Abstract:General mathematical expression of strength degradation is established for reinforced concrete members. The concept of strength degradation function is set with damage index being its variable. It is pointed out that the essence of strength degradation model is to determine the strength degradation function. The specific expression of the strength degradation function is established based on a set of experiments made in Kamashima Library in 1997. The influence of loading paths on the strength deterioration is examined in these experiments. The numerical result and the experimental phenomena are in good agreement. The established hysteretic model can reflect the strength degradation phenomenon well. The proposed hysteretic model is further proved to be suitable by another group of tests made by Kunnath K S, et al. in 1997.

Abstract:According to the failure modes of perfobond rib connector, the failure mechanics of the connector with/without penetrate reinforcement in the hole were carefully analyzed. Based on the failure mechanism of the connectors, the calculation method for computing the shear bearing capacity of perfobond connector was proposed by theoretical approaches. Compared with testing results, the calculation results well matches the test values, which indicates the new calculation method has adequate accuracy and it can be used in engineering design preceeding.

Abstract:Based on the first order shear deformation laminated plate theory (FSDT), a new three node triangular laminated plate element, labelled here as composite discrete shear triangular element with 6 extra shear degrees of freedom(CDST S6), is proposed. The transverse shear strains and rotations of the element are the same with DST S6. The proposed CDST S6 can eliminate the shear locking without any numerical expediencies such as the reduced integration, the use of the assumed strains/stresses, or the need for the stabilization of the attendant zero energy mode. The expression of the CDST S6 is simple in formulation and easy to be implemented by using finite element method. Numerical examples indicate that the element has high accuracy and high convergence rates for solving thin or thick laminated plates.

Abstract:In order to facilitate the construction of industrial buildings, a new type of splice joint, named flange bolted welded hybrid joint, was designed to splice I shape beam to steel connections. The flange, welded with the bottom beam flange as well as the web close to bottom flange, was jointed by high strength bolt. Stiffening plate was welded at top of the flange. While downhand welding and high strength friction grip bolts were used for the top beam flange and the beam web, respectively. Monotonic and reversed cyclic loading tests were conducted on three specimens of this innovative joint to investigate its load bearing capacity, energy dissipating capacity and failure modes. The experimental data indicate that the joint has high load bearing capacity and great rotational ductility with the maximum plastic rotational angle up to 0.095 rad. The strength of specimen will be increased after rotational ductility for the reason that its high strength friction grip bolts transform to bearing type. The failure mode is due to the looseness of bolts connecting flange plate as well as the development of gap between the flange plate.

Abstract:Based on the percentage of human perception of the vibration of the building under wind load, the human comfort performance of the building was classified into five levels. The maximum acceleration was adopted as the quantitative index of the performance. Pseudo excitation method was employed in the frequency domain analysis for the calculation of the reliabilities of each performance of the super tall building under random wind force. The randomness of the wind speed being taken into consideration, the failure probabilities of the human comfort levels were obtained for the whole life cycle. A failure model for the wind induced human comfort of super tall buildings was derived base on the cost effectiveness criterion. This model evaluated the life cycle cost of the different design schemes, which could help make design choice based on the minimum life cycle cost criteria. It is of great significance to the performance based wind resistant design. The proposed method was applied to the human comfort design choice of a super tall building with tuned mass damper (TMD) device to illustrate its effectiveness and applicability.

Abstract:A three dimensional seepage coupling finite element modeling using Z_Soil3D was performed on a reinforced soil embankment/wall(RSW) on soft clay. The settlement，horizontal displacement，geogrid strain, and stability of the RSW were analyzed and compared with the measurements as well as the calculation results from 2D finite element program Plaxis2D. The results show that it’s reasonable to use the equivalent vertical conductive coefficient to simulate the foundation treated with prefabricated vertical drains. The calculated foundation settlement and RSW deformation varying with time agree well with the measurements. Compared with 2D FEM, 3D FEM can more deliberately simulate the elements of geosynthetics, soil and their interface and consequently well capture the bulging of RSW facing during step loading. The calculated strain of each geogrid increases with an increase of foundation settlement and the strain of base reinforcement reaches the maximum value of those all, which agrees with the finding of variation of geosynthetics strain with foundation settlement. The simulated slip surface which exhibits arc in plan view is in consistence with the observed failure mode of the RSW. Therefore, 3D FEM is more capable to capture the behavior of this RSW on soft clay.

