Abstract:Based on the damage spread process of reinforced concrete beam column member, the damage spread model adjusts the length of damage zone in every loading step. The modified Gauss Radau integration scheme is employed to assure one integration point in the field of the damage, the plastic zone length issue of the segmented fiber beam column raised by Scott & Fenves is avoided. In the end, the comparison between the theoretical and experimental results of a reinforced concrete column verifies that with the model, rational results can be obtained, and the damage spread of reinforced concrete beam column member can be simulated.

Abstract:The paper presents an analysis of the cause to the capillary pressure. Then, the paper explores the relationship between the capillary pressure and the curved liquid water surface in pores and the relationship between the capillary pressure and relative humidity, respectively. Hysteresis effect occurs in desorption process in comparison with that absorption process, and the reason is illustrated by using cylindrical holes. A prediction model for the relationship between capillary pressure and saturation in desorption process is therefore set up on the basis of the hysteresis effect. Finally, an analysis is made of the influence of temperature on relationship between capillary pressure and saturation with a consideration of the adsorption isosteric heat effect. Analysis results show that with the rising of the temperature, the capillary pressure gradually reduces at the same saturation.

Abstract:A new self locking anchor (SLA) is proposed in order to apply the lateral pre stress to the concrete columns. By using this device, the lateral fiber reinforced polymer (FRP) sheets can be post tensioned effectively so that the core concrete can be actively confined. Then the strength and ductility of concrete columns can be highly enhanced and strengthened with lateral pre stressed FRP sheets, and the strength of FRP can be fully used. According to the construction process of SLA, the major reason for the lateral pre stress loss is analyzed. Based on the experimental research and theory analysis, including the friction loss，carbon fiber reinforced polymer(CFRP) relaxation loss，concrete creep loss and other factors, various discipline and related relationship are found. Finally, proposals to reduce the lateral pre stress loss are put forward.

Abstract:A frame structure model which was made of recycled aggregate concrete (RAC) with 100% replacement of recycled coarse aggregates was tested on the MTS shaking table. The natural frequency, equivalent stiffness, the damping ratio, the vibration mode, the acceleration response and the displacement response and so on were analyzed and discussed. The result indicates that the damage of the RAC frame model develops progressively; the natural frequency descends; the lateral stiffness degrades; the damping ratio ascends and the acceleration amplifying factor decreases gradually with the increasing earthquake intensity. The inter storey drift was adopted as the index to evaluate the seismic performance of the RAC frame model structure. Although the model was subjected to very severe damage after several earthquakes, it did not collapse after 1.170 g test phase. The results show that the RAC frame buildings have good seismic resistance capacity.

Abstract:Based on finite element method, a series of two dimensional plane strain models of typical framework and underground station were built to study the influence of superstructure on infrastructure’s dynamic response with various ground motion inputs, spacing between constructions, stiffness and damping of subsoil, foundation buried depth and floor and stiffness of superstructure. Results show that earthquake wave exerts a tremendous influence. Interaction diminishes rapidly with the increasing of the structure gap when the damping of subsoil decreases and the foundation buried depth and floors’ number of superstructure increases, interaction gradually augments. The effect of superstructure’s stiffness on interaction is negligible.

Abstract:Based on the static tensing test, the dynamic mechanical behavior of new grade 3 steel bars (NG3S) with different strain rates was first experimented systematically on the rapid loading test machine of KG 5, the complete dynamic stress time curves of NG3S under high strain rate were given, and the dynamic mechanical properties of NG3S were analyzed based on the test results. Then, through dynamic beam test on the rapid loading test machine of KG 500, the static and dynamic bending bearing capacity of NG3S concrete beams with different reinforcing percents and concrete strengths were studied by experimental method and compared with the beams with ordinary grade 2 steel bars. The result shows that the NG3S materials are of good dynamic properties and its dynamic performance increases with the strain rate, but the plastic property maintains invariable. The adoption of NG3S in protective structure brings a favourable comprehensive benefit. Finally, the key problem was put forward that the NG3S should match with the concrete strength.

