Abstract:To change the situation that the normal constraint-based parametric modeling method is complex, and the modeling efficiency is low, which is difficult for users to master, a parametric steel joint system based on operation was designed. The difference between operation-based parametric modeling and constraint-based parametric modeling in modeling method, system development and the underlying logic was discussed. The principle of operation was introduced. How to write the logical information into the parametric joint was studied and using industry foundation class(IFC) file to save the joint was realized. Operation-based parametric modeling and non-parametric modeling are basically consistent in the modeling method. Compared with constraint-based parametric modeling, operation-based parametric modeling’s efficiency is improved, the parametric information is able to be shared, and the redundant work of developing the similar joints is reduced. At last, the advantages of operation-based parametric system were introduced by examples.

Abstract:For the purpose of investigating the seismic behavior of rocking truss-frame with dampers, finite element models were established by software OpenSees, including frame structure, brace frame structure, rocking-truss-frame structure and rocking-truss-frame structure with displacement dampers. Based on the result of modal analysis, pushover analysis and time-history analysis, the characters of stiffness, dynamic response and damage were discussed. In order to illustrate influence of frame column root connection and dampers, four finite element models were established, which have different types of frame column roots and dampers. According to the analysis, rocking-truss-frame system has great seismic performance. Displacement dampers can improve structures stiffness and capacity, while velocity dampers can decrease story shear force. Pin-supported column roots are helpful to decreasing dynamic response and plastic damage of first floor columns.

Abstract:To investigate the isolation effectiveness of high-performance isolation rubber bearing (HIRB) on the small-to-medium span girder bridges in mountainous areas, shaking table tests were conducted on a two-span continuous girder bridge model in longitudinal direction. The model had different pier stiffness and was isolated by HIRB. Artificial earthquake waves and Northridge waves with multi intensities were applied as input ground motions. By studying HIRB’s deforming performance and measured structural response under various excitations, it is found that HIRB could mitigate the girder acceleration by 58% at most compared with input peak ground acceleration (PGA) and could roll over stably to satisfy the relative displacement between girder and piers under E2 earthquakes of 9-degree intensity with no residual displacement. Test results indicate the feasibility and effectiveness of applying High-Performance Isolation Rubber Bearing in continuous girder bridges with different pier heights.

Abstract:Considering the destructive threat of the maximum individual wave overtopping volume on domestically typical sloped seawalls with crown-walls, in this research, wave flume experiments were conducted to measure the individual wave overtopping volume over the sloped seawall with the crown-wall in breaking wave conditions. Based on the empirical fitting equations for the single sloped seawall without crown-walls, influence factors of crown-walls are introduced to the empirical formula for shape factor and probability of wave overtopping probability for seawalls with crown-walls. It is concluded that the shape factor and the probability of wave overtopping are both related to the relative freeboard and the relative wall height. The shape factor increases exponentially with the increasing of the relative wall height, while the probability of wave overtopping decreases exponentially as the wall height increases. The experimental results can be taken as reference for seawall design.

Abstract:According to the crack depth ,concrete structure is divided into two parts，cracks zone and sound zone. Based on Fick’s second law, diffusion equation of chloride ions in cracked concrete structure is established. Combined with the initial and boundary conditions, analytical solution of the diffusion equation of chloride ions in cracked concrete structure was derived by the Laplace transform method. Finally, the influence of crack width and depth on the distribution of chloride ions and the durability life of reinforced concrete structures was analyzed. The results show that the smaller the depth and the larger the width of the crack, the greater the difference between the chloride ion concentration in the case of crack nonpenetrating crack and the chloride ion concentration in the case of penetrating crack. With the increase of the ratio of crack depth to cover depth, the service life of reinforced concrete structure decreases first and then increases. When dcr/dc=1.0, the service life approaches to the minimum. When dcr/dc>1.6, the service life can be approximately calculated according to the condition of penetrating crack.