Abstract:The thin layered method (TLM) is adopted to derive the solution of Lamb’s problem for layered saturated foundation under the action of dynamic loads. The displacement expression in the frequency wave number domain for layered saturated medium is obtained by discreting Biot’s axisymmetric dynamic equation in vertical coordinates, and by the Fourier series decomposition in tangential coordinates and Hankel transform in axial coordinates. Then the inversion of Hankel transform and Fourier synthesis are used to get the displacement expression in the frequency domain. Combined a moving train track ground interaction model, a parametric study is given to evaluate the ground vibration induced by train moving loads on the saturated layered ground. The effect of the soil parameters, such as permeability coefficient, porosity, fluid viscosity coefficient and shear wave velocity, on the attenuation of ground vibration is investigated and discussed in detail. The results show that the parameters of the first layer affect ground vibration induced by train more significantly than those of the second layer. It is also found that the permeability coefficient of soil, the fluid viscosity coefficient, porosity and shear wave velocity have great influence on the ground vibration.

Abstract:In order to obtain the distribution characterization and influence factors of subgrade moisture in humid zone, four expressways were investigated by coring method or time domain reflectometry(TDR) probes. The results indicate that, the groundwater table is a main factor affecting moisture distribution in clayey subgrade beneath pavement, the equilibrium gravimetric water content is about 5% higher than optimum water content; the infiltration through the uncovered shoulder and slope can increase the subgrade moisture under the outer lane, and result in the wetting and drying cycles; the poor drainability of unpaved median also leads to the water accumulation under the inner lane; the sandy subgrade is less influenced by groundwater, and the lag between rainfall and subgrade moisture variation is shorter. So, the durability of drainage facilities should be taken into consideration in highway design, and the material parameters should be selected based on equilibrium moisture content determined by underground water, especially on the actual moisture content beneath the outer lane.

Abstract:Based on the field test data of Shuo Huang heavy haul railway subgrade and the reinforcement mechanism of inclined high pressure jet grouting piles (IHJGP), a study was made of the comprehensive reinforcement effects of this technology. Studies show that the strength, the stiffness, the bearing capacity and the soil compactness of the subgrade reinforced by IHJGP improves significantly, which proves that IHJGP is an effective reinforcement technology for the existing railway embankment.

Abstract:It is realized that there exists a point called the inertial point in the pavement deflection basin whose deflection does not vary with the modulus of the upper layer, provided that the subgrade modulus and the upper layer thickness remain unchanged in cement concrete pavement. In order to make the theoretical deflection basin and measured deflection basin match each, the writer of this paper takes the rigid substratum into the calculation of theoretical deflection basin. As a result of a significant amount of calculation, the writer found it’s very difficult to get inertial point in asphalt pavement structure. Since that, the writer developes a new method of selecting inertial point based on smallest criterion of root mean square error and applies it to the back calculation of the subgrade modulus. It is found that the value of base modulus contributes more to the precision of subgrade modulus backcalculation and the writer draws a conclusion about the relationship between the inertial point parameters and the structure information on both flexible base and semi rigid base. The writer demonstrates the precision of the induction formula theoretically through the back calculations in different pavement structures, the precision and the reliablility of subgrade modulus backcalculation method based on inertial point using measured deflection basin are verified by a comparative study of the backcalculation programs at home and abroad.

Abstract:Voids play an important role in the micro structure characteristics of asphalt mixtures, since moisture damage and aging will occur with the existing of water and air. In addition, voids are the weak points and defects in the mixture which are closely related to the force bearing performance and the damage process. A graded particle flow model of asphalt mixture was built up using discrete element method(DEM) package. The DEM fluid coupling analysis framework was used to calculate the parameters of each void such as volume and position. Finally the obtained voids distribution pattern was compared to actual results from CT scan and image analysis. It proves that the scheme employed in the paper is effective and reasonable.

Abstract:A light weight concrete layer is placed between steel deck slab and asphalt layer to compose a new steel bridge deck pavement system. In order to research the mechanics characteristics of the new deck pavement system, a large scale model is prepared, and the mechanics response of steel deck slab and deck pavement are measured under different vehicle load positions. Results show that the biggest transverse tensile stress of steel deck slab is 90 MPa, but it decreases to 43 MPa after being set the ribbed stiffener, that is to say the ribbed stiffener is useful to improve the load capacity of the steel deck slab. After paving the light weight concrete layer, the maximal stress and displacement of top steel deck slab and bottom ribbed stiffener also decrease. The maximal stress decreasing amplitude is 48%, and the maximal displacement decreasing amplitude is 18%. Meanwhile, the stress distribution of steel deck slab is more uniform. As a pavement layer, the light weight concrete layer jointly participates the load bearing together with the steel deck slab, and the stiffness of the bridge deck pavement system improves.