Abstract:Based on principles of energy conservation and energy minimum ratio proposed by Rowe, the dilatancy equation considering particle breakage was established on micro level. In order to verify the correctness of dilatancy equation, the corresponding elastic plastic constitutive model was set up by introducing the modified hardening rule. Then the numerical simulation of triaxial tests about two different shape coarse granular aggregates was carried out. Results show that this model can accurately describe the dilatancy characteristic and stress strain relationship of coarse granular aggregates.

Abstract:On the assumption that the back filled grouts should be viscosity degeneration fluids, and the grouts diffuse with half spherical surface, the grouts diffusion area and the pressure to shield tunnel segments were derived with Darcy’s law. As a result, the formula to calculate the radius and the pressure were acquired. The diffusion radius and the pressures to shield tunnel segments with different grouting pressures, grouting time, grouts initial viscosities, and soil permeability coefficients were compared between the grouts viscosity degeneration condition being taken into consideration or not. The diffusion model of grouts pressure is also acquired. The result shows that the grouts viscosity degeneration has a significant influence on the diffusion radius and the pressure to shield tunnel segments on the condition of high grouting pressure, long grouting time, and big soil permeability coefficient. The grouting effect can be improved by adjusting grouting pressure, grouting time and grouts properties.

Abstract:In order to evaluate the water retention capacity of loess and filling about ground fissure and investigate the soil water retention curves (SWRCs) from the micro point of view, the SWRCs of the two soils were measured, and the SWRCs and the air entry values of two soils were calculated based on micro structure. In addition, the characteristic of SWRCs were analyzed from pore size distribution (PSD). The research results indicate that the SWRC of loess lies above that of the filling at low suction range and almost coincides with it at high suction range, and both curves show hysteresis phenomena. The calculated SWRCs based on PSD are similar to the measured in shape and also show hysteresis characteristic. For each soil, the air entry value of the measured SWRC and that calculated by Schubert’s theory are respectively close to the lower limit and the upper limit of calculated value by the proposed formula based on particle arrangement while the air entry value of the calculated SWRC lie between the lower limit and the upper limit. The main reason for the difference of SWRCs between the loess and the filling is that the loess has more macro pores and similar distribution of small pores compared with the filling. The middle flat section in SWRC is founded to be caused by the dual porosity structure.

Abstract:In order to prevent freezing damage to tunnels in cold regions, tunnel heating system with geothermal resource heat pump was introduced for the first time at Linchang tunnel in Inner Mongolia Autonomous Region of China. Finite element method （FEM）was employed to analyze the process of heat exchange. First, the thermal properties of rock mass was inverted by calculating initial temperature field. Then, a heat flow function was obtained which is fitted with the heat flow calculated by the experiment data, and a transient heating analysis was made. A comparison between the numerical and experiment temperature proves that the accuracy requirement can be met. Finally, the distance between pipes was optimized by this method, and the most economic distance between pipes ranges from 0.5 to 0.8 m.

Abstract:Traffic incident duration is one of the most important indexes in accident management studies. The semi parametric proportional hazards model (Cox model) and parametric accelerated failure time model (AFT model) were employed for analysis of the association between multivariate incident durations and risk factors. With the three year traffic incidents data collected from some freeways in Zhejiang Province, the Cox model and AFT model with covariates selected to remain in the model and survival probability of sensitivity to common covariates were illustrated and compared. Based on the Cox and the Log logistic AFT models, the parameter estimates showed that six significant covariates were selected to remain in the estimated survival functions, including accident time, accident type, number of lanes occupied, number of the injured and accident of fatality. With regard to the most significant indicator variable (accident of fatality), the estimates of the survival probability curves for duration demonstrate that the AFT model give a higher sensitivity than the Cox model, and the Cox model is more appropriate for short time incident duration prediction. Moreover, survival analysis models can predict duration based on incident report and benefit rescue countermeasure and emergency aid decision after accidents.

