Abstract:Low-cycle reversed loading test and finite element analysis of a welded connection specimen between square steel tube column and H shape steel beam were conducted. The calibrated micromechanical fracture criteria degraded significant plastic strain (DSPS) model and the cyclic void growth model (CVGM) were used to predict extremely low cycle fatigue fracture initiation for this specimen and the cyclic tests of two side column connection specimens with welded flanges and bolted webs conducted by others. Compared with test results, the predicted fracture location, load cycle number corresponding to fracture, fracture load and displacement have high accuracy. Subsequently, the sensitiveness analyses of damage degradation parameters in micromechanical fracture criteria to the predicted results of fracture were conducted. The results show that the predicted results of fracture are insensitive to the values of damage degradation parameters. Therefore, it is feasible to use the micromechanical fracture criteria to predict extremely low cycle fatigue fracture initiation for steel structure connections under cyclic loading.

Abstract:The residual crack extension resistance curves (KR(Δa) curves) of post fire concrete, associated with cohesive force distribution on fictitious crack zone of complete fracture process, were obtained by analytical method and weight function method. Wedge splitting tests of 10 groups at temperatures from 20 °C to 600 °C were made. The cohesive force distribution corresponding to four different crack propagation stages was determined according to Petersson and CEB FIP Model 1990 bi linear softening traction separation law. It is found that the residual fracture toughness increases with the increasing of the crack length, whereas, the KR(Δa) curves decrease with the increasing temperatures for the thermal damage induced. KR(Δa) curves calculated by analytical and weight function method have a good coincidence. The softening curves have an obvious influence on the shape of KR(Δa) curves.

Abstract:A theory of best control parameters (BCP) is developed based on Chopra’s approach to tackle the problem. Theoretical derivation and selection principle of BCP are also presented. A modal pushover analysis(MPA) of a pile foundation from Shanghai Changjiang Bridge is then conducted by using the developed BCP approach. First mode pushover analysis (Po 1) and nonlinear time history analysis (THA) of the pile foundation system are also conducted as the reference. The following conclusions are drawn through a comparative study: the BCP selection method efficiently resolves the reversal phenomenon in MPA of the pile foundation system; the displacement demands estimated by MPA with the selected BCP are closer to the results of THA, and much better than those provided by Po 1.

Abstract:Based on the current research for ductility capacity of single column pier, a simplified calculation method of elastic plastic displacement capacity for double column bent was obtained by analyzing the effects of dynamic axial force and plastic hinge mechanism on the elastic plastic displacement capacity of double column bent. With the proposed simplified calculation method of double column bent, the obtained yield tip pier displacement was larger than that calculated by pushover analysis and the accuracy was within the acceptable range. When the axial compression ratio was within 5%~20% and the slenderness ratio was within 5~10, the calculated tip pier collapse displacement was within 20%. With the increasing of the slenderness ratio and the decreasing of axial compression ratio, the tip pier collapse displacement by the proposed simplified calculation method was less than that by pushover, therefore, the proposed simplified calculation method was safe.

Abstract:Combined with the construction example, the 3D FEM simulation with a consideration of the soil disturbance during construction was proposed to predict the soil movements induced by the new pneumatic caisson method construction. The calculated soil movements were examined and verified by the field measurements. The results indicate that the maximum surface settlement exists in the caisson wall edges. During the caisson sinking progresses, the settlement increases and the influence zone on the ground surface is widened gradually. The subsurface horizontal displacements are small and vary along depths. The shallow soils tend to move towards the caisson and the maximum displacement occur to the surface, whereas the deep soils tend to move away from the caisson. Finally, the effects of several parameters which might affect the ground deformation were investigated. It can be concluded that the surface settlements close to the caisson walls are reduced significantly because of the compacted zone existence.

