The objective of this study was to discuss the distribution features of dynamic deflection basins of distressed asphalt pavements using the dynamic finite element method. Based on the results obtained by systematic analysis, the criteria used to filter the effective data of falling weight deflectometer (FWD) deflection basins were presented and also verified by in-situ project study. The results demonstrate that the crack width of 0.2 mm is a critical value to determine the existence of contact behavior between crack contact surfaces. The distribution characteristics of dynamic deflection basins display a tremendous difference between intact and cracked pavements. The established criteria, involving surface deflection and surface modulus indicators, are verified to be reasonable and viable for filtering the FWD testing technology.

This study calculated and analyzed the critical load position and influencing factors of interlaminar shear stress, with focus on the characteristics of and existing studies on continuously reinforced concrete and asphalt concrete (CRC+AC) composite pavement structure. The calculation and analysis were conducted using heat transfer theory, mechanics theory, and finite element method. Interlaminar structure and materials, as well as technology for CRC layer surface treatment, were investigated through indoor experiments and engineering application examples on the basis of interlaminar shear stress. Results show the following: (1) Longitudinal and lateral slips occur in CRC+AC structure because of weak interlaminar shear strength. (2) Interlaminar maximum shear stress decreases as the thickness and modulus of the AC layer increase, with the decrease trend being more obvious with increasing thickness of the AC layer. This trend is also observed along with the minimal effect of the thickness of the CRC layer on interlaminar maximum shear stress. As indicated by the analysis and calculations, combined with the measurements and construction experience of test road, the recommended thickness for AC layer is no less than 6 cm. It is recommended the spraying-type structure should use to treat the interlayer of CRC+AC structure, SBS modified asphalt use as spraying asphalt, and the baring technique use to treat the surface of CRC layer. These results can serve as important reference for the rational design of rigid-flexible composite asphalt pavements.

Low average temperature, large temperature difference, and continual freeze-thaw (F-T) cycles are the typical climatic characteristics of cold plateau regions. F-T cycles and the asphalt-aggregate ratio of an asphalt mixture have been analyzed using a uniaxial compressive test under F-T cycles. The results show that the compressive strength and resilient modulus decrease with an increase in the number of F-T cycles. The mixture performance declines sharply in the initial F-T cycles and gradually gentle after 8-10 F-T cycles. Further, the asphalt-aggregate ratio has a significant influence on the compressive characteristics of the mixture under F-T cycles: a lower asphalt-aggregate ratio leads to a better compressive performance than a higher asphalt-aggregate ratio. A higher asphalt-aggregate ratio leads to a small loss ratio of compressive performance under F-T cycles. The results also reveal that F-T cycles obvious impact on the compressive properties of the mixture and that the use of asphalt concrete (AC)-13 with an optimum asphalt content (5.5%) or more can improve the low-temperature compressive performance of the mixture under F-T cycles.

Choosing two common warm mix modifiers (EC120 and Sasobit), adopting bulk density as the index to measure the effect of compaction, taking the temperature corresponding to the maximum density as optimum temperature, the asphalt mixture sample is formed under this temperature, and the road performance of warm mix asphalt is studied through immersion Marshall test, freeze-thaw split test, rutting test, bending and fatigue tests. The experimental result shows that (1) both modifiers can improve asphalt's high temperature performance, deformation resistance, and temperature sensitivity, while the low temperature performance of the asphalt is decreased a little; (2) water stability, high temperature stability, and fatigue resistance of the warm mix asphalt are all better than that of hot mix asphalt, whereas the low temperature crack resistance is mildly worse than that of hot mix asphalt. The paving of the experimental road proved to be better when the warm mix asphalt was used.

The dynamic performance of large-span steel-concrete composite bridges with external tendons is investigated by deriving the formula of equivalent damping ratio of composite bridges, and by analyzing the influence of shear connectors stiffness of composite girders, interface slip, external tendons, and pile-soil dynamic interactions on the dynamic properties of steel-concrete composite bridge. Finite element calculations indicate that the equivalent damping ratio has significant influence on the dynamic response while the shear stiffness of grouped stud shear connectors and the prestressed levels of external tendons have different but relatively smaller influence on the free vibration frequency of long-span composite bridges; the influence of pile-soil interaction on the structural dynamic response of the composite bridge is clear.

