Abstract:This paper investigates behaviours of restrained column in a fire using a calibrated finite element model. Studied parameters included axial load, bending moment load, axial restraint stiffness, rotational restraint stiffness, slenderness and end moment ratio. Presented results include the column axial force-temperature and bending moment-temperature evolution curves, critical temperature of restrained column, difference between critical temperatures of unrestrained column and restrained column, and difference between critical temperature and buckling temperature of restrained column. Results of parametric study show that: (1) before the column buckles, the axial force in column increase linearly and bending moment changes a little; (2) after the column buckles, the column is loaded under combined axial force and bending moment; (3) the axial restraint reduces the critical temperature of restrained column; and the reduction in critical temperature increases with increasing in axial restraint stiffness. However, when the axial restraint stiffness ratio is higher than a certain value, no further reduction in the column critical temperature occurs.

Abstract:In the seismic response analysis of cable-stayed bridges, cables were generally modeled using single-element cable system (SECS model), which can not simulate the local vibration of cables. In order to investigate the effect of cable vibration on seismic response of super-long span cable-stayed bridge, the Sutong Bridge, which is the longest span cable-stayed bridge in the world, was taken as an example, and its analytical model was established. In this model, cables were modeled with multiple-element cable system (MECS), and rational discretization manner was discussed. The results show that rational discretization manner is dividing each cable into 10 elements. Cable vibration change the dynamics characteristics of the whole bridge, especially cause the appearance of some cable-deck coupled modes, which cause the reduction of participation factor of some modes, the seismic forces of girder and tower are also reduced, especially the axial force of the tower. Furthermore, cable vibration makes the cables, whose frequency are close to vertical vibration frequency of the girder, vibrate seriously.

Abstract:A bounded Hrovat semi-active control strategy providing the adequate performance control of general stochastic dynamical systems is proposed in the present paper. It hinges on the generalized density evolution equation recently developed to reveal the intrinsic relationship between the physical mechanism and probability density evolution of systems. An earthquake-excited system controlled by a Magnetorheological (MR) damper is investigated for illustrative purpose, of which two parameters are laid down, i.e. damping coefficient and maximum Coulomb force, according to the criterion of system second-order statistics evaluation and perfectly tracing the optimal active control forces. Numerical results reveal that the appropriately designed semi-active controller can achieve almost the same effect of the active controller in the probabilistic sense. The example further proves that the advocated semi-active control strategy could prompt the dynamic damping performance of the MR damper, behaving as a type-like Bouc-Wen model with the strength deterioration, the stiffness degradation and the pinch effect.

Abstract:Based on the modal parameters of the structures, four damage states and the range of final softening index of each state are suggested in this paper firstly. Then, 9 hybrid structures with different structural characteristics are analyzed by structural analysis program CANNY for about 500 times subjected to different ground motions. So, the relationship of the maximum interstory drift and the main structural characteristics, as well as the final softening index is obtained. At the same time, the relationship between the maximum interstory drift and the maximum roof displacement over the height is also acquired. Based on the pushover analysis, a damage index of high-rise hybrid structures accounting for maximum deformation and cumulative damage is put forward. Finally, a case study is conducted on a high-rise hybrid structure model tested on the shaking table before, and verifies the quantities of damage indices suggested in the paper.

Abstract:Based on random vibration theory, a method is developed for wind induced lateral-torsion coupled response of structurally asymmetric tall buildings, in which the integrated effects of mode coupling and wind force correlations are also taken into account. Using the wind pressures data on rectangular tall buildings measured with a wind tunnel test, the coupled responses of the rectangular tall buildings are calculated. The effects of eccentricity location and side ratio are also examined for serviceability. The results indicate that the alongwind eccentricity between centers of mass and rigidity for a building whose windward breadth is shorter than it depth may result in a great increase in wind-induced responses.

Abstract:In the Incremental dynamic analysis (IDA), the intensity of one single ground motion is increasingly set according to a series of intensity measure (IM). The elasto-plastic dynamic analysis of the structure under different IM is then carried out to obtain the relationship between the structural damage measure (DM) and ground motion IM. When considering a set of ground motions, the analysis of DM-IM curves can be applied to evaluate the structural performance. IDA is thus seen as so-called “dynamic pushover analysis”. In this paper, the method of IDA was introduced and applied in a hybrid structure. The analytical process and results are helpful for the performance-based seismic design of hybrid structures as well as for the wide application of IDA in complex structures.

