Abstract:Strong motion records with high recording qualities and basic site data were sought out from seismic records in various countries and regions, from which some typical long-period seismic waves were selected for analysis. Then, both the mean acceleration response spectrum and the fitted response spectrum based on long-period and general seismic records on different sites were analyzed and compared. After that, the fitted spectrum of seismic waves on soft sites was taken as the target, and its power spectrum density was iteratively calculated. The characteristics of acceleration power spectrum densities based on long-period seismic records were also analyzed. On this basis, with a super-long-span cable-stayed bridge as the background by applying ANSYS software to establish three-dimensional finite element model of the bridge structure, using power spectrum densities based on long-period seismic records and general seismic records as input, and utilizing the direct displacement pseudo-excitation method, the travelling wave effect of the super-long-span cable-stayed bridge under different apparent wave velocities was studied. The results have shown that the predominant frequency of power spectrum densities based on long-period seismic records is apparently lower than those based on general seismic records; the displacement response power spectrum values at the left tower top, the right tower top and the mid-deck under long-period seismic power spectrums are significantly larger than those under general seismic power spectrums, and the distribution of the displacement response power spectrum at tower tops is bimodality; and in this case, the travelling wave effect reduces the displacement and bending response values of the bridge structure.

Abstract:The seismic collapse-resistant capacity of the three-dimensional (3D) parking structure with alternation story-height truss lateral-load-resisting system was evaluated by IDA-based seismic fragility analysis method. The structural collapse process and mechanism under earthquake were analyzed. The seismic collapse-resistant capacities of the structure under one-directional and bi-directional earthquakes were compared. And the comparison of the seismic collapse-resistant capacities and collapse margin ratios of the structures with different floors was carried out. The result has shown that the seismic collapse-resistant performance of this kind of 3D parking structure is very good, and the first storey is the weak storey. The collapse probability increases with the increase of the storey count of the structure, and then the seismic performance becomes weak. However, the collapse margin ratio of the structure does not always decrease with the increase of the storey count of the structure. It is recommended that the provision of the height-width ratio in the current design code of building structure can be broken in the design of this kind of 3D parking structure.

Abstract:To comprehensivly evaluate the seismic behavior of pre-cast concrete shear walls with vertical reinforcement lapping in pore-forming on steel plate connected in horizontal joints, fabricated and cast-in-place concrete shear wall with full scale specimens were tested and compared through quasi-static test. The test results showed that the ultimate failure pattern of the vertical connection in pore-forming on steel plate and the cast-in-place specimen was basicly the same, initial cracks appeared in different positions,the hysteresis curve of the specimen was full, the trend of the skeleton curve was basically the same, the capacity of energy dissipation was also similar; the ultimate displacement angle of each specimen was from 1/55 to 1/43, the displacement ductility factor was from 4 to 5, which met the ductility requirements; and the load carrying capacity of vertical reinforcement lapping in pore-forming on steel plate was lower than that of the cast-in-place specimens. Pre-cast concrete shear wall with reasonable horizontal joints can achieve considerable carrying capacity, ductility and seismic energy dissipation capacity with the cast-in-place specimens.

Abstract:According to the large-scale undersea immersed tunnel of the Hong Kong-Zhuhai-Macao Bridge, and based on the actual site soil geological distribution, three-dimensional refinement FEM models were built considering the siltation above the tunnel with and without siltation. The nonlinear characteristic of flexible joints, the nonlinear contact effect between the soil and tunnel, and the nonlinear behaviour of soil material were all taken into account in the calculation model. With uniform excitation and travelling wave excitation input directly on the bedrock surface, the earthquake response analysis of soil-immersed tunnel was conducted with the dynamic explicit algorithm. Numerical results have shown that the existing siltation soil above the tunnel reduces the natural frequency of soil-immersed tunnel system and increases the seismic response of tunnel. The excitation mode and excitation direction of seismic wave also have certain influence on the relative deformation of flexible joints and the internal force response of tunnel, which can not be ignored.

Abstract:A new method of reliability design optimization using the evidence theory was proposed. Evidence theory was presented as an alternative to the classical probability theory to handle the imprecise data situation. The plausibility measure Pl(F) based on evidence theory, with Pl(F)

Abstract:To address the knowledge gaps of the cyclic stress-strain model of FRP-confined concrete, this paper presented the experimental results of CFRP-confined plain and RC square columns under monotonic and cyclic axial compression. The specimens were divided into two groups on the basis of size. The width of the cross section and the height of the total column were 305 mm, 915 mm and 204 mm, 612 mm for the two groups, respectively. Test results showed that the stress-strain curves of the CFRP-confined larger columns exhibited a localized strain-softening behavior, in which the confinement of CFRP wrap was moderately-confined and significantly influenced by size effect. Moreover, the ultimate compression strain, unloading curves and plastic strain were remarkably influenced by hoops. Based on the test data, a cyclic axial stress-strain model for FRP-confined square concrete columns was proposed. The proposed cyclic axial stress-strain model consists of three main components, namely (i) a monotonic stress-strain model to describe the envelope curve, (ii) a polynomial expression for the unloading curve, and (iii) a straight line for the reloading path. The influences of internal steel reinforcements, size effect and as well as the number of layers of CFRP wrap were considered. The good agreement between the predictions of the proposed model and the test results demonstrates the capability and accuracy of the proposed model.

