Abstract:The wind pressure time history records of the annular cantilever roof were obtained by the synchronous wind tunnel test on a rigid model of a stadium. Considering the influence of the vortex shedding, the correlation coefficient and coherence function of along wind and cross wind points were analyzed to get the characteristics of the external fluctuating pressure correlation of the stadium's cantilever roof. The coherence function curves were fitted and the related coherence function was presented. Compared with the classical coherence function models, the present coherence function has the same form and a higher fitting accuracy for the cantilever roof.

Abstract:The distribution of the axial stress and shear stress on the anchorage segment and the formulation for calculating the anchorage length were derived based on the stress analysis of the anchorage segment of compression anchor. And the effects of parameters, including the elastic modulus, poisson ratio, cohesion, and internal fiction angle of rock mass, on the anchorage length were studied. The results show that the anchorage length decreases with the increase of the elastic modulus, cohesion and internal friction angle of rock mass; and the anchorage length increases linearly but limited with increasing of poisson ratio of rock mass; and it also increases with increasing load.

Abstract:The space distribution characteristics of equilibrium moisture of non saturated clay subgrade were surveyed along the road cross section by the in situ and laboratory tests. Based on the basic theory of unsaturated soil mechanics, matric suctions of soil samples with different kinds of moisture condition were determined and the soil water characteristic curve model was calibrated to reflect a single valued function relationship between water content and matric suction of clay soils. Combining the above results, an estimation method of the equilibrium moisture of the unsaturated clay subgrade outside the affected zone of atmospheric precipitation/evaporation was established. The results show that the atmospheric precipitation/evaporation has significant effect on moisture condition of the subgrade soil located in the upper part of the subgrade near the central reserve and hard shoulders. However, equilibrium moisture of subgrade soil outside the affected zone of atmospheric precipitation/evaporation is mainly controlled by the impact of the groundwater table. Fredlund & Xing model can be used to characterize the relationship between the unsaturated clay soil moisture and matric suction, and the fitting results of model parameters have high reliability. A consistency between the predictive results and the experimental data shows the presented model is accurate and credible.

Abstract:The mechanism and lateral bearing capacity of reinforcement concrete (RC) frame with dry stack in filled panel (DSIP) were investigated using quasi static experiments and finite element models. According to the parallel model and equivalent strut model, the lateral bearing capacity of RC frame and DSIP were researched separately. Results show that: 1) The plain stress element and interface element are applicable in finite element (FE) model analysis. According to the FE model, the failure of RC frame with DSIP is caused by the damage of frame; 2) Lateral bearing capacity of DSIP is mainly from the friction between bricks in the panel, which can be divided into 3 stages: constant stage, increasing stage and ultimate stage; 3) Equations for lateral bearing capacity of DSIP were proposed and verified by FE model results.

Abstract:The settling curve of single pile with grain spillage under the effect of vertical static load was analyzed. The curve was divided into 3 parts: elastic line phase at the beginning, grain spillage tamping phase and elasticity breaking phase in the end, and the settling characteristics in three phases were described mathematically and the mathematical expression was concluded as well. Based on the calculation of the parameter with the optimizing calculation method, the parameter of “theoretical limit load” computing formula that satisfies the definition of limit load was presented. Comparing with the experimental result of the indoor single pile modeling, it is found that this parameter computing method is practical, which provides another method to predict the limit load and settlement of the single pile with grain spillage.

Abstract:In order to improve the understanding of the mechanism of h type anti slide pile to reinforce the slope, this type of anti slide pile with different anchorage depth and distance between fore pile and back pile was investigated through model test by specially designed experimental apparatus. The test results indicate that the distribution of resistence and thrust acting on fore pile is triangular, and the resistence acting on back pile is rectangular. For the landslide thrust acting on back pile, there are three types of distribution: parabolic, parabolic with upper center of gravity and rectangular. Therefore, when the calculation pattern for the part of h type pile above the potential slip surface is defined, the distribution of resistence and thrust acting on fore pile can be fixed as triangular, and the resistence acting on back pile can be fixed as rectangular. Whilst the distribution of landslide thrust acting on back pile should consider the influence of property of soil, anchorage depth and the distance between fore pile and back pile. Some conclusions drawn from this test can provide useful reference for the design of h type anti slide pile.