Abstract:In order to build an appropriate rheological model for brittle hard rock, a nonlinear viscous component whose viscous coefficient is decay function of stress and time was built. The viscous component of Bingham model was replaced by this nonlinear viscous component, thus, modified Bingham model was obtained. The nonlinear viscoelasto-plastic rheological model for hard rock was gotten by the combination of modified Bingham model with six-component linear viscoelastic model. This new nonlinear viscoelasto-plastic rheological model can study accelerated creep property. Finally, this new model was verified by using the creep test curve of sandstone from left bank slope at Jinping First Stage Hydropower Station. The research results show that the new nonlinear visoelasto-plastic rheological model curve and experimental curve approximately coinside with each other. Therefore, the new nonlinear visoelasto-plastic rheological model model is available and reasonable.

Abstract:Based on the field monitoring data of 32 deep excavations in Shanghai, the main characteristics of ground settlement have been summarized as follows. Firstly, most settlement profiles around deep excavations appear to be grooves with settling tanks. Secondly, the maximum ground settlement, , lies between 0.4 and 1.9 ( for the maximum lateral deflection), and its mean value is equal to . Thirdly, system stiffness of all deep excavations is great and its influence on is small. Fourthly, the maximum ground settlement decreases with the increase of the factor of safety against base heave (FOS), and the FOS-based settlement predictive curve is proposed at the same time. Finally, according to the character of measured settlement profiles in Shanghai, the author proposed a predictive method taking into account effect of the settling tank’s eccentricity. With the verification of the proposed method in four deep excavation cases, the results show a high degree of accuracy, which is proved to be a practical method in ground settlement prediction around deep excavation.

Abstract:For the purpose of research on carbonation regularity of concrete bridges, the durability experiments of forced concrete specimens in accelerated carbonation corrosive environments were carried out. The degradation mechanism of carbonized concrete structure was analyzed. The results show that tensile or compressive stress can accelerate or slow down carbonation rate, respectively. Larger changes of stress will cause larger changes of carbonation rate. The carbonation depth of bridge-common used C50 strength concrete is far smaller than low strength concrete but the relative carbonation depth of C50 strength concrete applied tensile stress is larger than low strength concrete. According to the tests, the working stress influence coefficient in existing concrete carbonation depth prediction model was modified. The crack in concrete bridges has little effect on concrete carbonation if its width can meet standard requirements, and the durable performance of prestressed concrete bridges is better than reinforced concrete bridges.

Abstract:Topology of intersection bracing members on the body of transmission tower is the key to determining structure’s total weight. In this paper, the problem of its optimization was solved in three steps: First, the ground structure’s nodes were got by Fibonacci search according to the characteristics ,that there was only one minimum when the total weight varieties with the number of nodes , so the ground structure was built; Second, a recursion procedure was proposed to find all the feasible topology schemes, and ant colony algorithm was employed to find the optimal one; third, node’s coordinates were optimized by sequence two-stage algorithm. Applications for three samples were presented, the topology of the intersection diagonal members and all the node’s coordinates were optimized, Key results include a new topology design and a certain mass reduction, and the result is practical in project.

Abstract:The 3-Dimention finite element model was founded and interface element was employed to simulate the characteristic of the interfacial agent at the jointing position, drawn the relationship curve between the characteristic parameter of the jointing interfacial agent and the critical adhesive strength, obtained the critical adhesive strength value of the jointing interfacial agent under symmetrical load, shows that the required critical adhesive strength decreases when the maximum opening displacement of the adhesive interface at failure point increases.