Abstract:The formula for the bending capacity of aluminum alloy gusset joints loaded by out-plane bending moment was proposed theoretically. The experiments on four aluminum alloy gusset joints, three loaded by out-plane bending moment and one loaded by shear force together with out-plane bending moment, were conducted. The possible failure modes of the gusset joints were presented, which are as follows: member bending failure, joint plate block shear rapture failure and joint plate bucking failure. Based on the test results, the range of k1, which represents the reduction of the bending resistance caused by prying action, was proposed, and the formula for bending capacity was verified. Correspondingly, 4 finite element models were established by finite element software ABAQUS as a supplement of the experimental studies.

Abstract:In order to obtain the interface friction characteristics between reinforcement and coal gangue mixed with different qualities of soli, large-shear tests were carried out. The test used gabion mesh galvanized and covered with plastics. The filler was coal gangue mixed with different qualities of soil and prepared with the optimum moisture content. The samples controlled the compaction of 94%. The results showed that the relationship between shear stress and displacement on the interface friction and coal gangue and reinforcement was nonlinear, and the shear stress on the interface friction increased with the increase of normal stress.The parameters of the interface friction strength changed regularly with the increase in the amount of soil when the mixed soil was less than 20%. When the mixed soil increased, the interface cohesion decreased first and then increased, but the interface friction angle first increased and then decreased. The strength parameters of the coal gangue mixed with reinforcement conformed to the theoretical formual Mohr. The formula not only reflects the cohension between coal gangue and reinforcement, but also has a better correlation coefficient.

Abstract:Through the experimental research on the compressive strength and setting time of inorganic cementitious materials under different mix proportion, a good mix proportion with better strength and condensation rate was obtained. In this mix proportion, the strength of test block for three days was 43.7 MPa, reaching 69.0% of the compressive strength of 28 days, and the setting time was less than 5 min with good performance in rapid solidificatio and high strength. Two different types of inorganic glass plastic bolt were made on the rapid solidification and high strength performance, and the drawing ultimate bearing capacity under different bar diameter,anchorage depth, anchorage angle and time factors was investigated through the anchorage drawing experiment. Based on the experimental phenomena, typical failure modes were summarized and relative anchorage length formula with data regression was put forward on the basis of ultimate bearing capacity drawing results.

Abstract:To address the problem of the thick pavement structure and the damage of the bridge deck, this paper analysed the mechanical properties of the bridge deck pavement material, proposed a kind of thin epoxy overlay structure and developed elastic epoxy resin adhesive. Through the selection and formulation optimization of flexibilizer, diluent and curing agent, a kind of elastic epoxy resin adhesive with good performance was obtained. Tensile testing has shown that the tensile strength of the elastic adhesive is 21 MPa, and the elongation is 50%. Meanwhile, its bond strength is up to 2.5 MPa and the thermal compatibility is appropriate. The results have also shown that the comprehensive performance of the elastic epoxy resin adhesive is excellent, and it can be applied to bridge deck pavement engineering.

Abstract:A numerical experiment was adopted to analyze the effects of wind speed, initial wind angle, elevation difference and ice thickness on the longitudinal unbalance tension of transmission tower. Harmony-superposition method was used to simulate the fluctuating wind speed time series acting on the transmission tower line, and the law of unbalance tension was derived by changing elevation difference and ice thickness.The results have shown that, in some cases, the value of the longitudinal unbalance tension of the tower in existing electricity industry standard is smaller. Based on computational analysis, the theoretical formula of the longitudinal unbalance tension of towers subjected to wind and snow simultaneously was proposed. The errors of the formula are within ± 6% compared with numerical simulation. It has preferable accuracy.

Abstract:Based on the pressure measurement tests of wind tunnel experiments, this paper discussed the impacts of different types of terrain and surrounding interference for peak wind pressure on the high-rise buildings. The results show that different types of terrain have a great impact on the peak pressures of high-rise buildings. When the surrounding environment of high-rise buildings remains unchanged, the peak pressure coefficients of different types of terrain are followed by B, C and D from large to small in most cases. The peak pressure impact of high-rise buildings is not only related to the relative position of the surrounding buildings, but also to the type of terrain a high-rise building at the time. For example, if the south facade is the wind surface and interfers buildings E and F located diagonally in front of the south facade, it performs a shielding effect. In this case, the vast majority of the peak pressure coefficients obtained in the terrain category of B, C and D are reduced differently in the vast majority of test points with a maximum decrease of 43%, 37% and 46% respectively.