Abstract:Generalized estimating equation (GEE) was applied to account for the correlation among intersections from corridors. Risk factors including intersection location, geometric design, signal control, and operation condition were identified. The results show that GEE with the autoregressive correlation structure is the most effective way to deal with the spatially correlated data. It confirms that intersections in close proximity, with greater ratio of turning lanes, more number of phrases, and more ADT tend to have higher crash frequencies; 4 legged intersections and intersections under elevated expressways are associated with more crashes.

Abstract:A vehicle acoustic signal is composed of engine noise, tire noise, air turbulence noise and exhaust noise. Traffic noise signals mixture of multiple vehicles’ acoustic signals is determined by the traffic state. Based on the analysis of the existing traffic state identification methods and vehicle sound characteristics, an identification method of the traffic flow state was proposed by using traffic noise signals. In accordance with the vehicle speed, traffic flow states were divided into the free flow, saturation flow and traffic jams. The spectrums of vehicle acoustic signals were analyzed for different traffic states, the normalized peak frequencies were as features, and different traffic flow states were recognized using support vector machine. The test results show that different traffic flow states can be correctly recognized with traffic noise signals with a high recognition accuracy.

Abstract:This paper focuses on travelers’ choice behavior of park and ride or driving alone in commuting trips. Revealed preference(RP) and stated preference(SP) surveys of car drivers’ and public passengers’ mode choice behaviors are performed in typical park of ride (PR) transfer station in Shanghai. Based on survey data, influencing factors of PR choice are analyzed. Two individual binary logit models are established under smooth traffic state and congested state respectively on whether car drivers will park and transfer to metro. Model results show that young commuters with lower income are more likely to choose PR. Whether a household has elders or children influences PR choice significantly under congested traffic. The results also indicate that commuters put more attention on travel cost when traffic is fluent. However, they care more about time consumption and comfortableness when traffic is congested. Furthermore, the influence of time and cost sensitivity on PR choice behavior is presented.

Abstract:This research paper is directed toward obtaining a better understanding of in vehicle congestion influence on choice of public transit mode. Considering the complexity of survey respondents, a revealed preference survey and stated preference survey combined survey method is provided. According to orthogonal test principle, composite design is carried out for variables and levels in SP survey. Based on a large scale survey for tourists in all urban rail transit lines of Shanghai, this paper advances the method to describe and classify congestion degree according to density of standing passengers, so as to establish the discrete choice model including time, cost and congestion, and analyze congestion influence on travellers’ desire for choice of traffic mode through elasticity analysis of congestion. The model calibration result shows that travellers are more sensitive to in vehicle time, and change of congestion will obviously influence travellers’ choice of travel mode. The analysis of elasticity show that travellers choosing conventional public transit are very sensitive to congestion degree, and after congestion decreases, travellers’ sensitivity to travel time and travel cost also decreases; and change of rapid transit service level will influence more on demand for conventional public transit.

Abstract:Based on ABAQUS software, a 3 D finite element model containing the contact problems of rivers or creeks and soil as well as pipe soil was established to analyze the mechanics on mechanism responses of buried piles. Behavior of the pipe vertical soil pressure,lateral earth pressure and pipe stress were evaluated in detail with respect to varied foundation treatment. And the behavior of the top soils difference settlement was evaluated by layer wise summation and finite element method(FEM). The results indicate that the max soil pressure on pipe top, bottom and side of pipe occurs when vehicle load is on the top. The Mises stress, which can reach up to 4.887 MPa, can’t be neglected. Layer wise summation can’t be calculated precisely for the soil pressure concentration phenomenon caused by pipeclay relative stiffness is not taken into consideration. And the problem can be solved by a combination of FEM with layer wise summation method.

Abstract:The fractions variation and the removal efficiency of dissolved organic matter (DOM) by polyaluminum ferric chloride sulfate (PAFCS) in coagulation flocculation process were investigated by taking a storm sewer system in Shanghai for example. The results show that in overflow wastewater, hydrophobic matter (HoM) and hydrophilic matter (HiM) account for 68% and 32% respectively; and molecular weight (MW) more than 300 kDa and 10～50 kDa fractions account for 29.76% and 37.87% respectively. PAFCS is effective on DOM removal and total organic carbon (TOC) removal efficiency is 17% approximately, and the removal efficiency of HoM fraction is higher than HiM fraction. The removal efficiency of MW more than 300 kDa and 100～300 kDa is between 20% and 25% approximately, but the MW less than 10 kDa and 50～100 kDa fractions are rarely removed in coagulation flocculation process.