Abstract:In order to investigate the flexural behavior of concrete beams reinforced with high strength hot rolled bars of fine grains, static bending test on four rectangle cross section HRBF400, HRBF500 RC beams was conducted. The results show that the experimental maximum crack width under short term load meets the requirement of current code while calculated value does not meet; mid span deflection of RC beams with HRBF400 under short term load still meets the requirement of current code while RC beams with HRBF500 does not meet. Bearing capacity calculating formula under conditions of crack/deflection control was proposed and conception of component's bearing capacity utilization coefficient (BCUC) was put forward. The influences of reinforcement strength, reinforcement diameter, concrete grade, reinforcement ratio, concrete cover thickness and high span ratio on BCUC were analyzed. Within the range of economic reinforcement ratio, ductility of HRBF RC beams meets the requirement. Energy dissipation capacity of HRBF RC beams is similar to that of normal RC beams at low reinforcement ratio but it decreases faster than normal RC beams with the increasing of reinforcement ratio. Energy dissipation capacity of HRBF RC beams is higher than that of normal RC concrete beams in elastic stage and it enhances with the increasing of reinforcement ratio.

Abstract:Based on the mechanism of steel slit wall, a simplified elasto plastic analytical model which allows for nonlinear dynamic and static analysis was proposed. The parameters of simplified model related to configuration and nonlinear behavior were defined. In order to validate the simplified model, the pushover analysis of steel slit wall and a frame with steel slit wall were conducted. The results show that the load displacement curves obtained from simplified models, experiments and FEM are similar. The proposed model can fully represent the mechanism of steel slit wall, and it can correctly predict the internal forces and deformations of each member in the model.

Abstract:In order to analyze the seismic behavior of widened beam flange joints, 16 specimens were derived from finite element models base on experiments. The effects of some parameters, such as the increased width and length, on ultimate load and ductility performance of joints were further discussed with ANSYS finite element method. According to specimen failure phenomenon of both experiment and finite element method, the weak link of the joints was found and the cracking possibility was evaluated. A theoretical analysis of the fracture mechanism of widened beam flange connection was conducted. In addition, design method of widened beam flange parameters was introduced, which will offer valuable information and reference for seismic design in steel frame joints.

Abstract:Based on the simplified elastoplastic constitutive model of soil, the calculation method for the laterally loaded single pile with large deflection was submitted. The coefficient of subgrade reaction was presumed to increase linearly with depth, which simulates the soil resistance close to ground well. The relevant program was then developed using FORTRAN language. The examples show that (1)the displacement and bending moment increase nonlinearly when the lateral load and the moment load increase. (2)The pile displacement decreases with depth. (3)The pile displacement at the point which is over ten times pile diameter from ground is so small that can be neglected. (4)The pile head condition is the key factor, which influences the distributions of pile responses along depth. (5)By improving the mechanical properties of soil around pile, the maximum lateral displacement and bending moment can be decreased efficiently. The calculation results are in good agreement with the field test results and are better than those obtained using the pre existing solutions, which shows the presented solutions are reliable.

Abstract:The heat conduction characteristic of glass curtain wall was investigated. Based on one dimensional steady heat conduction theory, the numerical calculation model of glass system thermal transmittance was set up by using insulating glass as an example. Based on two dimensional steady heat conduction theory and finite element method, both the thermal transfer matrix and temperature load array of 3 DOFs triangular element were derived. Then the revised formulas about the heat transfer matrix and temperature load array under the boundary conditions of constant heat flux, heat convective, radiation and coupled of them were also derived. Then the numerical calculation models of glass curtain wall frame and linear thermal transmittance were set up. The program TJCW based on the Visual C++ and ObjectARX was developed for calculating the thermal transmittance of glass curtain wall and was validated by contrast with the results calculated by thermal software LBNL. Finally, TJCW program was used to calculate and check the thermal transmittance of glass curtain wall in a practical project. The results indicate that the thermal transmittance of glass curtain wall can be calculated correctly by adopting the presented model, and the program based on this model can be used in energy conservation calculation and analysis in the actual projects.

Abstract:Based on the characteristics of spatial structure of residential units, the law of indoor hot smoke flow was investigated by experimental research on a platform model with multiple floors and rooms in a residential building. Three factors exerting influence on hot smoke flow in residential construction were mainly analyzed, including the relationship between the height of space and the area of single room, the size of doorway opening, and the hub space. Based on basic concepts of thermodynamics and fluid mechanics, the geometric relational model of the height of space and the area of single room impacted on filling speed of hot smoke in room was presented by conservation of mass. Moreover, under the influence of hot smoke flow, the formula of doorway opening size was developed by conservation of momentum. The results show that the fire safety of residential building should take full account of the impact of spatial structural. The indoor temperature distribution and hot smoke flow path will be controlled effectively by the design of single room size and room connectivity.

Abstract:By adopting fluid calculation software to establish three dimensional reservoir model and simulating reservoir's natural temperature on design day, the measured temperature was used to correct and treated as the initial condition. According to the annual hourly calculation load of villa cluster, dynamic water temperature and flow were used as boundary conditions. Inputted water surface heat transfer conditions were identified by user defined function based on the data of typical meteorological year. For the distributed drainage combining the discharge network and rainwater pipe network and traditional integrated drainage of reservoir water source heat pump system, dynamic numerical simulation of the water temperature field was conducted. The results show that water's temperature rises 0.33℃ weekly when integrated drainage is adopted and the temperature rises 0.16℃ when distributed drainage is adopted. There is obvious heat accumulation phenomenon when continuous drainage in narrow area works. The simulation of intake water temperature shows that below perennial water level 4.6m depth, the intake water temperature is between 27~23.5℃ from July to October, in which the heat pump system operates efficiently.

