Abstract:There exist randomness both in earthquake actions and in structural performance;therefore,the seismic reliability analysis of structures should be done to assess seismic performance of structures.Two new numerical simulation methods for structural reliability analysis are proposed,which include uniform design response surface method(UDRSM),and hybrid simulation method(HSM) combing Monte Carlo Simulation(MCS) and UDRSM.Theses methods are all implemented in ANSYS by using deterministic finite element method.The new two methods are then applied to seismic reliability analysis of steel frame structures.The accuracy and efficiency of the new methods are demonstrated by contrasting the new methods with the classical numerical simulation methods including Monte Carlo simulation(MCS) and orthogonal design response surface method(ODRSM).The results indicate that difference of UD is 10%-20% of that of OD;The calculation difference of hybrid simulation method based on UD is 42%-85% of the method based on OD;Computing efficiency of hybrid simulation method is more than 480 times of Monte Carlo Simulation.It is found through the numerical example that the experiment points chosen by uniform design are more uniform and representative than the conventional methods,and that the limit state function of UDRSM is more accurate,and the HSM is more efficient.

Abstract:To ensure the anti-collapse capacity of the storey-adding out-jacketing frame cooperated with the existing structure,time-history analysis by IDARC(2D) on the out-jacketing frame under rear earthquake are carried out,which shows that the lateral stiffness of the frame is quite weak below the adding structure;the damages of the existing structure is more serious than the one of the adding structure;and some of the out-jacketing frame designed by Code for design of concrete structures(GB50010—2002) & Code for seismic design of buildings(GB50011—2002) collapse under rear earthquake.Based on the analysis,application limits,column axial compression ratio limits,end-column moment magnification factors and construction measure of the out-jacketing frame are presented.Time-history analysis shows that by these reinforcing measures,collapse of the out-jacketing frame can be prevented effectively.

Abstract:To know the response characteristic of long-span spatial structure subjected to blast loading,finite element software ANSYS/LS-DYNA was used to set up the analytical model of Kiewitt8 single-layer reticulated shell with span of 40 m.The selection and determination of material parameter and constitutive model,element type,mesh dimension and generation and application of symmetric structure for saving computer burden were analyzed.The simulative and experiential values from several references about the peak overpressure of blast wave were compared,and the results verified the creditability and applicability of numerical simulation.Based on the finite element analysis of Kiewitt8 single-layer reticulated shell with varied TNT blast loading and standoff distance,the internal force and deformation for shell members were obtained;The failure characteristics and types of reticulated shell subjected to central explosive blast loading were summarized: no damage,mild impairment,moderate destruction Ⅰ,moderate destruction Ⅱ and severe destruction;And the effects of TNT equivalent weight and standoff distance on the structural dynamical response degree and rule were investigated.

Abstract:Parametric analysis was carried out by ANSYS to investigate the compression performance of a heavy-duty universal hinged cast steel support with the largest bearing capacity.The influences of 6 parameters(34 specimens) on the mechanical and economical performance of the support were analyzed.Analysis shows that the depth of top plate,the height and the thickness of ribs of the bottom support and yield strength of the material have a great effect on the mechanical performance of the support.The height of upper support has the largest influence on the performance price ratio of the support,which can be up to 60%.The depth of top plate of the bottom support,the height and thickness of the ribs of the bottom support have a medium influences on performance price ratio of the support,which are within the limit of 10%-15%.

Abstract:For making up the insufficiency of HAZUS method,that is the determination of damage mean value in the HAZUS method is subjective and fuzzy,the Seismic Damage Index(SDI) in Park-Ang damage model is introduced to describe the structural damage status.Combining the theoretical frame of HAZUS method,a SDI-based prediction method of seismic casualties was proposed,and a six-floor concrete frame structure was analyzed with the proposed method.Results show the feasibility of the proposed method.

Abstract:To study the connection method between reinforced bars of the precast concrete(PC) structure,81 plug-in filling hole for lap-joint of steel bar sample tests were made,and the main factors,such as reinforced bar diameter,concrete strength and anchorage length etc.were considered during the tests.The test results indicated that the ultimate failure state of all the anchoring specimens were the external reinforced bar yielding or broken up by pulling,and the abnormal anchorage was not destroyed.When the basic anchoring length was reduced by 10% or even 20%,specimens still showed enough safety.Based on this,the basic anchoring length of plug-in filling hole for lap-joint of steel bar can be given as 0.8 la.