Abstract:In this study, the effects of temperature, vehicle speed, crack length and base type on the stress intensity factor (SIF) at the tip of top-down cracking in asphalt pavements under moving load were evaluated by conducting fracture mechanics and finite element (FE) analyses. Dynamic modulus master curves and time-temperature shift factors were incorporated into the FE model to characterize the mechanical properties of asphalt mixtures. The results show the peaks of tensile type SIF (KI) and shear type SIF (KII) increase as crack length increases and temperature decreases. Vehicle speed has significant influences on the frequency of SIF and slow traffic loading can accelerate the propagation of top-down cracking. The use of semi-rigid bases in asphalt pavements can reduce SIF compared to granular bases. The contribution of KI to the propagation of top-down cracking becomes less significant, while that of KII becomes more evident when temperature and crack length increase.

Abstract:This paper presents a novel lane detection algorithm, which is suitable for automatic drive system. The algorithm chooses the common curve lane parameter model, which can describe both straight and curved lanes. The most prominent contribution of this paper is: instead of using one single method to calculate all the parameters in the lane model, both the Adaptive Random Hough Transformation (ARHT) algorithm and the Tabu Search algorithm are used to calculate the different parameters in the lane model, according to the different demands of accuracy for different parameters. Furthermore, in order to reduce the time-consume of the whole system, the strategy of multi-resolution is proposed. At last, this paper also presents a tracking algorithm based on the particle filter, which can make the system more stable. The algorithms presented in this paper are proved to be both robust and fast by a large amount of experiments in variable occasions, besides, the algorithms can extract the lanes accurately even in some bad illumination occasions.

Abstract:In the previous studies of highway network topology, interchanges and exits/enters are always regarded as simple nodes without specific information about ramps. With the expansion of the network as well as the increase of the demand originating from analysis of security, design of traffic signs, emergency disposal, virtual reality simulation and vehicle navigation that are based on these topologies which are composed with the single-layer structure relationship, these topologies can no longer meet the requirements of these applications. On the other hand, they also lead to the best path search algorithm related becoming more complex. In this paper, a multi-level complex expressway network topology structure including information of interchange ramps is put forward according to the transportation engineering on the basis of research projects; it contains information of route/node, ramp/access and the direction of the node, meanwhile it can meet standard format of GDF (Geographic Data Files). It can support next-generation applications which are based on the complex expressway networks and the doubly linked list data structure is established to facilitate changes in the expressway interchange or the exits and enters unit. At the end of this paper, a new best path search algorithm is raised on the basis of the complex topology structure; it is possible using the complexity topology to adapt applications in future.

Abstract:Applying graphic developing tools of Halcon and OpenCV on VC++6.0 platform, background subtraction and region-based tracking algorithms are used to realize picking up and tracing the moving vehicle target, and the data is saved synchronously. Transacting the video data information, the track, velocity and the acceleration of conflicting vehicle is calculated respectively, and multi parameter based traffic conflict judging measure is setup. Thus the video-based vehicle conflict automatically detecting system for simple traffic environment is initially developed.

Abstract:3D road module, vehicle models database, and driver module were built in computer, and integrated into roadway– driver-vehicle simulation system. A forth class road in YunNan province in China was selected as analyzed course in our driving simulation, as well as a passenger car model, and a desired course of road center line, definition of driving behavior parameters considered over 70 percent driver in real word. Speed performance, complexity of the driving task, and comfort of driving and riding were respectively analyzed in this paper. The results show that, if consistency of design standard along road length was ensured, especially paying attention to control of straight sections length, lower class road with equilibrium speed also can be provided to road users; reverse loop and absent of spirals in lower class road would cause a high increases in peak value of steering wheel rev and change rate of lateral acceleration, which could lead drivers very flurry and riding uncomfortable; curve-based method should be attempt in alignment design more frequently, which seems to be the best solution to highway safety problems.

Abstract:The assessment model of Network level pavement performance was established by means of the fuzzy clustering method, which was based on gray correlative analysis among the pavement performance indexes of the component pavement units. The fuzzy equivalence relations were obtained. The maximum tree method was used, and the dendrogram was introduced on the basis of the different clustering level. Thus, the state of pavement performance can be demonstrated reasonably.

