Central composite design-response surface methodology was used to determine the best content of raw materials and improve the performance of hot-poured bituminous sealant. Content range and process technology were studied through single factor analysis method. Cone penetration, elastic recovery, creep strength, and creep strain rate "m" were analyzed by central composite model testing. The response surface of the overall desirability was established and the optimal content of raw materials were determined and verified. Analyses of test results indicated that the optimal content of raw materials were as follows: rubber powder-25%, additive-7%, SBS-5%, and SBR-3%. This paper proposes the application of central composite design in the optimization of raw material dosage of hot-poured bituminous sealant.

The longitudinal reinforcement design was analyzed under current specifications of cement concrete pavement design for highway, considering the structural characteristics and limitations of existing studies on continuously reinforced concrete and asphalt concrete (CRC+AC) composite pavements. By using heat transfer theory and the finite element method, the temperature effect of the asphalt concrete (AC) layer was examined, and the influence of the temperature effect on the longitudinal reinforcement ratio of CRC+AC composite pavements was calculated and analyzed. The results show that (1) the longitudinal reinforcement design of CRC+AC composite pavements can disregard spalling, seepage, and thrust failure and only consider the tensile failure of reinforcement; (2) the longitudinal reinforcement ratio of CRC+AC composite pavements can be reduced through the efficient heat insulation of the AC layer, for instance, when the thickness of the AC layer is 10 cm, the longitudinal reinforcement ratio of the CRC layer can be reduced by approximately 0.12%; and (3) the sliding stent is recommended to be used in reinforcement erection, with banding method employed for jointing longitudinal reinforcement with an overlapped length that is approximately 35 times of the reinforcement diameter.

A tension-compression beam fatigue test under continuous sine wave alternating loading for AC-13 was conducted to understand fatigue damage characteristics of an actual asphalt pavement structure under tension and compression stresses. Tension-compression fatigue damage characteristics of asphalt mixtures were investigated using phenomenology based on basic theory of damage mechanics. Tension-compression fatigue test method and influencing factors were introduced; and tension-compression fatigue equation was established via fatigue test results. A tension-compression fatigue damage model was developed based on the damage variable defined by elastic modulus. Damage parameters were determined by fitting fatigue test data. Tension-compression fatigue damage evolution equation regarding stress level was constructed. Results show the following. (1) Fatigue damage parameters α and β increase with stress level; and relationship between damage parameters and stress level is linear. (2) Tension-compression fatigue damage evolution has approximately three stages: damage initiation, stable growth, and unstable failure. (3) The greater the nominal stress level is, the lower the curve of the damage evolution curve is, and the less fatigue damage evolution speed varies with life radio.

The present study discusses the use of the new windscreen pavement/tire noise testing method and the lateral friction coefficient test vehicle to test the skid resistance and noise reduction properties of cement concrete pavements with different surface textures and to analyze the skid resistance and noise reduction mechanisms of pavements with different surface textures. The tests show that the improved noise testing equipment can effectively check the interference of outside noise and ensure the accuracy of test data. In addition, by improving the common surface texture of cement concrete pavements, the pavement noise can be reduced and skid resistance is increased. The noise of porous, exposed aggregate, and longitudinally grooved cement concrete pavements is equal to that of asphalt pavements and all of them display good skid-resistant effect.

To elucidate the frost heaving mechanism of subgrade, as well as reduce cracking, subsidence, and mudding due to water freezing and thawing in seasonally frozen regions, temperature sensors were embedded in the subgrade in a heavily frozen region to automatically monitor subgrade temperature during freeze periods. A drilling investigation was also conducted to determine the typical disease caused by road frost. Results show that (1) The upper roadbed exhibited a wide cooling range and a high cooling rate. (2) The lower roadbed exhibited a narrow cooling range and a low cooling rate; sufficient moisture transfer and accumulation occurred. The depth of the ice accumulation zone is found in this roadbed. (3) Different ice formations developed on various subgrade soils, and the depth and moisture content of these formations presented some regularity. (4) The mean depth of the ice accumulation zone was 1.08 m to 1.65 m, and the scope of mean moisture content was 14.7% to 23%. The maximum moisture content approached or exceeded the plastic limit of soil. Therefore, ice crystals separated, making up the majority of frost heave. On the basis of these findings, drainage and water block measures should be implemented to control subgrade moisture and enhance the management of the homogeneity and density of subgrade fillers. These measures will minimize and prevent frost-related problems.

To examine the seismic active pressure on retaining walls, the pseudo-dynamic method is adopted in deducing the formulas of seismic active earth pressure. The critical rupture angle is analytically solved on the basis of conventional sliding wedge limit equilibrium theory. The influencing factors considered for the formulas are seismic force, surcharge angle, the internal friction angle and cohesion of the backfill for retaining walls, the friction angle and cohesion between retaining walls and backfill, and the inclination of retaining walls. The effects of these factors on critical failure angle and seismic active earth pressure coefficient are analyzed. Results show that the critical rupture angle is less than that is calculated using the Mononobe-Okabe method, in which the soil amplification factor and cohesion of backfill are disregarded. The critical rupture angle decreases with increasing soil amplification factor. The seismic active earth pressure coefficient increases with rising seismic coefficient, inclination of retaining walls, or surcharge angle; this coefficient decreases with increasing internal friction angle of backfill or soil amplification factor. The seismic active earth pressure coefficient also decreases and then increases as the friction angle between retaining walls and backfill increases.

