Abstract:As a non-statutory plan, in overall urban design, a holistic vertical and intensity control zoning should be proposed to achieve guidance of the built environment through the statutory planning system in China. However, these traditional technical routes usually give priority to economy with consideration to the artistic value, which cannot be applied to all cities. Therefore, a dual-model of vertical and intensity zoning was proposed in the overall urban design of the city of Dali in Yunnan province. The basic vertical zoning is independently derived from artistic principles while the basic intensity zoning independently originates from economic principles. These two zonings are mutually modified to ensure that the vertical height and intensity of each block are matched with each other, through which the economic and artistic principles are both given consideration to.

Abstract:This paper focuses on the density quantification of the highdensity urban blocks by selecting 30 highdensity urban block samples from the central urban area in Shanghai to study the morphological density and its related parameters and obtain the spatial pattern distribution and spatial morphological types. The conclusion can provide support for morphological quantitative research for planning and urban design practices.

Abstract:Based on the daily monitoring data from 2016 to 2017 and the data of typhoon “Ampil” in July 2018, the dynamic characteristics of Shanghai Tower were analyzed. The fundamental natural frequencies and damping ratios of Shanghai Tower were calculated by using the envelope random reduction method. The variations of dynamic parameters with vibration amplitude at low and high amplitudes were analyzed, respectively. The results show that the fundamental natural frequency of the structure decreases with the increase of vibration amplitude, and the fundamental damping ratio slightly increases with the increase of vibration amplitude. Furthermore, in typhoon “Ampil”, the fundamental natural frequency is still linear with vibration amplitude, and the relationship of the fundamental damping ratio and amplitude is nonlinear because of the influence of the damper. At the design stage, it is reasonable to set the structural damping ratio under normal service conditions and typhoon as 0.3% to 1.0% and 4%, respectively.

Abstract:In this paper, concerning the critical aerodynamic geometrical parameters of a box girder, a series of web inclination angles (33 representative angles) were selected to fundamentally investigate the influence of web inclination angles on stationary aerodynamic stability performance of the long span bridge by using the computational fluid dynamics (CFD) method. The results show that there is a negative pressure zone at the junction of the bottom slab and the incline web when the angle of the web is small, which generates the downward force and decreases the lift coefficient of the box girder. By reducing the web inclination angle, the vertical and torsional displacements of the box girder at each wind speed are effectively reduced. The box girder with a lower web inclination angle can reduce the lift coefficient and drag coefficient of the box girder and can improve the stationary aerodynamic stability performance of the bridge.

Abstract:This paper proposes an improved particle filter (IPF) prediction approach of dynamic reliability indices for bridges based on monitoring time series data. First, the dynamic models, which can provide state equation and monitoring equation for the IPF, are built with the monitoring extreme data of bridges. Next, the Bayesian dynamic linear model (BDLM) is utilized to produce the realtime updated proposal distribution for IPF in order to solve the sample degradation problem and increase the robustness and adaptability of the traditional particle filter. After that, by using the IPF approach, the structural extreme information is dynamically predicted based on the monitoring extreme data, and dynamic reliability indices of bridges are predicted by using the first order second moment (FOSM) reliability method. Finally, three existing bridges and a designed experiment are provided to illustrate the feasibility and application of the proposed model and method.

Abstract:Based on the ultimate equilibrium theory, the size effect, simplified concrete failure criterion, and failure condition of ultra-high performance concrete (UHPC) overlay were considered, and the calculation method of the UHPC-NC ultimate shear resistance was proposed. A shear resistance test was conducted. The on-site measurement and data analysis indicate that this calculation method not only accurately predicts the shear resistance, but also the shows the influence of UHPC overlay, the reinforcement in UHPC overlay, and size effect. The result also shows that the UHPC overlay could improve the ultimate shear resistance and ductility of the overall structure.

Abstract:To simulate the degradation mechanism of concrete piles underground exposed to sulfate attack, the effect of water pressure on sulfate erosion distribution in concrete piles was considered. Based on Darcy law, the relationship between flow velocity and water pressure and time was established. Furthermore, the penetration depth calculation model of water pressure was established. Considering the existing water pressure, a diffusion erosion equation of sulfate in concrete piles was established based on Fick’s second law. Via the method of separation of variables, variable substitution and integral transformation, the analytical solution of the convection erosion equation and diffusion erosion equation without the influence of water pressure were obtained. At the same time, the sensitivity of water pressure to penetration depth was analyzed. The effect of water pressure, water cement ratio, seepage depth, and crack width on the sulfate concentration distribution was analyzed. The results show that with the water pressure increasing the penetration depth increases significantly. Under water pressure, the concentration of sulfate in concrete is significantly higher than that of sulfate when there is no water pressure. The watercement ratio, penetration depth and the crack width have significant effects on the concentration distribution of sulfates in concrete.

