Abstract:

Abstract:The capacity and stiffness of the steel frames are improved significantly considering slab composite effect which may cause bad effects on the seismic.Efficient and accurate FEM of ABAQUS was proposed for numerical simulation.And the selection of elements types, the material stressstrain relationship and damage model were made a detailed description.Nonlinear finite element model was approved with existing steel framecomposite connections quasistatic test home and abroad.It is shown that the capacity of this type connections is improved by nearly 26% and the stiffness by 30%.And this type of connections have more full hysteretic curve with high energyconsuming ability and good seismic performance.

Abstract:Immersion in sodium chloride solution was adopted to periodically test chloride ion concentration at the surface of concrete and regression analysis was completed.And timedependent law of surface chloride ion concentration of concrete with time was investigated.Influences of sodium chloride solution concentration, water to cement ratio and fly ash content on size and accumulation rate of surface chloride ion concentration were also analyzed.It is found that surface chloride ion concentration gradually grows with the of time increase the of time and reaches a steady state finally.With the increase of sodium chloride solution concentration, surface chloride ion concentration reaches the steady state more quickly and then increases numerically.Bigger water to cement ratio means quicker accumulation of surface chloride ion concentration and greater surface chloride ion concentration.Fly ash replacement could fasten accumulation of surface chloride ion concentration and surface chloride ion concentration increases with the increase of fly ash content.An improved model was proposed by comparison and correction of current models.

Abstract:In order to study the stability of foaminplace cavity wall, the capacity of reinforced concrete strip ear and tie involving in cavity wall deformation, the broken shapes and mechanical performance of the cavity wall, the effective measures was seaked to improve deformation capacity and overall performance of the cavity wall.13 patches of cavity wall and 1 patch of solid wall were built and seismic tests of which were carried out.The lnfluence of some constructional measures on mechanical behavior and deformation properties of the wall and vertical pressure and insulation layer thickness on the relative displacement difference of the internal and external wall of foaminplace cavity wall was analyzed.Finally, the capability of reinforced concrete strip ear and tie working interactively between the internal and external wall of foaminplace cavity wall was analyzed.It is found that deformation capacity of the cavity wall is improved efficiently with constructional column and the high bonding strength, shearing strength and pressure strength of foaminplace insulating mortar have certainly a positive influence on the bearing capacity of the wall.The reinforced concrete strip ears play the leading role in reinforcing connection of the internal and external wall of foaminplace cavity wall and guaranteeing outplane stability of the external wall.When walls crack seriously, the ties can play an important role in supporting and drawing the wall and preventing wall collapse.Furthermore, the reinforced concrete strip ears and ties which are the main construction measures to coordinate the internal and external wall work together perform a great variety of tasks.Therefore, the reinforced concrete strip ears and ties should be designed rationally to guarantee playing their respective roles.

Abstract:In order to study the mechanical behaviors of irregular joints in rigid steel frames which had been used in largescale power plant, 6 specimens in 1/4 scale of the prototype model were designed according to different axial compression ratio and section height ratio of beams and were tested under low cyclic reversed loading.Based on the failure law of specimens, the main factors that affect the bearing capacity of the irregular joints were analyzed.By the division of panel zone, the calculating formula was put forward according to mechanical principles.It is found that the difference between calculating results and experimental results is about 18%.And the proposed method for calculating the irregular joints in rigid steel frames is feasible.

Abstract:The experiments were carried out to investigate the behavior and strength of tube–gusset connections with 1/4 annular ribbed plate.Based on the FEM, the strength of tube–gusset connections with different thinwall, different width and thickness of ribbed plate and modes of ribbed plate was analyzed.The calculation method of ultimate strength were proposed.It is found that the thickness of tube and the width and thickness of ribbed plate have evident influence on the strength of tube–gusset connections with ribbed plate with the conditions of tube and ribbed plate.