Based on the accurate analysis of the time history of bridge buffeting responses and considering the nonlinearity factors of the structure and wind load, the non-Gaussian response of a structure is derived. The Hermite moment model is introduced to transform the unknown distribution responses into standard Gaussian random processes based on their first four moments, and the dynamic reliability of the structure under strong wind conditions is then numerically analyzed in combination with the Poisson process method. A long-span suspension bridge at the East Sea of China is analyzed and the buffeting dynamic reliability of the stiffening girder is discussed in detail. The results indicate that (1) the middle support section of the stiffening girder is the critical section under fluctuating wind conditions and the dynamic reliability decreases as the wind speed increases, (2) nonlinear effects in the structure are apparent under strong wind conditions, and (3) the common assumption of Gaussian process will produce inaccurate results and unsafe bridge design.

According to the construction characteristics and the specialties of stress distribution in the top slab of a prestressed concrete box girder bridge, two improvements on the submodel method have been made on the basis of the conformation of the internal force. The influence of the construction method is considered by the entire bridge analysis, and the influence of the transverse factors on the transverse normal stress is considered on the basis of the submodel. The transverse normal stress distribution patterns of a bridge deck structure under the conditions of different locations in the transverse direction of the bridge and different parameters of carriage axles and prestress losses are analyzed. The main reason that induced longitudinal cracks in the prestressed concrete box girder is studied from the viewpoint of transverse stresses of the bridge deck. Further, a method considering the local mechanical state of a prestressed concrete box girder bridge deck is summarized and can be used as a reference for design and maintenance management.

The procedure of constructing the bored piles of a new bridge is simulated by using the three-dimensional finite element method. The variance of soil body stress, the deformation in each step of the construction, and the stress variance of the existing pile foundation are predicted. The following analysis results are obtained: (1) The construction of a new abutment affects the displacement and structure stress of existing bridge piles; (2) Every step of the construction process affects the displacement of the lower part of the foundation pit; (3) The influence of the first and third steps on the stress of the existing bridge piles is larger compared with other steps; (4) Given the surrounding soil disturbance it causes, the construction of a new pile foundation has little influence on the settlement of existing bridge piles. In view of these findings, the following guidelines are recommended: (1) The first and third steps should be given more attention as they are the key sources of risk; (2) The soil surrounding the existing pile should be reinforced by grouting; (3) Where possible, the strength of the retaining wall structure and brace should be improved; (4) A monitoring and warning system should be created based on information management.

Based on this reality that surrounding rocks of deep undergrounds engineering repeatedly bear geological force and excavation disturbance, the integrity and mechanical properties were weakened, it is thought that the stress-strain relation submits to the post-peak softening joint model, and then considering other parameters, such as joints, initial geostress, strength, and deformation that affecting the rock mass property. A simulation scheme is designed, and the FLAC^3D numerical software is used to reproduce the process of zonal disintegration. The simulation results show that (1) The existence and distribution of joints have a great impact on the form and scale of zonal disintegration in jointed rock, and the relative relation between rock mass strength and initial geostress is the key to zonal disintegration; (2) Zonal disintegration will emerge when the initial geostress exceeds the rock uniaxial compressive strength; (3) Initial geostress is approximately proportional to rock mass strength, increase in Poisson's ratio, amount of zonal disintegration, extended length, and range of rupture zone, contrary to the trend displayed by the friction angle. The results partly reveal the mechanical mechanism of zonal disintegration and provide a beneficial reference for the establishment of supporting design theory in deep surrounding rock.

