Abstract:In the present paper, a method was proposed to represent the twophase, homogeneous random field. In the first place, the framework of twophase random field was put forward and the homogeneous and isotropic assumption was given as the premise of the work. Then, the stochastic harmonic function (SHF) representation for the Gaussian random field was provided as the intermedia for the twophase random field. With the SHF based random field, the Nataf’s transformation was applied to convert Gaussian random field into the target random field. The Hermite polynomials were used as the numerical solution for the bivariate Gaussian pdf involved in the Nataf’s transformation. Finally, several numerical examples were given to clarify the validity of stochastic harmonic function based twophase random field.

Abstract:The internal forces of underground structures in an earthquake are controlled by the seismic deformation of surrounding soils. Based on the forced displacement method for seismic design of underground structures, a novel seismic design method, named the integral forced displacement method, was proposed. The ground response deformation was applied to the finite element model of integral soil in this method to simulate seismic loading. Taking a subway station in Shanghai as an example, the implementation procedure and special features were introduced. By comparing with dynamic time history analysis results，the validity and accuracy of the proposed method was verified. The results show that the design concept of integral forced displacement method well agrees with the earthquake damage mechanism of underground structures, and the method is suitable for seismic analysis and design of underground structures in practice.

Abstract:To understand the relationship between the flow field characteristics and aerodynamics of the cable with the upper rivulet, the flow around and aerodynamic characteristics of a cable model with an upper rivulet were investigated using large eddy simulation (LES) in the subcritical regime. The results show that there exist three distinct flow regimes with the rivulet located at different positions. In the range of θu=0°~50°, the rivulet has little influence on the cable. In the range of θu=50°~70°, with the interferences of the upper rivulet, the upperside shear layer of the cable which is detached from the rivulet can reattach on the cable surface and form a single separation bubble at the upper side of the cable, which induces an asymmetrical pressure distribution on the cable surface. In the range of θu=70°~90°, the upperside shear layer detaches at the rivulet, which causes a lower negative pressure on the upperside surface compared to those of the lowerside of the cable. It is concluded that the appearance and disappearance of the single separation bubble are the underlying reasons for the occurrence of the rainwindinduced vibration (RWIV).

Abstract:A sheartype substructure shaking table testing (SSTT) method, which includes the substructure partition and the testing flowchart, was proposed using the unconditionally stable explicit ChenRicles (CR) new integration algorithm. The substructure method was numerically verified by deducing the equations of motion (EOMs) of the substructures. Two cases with different magnitudes of the frequency for the experimental substructure were considered. The results show that the stability and the accuracy of the substructure method can be guaranteed if the frequency of the experimental substructure is relatively small, and vice versa. Finally, the discrete control theory was applied to deduce the discrete closedloop transfer function of the block diagram for the substructure method. In addition, the locations of the poles for the transfer function was used to judge the stability of the discrete system so as to further demonstrate the findings from the numerical simulation.

Abstract:Two steel piles with an embedded depth of 6.47 m and diameters ranging from 0.9 m to 1.09 m were constructed under soft soil site conditions against toppling moment and shear forces by using the oneway singlecycle quickmaintain load method. The pile bending moments and the horizontal displacements of pile top were recorded for different load levels. The lateral bearing capacities with and without the soil stabilization were then compared and the accuracy of the rigidshortcolumn (RSC) method was evaluated. The test results show that the recorded bending moment quickly increases to the maximum at 0.06 to 0.15 times of the embedded depth, and then decreases along the pile depth. When the load is less than 0.23, the displacements decrease by 20% to 30%, which are lower than those before soil stabilization, indicating that the soil stabilization improves the lateral loadbearing capacities of the piles. However, the positive influence of soil stabilization is not present when the load level is larger than 0.6. The steel consumption of piles designed by using the RSC method is 37% more than what is practically needed, indicating that this design method could be improved.

