Numerical Investigation on the Transverse Vibration of Prestressed Large-Span Beams with Unbonded Internal Straight Tendon

Abstract

This paper deals with the effect of the prestress load on the free and forced dynamic behavior and vertical vibration of the prestressed beams. The analysis applies both the analytical frequency equation and the finite element method (FEM) using ABAQUS software to predict the fundamental natural frequency (FNF) of the simply supported unbonded prestressed beams. The energy method has been employed to derive the effective prestressing load to determine the eccentricity effect. In regard to the forced response of the prestressed beam, a moving point load with a constant value and various velocities and excitation frequencies is applied. Extensive parametric studies are carried out taking into account different factors including prestress load, eccentricity, concrete ratio, span-to-depth ratio, velocity, and frequency of the moving load. The comparison of the FNFs obtained by the formula with those obtained from FEM models indicates that the results are in a good agreement. This convergence demonstrates that the proposed formulation can predict the FNF of the eccentrically prestressed beams with high reliability. The time-histories curves for midspan displacement of the unbonded prestressed beams and the dynamic magnification factors are also evaluated. The results illustrate that the aforementioned factors have an indispensable contribution to the beam dynamic behavior.

Aspects of Vibration-Based Methods for the Prestressing Estimate in Concrete Beams with Internal Bonded or Unbonded Tendons

“…Since the serviceability and the safety of prestressed concrete members rely on the effective state of prestressing, the development of tools and dynamic procedures capable of estimating the effective prestress loss have been widely carried on [9][10][11]. Since the 1970s, many researchers focused on structural dynamics as a possible way to estimate prestressing [12][13][14][15][16][17][18]. Vibration-based approaches have been proven successful for damage detection purposes in multiple theoretical analysis and case study analyses [19][20][21][22].…”

Effect of the Cross-Sectional Shape on the Dynamic Response of a Cantilever Steel Beam Using Three Modal Analysis Methods

“…The Euler-Bernoulli beam principle is used. Ghaemdoust et al [7] used the analytical and the finite element method to determine the fundamental natural frequency of unbonded pre-stressed beams. Adair and Jaeger [8] calculated non-uniform cantilever beams with a free transverse vibration caused by an axially and transversely eccentric tip mass.…”

Numerical Analysis of the Influence of Prestressed Steel Wires on Vehicle-Bridge Coupling Vibration of Simply Supported Beams on High-Speed Railway

“…Fang (2020) found that the natural frequency of PC continuous beams was related to the number of diverters but had little to do with the arrangement of external prestressed steel wires by using the energy method considering the second-order deformation of external prestressed steel wires. Considering the influence of parameters such as prestress, Ghaemdoust et al (2021) summarised a set of methods for predicting the fundamental frequency of PC beams, comparing the theoretical values with the results of finite element models. The relationship between frequency and the prestressed load is obtained through impact load test on nine PC beams prestressed by the posttensioning method (Noble et al, 2014).…”