Abstract:The experimental results of reinforced concrete sandwich beamcolumn joints were studied intensively and finite element method simulation of such joints were performed for the sake of design method.Basic design criterion and computation contents were provided according to failure mode of specimens and other experimental results.And the limits of parameters were proposed based on the analysis of seismic behavior influence factors and comparison of traditional joints and sandwich joints.Hence, formulas of load resistant capacity were acquired by the results of load resistant capacity of specimens and nonlinear finite element method simulation.It is found that three measures should be taken for sandwich joints in order to reach demanded ductility and load resistant capability.Firstly, several parameters should be limited, including shearcompression ratio, axial load ratio, ratio of beam concrete strength to column concrete strength, and minimal amount of transverse reinforcement of joint.Secondly, shear load resistant capacity and axial compressive load resistant capacity should be computed to ensure load resistant capability of joint, and essential strengthen measures could be applied if necessary.Thirdly, appropriate construction details should be taken to avoid reducing of beam bar anchorage capacity.

Abstract:Structural noises induced by urban viaduct box beam basically comes from the vibration responses with low frequency noises, which may affect the surrounding buildings’ security, the common using of highprecision instruments and the living of human beings etc.In order to study the principles of structural noise of railway box beams, the infinite longitudinal stiffened concrete cylindrical shell in air was actively investigated.Aimed at the fluid structure interaction, the characteristics of sound radiation of coupling system were investigated by the wavenumber domain approach and transfer matrix method.And the effects of various parameters on the properties of concrete cylindrical shell, including the position of observation point, the size of the external excitation force, structural damping and the amount of longitudinal ribs, were numerically simulated based on the proposed analytical model.It is found that the increase of longitudinal ribs can effectively reduce the vibration and structural noises of concrete cylindrical shell.The observations would be provided as beneficial guidelines for the noise mitigation of pipeline structures and railway box beams.

Abstract:Based on coulomb’s theory and the study on the shape of the principal stress arching in limiting state soil behind the rigid retaining wall with the rotation about base, the horizontally earth pressure factor and the horizontal friction coefficients were calculated for different friction angle of soil and friction angle between wallsurface and soil to study the vertical stress and shear stress.And the theoretical formulas were obtained for the active earth pressures, the resultant earth pressures and the points of application of resultant earth pressures.The effects of the internal frictional angle of backfill and the frictional angle between the wall back and the backfill on several parameters were investigated, which included the lateral coefficient of earth pressure, the horizontal friction coefficients, the unit earth pressure, the resultant force of earth pressure, the application point of the resultant force and the overturning stability of a retaining wall.And the formula proposed was compared with some experimental observations.And it is found that the results are in good agreement.

Abstract:Relevant national codes usually require the transmitting coefficient method to be employed for the stability analysis of slope reinforcement, in which sliding mass is usually divided into a number of vertical slices.For some support technologies, such as rock bolting and anchor cable, the intersections between the slices and the anchorbar, and the forces mobilized in the reinforcements are different from the assumptions in this method.Thus the transmitting coefficient method confronts some difficulties during practical applications, which would influence the project quality of reinforcements.A new Horizontal Slice Method was proposed based on the overseas relevant literatures to overcome these difficulties in the stability analysis of rock bolting and anchor cable slopes.

Abstract:Shaking table tests were carried out for Minghe River Aqueduct in SouthtoNorth Water Diversion Central Line Project.Based on the data of the tests，dynamic response characteristics were analyzed for two different design alternatives, which were equal length pile foundation and Unequal length pile foundation.The effect was initially estimated on the dynamic response of pile foundation when circle spray reinforcement was used.And woodrubber model box was objectively evaluated in the tests.It is shown that unequal length pile design alternative is more appropriate than equal length pile.Moreover, circle spray reinforcement can improve the behavior of dynamic response of pile foundation and woodrubber model box is rational and feasible.

