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This study proposes a dynamic response analysis procedure for traffic-induced vibration of a monorail bridge and train. Each car in the monorail train is idealized as a dynamic system of 15-degrees-of-freedom. The governing equations of motion for a three-dimensional monorail bridge-train interaction system are derived using Lagrange's formulation for monorail trains, and a finite element method for modal analysis of monorail bridges. Analytical results on dynamic response of the monorail train and bridge are compared with field-test data in order to verify the validity of the proposed analysis procedure, and a positive correlation is found. An interesting feature of the monorail bridge response is that sway motion is caused by torsional behavior resulting from eccentricity between the shear center of the bridge section and the train load.

This paper introduces an analytical procedure to derive equations of motion for the monorail train-bridge interaction based on Lagrange's formulation to investigate riding comfort of moving monorail trains on bridges. A 15DOF dynamic model is assumed for a car in a monorail train that consists of driving, steering, and stabilizing wheels. It is based on the finite element method for modal analysis using three-dimensional models for a monorail bridge. Dynamic behaviors of a rationalized monorail bridge with a simplified structural system are investigated in comparison with those of a conventional monorail bridge using the developed analytical method. Riding comfort of running trains on the rationalized monorail bridge based on ISO2631 is estimated using 1/3 octave band spectral analysis. Observations indicate that a rational type bridge does not engender difficulties related to the riding comfort of the monorail train, even when considering the longest traveling time of passengers between terminals.

SUMMARYThis study is intended to investigate the seismic response of steel monorail bridges using threedimensional dynamic response analysis. We particularly consider monorail bridge-train interaction when subjected to ground motion that occurs with high probability. A monorail train car with two bogies with pneumatic tires for running, steering and stabilizing wheels is assumed to be represented su ciently by a discrete rigid multi-body system with 15 degrees of freedom (DOFs). Bridges are considered as an assemblage of beam elements with 6 DOFs at each node. Modal analysis is used for dynamic response analysis under moderate earthquakes. The seismic response of an advanced monorail bridge that adopts a simpliÿed structural system and composite girders is investigated through comparison with seismic responses of a conventional bridge. The acceleration response of a monorail train is also calculated to investigate the e ect of structural types of bridges on the train's dynamic response during earthquakes. Results show that the seismic responses of the advanced bridges are greater than those of the conventional monorail bridge because of the simpliÿed structural system and increased girder weight that is attributable to composite girders of the advanced bridge. Moreover, the train on the advanced bridge shows greater dynamic response than that on the conventional bridge. Observations reveal that the dynamic monorail train system acts as a damper on the monorail bridge. That fact shows that the existing design, which considers a train as additional mass, yields a conservative result.