Abstract:Through definition of design service life for bridges and their elements,components classification according to structural systems,durability type research as well as investigations of their actual operating lives and recommended design service lives in specifications home and abroad,a direct method and also a simplified one were proposed to determine design service life of bridge structural elements based on the life-cycle cost analysis.As for direct method,element service life schemes were established,and then the one with optimal economy can be selected through life cycle cost calculation of each scheme.As for the simplified method,a calculation formula was presented for classification and evaluation of the influence coefficients and foundational design service lives of bridge elements were recommended based on professional investigations.Finally,a sea-crossing project was taken as an example to illustrate the process of design service life determination for bridge structural elements.

Abstract:This paper presents a bi-parameters structural vulnerability analysis method with the damage consequence and the relative magnitude of the damage scenarios to the structural system as two parameters.The proposed method was applied to the study of the cable-stayed bridge vulnerability to cable failure scenarios by taking the minimum stability factor and the maximum stress safety factor of the main girder as the structural performance measurements.A case study was made of the cable-stayed bridge to illustrate the proposed method.The vulnerable scenarios with a higher consequence but lower magnitude were found.The simulation revealed the structural sensitivity to cable failure scenarios.The analysis results can thus be referenced for designing the structural members to be monitored and the sensor allocation of a structural monitoring system.

Abstract:The hot spot stress distributions and stress concentration factors (SCF) of welded truss T-joints made of circular hollow section braces and concrete-filled circular hollow section chords (so-called CFCHS joints) under axial tension and compression and in-plane bending on the braces were investigated experimentally,which is a foundation for fatigue assessments of the joints.The measuring method and results of hot spot stresses on the CFCHS joints were discussed and compared with those on the welded T-joints made of circular hollow section braces and chords (so-called CHS joints) to examine the difference in behavior of the two kinds of joints.The current research points out that for the CFCHS joints the linear extrapolation method can be used for chords,whereas the quadratic extrapolation method must be used for braces.The hot spot stress distributions on the CFCHS joints tend to be more uniform and their SCFs become smaller significantly,compared with the CHS joints.Axial tension on the brace puts the CFCHS joints at a disadvantage,which produces higher SCFs than axial compression.The effects of nondimensional geometric parameters β, τ and γ on SCFs of the chords of the CFCHS joints are basically the same as those of the CHS joints,but for the braces,there is a bit difference in the effects of parameters β,τ and γ between the two kinds of joints.Concrete has the function of improving the CFCHS joint rigidity and then decreasing SCFs which is expected to increase fatigue strength,but concrete strength grade does not exert significant influence on SCFs.

Abstract:A centrifuge model test was made on an embankment with lime-stabilized soil as backfill on undisturbed soft soil,and an analysis was made of the in-flight photographs, displacements measured by displacement sensors installed on the surface of embankment and ground, and displacement contour lines obtained from the markers installed on the front face of the clay.The results show a vertical crack occurs to the embankment during its construction from the height of 2~4 m due to differential displacement of subsoil. The ratio of the maximum lateral displacement increment in the subsoil to the ground settlement increment at the embankment center changes significantly during the loading stage of the height of 4~6 m in prototype, indicating the subsoil tends to fail. This finding is consistent with the observations of the centrifuge test and the computation result from Terzaghi’s bearing capacity theory using undrained shear strength. In view of the brittle behavior and low tensile strength of embankment with lime-stabilized soil, low embankment of the height lower than 2 m is recommended for practical projects.Reinforcement in the embankment is also recommended for improving the integrity and tensile strength and reduce the differential displacement of subsoil as well.

Abstract:Based on different tensile-compressive modulus theory,a finite element program is compiled and verified by a plane-stress circular ring problem.This paper presents an analysis of the stress and deformation state of supporting structure in a typical tunnel section and also the change rule of stress field and displacement field variation with different modulus coefficients.Results show that the variation of different modulus coefficients has little impact on the displacement field of linear structure and the axial force of anchor,but a great influence upon the stress field of tensile zone,which offers a new theoretical basis for tunnel supporting structure design.

Abstract:According to the features of the test of buoyancy on shallow underground structure,a model test system which directly determined the hydrostatic buoyancy on the bottom-board of the structure was developed.Main system parameters were determined based on the principle that the uplift pressure equalled the hydrostatic pressure in pure water.The buoyancy on the bottom-board of the model cellar at different embedded depths in pure water,saturated gravel,medium sand,fine sand,silt and clay were determined by the system,as well as the pore pressure.The test results show that the system’s maximum error rate of pure water buoyancy test is less than 1%.The buoyancy on the bottom-board in saturated gravel,medium sand,fine sand and silt are about 5% less than that in pure water,whereas the buoyancy in saturated clay is equal to that in pure water. During the filling of saturated silt and clay,the buoyancy is so great that it may exceed the weight of the displaced saturated soil.During the process of filling,the water heads of all piezometers are higher than the surface of the soil. Moreover,the deeper the piezometer is ebedded,the higher the piezometric head will be.At the long-term stable state,the water heads of all piezometers in clay and nonclays are exactly as high as the filling surface.

