Abstract:Due to the three dimensional force transmission mechanism, the application of pushover method for seismic response analysis of spatial structures is limited by the following issues: firstly, the representative nodal load displacement relationship can hardly be specified; secondly, there are no direct interrelationship among structural load, nodal displacement, and support reaction for spatial structures; thirdly, it is difficult to compute the capacity curves of spatial structures. In this paper, static elasto plastic analysis is carried out by using the load patterns generated from the structural vibration modes. Based on the overall stiffness parameter, the load displacement relationship of the modified equivalent single degree of freedom (ESDOF) system of each dominating mode, independent on support reactions, is obtained accordingly. And the equivalent mass of the modified ESDOF system is calculated by utilization of the mode period. Then the newly established ESDOF systems of the dominate modes are adopted in a modified modal pushover analysis (MPA) procedure. Numerical example shows that the modified MPA method, based on the overall structural stiffness parameter, overcomes the problem existing in the establishment of the structural capacity curve for the spatial structures. The computing consumption of the method given in this paper is 10% of the elasto plastic time history analysis (THA) method, meanwhile, in the seismic input direction, the nodal displacement data generated by the proposed method shows a 28% deviation compared with the THA method.

Abstract:In order to resist torsion effect to improve the stress state in curved box girder bridges, the torsion resistant design method of applying external tendons without increasing tendons is proposed. Based on the space analytic geometry relationship, the externally prestressing torsion calculation formulas are derived out. The torsion resistant design process of applying external tendons is presented with the objective of minimizing torsion. The optimal parameters of horizontal alignment of tendons are solved with non linear optimization method at the end of the process. The results indicate that the reasonable space layout design of external tendons instead of internal tendons significantly reduces peak torsion, and has almost no impact on the bending and shearing capacity. Comparison with the finite element analysis shows that the numerical results calculated by the formulas agree well with the finite element analysis, therefore the formulas can be a simple approach for practical design.

Abstract:Reinforced concrete bridges withstand both environmental erosions and fatigue loads during operations, resulting in the bridge carrying capacity decay. Through the analysis of the process of steel bar corrosion and fatigue damage, a damage calculation model is set up for evaluation of the comprehensive damage of steel bar’s cross section.Calculation of the hollow plate beam shows that corrosion of steel bar caused a significant reduction in its fatigue life. Therefore, the damage calculation model can provide the basis for the evaluation of the bridge’s time variant load capacity by the coupling effect of both bar corrosion and fatigue damage.

Abstract:Stud connectors are over densely arranged in steel concrete composite bridges in some cases. To address this issue, shear behavior of stud connectors with the diameters of 22mm, 25mm and 30mm were experimentally studied. Based on the test results, the failure model, shear strength, shear stiffness and slip capacity of large diameter studs (25mm and 30mm studs) were compared with those of normal diameter studs (22mm studs). In addition, the applicability of the design equations specified in existing codes to large diameter studs were evaluated. The results show that compared with 22mm studs, the average shear strength of 25mm and 30mm studs increase by about 14% and 42%, respectively, and the shear stiffness increase by about 35% and 106%, respectively. The design equations specified in Chinese Code (draw), Eurocode 4 and AASHTO LRFD give conservative predictions for the large diameter studs, and Eurocode 4 gives the most conservative values. The ratio of the measured value to the calculated value decreases as the stud diameter increases.

Abstract:An independent cover based manifold method (ICMM) is presented. In the ICMM, various high order cover functions can be naturally employed at the independent covers, and the springs with real physical significance are defined between the adjacent independent covers, which are different from the virtual springs in DDA(Discontinuous Deformation Analysis) and DEM(Discrete Element Method). The requirement for the complex algorithm for cover generation in conventional NMM(Numerical Manifold Method), and the rank deficiency due to the linear dependence of the global degrees of freedom in high order NMM are well treated in the present ICMM. The continuous deformation analysis, the discontinuous deformation analysis, and the switch from continuous analysis to discontinuous analysis can be unified in a same framework in the ICMM. Several test examples indicate the correctness and the validity of the proposed method.

Abstract:By taking the pile penetration as the expansion of a cylindrical cavity under the undrained condition and assuming small strain deformation in the elastic region and large strain deformation in the plastic region, the lateral displacement of ground due to a single pile installation is derived in modified Cam clay critical state soil. Meanwhile, the difference between the traditional overconsolidation ratio and the isotropic overconsolidation ratio is taken into account. Comparison between the predicted and the measured values from literature verifies the validity of the present solution. Furthermore, the proposed solution is developed to estimate the lateral displacements due to a single row of piles based on the assumption that superposition is applicable to the displacements. The effects of the number of piles, space of two adjacent piles, prebored hole and the overconsolidation ratio (OCR) on the calculation of displacements are conducted. The results show that the value of the displacement increase with the increasing piles number, and decreases with the increasing space of two adjacent piles and radius of prebored hole. The increase of OCR also leads to increase of displacement, however, that is not pronounced.