Abstract:Based on uniaxial compressive dynamic mechanical experimental tests of confined recycled aggregate concrete (CRAC), the influence of strain rate effect on mechanical performance of CRAC was comprehensively investigated. The dynamic failure pattern and the experimental complete curves of uniaxial compressive stressstrain of RAC subjected to dynamic loading with different strain rates were analyzed. It is found that for the uniaxial CRAC curves of strainstrain relationship, at various strain rates, replacement ratios of recycled coarse aggregate (RCA) or volume stirrup ratios, the feature of the ascending branch is basically consistent. However, the descending branch exhibits some differences. With the increase of the strain rate or the replacement ratio of RCA, the descending branch changes in a steepening trend. However, with the increase of the volume stirrup ratio, the descending branch changes obviously in a flattening trend. Through regression analysis of experimental test data, models of the dynamic increase factor (DIF) for the compressive peak stress and the peak strain were proposed, respectively. With increasing amplitude of strain rate, the compressive peak stress and peak strain of CRAC increases. However, the increasing trend of DIF for the compressive peak strain is smaller than that of the compressive peak stress. The influence of strain rate on the initial elastic modulus of CRAC was also investigated, and the relationship between the initial elastic modulus and the strain rate was determined based on the experimental data. Furthermore, the model of the DIF of the initial elastic modulus of CRAC was established. It is concluded that the DIF of the initial elastic modulus of CRAC increases at dynamic loading with increasing amplitude of strain rate, however, the increasing trend is smaller than that of the compressive peak stress, as well as that of the compressive peak strain.

Abstract:This paper presents an experimental study on the moment resisting capacity and stiffness of the proposed prestressed bolted connection. Highstrength bolts with square tubes were used as fasteners in such connections. Two groups of experimental tests were conducted with Tshaped glulam beamtocolumn connections at monotonic and reversed cyclic loading. The failure mode, momentrotation curve, strength, stiffness and energy dissipation property of the prestressed bolted connections with square tubes were obtained and compared with those of traditional bolted connections. The results show that the initial rotational stiffness of prestressed bolted connection increases significantly as a result of the friction between steel tubes and steel plate at the friction stage, and the energy dissipation capacity of prestressed bolted connection is also improved.

Abstract:Sixteen specimens were tested under axial compression to investigate the effect of coldforming process on the behavior of stub columns. The main parameters varied in the tests were the widththickness ratio of steel tubes. The test results indicate that the shape of loaddisplacement curves depends mainly on the widththickness ratio of crosssections. When the widththickness ratio is relatively small, the axial load decreases slowly after the peak ponit of the curve and the total axial displacement is relatively large before failure. On the contrary, the effect of local buckling on the loaddisplacement curves is significant, which results in the sharp declining of curves after the peak point when the withthickness is rather large. Meanwhile, the calculation results of related standards considering the coldforming effects were compared with the experimental results. The comparison show that the formula for calculating the yielding strength of coldFormed thinWalled sections considering the coldforming effects in Chinese Technical Code of ColdFormed ThinWalled Steel Structures(GB500182002) is suitable for those coldformed thickwalled steel stubs with local buckling restrained.

Abstract:Based on the construction simulation analysis of Shanghai Tower, the preset deformation of suspend curtain wall support structure (CWSS) was studied, and additional internal forces in CWSS caused by the compression of super column were analyzed in detail. The analysis results shown that if the traditional methods of construction, that is, the ring beam is calibrated level by level, is used, the elevation of ring beam will be off the correct level after construction is completied. If the preraising of suspension point and preadjustment of the length of sag rod is adopted, the curtain wall service and geometry can be ensured. The compression of super column can lead to a relative displacement, which is large and complicated, between ring beams and floors of main structure. Construction simulation analysis should be conducted to determine the slide range of the sliding joint between CWSS and main structure under the compression of main structure. And the additional moment of radial strut caused by compression of super column is equivalent to 30% capacity of moment of radial strut. Its adverse effects on the CWSS cannot be ignored.

Abstract:Based on the measured data of typhoon Chanhom recorded atop Shanghai World Financial Center (494 m), the wind characteristics, such as mean wind speed, turbulence intensities, gust factors, and peak factors were analyzed. Turbulence integral scales were calculated by fitting a general spectral form to the measured wind velocity data. Wind speed spectra were compared with Von Karman spectra by using fitting parameters. It is shown that the correlation between the maximum 10 min mean wind speeds within 1 hr and the 1 hr mean wind speed, as well as that between the maximum 3 s mean wind speeds within 10 min and the 10 min mean wind speeds, both have a good linear relationship; the longitudinal and lateral gust factors are both linear with the turbulence intensities; the longitudinal and lateral turbulence integral scales increase as the mean wind speeds increase; and there exist some differences between the measured wind speed spectra and the Von Karman spectra.

