Dynamic characteristics of horizontally curved bridges

Abstract

Horizontally curved bridges have complicated dynamic characteristics because of their irregular geometry and nonuniform mass and stiffness distributions. This paper aims to develop a simplified and practical method for the calculation of the natural frequencies and mode shapes of horizontally curved bridges that would be of interest to bridge engineers for the estimation of the seismic response of these types of bridges. For this purpose, a simple three-degree-of-freedom (3DOF) dynamic model for free vibration equation of this type of bridge has been developed. It is shown that the translational motion of the deck of horizontally curved bridges in the direction that is perpendicular to their axis of symmetry is always coupled with the rotational motion of the deck, regardless of the location of the stiffness center. The model is further exploited to develop closed-form formulas for the estimation of the maximum displacements of the corners of the deck of one-way asymmetric horizontally curved bridges. The accuracy of the model is verified by finite-element model of a horizontally curved bridge prototype in OpenSEES. Finally, the model is utilized to study the influence of the location of the stiffness center with respect to the deck curvature center on the natural frequency and the maximum displacements of the corners of the deck for different curvatures of the deck. The results of free vibration analysis show that the natural frequencies of one-way asymmetric horizontally curved bridges, in general, increase with the increase of the subtended angle of the deck. The results of earthquake response spectrum analysis show that the increase in the subtended angle of one-way asymmetric horizontally curved bridges decreases the radial displacements of the corners of the deck but increases the azimuthal displacement. These two responses both increase with the increase in the distance between the stiffness center and the curvature center.

Effect of the angle of seismic incidence on the response of a long-span curved bridge under spatially varying ground motions

“…To model the abutments, non-linear zero Length elements were used (Table 4) and the shear wave velocity was obtained from PEER (Table 5). The accuracy of the bridge finite element model was verified by the results of Tondini and Stojadinovic [28] and Amjadian and Agrawal [29]. The results of the current study by the mentioned papers are compared and shown in Table 6.…”

Feasibility study of using a semiactive electromagnetic friction damper for seismic response control of horizontally curved bridges

“…This can be done by adjusting the positions of the columns shown in Figure a. More details on this can be found in the previous publications of the authors . The subtended angle of the deck β is the key geometrical parameter of the bridge prototype.…”

“…More details on this can be found in the previous publications of the authors. 17,39 The subtended angle of the deck β is the key geometrical parameter of the bridge prototype. This parameter is proportional to the curvature of the deck κ through β = κL = L/R O , where L is the length of the deck.…”

Influence of Abutment Stiffness and Strength on the Seismic Response of Horizontally Curved RC Bridges in Comparison with Equivalent Straight Bridges at Different Seismic Intensity Levels

“…However, the use of such equivalent bridges is limited to curved bridges with certain limits on their subtended angle and regularity. Irregular geometry and nonuniform mass distribution in curved bridges lead to an excessive in-plane rotation of the superstructure compared to an equivalent straight bridge [19]. Unseating of the superstructure is one of the primary collapse modes of horizontally curved bridges, exacerbated by the increased inplane rotation of the superstructure [20].…”