Abstract:

Abstract:To analyze mechanical behavior of Q460 highstrength singleangle steel struts with an eccentric load at one end in transmission towers, experimental analysis and theoretical calculation were carried out to study the overall stability and local buckling of members. Spherical hinge bearing and double knifeedge bearing were applied at axial end of specimens. Influence of some factors on bearing capacity of compression members with eccentricities at both ends was analyzed, such as the end supporting conditions and residual stresses. It was shown that whether spherical hinge bearing or double knifeedge bearing was used at axial end, the mechanical behavior can be accurately presented and the residual stresses affected the ultimate loadcarrying capacity by about 5％ or less. Compared with different methods, such as experiment method、finite element method, method in the Guide for American Design of Latticed Steel Transmission Structure（ASCE101997）and method in Chinese Technical Regulation of Design for Tower and Pole Structure of Overhead Transmission Line (DL/T51542002), it was found that the calculated strength of highstrength steel member by standard calculation method in DL/T51542000 was overconservative. According to the research results, the revised formulas of ASCE were proposed with dividing actual material strength by the resistance coefficient of rR=1.111. Therefore, the experimental results can provide reference for designing highstrength Q460 singleangle steel members compressed eccentrically at one end.

Abstract:Based on maintaining the accuracy of existing models for circular specimens, revised models were proposed for predicting strength and ultimate strain of concrete columns confined with FRP with considering the effectiveness of confinement by crosssection. An evaluation of existing strength and ultimate strain models of concrete columns confined with FRP was presented with extensive collection of experimental data. It was shown that the prediction of strength was more accurate than that of ultimate strain, among which the prediction of Gampione’s strength model and Lorenzis’s ultimate strain model were more accurate for all specimens and circular specimens, respectively. The comparison with experimental results and existing models showed that the proposed models were more accurate, simpler and more convenient. The proposed models can be used for the prediction of strength and ductility in practical engineering.

Abstract:In order to study torsion behavior of steelencased concrete composite beams, experiments were carried out with eight specimens. The destruction shape, working mechanism and the crack development and distribution were analyzed under pure torsion and combine torsion conditions. And also the relationships were investigated between torque and torsion ratio, load and strain, bending moment and deflection and loadcrack. On the basis of elasticity plastic theory, the formulas of cracking torsion were presented for pure torsion and combined torsion of combined beam. And with spatial truss model of variable angle, formulas for ultimate torsion strength of pure torsion and combined torsion were put forward. The predicted results were in good agreement with measured ones. The proposed formulas provided basis for evaluating safety and stability of the structural.

Abstract:A new method was presented which was based on finite element method to predict the fatigue life of tower crane's steel structure. With the method, the finite element model of tower crane was developed and the static stress was calculated. And then time history was defined. It was found that there were two main types of fatigue loads acting on tower crane, which were the amplitude load and the impact load. For the amplitude load, a method with field observation and statistical method was proposed and it was found that the frequency of the trolleyjib slipping the stride on the orbit and the beam's coordinate showed statistically normal distributions. And time history of amplitude load was calculated with one day as a cycle. For impact load, taking transient response method, the relationship between internal stress and time was established for main working conditions and the time history was obtained. Taking the static stress of tower crane, time course of amplitude load and time history of impact load as inputs, the fatigue life of steel structure was obtained with the software of MSC.FATIGUE. 

Abstract:The first degree second order moment method (JC method) recommended in Unified Standard for Reliability Design of Building Structures (GB500682001) was applied to analyze the reliability of steelreinforced highstrength concrete filled steel tubular slender columns. Several performances were studies, which were the influences of different load combinations, specific values of loads, strength grades of concrete, thickness of steel tube, area of crosssection of structural steel, steel yield strength and slenderness ratio on the reliability of the composite column. It was found that, when the slenderness ratios were within common range, the reliability indexes of the proposed formulae satisfied the demand of GB500682001 for plastic material on the whole. And it was concluded that the reliability index varied with the load combination and specific value of loads. The reliability index increased with the increase of concrete strength grade and decreased with the increase of steel tube thickness. Furthermore, steel yield strength and slenderness ratio had different influences on the reliability indexes.