Abstract:Building-energy-use factors can be divided into two types according to their effects on energy efficiency:efficiency-correlated factors and efficiency-non-correlated factors.The energy-use only derived from efficiency-correlated factors affects the practical building energy efficiency,which is the basis for building renovation.This part of energy-use is defined in this paper as equivalent energy consumption of building energy efficiency.And an equation of equivalent energy consumption of building energy efficiency is developed by means of multiple regression analysis.With a sample of 33 office buildings ranged from 20 000 to 80 000 m2 in Shanghai,an equation of equivalent energy consumption of building energy efficiency is given.And the cumulative frequency curve of energy efficiency is also given for Shanghai.

Abstract:An analysis was made of the operation environment in terms of the road facilities,traffic environment and climatic environment to ensure pivotal infrastructure security. According to the relationship between driving behavior and operation environment,a description model was established to describe the characteristic of road division and operation environment attributes. Based on an analysis of the significant influence factors,five characteristic indexes including alignment safety,pavement performance safety,cognitive character of traffic sign,validity of traffic safety facilities ,risk of climatic environment and related assessment contents were proposed. At last,rules of comprehensive index changing with the risk index were proposed for an analysis of the operation environment safety.

Abstract:When catastrophic incidents such as earthquake happen,one or several links may lose its (their) functions totally.Then whether the network and origin-destination(OD) pairs are still connected becomes the most critical problem.Therefore,this paper presents a study of the road networks’ abilities to undergo incidents from the point of view of its topology.The assessment index “mincuts frequency vector” prevailing in the field of telecommunication is intreduced into the assessment of topology vulnerability of road network.Since this index is comparable between different networks,it can reveal the structure characteristics with a consideration of the difference of links’ abilities to undergo incidents.The definition and algorithm of the index are described by trial networks.The results are then used for the identification of critical links.With consideration of the links’ abilities to undergo the incidents,the index is adopted to evaluate the effect of improving critical links.

Abstract:A traffic network evolution model and algorithm to disclose the traffic network evolution laws were proposed according to microscopic dynamics and macroscopic mechanism based on the dynamic interaction mechanism between traffic system and urban spatial structure,and the internal operation mechanism of traffic system.In the short term,the road users externality was taken into account to formulate objective function;furthermore,an optimal traffic network model was established. In the long run,the dynamic interaction mechanism between traffic system and urban spatial structure and the design idea of evolutionary rule of scale-free network were combined with the economic relation concept to design traffic network evolutionary rules and to characterize evolutionary mechanisms.Experiments show that with the network evolving,hierarchy emerges and turns clearer,and what is more significant is that the total network cost decreases in the process;the computation of a new network entropy defined by betweenness centrality illustrates that the network entropy becomes smaller and the traffic network evolves to a more orderly structure with improving performance.

Abstract:Based on the finite difference method,a study was made of the convergences and meshing technique for pavement temperature field in different boundary conditions.Also an analysis was made of the feasibility and calculating error for pavement temperature field in a multi-layered system being simplified to a homogeneous semi-infinite body,the error between the first order Taylor approximation of pavement surface temperature,sky effective temperature due to mutual radicalization in pavement surface and sky and actual temperature.The influence of the estimated error for sky effective temperature on pavement temperature field and the dispersing time of initial temperature error were discussed.

Abstract:The staging characteristics of the decision-making process was captured and used to divide the task of project scheduling and prioritization into two processes,namely,maintenance fund allocation and project prioritization.A bi-level program was then constructed to model the decision-making process.The techniques of dynamic programming and genetic algorithm were applied to solving the bi-level model and the deficits of conventional methods were overcome as illustrated in the applications.

Abstract:An analysis was made of the space of the different types of railway stations in Shanghai by means of the space syntax with a consideration of the space integration value,the characteristics and conflict point of streamlines as well as the apperception of the pedestrian.Then the safe area from fire was determined,and the railway station platform evacuation procedure was proposed to be divided into two stages when an accident such as a fire happened,and each stage should be provided separately evacuation time requirements.These proposals are helpful for a future amending and perfecting of“Railway Design Manual”on emergency evacuation.

