Structural Responses of Transit Buses: Impact of Seat-Belt Loads

The objectives of this engineering investigation were to determine the structural responses of typical transit buses under various combinations of seat-belt use and seat type, as well as the changes in these responses from one bus design to the next. To this end, finite-element computer models were developed for two 7.6-m transit buses designed in 1989 and 1992. These models were each analyzed under bus deceleration with full and partial seat-belt use, with seats attached to the bus floor only, and with seats attached to the bus sidewall and floor. The study concluded the following with respect to the structural responses of these typical transit buses to bus deceleration: (1) Maximum member stresses should be lower with full versus partial seat-belt use; (2) maximum member stresses should be higher with wall-mounted versus floor-mounted seats; and (3) 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.