Abstract:The modified form of the Park-Ang damage model for reinforced concrete (RC) structures is put forward with a consideration of the non-convergence of the original model on the upper and lower limit.Then the combination coefficient is calculated on the basis of the cyclic test results of RC columns from the database of the Pacific Earthquake Engineering Research Center (PEER) and the authors’ tests.An empirical formula is derived through nonlinear regression analysis to relate the coefficient with the axial load ratio,shear-span ratio and confinement index provided by the transverse steel.The comparison between the two models indicates that compared with the original model,damage indices at failure state of tests calculated by the modified model have mean value closer to 1 and smaller scatter,and the damage level of RC structures can be better reflected by the modified model.At last,the value of combination coefficient is recommended for ordinary RC members in building structures.

Abstract:This paper presents parametric vibration of a system of a horizontal cable with sag and a mass block representing a bridge deck section under axial harmonic excitation.The differential equations of the cable and the mass are established.By using the variable separation method to cable’s cross displacement and taking the first two modes of the cable into account,the differential equations governing the motions of the first two generalized coordinates of the cable are derived based on Galerkin method.On the basis of the theoretical model,the theoretical solutions of the differential equations of the cable-deck system are derived with multiple-scale method.Taking Cable A20 of No.2 Nanjing Bridge over Yangtze River as an example,the vibration characteristics of the system is numerically investigated and the validity of the theoretical solutions is tested.

Abstract:Based on superpositon principle and the orthogonal expansions of Bessel eigenfuncion,the analytical solution to radial temperature of circle tunnel in cold region was obtained subject to time and distance dependent boundary changes of the third kind.The analytical solutions of the annual mean temperature and temperature amplitude were obtained by energy banlance method and experiential method with a consideration of heat conduction/convection between the tunnel ground and the air flow in the tunnel.The annual mean temperature presented an exponential growth with the increasing distance from entry of tunnel,the annual temperature amplitude a negative exponential growth.Applicablity and accuracy of the equation were examined by comparing the calculated results with the mesaured results.It is found that the calculated values agree well with those measured in the field.In determining the temperature distribution outside the tunnel,wind speed and thermal properties parameters of surrounding rock,the axial and radial temperature can be calculated with the analytical solution.The necessary length of anti-icicle treatment from tunnel entrance area can also be determined.The analytical solution proves to be useful for engineers and technicians.

Abstract:A research was made on the application of intelligent total station to piling position of near-shore,and a new practical model for piling position is introduced.Azimuth and tilt of piling can be obtained by an equipment on ship.For circle piling position,the tangential direction of the piling side (including horizontal angle and vertical angle) and the three-dimensional coordinates of one point on piling surface have to be surveyed.For square piling position,only one point on piling edge needs a survey.According to the mathematical model,the software is realized based on the EVC and the WinCE-based Topcon GPT-7502 intelligent total station.Observations can be transmitted to the ship by radio.Personal digital assistant(PDA) at ship receives the data and shows it by graphic,which can guide the movement of the piling ship.Field test on practical project verifies the correctness of the model and methods.

Abstract:Through a series of pullout tests under different vertical stresses,a study was made of the mesoscopical behavior of the interface between two-way geogrid transverse rib and sand based on digital visual tracking technology and no punctuation soil deformation measurement techniques.The interface being traced with the techniques of no punctuation soil deformation measurement,a quantitative analysis was made of the changes of interface movement.Analysis results show that the apparent friction coefficient is related with the vertical stress.Mesoscopical results show the upper interface thickness of transverse rib and sand is different from the lower.In whole,the upper thickness is greater than the lower,and the rib on the interface motion is more intense.The mesoscopical displacement strain plot shows the rib damage model of this research is similar to the piercing damage model proposed by Jewell,but the upper part is slightly larger than the lower of the regional area.Jewell piercing damage model is basically authenticated.

Abstract:Based on the two-phase flow theory,an improved Reynolds stress model(RSM) turbulent model is presented as to stimulate the snow drifting around a cube model.In order to represent the influence of snow particles on the wind field,extra source items are added both to the momentum equations and RSM turbulent model.Comparison of the mean wind pressure on the surface of the cube between obtained results and those through field measurements are presented as to evaluate the suitability and effectiveness.Then snow drifting results predicted by the improved model are compared with the results from the previous researches.It is found that the present results agree well with those through the field measurements,such as the trends of erosion/deposit of snow particles around cube are similar.The simulated results show erosion appears in the windward region,as well as in the separation region at both sides.While deposition appears in the leeward region.

