Dynamic behaviour of underspanned suspension road bridges under traffic loads

Underspanned suspension bridges are structures with important economical and aesthetic advantages, due to their high structural efficiency. However, road bridges of this typology are still uncommon because of limited knowledge about this structural system. In particular, there remains some uncertainty over the dynamic behaviour of these bridges, due to their extreme lightness. The vibrations produced by vehicles crossing the viaduct are one of the main concerns. In this work, traffic-induced dynamic effects on this kind of viaduct are addressed by means of vehicle-bridge dynamic interaction models. A finite element method is used for the structure, and multibody dynamic models for the vehicles, while interaction is represented by means of the penalty method. Road roughness is included in this model in such a way that the fact that profiles under left and right tyres are different, but not independent, is taken into account. In addition, free software {PRPgenerator) to generate these profiles is presented in this paper. The structural dynamic sensitivity of underspanned suspension bridges was found to be considerable, as well as the dynamic amplification factors and deck accelerations. It was also found that vehicle speed has a relevant influence on the results. In addition, the impact of bridge deformation on vehicle vibration was addressed, and the effect on the comfort of vehicle users was shown to be negligible.

Methods for evaluation of rail-highway grade crossing improvements. Final report.

Mode of access: Internet.

Models of pedestrian crossing behavior at signalized intersections.

Texas Department of Transportation, Austin

Rail-highway crossing safety fatal crash and demographic descriptors.

National Highway Traffic Safety Administration, Office of Research and Development, Washington, D.C.

Motorists' requirements for active grade crossing warning devices. Final report.

Federal Highway Administration, Traffic Systems Division, Washington, D.C.

Summary statistics of the national railroad-highway crossing inventory for public at-grade crossings. Final report.

Federal Railroad Administration, Office of Policy and Program Development, Washington, D.C.

A preliminary laboratory investigation of passive railroad crossing signs. Final report.

Mode of access: Internet.

A methodology for determination of grade crossing resource-allocation guidelines. Final report.

Federal Railroad Administration, Office of Research and Development, Washington, D.C.

Urban crossing problems. Final report.

National Highway Traffic Safety Administration, Washington, D.C.

Examination of unsignalized intersection, straight crossing path crashes and potential IVHS countermeasures. Final report.

National Highway Traffic Safety Administration, Washington, D.C.

Examination of signalized intersection, straight crossing path crashes and potential IVHS countermeasures. Final report.

National Highway Traffic Safety Administration, Washington, D.C.

Innovative concepts and technology for railroad-highway grade crossing motorist warning systems. Vol. I: overview and concept generation and analysis. Final report.

Transportation Systems Center, Cambridge, Mass.

Innovative concepts and technology for railroad-highway grade crossing motorist warning systems. Vol. II: the generation and analysis of alternative concepts. Final report.

Transportation Systems Center, Cambridge, Mass.

The effectiveness of strobe lights as supplemental warning devices at protected railroad grade crossing : (final report) /

Bibliography: p. [20]

Gender differences in factors predicting unsafe crossing decisions in adult pedestrians across the lifespan: a simulation study

Adult pedestrian accident data has demonstrated that the risk of being killed or seriously injured varies with age and gender. A range of factors affecting road crossing choices of 218 adults aged 17-90+ were examined in a simulation study using filmed real traffic. With increasing age, women were shown to make more unsafe crossing decisions, to leave small safety margins and to become poorer at estimating their walking speed. However, the age effects on all of these were ameliorated by driving experience. Men differed from women in that age was not a major factor in predicting unsafe crossing decisions. Rather, reduced mobility was the key factor, leading them to make more unsafe crossings and delay longer in leaving the kerb. For men, driving experience did not predict unsafe road crossing decisions. Although male drivers were more likely to look both ways before crossing than male non-drivers, the impact of being a driver had a negative effect in terms of smaller safety margins and delay in leaving the kerb. The implications of the different predictor variables for men and women for unsafe road crossing are discussed and possible reasons for the differences explored.