Abstract:Dynamic triaxial test of Huashan granite was conducted to analyze the relationship between the strain rate and the granite compressive strength, the elastic modulus and Poisson’s ratio with different confining pressures. Test results show that with the same confining pressure, the compressive strength increases with the strain rate, but there are no apparent changes in the elastic modulus and the Poisson’s ratio of the granite. The compressive strength also becomes larger with increasing confining pressure at the same strain rate, while the elastic modulus and Poisson’s ratio changes little. Based on the above test results, Mohr Coulomb and Hoek Brown criteria were adopted to quantitatively analyze the relationship among compressive strength, strain rate and confining pressure. As for the former, the change of strength is primarily due to the variation of cohesion with strain rate. Assessment of the Hoek Brown criterion indicates that the uniaxial compressive strength increases with strain rate, but the parameter m changes very little.

Abstract:Based on the rigid model tunnel test and nonlinear wind induced response calculation method, the vibration frequencies of initial form finding state and static equilibrium state, the upward and downward maximum displacement responses under wind load of two saddle tensioned membrane structures are analyzed to study the simplification of similarity parameters. According to the results, it is proposed that, for the tensioned membrane structures without diagonal height difference, similarity requirement of Froude number should be less than λ2V/λL=10/4; for those with diagonal height difference, similarity requirement of Froude number should be less than λ2V/λL=20/4; the quality coefficient should be controlled in the range of 0.8~1.2; and the elastic modulus coefficient should be in the range of 0.5~1.5.

Abstract:The mechanical behaviour of a damaged strand suspender with symmetric broken wires is studied. Based on the compatibility condition that the total suspender elongation before and after wire breaks must be the same because it is “locked in” by the anchorages, the stress redistribution of a damaged suspender with symmetric broken wires is identified. Expressions are derived for the wire strains, the affected length, and the remaining prestressing fraction. Results show that forces of the broken and unbroken wires of the suspender are not equal within the affected length, especially, at the break, but equal beyond the length. The strains of unbroken wires within the affected length are not uniform. The maximum strains occur to the two unbroken wires adjacent to the broken wires and the minimum strains at the unbroken wires opposed to the broken wires. The strain of the broken wire is zero at the wire break and increases exponentially with distance from the break. The strain of the unbroken wires is a maximum at the wire break and decreases exponentially with distance from the break. Within the affected length, the remaining prestress fraction approaches a lower limit, which is equivalent to or less than the loss of the cross sectional area of the suspender. Meanwhile, the stress redistribution of a damaged suspender is significantly affected by contact forces between the sheathing and outer wires and frictions between the broken wires and the king wires.

Abstract:A computer simulation was carried out to study the fire safety distance between color steel polystyrene sandwich panel houses based on the existing experimental data. The comparison between the simulation and experimental results shows that, for the worst case, the average relative error of the maximum heat radiation intensity is 8.77%，and the maximum temperature is 7.71%, which verifies the simulation method. A subsequent simulation study focused on the effect of different wind speeds to the development of panel house fire based on the former mode，the fire safety distance formulas were obtained by the regression analysis. With good correlations, the formulas can be promoted and they can be further used as a reference for the design and the calculation of the fire safety distance between sandwich panel houses.

Abstract:This paper presents a naive Bayesian classifier based algorithm for freeway non recurrent traffic incident detection to enhance the accuracy and learning ability of intelligent traffic incident detection algorithm. The traffic wave theory is employed to establish a conceptual characteristic model of traffic incident, continuous characteristic variables are transferred into discrete characteristic variables via sub discretization, and the naive bayesian based traffic incident classifier is designed by regarding traffic incident detection as “0 1” classification problems. An experiment is carried on a section of a typical freeway, and the performance of the presented model and algorithm is validated via VISSIM simulation. Extensive simulation results show that the algorithm in freeway traffic incident detection system is of high accuracy and strong robustness even if the traffic volumes increase.

Abstract:An excess commuting model was established by taking income difference into consideration. Optimal spatial distribution model endogenously determine the number of additional workers and jobs. A case study of Mianyang City shows the best situation of job housing balance reaches when jobs addition is up to 14%, and the future jobs housing balancing policy proposal in Mianyang City for each income level is put forward based on this model.

Abstract:Effluent from secondary biological process for papermaking wastewater was employed as the model pollutants. Under the optimum conditions of the initial pH: 4, pyrite adding dosage: 1 g·L-1, H2O2 adding dosage: 50.0 mg·L-1, and the oxidation reaction time: 1 h, chemical oxygen demand (COD) of wastewater can decrease from 136.0 mg·L-1 to 44.8 mg·L-1. The pyrite is found to be active to promote Fenton like reaction with low cost due to high utilization efficiency of H2O2, furthermore, catalyst can be easily recovered from wastewater and reused.