Abstract:Non-uniform frost heave of rock in cold zone tunnel under unidirectional freezing condition is one of the main reasons for tunnel frost heave force. To study the frost heave characteristics of fractured rock mass in cold regions, laboratory tests of frost deformation in fractured saturated sandstone and tuff under unidirectional freezing condition have been conducted. The freezing process and frost deformation of the fractured rock mass under the unidirectional freezing condition have been analyzed. A significant difference exists between the frost heave at the fracture and the rock itself. The fractured rock mass shows evident non-uniform frost heaving characteristics during the frost heaving process. For saturated sandstone with deep fracture, the normal linear frost heave rate increases with the increase of fracture width. For fractured saturated sandstone, the linear frost heave rate of rock increases and the normal linear frost heave rate of fracture decreases obviously with the decrease of the freezing temperature. The frost deformation of the fractured tuff is mainly contributed by the frost deformation of the fracture, and the rock itself contracts during the freezing process. According to the experiments, the non-uniform frost heaving coefficient of saturated sandstone with fissures is calculated considering the influence of fracture. When the fracture is parallel to the direction of temperature gradient, the non-uniform frost heaving coefficient of saturated sandstone with fracture decreases with the increase of fracture width. The non-uniform frost heaving coefficient of saturated sandstone increases with the increase of temperature gradient. The increment of non-uniform frost heaving coefficient of saturated sandstone with fractures is larger than that of saturated sandstone. The test preliminarily reflects the non-uniform frost heaving characteristics of fractured rock mass, and provides experimental basis for the calculation of frost heave deformation of fractured rock mass in cold region tunnels.

Abstract:Crack detection and measurement are accomplished by manual detection with crack scales, which is time-consuming and money-consuming. The research was proposed to detect and measure the cracks on the surface of concrete structure, based on computer vision technology. The measurement device was consumer-grade camera, which was relatively inexpensive. Crack detection involves image blurring, image enhancement, morphological operation, image distortion calibration, connected-domain labelling, isolated point elimination, and crack segmentation matching. Furthermore, the research calculated the length and width, as well as records and development direction of extracted crack pixels. Moreover, in the monotonic loading test of reinforced concrete beams, after taking photos of cracks on the beams and compared with the results by traditional methods, the proposed method attained the decent precision of the computer-vision based crack detection and measurement.

Abstract:An accident rate-based lifecycle operational reliability analysis approach of urban water distribution networks was proposed using the accident rate models for different pipe materials, the simulation models for different accidents, and the Langelier-based pipeline roughness model. The values of some key parameters were suggested by sensitivity analysis. Then, the operational reliability analysis of a case network was performed, by which the weak areas were determined and the network improvement measures were introduced.

Abstract:Two elements of urban expressway construction timing, which were the timing of startup of expressway and the construction sequence of expressway network were put forward. The dilemma that current urban expressway construction was lack of scientific decision-making basis was pointed out. The experience of urban expressway construction arrangement in typical domestic cities were summarized. Then, the factors affecting the timing of expressway construction startup were analyzed, and a factor model which based on gross domestic product, population scale, urban area, vehicle ownership et al was proposed with corresponding decision criteria. Then, the influencing factors of the construction sequence of the expressway network were also analyzed. Following the quantitation of influencing factors, an urgency model which based on land development (renewal) index, expressway functional impact index, traffic demand index, implementation condition index and construction capital index was proposed with corresponding decision criteria. In the end of the paper, Jiaxing expressway network was taken as an example to explain the models and corresponding decision criteria.

Abstract:In order to improve the decision level of pavement routine maintenance expenditure of expressway, hierarchical regression analysis method was used to quantify the influencing factors of routine maintenance cost. The influencing factors were defined as regional factors, ages, extra-large bridges ratio, long and extra-long tunnel ratio, and traffic factors which were divided into five cases. The quantitative research was carried out based on the historic data of 16 highway pavement assets after the variables were pretreated. The results show that the overall explanatory power of each group to the model is remarkable under the condition of controlling regional variables; the incremental explanatory power and the statistical significance in each group of the age are the most remarkable; the normalized regression coefficient (beta coefficient) of the extra bridge ratio is larger than the long and extra-long tunnel ratio under the same conditions ; and the beta coefficient of the AADT (annual average daily traffic) and heavy traffic flow are greater than other traffic groups. Thus, the calculation of pavement assets routine maintenance cost is affected by regional factors, the age, the extra bridges ratio, AADT and heavy traffic flow.