Abstract:The prediction with RR’s two invariant Model are smaller than the data, while it can catch the trend of linear increase in band angle with increasing mean stress for fixed values of the least compressive stress and a decrease with increasing values of the least compressive stress.Based on the RR’s two invariant Model, with a Lode angle as the third invariant and the more complicated yield condition, true trixial compression test was carried out.And threeinvariant model was proposed in good agreement between real data and predictions.

Abstract:In order to evaluate the aggregates contact characteristics of asphalt mixtures, an effective method of evaluating the aggregates contact characteristics of asphalt mixtures was proposed.The “contact couple” was established as a quantitative index of aggregates contact characteristics and 72 digital images of mixtures’ cut sections were obtained from the rutting test samples of AC20 HMA.Thus a statistical analysis of contact couples was made from the digital images.It is indicated that the contact couples are with normal distribution.Besides, the scale ratio of aggregates above 4.75mm (C>4.75)、the fine index (FI)and the segregation index(SI) were presented as main impact factors of aggregates contact characteristics.And further investigation of the relationship between impact factors and aggregates’ contact characteristics was carried out.It is revealed that the impact factors have good correlation with the contact couples, the interaction of impact factors is the main reason that influenced the aggregates contact characteristics, neither single factor nor dual factors can reflect the samples’ contact numbers exactly.

Abstract:Aiming at the lack of the current determination method for voids in practical engineering applications, in order to accurately quantify the voids beneath cement slab, the determination method was proposed with slab edge  slab center deflection difference and slab corner  slab center deflection difference in the same cement slab for voids.Threedimensional models were set up using the ANSYS finite element method for voids beneath slab corner and slab edge.And the load was simulated with FWD test results.Thereafter, the deflection values were calculated in slab center, slab corner, slab edge under different void depth, void area and load transfer capacity.And the range of deflection diffidence was obtained.With YantaiWeihai expressway, detection data for deflection using Falling Weight Deflectometer were statistically analyzed.And the criteria and correction factors of load transfer capacity were given with simulation and samples analysis.The feasibility of criteria was verified by actual test data.It is found that the simulation values and the test values are in good agreement.The accuracy of void determination by lab edge  slab center deflection difference and slab corner  slab center deflection difference are 88.5% and 84.6%, respectively, which meet the engineering requirements.The voids were determined under the same conditions with the elimination of deflection variability.

Abstract:The threecomponent coefficients of section model of YouCha Bridge were obtained by using two fivecomponent balances.And the threedimensional aerostatic stability of YouCha Bridge was analyzed based on the modified increment and innerouter iteration method implemented in ANSYS.It is indicated that the aerostatic stability of YouCha Bridge with spatial main cables is more excellent compared with those of suspension bridges which have two parallel main cables.A full aeroelastic model with geometrical scale of 1:90.35 was designed and used to experimentally determine the wind velocity inducing aerostatic divergence in smooth wind.And it is found that the critical wind velocity for attendant bridge is higher than the design wind velocity.

Abstract:In order to simplify the calculation of threshold luminance difference, based on threshold luminance difference experiment calculation model of ANSI/IESNA RP800, two simplified calculation models were proposed with constant stimuli experiment and WeberFechner's Law， respectively.Negative contrast correction coefficient, identification time correction coefficient and age correction coefficient were obtained.A road lighting visibility was calculated with these two models and the model of RP800 as a case study.It is found that the visibility values calculated from these three models are in good agreement.

Abstract:Based on the field survey and the analysis of typical civil residences, a experimental model of artificial lighting luminous environment for residential living rooms was established, and psychological evaluation indexes including spaciousness、pleasantness、privacy、clarity、order、relaxation、subjective impression of colour temperature and glare were made.Furthermore, the property matrix was set up after sampling survey and evaluation of lighting experts.With the method of mean square deviation, a comprehensive evaluation function was proposed for living room with verification by experts grading.It is found that the comprehensive evaluation function matches experts grading very well.For the average illumination of about 150lx at the horizontal plane of 0.75m, people would get the higher psychological satisfaction when the uniformity of illumination is 0.4 to 0.5 in artificial lighting luminous environment, while the lower psychological satisfaction would get when the uniformity of illumination is greater than 0.6.