Abstract:To enrich the nutrients removal pathway and investigate the influence of carbon source on denitrifying phosphorus removal at low temperature(10-12 ℃),a lab-scale A2O reactor was employed to study the process of phosphorus release and denitrifying phosphorus removal with sodium acetate,sodium propionate and their compounds as carbon source.At hydraulic retention time of 8 h,sludge recirculation ratio and inner recirculation ratio of 50% and 150%-250%,the differences of specific phosphorus release rate and the subsequent phosphorus uptake efficiency with different carbon source were obviously.The specific phosphorus release rate and the phosphorus uptake rate was 6.3 and 2.8 mg·h-1 with sodium acetate as substrate.However,the specific phosphorus release rate of sodium propionate and the compounds was 3.44 and 5.56 mg·h-1.The phosphorus uptake rate was 2.05 and 3.81 mg·h-1,respectively.On the other hand,the intracellular polymers synthesized by phosphorus accumulating organisms were varied with different carbon source.The content of PH2MV was improved by the sodium propionate which consequently increased the utilization efficiency of nitrate nitrogen by denitrification PAOs.The compounds of sodium acetate and sodium propionate were considered as the more suitable carbon source for denitrifying phosphorus removal of low temperature wastewater.

Abstract:According to the disadvantages of wastewater two-phase anaerobic treatment process as low start-up speed of ethanol-type fermentation with acidogenic reactor and sludge easily to be washed out,the ethanol-type fermentation formation of acidogenic reactor was studied by seeding anaerobic granular sludge,controlling volume loading rate,loading increased range,alkalinity,etc.The running condition of the reactor was monitored by parameters such as terminal liquid products,pH,ORP and acidifying degree etc.Test showed that the succession process from mixed acid fermentation to butyrate-type fermentation reactor to ethanol-type fermentation of reactor was completed within 34 d.At the end of start-up,the mass concentration of ethanol and acetic acid was 75.9 percent of liquid terminal products;pH value was 4.1-4.3;ORP value was-230——250 mV.The sludge properties of seed anaerobic granular sludge changed obviously.Its apparent color changed from black and grey black to khaki and snuff color.The particle size of seed granular sludge became smaller with the range of 0.50-1.25 mm.

Abstract:To study the long-term effect of dissolved oxygen(DO) on phosphorus removal process,the characteristics of enhanced biological phosphorus removal(EBPR) under the DO level of 5.5-7.0 mg/L and 0.5-1.5 mg/L were investigated systematically using sequencing batch reactor(SBR).The results showed that,when pH was in 7.2-7.6 and temperature was at(23±0.5)℃,high DO had adverse impact on both phosphorus release process and phosphorus uptake process.The amount of released phosphorus in anaerobic period was 43.08% lower than that under low DO condition.Phosphorus uptake process went fast during the initial 30 min in aerobic period.The maximum specific phosphorus uptake rate was 6.27,11.45 mg·g-1·h-1 under high DO and low DO conditions,respectively.Analysis indicated that the main reason of deterioration of phosphorus removal process was deficiency of poly-β-hydroxybutyrate(PHB) caused by excessive aeration and more influent carbon source used for denification process.High DO did not have obvious advantage on restraining filamentous sludge bulking than low DO.The improvement of phosphorus removal was usually associated with the improvement of sludge settleability.

Abstract:To study the effect of aquifer’s hydro geological conditions on standing column well(SCW),the operating characteristics of SCW under different hydro geological parameters were analyzed through large numbers of calculation cases.The results show that the aquifer with larger horizontal permeability coefficient enhances the ratio of original groundwater exchange and lightens the change of pumping temperature.The aquifer stagnant thermal conductivity has little effect on pumping temperature if SCW is in the aquifer with good permeability,however,if with poor permeability,the pumping temperature would be rapidly increased with the increase of the aquifer stagnant thermal conductivity.The permeability coefficient is a key parameter to influence the change extent of pumping temperature obviously.

Abstract:To study the thermal environment of the room which is enveloped by the phase-change concrete composite wall with night mechanical ventilation,the dynamitic heat transfer mathematical physics model of the phase-change concrete composite wall with night mechanical ventilation and thermal balance model of the room are given based on enthalpy method.The dynamic heat transfer performance and indoor thermal environment are simulated in summer and the transitional seasons when the phase-change composite walls are applied in Beijing.The influencing factors of the phase-change composite wall,such as phase-change temperature,phase-change layer thickness,ventilation rate,ventilation time,and the locations of phase-change layer and the insulation layer are analyzed.The optimal results are as follows: phase-change layer should be as the inner layer,phase-change temperature is 26 ℃,phase-change layer thickness is 25 mm,ventilation time is 4:00 am to 6:00 am,and ventilation rate is 25 ach/h.