Abstract:To guild a reasonable pedestrian distribution in high rise commercial space is one of key problems in the design of high rise commercial complex. Pedestrian distribution in two rail transit commercial complex in Shanghai was studied by spatial configuration analysis with spatial syntax software and quantification of function and space (relationship with building entrances, distance to escalators, level, passage width and so on). Additionally in an attempt to integrate function with spatial configuration, two combination variables, spatial coefficient of function and spatial depth coefficient of function, were proposed, and SPSS(Statistical Product and Service Solutions） software was used to perform multiple regression analysis for pedestrian distribution. The analysis result reflects: ① space choice behavior has a certain rule in high rise commercial space, and customers’ purposiveness, function and space factors determines the flow distribution; ② comprehensive analytic model developed by spatial depth coefficient of function, space depth，relationship with building entrances, and distance to escalators, can well interpret flow distribution in high rise commercial complex and its determination coefficient can be up to 71.6% and 78.2%.

Abstract:Under the guidance of walkable city, this paper discussed the relationship between walking and location of daily community facilities based on the using characteristics of these facilities by walking including use frequency, use variety and distance decay function. Then this paper drew methodology of walkability evaluation, developed a computer assisted evaluation system, took New Jiangwan Town as a study area to carry out the evaluation system, and concluded a layout suggestion of facilities with high walkability score.

Abstract:Full scale tests of two kinds of epoxy asphalt pavement structure were carried out using MLS66 accelerated pavement test system at a test section of military airport. Considering high temperature environment, the pavement was heated to 60℃. Dynamic response characteristics was studied under the epoxy asphalt layer and asphalt concrete layer of two pavement structures. Dynamic response of epoxy asphalt layer is in the alternative state of tensile strain and compressive strain at the beginning of the loading, but is the tensile strain for semi rigid base pavement and is the compressive strain for semi rigid base pavement at middle and later periods of the loading. Asphalt concrete layers are predominantly compressive strain. Response analysis shows that mechanical behavior and state of pavement changed with the increase of loading times because of viscoelastic and rheological property of bitumen under the high temperature condition; Different mechanical response of epoxy asphalt pavement structural bring about different failure mechanism under high temperature condition, thus design control indexes are also different. Compressive strain should be controlled for composite pavement and tensile strain should be controlled for semi rigid base level.

Abstract:In order to detect the traffic incidents occurred on highway and reduce the loss brought by traffic incident, this paper presents an improved BP_AdaBoost algorithm based on genetic algorithm for traffic incident detection. The inputs of BP（Back Propagation）neural network value are vehicle quantity, velocity and occupancy in upstream and downstream of highway. Genetic algorithm is used for each BP neural network classification model for optimizing weights and thresholds due to its performance of global searching. The optimized BP neural network model is applied as a new weak classifier，then through the AdaBoost algorithm，many of these new weak classifier is composed as strong classifier model．This improved algorithm is validated with real data from Tokyo expressway ultra sonic sensors. The experimental results show that the algorithm can improve the performance of BP weak classifier. The detection rate of improved BP_AdaBoost algorithm is up to 97%, and false alarm rate is lower to 3.34%. Experiment indicate that the algorithm is suitable for detecting highway traffic incidents.

Abstract:Age, gender and luggage laden are selected as three factors of pedestrian individual characteristics. The influences of the three factors on personal space occupation and walking speed are analyzed. Accordingly the influence of the three factors on pedestrian maximum volume is studied by using the Legion simulation tool. The results show that age, gender and luggage laden have different influence on pedestrian maximum volume. With the increase of individual age, the maximum volume keeps the trend of decrease, especially the elderly pedestrian flow decreases by 23%~30% compared with the youth. The gender, however, has less influence, which is within 10%. The maximum volume has a remarkable reduction as the size of the luggage increases. The maximum volume of pedestrian flow carrying small luggage decreases by 35% compared to the pedestrian flow without luggage. Similarly, the pedestrian flow with medium luggage has a 60% reduction and the flow with large luggage has a 75% reduction compared to the pedestrian flow without luggage. Findings of this research are expected to enhance the knowledge of the relationship between pedestrian individual characteristics and pedestrian flow, and to be valuable for determining the capacity of facilities with different pedestrian compositions.