Abstract:Two different methods of water quality reliability analysis under booster chlorination were presented，namely,a simplified method based on desired chlorine residual which brought in water demand variations and used the theory of linear superposition,and a new method based on chlorine residual coverage rate.The reliability analysis of water quality under booster chlorination was carried out within a water distribution network using these two methods.The results show that booster chlorination can maintain a high reliability without impairing its advantages in allowing a lower average chlorine and decreasing the variability of chlorine residuals which lead to a lower total dosage.

Abstract:The paper presents a research on the degradation of bensulfuron-methyl and microbial characteristics in rhizophere soils with different riparian plants.The research results show that there exist significant differences in microbial degradation dynamics of bensulfuron-methyl in the rhizophere soils among three kinds of riparian plants.Acorus calamus shows a significantly higher degradation efficiency of bensulfuron-methyl in the rhizophere soils,Zizania aquatica cames the second and Phragmites australis the last one.Residual bensulfuron-methyl content in Acorus calamus rhizophere soil is 23.1% and 32.2% lower than that in Zizania aquatic and Phragmites australis rhizophere soils,respectively.Due to bensulfuron-methyl addition,the activities of the dehydrogenase are stimulated firstly,and then are inhibited,and finally recovered to the initial level,while the activities of the phosphatase and urease show a significantly decreasing trend.Bensulfuron-methyl addition significantly decreases microbial numbers in the rhizophere,especially for bacteria and fungi.Acorus calamus shows significantly higher enzyme activities and larger microbial numbers in the rhizophere soils,as compared to Zizania aquatica and Phragmites australis,which means that Acorus calamus has a better buffer performance to bensulfuron-methyl addition,and a greater improvement effect on microbial degradation of bensulfuron-methyl in the rhizophere soils.

Abstract:The characteristics and behaviors of soluble microbial products (SMP) in membrane bioreactors (MBRs) were investigated at various sludge retention times (SRTs) by four paralleled laboratory-scale MBRs.The fouling potential of SMP and the extent of SMP accumulation were found to significantly increase with decreasing SRT.The molecular weight(MW) distributions of SMP generally exhibited a bimodal pattern with high MW components became more evident at long SRTs.Similar molecular weight distributions of SMP in MBRs and in effluents were observed.Carbohydrate appeared more prone to accumulate in MBRs than Protein,especially at short SRTs.Results above suggest that in a comparison of the tendency to cause membrane fouling,carbohydrate is higher than protein,and components of SMP with larger molecular weight appear to have higher tendency than that with smaller molecular weight.

Abstract:MSWI fly ash was used as a major cement raw material in sintering sulphoaluminate cement clinker successfully in the laboratory.An investigation was made into the sintering system,mechanical performance,hydration process and microstructure of the clinker based on the X-ray diffraction(XRD),scanning electron microscopy (SEM),X-ray fluorescence spectrometry(XRF).The result shows that the clinker can be sintered properly between the temperatures of 1 200 ℃～1 300 ℃ and sintered time of 120 min.Cl- content in the clinker made with MSWI fly ash is about 1.08%.However,most Cl- cannot leach out in water solution from the hardened cement paste during curing age between 1 d and 28 d because of the Cl- being combined in clinker minerals and its hydrates.The compressive strength of the sulphoaluminate cement was high in early age while developed smoothly in later age.

Abstract:Different carbonized concrete specimens were obtained by rapid carbonization test and their chloride diffusion coefficients were tested and calculated by rapid permeability test.The results show that there’s no obvious difference between chloride diffusion coefficient of totally carbonized concrete and that of partly carbonized concrete while that of non-carbonized concrete is higher than the former two.It can be concluded that there exits substantial benefits of reducing the chloride diffusion coefficient by concrete’s carbonizing; concrete’s carbonizing increases concrete’s density to some extent by reducing the porosity. The chloride diffusion coefficient of totally carbonized specimen is about 1/2 that of non-carbonized specimen. This paper also introduces a method by using pH device to measure the pH of different carbonization degree concretes and offeres the changes of the pH.

Abstract:A vehicle stability control based on hierarchical control approach was introduced.Through the Weighted Least-Squares (WLS) control allocation algorithm,the longitudinal force of each tire (motor torque) was distributed considering the constraints to form the direct yaw moment.The experiment results show the respective longitudinal force of the four wheels has been effectively distributed according to the status of each wheel.And also the vehicle’s yaw rate can follow the reference yaw rate excellently.The vehicle’s yaw rate and lateral acceleration have been reduced,meanwhile,the vehicle handling and stability have been enhanced instead.