During the operation period, soils surrounding a cross-river tunnel are under persistent disturbance owing to heat conduction, resulting in a change in the microstructure and engineering properties. Long term observations of temperatures outside of a shield tunnel segment and shallow soil temperatures are carried out, and the annual change characteristics are analyzed. A 3D heat transfer numerical model of the shallow-buried section of a cross-river tunnel is established, the measured temperature of ground surface and tunnel segment are applied as boundary conditions, and the finite difference method is used to simulate the soil temperature field. The simulation results are compared to the measured data to verify the model reliability and precision, and the characteristics of the temperature field evolution of the region surrounding the tunnel are investigated. The analysis results can be used as a reference for designers in related fields.

To represent the road network operation effectively, a model for road bearing capacity (the product of speed and flow) is proposed, and the reliability of road network is also evaluated based on the mass traffic data with the aid of reliability engineering. Specifically, the bearing capacity is proposed after analyzing the operation characteristics of road network with existing mass data. Then, with the help of statistical knowledge and distribution fitting of the detect data, it is found that the values of the bearing capacity of road network are normally distributed. Moreover, the reliability of the bearing capacity is proposed based on reliability engineering, in order to obtain the framework of the bearing capacity changing with space-time. The results show that the proposed model of bearing capacity and its framework changing with space-time can simulate road network operation effectively.

Because of the aggressive and saturated traffic on the current urban arterials, traffic congestion often occurs, traffic lights periodically interrupt traffic, resulting that vehicles frequently block upstream intersections. However, the traditional continuous traffic flow models are unable to estimate the travel time on saturated urban arterial roads with stop-and-go traffic flow. In view of this, an innovative algorithm for arterial roads travel time estimation based on vehicle platoons is proposed to meet the timing requirements of interrupted traffic flow. Using high-resolution and real-time traffic data acquired by existing detectors on a road, research efforts are devoted to discriminating and matching platoons, thus attaining the goal of estimating the travel time on saturated urban arterials. Simulation studies based on Q-Paramics show ideal results after comparison between the estimated results of the proposed algorithm and observed results of the simulation model. The results prove the rationality and validity of the algorithm. Thereby the paper provides an academic basis for researching the state of traffic on saturated urban arterials.

An integrated cold chain inventory model of a manufacturer, a distributor, and multiple retailers in a finite horizon is established. The three-echelon model assumes that the demand rate is a time-varying function and that the deterioration rate and production rate are constant. To reflect the value added to the cold chain inventory in this model, the objective function is defined to maximize the total system profit. The solution procedures, a numerical example, and a sensitivity analysis are provided. Exponential demand rate is used in the numerical example. An optimized inventory strategy is derived through a comparison of the profit. The results show that the integrated strategy leads to a higher total system profit compared to independent decision approaches.

An energy consumption logarithmic mean divisia index decomposition model is built and applied to quantitatively analyze the effects of structure, energy consumption intensity, and turnover of freight transportation on freight transportation energy consumption during 1990-2011. The results demonstrate that a dramatic growth in freight turnover is the main driving force for the increasing in freight transportation energy consumption,which is further intensified by a remarkable in creasing in high-energy-consuming transportation modes' increased proportion. However, the decline in energy consumption intensity of transportation mode is insufficient to restrain the growth of freight transportation energy consumption; therefore, the increasing trend in freight transportation energy consumption is unavoidable. Consequently, integrated measures should be taken to ensure sustainable development of transportation.

A nonlinear tractor-semitrailer vehicle simulation model is established based on TruckSim used to validate the proposed control scheme. The yaw dynamics of the entire vehicle is stabilized by applying differential braking to the wheels of the tractor and the trailer. The control system, which was designed in Matlab/Simulink, is a two-level structure with the upper yaw moment controller outputting an additional yaw moment and the lower control allocator realizing the additional yaw moment by appropriately coordinating the wheel brake actions of the tractor and the trailer. A Trucksim-Simulink co-simulation model is constructed, and based on which the proposed control scheme is validated by a single-lane change maneuver on a slippery road. Simulation results reveal that designing and evaluating vehicle stability control strategies with the TruckSim-Simulink co-simulation method is effective. The proposed control scheme can significantly improve the vehicle yaw stability and roll stability.