Abstract:In order to study the compressive failure characteristics of layered rock mass and build the corresponding theoretical model, the fast lagrangian method was adopted to address numerical simulation of the layered rock mass under triaxial compression. The relationship between compressive strength and inclination of structure plane was analyzed, and a theoretical model was proposed to describe their relationship. The test data from the foreign references were described by the theoretical model and the relationship between loading velocity and the compressive strength was analyzed. It was shown that, the fitting model can well describe the strength characteristics of stratified rock mass, which was validated by the numerical test and laboratory test. And the compressive strength of rock mass increased linearly with the increase of loading velocity. 

Abstract:Foundation pits with dualistic structure of soil stratum and underlying rock stratum were commonly across Qingdao area. Aiming at the characteristics of “endsuspended pile”, numerical simulation with Finite Element Method(FEM) and analysis was carried out to study the design methods and other influencing factors, such as stability, depth of the pile body, axial stress of anchor and width of reserved rock shoulder. It was shown that traditional design methods were applicable for the upper soil stratum, with the excavation stability guaranteed. The increase in embedded depth of pile body or axial stress of anchor led to effective control over excavation stability and deformation of the underlying rock stratum. And the axial stress was the main controlling factor, hence intense monitoring should be carried out on the stress during the course of construction. The larger the width of the rock shoulder was, the smaller the displacement of piles would be. When the width exceeded a certain value, its influences on the displacement and bending moment of piles tended to be insignificant.

Abstract:The elastoplastic constitutive relation of high compressibility clay in Wuhan was investigated. On the basis of the framework of Duncan E~v model, an elastoplastic constitutive model was derived by fitting the data of triaxial compression tests under CTC stress path on isotropic consolidation condition. With the average slope of unloadreload curves as unload modulus, the loadingunloading function was introduced as the loadingunloading criterion. Moreover, the comparison was made among the stressstrain relation curve simulated by the proposed model and those with Duncan model and test curve. It was shown that the proposed model was more reasonable, which can reflect the stressstrain relation of normally consolidated soils under CTC path. Especially, the model can reflect the strain strengthening effect. The maximum relative error was no more than 5%.

Abstract:For the large span and flat, together with the interaction effect of construction and disturbance of surrounding rock, the mechanical of large span and flat multiarch tunnel is very complicated, and the timespace effect is different from that of twolane multiarch tunnel or separated tunnel. Adopting the “CTSSSRH”, the 3D dynamic process of the tunnel construction was simulated. Analyzing the rule of surrounding rock displacement and stress with excavation, the timespace effect of large span and flat multiarch tunnel was proposed.

Abstract:Based on the stochastic medium theory, influence on the surrounding rock and soil by tunnel excavation was studied. formula for predicting movement and deformation of rock and soil mass caused by tunnelling were deduced. And especially for the tunnel with circular arch section, half analytic solution for this problem was put forward. Furthermore, a program was developed to compute the movement and deformation of the rock and soil mass resulted from excavation. The deformation failure criterion of stochastic medium for estimating the surroundings safety was provided and was applied in an engineering example, which proved that the results of the research were reasonable and significant for the tunnel safety construction.

Abstract:Utilizing the selfmade unitbody model test apparatus, the deformation laws of backfill grouting were studied under different grouting pressures, different soil conditions and different ground water pressures. It was shown that high grout pressures can accelerate the consolidation rate of grout drainage and increase final deformation amount. And soil permeability coefficient was an important factor to grout deformation. The ground water pressure was more important for sand soil while the grout pressure was for clay soil. The proposed apparatus can truly reflect stress status of grout injected to tail void. And grout deformation properties were helpful to clarify the stratum stress release and stratum deformation of backfill grouting. 