Abstract:In this paper, a 2D bidirectional wavecurrent coupled model in Haitan Bay was set up based on the MIKE 21 SW wave module and FM current module. The effects of wave and current interactions were incorporated by extracting the radiation stresses from wave simulations into FM model, and extracting the water levels and velocities from flow simulations into SW model, respectively. The flow fields and wave fields in Haitan Bay under pure current and pure wave condition were simulated respectively, and calibrated by the field measured tidal flow and wave data. Then, the well validated models were employed to model the flow fields and wave fields under wavecurrent interaction. The results show that the wavecurrent interaction has a great influence on both flow velocity and wave height and the wave height significantly increases if the wave and current are in the opposite direction; the decay rate of wave height in the inshore area in both flood current and ebb current is in accordance with that in pure wave condition; the position for the wave height that begins to decrease in ebb current is obviously earlier than that in flood current; the radiation stress has a significant influence on the flow velocity in the wave breaking zone.

Abstract:Effects of air content and mineral admixtures on the flexural strength, frost resistance and deicerfrost scaling resistance of airport concrete were investigated in this paper. The results show that the frost resistance and deicerfrost scaling resistance of concrete are significantly improved, and its flexural strength is enhanced by the addition of the airentraining agent. The frost resistance and deicerfrost scaling resistance of dry concrete are much lower than those of normal concrete at a similar air content. 15% fly ash or slag is suggested to replace Portland cement in order to get a higher late strength growth. The data on the airbubble structure parameters of the concrete can explain these results well, and prove that the airbubble stability and airbubble structure of the dry concrete are obviously worse than those of the normal concrete.

Abstract:In order to investigate the applicability of constitutive model to unbound granular material (UGM) base asphalt pavement, strain tensor update algorithm and finite element program of UGM constitutive model were developed and applied to ABAQUS finite element software, and the calculated results were compared with the measured ones in the field. The results show that the calculated convergence modulus distribution of UGM is extremely nonuniform. The calculated bottom strain or stress or the maximum shear stress within the asphalt layer with Uzan model is bigger than the calculated ones with linear elastic or kθ UGM models. The calculated bottom strain of asphalt layer with the Uzan UGM model is the closest with measured value by comparing with the measurements in the field.

Abstract:In order to study the wetting failure mode and mechanism of widening subgrade in selfcollapsible loess areas, the rain system and deformation field test system were installed in geotechnical centrifuge of Chang’an University. The centrifugal modal test consistent with the actual stress was conducted using the undisturbed collapsible loess. The settlement law of widening roadbed flooded by rainfall was studied and the damage mode of widening roadbed was analyzed according to the test results. The test results show that the foundation under widening roadbed producea a large settlement under the action of gravity load whose largest value appears in widening roadbed centroid place, resulting in a poor coordination deformation between new and old roadbed. The local instability of the foundation under widening roadbed caused by continuous rainfall poses a great threat to the safety of the upper widening roadbed. The formation of widening roadbed is a gradual process: First is the emergence of the collapsible caves. Next, appear the cracks in toe. Fanally comes the large deformation caused by the wetting toes which gives rise to the damage of pavement even landslide.

Abstract:The gas network can be abstracted as network model by social network analysis（SNA）.Taking the gas pipeline of the central city of Jinzhong as an example, this paper constructed the current network and planning network on Pajek. The network structure evaluation system was constructed including the topology structure, operation status and key facilities. Eight indexes including network density were calculated. The results show that the current gas network has a better operation while the planning has a better topology structure. The strategy for the network structure optimization and physical facility maintenance was proposed.

Abstract:The heat transfer characteristics of allwelded plate economizer in different structure parameters and flue gas velocities were numerically simulated using Fluent and experimentally verified. The results show that the whole welding type plate heat exchanger whose major axis of the ellipse is 30 mm has the highest heat transfer coefficient, when the ratio of the shortlong shaft is 0.6, the flow path in interboard spacing of flue gas is controlled at 15 mm, and the rate of flue gas flowing is in 8 m?s-1. The highest heat transfer coefficient is about 50 W?(m2?K)-1.