Abstract:Traveling wave velocity is the key to the measuring accuracy of the time-domain reflectometry cable length measurement system.To reduce the impact of velocity,the velocity characteristics of time domain reflectometry cable length measurement system are studied,the frequency characteristics of traveling wave propagation velocity and dielectric constant are analyzed,and the influence of cable material parameters and ambient temperature on traveling wave propagation velocity on cable is investigated.The basis for determining the wave velocity is summed up.The signal propagation velocity at different temperature is measured,and the temperature compensation coefficient of traveling wave propagation velocity in the PVC insulated cable is presented.Experimental results show that the measuring accuracy of the time-domain reflectometry cable length measurement system is improved significantly by velocity temperature compensation.

Abstract:Uncontrolled intersection vehicle delay is of great significance for evaluating the intersection service level,so that it is necessary to study a relative practical delay calculation method.This paper analyzes vehicles operating characteristic;divides the vehicle delay into waiting delay and acceleration-deceleration delay;uses probability theory to derive an iterative method which includes the average service time and service time variance of every approach;describes the queue phenomenon of uncontrolled intersection with M/G/1 queuing system;proposes the average waiting delay formula;and puts forward the acceleration-deceleration delay of uncontrolled intersection by using the method of signal intersection for reference.It is showed that the theoretically calculated values are close to observed values of delay that come from an uncontrolled intersection of shi-zi street and xuan-wei street in Harbin.

Abstract:To quantitatively study the operating efficiency of right-turning vehicles at signalized intersection,a travel time model was established on the basis of gap theory and queue theory,which was under the assumption that the straight flow of non-motor headway followed the combined negative exponential distribution and right-turning flow headway followed the negative exponential distribution.Comparison was done by field observation data,and the reasons of the results were analyzed and the applicability of the model was set up.Three significant factors can exert apparent effects on travel time,involving right-turning flow rate,following car headway and critical gap.The travel time model of right-turning vehicles at intersection established in this paper is efficient,practical and with strong applicability.

Abstract:A new grouting method and its technology were provided to achieve the goal of pouring the longitudinal crack in-depth.First,the cement mortar mix design which can satisfy the requirement of pouring the longitudinal crack in-depth was investigated,and then,the grouting technology including grouting timing,pretreatment,pore drilling and arrangement,sealing tube embedment,grouting and preserving was determined by sealing the crack in situ on the test road.The result indicates that the cement mortar has good fluidity and early strength,the method can pour the cement mortar into base or even into subgrade to recovery the construction and strength of pavement,which means that the new method can cure the longitudinal crack of asphalt pavement caused by asymmetric sedimentation thoroughly.

Abstract:To identify the number of modes of vibration in the random theory results for wind vibration,the empirical mode decomposition(EMD) method and wavelet transform method are used to analyze the joint characteristic for self-induced response signals of aeroelastic model.First,the intrinsic mode functions(IMF) are directly decomposed from original signal with EMD,and then the signal characteristic parameters of every IMF can be extracted with wavelet transform,which are compared with the results by traditional spectrum analysis method and wavelet transform on original signal.The combination of EMD and wavelet transform method can identify the high-order mode of vibration;the main characteristics of signals in arbitrary frequence band can be obtained;and the distribution of signal energy with time and frequence can be displayed more clearly.The numerical simulation and the analysis of response signal date show that this method is effective and practical.

Abstract:Simultaneous pressure-measured tests on the rigid models for a group of two adjacent large hyperboloidal cooling towers were conducted in TJ-3 wind tunnel of Tongji University.Mean and fluctuating wind pressures were presented for various tower distances and incoming wind angles.Compared with the result of an isolated tower,interference effects produced on each tower by the other one are illustrated by interference factor and quasi-static wind load coefficient.Test results indicate interference effect can’t be neglected even when L/D≥3 and the optimal wind direction is 0°-40° if evaluated by the mean C D.For tandem and staggered configurations,wind pressure distribution and flow state around the cooling towers are also analyzed.

