Abstract:In tall buildings the reinforced concrete (RC) shear wall is one of the predominant structural components used to resist earthquakes. Because shear walls located on the bottom zone of high rise buildings are subjected to large axial load, shear force and moment during severe earthquakes, the shear failure or crushing of concrete usually occurs in the bottom zone of walls, and such failure mode is irreparable. Therefore, the improvement of seismic performance of RC walls at the bottom is one of the key issues of seismic design of high rise building structures. The observed damage of RC walls in Chile earthquake (2010) and New Zealand (2011) are firstly introduced in the paper, and correlated factors which likely result in the failure of walls are analyzed. Based on the detailed assessment of seismic behavior of RC walls, concepts and measures for improving the seismic performance of RC walls are then suggested. Meanwhile, due to the increasing use of the steel plate reinforced concrete composite shear wall (SPRCW) in super tall buildings currently, the parametric analyses of this novel structural member are carried out by numerical analysis. The numerical results indicate that, compared with the conventional RC shear walls, the embedded steel plate can efficiently improve the behavior bearing the compressive force, the load carrying capacity, ductility and energy dissipation capacity, resulting in the significant improvement of the seismic performance of RC walls.

Abstract:A conventional coupled shear wall specimen and a new coupled shear wall specimen with replaceable coupling beams were designed and tested by low cyclic loading tests. The seismic performance of two types of shear walls were studied and compared. The results show that the two specimens have similar bearing capacity. In addition, the new shear wall possesses larger equivalent viscous damping and displays less strength degradation. Moreover, the replaceable coupling beam of new shear wall make the structural damage concentrate in the fuses, while the other parts of replaceable coupling beams keep intact, which is beneficial to replace the damaged fuse after the earthquake easily.

Abstract:This paper presents a low frequency cyclic loading test for spatial reinforced concrete(RC) frames. The main research content in the study is the effect of the cast in situ slabs on the seismic performance of frames. The failure pattern of frame, hysteretic loop, strain of the slab longitudinal reinforcement, moment of beam and effective slab width were experimentally studied. Research findings indicate that the “strong column weak beam” can’t be realized due to slabs; the frame with cast in situ slabs has a good dissipation capacity; the strain of slab longitudinal reinforcement increases while the story drift increases, which indicates that the participation of slab increases; the moment of beams are enlarged by slabs. Finally, the strut and tied model (STM) is developed to calculate the effective slab width. The analysis results agree well with the test results, and the participation of slab on the seismic response of RC frames is better reflected by STM model. The formula can be applied to the construction engineering practice.

Abstract:A one fourth scaled precast concrete frame structure model, which was made of recycled aggregate concrete(RAC) with 100% replacement percentage of recycled coarse aggregate, was tested on the shaking table with 3 different seismic wave inputs. Dynamic characteristics such as natural frequency, vibration mode, damping ratio were assessed through white noise scanning. Acceleration, inter storey shear force and displacement dynamic response were investigated. Damage phenomenons during the test were described in detail. The test analysis indicates that the natural frequency descends, the damping ratio ascends and the acceleration amplifying factor decreases gradually, the inter storey shear force increases gradually with the increase of seismic intensity. In the later elasto plastic stage, the deterioration of joint stiffness is quite rapid and the inter storey drift is much larger obviously. The inter storey drift is adopted as the index to evaluate the seismic performance of the precast RAC frame structure, which shows that the precast RAC frame structure has good seismic performance and some measures should be taken to enhance the energy dissipation of the beam column joint if it is applied to practice.

Abstract:Based on the generalized Biot theory model of incompressible saturated porous media model, a finite element formulation for dynamic transient of fluid saturated two phase porous media is presented, the numerical simulation model directly aiming at the soil site of Hong Kong, Zhuhai and Macau long immersed tube tunnel project. The result of numerical simulation indicates that: PGA of the saturated two phase porous medium free field reduces in comparison with traditional single phase medium free field; the topography of complicated soil site has a significant influence on the peak of pore water pressure; a greater permeability coefficient of porous materials may result in a lower pore water pressure; also the magnitude of input seismic action will affect the assessment of earthquake induced site liquefaction. Therefore, the numerical simulation method based on incompressible saturated porous medium is feasible in the analysis of earthquake induced site liquefaction and the conclusion can be applied to other soil site projects.

Abstract:Based on nonlocal theory and stochastic damage mechanics, a nonlocal micro damage model is developed. By introducing the residual stress factor, the plastic slip effect on damage is reflected. Avoidance of spring layer sensitivity can be achieved with nonlocal proportion. A two scale damage model provides knowledge about strain development, damage evolution and elaborate stress and strain relationship. The non local proportion based analysis leads to stable and reasonable results, which agree well with experimental data.

