scholarly journals Dynamic response of long-span bridges subjected to nonuniform excitation: a state-of-the-art review

2019 ◽  
Vol 258 ◽  
pp. 05017
Author(s):  
Seplika Yadi ◽  
Bambang Suhendro ◽  
Henricus Priyosulistyo ◽  
Akhmad Aminullah
Keyword(s):  
Dynamic Response ◽  
State Of The Art ◽  
Ground Motions ◽  
Experimental Studies ◽  
Suspension Bridges ◽  
Long Span Bridges ◽  
Long Span ◽  
Numerical Studies ◽  
Multiple Support ◽  
Support Excitation

In recent years, considerable attention has been paid to the research of dynamic response of long-span bridges with particular emphasis on seismic behavior. Cable-stayed and suspension bridges are the most popular types. Since long-span bridges have multi-supports and extreme lengths, due to the spatial variation effects, the ground motions at different supports might be non-uniform. A state-of-the-art update review of the response of long-span bridges subjected to non-uniform excitation is presented. The review mainly focuses on the theoretical aspects of non-uniform excitation, numerical studies, and experimental studies to verify some of the theoretical findings. In this paper, a review of the use of shake-table in experimental studies of long-span bridges is also presented. The non-uniform cases considered include a time delay with the same support excitations, multiple support excitations, and the combination of the first and the later. The results are discussed and summarized in comparison to the cases of uniform support excitation.

Film thickness in elastohydrodynamically lubricated slender elliptic contacts: Part I – numerical studies of central film thickness

2021 ◽  
pp. 135065012110477
Author(s):  
Marius Wolf ◽  
Sergey Solovyev ◽  
Fatemi Arshia
Keyword(s):  
Film Thickness ◽  
State Of The Art ◽  
Experimental Studies ◽  
Elastohydrodynamic Lubrication ◽  
Large Parameter ◽  
Numerical Studies ◽  
Minimum Film Thickness ◽  
Subsequent Publication ◽  
New Formula ◽  
Increasing Load

In this paper, analytical equations for the central film thickness in slender elliptic contacts are investigated. A comparison of state-of-the-art formulas with simulation results of a multilevel elastohydrodynamic lubrication solver is conducted and shows considerable deviation. Therefore, a new film thickness formula for slender elliptic contacts with variable ellipticity is derived. It incorporates asymptotic solutions, which results in validity over a large parameter domain. It captures the behaviour of increasing film thickness with increasing load for specific very slender contacts. The new formula proves to be significantly more accurate than current equations. Experimental studies and discussions on minimum film thickness will be presented in a subsequent publication.

scholarly journals Concepts and new perspectives for long span bridges

2016 ◽  
Vol 5 (1) ◽  
pp. 75-97
Author(s):  
Fabio Brancaleoni
Keyword(s):  
Conceptual Design ◽  
Present State ◽  
Critical Parameter ◽  
State Of The Art ◽  
Span Length ◽  
Factors Affecting ◽  
Long Span Bridges ◽  
Future Developments ◽  
Long Span ◽  
The Subject

AbstractA discussion of the dominant factors affecting the behaviour of long span cable supported bridges is the subject of this paper. The main issue is the evolution of properties and response of the bridge with the size of the structure, represented by the critical parameter of span length, showing how this affects the conceptual design. After a review of the present state of the art, perspectives for future developments are discussed.