Abstract:A method based on the coupling of microwave digestion and inductively coupled plasma optical emission spectroscopy determination was developed for heavy metals in printed circuit board (PCB). Detailed optimizations of sample preparation, digestion temperature setup and digestion regents usage were enabled to obtain the maximum extraction efficiency of metals from PCB samples. The recommended multi reagent microwave digestion technology, in which the volumes of HNO3 H2O2 HF were 7 ml, 2 ml and 4 ml respectively, could decompose PCB matrix efficiently and dissolve heavy metals into solvent very well. By using the optimized method, the analysis results of practical PCB samples were accurate and reproducible. And the results show that the contents of heavy metals in different PCB samples are quite discrepant and the amounts of Cu and Pb are even up to 27.1~441 g·kg-1 and 0.2~29 g·kg-1.

Abstract:Nine surface sediments were collected from urban rivers of Chaohu City, China, for an analysis of 7 heavy metals (Hg, Cu, Pb, Zn, Cr, Ni and As). A comprehensive way was conducted to investigate distribution patterns and assess the potential ecological risks of heavy metals. The results indicate that the sediments are severely contaminated by heavy metals and mean concentrations of Hg and As are above PEL values. The contamination order of the 7 metals is Ni, Hg, Cu, As, Cr, Zn, Pb according to the mean Igeo values, while the single potential ecological risk of heavy metals followes the order Hg, As, Cu, Pb, Cr, Ni, Zn. The element Ni was the main pollutant and Hg was the second most abundant element with the most serious ecological risks. More attention was demanded to the metalloid As in ecological risk assessments. The pollution of the remaining 4 metals was slight with little ecological risk. The distribution pattern of Hg individual potential ecological risk indices was similar to that of the general potential ecological risk indices for all metals. More concern should be focused to West Huancheng River suffering serious ecological risk.

Abstract:An analysis was made of the physicochemical characteristics of fly ashes from seven municipal solid waste incinerators (MSWIs) in China. Based on the analysis of these characteristics, the relationship between the components of raw refuse and total/soluble chlorine content, heavy metals distribution of fly ashes was discussed. The results show that heavy metal contents of fly ashes have close correlation with the components of raw refuse and refuse collection mode. Fly ashes have a high chlorine level (5.21%~14.49%) and soluble chlorine contributed 40.60%~83.96% to the total chlorine. Chlorine shows wide range content in different incineration plant, the fly ash of incineration plant from city on a comparatively developed economic level tends to have higher level of chlorine. The chlorine (especially soluble chlorine) in fly ash is mainly from kitchen wastes.

Abstract:The hydraulic path and the dissipated power path were presented, and the related minimum paths configuration of water distribution systems (WDS) were obtained by using the Dijkstra shortest path algorithm and visualized in GIS. The district metered areas (DMAs) were set up by mean of flow meters and valves considering pressure distribution, districts and roads. It is suggested that the flow meters should be installed in the minimum hydraulic paths and the valves should be installed in the minimum dissipated power paths to reduce the impact on the reliability due to pipes closed. The impacts of DMAs on WDS are evaluated by three types of performance indices including energy indices, statistical pressure indices and hydraulic indices. The DMAs structure of WDS is achieved and, the flows in different DMAs are shown.

Abstract:The naturally curved and twisted beam theory was applied to the beams for anisotropic materials, and an analytical expression for the warping function of Saint Venant’s torsion of unidirectional composite bars with rectangular cross section was obtained. Then, the differential equations of motion for unidirectional composite cylindrical helical springs with noncircular cross sections, which consist of 14 first order partial differential equations, were further derived. In the formulation, the warping effect upon natural frequencies and vibration mode shapes was first studied in addition to considering the rotary inertia, the shear and axial deformation effects. Improved Riccati transfer matrix method was introduced to solve the free vibration differential equations of the springs which presented a strong rigidity. Calculation results show that, for unidirectional composite cylindrical helical springs with rectangular cross section, the warping deformation has a significant influence on the free vibration characteristics of such springs, which should be considered in the free vibration analysis. Finally, the effects of various parameters on the natural frequencies of the springs were investigated.

