Facilities | Year: 2014

A high-rise building with pile-raft foundation suddenly experienced extraordinary settlements and seriously tilted after 6 years of use in Wenzhou, a city in southeastern China. Some investigations were conducted and several potential causal factors were analyzed to determine the cause of the distress. The results indicated that the inadequate bearing capacity of the pile foundation was the reason for the extraordinary settlement. Inappropriate structure type selection and structural arrangement made the building sensitive to earthquake-triggered loading and prone to tilt. Remedial measures were applied to address the causal factors identified. Because of the low bearing capacity of the pile foundation, unloading was first performed and then the pile foundation was strengthened using steel pipe piles driven by anchor bolts. To address the inappropriate structure type and arrangement, the building was retrofitted to resist earthquakes. Observation results showed that the remedial measures took effect and the settlement (and tilt) of the building was completely controlled. © 2014 American Society of Civil Engineers. Source

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