Vibrations Of Suspension Bridges Research Articles

Monitoring, intelligent perception, and early warning of vortex‐induced vibration of suspension bridge

Monitoring, intelligent perception, and early warning of vortex‐induced vibration of suspension bridge

Vehicle-Induced Vibration of Suspension Bridge with CFRP Cables Based on Different Cable Replacement Criteria

Vehicle-Induced Vibration of Suspension Bridge with CFRP Cables Based on Different Cable Replacement Criteria

Numerical Simulation of Flutter of Suspension Bridges

A method for simulating the spontaneous, wind-excited vibrations of suspension bridges is described. The approach is based on a numerical model that treats the bridge and flowing air as elements of a single dynamic system; and all of the governing equations are integrated numerically, simultaneously, and interactively. It is shown that the present simulation predicts the same onset of flutter as the analysis of Fung. Unlike Fung’s analysis, the present analysis provides the solution in the time domain, is not restricted to periodic motions or linear equations of motion, and provides post-onset behavior as long as the effective angles of attack are not large enough to produce stall. As a consequence, the present analysis can be a very effective tool for the design of flutter-suppressing control systems. Because the equations are solved numerically, nonlinear supports do not present a problem. In the present work, it is shown how the nonlinear springs lead to limit-cycle responses.

Vibration of Suspension Bridges under Vehicular Movement

A continuum analysis for determining the flexural‐torsional vibration of suspension bridge under vehicular movement is presented. The dynamic analysis duly considers the nonlinear bridge‐vehicle interactive force, eccentricity of vehicle path, surface irregularity of the bridge pavement, cable‐tower connection and end conditions for the stiffening girder. The surface irregularity of the bridge pavement is considered as a stationary random process characterized by a power spectral density function (PSDF) of the surface irregularity. The irregular profile of the bridge pavement is synthetically generated from the PSDF using Monte Carlo simulation technique. The analysis makes use of normal mode theory and calculates the response in time domain utilizing an iterative scheme and a few closed‐form expressions. The responses are obtained and compared for three types of vehicle models, namely, 3‐D, 2‐D, and single sprung mass system. A parametric study is also conducted to investigate the influence of some important bridge and vehicle parameters on the dynamic behavior of the bridge.

Vibration of Suspension Bridges under Moving Loads

The problem relates to the transient vibration of a single-span suspension bridge which is traversed by a constant force moving with constant velocity or a pulsating force moving with constant velocity. Damping is zero and there is no mass associated with the moving forces. Equations of motion are derived and solved. Solutions are obtained for the deflections and stresses of the truss and for the increase in horizontal component of cable tension. The theory is based on the deflection theory equations of suspension bridges. It is linearized by assuming that the increase in cable tension due to live load is small compared to the dead load cable tension. A numerical example illustrates the theory. The results of the example show large magnifications of stress (on the order of 2.70) when the moving pulsating force is driven at the frequency of the first symmetric mode. Also, in general, there is no appreciable dynamic effect associated with moving constant forces on long-span bridges. The dynamic effect of moving constant forces, however, becomes more pronounced on short-span bridges having a low frequency associated with the first asymmetric mode.

Wind-Induced Vibration of a Pipe-Line Suspension Bridge, and Its Cure

Abstract This paper concerns a solution to a critical pipe-line bridge-vibration problem. The answer to the problem resulted from the application of scientific research methods. As the first step toward a solution, careful measurements were made which laid bare the fundamental cause of the trouble. Following this, several possible solutions were conceived, and the most practical appearing one was selected for testing. Dynamic tests on models were made to verify the choice and to aid in full-scale design. Finally, a full-scale aerodynamic vibration damper was applied to the suspension bridge and the results checked by scientific measurements. The resulting solution for preventing vibration of suspension bridges is thought to be completely new, and the subject pipe-line bridge, the first of its kind to which it has been applied.