Abstract:Taking a complexshaped highrise building as a case, the wind tunnel test with rigid model was carried out for wind load study. Meanwhile, with Fluent 6.1 software, the CFD numerical simulation had been performed with the RSM and the Nonequilibrium Wall Functions. It was found that the results of the two methods were in good agreement. There were mainly positive pressures on the windward surface and negative pressures on the roof, the leeward surface and the side. Especially, negative pressure was higher in the leeward region at the building corner. And at the wind angle of 180°, the wind speed amplification effect was remarkable which was similar to those of canyons.

Abstract:The control effects of a connected tall building structure with viscous damper in several respects were studied, such as internal force, deformation, acceleration and energy under dynamic wind load. Firstly, wind pressure timehistory data were obtained from the windtunnel test of the structure model, and then a wind load processing program WINDHIST V2.0 based on wind tunnel test was developed, by which wind pressure data processed and inputted into Finite Element Method(FEM) program. Thus windinduced vibration timehistory could be analysed under various working conditions. It was shown that both the internal force and deformation of the connected structure with viscous damper can be decreased, while the effect of the former was more obvious than the latter. The acceleration at the top of the connected structure caused by dynamic response of fluctuating wind can be controlled effectively by viscous damper.

Abstract:The temperature effect was of crucial importance to estimate structural state of existing PC cablestayed bridges. Taking Yonghe Bridge in Tianjin as a case, the influence of temperature effect, including temperature change of whole bridge, difference in temperature of cable and main girder, temperature Gradient in the transverse section of main girder, and temperature gradient in the transverse section of tower, was analyzed on geometry of bridge deck, inclined displacement at the top of tower and cable force. Based on observation data of Yonghe Bridge during the First and Second maintenance, effectiveness of temperature effect analysis based on the present bride code in China was verified. And then a modifying method of temperature effect in structural state estimation was proposed. It was shown that the temperature change of whole bridge and the difference in temperature of cable and main girder were the main factors to inclined displacement at the top of tower, and the difference in temperature of cable and main girder was the main factor to the deflection of main girder. Although a small error between measured and theoretical results caused by the rigidity deterioration of old bridge, the temperature effect analysis based on the present bride code in China could be feasible in structural state estimation of existing PC cablestayed bridges and provided reference for maintenance and construction control.

Abstract:Stress, due to shrinkage characteristic difference resulting from different concrete age at typical interface parts in long span rigidframe bridges, was analyzed based on Chinese and American codes. Reasons for large discrepancy between results under the two codes were also discussed. It was shown that shrinkage stress level calculated under AASHTO was more reasonable than that under Chinese code (JTGD 622004) for concrete members with large thickness. Concrete at interface parts was easy to crack when casting time interval was long. According to JTGD 622004, stress at interfaces was always small under different casting time intervals, while stress at position with mutation section was more significant. It was necessary to set an upper limit to theoretical thickness in JTGD 622004, and 300 mm was recommended. Finally, some design and construction approaches were put forward.

Abstract:In order to realize energy saving of urban nightscape luminance, power consumption was studied with the change of urban luminance. Based on energy consumption indicator(LPD) of 8.9 W/m2, it was calculated that about 0.84W more energy consumption would be for 1 cd/m2 increase of luminance. The effect of 1 to 2 cd/m2 increase was hard to distinguish for human’s visual function under urban nightscape, while the energy consumption was great. Under the same lighting condition, the reflecting characteristics of building surface materials could affect directly the luminance of nightscape. With the study of the reflecting characteristics of different building surface materials, an illumination calculation model for building was proposed based on the formulation of CIE.