Abstract:The characteristics of highway emergency rescue site location planning were first analyzed from four aspects including the functional requirement, location impact factors, location elements (customers, facilities, space and measurement) and location objectives of emergency rescue site. Based on three objectives in rapid response, set covering and disaster loss minimum, a multi objectives decision model for location optimization was established. Then the algorithm and procedures of this model were discussed and the optimized objective was achieved through the Lingo programming. Finally, the method of rescue site planning was applied to the Tonglu highway network in Zhejiang Province.

Abstract:Due to an insufficient section inspection data, toll ticket data were resorted to predicting the travel time between highway toll stations. First, a research was made into a processing method to modify the toll ticket data on real time, and an average travel time calculation model was developed. Then, in order to decrease the model deviation caused by Kalman filter model linearization, a piecewise linear interpolation method was introduced to build the Kalman filter model. Finally, the application system was developed according to the travel time prediction business logic, the system could accurately predict the travel time between highway toll stations on real time. Actual road application shows that the interpolation algorithm can improve travel time prediction accuracy compared to the conventional Kalman filter method in the normal, accident and holiday traffic flow. The relative error of all prediction periods is less than 10%, and the relative error of accident prediction periods is less than 13%. The prediction accuracy of interpolation algorithm is improved effectively, which can provide an effective time reference for public in highway.

Abstract:Based on the optic requirement of insulation coating used for outside wall in plateau, cold and freezing area, lots of experiments were made for research on the influence of metal paint on insulation coating with low emissivity and solar reflectance. The results indicate that the infrared emissivity of oil insulation coating is digressive evidently with metal paint such as copper, aluminum and nickel. The infrared emissivity of coating is influenced by kinds of metal paint, dosage and shape of metal powder. Copper is the best. The best dosage of these metal paints is about 40%~50%. The effect of sheet copper powder on the decrease of the infrared emissivity for oil insulation coating is better than the spherical powder, and the floating aluminum powder better than the non floating. For water soluble coating, the infrared emissivity is digressive evidently with soluble aluminum powder and the infrared emissivity and solar reflectance decrease, but the powder particle size increases instead. The above insulation coatings are approximate with the optic requirement of insulation coating used for outside wall in plateau, cold and freezing area with infrared emissivity upto 0.35~0.45 and solar reflectance 0.39~0.56.

Abstract:The hydroxyapatite (HAP) modified by dimer acid was prepared in different solvents under different technology conditions by using C36 dimer acid and porous hydroxyapatite as raw materials. The structure of the modified hydroxyapatites was characterized by Fourier transform infrared spectrum analyzer (FTIR), laser particle analyzer, Bet surface area analyzer (BET) and scanning electron microscope (SEM). The progress of reaction was estimated by thermogravimetric (TG) ananlysis. The results show that the porous hydroxyapatite modified by dimer acids can be obtained at the reaction temperature of 105~110 ℃, the dosage mass ratio of C36 dimer acid to porous hydroxyapatite of 1∶1 and in the solvent of ethanol for 3.5~4.0 h. Under the above reaction conditions, the progress of the reaction was estimated by 36% or so. The dimer acids are on the surface and in the pore structure of hydroxyapatite which results in the decrease of the porosity of HAP. After the modification by dimer acids, the particle size of HAP decreases from 4.149 μm to 3.595 μm. And the BET specific surface area of HAP decreases from 60.6 to 28.0 m2·g-1.

Abstract:Some accelerated experimental methods are usually applied to measure the sulfate attack resistance of concrete due to very slow sulfate attack process in actual engineering. With taking account of characteristics of the accelerated methods in application and research of cement concrete nowadays, a new accelerated experimental method for assessment of the sulfate attack resistance is proposed based on electrical pulse. Corrosion resistant coefficient of concrete with different water/cement ratio, different soaked ways and fly ash replacement of cement were measured under the different corrosion condition. The mechanism of sulfate attack in the case of electrical pulse was tested using scanning electron microscope (SEM). The test results show that sulfate attack process of concrete was accelerated under the action of electrical pulse. Accelerated test menthod of sulfate attack resistence based on electrical pulse is feasible.

Abstract:To analyze the flow fields of an electric driven vehicle with four in wheel motor, the computational results of flow fields were obtained with front end airflow simulation, so the external flow around the wheels of an in wheel motor vehicle in detail conditions was obtained. At the same time, the results of an in wheel motor vehicle and a conventional vehicle were compared for local and global flow fields. Furthermore, the ventilation of in wheel motor system was annlyzed, which provided aerodynamic data for thermal dissipation of brake and in wheel motor.