Abstract:The difference between China railway track irregularity statistic spectrums and abroad railway track irregularity spectrums is compared first, then, according to the track geometry data measured from Shanghai-Kunming and Jinhua-Wenzhou railways, PSD(Power Spectral Density) and TQI(Track Quality Index) are calculated with Matlab program. The results shows that the former track irregularity spectrum values are much smaller than the US class 6 railway’s, while the latter ones are close to the US class 5 railway’s. The coherence functions are utilized to analyze the relationship between track irregularities and vertical and lateral car body vibration accelerations. Together with car body vibration acceleration spectrum analysis, the conclusion that the range of detrimental track irregularity wavelengths has been drawn, thus providing theoretical and practical guidance for track maintenance and management. Furthermore, the paper calculates the integral of each track irregularity spectrum values. The results show that each TQI has a close relationship with each track irregularity spectrum area. Consequently, it proves the reliability of appraising the track quality with PSD analysis. Finally, the track irregularity spectrum is proposed to be one of the main indexes to control the track geometry for speed-up railway.

Abstract:A batch tests study was performed to evaluate the changes of heavy metal chemical speciation in sewage sludge with humus soil. Sewage sludge with humus soil (0, 0.5, 1, 2, 3, 5g) mix 20d in polyethylene flasks. The five stages of the Tessier sequential extraction method was employed to investigate changes in heavy metal fractions of Zn, Cu, Ni and Pb in sewage sludge with humus soil. The results showed that humus soil effected chemical speciation of heavy metals in sewage sludge significantly. Zinc: ion-exchange (F1) zinc, carbonate-bound (F2) zinc and iron-manganese oxide bound (F3) contents and HS dosage had significant negative correlation (0.9266, 0.9310, 0.9144, p<0.01), sulfides and organic-bound (F4) and HS dosage had a significant positive correlation (0.9304, p<0.01). Copper: F2 and HS dosage had a negative correlation (0.7145, p<0.05). Nickel: F1 and F2 nickel and HS dosage had significant negative correlation (0.9027, 0.9724, p<0.01), F4 nickel and residual (F5) and HS dosage had a significant positive correlation (0.9188, 0.9123, p<0.01). Lead: F3 and F4 lead and HS dosage had negative correlation (0.7027, 0.7635, p<0.05), F5 lead and HS dosage had a positive correlation (0.7668, , p<0.05). Adding humus significantly reduced the potential availability of zinc, copper, nickel, and lead in activated sludge.

Abstract:Magnesium oxychloride cement (MOC) was used in the sludge stabilization experiments as a new type stability agent in this paper. When the mass ratios of MOC/Sludge are 5/100-20/100, molar ratios of MgO/MgCl2 are 3/1-5/1, the highest compressive strength of stabilized sample can be achieved at 85.14 kg/cm2, the coefficient of permeability up to 2.17×10-3 cm/s, the plasticity index is as low as 7.9, and the grain size increases in linear. When the range of the sludge grain size gets to 45-72 μm, sludge specific resistance decreases sharply. XRD and SEM were used to characterize the macroscopic and microscopic effects of sludge caused by MOC. The results reveal that gelling and hydration reaction would be happened in the MOC-sludge system. Mg-Si-Al gel system is formed with Si2+, Al3+, Cu2+ in the sludge under alkaline condition. The hydrate can be seen and it plays an important role in the sludge stabilization.

Abstract:The mobilization theory of aquifer particles induced by groundwater heat pump(GWSHP) pumping is theoretically studied in this work, which includes analysis of forces working on the particles and the releasing mechanism. A case study, which represents a kind of typical aquifer in Tianjin, is carried out. Such parameters as water discharge, aquifer thickness and borehole diameter are analyzed based on the calculated values of critical hydraulic gradient and the critical seepage velocity. The present studies indicate that the particle mobilization is directly influenced by the aquifer thickness and the borehole diameter under the same water discharge. It is aimed to provide some theoretical basis to solve the problems of borehole collapse and particle regrouping in the GWSHP’s long-term operation.