Abstract:In order to improve utilization of cold and heat source from river, turbulence theory and entropy generation theory were adopted to analyze the effect of fouling on convective heat transfer performance in small diameter tube of constant wall temperature.It is found that the entropy generation caused by conduction of fouling plays a more important role in total entropy generation of heat transfer process through a duct than that in cveast rate of caused by temperature difference.The entropy generation caused by viscous flow is more than the entropy generation caused by temperature difference in flow with bigger Reynolds and small radius.The increase rate of entropy generation monotonically increase with Reynolds and the generation process of fouling resistance.Thereafter, the effect of fouling resistance on the heat transfer performance of water source heat pump heat exchanger should be paid more attention, when river water are used as the cold and heat source of heat pump.

Abstract:There exists the shortage of holistic building energy efficiency assessment models which consider the uncertain or incomplete information, whereas most previous studies focus on building energy consumption via computer simulation.To tackle the above deficiency, an energy assessment and labeling model of residential buildings was proposed based on the theory of evidence and the national and local building erergy efficlency standards.A method has been achieved by applying the model in residential buildings in hot summer and cold winter area.A computer software toolkit was developed based on the above method.To demonstrated and validated the proposed method, a case study was addressed with the software toolkit.Meanwhile, the same project was assessed with the ‘Assessment standard for energy efficient buildings’.It is found that the two methods are in good agreement and the proposed method can deal with the uncertain information.

Abstract:PCRDGGE and realtime PCR technologies were applied to analyze the relationship between operation efficiency and microbial community structure of the Sequence Batch Biofilm Reactor(SBBR) autotrophic nitrogen removal process.The reactor was possessed of a high nitrogen removal efficiency.And the similarity of microbial community structure between active sludge and biofilm samples was 58.3%. The features of DO distributing on active sludge and biofilm made an appropriate condition for different bacteria.Ammonium oxidation bacteria and anammox were the preponderant bacterium in reactor.And their cometabolisms made TN removal rate reach to 90% and 80%,respectively.The reactor worked under a low efficiency with low concentration of biofilm.It is found that there is no much difference between biofilm and active sludge samples on the microbial community structure.The similarity reached to 100% and the variety of dominant bacteria was poor.Nitrite oxidation bacteria (NOB) were not “washed out” during the setup time that NO3- was accumulated in this reactor.TN removal rate was only about 20% to 30%.

Abstract:A SBR inoculated with conventional activated sludge was employed to cultivate aerobic granular sludge.Under the selective pressure of settling time, the formation of nitrifying granules enriched with the ammonia oxidizing bacteria (AOB) was achieved by increasing the nitrogen loading rate (NLR).The nitrifying granule was shaped like a sphere or a ellipsoid with an equivalent diameter of approximate 1.1 mm, an average settling velocity of 1.9 cm·s-1and the sludge volume index of 18.2～31.4 mL·g-1.As the aerobic granular system was operated stably, the NLR reached a value of 0.045 5 kgNH4+N· (kg MLSS·d)-1 with ammonia removal efficiency above 95% and nitrite accumulation ratio in the range of 80%～90%.The NLR was 4.55 times higher than that of the startup period.The enrichment of the nitrifying bacteria was quantified by FISH analysis which indicated that AOB was 14.9% of the total bacteria and nitrite oxidizing bacteria (NOB) was 0.89%.It is concluded that the associated inhibition of FA at the start of the reaction and FNA at the end of the reaction would be the key factors to start up and maintain the stable nitritation.