Abstract:Hydroxypropylmethyl cellulose(HPMC), Sodium Chloride and pure water were adopted to develop green cellulose ethers thermotropic materials. And thermally induced switching temperature, visible and solar direct transmittance were measured under different mixing proportion. For energy consumption, DeSTh was used to study the energy efficient effect of thermotropic doubleglazing windows with different mixing proportion. It was shown that the optimum mixing proportion of hydroxypropylmethyl cellulose(HPMC), Sodium Chloride and pure water was 2:15:100 by mass. And thermotropic doubleglazing window can reduce energy consumption by 3% and 8%, respectively, when compared with LowE doubleglazed window and common doubleglazed window in hot summer and cold winter zone.

Abstract:The field test and questionnaire survey were carried out in the departure lounge at the railway stations in Changsha and Shanghai which were typical cities in hotsummer and coldwinter zone. Thermal sense vote (TSV), thermal neutral temperature and acceptable temperature range were studied. It was shown that the response of passengers to thermal environment was different. The thermal neutral temperature was 27 ℃ and acceptable temperature range was 23.8~30.2 ℃.The passengers' TSV did not keep at the initial value. Instead, it increased with the increase of waiting time and the growing rate depended on the difference of indooroutdoor temperature.

Abstract:Based on monitoring data of water quality and river runoff from 2007 to 2008, the dynamics of TN and TP transported into the backwater region of the Linjiang River were investigated and fluxes of TN and TP were also estimated. It was shown that the dynamic changes of TN and TP were significant. The concentration of TP in rainy seasons was higher than that in dry seasons, while the cases for TN was contrary. The fluxes of TN and TP were significantly higher in rainy seasons than those in dry seasons. On average, there were about 4 142 t TN and 455 t TP transported into the backwater region of the Linjiang River every year. And TN flux decreased by 32.7% from 2007 to 2008, while TP flux increased by 34.3%, which was in agreement with the interannual variation of the concentrations of TN and TP. TN flux was primarily influenced by river runoff, whereas TP flux was affected by both concentration and runoff. Further analyses indicated that TN was mainly caused by point source pollutants(dominated by NH3N, and then DON). On the contrary, TP was mainly caused by plane source pollutants(dominated by PO34P). It was also indicated that it was critical to control the point source pollution in the basin to promote the water quality of the backwater region of the Linjiang River.

Abstract:The influences of dissolved oxygen (DO) on the removal process of nitrogen and phosphorous in a sludge reduction system had been studied by controlling aeration amounts. It was found that under the conditions of low doses of 2,4,5trichlorophenol (TCP), endogenous sour values of activated sludge increased with the extension of low DO state duration in SBR system and the decrease of cyclic average DO, which led to a low DO environment favored the formation of simultaneous nitrification and denitrification(SND).TCP concentration was recommended as 2mg / L and cyclic average DO value in SBR system was kept at 2mg / L based on the impacts of TCP concentration on sludge reduction, removal of nitrogen and phosphorous and sludge performance. Compared with the control system, aeration amounts increased by 23% and the discharge of excess sludge decreased by 34.6%. The water quality in effluents was equivalent in the aeration sludge reduction system with 2mg/LTCP, which met the discharge standards. Therefore, it was indicated that the removal of nitrogen and phosphorous and sludge reduction can obtain excellent performance in TCP system under low DO state with removing Phosphrousrich sewage.

Abstract:Kinetics of phosphates removal by Municipal Solid Waste Incineration(MSWI) fly ash were investigated with the tests of EDS, XRF and TEM. It was shown that 95% of phosphates was removed by MSWI fly ash in 30min under 303 K. The process was heat intaking process whereas the heat amount required was small. Heavy metals were stabilized during the process and no heavy metals were detected in solution after reaction. Chemical precipitation was the main way of phosphates removal. Ca、Fe、Zn etc. can provide cations for phosphates removal reaction. The macro kinetics of phosphates removal by MSWI fly ash can be represented by the model of sphere internal diffusion control. And internal diffusion process of PO34 and soluble products were the controlling step. The relation between reaction rate of phosphate (X) and reaction time (t) can be represented as 13(1X)2/3+2X=kt; the apparent activation energy was about 10.06kJ / mol .

