Abstract:First, the physical model, the mathematic model and the algorithm of structural topology optimization was stated. Next, the application of topology optimization in form finding of bridges is elaborated via some examples, and the evolution process and the final layout of structural topology optimization were presented. Finally, some issues of future research were suggested to improve the application of topology optimization in form finding of bridges. The result shows that structural topology optimization can derive a reasonable and heuristic layout in the conceptual design phase, and has a promising prospect in form finding of bridges.

Abstract:An experimental research was performed to investigate the behavior of concrete under uniaxial compression. A total of 60 prism specimens of which the strength grade ranges from C30 to C60 were tested using the MTS testing system. Based on the experimental results, the statistical characteristics of peak strengths, peak strains elastic modules and the complete stressstrain curves were obtained. Then, the randomness of concrete was studied theoretically according to the variation coefficient of strength specified in Chinese code (GB500102010). The mean curves and standard deviation curves were obtained based on the generalized probability density evolution method. The comparison between the experimental and theoretical results indicate that it is inadequate to represent the randomness of concrete only by the variation coefficient of strength. Finally, the standard deviation curves were proposed based on experiment results.

Abstract:In order to study the influence on static behavior of stud connector with different configuration layouts between the steelconcrete interface under corrosion environment, six types of layout were designed considering the relative slip between the steel and concrete. 24 specimens including 21 specimens under corrosion environment and 3 under normal environment were fabricated and used in the pushout test. The relationship between load and slip was tested during the pushout test, and the shear bearing capacity were measured. The results show that the structure with steel wrapping the concrete has a better corrosion resistance. The specimens with such layout has a higher shear resistance, and the average capacity of single stud is 177.6 kN. When the interface is slipped before the corrosion, the shear resistance is reduced compared to other specimen without preslip, and the average capacity of single stud after corrosion is 153.3 kN which is 9.6 percent less than the specimens without preslip.

Abstract:Characteristic properties of the hinge zone, defined as the concentration area of local buckling, were carefully investigated in this paper, based on which the calculation equation for the mean curvature of the hinge of Hsections failed by local buckling was proposed. Because the length of hinge zone is dependent on sectional configuration as well as axial force ratio, the calculation method for the hinge zone length considering the effects of sectional configuration and loading conditions was put forward by induction. Thus, the relationship of crosssectional momentcurvature eliminating the effect of member length of Hsections according to arbitrary cantilever beamcolumns was obtained. It is noted that such momentcurvature can be applied to nonlinear analysis of members with different loading conditions, lengths and boundary conditions, hence the nonlinear analysis efficiency of steel structures can be improved with satisfactory accuracy for engineering study.

Abstract:Under fire conditions, the load bearing capacity of steel structures reduces mainly due to the deterioration of its mechanical properties. In this paper, an experimental investigation was conducted, using both steady state and transient state methods. The comparison of test results with European, American, Australian, British and Chinese design standards of steel structures shows that fireresistance design of steel structures with S690 is unsafe according to the current design standards. Based on the reduction factors of the elastic modulus, and the yield strength and the ultimate strength of S690 obtained from this study, some specified predictive equations were proposed to describe the deterioration of mechanical properties of S690 at elevated temperatures. The predictive equations can be employed for practical fireresistance design of steel structures with members made of S690, providing reference for the revision of current worldwide leading design standards.

Abstract:In order to study the lateral resistance of reinforced damaged gluedlaminated timber post and beam structures, nine cyclic tests on fullscale onestorey, onebay timber post and beam construction specimens were conducted, including three regular specimens as the control group and six reinforced specimens as the study group. Two reinforcement methods (wrapping the joints with fiber reinforced polymer (FRP) and implanting self tapping screws in the joints) and two structural systems (simple frame and frame with kneebrace) were considered in the experimental tests. Based on the experimental phenomena and test results, the feasibility of the reinforcement was discussed, the contribution between different methods was evaluated, and the seismic performances of the specimens were studied. The results show that both the two reinforcement methods can restrain the development of crack, and recover the strength, stiffness and energy dissipation capacity, and that the lateral resistance can be improved significantly when the failed timber frame retrofitted by reinforcing the joint and adding kneebrace. This approach can be very practical in engineering.

