Advanced Materials Research Vols. 838-841

Abstract: The buckling strength of stiffened flange plate under compression was researched by referring to BS5400, Japanese Specification for Highway Bridges and Eurocode in order to research calculation methods of stiffened flange plate under compression in foreign design codes of steel bridge which were based on different design theories. Test results of ultimate bearing capacity of stiffened flange plate under compression were compared with calculation results according to those codes. The effects of constructive parameters such as the thickness of flange plate, width of subpanel, thickness of plate and width of inclined web plate in rib on buckling strength of stiffened flange plate under compression were researched respectively. The results showed, when increasing the thickness of flange or decreasing the width of plate divided by rib's web, calculation results of buckling strength increased at first and then leveled off according to Japanese Specification for Highway Bridges. However the buckling strength declined slowly according to BS5400 and Eurocode. When increasing the thickness of plate or decreasing the width of inclined web plate of rib, calculation results increased at the beginning and leveled out then. If ribs satisfy the rigidity demands, calculation results of buckling strength would remain the same as the sizes of rib were changed according to Japanese Specification for Highway Bridges.

Abstract: Based on the uniform experimental design method and combining with the additional lateral pedestrian role derived from social force, this paper establishes human-bridge dynamic interaction model and calculates dynamic response of simply supported structures with different span, damping ratio, walking stride frequency and other parameters under the man-bridge dynamic interaction. The acceleration response spectrum is obtained by FFT transform of acceleration response. Then RMS-acceleration response spectrum is calculated in accordance with ISO overall frequency weighting method and the response spectrum envelope formula is fitted by parametric analysis.

Abstract: To investigate suitability of the perpetual pavement under ultra-heavy loads, a test road was constructed on expressway in Shandong province of China. There were five pavement structures include semi-rigid asphalt pavement, each was instrumented with gages for measuring the strains of asphalt base layer, the vertical stress of subgrade, temperature of asphalt layers. The analysis of the strain data indicated that the strain values are affected by the temperature, the vehicle load, axle type, and the pavement structure combination. To research the response of different structure, tested different axle and load at different temperature, then different pavement response models were developed that accounts for layer thickness, axles load, pavement temperature and equivalent modulus of pavement foundation. The models provides good references under heavy vehicle loading and China local climate, it will be useful for perpetual pavement design.

Abstract: This paper comprehensively analyses domestic and abroad prediction technology of slope disaster, mainly summarizes the prediction models and the prediction criterions, and discusses the applicability and inadequacy of the prediction models and the prediction criterions.

Abstract: Based on LabVIEW platform, a highway nondestructive detection system was developed to detect highway subgrade layer and strcture characteristic. The integral principle of this system is dispersion characteristics of Rayleigh wave in different medium and the pronounced relationship between propagation velocity of Rayleigh wave and physical-mechanical properties of the medium. Using this test system to conduct a field test on a highway in Henan province and comparing the results with the actual situation, the results validated the practicability and reliability of the system.

Abstract: Theoretical analysis combined with experimental study was conducted to determine the proper lane width for urban car-only underground road. Vehicle trajectory data were collected in the experiment using three different ways including naturalistic driving experiment, video image processing and driving simulation. Lateral offset of each vehicle moving on the lane were obtained to determine the lane width. The results shows that for the car-only underground road, the design vehicle width is 1.8m,considering the safety margin and driving comfort, the minimum lane width 3m and 3.25m are reasonable and safe for the design speed 60km/h and 80km/h respectively.

Abstract: Two level zone index system of the provincial highway geotechnical zone was established on the basis of analysis of the relationship between geotechnical elements and highway engineering. The highway rock-soil type conversion rules and the zone standard of two level zone indexes were set through comparative analysis of the characteristics of rock-soil on the engineering geological map. According to the general principles and methods of zone study, the research framework of provincial highway geotechnical zone was constructed. Under the guidance of this framework, Shandong province highway geotechnical zone was completed and the whole research area was divided into 2 grade I and 5 grade II. The results indicate that the new highway geotechnical zone can better reflect the variation of rock-soil engineering properties in Shandong province. The result verifies the scientificalness and effectiveness of the research framework of provincial highway geotechnical zone and provides basic data for research on highway geotechnical zone of nationwide.

Abstract: Severe rutting, cracks and moisture damage are presented on conventional semi-rigid base asphalt pavements not long after completed in China. This phenomenon indicates that conventional philosophy on pavement design could not meet more and more frequent and heavy vehicle. With high structural capacity for high traffic volume and heavy loads, the Perpetual Asphalt Pavements (PAPs) solve those problems well. Meanwhile they need minimal or no major structural rehabilitation and/or reconstruction exercises in their life, which ensures low user-delay. Three PAPs, including semi-rigid base asphalt pavement, flexible base asphalt pavement, and combined base asphalt pavement, are put forward for the northeast area in China considering its climate, traffic characteristic. Finite element method is utilized to analyze response of PAPs under heavy loads. Two key factors, i.e. tensile horizontal strains at the bottom of asphalt layers and compressive vertical strains are investigated. Also the capacities of the structures on bearing overloading are estimated. Four types of wheel and axle, including single axle and single tire, single axle and dual tires, dual axles and dual tires, and tri axles and dual tires are adopted in finite element models. The shapes of tire-pavement contact area are either circular or rectangular to simulate standard load or overloading respectively. When rectangular shapes are adopted, the contact area sizes and the distribution of pressure are varied. Conventional asphalt concrete and high modulus asphalt concrete are adopted. Simulations are done. The competences of the three pavement structures on fulfilling long lives are evaluated.

Abstract: In order to study the storage-infiltration effect of rainfall for sunken greenbelt in urban road, its storage-infiltration capacity of rainfall runoff was analyzed based on the rainfall balance equation of urban road in the time interval, and then the computational formulae of storage-infiltration rate was derived. Influence factors on storage-infiltration rate, such as design recurrence interval of rainfall, soil infiltration coefficient, greenbelt rate, and depth of sunken greenbelt, etc. were computed and analyzed by using the derived computational formulae with the rainfall intensity of Changchun city. Results show that: on the same condition, storage-infiltration rate of rainfall for sunken greenbelt in urban road increases linearly with the increase of soil infiltration coefficient, greenbelt rate, and depth of sunken greenbelt, and decreases with the increase of design recurrence interval of rainfall. Sunken greenbelt with depth of 0.05 ~ 0.25m can storage-infiltrate all of the rainfall that falls on the urban road when the greenbelt rate of urban road ranges from 20% to 40%. Eco-design program of sunken greenbelt in urban road is reasonable and feasible, and its storage-infiltration effect of rainfall is remarkable.

Abstract: Asphalt pavement with semi-rigid base is the major structure adopted in the new built highway and municipal roads in China. So as to reduce the unfavorable impact on the rehabilitation of municipal roads which require quick resumption of traffic, better base materials should be adopted. If a pavement base fails, the flexible base, i.e. large stone asphalt mixture (LSAM), should be employed in the pavement rehabilitation practice. Focusing on the practice pavement sections using LSAM as base in Hangzhou municipal roads, the effect factors of subgrade modulus, base modulus and base thickness on surface deflection and bending strain in base bottom is analyzed. That work is done through finite element method of software BISAR3.0. The results provide a practice reference for municipal roads rehabilitation needing to open traffic early.