Abstract:The present paper concentrates on overcoming the deficiency of whole bridge aero-elastic wind tunnel test in the acquisition of dynamic stress of bridge elements.Based on both the whole bridge aero-elastic wind tunnel test and finite element method,some research is implemented with the hanger of Jiangdong Bridge as an example.Firstly,verification analysis for displacements is made on results derived from the above two approaches.Thereafter,regression equation is deduced from finite element method under zero yawed angles since the mid-span vertical displacement time history keeps high correlations with the hanger axial forces.Furthermore,displacement time histories of the mid-main span are sampled from wind tunnel test under different yawed angles.Lastly,with the help of regression equation and wind tunnel test results,the hanger’s dynamic stresses are obtained.Research shows that the regression equation in this paper has a significant regress effect in the 95% confidence interval.It is concluded that estimation method in this paper makes up the shortcoming of wind tunnel test for not being able to get structural stresses,and avoids several procedures in finite element method analysis under skew wind excitations,such as the identification of aero-elastic parameters and its complicated framework.

Abstract:Based on the Maxwell visco-elastic constitutive model and the solution of the anisotropic displacement for surrounding rock,the time-varying analytical solution of anisotropic visco-elastic tunnel excavation are presented through the correspondence principle.The anisotropic stress state means that the lateral earth press coefficient does not equal to 1 in this paper.A variety of ingredients on the displacement of surrounding rock are discussed.The results show that when the anisotropic parameter K0>1,the summit of tunnel will move in the direction of surrounding rock and then change to the opposite direction due to the rheological effect.However,the displacement will generate in the direction of inner tunnel when K0≤1,and the time-varying displacement gradually increases with the decreasing of K0.For the midpoint of the tunnel,the influence of the anisotropic parameter is just opposite to the summit displacement of tunnel.Moreover,the time-varying displacement of surrounding rock would increase with the increase of excavation speed and acceleration.The shear modulus and viscosity also have some influences on the time-varying displacement of surrounding rock.

Abstract:Assuming deep buried sand is an aggregate of randomly packed uniform spheres,the equivalent shear modulus and the formula of shear wave velocity(V s) in sand media were derived based on the the spheres-contact theory and the research results of microscopic particles elasticity.Seven influencing factors were analyzed,including porosity,saturation,internal friction angle,soil grain density,magnitude of stress,elastic modulus of sand grain and Poisson ratio of sand grain.The results were compared with the measured data,and the calculated value of V s were generally in good agreement with the measured values.This study indicates that the value of V s is mainly influenced by porosity,magnitude of stress and the elastic modulus of sand grain,and the shear wave velocity increases with the increasing of stress in high stress state,especially after the degree of density achieves 100%.

Abstract:The computational fluid dynamics(CFD) methodology is employed to obtain the wind pressures on the inner surface of large hyperbolic cooling towers.The wind pressures on the inner surface of cooling tower,which are induced by the action of outer wind field and self-circulating system due to air temperature difference,are calculated numerically with the k-ε turbulence model and multiphase model,respectively.The distributions of these two parts of wind pressure with respect to height and latitude are then investigated.The resultant wind pressures on inner surface on cooling tower are obtained and their suggestive values are given.Results from this study show that the wind pressures on inner surface induced by the action of outer wind field vary significantly with heights and latitudes,whereas those induced by self-circulating system keep almost unchanged with respect to latitude.If the velocity of outer wind field is small,the wind pressure on inner surface induced by self-circulating system will occupy a certain proportion of the resultant wind pressures,while if the velocity is large,it can be neglected.

Abstract:Three-dimensional analytical solution of simply supported laminated thick rectangular plates on the Winkler foundation was derived by the finite integral transform method and state space theory.During the analysis process,the preselection of various stress and displacement functions used commonly in thick plate model was abandoned,and based on the basic elasticity equations and variable substitution,a system of partial differential equations with respect to stress and displacement components was reduced to two matrix differential equations,one was second order and another was fourth order.The transfer equation of laminated plates was derived according to the continuity of state space vector of joint surface,the three-dimensional analytical solution of simply supported laminated thick rectangular plates on the Winkler foundation were obtained by the finite integral inverse transform method.Numerical results demonstrate the validity of the method in this paper,and compared with other methods,this method can greatly improve the solution efficiency because of the technique of reduced order.

Abstract:Considering the complexity of surrounding rock classification,some factors such as rock uniaxial compressive strengthen,integrality coefficient of rock mass,the angle between tunnel axis and the main joint,joints condition and seepage measurement of groundwater are selected as evaluation indexes.The evaluation indexes and the standard for surrounding rock classification are used to constitute a set pair.A model of tunnel surrounding rock classification based on set pair analysis is established,which is tested by measured samples of surrounding rock.The model is applied to actual tunnel.The research concludes that the results of SPA are in good agreement with practical situation of surrounding rock.Also,the method of set pair analysis applied to the classification of surrounding rock is feasible and has high accuracy.SPA is simple and has strong maneuverability,which is a good method for surrounding rock classification.