Abstract:Two static tests of pinned connections between primary and secondary H beams with corrugated webs were conducted. The test results were compared with the results calculated from theoretical formulas, which validated the theoretical formulas. Design formulas for each part of the pinned connections between primary and secondary H beams with corrugated webs were proposed. The design carrying capacity of each part calculated by the design formulas were compared with the experimental results, which proved the reliability of design formulas for the pinned connections between primary and secondary H beams with corrugated webs.

Abstract:Strands model or parallel model based on the assumption of parallel wires is helpless to a mechanical analysis of semi parallel wire cable for its helical characteristics and complex structure. Based on the theory of Love’s curved bar, the mechanical model for multilayered semi parallel wire cables under static tensile loads with non symmetric wire breaks were derived with a consideration of the deflections perpendicular to the tendon axis in the direction of the break wire, and the inter wire contact and friction. Distributions of wires’ axial force and related influence parameters are discussed by numerical calculation and parameter analysis. A comparison with the parallel model shows that non symmetric wire break leads to the marked non uniform distribution of wire axial force, and the parameters that affect the most the distribution of wire axial force are the inter wire friction coefficient and radial position of the break wire.

Abstract:This paper presents results from experimental research and finite element method investigations on the ultimate strength of K type tubegusset plate connections with negative eccentricity or without eccentricity. Static tests on four large scale specimens indicate that connections with negative eccentricity and those without eccentricity have the similar failure modes and the connections with negative eccentricity are feasible in practice. Finite element models are employed to simulate the test loading procedure and to facilitate the parametric study on the ultimate strength of the connection. Based on a comparison between FEM results and assessment by existing design guides, a new ultimate strength equation is proposed to incorporate a reduction coefficient in terms of the chord stress effect. The effect of side stiffeners is also investigated to provide reference for application.

Abstract:According to the structural characteristics and static equilibrium of the joints, immersed tube tunnel three dimension nonlinear stiffness mechanical model was established, with which the joints’ displacement in all degrees of freedom could be calculated. Furthermore, the harmonious relation for deformation and stress strain relations of GINA and OMEGA gasket were considered. The different operating modes of the joints were divided and identified by the relative displacement of the shear key. With this model, the joints’ mechanical characteristic was analyzed and the nonlinear relation between the joint displacement and the joint’s internal force was also obtained.

Abstract:The seepage coupling model, the seepage theory, and the soil permeability as well as the influence of dewatering on soil strength were analyzed and discussed based on a summery of seepage coupling theory of foundation pit engineering at home and abroad. Results show that the seepage coupling model can not only reflect complex stress path and nonlinear characteristics of soil, but also can reflect the interaction of seepage field and stress field due to deep depth of excavation, large scale of excavation and complex retaining system of super deep foundation pit engineering. Under the effect of high hydraulic gradients, the seepage of super deep foundation pit engineering may deviate from the Darcy law, and the permeability coefficient of the mixed soil composed by unsaturated soil, saturated soil and water resisting layer is no longer a constant, but the function of strain filed. Test results show that the influence of dewatering of super deep foundation pit engineering on soil strength cann’t be ignored, therefore, it is an important research field about seepage coupling analysis of super deep foundation pit engineering that explores quantitative relationship between the amount of dewatering and strength parameters of soil. In conclusion, in order to meet the needs of engineering practice, it is urgent for seepage coupling analysis of super deep foundation pit engineering to make improvement and innovation in the seepage coupling model, the seepage theory, the dynamic change of permeability coefficients and so on.

Abstract:Compared to the vehicles’movements, the pedestrians’ are more flexible and exhibit high intelligence. In general, in order to achieve the best moving performance, a pedestrian moves based on a full evaluation of one’s surrounding environment and the prediction of the environment evolution. How to quantitatively describe pedestrians’ intelligence is one of the emphasis and difficulties in the field of pedestrian study. A pedestrian framework is proposed by introducing the concept of field. Through translating pedestrians’ active intelligence into the passive strength imposed at their location by presumed pedestrian fields, pedestrians’ intelligence can be mathematically modeled. Results indicate that many practical pedestrian phenomena such as oscillation of pedestrian flow near an outlet, pedestrian automatic lane formation, separation of pedestrians due to implicit right side moving can be reproduced quite well in computer simulations.