Abstract:Vehicle stability criterion is the basis of vehicle stability controls and decides the control intervention time and exit time. A phase plane method based criterion combing the sideslip angle method and the yaw rate method is proposed, which can coordinate the control of both vehicle sideslip angle and yaw rate. By means of phase plane method the data bases of the stable region thresholds are obtained, which contributes to establishing look up tables of the thresholds for real time control. Deviation functions of the sideslip angle and the yaw rate are designed to indicate the deviation between vehicle actual states and the reference states. Meanwhile, relative positions of the vehicle states and the stable region boundaries are also described by the deviation functions. When the vehicle states are beyond the stable region, the vehicle stability control should intervene timely to make the vehicle back to stable state.

Abstract:Till now, four main frictional squeal mechanisms are highlighted including negative frictionvelocity slope theory, mode coupling theory, spragslip motion theory and stickslip motion theory. However, none of them can explain various frictional squeal phenomena fully. So it is very important to make clear the relationship among various mechanisms in order to unify the realization of friction induced vibration and noise. A nonlinear friction induced vibration lamped parameter model with two degree of freedoms is established, to simulate the friction induced vibration behaviour between a flexible body and a rigid body frictional pairs with singlepoint contact based on friction coefficient and frictionvelocity slope. By deduction and calculation, effect of friction coefficient and frictionvelocity slope on mode coupling instability is studied, according to which instability characteristics are summarized in four areas. For each area, stickslip motion, limit cycle and their dependence on working conditions are investigated. At the same time, it is pointed out that the change of system parameters result in the occurrence of Hopf bifurcation under the condition of positive frictionvelocity slope.

Abstract:Traditional identification methods of vibration system characteristics are not capable to process nonlinear and non stationary signal,especially the low precision for identifying the damping ratio.An approach to identify the characteristics parameters of vibration system combining on random decrement technique and Morlet wavelet transform is proposed. Firstly, the free decay vibration response signal was extracted by random decrement technique(RDT), and then signal was processed to give a continuous wavelet transform by the Morlet wavelet transform to get wavelet energy spectrum.Combined the basic theory of parameter identification and semi logarithmic and curve fitting result in time frequency coordinate plane, frequency and damping ratio of the vibrating system was got.The numerical simulation result that the proposed method can accurately estimate system natural frequencies and damping ratios. The method was applied for experimental study of tanker liquid solid coupling model, the natural frequency and damping ratio of vibration system structure in loaded water conditions were well identified.

Abstract:Based on the traditional objective evaluation of vehicle fuel economy and WOT (wide open throttle) performance, the objective characterization of vehicle drivability were proposed, emphasizing on the four main aspects: POT (partial open throttle) response, accelerator pedal feeling, gear shift smoothness and tip in/tip out transient response characteristics. The objective characterization metrics including longitudinal acceleration response map, accelerator pedal acceleration linearity, acceleration gain, shock, acceleration RMS (root mean square), VDV (vibration dose value), etc. were investigated, and the consistencies of objective indicators and subjective evaluations were verified through correlation analysis. The fuel economy, performance and drivability comprehensive evaluation system was established based on multi objective balance. A diesel vehicle equipped with 6 automatic transmission was studied as an example, the vehicle and powertrain models were created based on AVL CRUISE software, and the economical and comprehensive shift strategies were generated based on AVL GSP (gear shifting program) tool, then the fuel economy, performance and drivability were contrasted and analyzed between different shift strategies, the effectiveness and practicability of the objective evaluation system were illustrated quantitatively.

Abstract:Based on entransy theory, the entransy balance equation and the entransy dissipation of blast furnace stave are obtained. On this basis, the thermal resistance of blast furnace stave is defined. According to the principle of minimum thermal resistance, thermal resistance is proposed to evaluate the heat transfer performance of blast furnace stave. The calculation method of the thermal resistance of blast furnace stave is illustrated with a practical problem. The relationship of maximum temperature of the stave hot face and thermal resistance with different cooling pipe space is compared. The results show that with the change of cooling pipe space, maximum temperature of the stave hot face and thermal resistance have the same trend. Under the certain boundary conditions, the heat transfer performance of blast furnace stave can be evaluated by the thermal resistance.

Abstract:Based on the characteristics of each microsource, the black start capability of microsources is researched and Bayesian decision method is applied to optimize the selection plan of black start primary reference source under different initial conditions. The models of microturbine, battery, solar and wind power generation are built in MATLAB/Simulink platform. By the simulation results, the black start capability of each microsource is compared and the feasibility of Bayesian decision method is validated. The results show that the microturbine and battery are good black start sources in microgrids due to their excellent capability of power output and the stability of voltage output. Photovoltaic power generation and wind power generation influenced by the outside environment are not suitable as black start sources.

Abstract:An improved particle filter method for pedestrian tracking in infrared video is proposed. The objects are described in the scheme of particle filter using Histogram of Oriented Gradients(HOG). Instead of the Euclidean distance in color space, the HOG is employed to describe the similarity and compute the weights of the samples, which solves the issue of lack of color information for infrared video. Experimental results show that the method is more accurate and effective tracking of moving targets in complex scenes than traditional particle filter algorithm in infrared video.

