Safety Analysis of Vehicles Running on Bridge During An Earthquake

Abstract eng:
This study mainly focused on seismic response analysis of highway vehicles during the earthquake running on the elevated structure. Elevated structures those mainly dominated in city expressways and highways in mountainous areas; seismic response of such structures is spatially varied with type and properties of structures. Actual earthquake acceleration that excites the vehicle running on it, depends on the location where the response of structures subjected at that particular time. Local soil condition of the surrounding area play a role in vehicle excitation when they are running on the ground but that difference might be negligible in comparison with the structural response. Virtual symmetrical cable-stayed bridge of length 1330 m is considered in the study with a central span of 580 m between two central towers. Kobe and El Centro earthquake ground motions are selected for structural analysis. Nodal responses on deck level are calculated using finite element analysis of the model. Input earthquake motion for seismic response analysis of the vehicle is calculated through interpolation of nodal responses of the structure at deck level. Location of the respective vehicle that depends on speed and its’ origin is the base of the interpolation. Lagrange’s three-point formula is used as the data follows simple parabolic function in between three points for interpolation. Interpolated earthquake accelerations are shown for the cases of different origin and speeds. Frequency and the amplitude of interpolated earthquake motions are varying with the origin and speed. Vertical response of the vehicle is calculated using two degrees of freedom system of quarter vehicle model. Seismic responses of vehicle in lateral and longitudinal directions are calculated using circular path and linear momentum (CPLM) method. Magic Formula Model (MFM) is considered on determining the tyre forces acting in the vehicle. Passenger car, bus and truck are used in the study as different types of vehicles. We consider the ideal condition of vehicle running on the bridge that driver’s reaction is not taking in to account for this study on controlling the vehicle. Single vehicle model running through the bridge analyzed for the cases of different speed and the origin. Speeds of the vehicle ranging from rest condition to the 30.0 m/sec are analyzed for all three types of vehicles when the origin of the vehicle is starting of the bridge. Lateral displacements are increased with the ascending value of the speed in all types of vehicle when the earthquake motion was used from El Centro earthquake, In contrast with this trend, response of vehicles for Kobe earthquake is almost in descending order but very small in quantity. When the origin of the vehicle changed from start of the bridge to the last point of the bridge with the constant speed of 20 m/sec for all cases, lateral displacements of the vehicles follows the different trend. Vehicle response for the cases of vehicle position within bridge and exit from the bridge during shaking, affect on the result.

• Export as: BibTeX | MARC | MARCXML | DC | EndNote | NLM | RefWorks
• Add to your basket