Abstract:The differential transform method (DTM) ceases to be effective when solving the solute transport equation with discontinuous condition. In order to solve this problem, hybrid DTM and finite difference method(FDM) were adopted to solve the solute transport equation of SO42-, coupled CO2 SO42- and coupled CO2Cl- of concrete, and the approximate solutions were obtained. The comparison of the results with those obtained by FEM shows that the proposed method is effective to obtain the approximate solution of solute transport problem.

Abstract:In view of the morphology of porefilling type of methane hydratebearing sediment (MHBS), this paper proposed a new technique for generating porefilling type of MHBS. Marine sandy sediments containing porefilling type MH particles can be considered as a class of special granular materials that present apparent obvious discontinuity characteristics. To numerically simulate such materials, the distinct element method (DEM) can be used by modeling MH particles as agglomerates of spheres cemented together and filled into the pores of soil skeleton based on the specific MH saturation. The drained triaxial compression tests with different MH saturation and effective confining pressures were conducted to analyze the mechanics, deformation characteristics and contact fabric of the porefilling type of MHBS. The results show that the influence of MH saturations on the initial elastic modulus and deviator stress is relatively small. The volume shrinkage decreases with increasing MH saturations under the same effective confining pressure while the strength and the volume shrinkage increase with the effective confining pressure increasing under the same MH saturation. The shear dilatancy angle almost linearly decreases with the increase of effective confining pressure, and it linearly increases with MH saturations increasing. The grain contact direction deflects to the vertical direction with the increase of axial strain.

Abstract:A unique flexible suspend curtain wall support structure (CWSS) was ultimately developed to suit the exterior curtain wall system of Shanghai Tower. The top and bottom of CWSS are supported by the elastic boundary (MEP/ amenity floor) of main structure in each zone. The nonuniform and weak stiffness of MEP/amenity floor and heavy weight of CWSS lead to a nonuniform vertical deformation, which has adverse effects on CWSS. By means of integrated model including CWSS and main structure, the properties of cooperative work of CWSS were analyzed in detail, including the properties of nonuniform deformation of CWSS and its effect on the internal forces of CWSS and the safety of curtain wall plates. Based on the analysis results, the stiffness of MEP/amenity floor and the connection details between CWSS and main structure were optimized and adjusted in order to improve the deformation and internal force of CWSS. These optimization and adjustment measures ensure the safety of curtain wall system.

Abstract:An algorithm was proposed to automatically generate construction quality inspection points in the building information model (BIM) in accordance with national standards. First, by analyzing the role the national standards played in the process of construction quality inspection and the IFC data, the possibility to improve inspection process combined with the BIM technology was justified. Then, an algorithm was established to automatically generate construction quality inspection points based on BIM. Finally the algorithm was implemented through appropriate platforms and technologies, and its typical interface and application situation were simply explained. The algorithm lays a solid foundation for the research and development of corresponding systems.

Abstract:The plate on Winkler foundation with circumferential crack was divided into two areas under circular uniformly distributed load. Rigidplastic hypothesis was used inside the circumferential crack and linearelastic hypothesis was used outside it. Then, the elasticplastic solution to ultimate bearing capacity of plate on Winkler foundation was given. Besides, the position of annular crack was found on the condition of minimal ultimate bearing capacity, which could compensate for the defects that the location of the annular cracks could not be solved using the existing rigidplastic theory. It is more complete and has good expansibility. The result shows that the Meyerhof’s solution to ultimate bearing capacity of plate is larger and divergent when the relatively radius of circular uniformly distributed load is 2.925. The Meyerhof’s solution is 6% to 10% larger when the relatively radius of circular uniformly distributed load is between 0.09 and 0.7. Finally, a more convenient regression formula of ultimate bearing capacity of plate coefficient was proposed.

Abstract:Taking into consideration the impact of underground water and infiltration, a dynamic analysis model of asphalt pavement under heavy load traffic was established by using ABAQUS. The distribution characteristics of subgrade resilient modulus caused by moisture change resulting from underground water rising and rainfall infiltration was investigated, and the dynamic response of asphalt pavement under heavy load of threeaxis with two wheels was analyzed. It is shown that the subgrade resilient modulus is seriously affected when underground water rises, and the reduction is more significant where the subgrade is affected by rainfall and traffic load. The tensile stain at the bottom of surface course increases from 70×10-6 to 173×10-6 when the distance from underground water to the subgrade top decreases from 6 m to 2 m. Rainfall intensity has a huge effect on the tensile stain at the bottom of the surface course of outside lanes and a smaller effect on that of inside lanes. As rainfall days grow, the tensile stain at the bottom of the surface course of outside lanes declines while that of inside lanes increases which behaves in an opposite way.