Abstract:The concept, intelligence rating, and evaluation of smart airfield in airport are interpreted and proposed in this paper. The vision of smart airfield is clarified as “full-time safety, zero delay, maximal benefit, environment protection”. The definition of smart airfield in airport is proposed based on the elements of smart organism. Smart airfield is defined as an airfield composed of advanced infrastructure, service facility, monitoring network, data center, communication network and energy supply system, which has the ability of self-monitoring, automatic analyzing, self-adaptation, self-operation, information interacting, and continuous energy supplying. Based on the definition, the particular conception and logical relationship of smart abilities are given. Besides, the requirements of intelligence rating and evaluation system of smart airfield are proposed from two dimensions.

Abstract:Aiming at the complexity of the previous pavement condition index(PCI) calculation using triple-level partitioning method of part-area-unit, a novel double-level partitioning method of partarea was proposed along with the analysis of its applicability. Area PCI was first calculated using doublelevel partitioning based on the data from 55 areas in 6 airports. The significance of area location, area size and different airports was then analyzed using single factor variance analysis. The results show that the double-level partitioning method is safety preferable with an average deviation of 1.04 compared with previous triple-level one. The proposed method has little influence on damage level evaluation. Part identification, area size, and airports also have no significant influence on calculation deviation. The double-level partitioning method is recommendable and could significantly reduce workload for pavement condition evaluation.

Abstract:Variable message sign (VMS), as an infrastructure of the urban traffic guidance system, is a main platform to release guidance information. Improper installation of VMS is incapable of information releasing, which has a negative effect on the performance of the urban traffic guidance system and traffic safety. Aiming at VMS design and location problem with urban traffic environment, the process of reading traffic sign was analyzed. With the consideration of VMS reading time and city traffic environment, the VMS installation model was built for calculating the VMS frontal distance and the height of characters in VMS. The amount of information model was constructed for evaluating the complexity of VMS and its reading time. In order to ensure that the driver has enough distance to react after accepting the information from the VMS, the queue length and no change lanes zone were also considered in the VMS installation model. In addition, the evaluation method for existing VMS and the recommended frontal distance and the height of characters were given.

Abstract:A discrete element method(DEM) model of polyurethane ballast bed based on bonding force chain unit was proposed in this paper, based on which, a comparative analysis between common ballast bed and polyurethane ballast bed under cyclic loading was conducted. The results show that polyurethane can lessen the ballasts bed cumulative settlement by reducing the residual deformation and improving the contact status of ballasts. Besides, polyurethane can also increase the dynamic displacement of the sleeper.

Abstract:Based on the study of mechanism of formation of rail corrugation on curved track and investigation of current grinding methods of corrugation, an innovative grinding method was proposed together with a prototype grinding machine with more accurate and efficiency grinding operation. Test grindings on metro line were conducted together with measurements of vibration and noise. The results show that the predicted improvements are obtained with less vibration, lower noise and elimination of screaming noise. The new grinding method is better than the traditional method in convenience and efficiency.

Abstract:Misconnected industrial wastewater entry into rainwater pipe network results in the direct sewage discharge into rivers. Additionally, sudden industrial sewage discharge into sewers without treatment would disturb the normal operation of wastewater treatment plants. To trace the unexpected industrial discharge sources, with food manufacturing as the typical industrial trades, the chemical markers to indicate such kind of contamination were screened. For the selected agricultural and sideline processing or food manufacturing enterprises in China, it was found that potassium, sodium and chloride were ideal markers from the perspective of conservative and significant behavior. Specially, potassium and chloride have a good positive relationship with electric conductivity, providing feasibility for real-time monitoring of industrial wastewater discharge. With these markers, benchmark concentrations to indicate industrial flow of food manufacturing were presented. Accordingly, the method to locate industrial flow source was also proposed based on monitoring at manholes or junctions of urban drainage network.