Abstract:Based on Computational fluid dynamics, the problem on transient aerodynamic characteristics of sedan and coach crossing each other on road is researched by adopting technology of sliding interface and moving mesh. The car model is MIRA which has been used for many years in foreign country and the coach model was JT6120 which has been tested many times in domestic wind tunnel. The trends and reasons of aerodynamic coefficients changing were obtained from the flow field of simulation results. The quantificational changing of sedan and coach aerodynamic coefficients when they cross each other was obtained. The simulation results indicated that the all aerodynamic coefficients of two vehicles changed large, and the sedan changed much more enormously than the coach. It is different between the trends of sedan and coach aerodynamic coefficients changing. The aerodynamic force was important to the vehicles’ handling stability when they crossing each other.

Abstract:Cu-water nanofluids was utilized as heat transfer medium in the cooling system of the diesel engine, By using CFD-Fluent software, for 0.5%, 1%, 3% and 5% mass concentration of nanofluids, 3-dimensional numerical simulation about flow and heat transfer process in the cooling system of engine was actualized. According to stochastic particle tracking in turbulent flow, for solid-liquid two phase flow discrete phase, the moving track of nanoparticles was traced. By this way, for Cu nanoparticles of different mass concentration nanofliuds in the cooling jacket of diesel engine, the results of the concentration distribution, velocity distribution, internal energy variation, resident time, total heat transfer and variation of total pressure reduction between inlet and outlet were ascertained. It is proved by simulation results that nanofluids as heat transfer medium can evidently enhance diesel engine heat transfer capability, when the concentration of nanoparticles increases, the enhancement of heat transfer capacity increases, power loss of water pump also increases in small scale, the relativity between the average resident time of Cu nanoparticles and Cu nanoparticles concentration is not clear in cooling jacket, the relativity between heat transfer efficiency of Cu nanoparticles and nanofliuds flow velocity is not clear.(以修改稿附件的摘要内容为准）

Abstract:This paper introduces the concept of automated intelligent tire design as basis, and then systemically presents the general framework of CAD 3-D digital tire model design platform, Its modules include the demand representation, demand pre-analysis, product list generation, product list modeling, testing, tires knowledge-base and tire parts-base. The paper also describes the realizing process and key techniques of the product list modeling module, including calculation principle of groove section and groove modeling scheme, and so on. This paper also introduces an improved algorithm of calculating groove centerline; Finally CATIA platform and VBA toolkit-based tire design system has been completed under detailed demand representation type.

Abstract:This paper discussed the method which refines the RFM-based stereo positioning in object space based on known straight line features. For the two refine models (the Shift and main factor model and the Affine model), the formulas were derivated to solve the refine model parameters based on known straight line features. And the solution using known straight line features was given to compensate the RFM positioning error. The experimental results show that it is feasible to refine the RFM-based stereo positioning based on line features; and for the Shift and main factor model, the accuracy of using the straight line features is better than that using points, but for the Affine models, the accuracy of using straight line features is worse than that using points; furthermore, under the same condition, the accuracy of the former is also better than the latter.

Abstract:The relative accuracy of two consecutive points in the network of ballastless track railway must controlled within 1mm, which means that the reasonable and reliable method should be employed to assess the adjustment accuracy. In adjustment problems, improper stochastic model will affect the adjustment result and its accuracy evaluation. In this paper, we will introduce the construction of the first ballastless track railway from Beijing to Tianjin in China. Then, we will use the Helmert variance estimation method to reasonably determine the weights of directions and distances in adjustment processing, thus achieving the reliable the adjusted coordinates and their accuracies.

Abstract:How to get a global minimum of a function over a sphere is studied. Differential equation and canonical dual function are introduced to formulate the perfect duality theory, which shows the relationship between the KKT points of the primal problem and the canonical dual problem. Canonical duality theory and other global optimization methods are applied. Examples are given to illustrate the main idea

Abstract:In this paper, a new QP-free infeasible method with nonmonotone line search techniqueis and the Fischer-Burmeister NCP function is proposed for minimizing a smooth function subject to smooth inequality constraints. This iterative method is based on the solution of nonsmooth equations which are obtained by the multiplier function and the Fischer-Burmeister NCP function for the KKT first-order optimality conditions. We use nonmonotone line search techniqueis on line searches. This method is implementable and globally convergent without assuming the strict complementarity condition, isolatedness of the accumulation point and linear independence of the gradients of active constrained functions at the solution. We also prove that the method has superlinear convergence rate under some mild conditions.