Abstract:Insolating not hot coating is made out by using a cheap alkaline earth carbonates material with low solar absorptance and high emittance as filler of coating. The results of experiments in Hainan province indicate that the indoor temperature of the experimental house painted with the insolating not hot coating on the color steel corrugated sheet roof is 2 ℃ lower than that painted with a heat reflecting coating from market on the same roof, and 10 ℃ lower than that painted with nothing on the same roof. When air conditioning temperatures of three experimental houses are all set to 24 ℃, the 24 h electricity consumption of the house painted with the insolating not hot coating is 1.72 kWh lower than that painted with nothing, and 0.81 kWh lower than that painted with the heat reflecting coating from market. When air conditioning temperatures of experimental houses are all set to not less than 26 ℃, the electricity saving rates of the house painted with the insolating not hot coating are 40% higher than that painted with nothing, and higher than that painted with the heat reflectting coating from marke by 15.6~20.8 percents.

Abstract:A finite element model of a bus is established, and according to the ECE R66 regulation, multi objective optimization is carried out for the bus rollover safety. First, on the basis of the rollover simulation result, the section shapes of the key parts in the upper structure are selected as design variables. The maximum acceleration of the center of gravity and the mass are then taken as objectives, and the angles between side pillars and the floor are selected as constraints. Then, combined with optimal Latin Hypercube， the Kriging models of high accuracy are constructed. Finally, multi objective optimization for the bus rollover safety is performed with NSGA II, and the Pareto optimal set is obtained. The conclusion is drawn that the rollover safety can be improved by using section shape optimization when a limited mass is increased.

Abstract:Wire rope nondestructive testing excitation structure model is established according to the characters of wire rope defect. The value of magnetization intensity was determined by the influence of magnetization intensity to localized fault (LF) and loss of metallic cross sectional area (LMA) defection signals. Meanwhile, whether the rope can be magnetized to a certain degree was regarded as a standard for a rational design judgement. Based on the equivalent circuit model of excitation structure, parameters of excitation structure size were obtained, and then an analysis was made of the impacts of the excitation structure size variation to excitation, as a result, the size of the excitation structure was obtained. A simulation of the excitation structure of finite element by ANSYS shows that there is a gap between the theoretical calculation dimension and the magnetized intensity, an ideal value of intensity can be achieved by adjusting the key dimension values, and the last dimension values provide a reference for the excitation structure dimension design.

Abstract:The abnormal fluctuation of RMB non deliverable forward rate (NDF) was identified with Markov regime switching approach by taking the non linear characteristic of exchange rate volatility into consideration. Empirical analysis showed that around July 21th 2005 and June 19th 2010 when the central bank reformed the exchange regime, NDF exchange rate abnormally fluctuated , and immediately after the reform the appreciation expectation pressure was intensively released, which suggested that RMB exchange rate reform stabilized appreciation expectation. During the international financial crisis from the second half of 2007 to the beginning of 2009, NDF exchange rate continuously fluctuated abnormally, and the long term NDF volatility was obviously affected by “U shape” trend of USD, which indicated that the expectation of speculators was more sensitive to the impact of international financial markets. The study results define the period during which RMB appreciation pressures are accumulated and the different expectation characteristics of different market players. The stuty is of a good reference value for China’s central bank to stabilize RMB exchange rate.

Abstract:A new synthesis method of analytic hierarchy process (AHP), principal component analysis (PCA) and data envelopment analysis (DEA) was proposed to solve the vendor selection problem. And a case study was made on the method. The study result was compared with those by synthesis method of AHP and DEA. The result shows that the synthesis method can effectively eliminate the data redundancy and it can avoid overlapping evaluation caused by principle co relationship.