Abstract:The flow quality of automotive wind tunnel test section can be improved by decreasing the axial static pressure coefficient.Both test results and numerical results show that the axial static pressure coefficient can be improved by increasing the collector angle or increasing gap of collector throat,and their effects become more and more obvious with larger collector angle and larger gap of collector throat.In addition,the influence of the axial static pressure by only increasing the collector angle or only increasing the gap of collector throat,and increasing both of them are compared.These findings can help to improve the axial static pressure of full scale automotive wind tunnel.

Abstract:To improve the effectiveness of tearing algorithm of coupled activity set,a new tearing criterion is presented in view of the disadvantages of the existing algorithms.In its construction process,the relations between two resources were analyzed by the analytic hierarchy process(AHP) method based on triangular fuzzy number,and the relations between resource and activity were analyzed through degree of cross-correlation.Then the relations between two activities were analyzed through degree of autocorrelation.Finally,by defining a comprehensive index,a new method to tear coupled activity set was proposed.Its effectiveness was demonstrated by an illustrative example showing the improved design of overhead crane.The results show that this method not only effectively ensures success in the resource-constrained design process,but also gives the guidance for the fast resource-scheduling.

Abstract:The paper presents a multi-enterprises collaborative planning system based on VirtualHub,which is developed to support the share of production data.Message passing mechanism ensures the information transfer among the multi-enterprises,and gets rid of the complexity of information sharing between isomerous systems.Orders are decomposed broadly based on group technology,and then fractionized further.Finally,a case study on order decomposition,subtask updating and monitoring validates the the system and method.

Abstract:Object-Oriented Petri Net (OOPN) was integrated by Object-Oriented Modeling (OOM) and Petri Net,as a result,the structure of system model was simplified and the reusability and scalability were enhanced by utilizing the encapsulation and succession of the object.The model of OOPN is composed of OPN and CPN,the former describes the internal specifics of the object and the interfaces between the interior and the exterior,the latter describes the relations among the objects in the system.This paper introduces the application of OOPN to system modeling,and shows how to build an OOPN model by modeling an Elevator Group Control System (EGCS) with a consideration of the scheduling of Elevator Group Control.

Abstract:Multi-base line photogrammetry with big rotation angles is needed to obtain the information of the target.The paper presents formulas of dependent relative orientation in multi-base line photogrammetry.With the baseline components and direction cosines as the parameters,photos can be taken at any place and with any rotation angles,without any limitation on the initial values.And also another method is introduced to solve the same problem.The experiments with no-metric cameras on experiment field prove that the elements of relative orientation can be correctly calculated with both of these two algorithms.

Abstract:Positioning results may be influenced by different unavoidable errors such as space correlation errors,time correlation errors and so on,though ionosphere-free combination model can somewhat diminish the effects of ionosphere delay,and the orbit error can be modified more or less by the precise orbit.Based on the theory of precise point positioning,the paper presents a dscussion on the characterization of troposphere delay by adopting the data collected in different sample intervals,and also analyses of the variation of epoch-difference values of troposphere delay with the variation of sample intervals.Finally,the paper presents a study of the effects of troposphere delay on the observation of epoch-difference,the effects of residual errors on the position-difference and observation combination,and the variation of residual errors with time.

Abstract:An analysis was made of the major factors causing loss of correlation in permanent scatterer synthetic aperture radar differential interferometry.A method considering atmospheric delay variety differences was adopted to optimally select the common master image for PSDInSAR.Its specific function model,modeling principle and solution were provided.The original data came from continuous GPS permanent station and ENVISAT satellite ASAR images in Tianjin area from European Space Agency.Based on Bernese 5.0,Matlab7.1 and Shell programs,a test is made on the optimum selection of common master image fusing GPS data.The experiment shows the model correlation coefficient method fusing GPS data can select the optimal common master image from many SAR images rapidly and correctly,which guarantees the high-precision of PSDInSAR deformation survey.

Abstract:By synthesizing the advantages of various surveying systems at home and abroad,a simply-operated highly automatic visual surveying system was developed with a characteristic of automatic shield tunneling guiding survey visualization and engineering dynamic management visualization.The system was applied to the railway construction.Result shows that the surveying system is convenient,accurate and feasible to automatically accomplish the whole measurement task.Based on the visual information of the correlations offered by the system about the TPM site and the building around,accidents caused by surroundings during the tunnel construction can be avoided.

Abstract:The real-time data of all 12 monitoring station sites obtained by kinematic Global Positioning System (RTK GPS) were analyzed and computated,and the spatial distributions and related spectrum estimations for monitoring station sites were presented.An analysis was also made of the characteristics of structural performance and its development tendency of the spatial distribution and the spectrum distribution of structural response.The research show that statistical and spectrum analysis of response is a feasible method to reveal the characters of structural response.The statistical characters of structural response can be regarded as index for estimation of structural performance difference.