In order to make the study of aerostatic response of suspension bridge catwalk more realistic, the FEA(Finite Element Analysis)model of the catwalk of Lishuihe grand suspension bridge was established based on the FEA software ANSYS. Based on the section model wind tunnel test for the aerostatic tri-component force of the catwalk and considering the geometric nonlinearity and aerostatic nonlinearity of the catwalk of the bridge, a program that can accurately calculate the aerostatic instability of the catwalk of the suspension bridge was established by combining the incremental, as well as internal and external iteration. The 3D nonlinear static wind instability analysis for the catwalk of the bridge was then performed. The research result indicates that (1) the lift force can cause the tension of the load-bearing rope in the catwalk to gradually relax and the torsional stiffness of the small span catwalk to decrease; and (2) the aerostatic torsional instability is caused by the decreased torsional stiffness not being sufficient to resist the aerial torque effect.

The three-component force coefficient of a streamlined bridge section that varies with the Reynolds number (Re) was numerically simulated based on the computational fluid dynamics software FLUENT in studying the Re effect on a bridge section through numerical simulation. Three turbulent models were used in this paper: standard k-ε model, Reynolds stress model, and Spalart-Allmaras model. Several important conclusions were drawn by comparing results of the numerical simulation with those of the wind tunnel test. First, results of the numerical simulation and the wind tunnel test are very similar. Maximum error of the drag coefficient is less than 4%; calculation results of the lift coefficient are greater than the test result; and the relative error is less than 3%. When the Re is less than 6×10⁵, calculation results of the lift pitching moment coefficient is less than that of the test result. When the Reynolds number is bigger than 6×10⁵, calculation results of the lift pitching moment coefficient is greater than that of the test result, and calculation error is less than 6%. The study confirms the existence of the Re effect on static aerodynamic coefficients on a bridge deck. The model should be used to simulate the three-component force coefficient for a streamlined bridge section. Calculation results can meet accuracy requirement through this method.

Aimed at short bridge piers that are vulnerable to brittle shear failure in high earthquake intensity zones, seismic design countermeasures for bridges with short piers were put forward in combination with the Guidelines for Seismic Design of Highway Bridges (JTG/T B02-01-2008). Based on a designed simple two-span pre-stressed concrete T-beam bridge located in a high earthquake intensity zone, specific schemes and suggestions, including seismic isolation technology, multi-column pier design, composite short column (Fiber Reinforced Plastic (FRP) or steel tube), or high-strength transverse reinforcement, were proposed, respectively. By using the numerical analysis model for seismic isolation and the multi-column pier design scheme established by the special finite element software MIDAS, the maximum longitudinal and lateral loads of bridge piers and the pile foundations of different designs under E2 earthquake excitation were compared. It is found that the seismic demand of short piers and foundations for bridges could be decreased significantly by using a seismic isolation design or a multi-column pier design suitable for seismic design of bridges with short piers in high earthquake intensity zones, and the mechanical behavior of short piers and foundations under strong earthquake could be improved. The proposed design schemes could be selected by designers in the seismic concept design stage to improve the seismic performance of bridges with short piers.

Taking the maintenance of a PC cable-stayed bridge as the background, a simulation and calculation analysis of construction control was conducted, and the scheme of stay cable force adjustment was optimized using GQJS (Software of Analysis and Designing of Highway Bridges). Bonding of the steel plates and strengthening by external tendons were achieved, and some construction control targets and safety measures for stay cable force adjustment were provided after the rehabilitation of the tension rocker bearing cables. Adjustment steps and methods were also introduced. The corresponding calculations for the service stage of this bridge were presented. Construction monitoring results showed good force distribution of all stay cables; moreover, the alignment of its main girder was improved after stay cable force adjustment. Concrete stresses, displacement at the top of pylons, and forces of tension rocker bearing cables were also considered. The desired structural goals were achieved in the construction control of the stay cable force adjustment, thereby ensuring structural safety.

This study aims to reflect the original strength of concrete material objectively and accurately by determining the concrete damage degree quantitatively and identifying the relation between damage variable and strength. According to uniaxial compressive stress-strain curve and the strain equivalent principle, the stress-strain curve of damaged concrete is obtained while the concrete subjected to circulate loading has different degrees of damage and strain is beyond that corresponding to peak stress. The relation between the damage variable and concrete strain at different strength grades is derived. The corresponding strain is obtained by testing the damage variable of damaged concrete. The original strength of the concrete material is calculated according to the testing strength of core samples of damaged concrete with a height and diameter of 100 and 150 mm, respectively. Finally, the conclusion is verified by a test.