Abstract:In order to save construction costs on the premise of the needs of high-speed maglev trains for safe and continuous operation. A setting method of auxiliary stopping area for high-speed maglev based on protection speed curve is proposed. Based on this, an auxiliary stopping area method based on the benchmark running speed curve is presented, which can meet the requirements of safe and continuous operation of the train where multiple target speed curve coexist on the line. The corresponding auxiliary stopping area adjustment method, which has considered the safety requirements of the train operation control system, in engineering application is given, and the simulation calculation is carried out under certain working conditions, the results show that the auxiliary stopping area method can reduce the construction cost of high-speed maglev transportation system to a certain extent.

Abstract:Based on mass induction method, state space theory and modal space theory, three methods were proposed for identifying physical parameters of the mass above the suspension of the bogie system. Designed directional excitation test conditions for physical parameter identification. The above physical parameter identification methods were verified and compared by simulation test. The results show that when using mass induction method, state space theory, and modal space theory, the additional mass size is selected as 8%, 17% and 7% of the system quality respectively, the higher recognition accuracy can be achieved. In general, the modal space theory has the highest recognition accuracy, the state space theory is second, and the mass induction method is the worst. For the identification of quality parameters, inertia parameters, vertical stiffness and damping parameters, the influence of the height between the centroid of the mass above the suspension of the bogie system and the position of the lower point of the suspension can be ignored. When the height is small, the influence of the structural parameter identification error can be ignored.

Abstract:Based on the field observations and related dynamic simulation results, this paper analyzes the gauge corner contact problem on tangent of conventional railway lines. A solution based on the individualized rail profile grinding technology was proposed in this paper and its effect in actually application is observed. The results demonstrate that lateral displacement and force state caused by asymmetric wear of the left and right wheels and the insufficient selfaligning ability caused by the lower gauge corner side of rail profile are the two main reasons for the gauge corner contact. Due to the fact that the wheel condition of freight car is not ideal, rail profile grinding can reduce the gauge corner contact probability, but it is difficult to eliminate the phenomenon only by improving the rail profile. Taken the prediction of contact position distribution between the rail profile and the measured wheel profiles as one of the checking conditions for the design result of rail grinding target profile can effectively optimize the wheel-rail contact position and then can alleviate the gauge corner contact problem.

Abstract:The typical passing frequency of the corrugation was obtained by analysing the measured data of the rail corrugation of the common fastener track section on a metro line. Then, the three-dimensional solid finite element model was established and the modal analysis was carried out. It was found that the typical passing frequencies of the measured corrugation are close to the frequencies of some bending modes of the track structure. Finally, based on the theory of friction work, the wear calculation model was established and the simulation was carried out. The frequency characteristics and development process of the corrugation were analysed and studied. The results showed that the peak value of the common fastener track at the low frequencies is relatively high, and the peak frequency is basically the same at different vehicle speeds. Combining the wear superposed graph and one-third octave diagram, it can be concluded that at the same speed, with the increase of the superposition number, the superposition position of the peak and valley of the corrugation is the same respectively, and the characteristic frequency is the same; and at different speeds, the characteristic frequencies of the corrugation do not change with the change of the speed, which reflects the characteristics of the fixed position and frequency of the corrugation. At the speed of 80 km?h-1 and 60 km?h-1, the corrugation is more likely to occur in the frequency band of 40 Hz and 80 Hz, while at the speed of 40 km?h-1, there is mainly uniformity wear on the rails. At the same time, the speed of the vehicle has a certain influence on the growth of the corrugation. The higher the speed, the greater the overall wear loss, but the development speed of the wear does not completely increase with the increase of the vehicle speed.