Abstract:Solar heating system is a promising sustainable energy source for buildings. Simulation models using EnergyPlus and TRNSYS were used to optimize the solar heating building enclose thermal insulation. The sensitive analysis of active solar heating system design parameters and energy consumption was conducted to study the influence of building envelope thermal performance on the active solar heating system. The two object functions, investing cost and lift time cost, were used to optimize the building envelope insulation. The results show that not only the energy consumption can be reduced by increasing the building envelope thermal performance, but also can minimize the investing cost.

Abstract:Based on an actual ground source heat pump system in hot summer and cold winter area, the system operation parameters were tested for 6 years under the state of using cooling tower for cooling in summer but the ground heat exchanger and fire pool for heating in winter. A three dimensional (3D) tube group model was established, and the thermal balance analysis and calculation of the ground temperature distribution around the ground heat exchanger were conducted by the numerical calculation. According to the comparison between the test data and the theoretical results, the influencing factors of the ground adjustment ability were obtained.

Abstract:Based on the existing experiment, the heat flux characteristics of green roof in passive indoor thermal environment and thermal parameter suitable for evaluation of the thermal performance of green roof were analyzed. It is found that there is indoor critical temperature in acceptable indoor thermal environment range for green roof, in which there is no heat transfer from roof. Through the correlation analysis of internal surface heat flux of roof and the temperature difference between indoor and outdoor, it is shown that the indoor critical temperature is 1.5℃ lower than air temperature outside for green roof.

Abstract:A 448 person time field survey of thermal comfort was conducted in rural houses in east Guangdong in 2011-2012, during which the environmental parameters including air tempreture, relative humidity, globe tempreture and air velocity were recorded and the thermal sensation, acceptability and preference of inhabitants were collected. Clothing insulation was found to be a quadratic function of indoor ET*. Thermal sensation was found to be in good linear relationship with air /operation /new effective temperatures, based on which thermal sensation models were established for local inhabitants in rural area. The model shows that the neutral temperature is 26.4℃（ta）, 26.7℃（top）, and 28.5℃（ET*） respectively, and the upper boundary of the 80% acceptable temperature range is 29.0℃（ta）, 29.4℃（top）, and 31.2℃（ET*）in summer respectively. In addition, the preferred temperature in "gray spaces" is higher than that in "absolute spaces" in amount of 0.6℃, indicating that people have lower thermal expectations in gray spaces. Therefore, the architectural features that sets right amount of gray space in traditional architecture should be retained in modern rural residential buildings.

Abstract:In order to analyze the effect of different temperatures on PAOs decay, a lab scale EBPR culture with PAOs over 90%±2% of the entire bacterial was used under different conditions (10℃ anaerobic, 10℃ aerobic, 20℃ anaerobic, 20℃ aerobic). The results show that the decay rate increases with the increase of temperature; the average rate during 1~9 days is (respectively: 10℃ anaerobic, 10℃ aerobic, 20℃ anaerobic, 20℃ aerobic) 0.053/d, 0.50/d, 0.072/d, and 0.145/d; the cell death rate is 0.019/d, 0.017/d, 0.019/d, and 0.03/d, which accounts for 35.8%, 34%, 26.4%, and 20.7% of the decay rate, respectively. The concentration of PHA and glycogen decreases during the decay period. And Glycogen degrades quickly in anaerobic conditions than in aerobic conditions under the same temperature. The glycogen degrade rate is higher with the increase of temperature under the same anaerobic and aerobic conditions.

Abstract:The effect of phase operating time on pollutants removal efficiencies in CMICAO process was investigated at low temperature, and the relationship between DO, ORP, pH and the removal efficiencies was discussed. At 8~10 ℃, when SRT was 13 d, HRT was 16 h, sludge concentration was 2 680~3 560 mg/L and sludge return ratio was 30%, the optimal operating time of six phases were 3, 2.5, 2, 3, 2.5 and 2 h, and the concentrations of TN, ammonia, NO3--N and TP in the effluent were lower than 10.1, 1.1, 7.4 and 0.8 mg/L, respectively. When nitrification finished, pH began to rise from the fall and ORP and DO rose to flatten. When denitrification ended, ORP dropped significantly and pH rose to flatten. ORP flattened when phosphorus release finished. The DO reduction in the ex aerobic tank contributed to SND, which improves nitrogen removal efficiency and saves energy accordingly.