Abstract:The equation of solute transport in groundwater is divided into the convection equation and the diffusion equation by using the splitting method. The entropy scheme is applied to solve the conservation equation while the central difference scheme is applied to solve the diffusion equation. Numerical experiments show that the scheme does not produce excessive problems, and no physical oscillation occurs.

Abstract:Based on the fused deposition modeling (FDM) technology, the influences of building orientation on surface roughness and supporting area are studied. The surface roughness of parts made by polylactic acid (PLA) at different building orientations is tested in experiments, and combined with the theoretical and empirical formula, a novel model for surface roughness prediction is established which conforms to the actual situation in manufacturing. Through the determination of functional surface, the set of building orientations is established in which the best building orientation can be found aiming at improving the surface quality of a complex multiple-surface part. Based on the stereolithography (STL), a mathematical model for the supporting area is established. The single objective genetic algorithm (GA) is used to optimize the building orientation to minimize the supporting area. Coupling surface roughness and supporting area, a multi-objective optimization based on GA is established to search for the global optimal solution.

Abstract:A parameterized model for local modification structure is built coupled with the finite model to generate a local parametric coupling model. According to the performance, the credibility of the fast coupling parameterization modeling and the accuracy of the local parametric coupling model could be confirmed. Besides, the approximation established by design of experiments and radial basis function can predict the performance of the body successfully and the hybrid method multi-objective optimization can be used to achieve multi-objective optimization design. Therefore, the method built can meet the design effectiveness while saving modeling time and improving optimization efficiency.

Abstract:The aerodynamic noise in the rear view mirror region has an important influence on the vehicle interior noise. Therefore, large eddy simulation and acoustic perturbation equations were used to solve its unsteady flow field and sound field. A comparison of the results between simulation and experiment of the energy averaged total pressure level of the 19 measuring points of the front side window indicates that the difference between them is only 2.3 dB(A). The trend of frequency spectrum is similar and the difference in magnitude is small. Based on this, the active jet model is established and the parameters such as jet position, direction, and speed are changed. Besides, the subdomain simulation method was used to find the optimal jet scheme. Moreover, the optimal jet scheme was put into the vehicle aerodynamic noise simulation model. A comparison with the original model shows that the active jet increases the time-averaged pressure at the wake of the mirror, and reduces the pressure gradient and the vortex intensity of the mirror region. The vehicle aerodynamic drag coefficient is reduced by 0.002 while the energy averaged overall sound power of the front side window is reduced by 1.8 dB(A), and the overall turbulent fluctuation power is reduced by 0.3 dB(A).

Abstract:An automatic lane change (ALC) environment perception system of an electric vehicle is established. Besides, the ALC real vehicle platform and steering system structural transformation scheme are introduced. In addition, a low-cost and reliable environment perception scheme is designed. Moreover, for the front vehicle of the same lane, the data of a 24 Ghz millimeter wave radar and a forwardlooking camera are fused through weighted fusion algorithm. Furthermore, through real vehicle acquisition, the ideal weight curves of the two sensors at different distances are fitted, which improves the accuracy and stability of the environment perception. Finally, the applicability of the ALC environment perception system of the electric vehicle is verified in an obstacle avoidance lane change experiment.

Abstract:To improve the adaptive walking ability of legged robot, a strategy combining the bionic control method and the intelligent optimization algorithm is proposed. The Rulkov neuron model is used to model the central pattern generator (CPG). Based on the CPG model, the single and multi-joint coupling network topology is proposed. The coupling coefficient matrix between CPG units is optimized using the multiobjective genetic algorithm. In this way, the robot’s joints can act correspondingly to timing sequence controlled by the output signals of the CPG network. Finally, the information fusion feedback system and adative walking control strategy are proposed, and a simulation using Webots is implemented on the quadruped robot called GhostDog to experimentally verify it. The experimental results show that the proposed walking control strategy can control the robot to switch walking modes automatically and have certain environmental adaptability.

Abstract:To count the pedestrians in the scenarios with the sparse or dense crowd, a network based on the improved Inception-ResNet-A module is proposed, which is trained with the gradient boosting method of ensemble learning, and the details of the proposed method are given. Besides, a dataset collected in a real scenario, which contains illumination and camera view changes, and other three public datasets are used to evaluate the robustness of the proposed method in terms of illumination, population density, and camera view changes. The experimental results show that the proposed method is robust to the aforementioned changes. In addition, the proposed method favorably outperforms the state-of-the-art approaches in terms of accuracy and stability.