Abstract:The software FLUENT was applied on a Φ200 mm×2 m furnace to study the influence of jet momentum ratio and jet spacing on the flow field and combustion characteristics at O2/CO2 atmosphere. The results show that when the jet momentum ratio varies from 28 to 66, the peak of flue gas inner recirculation rate increases and then decreases, and the overall level of inner recirculation rate in the mixing zone is the largest when the jet momentum ratio is 48. When the jet spacing gradually increases, the recirculation zone on xz plane shifts downstream. Besides, the region where the concentration of oxygen volume is higher than 10% narrows, the temperature peak decreases slightly. However, the jet spacing must maintain a proper value. When the jet spacing is 75 mm, the recirculation zone on the xz plane narrows significantly, and the oxygen concentration in the reaction zone rises again, and, as a result, the temperature peak increases. The temperature peak is the highest (about 2 200 K) under coaxial jet condition, the max temperature increase is lower than the ignition temperature(790 K) only when the jet spacing is 60mm, indicating that the oxyMILD combustion state can be established.

Abstract:With the rapid development of highspeed railway and urban rail transit, the significance of security is of unprecedented significance. Track regularity is of crucial importance to highspeed railway operation safety. This paper proposed a method to detect track static regularities based on a laser tracker. A track static regularity detecting system was built based on the laser tracker integrated displacement sensor, tilt sensor and communication sensors and their platform setup. Software development was aimed at verifying the methods of track static regularity detecting and data processing. In order to verify the detecting and data processing method of track static regularity, experiments were conducted at a part of the Shanghai metro line 13 at Natural Museum Station. The SGJTCECⅠpassenger dedicated line track geometric condition detection device was used for comparative analysis. The feasibility and high accuracy of the track static regularity detecting method and data processing method are verified by using the SGJTCECⅠpassenger dedicated line track geometric condition detection device.

Abstract:An exterior autocalibration method without relying on ground control points (GCPs) was proposed based on the analysis of the errors of exterior orientation elements affecting positioning accuracy. The character that the positioning error caused by pitch angle and roll angle is equal in value but opposite in sign is used as the foundation of the method. Moreover, the proposed method can be verified by the simulation data. Experimental results show that errors of exterior orientation elements can be compensated and geometric accuracy can be effectively improved without relying on GCPs.

Abstract:Focused on the institutional transition and scheme evolution of mega infrastructure investment and finance, the phases of relevant institution were analyzed. A governmentmarket dual evolutionary game model on mega infrastructure investment and finance was built. Then, the decisionmaking level of the government, investment willingness and investment amount, the yield and risk of mega infrastructure investment on the evolutionary stable strategy of both agents and their mixed strategy combining system simulation technology were studied. Finally, the feedback mechanism between policy, institution, decisionmaking level of government and investment willingness were discovered. The two parameters together with the investment ability of the government, the yield and risk of mega infrastructure investment have a great impact on the investment and finance scheme. The evolution path is determined by the institution transition route.

Abstract:Change orders are the main cause of over budget cost. A project delivery mode called IPD (Integrated Project Delivery) can eliminate change orders in foreign construction projects, because its internal incentive mechanism based on principles of IPD can prompt contractors participating in the design phase to assist designers in optimizing design actively. In previous study, an IPDbased qualitative incentive mechanism adapting the situation of construction projects in China was established to eliminate change orders. First, this paper summarized the qualitative incentive mechanism. Then, by analyzing the characteristics of change orders that would be eliminated by designers and contractors in China, established a quantitative incentive mechanism based on the qualitative one. Finally, it verified the effectiveness of the quantitative incentive mechanism with the financial data of actual projects.

Abstract:This paper presented a theoretical model of construction enterprise developing serviceoriented building model and ten key elements to study the mechanism of construction enterprise innovation and development affected by serviceoriented building model. Using the intuitionistic fuzzy number of dynamic property decision analysis method and the correlation analysis method, the statistical survey data were empirically analyzed, which revealed the functions and mutual relations on the value chain of construction enterprise development of serviceoriented building factor, and provided the solution to improving the integral level of building service business of construction enterprises.

Abstract:The improved failure mode and effects analysis (FMEA) based on the fuzzy set theory and gray relational theory was proposed for the solution to effective quantization questions of risk analysis in bidding strategy. First of all, combining with the fuzzy set theory, the fuzzy linguistic terminology set of the failure mode and corresponding fuzzy numbers were established, and the different failure modes were evaluated by the FMEA team. Next, the relevance ratio of different failure modes was calculated using the gray relation theory and the risk order of failure modes was confirmed by sorting. Risk analysis cases of biding strategy illustrate the usability and effectiveness of the proposed approad.