Abstract:Elemental analysis method and Fourier transform infrared spectroscopy method were applied to the investigation of the effect of wood biochar on carbon loss and nitrogen loss of sewage sludge. Wood biochar was added on four levels, i.e., 0, 10%, 20%, and 30% of sewage sludge fresh weight. The results show that with the increasing of the wood biochar addition, the carbon content of sludge decreases significantly. Carbon loss is 18.3%~27.8% higher than the control. However, nitrogen loss is 10.3%~17.2% higher than the control. The reduction of polysaccharides, protein and aliphatic components, and a relative increase of aromatic components and compost maturity are proved by increasing wood biochar addition.

Abstract:Working process of an internal combustion Rankine cycle (ICRC) is studied based on bench tests of a prototype engine. A minture of O2 and CO2 is ased used to simulate eshaust gas recirculation(EGR) to control the combastion rate, and effect of injection phase on the combustion and emission characteristics is studied. Results show that water with injection temperature of 160℃ can not only control the reaction rate, but also can expand the area of the P V diagram through vaporization. As a result, the thermo efficiency increases by 6.3%. Injection phase does not affect the thermo efficiency obviously, however, earlier injection timing can increase HC emissions by 40%.

Abstract:Performance response tests of diffusion burner on the burner flame tube and heat transfer within industrial furnace were carried out by means of adjusting the proportion of dimethyl ether (DME) in natural gas. Results show that DME mixtures can give similar thermal efficiency in comparison with natural gas, which implies that the mixture has an acceptable interchangeability with natural gas. In addition, pollutant emissions when fueled with DME mixture were found to be consistent with those under natural gas. Particularly NOx remained quite low. It was recommended that DME percentage should be controlled within 10%~30% for the sake of economic feasibility.

Abstract:A new method for the researching of the theoretical digging forces and its regularities of distribution was presented based on the workspace and digging points. The spatial position of digging points was calculated first, the digging gestures corresponding to each digging point were solved by the inverse kinematics principle. The theoretical digging forces of each digging gesture were calculated according to the relevant limit equations. A case study of a 36 t backhoe hydraulic excavator proved the hypothesis that the theoretical digging forces, corresponding to two adjacent digging points or two similar digging gestures, be similar. The calculation results show that the theoretical digging forces obtained by the new approach are improved obviously (>20.2%). The experimental result proves that the new approach reflects the maximum digging force of the backhoe hydraulic excavator more accurately at the given digging point.

Abstract:A method, global navigation satellite system(GNSS), is proposed for detecting velocity and amplitude changes based on the principal of binary tree for searching the most possible change epochs and testing the velocity and amplitude changes. Then the change epochs are tested by F test statistics. The proposed method verified with simulation data is applied to the analysis of the vertical coordinate time series of 5 base stations in crustal movement observation network of China. The results show that the proposed method has the higher fitting accuracy and the better reflection of the observation data.

Abstract:An automatic method for detecting and interpreting bridges over water in TerraSARX imagery is proposed. Two kinds of image textures including the Gabor features and gray level co occurrence matrix statistics are employed to segment the image in multiple scales and obtain the regions of interest (ROIs) of bridge. Line segment detector is used to estimate the direction of bridge. For each ROI, five key parameters of a bridge are estimated based on the imaging model of radar, including angle, width, elevation over water and thickness of body. Experiment results with TerraSARX image indicate that the method is effective.

Abstract:A modified iterative closest point(ICP) image registration algorithm based on spatial structure constraint is proposed to overcome the matching ambiguity of remote sensing image registration caused by outliers. This algorithm combines the similarities of spatial structure and feature to determine matching matrix of feature points, among which the similarity of feature is achieved by a local feature descriptor while the similarity of spatial structure is calculated by spatial coordinates of feature points. Different to current structure based algorithms, the similarity of spatial structure contains not only spatial distance of corresponding feature points but distance of neighboring ones. And in matching process, the matching pairs are determined by a bidirectional matching criterion from the view of reference and sensed images. Experiments on real remote sensing images of different characteristics show that this algorithm can enhance registration accuracy.