Analytical and experimental studies on optimal details of orthotropic steel decks for long span bridges

2011 ◽  
Vol 11 (2) ◽  
pp. 227-234 ◽  
Author(s):  
Chang-Kook Oh ◽  
Kee-Jeung Hong ◽  
Doobyong Bae ◽  
Heungsub Do ◽  
Taejin Han
Keyword(s):  
Experimental Studies ◽  
Long Span Bridges ◽  
Long Span ◽  
Orthotropic Steel Decks

scholarly journals State-of-the-Art Review on Determining Prestress Losses in Prestressed Concrete Girders

2020 ◽  
Vol 10 (20) ◽  
pp. 7257
Author(s):  
Marco Bonopera ◽  
Kuo-Chun Chang ◽  
Zheng-Kuan Lee
Keyword(s):  
Prestressed Concrete ◽  
State Of The Art ◽  
Nondestructive Method ◽  
Prestress Loss ◽  
Prestress Losses ◽  
Long Span Bridges ◽  
Concrete Girders ◽  
Long Span ◽  
Vibration Responses ◽  
Prestressed Concrete Girders

Prestressing methods were used to realize long-span bridges in the last few decades. For their predictive maintenance, devices and dynamic nondestructive procedures for identifying prestress losses were mainly developed since serviceability and safety of Prestressed Concrete (PC) girders depend on the effective state of prestressing. In fact, substantial long term prestress losses can induce excessive deflections and cracking in large span PC bridge girders. However, old unsolved problematics as well as new challenges exist since a variation in prestress force does not significantly affect the vibration responses of such PC girders. As a result, this makes uncertain the use of natural frequencies as appropriate parameters for prestress loss determinations. Thus, amongst emerging techniques, static identification based on vertical deflections has preliminary proved to be a reliable method with the goal to become a dominant approach in the near future. In fact, measured vertical deflections take accurately and instantaneously into account the changes of structural geometry of PC girders due to prestressing losses on the equilibrium conditions, in turn caused by the combined effects of tendon relaxation, concrete creep and shrinkage, and parameters of real environment as, e.g., temperature and relative humidity. Given the current state of quantitative and principled methodologies, this paper represents a state-of-the-art review of some important research works on determining prestress losses conducted worldwide. The attention is principally focused on a static nondestructive method, and a comparison with dynamic ones is elaborated. Comments and recommendations are made at proper places, while concluding remarks including future studies and field developments are mentioned at the end of the paper.

Wind Tunnel Studyon Vortex-Induced Vibration Characteristics of Long-Span Suspension Bridges with Single Cable Plane

2014 ◽  
Vol 633-634 ◽  
pp. 1263-1266
Author(s):  
Huang Yu
Keyword(s):  
Wind Tunnel ◽  
Suspension Bridge ◽  
Wind Tunnel Experiment ◽  
Vibration Characteristics ◽  
Torsional Stiffness ◽  
Suspension Bridges ◽  
Vortex Induced Vibration ◽  
Long Span Bridges ◽  
Wind Speeds ◽  
Long Span

For modern long-span bridges, both the optimization of aerodynamic shape and the increase of torsional stiffness according to the result of the wind tunnel experiment could avoid the flutter instability.Vortex-inducedvibration with relatively large amplitude happens easily at low wind speeds. In this paper, based on wind tunnel experiment, by studying on the vortex-induced vibration characteristics of a long-span suspension bridge with single cable plane, aerodynamic measures for easing the vortex-induced vibration are given.

The Seismic Response Analysis Method of the Jacket under Multiple Support Excitation

2012 ◽  
Vol 256-259 ◽  
pp. 2051-2055
Author(s):  
Jian Mei Sun ◽  
Hao Cui
Keyword(s):  
Seismic Analysis ◽  
Response Analysis ◽  
Analysis Method ◽  
Seismic Response Analysis ◽  
Oil Reserves ◽  
Long Span ◽  
Simplified Method ◽  
Multiple Support ◽  
Support Excitation ◽  
Offshore Oil

With the development of demand of exploiting offshore oil reserves, the Jacket platform structure’ span and depth is more and more large, so the seismic analysis of the jacket structure will become more and more complicated. In the dynamic analysis of long-span structures, multiple support excitation may be accounted is necessary. For big jacket structure, it is more accurate and reasonable by multiple support excitation than by uniform excitation. The objective of the research described herein is to develop a simplified method to investigate the effect of multiple support excitation on the jacket structure.

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