Abstract:To study the influence of temperature distribution on the dynamic response of asphalt pavement, a 3D finite element model in transient mode of asphalt pavement, subjected to nonuniform moving load, was established based on the measured temperature distribution in the field and the dynamic modulus results of the actual pavement material in lab. The dynamic response time history and spatial distribution of pavement structure within the actual temperature field was analyzed and compared with that of the isothermal structure model. The result shows that the temperature simulated by the bottom temperature control method could be used to analyze the actual dynamic response during both the lowtemperature and hightemperature period in summer. The isothermal pavement structure overestimates the vertical strain and the shear strain of upper layer and lower layer, but underestimates the shear strain of the middle layer during the hightemperature period in summer. During the lowtemperature period in summer, the actual dynamic response of asphalt pavement was larger than the value calculated from the isothermal model. The isothermal model underestimates the effect of temperature distribution on the rutting and cracking potential of asphalt pavement.

Abstract:Based on the headway collection and analysis on the expressway of 8 driving lanes where a truck escape ramp(TER) is constructed, a fitting analysis and a chisquare test were conducted. The results show that the headway is an exponential distribution when the traffic flow of the driving lane on the expressway is no more than 500veh/h. Considering the traffic flow on the driving lane, and the operation speed of errant vehicles and critical headway, a vehicle merging model was proposed using the differential method. The critical headway was obtained under various road conditions through analysis of the changing lane behavior of errant vehicles. Then in the condition of 95% confidence interval of errant vehicles merged in the driving lane of the expressway, the required design length of the auxiliary lane was calculated under different road conditions, traffic flow of outside lane on expressway, and the operation speed of errant vehicles.

Abstract:An evaluation method of level of service (LOS) for urban roads considering user perception was proposed based on the grey whitenization weight function theory. The whitenization weight functions of different indices, which is suitable for LOS evaluation, were constructed. A test of LOS evaluation of several urban streets in Pudong District, Shanghai was conducted. The efficiency of the model was examined through the comparisons with the results of scoring and LOS evaluation without taking user perception into consideration.

Abstract:The roles of three kinds of pretreatment technology (ozone+online coagulation+ultrafiltration (process 1), ozone+ultrafiltration (process 2), and ozone+prechlorination+ultrafiltration (process 3)) in delaying the ultrafiltration membrane fouling were explored in this paper. The results show that the critical flux of three processes are 86.5, 59.8 and 68.1 L?(m2?h)-1, respectively. Of the three processes, the critical flux of process 1 is the largest, with the longest stable operation time (about 190 h), and can control membrane fouling to a certain extent. This can be explained by the adsorption that organic pollutants are adsorbed by colloidal particles, which can reduce the contact and interaction between organic pollutants and membrane interface by the membrane sieving intercept. Process 3 is followed with the best performance in controlling and alleviating membrane fouling due to the change of organic molecular characteristics under the effect of NaClO: 1) membrane’s flux declined and hydrophilichydrophobic property changed; 2) the increasing electronegativity of cake layer promotes the waterbackwash to remove the remaining matters and dissolves the organic matter, which results in a good transmembrane pressure recovery. By scanning with the electron microscopy (SEM), it is found that the soft filter cake layer is adhered on the surface of the ultrafiltration membrane and membrane hole is blocked by pollutants. The infrared spectroscopy study finds that the membrane surface properties are changed as some groups on membrane are oxidized by oxidation pretreatment and chemical cleaning.

Abstract:In order to reveal the Hormesis effect of antibiotics on bacterial, the adverse effects of chloramphenicol on the luminescence and cell proliferation (0 to 24 h) of Vibrio fischeri (V.fischeri) were investigated. It was found that an obvious stimulation effect at the low concentration would occur on the luminescence intensity at the lag phase of V.fischeri under the action of chloramphenicol. A possible mechanism hypothesis of the stimulation effect was then proposed, based on the light emitting mechanisms and the quantum chemical parameters calculated by Gaussian 09. It was supposed that because of a higher value of the most positive charge of the H atoms of chloramphenicol than NADH, chloramphenicol could act as proton donors to provide protons which were essential for the light emitting process, instead of NADH, and stimulated the light emitting of the bacteria.