The measurement and description of the three-dimensional (3D) parameters of bridge surface defects are common technical problems in the field of bridge defect detection. These problems are difficult to solve through conventional methods. However, with the assistance of line-shaped lasers, 3D structure measurements can be converted to two-dimensional ones. Based on an analysis of the applications of 3D measurement techniques in other industries, a 3D measurement method for bridge surface defects is proposed. In this method, the parameters of line deformation are measured using digital imaging and pattern recognition techniques, and then the 3D parameters of bridge surface defects are calculated. The computational formula is also deduced. Subsequently, the feasibility of the method is verified by experiments.

Based on the twin shear unified strength theory, the analytical equations for calculating stress, displacement, radius of plastic zone, and characteristic curve equation of surrounding rock in circular submarine tunnels were proposed under the condition of fluid-solid coupling. As the tunnel is usually located under high water pressure, the effective stress of surrounding rock will be reduced for high pore water pressure and seepage pressure according to the calculation results. This may bring about the arch formation and lower stability of strata. Moreover, intermediate principal stress has a certain influence on the stress, displacement, and radius of the plastic zone of surrounding rock. Hence, it is necessary that seepage and intermediate principal stress are rationally considered in the surrounding rock stability analysis and the lining structure design of submarine tunnels because this is beneficial for maximizing the strength of the surrounding rock. Selecting reasonable strength criterion of rock is the basis for correct analysis in rock mechanics and engineering. The results of this study may be applicable to actual situations in various engineering fields by choosing different coefficients of intermediate principal stress b and effective pore water pressure coefficient η. Further, these may provide a theoretical base and practical value for distinguishing the stability of surrounding rock; designing supporting structure and determining the area of pre-grouting submarine tunnels.

Unmanned aerial vehicle (UAV) technology was introduced in traffic surveillance in sparse road networks, and a UAV allocation method with/without UAV continuous flight distance constraint was proposed. First, the method of choosing the surveillance targets was proposed. The UAV traffic surveillance problem without maximum flight distance constraint was then formulated as a traveling salesman problem, and the simulated annealing algorithm was introduced to solve this problem. As for UAV traffic surveillance problem with continuous flight distance constraint, the K-means clustering algorithm was used to divide the UAV surveillance area into multiple sub-zones to convert this problem into UAV traffic surveillance scenarios without continuous flight distance constraint. Finally, taking the Korla-Kuqa expressway of Xinjiang and its road network as the example, the proposed UAV-based traffic surveillance allocation method for sparse road networks was demonstrated and validated using several field experiments. The experimental results show that UAV is an effective and useful tool for traffic surveillance in the sparse road networks of China's western regions.

To determine the deterioration characteristics of the retroreflective sheeting used for guide signs, this study examined 12-year (1998-2010) observation data on 230 guide signs located in a test square. On the basis of the data, the deterioration curves of sheeting materials were calculated and the mathematical deterioration model for retroreflective sheeting was accordingly constructed. In determining the most suitable reference model, we chose among a linear mathematic model, a second-order polynomial model, and a cubic curve regression model. It was then applied to the signs found along Jiangxi Yongwu expressway in China. This research is expected to provide guidance for the maintenance of traffic signs in our country.

The multi-temperature joint distribution (MTJD) system based on storage-type cold-chain logistics is a contemporary distribution mode. To analyze the economics and social benefits of MTJD and overcome the disadvantages of single-temperature storage type of traditional cold-chain logistics, this paper builds a comprehensive cost model by taking into account the fixed costs, procurement costs, inventory costs, cargo damage costs, transportation costs, and energy costs, to name a few. Through comparative analysis, it is found that MTJD not only reduces purchasing cost, but also decreases delivery times, increases vehicle loading and unloading efficiency, and shortens delivery time. Meanwhile, it realizes energy savings, reduction in fuel consumption, and decrease in various costs such as those incurred in distribution, order processing and inventory, storage, and cargo damage in addition to the significant low-carbon economy.

For the system coordination of transportation-inventory problem in the presence of uncertainty in customer demand, inventory cost, and lead time, this paper, from the point of optimizing logistics cost, establishes the optimization cost model of transportation-inventory system, and transportation cost in the model is taken as a step function of shipment lot size. Based on the fact that the model's optimal solution that can minimize system cost is not always viable in the real world, a coordination mechanism that can embody the purpose of decision-makers and improve the feasibility of model is advanced. In the end, the numerical examples are applied to show the effectiveness of the coordination mechanism: not only can the experience judgment of decision-makers be embodied, but the system cost obtained by the coordination mechanism is smaller than the cost under optimal transportation policy and optimal inventory policy.

The original material of the side impact bar is replaced with ultra high-strength steel. The section dimensions of the side impact bar are considered as design varieties, and its minimum weight is considered as the optimization object. The maximum displacement and residual deformation in door sinking stiffness condition as well as the impact forces under different displacements in side impact condition are considered as constraints of optimization. Sampling points are obtained by optimal Latin square design of experimental method. The multidisciplinary design optimization, which approximates systems with door sinking stiffness and side crashworthiness, is constructed using polynomial response surface regression. Comparing the prediction result of the polynomial response surface regression approximate model and the computer result of the finite element model, the approximate model of the former shows higher accuracy. The approximate systems are optimized using the method of feasible directions. The door sinking stiffness and side crashworthiness are improved, and the weight of the side impact bar is reduced by 34.7%.