Abstract:The relationship between origin destination (OD) and production attraction (PA) matrix was analyzed, and it was pointed out that they often corresponded with different time intervals. An analysis on the limit of peak hour factor argued the necessity of trip classification, and the method to estimate the ratio of each class was proposed based on trip chain and trip purpose structure. Then, with the help of hourly departure and return ratio index, the linear transformation relationship between day long PA matrix and peak hour OD matrix was argued, and the feasibility of PA matrix estimation was demonstrated theoretically. Besides, a human computer interaction interface was programmed. At last, an example was adopted to testify the effectiveness of the findings.

Abstract:Urban interrupted flow travel time probability distribution models are presented based on conventional travel time unimodal distribution. Six types of bimodal probability distributions which apply normal distribution and lognormal distribution as typical distribution are modeled. The parameters of those models are calibrated by Least Square(LS) and Frank Wolfe algorithm. The study results demonstrate that bimodal distributions, in comparison with unimodal distribution, can fit the real data better and highlight the features of interrupted flow. The research contributions can provide an update link cost definitions for path finding in urban network. Meanwhile, the update link travel time probabilistic function can be studied for traffic assignment based on these contributions.

Abstract:Based on a coastal tourism highway of Hainan Province， an experimental research was made into the treatment of silty fine sand foundation with impaction and grind method (IGM). In situ tests (SPTs, DPTs), compaction test, deflection test and real time monitoring data of groundwater level, pore water pressure and surface settlement were adopted to discuss the effectiveness and construction technology of the silty fine sand foundation with the impact roller compaction method. The results show that the key to an effective treatment of silty fine sand foundation with impaction and grind method is to take the excess pore water pressure dissipation rate at least 70% in saturated silty fine sand shallow foundation as the control standard of next round of the impact roller compaction. The reasonable construction technology not only can effectively improve the strength of silty fine sand foundation, but also can eliminate liquefaction shallow silty fine sand foundation. After the treatment, the subsoil up to the depth of 2 m is well improved.

Abstract:The chlorination kinetics of N nitrosodimethylamine(NDMA) precursor, Chlortoluron, controlling different concentrations of bromine ions under different pH,was investigated in this study. Results show that degradation of Chlortoluron still meets pseudo first order dynamic model when different dosages of bromine ions are controlled at scheduled pH of 6, 7, 10 (concentrations of Chlortoluron and Cl2 are 9.4 μmol·L-1 and 188.0 μmol·L-1, respectively). The degradation rate of Chlortoluron increases with concentrations of bromide ions at pH 6 and 7. Chlortoluron degrades faster under more acidic conditions. This phenomena are probably related to the generation of HOBr in the system. Nevertheless, when pH is 10, variation of bromide ions has no significant impact on the degradation rate, which may be attributed to non reaction of ClO- and Br- and no generation of HOBr. Based on the kinetics analysis, this study obtains the linear relationship between kobs and ［Br2］/［Cl2］ at these pH conditions. Then by solving ordinary differential equations, the reaction rate constant of HOBr and Chlortoluron is calculated(k5=(1.95±0.44)×105). Simultaneously, from viewpoint of dynamics, this relatively far high rate constant also explains the distinct faster degradation rate of Chlortoluron with the presence of bromine ions.

Abstract:A wavelength of 185nm UV was utilized to threat microsystis aeruginosa by immersing into the solution, optical density, chlorophyll a, soluble protein and cellular structure variation was investigated through contrasting with conventional radiation pattern. The effect of initial algae concentration and aeration capacity was also studied. The results show that, optical density, chlorophyll a and soluble protein decrease by 83.9%, 99.5% and 97.0%, which are much better than those by conventional methods. With the increasing of the initial algae concentration and the aeration capacity, the removal rate of chlorophyll a and soluble protein decrease, but not evidently. That the catalytic effect of oxygen on algae removal is not evident during the immersion. Scan pictures show that 185 nm damaged microsystis aeruginosa cellularity in short time, intracellular and extracellular substance structure changed evidently and algae cell turned to abnormality. Algae growth rate and physiological activity decrease by immersion pattern. Mass of strong oxidized radical acts on the algae cell directly, which removes each item more than conventional UV radiation. And no photo reactivation phenomena appeare in the following cultivation process.

Abstract:Accidental water pollution and rapid diffusion of the pollutant terribly affect water quality in the distribution network; the consumers complaint information to water utilities is an important way for monitoring the condition of the water supply systems timely where there is lack of monitoring station. The research first uses the location information of consumer complaints to find the candidate pollution source nodes through the improved pollution matrix methodology. And then the probability of each candidate pollution source node is calculated on the basis of the total probability formula and evaluated by Borda Count and Normalization Count to identify the most possible pollution source. The feasibility and effectiveness are verified through a source contamination event in a city.