Abstract:A systematic design process for the electrified manual transmission(eMT) is proposed on the basis of a morphological analysis. First, the independent design parameters, its feasibility constraints and consistency conditions need to be defined by analyzing the structure and functions of eMT. According to these boundary conditions, structure variables such as the number of components and the connection type can be solved to synthesize the component types. Then, the scheme number of each structure type is synthesized. After the abstraction from practical mechanism to topology model, the corresponding matrix is attained. All transmission paths can be gained by the analysis of the matrix. Based on the paths, the schemes concerning component layout and operating mode can be gained. Finally, all transmission schemes meeting the structural and functional requirements are synthesized.

Abstract:Based on the grey correlation analysis, a study was made of the effect of the structural parameters of blast furnace (BF) cooling stave on the highest temperature and the thermal stress of the hot surface. The structural parameters included the radius of cooling water pipes, the space between cooling water pipes, the distance between the cooling water pipes and hot surface and the thickness of stave. Study results show that when the radius of the cooling stave is 20 mm, the space between cooling water pipes is 220 mm and the distance between the cooling pipes is 90 mm as well as the hot surface and the thickness of cooling stave is 125 mm, the cooling stave is optimum.

Abstract:The simultaneous multi threading (SMT) technique boosts instructions per clock (IPC) by adopting thread level parallelism and instruction level parallelism. However, the competition of key resources between threads do weaken such advancement. Instruction queue (IQ) is proved as one key resource and its competition always results into performance degradation. Typical IQ competition easing strategies include Dwarn, 2OP_Block and Static. This paper presets two IQ utilization parameters to estimate the relationships between IQ usage and system performance. Competition easing capability of typical IQ strategies and their combination are compared. A load dependency chain model is built and analysis of thread characteristics based on the model is given. Then a new IQ competition easing strategy combining with thread characteristics is proposed. The experimental results show that such strategy can achieve total IPC improvement by accelerating high IPC threads.

Abstract:We focus on nonlinear optimal control to stabilizable analytic systems. By generalizing Kleinman iteration for linear system, we construct a sequence of nonlinear stabilizing feedback control, which is uniformly converging to an optimal feedback control. We present an algorithm for computing the control sequence. An example is illustrated.

Abstract:The failure detection of the energy storage capacitor is an important issue to be solved in permanent magnetic actuator for vacuum switch. Based on the operating principle of permanent magnetic mechanism, the degradation mechanism of the energy storage capacitor (electrolytic capacitor) and equivalent circuit model were studied. The equivalent series resistance (RESR) and capacitance (C) values were selected as feature parameters to identify the faults. An assessment method was proposed by introducing the system identification theory. Furthermore, the least squares support vector machine (LS SVM) algorithm was used to predict the values of RESR and C, then the capacitor’s condition changes could be obtained and analyzed. The simulation experiments show the effectiveness of this assessment and prediction method.

Abstract:Technology assignment to the established firm or start up in which faculty is a principal is two significant modes of university industry technology transfer. A model involving the inventor, licensee, and licensor was developed based on the game theory. We found that the moral hazard and adverse selection has played more crucial role on the pattern selection and license contract designing. Through analyzing the process of technology transfer, the decision baseline and boundary condition were pointed out.

Abstract:Based on 364 restatement samples and 4904 non restatement samples from 2008 to 2011 of A share stock market in China, an empirical research shows that board meeting frequency, executive compensation and whether being audited by one of Four Big Accounting Firms significantly influence the corporate governance efficiency. G established from factoring analysis is U curve related with financial restatements, proving that there exists an optimal corporate governance efficiency point. A company’s development period and agency cost also influence the efficiency of corporate governance.

Abstract:Based on a proposal and an analysis of the causation mechanism and the patterns of structural risk, a risk assessment system was established for diversified financing of urban infrastructure investment companies based on the entropy and ideal point methods. Empirical analysis from both the horizontal and vertical directions was conducted based on the panel data of 10 listed companies. The results indicate that though the company financing risk varies significantly in different regions, it is highly correlated to the regional characteristics; national supportive policies have significant positive impacts on the development of companies. However, the impacts of the restrictive policies are insignificant because of the different policies and attitudes of the central government and the local government. On the whole, the diversified financing risks of urban infrastructure investment companies in China follow an upward trend.