Abstract:Based on a multi-functional office building model,the most unfavorable fire scenario was simulated.According to fire smoke emergency critical value,a hybrid field-network model was established to simulate the fire smoke flow properties in building and the available safe egress time(ASET)was obtained.The required safe egress time(RSET)was calculated by the evacuation simulate system developed independently by Chongqing University.The occupant safety evacuation in building fire is evaluated through a comparative study of the RSET and the ASET,and measures are proposed about the safety evacuation.

Abstract:As the development of computer technology,auralization method is widely conducted in subjective experiment.ODEON,an acoustic software which can simulate the sound field nicely,was used as a tool to compare the speech intelligibility between large-volume space and long space.The results indicate that in the same space the early-decay-time performs more prominently than signal-noise-ratio.As a result,the early-decay-time is proposed to be designed as the main parameter and be less than 1.5 seconds in rooms where the main target is to obtain a high speech intelligibility.

Abstract:Curve fitting method is the most common method to determine the parameters of the transient flow pumping tests,but its main drawback is that curves are often rely solely on individual manipulation.Based on curve fitting method,a modified BP artificial neural network is used to solve the approximately analytical solutions of Theis equation for the problem of the unsteady flow of fully penetrating wells in confined aquifers,and the curve fitting-based BP artificial neural network is proposed.It avoids inappropriate trained range.It also reduces the network topology with a simpler artificial neural network structure,as this can reduce training time,improve network generalization and prevent over-fitting.The case calculating results indicate that the proposed BP artificial neural network is an efficient method to solve hydrogeological parameters by utilizing the pumping test.Furthermore,the proposed BP artificial neural network could be used widely in the solution for hydrogeological issues.

Abstract:Evaluating indicators and criteria of high-viscosity modified asphalt are key factors that have significant influence on the performance of open-graded friction course.Tests for asphalt penetration and soften point,vacuum capillary viscometer test,dynamic shear rheological test,wheel tracking test and cantabro loss test are applied to select suitable indicators of asphalt binders for rutting resistance and durability evaluating of open-graded friction course.The test results and analysis show that zero shear viscosity at 60℃ and soften point are significantly related with dynamic stability and scattering loss obtained from wheel tracking test and cantabro loss test,and both indictors are suitable for evaluating the performance of high-viscosity modified asphalt as a result.Besides,dynamic stability no less than 4 000 cycles per millimeter,and scattering loss no more than 15 percent are suggested as the criteria of open-graded friction course.Correspondingly,zero shear viscosity of asphalt binders at 60℃ should be no less than 40 000 Pa·s,and soften point of asphalt binders should be higher than 85℃ to ensure the performance of asphalt mixture.

Abstract:Based on the method of the gray system theory,the prediction models of pavement structure strength index,pavement conditions index and the pavement roughness are obtained respectively.The prediction models are validated and modified through the actual road test data,and compared with the traditional model of regression analysis.The results show that for predicting such discrete target value of pavement surface condition,the gray prediction method can improve the accuracy,and meet the requirements of pavement performance prediction.

Abstract:Conventional traffic prediction models are time-consuming and arduous.Since the traffic of Indiana is stabilized,the Ordinary Kriging,inverse distance weighting(IDW) and radial basis functions(RBF)interpolation methods were used to predict the traffic of Indiana based on ArcGIS software.With the comparison of the prediction and weigh-in-motion(WIM) Systems,the results show that the inverse multiquadric spline(IMS)interpolation of RBF interpolations is suitable for Indiana traffic distribution and the actual prediction error is minimum.

Abstract:According to the characteristic of the driving environment of the expressway tunnel,the length research scope of the tunnel section was established.Based on the risk ingredients of tunnels and the selecting principles of the evaluation index,the main factors of the tunnel driving environment were analyzed by using Delphi and clustering analysis method.A safety evaluation index system of tunnel driving environment was established,which contained three arrangements with six sub-factors in two aspects including road environment index and climate environment index.And the indices were analyzed and contrasted.The evaluation index system can be applied to the analysis and evaluation of the driving environment of expressway tunnel.

Abstract:In this study,a set of optimal maintenance fund allocation models are established to cope with different desirability levels of pavement conditions at the network level for asphalt pavements.Corresponding to low,middle and high levels of pavement condition desirability,the proposed fund allocation models can adapt to the decision-making processes of the authorities and reduce the computational burden.Case studies indicate that the models can effectively solve the pavement maintenance fund allocation problems.This study also shows that classifying the pavement condition desirability levels and establishing corresponding analysis procedures can provide solid foundations for the future demand of maintenance funds.