Abstract:In view of existing serious failures and short service life of rails in the switch area of railway turnouts, based on the wheel-rail contact theory, the method employs the rolling radius difference function and the uniform distribution of the wheel-rail contact points for the primary design objectives. Using the position of the wheel-rail contact points as a boundary condition, the Euler method was adopted to solve the differential equation and obtained the target profile of rail grinding. A computer program based on this method was developed and is validated by way of examples. After the optimization, rail and wheel profiles are better matched, which improves the dynamic performance of rail vehicles crossing turnouts and reduces the wheel-rail contact stress. As a result, the distributions of contact points and wear are more uniform, leading to a prolonged rail service life.

Abstract:The definition of approximately 2-local derivation on von Neumann algebras is introduced based on the definitions of approximately local derivation and 2-local derivation. Approximately 2-local derivations on semi-finite von Neumann algebras are studied. Let M be a von Neumann algebra and Δ: M→M be an approximately 2-local derivation. It is easy to obtain that Δ is homogeneous and Δ satisfies Δ(x2) =Δ(x)x+xΔ(x) for any x∈M. Besides, if M is a von Neumann algebra with a faithful normal semi-finite trace τ, then a sufficient condition for Δ to be additive is given, that is, Δ(Mτ)⊆Mτ, where Mτ={x∈M:τ(|x|)<∞}. In all, if Δ is an approximately 2-local derivation on a semi-finite von Neumann algebra with a faithful normal semi-finite trace τ and satisfies Δ(Mτ) ⊆Mτ, where Mτ={x∈M:τ(|x|)<∞}, by the conclusion that the Jordon derivation from a 2-torsion free semi-prime ring to itself is a derivation, it follows that Δ is a derivation.

Abstract:For graphs G and H, Ramsey number r(G,H) is the smallest integer r such that every red/blue edge coloring of Kr contains either a red copy of G, or a blue copy of H. Complete critical Ramsey number rK(G,H) is the largest integer n such that every 2-coloring of Kr－Kn contains either a red copy of G, or a blue copy of H. When positive integer n≥5, rK(Cn,K4)=n/2, Cn is cycle with n vertices.

Abstract:Aiming at the fuzzy and uncertain information of language evaluation in traditional quality function deployment （QFD） on the construction process of quality house, an improved QFD model combining hesitant fuzzy 2-tuple linguistic variables, multiple criteria decision making methods such as AHP and TOPSIS is proposed, to determine the importance ranking of quality characteristics. The proposed model consists of three stages. Firstly, the relationship between user needs and quality characteristics is evaluated. Secondly, the relative importance weight of user needs (Cs) is determined. Lastly, the importance ranking of quality characteristics (Qs) is determined. Through the above steps, the accuracy of importance ranking of quality characteristics is improved. Finally, an example of importance ranking of quality characteristics of the digital language learning system from one enterprise was given to demonstrate the effectiveness of the proposed approach. This research may provide a reference for improving the design quality of E-learning system that user-centered.

Abstract:Improving the competitiveness of public transport is critical to the sustainable development of public transport. Analyzing the competitiveness of public transport from the perspective of behavior can meet the needs of travelers better and achieve the goal more effectively. The bus rapid transit (BRT) competitiveness model was established and the structural equation model method was used to do analysis. Based on the data surveyed at the scene of the Urumqi, the competitiveness model was estimated. The results show that the passenger satisfaction is the key factor in promoting the competitiveness of BRT, and it is also the intermediary variable of service quality influencing BRT competitiveness, therefore only that service improvements specific for passenger demand are effective. Based on model results, some corresponding suggestions were provided for BRT service improvement.

Abstract:With the acceleration of population aging in China, the variable annuities have drawn a lot of attentions due to its anti-inflation, pension and investment functions. This paper studies the valuation of variable annuities embedding various guaranteed minimum benefits. We propose a willow tree method for pricing variable annuities under the jump-diffusion model in three guarantee types, including return of premium, Roll-up and Ratchet types. Our tree structure can be easily extended to other stochastic models. The willow tree construction and pricing procedure are independent of each other. Thus, for different stochastic models, it does not need extra work and has better applicability. Finally, numerical experiments demonstrate the accuracy and high efficiency of the proposed method compared with Monte Carlo method.