Abstract:To make a research on flow characteristics around wheel, simplified isolated wheel is applied under different conditions including stationary and rotation with different yaw angles by computational simulation, which is validated by experiments. Particularly, steady Reynolds Averaged Navier Stokes (RNS) calculation is adopted in simulation in combination with experiment in a scaled wind tunnel of 1:15. Further, detailed analyses on local flow, surface pressure coefficient, drag coefficient and lift coefficient of wheel in different conditions figure out that rotating wheel affects the flow around the isolated wheel significantly. Pressure difference, drag coefficient and lift coefficient are decreased by the rotation, which improves aerodynamic performance.

Abstract:According to the forming characteristic of the auto inner panels, Dynaform software and orthogonal method were applied to simulating the forming process with different process parameters. BP neural network was used to establish a network relationship between process parameters and forming defects. Finally, the proper parameter ranges were obtained. The experimental results indicate that process phase diagram can reflect the process of sheet metal stamping accurately, which is efficient to the actual production.

Abstract:An investigation was made into steady state heat transfer mechanism and optical properties of frame supported glass curtain walls (FSGCW) are investigated. The differential method was applied to establishing the numerical computation model of the heat transfer and optics performances of glass systems. Based on the two dimensional steady state heat transfer theory, the thermal performance finite element model was derived and established for frame systems in boundary conditions of convection, radiation as well as the couple of them. The FSGCW thermal performance analysis software was developed based on the secondary compiling of the AutoCAD using Visual C++ and ObjectARX. The proposed theory and numerical method was verified on the basis of a comparative study of various prevailing commercial softwares.

Abstract:The study measured shading coefficients and optical performance of three kinds of rollers, and then the combined cooling and lighting energy consumption and combined energy saving coefficients were obtained. A typical room and window to wall ratios were established to assess the impact of shading devices on the cooling and lighting energy consumption. The results show that the roller with high visible transmittance and a low shading coefficient is more energy saving. When the window to wall ratio equals to 0.3 and 0.5, respectively, the energy saving rate of the roller reaches 66% and 47% correspondingly in comparison with the standard glass. When the window to wall ratio is 0.3 and fluorescent lights are used, the control logic of the roller can save energy by 5.4%. If halogen tungsten lights are used, the control method even can save energy by 20.7%. Based on the simulation and calculation results, when outdoor daylight and thermal environment are taken into consideration, energy saving shading devices are proposed to have high visible transmittance and solar light reflectance.

Abstract:The equilibrium moisture content under different humidity conditions of four test samples was tested. The weight changes of the samples were measured every hour at different temperatures with the relative humidity (RH). Experimental results indicate that in the same air environment the relationship between dimensionless absorption/ desorption rate and the time can be fitted by the same power function. Through numerical fitting, the expressions of the dimensionless absorption and desorption rate were obtained with the ambient humidity 75%RH and 95%RH respectively. The relative error between the calculated value and the measured value of moisture absorption/desorption rate at any hour during the 12 hours was also formulated.

Abstract:An advanced statistical method, linear regression model, is proposed to construct the power leakage model for the differential side channel analysis (DSCA) attacks on cryptographic devices. Even with only a limited knowledge on how the device leaks information, the linear regression leakage model can be constructed, which overcomes the limitations of the traditional leakage models. First, the stochastic approach for analysis of power leakage is investigated and the linear regression model is built. Then the coefficients of the linear regression model are estimated with two methods: least square estimator(LSE) and least absolute estimator(LAE). Finally the mathematical model and methods are realized by an experimental analysis of an advanced encryption standard(AES) implementation on an 8 bit microcontroller based PayTV smartcard platform. A comparative analysis of both estimators shows that LSE is more suitable than LAE concerning the linear regression analysis of leakage model. In addition, investigation on the curves of the estimated model coefficients shows that linear regression analysis can be applied to preprocessing the measurement traces and the preprocessing helps to increase the efficiency of leakage modeling.

Abstract:Photovoltaics and phase change material(PV/PCM) component system was produced through a combination of low melting point paraffin and polyethylene glycol. The experiments studied the temperature control effect of PCM on PV/PCM with different composition and thermal structures. The temperature radiation power curve of PV/PCM system was tested with both laboratorial and field study. The study reveals that temperature controlling period can be lengthened with the increasing PCM content, however no explicit linear relationship is confirmed. The polyethylene glycol is a better temperature controlling PCM and steel wire enhances the heat conduction significantly. The PV/PCM system composed of polyethylene glycol reaches a maximum cooling degree to 30 ℃, cooling period to 6 hours. The open circuit voltage of the system increases by 6%, and the power increases by 10%.