Abstract:The adsorption of Congo red from solution was conducted by using steel slag as the adsorbent.The effects of initial concentrations of Congo red,slag dosages and its particle sizes on the adsorption process were investigated.Under the tested condition,steel slag was observed to adsorb above 95% Congo red,and the adsorption process was not affected by pH and temperature.The amount of dye adsorbed per unit weight of steel slag increased with increasing initial concentrations of Congo red,while decreased slightly with the increase of slag dosages and particle sizes.Kinetic and isotherm studies showed that the adsorption process followed the pseudo-second-order kinetic model and Freundlich model respectively.Compared to the adsorption of cationic dye onto slag,the adsorption amount of slag followed the sequence of Malachite Green(cationic dye)>Congo red(anionic dye)>Methylene(cationic dye).Analysis results from Fourier transform infrared spectroscopy(FTIR) and scanning electron microscope(SEM) reveal that the adsorption processes are correlated with the combination ways of dyes onto slag surface,depending on the formation of crystal.

Abstract:The original ecological footprint model was based on counting consumption of resources,and the consumptive ecological footprint and productive ecological footprint were introduced to overcome the deficiency in evaluation of regional sustainability.And then a case study was made of the Suzhou city,the sustainable development status and eco-economic system development capacity from 1993 to 2002 were assessed and analyzed.The results show that the productive ecological deficits per capita are all less than that of the global 0.4 hm2,while the consumptive ecological deficits per capita are more than that of the global.The ecological environment is regional sustainable but unsustainable relative to the world,and the ecology efficiency increases year after year.The ecological footprint diversity indexes remain stable and the eco-economic system sustainable development capacity increase year after year.The effective way of increasing sustainability capacity is to increase ecological footprint diversity.The resized model and measurement method of sustainable development capacity proposed could better evaluate sustainability of a region.

Abstract:Due to the unique geometry of hooked end steel fiber(HSF),frictional pullout energy of HSF and plastic deformation energy of steel fiber hooked end during fiber pullout process were theoretically derived,respectively.Then,energy superposition principle was adopted to calculate the total energy consumption during HSF pullout process.Good performances that were obtained in comparison with experimental results of single HSF pullout test well support the validity and accuracy of this proposed model,which indicate applicability of this model to a further prediction of fracture energy of hooked end steel fiber reinforced cementitious composites (HSFRCC).

Abstract:A study was made of the carbonation,chloride ion penetration and alkali-aggregate reaction (AAR),frost-resistance and adiabatic temperature rise of concrete with compound mineral admixture(CMA) of steel slag,granulated blast furnace slag and fly ash.The result shows that the resistance to carbonation and chloride ion penetration and expansion caused by AAR of concrete can be improved obviously in comparison with ordinary concretes at the equal water/binder ratio by substituting CMA for cement at equal quality,and the frost-resistance of concrete decreases dramatically with CMA over 50%.The hydration heat of cementitious material,adiabatic temperature rising and the rising velocity decrease remarkably with CMA substitute for cement.

Abstract:Magnetic nanoparticles (Fe3O4) ranged from 72 to 447 nm were synthesized by the solvothermal method at 180 ℃ with FeCl3·6H2O and ethylene glycol as reactant and double surfactant.The influence of NaAc·3H2O and other factors were studied.The synthesized magnetic nanoparticles were investigated in detail by powder X-ray diffraction(XRD),FT-IR Spectromete(FT-IR),transmission electron microscope(TEM),scanning electron microscope(SEM) and vibrating sample magnetometer(VSM).The results indicate that NaAc·3H2O is guidance and dispersant,the size of Fe3O4 is influenced by reacting time,iron source concentration and the amount of surfactant.The synthesized Fe3O4 particles show excellent magnetic property,which makes them have potential values in bio-medicine.

Abstract:The effect of single one-and two-atom vacancy defects on the tensile mechanical properties and deformation mechanism of the zigzag and armchair single graphene sheets was investigated using molecular dynamics simulation with Tersoff bond-order interatomic potential.The numerical simulation results show that there is no effect on the Young’s modulus of the graphene due to the presence of vocancy defects,but there is a reduction in the tensile strength and failure strain.One-and two-atom vacancy defects are observed to reduce tensile stresses by as much as 8.10% and 6.41%,respectively,and markedly reduce failure strains.The defects also affect the deformation mechanism of graphene sheets under tention.In most cases,defects serve as nucleation site for fracture.