Abstract:Aimed at the matching problem for color images obtained by vehicle based mobile mapping system, an improved algorithm is proposed based on speeded up robust features(SURF) algorithm, which is robust in rotation and resizing. A dimension incremented color SURF algorithm based on Gaussian color model is proposed. RGB color model is transformed to Gaussian color model firstly, then the new SURF method is employed for matching experiment, which is improved by additional 48 dimentional colour features vectors. At last, the epiplor constraint is applied to the elimination of false matches. The experimental results show that the proposed algorithm performs favorably on matching points numbers, matching accuracy, and distribution uniformity of matching points, although a slightly more calculation is needed in comparison with the original SURF algorithm. It can meet the matching demand of mobile mapping system (MMS).

Abstract:The clay minerals of sediments from 9 wells in the northern South China Sea during the period from Oligocene to Miocene. were systemically analyzed based on sedimentary mineral analytical methods, Results show these clay minerals assemblage changes regulary with time and space. Illite smectite transition depth decreases from north to south, which is similar to the increasing trend of geothermal gradients. This illite smectite transition pattern reflects the thinning of the oceanic continental transitional crust in the northern South China Sea, and the uplifting of Moho surface, and the increasing of thermal flow index. The study of the relationship between clay mineral assemblage evolution and the trend of thermal flow change can help to forecast regional temperature field change law and understand thickness change of the oceanic continental transitional crust in the northern South China Sea.

Abstract:The lithology and distribution characteristics of the basement in Lishui Jiaojiang Cenozoic Sag were studied according to 2D seismic profiles and borehole data. As a result, metamorphic, granite, volcanic, sedimentary and volcanic sedimentary interbedded rocks basement units were qualitatively differentiated. The metamorphic rocks basement generally surrounds the central parts of the West Lishui Sub sag and Jiaojiang Sag with discontinuous, low frequency and moderate to weak amplitude seismic reflectors. However, in the northeast regions of the Lishui and Jiaojiang sags dominantly site the granite and volcanic rocks basement, in which the former appears to be mounded geometries with chaotic and weak amplitude internal reflections, whereas the latter represents a good stratification with moderate to continuous, low frequency and strong amplitude reflectors. Besides, the sedimentary rocks basement scattersl mainly in the Lishui Sag with moderate to continuous and strong amplitude reflectors, whereas the volcanic sedimentary interbedded rocks basement largely covers the central area of the Lishui Jiaojiang Sag with the continuity, frequency and amplitude varying violently in spatial.

Abstract:The conditional Monte Carlo method was constructed for pricing European options under stochastic volatility model, and then an efficient control variate was presented based on the Martingale representation theorem. Numerical tests show that conditional Monte Carlo simulations based on the martingale control variate method can reduce simulation error. Moreover the dependence of the efficiency of simulation on model parameters is not sensitive.

Abstract:The government replacement subsidy promotes product upgrading and destroys the profits distribution pattern of closed loop supply chain. The members’ profits distribution models in the closed loop supply chain in the non subsidy policy and in the replacement policy are set up by the game theory based on game theory in the home appliances replacement background. The results show that the replacement subsidy can promote the product sales volume, waste product recovering volume and the members of closed loop supply chain profits and reduce the costs of waste products collection activities; the government subsidy coefficient can effectively adjust the members’ profits distribution in the closed loop supply chain; the average of the government subsidy, government subsidy coefficient, limits of government subsidy can affect the subsidy influence significantly.

Abstract:Social and environmental benefits are discussed in terms of underground space services and a quantitative evaluation model for the benefit of urban underground space development is proposed through “with and without comparison method” and “aboveground and underground comparison method”. The research results show that the role of urban underground space development in promoting the development of the city is significant, and the land conservation benefits account for the largest proportion of total benefit, followed by saving time benefits. In addition, the spillover effect of underground space development, such as the conservation of land efficiency, air pollution reduction, noise pollution reduction and other benefits, can be internalized through tax, which can act as financing means and decision making basis for the public underground space development.