Abstract:Focusing on the extraction and description of common information between heterologous images, this paper proposed an algorithm for matching suitability analysis between heterologous images based on Sketch Token middle level features. Supervised learning has been used to acquire priori knowledge of homogeneous information between heterologous images, and utilize this knowledge to train the Sketch Token classifier, which is designed as a descriptor of homogeneous information to extract features on reference images. The statistical of extracted features is applied for training support vector machine classifier, which is used to analysis the matching suitability of reference images. The algorithm is validated by the satellite SAR(synthetic aperture radar) images which have been used as reference images and aerial RAR(real aperture radar) images which have been used as real images. The test result demonstrate the effectiveness of the algorithm.

Abstract:The troposphere decorrelation method was proposed, which can effectively decrease the correlation of tropospheric parameter and height of single epoch, thus realizing the efficient decouple of height and tropospheric delay and then the millimeter RTK （real time kinematic) results. In this paper, we evaluate the performance of 4 RTK methods by using 11 baselines with baseline lengths from 23 km to 90 km from Shanghai Continuously Operation Reference Station (CORS) network, including the single epoch least squares solutions with and without tropospheric delays, the kinematic Kalman filtering solution and the troposphere decorrelation solution. We highlight the analysis of RTK performance from the troposphere decorrelation method. The numerical experiments indicate that the millimeter accuracies can be obtained for all three coordinate components in the RTK solutions by the troposphere decorrelation method.

Abstract:Comprehensively using the Data Envelopment Analysis (DEA) based Malmquist index method, the β convergence testing model and the grey relational analysis process, this paper establishes a framework for measuring the total factor productivity (TFP) growth index as well as analyzing the growth convergence and related impacting factors, and uses the framework to empirically investigate the growth characteristics and impacting factors of TFP growth in the Chinese construction industry during the period 1993—2012. The findings show that the average annual TFP growth rate during this period is 4.6%, which is principally driven by the technological change, and that the technological efficiency does not increase substantially. It is also shown that there are significant differences among the changes of TFP during different sub periods. The growth rate reaches its highest level during the period 2004—2007, and then gradually decreases. β convergence tests indicate that there are significant convergences among the TFP growths in the national wide and eastern and central parts of China. The convergence of TFP growth in Western China, however, is not found to be significant. Factors in the areas of economic environment, industry research and technology capability, and industry structure could influence the growth of TFP, and the output percentage index of foreign funded construction enterprises is found to possess the highest grey relational grade with the TFP growth index.

Abstract:Aimed at implementing the rational modular partition and scientific evaluation, design structure matrix (DSM) theories and technologies were adopted to establish the evaluation and optimization methodology for city infrastructure multi projects integration control system, encompassing the algorithm of independent intensity and number, propagation cost, clustered cost etc. In terms of the system update, the genetic algorithm was combined with the clustering algorithm of DSM so as to achieve the most optimal update scheme. Changchun infrastructure multi projects integration control system was selected as the typical case, two versions of which before and after updating respectively were compared on degree of modularity and an update scheme for next generation had been put forwarded. The results verify the feasibility and effectiveness of the proposed methodology on modular partition, schemes evaluation and optimal selection, which provide theoretical and practical references for the development and maintenance of large integrated control system of the same kind.

Abstract:The contract design problem under asymmetric production cost disruption information in a dual channel supply chain composed of one manufacturer and one retailer is investigated. By utilizing the principal agent theory and solving the Kuhn Tucker conditions of the optimization problem, the optimal contract under asymmetric production cost disruption information are derived. Moreover, the impact of asymmetric production cost disruption information on the dual channel supply chain’s optimal pricing, the production quantity decision and supply chain members' profit and the whole system performance of the dual channel supply chain are analyzed. It is found that the original production plan is still optimal under some specific conditions, asymmetric production cost disruption information does not necessarily cause profit loss for the system. And the conditions under which the asymmetric production cost disruption information will not cause profit loss to the system are also explicitly presented.

Abstract:By using Super efficiency DEA Model to analysis the survey data of Shanghai 6 816 emerging industries enterprises, the empirical analysis, by the micro perspective, aimed to compare with different forms of ownership efficiencies of technological innovation, and to explore the deep reasons of such differences. The research shows that: Efficiencies of technological innovation obviously vary in different forms of ownerships, among which, the private owned companies have the high efficiencies of technological innovation; the private partnership owned and other 12 forms have the medium efficiencies; the Sino foreign joint and other 5 forms have the low efficiencies. The foreign and the Sino foreign joint are both inefficient while the private owned generally have the high efficiencies. The solely state owned, collectively owned, the state owned and the foreign owned all have redundancy on governmental R&D subsidies but they do not fully use them.