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Zhang D.,Harbin Institute of Technology | Dong Y.,Huaqiao University | Wu Y.,China CTDI Engineering Corporation
Huazhong Keji Daxue Xuebao (Ziran Kexue Ban)/Journal of Huazhong University of Science and Technology (Natural Science Edition) | Year: 2012

An improved virtual work method was proposed to calculate the ultimate load-carrying capacity of one-way concrete slabs under uniformly distributed load at large displacements, and its derivation was based on the classical yield-line theory. The work, which caused by the extension of steel reinforcements at the sections of plastic hinge line under large displacements, was added in the method. Six one-way slabs with three types of edge conditions were tested to validate the method. Then the theoretical predictions by the method were compared with experimental results. It is shown that the failure mode of the test slabs subjected to large displacement is almost identical with that assumed in the classical yield-line theory. The slabs can carry test load steadily due to the tensile membrane action, even when their displacements reach 1/15 of the span-length. The predicted load-carrying capacity of the method is no more than 10% error compared with the test results, and it shows good accuracy.

Shi Y.,China CTDI Engineering Corporation | Li H.-W.,Taiyuan University of Technology | Chen Y.-Y.,China CTDI Engineering Corporation | Zhong H.-P.,China CTDI Engineering Corporation
Applied Mechanics and Materials | Year: 2013

In this paper, elasto-plastic dynamic response analyses of 300m span arch truss's structure model are carried out under the condition of earthquake by using SAP2000. The geometric and material nonlinear effects are considered. Based on the plastic-hinge theory, by gradually increasing the peak acceleration of earthquake, the structure's dynamic elasto-plastic analysis have been done with Ninghe wave under the initial condition that the arch truss's stress and strain are caused by constant load and snow. According to simulation results, the critical peak acceleration is obtained when the steel framework lose stability, which can judge the anti-seismic capacity of the structure. © (2013) Trans Tech Publications, Switzerland.

Liu Y.,Chongqing Jiaotong University | Li J.,Chongqing Communications Engineering | Fu Y.,China Ctdi Engineering Corporation
Advanced Materials Research | Year: 2012

The cement stabilized macadam mixed with different admixture influence the vibration compaction effect, under certain aggregate gradation and vibration parameters, carry out vibratory compaction and compaction tests on cement stabilized macadam with incorporation of different admixture and cement dose of 4%, test results show that: when single mix water-reducing agent, adding 1.0%, cement stabilized macadam most easily compacted; when single mix fly ash, the mixing 30%, cement stabilized macadam most easily compacted; when compound mixed with fly ash and water-reducing agent, help reduce optimum water content, increasing the maximum dry density compared with single mix water-reducing agent or fly ash, and water-reducing agent dosage is 1.0%, fly ash dosage is 20% are the best. © (2012) Trans Tech Publications.

Zhou C.,Chongqing University | Chen C.,China CTDI Engineering Corporation | Ren H.,Chongqing University
Applied Mechanics and Materials | Year: 2013

According to constraint elements more and more appearing in the comprehensive forms, and at present it only considers that single constraint element of city underground space development and utilization has been unable to reflect the actual situation. On the basis of the main characteristics of city underground space development and utilization, this paper aims to analyze various factors which may cause the consequence and the frequency of appearance, and to construct evaluation index system of city underground space development and utilization which is composed of 5 one-level indexes, 20 two-level indexes of evaluation index system of multiple constraint factors of city underground space development and utilization, and to use the analytic hierarchy process and fuzzy comprehensive evaluation method to analyze and evaluate the influence on city underground space development and utilization. Analysis of the example application shows that, it only considers single constraint element of city underground space development and utilization is not comprehensive, and not science, and it needs to consider the correlation between various constraint elements. © 2013 Trans Tech Publications Ltd, Switzerland.

Wu G.X.,Chongqing Jiaotong University | Li Q.J.,Chongqing Jiaotong University | Cheng G.Y.,China CTDI Engineering Corporation
Applied Mechanics and Materials | Year: 2013

A road's ecological environmental quality index data for years is a time-series, and accurate prediction by exploring the changing rule of the time series is significant for future environmental protection. For this end, based on time series analysis, this paper firstly carries out steady analysis and random test pretreatment for the eco-environment quality index (EQI) data collected. Next, an ARMA model is established by pattern recognition, established bands and parameter estimation, and then verified by the data collected in recent years. Finally, the ARMA model is used to predict the future EQI values. This research will provide effective guidance to the eco-environmental protection along the road. © (2013) Trans Tech Publications, Switzerland.

