Structural responses of transit buses: Impact of wheelchair loads

The structural responses of typical transit buses with and without wheelchair loads and the changes in these responses from one bus design to the next were investigated. To this end, finite-element computer models, with and without wheelchairs, wheelchair restraints, and wheelchair lifts, were developed for two 7.6-m transit buses designed in 1989 and 1992. These models were each analyzed under bus deceleration with seats attached to the bus floor only, and with seats attached to the bus sidewall and floor. With respect to the structural responses of these typical transit buses to bus deceleration it was concluded that (a) maximum member stresses in models with wheelchair loads versus models without wheelchair loads tended to increase in the 1989 bus models and decrease in the 1992 bus models and (b) small to moderate changes in the number, size, and location of structural members from one bus design to the next can have a substantial impact on the maximum member stresses.