Abstract:To solve current design problems of long-span stay cables,this paper proposed a new design of cable-stayed bridges with carbon fiber reinforced polymer(CFRP) and steel composite stay cables.In this design,the CFRP stay cables with high strength-to-weight ratio are applied in the dead load condition,where the high strength of stay cables is needed;while the steel stay cables with high stiffness and low cost are applied in the live load condition,where the stiffness of entire bridge is concerned.The design strategies and key design parameters for the proposed cable-stayed bridges were determined and the appropriate values of key design parameters were also suggested based on a parametric study.By comparing,it can be concluded that the proposed composite cable-stayed bridges have less cable sag and lower self-weight than cable-stayed bridges with steel stay cables and meanwhile have more stiffness and lower cost than those with CFRP stay cables.It is proved in this study that the use of CFRP and steel composite stay cables in cable-stayed bridges is feasible and the proposed composite cable-stayed bridges could become an excellent alternative to cable-stayed bridges with steel or CFRP stay cables.

Abstract:To quantitatively analyze the level of service(LOS) of taxi boarding areas at airports,passengers’ questionnaires were implemented to evaluate LOS of individual components and overall LOS,which could assess the key influence factors.Each LOS of giving queue time was evaluated based on user perceptions.Regression models were adopt to formulate the evaluation model of overall LOS and the mathematical model between LOS and the queue waiting time,which were used to determine the LOS categories of taxi boarding areas.By analyzing the questionnaires data of Shanghai Hongqiao Airport,it is shown that the four factors: queue waiting time,guiding signs,queue walking distance and organization management,are the obvious influences for LOS of taxi boarding areas,and LOS could be partitioned five categories.The research results could make the administrators know the primary components which should be paid more attentions,and provide the quantitative measurement standards for the planning and design of taxi boarding areas at airports.

Abstract:According to the problem of low performance price ratio of license plate recognition systems which are just for traffic monitoring,traffic flow measurement etc,and the lack of researches on traffic congestion identification methods based on license plate recognition data at present,methods for collecting travel speed of individual vehicle and link average travel speed are designed,and based on these,a method of traffic congestion identification is studied,which is also verified by using measured license plate recognition data on a arterial road of a city in China.The results show that traffic data with high quality can be obtained using the travel speed collection methods,and the duration and types of traffic congestion can be obtained using the traffic congestion identification method,which will provide real-time and reliable decision basis for traffic management departments.

Abstract:To quantitatively study the adsorption,biodegradation and volatilization of diesel polluted vadose zone environment during natural attenuation process,adsorption experiments were conducted to determine the adsorption equilibrium time of fine sand and clay vs saturated solution of diesel,which were 24 h,and the theoretical maximum adsorption capacity of the total petroleum hydrocarbons(TPH) of fine sand and clay were 234 and 430 mg·kg-1 respectively.The comparative experiments including six columns established the biodegradation and volatilization decay kinetic equations of fine sand polluted by diesel,ρ(TPH)=25.48e-0.002 7xand ρ(TPH)=25.48e-0.022 1x,and the equations of clay,ρ(TPH)=25.48e-0.005 1xand ρ(TPH)=25.48e-0.010 9x.The results showed that natural attenuation efficiency of clay polluted by diesel was greater than that of fine sand.

Abstract:In practical,arch bridge,as a major stress plane curving pole system,would be eccentrically pressured by engineering materials,construction process and other reasons.Based on the nonlinear properties,the linear and nonlinear stability analysis,we obtained the various modes of the stability safety coefficient.From the analysis of results,we choose a tension scheme.Taking two nonlinear reasons into account,the stable safety coefficient would be reduced largely,so that the nonlinear effect must be considered in the stability analysis of construction.

Abstract:Polyethylene oxide(PEO)-based solid composite polymer electrolyte(SCPE) may be used as electrolyte material in high energy density all solid lithium batteries.The SCPE films made from PEI-PEO-LiClO4-CA-NCA were prepared using a solution casting method when PEO was used as matrix,LiClO4 as Li+donor,polyethylene imine(PEI),citric acid(CA),inorganic nano-powder(NCA),were used as properties improver.The products were characterized by X-ray diffraction(XRD) and the electrochemical impedance spectra(EIS) of the SCPE had been measured.The results show that the additives decrease the crystallinity of the SCPE films,improve the conductivity of the PEO-based SCPE.The conductivity of the SCPEreached 5×10-4 S·cm-1(25 ℃),while retaining a good mechanical strength and flexibility.