Abstract:Energy system life cycle inventory database is the base of a product or system life cycle assessment. Due to a great variety and rapidly update frequency, the temporal validity of parameters should be considered in uncertainty analysis of life cycle assessment of energy upstream stage. Ten key parameters related to energy system life cycle carbon emission were screened by combined sensitivity and parameter time validity analysis, and the update interval of key parameters was devised. This method can reduce the maintenance workload of the database, and provide a foundation for improving the reliability of the product or system life cycle.

Abstract:A new algorithm for vehicle longitudinal velocity using the nonlinear adaptive estimation method was proposed based on distributed drive electric vehicle. According to the information of longitudinal acceleration sensor and the feedback value of each wheel slip ratio, the vehicle longitudinal velocity was estimated and algorithm proved the longitudinal velocity estimation error convergence. Depending on each wheel slip ratio, the feedback correction proportion for estimation algorithm of each wheel speed estimation error was determined. The road slope was estimated online using recursive least square with forgetting factor in rampway. In addition, the longitudinal acceleration sensor information was calibrated by the slope estimation value for slope adaptive longitudinal velocity estimation. The amount of computations for this method was small but with high estimation precision. Furthermore, the effectiveness of the algorithm was validated through experiments under multiple working conditions.

Abstract:A computational fluid dynamics (CFD) simulation was performed on a brake disc of an SUV during the repetitive braking and cooling process. The temperature rising and drop procedure were numerically investigated compared with the climatic wind tunnel (CWT) test, and the brake cooling characteristics was specifically analyzed based on the heat transfer theory. The results show that the CFD simulation and the experiments are in good agreement. The convection heat transfer acts as a key factor for the cooling performance of the brake. The temperature drop for brake disc exhibits an exponential function of the cooling time, while the cooling coefficient shows a power law increase with the oncoming velocity of the vehicle.

Abstract:Based on the mathematics modeling of the polymerase chain reaction（PCR） instrument basement, the value of process thermal resistance of the temperature variation law was obtained. Then, the process thermal resistance value obtained was used for the calculation of the the similar temperature field of key parameters, and the temperature field of a complex model was also easily solved even with some dedicated parameters. The simulation result show a relationship between the thermal resistance and the characteristic of the base of the PCR instrument. An assumption was proposed as well as a mathematics description. Finally, the feasibility of the application of this assumption is proved by numerical computation.

Abstract:Numerical simulations were conducted to investigate the reintensification of a tropical cyclone formed to the north coast of the Northern Territory of Australia in January 2006 (NT2006) with axisymmetric view. The calculations were made using the numerical model (MM5) of Pennsylvania State University/National Center for Atmospheric Research. The results show that the mergers of ‘vortical hot towers’ are nonaxisymmetric due to the high asymmetry of NT2006, which leads to the failure of Hendricks’ ‘vortical hot towers’ mechanism to illuminate the reintensifying process over land. Therefore, the azimuthally averaged absolute angular momentum surfaces were analyzed to prove that the mechanism of the radial convergence of the absolute angular momentum proposed by Smith et al. (2009) can successfully explain the reintensification and spin down of NT2006 over land.

Abstract:A sequential quadratic programming method without using a penalty function or a filter was proposed. The algorithm computes the overall step in two phases. The first phase is to compute a feasibility step. The feasibility phase aims at reducing the infeasibility measure. The second phase, an optimality phase computes a trial point reducing a quadratic model of the objective function. The feasibility and optimality phases are independent in this algorithm; therefore, any method for reducing constraint violation can be used in the feasibility phase. Under mild conditions, the method can be proved to be globally convergent. Numerical results demonstrate the efficiency of this algorithm.

Abstract:For a given graph G, Ramsey number R(G) is the smallest integer N such that any red/blue edgecoloring of KN contains a red copy or a blue copy of G. Let broom Bk,m be a tree obtained by identifying the central vertex of a star K1,k with an endvertex of Pm. It is proven that R(Bk,2k-1)=4k-2 and R(Bk,4)=2k+3 for integer k>1.