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Qin Y.,Tianjin University | Qin Y.,Johns Hopkins University | Chen Z.,Tianjin University | Han N.,Tianjin Urban Planning and Design Institute
International Journal of Steel Structures | Year: 2014

The through-diaphragm connection detail has been identified as a good choice for attaching HSS beams to concrete-filled rectangular tube columns in engineering applications. In this research program an analytical study was conducted to comprehend the behavior of this detail and develop the accompanying design guidelines. The experimental results are presented elsewhere. In this paper two analytical models were established to predict the shear stiffness and yield shear strength of the HSS beam and panel zone, respectively. Theoretical results based on the proposed model well agreed with the experimental data. Finally, design provisions were introduced to check the strength in the connections. © 2014, Korean Society of Steel Construction and Springer-Verlag Berlin Heidelberg.

He J.,North China Municipal Engineering Design and Research Institute | Liu Z.,Tianjin Urban Planning and Design Institute | Deng W.,Nanjing Southeast University
Wuhan Ligong Daxue Xuebao (Jiaotong Kexue Yu Gongcheng Ban)/Journal of Wuhan University of Technology (Transportation Science and Engineering) | Year: 2010

This paper studies the method of rationality evaluation of trip demand for urban citizens by using fuzzy logic theory. According to trip-demand time and space distribution characteristics of urban citizens, the peak-hour trip factor and saturation of road network were chosen as the evaluation indexes, meanwhile the index calculation formulas were given; then on the basis of fuzzy logic theory and index characteristics, the membership functions were established by using fuzzy logic toolbox of MATLAB, and the evaluation results of two indexes were analyzed; Finally, the evaluation process was illustrated by a case study of Yangzhou and the results indicated the validity and practicability of the method presented in this paper.

Xu Z.,Tianjin Urban Planning and Design Institute | Xu Z.,Beijing University of Technology | Yang X.K.,Beijing University of Technology | Zhao X.H.,Beijing University of Technology | Li L.J.,Beijing University of Technology
Journal of Transportation Engineering | Year: 2012

This paper presents results of an exploratory study on differences in driving characteristics between normal and emergency situations and builds up the car-following model under the emergency evacuation situation. The simulation scenario has been given to create a driving environment under the emergency evacuation situations. Questionnaire investigations and the electrocardiogram/heart rate monitor are used to verify the validity of the driving environment from both subjective and objective perspectives. Perception reaction time (PRT) and the critical headway are taken as two indicators to describe driving characteristics. The results show that PRT is in accord with normal distribution under both normal and emergency situations. The value of PRT under the emergency situation is lower than that under the normal situation. The results also show that critical headway under the emergency situation is smaller than that under the normal situation. A back propagation (BP) neural network is designed in this study. A combination of the Levenberg-Marquardt BP algorithm and Bayesian regularization is employed to train the network. Gray-correlation analysis is conducted to determine which factors have a great impact on the acceleration of the following car. Simulation of the BP neural network using data collected from driving simulator reveals that the BP neural network has a high precision in the prediction of the car-following model. © 2012 American Society of Civil Engineers.

Deng Z.-D.,Tianjin University | Jiang X.-L.,Tianjin University | Han Y.,Tianjin University | Han N.,Tianjin Urban Planning and Design Institute
Gongcheng Lixue/Engineering Mechanics | Year: 2012

To study seismic behavior of new Tianjin library, a shaking table test of a 1/20 scale model is carried out for the main structure of the library. A steel frame-bracing system is employed in the main structure of the library. There are lots of removing columns and trusses with cantilevers in the interior structure with an irregular façade. Accordingly, this paper designs and products thoroughly the test model, including the selection of model material, the similitude-scaling relationship, the discussion for the model construction technology and design of test program. Finally, this paper lists the main result for the shaking table test.

Li C.,Tianjin Urban Planning and Design Institute | Li C.,Tianjin University | Li X.L.,Tianjin Institute of Urban Construction | Ji M.,Tianjin University | Liu J.,Tianjin University
Water Science and Technology | Year: 2012

Integrated fixed-film activated sludge (IFAS) is a modification of conventional activated sludge processes used for wastewater treatment consisting of biofilm attachment surfaces added to suspended-growth reactors, thereby creating hybrid suspended attached-growth systems. In this work, an IFAS system, with a total working volume of 560.7 L, was employed to investigate the performance of pollutants removal in industrial effluent. Microbial communities of suspended-growth and attached-growth biomass were investigated by a combination of polymerase chain reaction-denaturing gradient gel electrophoresis (PCR-DGGE) and fluorescence in situ hybridization (FISH). In the system, suspended-growth and attached-growth biomass worked together to maintain a stable COD, NH4 +-N and TN removal efficiency of 74, 93 and 76%, respectively. PCR-DGGE results showed that Proteobacteria was the dominant genera of bacteria in both the suspended and attached growth sludge. Some of the bacterial species (Firmicutes and Pseudomonas) may play an important role in the organic degradation of this water. Denitrifying bacteria were found to be accumulated in the biofilms. FISH results showed that there were more nitrifying bacteria in the suspended-growth biomass than the attached-growth biomass but fewer denitrifying bacteria in the former biomass. © IWA Publishing 2012.

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