Abstract:The harm impact evaluation was studied for pollution accident happened in urban crude water system characterized of fetching crude water from reservoir through channel.The relevant direct and indirect factors to harm impact of crude water pollution accident were analyzed.Furthermore, the attribute reduction method in rough set theory was applied to eliminate the redundancy of indirect factors.Integrating the direct and indirect factors effects, an emergent evaluation model for the HarmImpact was established with the similarity analysis by vague sets theory.Taking crude water system in Chengdu as a case study, a designed nitrobenzene pollution accident was simulated in different workingconditions.Moreover, the Harm Impact extent of the accident was calculated with the proposed model.The sensitivity analysis indicates that the proposed model is reasonable and valid in the emergent evaluation for the pollution accident happened in the urban crude water system.

Abstract:The goal of AHPGrey Relational Analysis model is to solve problems during selecting the best waterworks sludge treatment process.And grey Relational Analysis is to confirm the compactness between the ideal process and candidate process.Moreover, weighting system was determined by the threemark matrix and consistency analysis of judgment matrix for traditional AHP was improved by the optimum transfer matrix.Base on these theories, AHPGRA model was established.A case study was addressed with the selection of waterworks sludge treatment process in Chongqing.It is found that this model is legitimate and credible.

Abstract:The BAF for wastewater treatment loaded with new ceramic fillers was investigwed in comparison with the BAF loaded with biogenic ceramisite agitator.The feasibility and features of the new ceramic fillers had been analyzed by comparing the two fillers and the operational parameters had been analyzed and determined at the same time.It is shown are that when the average influent CODcr is 135.6 mg/L, NH4+-N 42.1 mg/L and TP 0.69 mg/L, the removal efficiencies of The BAF loaded with new ceramic fillers and ceramisite agitator are 81.2%, 99.8%, 68.1% and 80.8%, 99.5%, 66.7% respectively at the condition of the HRT=1.5 h.New ceramic fillers required less water to backwash and had better effect than biogenic ceramisite agitator at the same condition, what is more, the running costs of the BAF loaded with new ceramic fillers were less than that of the BAF loaded with ceramisite agitator.

Abstract:In order to discuss the reaueing theory of simultaneous nitrification and denitrification (SND), with the sequence batch reactor (SBR), the dissolved oxygen (DO) and the floc size distribution were investigated for sewage wastewater.It is found that the SND can be attained in SBR process by nitrogen mass balance calculation with low DO (mean value 0.5 mg/L0.8 mg/L).Around 23.11% nitrogen in total nitrogen is removed by SND.The ratio of nitrate formation and ammonia decay is at 0.454 with the DO concentration at 0.5 mg/L.Meanwhile, the velocity of nitrification and denitrification is equal.And the SND couldn’t occur when the ratio of nitrate formation and ammonia decay is equal with DO at 4.296 mg/L.The mean floc size distribution of sludge is at the range of 5.02 μm ~6 μm, that is, the SND is not the results of “micro environment action” when SND occurs.

Abstract:In order to solve the problems that the exiting technologies do not adapt to the deterioration of the water quality in the water plant, the ultrafiltration was used to treat water respectively from ozonebiological activated carbon pool (process 1), sand filtration pool (process 2) and sedimentation tank (process 3) in the region of river network of southern China.It is found that the average DOC removal rate were 33.08%, 23.60%, and 18.55%, and the average alga removal are 98.71%, 97.84%, and 98.13% in the process 1, process2 and process3, respectively.The turbidity of the effluent is lower than 0.1 NTU, and the particles with their size bigger than 2 μm were lower than 20 per milliliter in all the three process.The transmembrane pressure increased by 6.59% and the water production rate of the UF membrane was 98.02% during 45 days pilot experiment in the process 1.When 0.65mg/L chlorine was added before ultrafiltration membrane, the transmembrane pressure was recovered effectively after hydraulic flush.And the transmembrane pressure increased by 2.91% and the water production rate of the UF membrane was 97.63% during 10 days pilot experiment in the process 2.The transmembrane pressure increased by 13.52% and the water production rate of the UF membrane was 97.01% during 20 days pilot experiment in the process 3.