Seismic response of bridge structures under non-uniform ground excitations

Based on the orthogonal expansion method of stochastic processes, seismic acceleration processes can be represented as a linear combination of deterministic functions modulated by a set of mutually independent random variables. In conjunction with the probability density evolution method, the random seismic response of bridge structures can be successfully researched. A long-span bridge structure is taken as an example. The probabilistic information of the response of a long-span bridge structure in different control under earthquake excitations is investigated. The investigation provides a new approach to the random seismic response analysis of long-span bridge structures.

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Influence of Transient and Partial Footing Separation on the Seismic Response of Skewed Bridges with Soil Support

International Journal of Structural Stability and Dynamics ◽

10.1142/s0219455421501327 ◽

2021 ◽

pp. 2150132

Author(s):

Ziqi Yang ◽

Chern Kun ◽

Dongliang Meng ◽

Nawawi Chouw

Keyword(s):

Seismic Response ◽

Large Scale ◽

Bending Moment ◽

Bridge Piers ◽

Seismic Load ◽

Skew Angle ◽

Skewed Bridges ◽

Design Spectrum ◽

Bridge Structures ◽

The Impact

Previous research has shown that the transient and partial footing separation is one of the effective methods to reduce the impact of earthquakes on bridge structures. The separation will not only temporarily stop the transfer of seismic load to structures, but also activate rigid-like body motions of the bridge piers. Most of current investigations involving footing uplift only focused on straight bridges. The influence of skew angle is rarely considered. Even though skewed bridges are common and more vulnerable to seismic load. This work reveals the simultaneous influence of skew angle and footing uplift on soil on seismic response of bridges. A bridge with a 30∘ or 45∘ skew angle, in addition to a straight bridge, was excited using a large-scale shake table. The ground excitations were stochastically simulated based on design spectrum of New Zealand standard. The result revealed that with increasing skew angle bridges will have frequent footing uplifts. In the case of a straight bridge, although allowing footing uplift is beneficial in reducing the bending moment at the pier support, it increases the longitudinal girder displacement. In contrast, in the case of 30∘ and 45∘ skewed bridges, uplifts increase the bending moments of piers and the displacements of the girder, especially in the transverse direction.

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A New Pulse-Based E-R-μ Method for Predicting the Peak Seismic Response of Highly Nonlinear Bridge Structures

IABSE Symposium, Vancouver 2017: Engineering the Future ◽

10.2749/vancouver.2017.0110 ◽

2017 ◽

Author(s):

Viacheslav Koval ◽

Constantin Christopoulos ◽

Robert Tremblay

Keyword(s):

Seismic Response ◽

Highly Nonlinear ◽

Bridge Structures

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The Influence of Trains on the Seismic Response of Simply-Supported Beam Bridges with Different Pier Heights Expressed through a Safety Factor

10.21203/rs.3.rs-656142/v1 ◽

2021 ◽

Author(s):

Lizhong Jiang ◽

Kang Peng ◽

Jian Yu ◽

Wangbao Zhou ◽

Yongjian Zuo

Keyword(s):

Seismic Response ◽

Safety Factor ◽

High Speed ◽

Dynamic Effect ◽

Track Structure ◽

Simply Supported Beam ◽

Simply Supported ◽

Bridge Structures ◽

Track Bridge ◽

Bridge System

Abstract With the extension of high-speed railways to high-intensity earthquake regions, it is impossible to avoid structural vibrations due to the joint action of trains and earthquakes. Therefore, it is of great significance to study the influence trains on bridge structures exposed to earthquakes. In this paper, a coupled finite element analysis model of a high-speed railway vehicle-bridge was established by considering a simply-supported beam bridge with the China Railway Track System (CRTS) II plate and the CRH2C high-speed train. The correctness of the model was experimentally verified. By considering the ground motion randomness, the influence of the train on the response of the bridge structure exposed to an earthquake was analyzed. Also, the influence level of the running train on the seismic response of bridge structures with different pier heights was studied. The results revealed that the train dynamic effect significantly reduced seismic responses of piers and supports, and that the effect itself decreased with the pier height increase. Furthermore, the dynamic effect of the train increased the seismic response of the track structure, while the bridge pier height had little influence on the dynamic efficiency of the track structure. For different pier heights, the probability distribution model of the train dynamic effect for the track-bridge system seismic response was considered as the normal distribution. This indicated that the seismic response of the track-bridge system under vehicle condition could be simplified as the product of the seismic response and safety factor under no vehicle condition.

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