Liu M.,Chongqing University | Qian F.,Chongqing University | Zhan X.,China CTDI Engineering Corporation
2010 International Conference on E-Product E-Service and E-Entertainment, ICEEE2010 | Year: 2010

To establish an analytic model for carbon emission of building lifecycle, based on life cycle theory and the factors affecting energy consumption in building material transportation(BMT), a calculation method for carbon emission benchmark of BMT was proposed. Furthermore, with the coefficient of carbon emission by transportation means and the coefficient of transportation distance, a calculation model for carbon emission of BMT was put forward. Taking steel as a case study, it is found that the benchmark of carbon emission from steel transportation is 15.86 kg/t steel. Railway transportation is the cleanest way, accounting for one tenth of that of highway and a half to one third of that of waterway. ©2010 IEEE.

Jiang Y.,Chongqing Jiaotong University | Bai H.,China Ctdi Engineering Corporation
Applied Mechanics and Materials | Year: 2012

The basic theory of fast multipole virtual boundary element method (VBEM) is discussed through expanding the fundamental solution, and the algorithm can make the complexities of operation and memory about solution of the equations to be of linear proportion to the freedoms of the problem. Numerical examples are presented to demonstrate the feasibility, accuracy and efficiency of the method. At the same time, the relationships between the order for expansion and the storage capacity, computing time, precision are analyzed, and the influence of boundary points in the leaf to the calculation efficiency is discussed. The corresponding reference value is put forward for the convenience of engineering application. © (2012) Trans Tech Publications.

Luo W.,Chongqing University | Li Y.,Chongqing University | Zheng N.,Chongqing University | Chen N.,China CTDI Engineering Corporation
Applied Mechanics and Materials | Year: 2012

In order to improve the seismic behavior of the rural masonry buildings and reduce the cost and be convenient for construction, a precast tie-column system was put forward, which was suitable for masonry buildings, constructed by fired common bricks or porous bricks. The uniaxial compression constitutive relation of brick masonry was used for simulating the precast tie-column. And this paper analyzed the difference of the seismic behavior of masonry walls which bearing different vertical compressive stress, and confined by cast-in-place tie-columns or precast tie-columns, and whether contain windows or not. The results show that the uniaxial compression constitutive relation used for simulating precast tie-column is reasonable and the seismic behavior of masonry walls confined by precast tie-columns is better than the wall without tie-colums, and equal to those confined by cast-in-place tie-columns. © (2012) Trans Tech Publications.

Yang H.,Chongqing University | Zhang L.,Chongqing University | Zhang H.,China CTDI Engineering Corporation
Jianzhu Jiegou Xuebao/Journal of Building Structures | Year: 2013

Flexibility method based fiber model could calculate strong material nonlinear hysteresis responses of reinforced concrete columns more efficiently, but the accuracy of numerical simulation for the capacity of column at later soften phase after peak will be obviously decreased if buckling and fatigue damage of longitudinal reinforcing bar were not considered in the constitutive model. Based on the seismic behavior experimental results of eight reinforced concrete columns, the hysteresis nonlinear responses of the columns were simulated by adopting constitutive model including buckling and fatigue damage of bar and flexibility method based fiber model within the OpenSees platform. The results show that, with respect to the column of small axial force ratio, namely the ratio of axial force to column sectional area and compressive strength of concrete, the influence of bar buckling on the strength degradation after peak capacity of the high axial force ratio column is obviously greater. For the column with slenderness ratio of longitudinal bar less than 3.0, the influence of bar buckling on the nonlinear analysis results can be basically ignored. In the case of the column with slenderness ratio being 5.00 to 8.75 and axial force ratio being small, buckling have certain effect on the analysis result, but better analysis results of strength degradation characteristics of column at softening phase can be obtained if fatigue damage is considered. For the column with axial force ratio being high and slenderness ratio being 6.25 to 7.00, both of buckling and fatigue damages will evidently decrease the analysis error of strength degradation. Considering buckling and fatigue damages simultaneously is found to be beneficial to obtain better simulation results of strength degradation characteristics of column.

Ren H.,Chongqing University | Yan Y.,Chongqing University | Zhou T.,Chongqing University | Xiang X.,Chongqing University | Zhang Y.,China CTDI Engineering Corporation
Tumu Gongcheng Xuebao/China Civil Engineering Journal | Year: 2011

The key part of establishing organization coalition for mega projects is to rationally select strategic partners, and evaluation of potential partners quickly and accurately forms an important basis to select partners and to establish organization coalition. According to the fuzzy and random features in the evaluation of cooperative partners for organization coalition, this paper employs a cloud model and the uncertain inference, translates the qualitative appraisal of potential partner's factors into quantitative scores to achieve the effective transition from a linguistic term of a qualitative concept to its numerical representation. Furthermore, the method of evaluating cooperative partners for organization coalition of mega projects based on cloud model and gray correlation analysis is proposed by using gray relationship theory. Through example analysis, it shows that the method has relatively strong feasibility and effectiveness.

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