Abstract:Based on the wind turbine tower-blade coupled model, the modified blade element momentum was used to simulate the aerodynamic loads of wind turbine model, which considers the rotational effect caused by blades and blade-tower interaction. The wind turbine tower-blade coupled model considering the centrifugal force from rotational blades was established in finite element method, and the time-domain analysis of wind-induced responses of wind turbine tower-blade coupled model was carried out. Then, the dynamic response characteristics of the wind turbine system under stochastic wind loads were discussed on the basis of the calculated results and through the contrast with the wind-induced responses of a tower without the blades. It is proposed that the wind turbine tower-blade coupled model should be adopted in wind resisting design.

Abstract:This paper investigated the effect of rear end deflectors on the near wake and aerodynamic drag of an Ahmed model with 25° slant angle. Drag reduction was compared for deflectors mounted on the two side faces and on the upper edge of the rear slant. The width of deflectors is 5mm, 10mm and 15 mm, respectively. The model scale is 1∶2, and the Reynolds number based oncoming flow velocity and model length is 8.7×105. The results have revealed that there is a pair of organized trailing vortices in the wake, which are accompanied by strong downwash flow. There is a D-shape flow separation zone on the slant face. Deflectors with a width of 5 mm at the two sides of the slant have negligible effect on the near wake, and slightly increase the aerodynamic drag by about 2.1%. On the other hand, all tested horizontal deflectors at the top edge of the slant and deflectors with a width of 10 mm and 15 mm at both sides of the slant considerably weaken the trailing vortices. The horizontal deflectors avoid flow re-attachment on the slant and suppress the D-shape separation zone, corresponding to the maximum drag reduction rate of 11.8%, which is higher than that of the deflectors on both sides of the slant.

Abstract:The manufacturing stage, transport stage and on-site construction stage of building materials consume large amount of energy. Based on the three stages, the calculation method for energy and exergy consumption was presented, and the concept of exergy-energy ratio was proposed to evaluate the sustainability of building energy use. A case of a research and development center located in Hunan was analyzed. The results have shown that the energy consumption of building envelope construction mainly comes from the manufacturing stage of building materials. Unit building area energy consumed by concrete and steel accounted respectively for about 44% and 41% of the total energy consumption of building materials production. Unit building area exergy consumed by concrete and steel accounted respectively for about 38% and 48% of the total exergy consumption of building materials production. From the perspective of exergy-energy ratio, the maximum value is steel, 0.92; and the minimum is cement, 0.59. The exergy-energy ratio of building envelope construction is 0.79. The results can provide reference for the research of energy consumption resulting from “uncompleted building”. The exergy assessment method presented can be applied to other similar buildings, and can provide reference for sustainable building construction.

Abstract:A 1/10 scale model for the ventilation system of the underground powerhouse of Ganhe Pumping Station was established on the basis of numerical simulation and similarity theory to study the feasibility of the pumping station's ventilation system . The model tests contained 9 different working conditions, such as different seasons, different supply air temperatures and different numbers of operating units. The interior parameters of all regions in the underground powerhouse were tested, and the test data were analyzed. Experiment results have shown that the highest and the average interior temperature is 29.46 ℃ and 27.72 ℃ respectively in summer when the supply air temperature reaches 24.5 ℃. The scheme for the ventilation system meets the requirements of relevant standards. The indoor temperature is lower in transition seasons and in partial loading condition. Therefore, VAV system can be used in the ventilation system in order to achieve further energy saving.

Abstract:In order to study the regional capital liquidity, Bayesian panel smooth transition regression models were established to address uncertain risk of parameters estimation in PSTR models. Based on the analysis of model statistic structure and the selection of parameters prior, the Metropolis-Hasting within Gibbs sampling method was utilized to estimate model parameters, avoiding the convergent problem when using the nonlinear least square method in PSTR model. The empirical research applies Bayesian PSTR to analyse the panel data of investment and saving in Chinese provinces. The research outcome indicates that the iteration trace of parameters is convergent, and the Metropolis-Hasting within Gibbs sampling method estimates model parameters accurately, showing the effectiveness of Bayesian PSTR model approach.

Abstract:To address the problems in the evaluation of science and technology awards, this paper proposed an improved CRITIC method, which was modified by coefficient of standard deviation to carry on the dynamic empowerment. And combined with cloud model, the method used reverse cloud generator to construct a fuzzy evaluation matrix and used the virtual cloud to calculate the expectation entropy and hyper entropy of evaluated project to get and sort the evaluation results. This method can consider the fuzziness and the randomness of expert score in the evaluation of science and technology awards, and realize the conversion between the qualitative linguistic and the quantitative numerical value, thus reducing the interference of expert subjective factors and making the results more accurate and objective.