Abstract:Utilization of high calcium fly ash geopolymer to solidify/stabilize heavy metals was explored. The solidification/stabilization effectiveness of heavy metals was studied using static and dynamic leaching experiments. Additionally, transferring mechanism and long term safety of heavy metals in geopolymer were also investigated. The results show that the leaching concentrations of heavy metals from the solidified/stabilized matrix were far lower than the limit values, and all the solidified/stabilized ratios of heavy metals reached 98% when the geopolymer solidified/stabilized 0.025% Pb(II), 0.025% Cr(VI), and 0.01% Hg(II), respectively. The results Dynamic leaching experiment show that real time leaching concentrations of heavy metals were lower than allowable maximum values, and the accumulated leaching concentrations became stable after 72 h. After dynamic leaching experiment, the radial distributions of heavy metals in geopolymer specimens were similar. Effective diffusion coefficient and dynamic leaching ratios of heavy metals from geopolymer were very low, and this geopolymer has a good long term safety.

Abstract:Preparation technology of fiber toughened self compacting high strength concrete was tested by measuring influence of water/binder ratio, sand percentage, and steel fiber content on spread, T500 time , U shape value, and L shape value of fresh concrete. Mechanical properties were analyzed in case of different water/binder ratio, sand percentage, and steel fiber content. The test results show that suitable W/B and sand percentage were necessary to satisfy self compacting performance of the fresh concrete. With the increase of steel fiber content, the compressive strength and flexural strength were improved while workability of fresh concrete was cut down. Steel fiber toughened self compacting high strength concrete was prepared successfully with a strength grade of CF90 and a flexural strength of more than 11.0 MPa.

Abstract:The characteristics of recycled fine aggregate (RFA) and its concrete (RFAC) were analyzed by SEM, EDXA, XRD, Micro harness and nitrogen absorption. The results show that RFA is an artificial aggregate with complex compositions, certain hydration activity and high permeability. The mineral compositions of RFA include SiO2, CaCO3 and a small quantity of C2S, which has a certain hydration activity and can form hydration productions. The compaction rate of cement paste in RFAC is low because of pores in it. There is obvious interfacial transition zone (ITZ) between RFAC and cement paste, and its width is bigger than that in ordinary concrete. In addition, the values of micro hardness of the interfacial transition zone on both sides of RFA and cement paste are lower. The porous structure of the recycled fine aggregates and defects of ITZ are main reasons for big pores in RFAC, which has bad effect on impermeability of RFAC.

Abstract:Response surface methodology was adopted to optimize waterglass preparation process, and silica aerogels were synthesized under ambient pressure drying with optimum condition. Experimental results show the optimum conditions are: alkali silica ratio 3∶10, alkalinity 10%, and reaction temperature 90 ℃. The morphology structure and other properties of silica aerogel based on diatomite were characterized by N2 physical adsorption, XRD, FESEM, TEM, FTIR and TG/SDTA measurement. The results indicate that silica aerogel is crack free amorphous state solid, with the density 0.132～0.143 g/m3 and the specific surface area 755.5 m2/g, and it exhibits a sponge structure and a narrow pore size distribution. In addition, the hydrophobicity of aerogel can maintain up to 400 ℃。

Abstract:With foamed concrete as the absorbing substrate, under rapid water loss, the hydration mechanism of cellulose ether modified thin layer cement pastes was studied. The cement pastes were divided into three layers from surface to interface. Each layer cement paste of 6 h, 12 h, 1 d and 3 d ages was analyzed by using water loss speed, moisture content, XRD, FTIR and TG DSC DTG. The results show that cement pastes of different layers quickly lose water when hydration time is less than 6 hours and characteristic diffraction peaks of Ca(OH)2 are detected only in the second and third layer. The water loss speed significantly decreases when hydration time is more than 12 h and characteristic diffraction peaks of Ca(OH)2 are detected in every layer. The content of Ca(OH)2 increases continuously from the first layer cement paste to the third layer cement paste and aggregation state of ［SiO4］4- in C S H gel changes. The intensity of diffraction and vibration peaks of Ca(OH)2 within cement pastes increases as hydration time prolongs.

Abstract:Isothermal calorimeter, thermal analysis and scanning electron microscope were employed to investigate the impact of 3 polycarboxylate based superplasticizers (PCs) on the hydration behavior of tricalcium silicate (C3S). In addition, adsorption isotherm was measured by total organic carbon. The results indicate that PCs extends the induction period of C3S. Initial hydration process of C3S is markedly retarded, whereas acceleration is observed in the period of 28 d. And it is found that PC1, with maleic anhydride for its main chain, has the strongest retardation effect. The majority of the copolymer dispersants is remained in the pore solution. Moreover, linear relationship between the content of COO- and its retardation effect is established. Accordingly it is presumed that the critical supersaturation with respect to portlandite can be expected to have a profound impact because of the addition of PCs.