Abstract:A technology of wastewater treatmentcompound artificial wetland was developed in connection with the characteristics of water pollution in small cities and towns in China. That compound system was composed of vertical baffled wetland filter under anaerobic conditions and lateral subsurface flow wetland bed under facultative conditions. By setting up the inner backflow system, the nature reoxygenation area and the gravel filler with a particle size of 8~30 mm, the dissolved oxygen(DO) division in the system was achieved with the optimization of the flow pattern and the increase of treatment efficiency. The application results indicated that, under the conditions that the water flow rate was 300～450 m3/d, COD, NH+4N and TP concentration of the inffluent were 60~250 mg/L, 4.5~23 mg/L and 1.5~8 mg/L respectively. And these values of the effluent were 20~30 mg/L, 2~4 mg/L and 0.3~0.5 mg/L respectively at low temperature and could fall below 30 mg/L, 4 mg/L and 0.43 mg/L at normal temperature.

Abstract:The influence of influent nitrate on phosphorus removal efficiency of phosphate reduction systems under anoxic and aerobic condition was studied by changing the concentration of influent nitrate. It was shown that nitrate had significant influence on phosphorus removal efficiency of phosphate reduction system under anoxic and aerobic condition. When influent nitrate concentration was between 105 mg/L and 160 mg/L, it was favorable to anoxic phosphate reduction. However, influent nitrate had a remarkable inhibition on aerobic phosphate reduction, and there was a significant negative correlation between them (R2=0.982 7). The difference on phosphorus removal efficiency was mainly due to different influence of nitrate on microenvironment structure under various oxygen environments. Moreover, different concentrations of influent nitrate also affected the pH value in the reactor, which can affect phosphate reduction process. It was found that slight alkaline (pH around 8) was favorable for phosphate reduction under anoxic and aerobic condition.

Abstract:Two types of wetting lowcalcium fly ash were made for studying the performance under different storage time (1 to 60 months). The surface morphology, granule size distribution of the wetting fly ashes and their properties as supplementary cementitious materials in concrete were investigated. Although the granule size increased and there appeared considerable erosion on the surface, the surface morphology of wetting fly ash kept mostly unchangeable. The water reducing effect resulted from mineral properties of fly ash decreased much due to wetting. Compared with a parallel concrete with dry fly ash, slump of concretes with fly ash of 20~40% wetting for 3 months decreased by 20~40 mm while bleeding and permeability and carbonation had no change. The compressive strength of concrete in 28 day and 60 days with fly ash of 30% wetting for 3 months decreased by 5.8% and 3.7% respectively. However, the specific compressive strength of concrete in 56 days with fly ash of 20% wetting for 36 months still reached at 85% and there was no visible strength discrepancy of fly ash concrete wetting for 3 and 5 years. It was concluded that a wetting lowcalcium fly ash could be used as supplementary cementitious material in some important concretes. 

Abstract:Microstructure and macroperformance of Ultra Low Ion Permeability Cementitious Materials (ULIPCM) were investigated by Microhardness, MIP and SEMEDXA. It was shown that the compressive strength of ULIPCM was more than 80 MPa, flexural strength was more than 11.0 MPa, and elastic modulus was in the range of 38.0 to 42.0 GPa at the age of 28 days; chloride diffusion coefficient was lower than 0.8×10－13m2·s－1, conductive charge for 6 hours was lower than 300 coulombs; sulfate attack resistance was good; shrinkage at the age of 28 days was lower than 400×10－6. Compared with ordinary concrete with which thickness of interfacial transition zone is 60 to 100 μm, the thickness of interfacial transition zone of ULIPCM was lower than 30 μm. Penetration paths of corrosive medium were effectively interrupted in ULIPCM. And pore structure parameters, such as porosity and the most probable pore radius of ULIPCM, were also obviously optimized in ULIPCM. Besides, few CH crystals were in the ULIPCM aggregate and the interfacial transition zone of ULIPCM. And the orientation of CH crystals was poor.