Abstract:According to the definition of link substructure in component mode synthesis (CMS) method,link substructure is essentially a kind of super element with the interface degree of freedoms(DOFs).A new technique of free-interface CMS,compatible for both displacement and force on interfaces,was then presented,by transforming link substructure into super element with Guyan static condensation or dynamic condensation.The new technique not only retains free-interface CMS’s advantages of reducing the system DOF efficiently and high accuracy,but also can deal with lumped damping reasonably,thus,it has a widespread application in dynamic analysis of the structures with local non-linearity.Then,the application of the proposed technique was shown by modal and seismic response analysis of a truss bridge in which the girder and brace are lead rubber bearings (LRB) linked.Regarding LRB as super element link substructure,the calculation accuracy and efficiency of Guyan and dynamic condensation methods are compared with finite element method (FEM) or direct integration method.Furthermore,inherent characteristic results of the truss bridge under different LRB disposition forms were obtained.

Abstract:An analysis is first made of the dynamic behavior of the large diameter slurry shield’s bubble cabin.Based on the mathematical model of gas-pressure spring according to the effect of pulsating pressure,formula to calculate the parameters such as the initial volume and initial pressure of the gases in the bubble cabin which is the key factor to the excavating face-pressure-balanced control system is achieved,and the range of these parameters is also discussed,which is the basis of the control-system design.The ultimate conclusion,initial mud level in the bubble cabin should be maintained at the shield central axis,is consistent with the actual construction.

Abstract:The purpose of this paper was to investigate the effective use of the minimum outdoor air ventilation rate using computational fluid dynamics(CFD)methods in residential buildings with low cooling load,where a chilled ceiling in combination with a fresh air handling unit was adopted.Some thermal environment parameters such as air speed,temperature,relative humidity,concentration of pollutants were obtained under three kinds of air distribution such as mixing ventilation,displacement ventilation,underfloor air supply.And the comprehensive evaluation of the indoor air quality and thermal comfort level of three kinds of air distribution were also given.The results show that when displacement ventilation or underfloor air supply is adopted,the better indoor air quality will be obtained,and the minimum outdoor air ventilation rate will be used more efficiently.

Abstract:When blast furnace gas turbine is suddenly stopped in large iron and steel enterprises due to the fault,gas pressure along the pipeline will steep rise for mutation of extra large gas flow,and this will lead to the security incident of gas leak as a result of water sealing breakdown.This paper presents a dynamic analysis of this typical malfunction condition by using compressible fluid high-order finite volume method(FVM) and its improved algorithm.The FVM method is a higher level supplement on characteristic method and finite difference method usually applied to the dynamic analysis of gas pipeline network.And the improved algorithm of semi-implicit method for pressure-linked equation(SIMPLE) which is more stable in FVM can overcome difficulties such as the great differences in the size of diameter and gas flow mutation at the joint of pipes.

Abstract:Under the background of contradiction between demand and supply of energy as well as the policies of developing rural areas,rural energy system construction is emphasized.Investigation data of 10 typical villages from severe clod area,cold area and hot summer and cold winter area are conformed.The categories and characters of local rural residential energy consumptions are generalized.Influencing analysis of rural energy consumption related to the other social factors are computed by software of Matlab,and correlation of each factors are finally acquired.

Abstract:A cyber-physical system (CPS) is a system featuring a tight combination of and coordination between the system’s computational and physical aspects by communication networks.It is the development product of computer and network technologies and gains much attention from governments,academia and industry.In order to design and opearte CPS effectivley,scientists and engineers in computer science,control science and communication science should work together to overcome the challenges such as theories,design methodologies and tools.

Abstract:This paper discusses the problem of the accurate geometric correction based on line features for SPOT imagery.On the basis of researching the use of SPOT images’ ephemeris parameters,satellite ephemeris parameters are proposed to be adopted to determine initial parameters of correction model.Then,accurate parameters are obtained by means of iterative calculations,while the linear equations are used as the set of constraint conditions for the correction model,and precise correction of SPOT imagery is achieved by using the accurate parameters of the correction model.The experimental results show that the geometric correction method of SPOT imagery based on line features can meet the accuracy of digital orthophoto in 1∶50000.

Abstract:After an introduction to the principle of floating car data (FCD),this paper puts forward the operation flow of preprocessing on FCD,and the algorithm of map-matching as well.Based on an analysis of the percentage of coverage of FCD on the road network,large quantity of heritage database of routing status is used to estimate the routing velocity when lack of FCD on parts road segments.Multi-linear regression model is then adopted by considering the spatial correlativity among the road networks,and some model parameters are determined when time interval is classified in day and week.Besides,error of velocity probability and error of status probability are achieved based on the result from field testing,while the feasibility and reliability of the velocity estimation model is obtained as well.Finally,as a case study in Shanghai center area,the whole routing velocity in the road network is estimated and published in real time for public.