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Quan Y.,Tongji University | Chen B.,Hangzhou Municipal Facilities Supervision and Administration Center | Gu M.,Tongji University | Tamura Y.,Tokyo Polytechnic University
Gongcheng Lixue/Engineering Mechanics | Year: 2010

By using a method for estimating extreme value of non-Gaussian wind pressure proposed by the authors, the wind pressure measurement wind tunnel test data in the aerodynamic database for low-rise buildings in Tokyo Polytechnic University in Japan are processed and the effects of geometrical parameters on the most unfavorable negative wind pressure coefficients on the gable roof of low-rise buildings are studied. Some new and detailed conclusions are drawn from the results. The roof pitch has great effects on the values and locations of the most unfavorable wind pressure coefficients of gable roofs. The aspect ratio of building has smaller effects on the most unfavorable wind pressure coefficients. In most cases, the most unfavorable wind pressure coefficients increases slightly with the increase of the aspect ratio. The side ratio has less influence on the values and furthermore the influence regularity is weak. Source


Chen B.,Zhejiang University | Li X.,Zhejiang University | Xie X.,Zhejiang University | Zhong Z.,Hangzhou Municipal Facilities Supervision and Administration Center | Lu P.,Zhejiang University of Technology
Shock and Vibration | Year: 2015

In the through arch bridges, the suspenders are the key components connecting the arch rib and the bridge deck in the middle, and their safety is an increasing focus in the field of bridge engineering. In this study, various vehicle traffic flow parameters are investigated based on the actual vehicle data acquired from the long-term structural health monitoring system of a composite arch bridge. The representative vehicle types and the probability density functions of several parameters are determined, including the gross vehicle weight, axle weight, time headway, and speed. A finite element model of the bridge structure is constructed to determine the influence line of the cable force for various suspenders. A simulated vehicle flow, generated using the Monte Carlo method, is applied on the influence lines of the target suspender to determine the stress process, and then the stress amplitude spectrum is obtained based on the statistical analysis of the stress process using the rainflow counting method. The fatigue performance levels of various suspenders are analyzed according to the Palmgren-Miner linear cumulative damage theory, which helps to manage the safety of the suspenders. © 2015 Bin Chen et al. Source


Chen B.,Zhejiang University | Zhong Z.,Hangzhou Municipal Facilities Supervision and Administration Center | Xie X.,Zhejiang University | Lu P.,Zhejiang University of Technology
Mathematical Problems in Engineering | Year: 2014

Significant changes in vehicle loads have occurred in China due to the development of the automobile industry and transportation within the past two decades, particularly the rapid increase in traffic flow and the large-scale emergence of heavy trucks. However, research into vehicle loadings on urban bridges is not well developed. In this study, based on traffic flow data collected using a weigh-in-motion system installed on an expressway in an urban logistics zone, we analyzed the traffic flow, vehicle types, and gross vehicle weight (GVW) features and developed models for the vehicle load and fatigue load. According to the axle space, axle types, and axle number, the trucks in the traffic flow were classified into 10 representative vehicle types. The probability distribution of the GVW was fitted to a three-class mixed log-normal distribution. Using the improved Gumbel method, we determined the extreme value distribution of the vehicle loadings in the purpose reference period and assessed the vehicle loadings of urban bridges. In addition, using the equivalent damage theory, six equivalent vehicle models were established according to the measurements of the axle weight and axle space, thereby obtaining a simplified model of fatigue vehicle loadings on urban expressway bridges. © 2014 Bin Chen et al. Source


Zhong Z.,Hangzhou Municipal Facilities Supervision and Administration Center | Wen J.,Hangzhou Municipal Facilities Supervision and Administration Center | Chen B.,Hangzhou Municipal Facilities Supervision and Administration Center | Chen B.,Zhejiang University | Jin L.,Hangzhou Municipal Facilities Supervision and Administration Center
Modern Tunnelling Technology | Year: 2014

Shield tunneling passing though an existing pedestrian with a short distance has adverse effects on the stress state of underpass by resulting in loosing below its floor. And if effective measures are not taken, it will be further damaged. Taking the construction of a newly-built tunnel as an example and based on the mechanical characteristics of underpass, this paper put forward steel frame reinforcement inside the underpass and soil body reinforcement below the underpass for enhancing the vertical and horizontal stiffness of underpass and improving the bearing capacity and strength of soil body; and the stress states of underpass under five working conditions are simulated with 3D model established by finite element software. The results show that with these targeted reinforcements, the stress state was effectively improved with the maximum force reduction up to 70% and the adverse effect induced by shield tunneling was reduced to an acceptable level. ©, 2015, Editorial Office of "Modern Tunnelling Technology". All right reserved. Source

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