Effects of Distortion on Strength of Curved I-Shaped Bridge Girders

2003 ◽  
Vol 1845 (1) ◽  
pp. 48-56
Author(s):  
James S. Davidson ◽  
Chai H. Yoo
Keyword(s):  
Highway Bridges ◽  
Steel Bridge ◽  
Behavioral Issues ◽  
Bridge Superstructures ◽  
Horizontally Curved ◽  
Initiation And Propagation ◽  
Live Loads ◽  
Analytical Research ◽  
Girder Bridge ◽  
Torsional Stability

The curved I-shaped plate girders used in bridges with curved alignment are subjected to forces that cause significant distortion of the cross section during construction and during application of live loads after the deck has hardened. Furthermore, the addition of curvature reduces the vertical bending stiffness, increases deflection nonlinearities, and changes stability characteristics of behavior. Although the design equations of the AASHTO Guide Specifications for Horizontally Curved Highway Bridges are formulated to address these behavioral issues, design and construction engineers often are not familiar with the difficulties curvature introduces and do not understand the relationship between distortion and deflection amplification with the design equations. Analytical research conducted as part of the FHWA Curved Steel Bridge Research Project was used to highlight and describe the effects of curvature on the strength and stability of curved I-girder bridge superstructures. Issues described include the following: ( a) effects of cross-frame and diaphragm spacing on system behavior, ( b) effects of curvature on the lateral-torsional stability of curved I-shaped beams, ( c) effects of warping stresses on flange buckling, ( d) effects of curvature on web behavior, and ( e) effects of curvature on initiation and propagation of yield stresses in the girders of curved I-girder frames.

scholarly journals The Response of a Highly Skewed Steel I-Girder Bridge with Different Cross-Frame Connections

2021 ◽  
Vol 11 (4) ◽  
pp. 7349-7357
Author(s):  
Y. Almoosi ◽  
N. Oukaili
Keyword(s):  
Cross Sections ◽  
Fatigue Cracks ◽  
Field Testing ◽  
Element Model ◽  
Horizontally Curved ◽  
Live Loads ◽  
The Cross ◽  
Strength And Stiffness ◽  
Girder Bridge ◽  
The Individual

Braces in straight bridge systems improve the lateral-torsional buckling resistance of the girders by reducing the unbraced length, while in horizontally curved and skew bridges, the braces are primary structural elements for controlling deformations by engaging adjacent girders to act as a system to resist the potentially large forces and torques caused by the curved or skewed geometry of the bridge. The cross-frames are usually designed as torsional braces, which increase the overall strength and stiffness of the individual girders by creating a girder system that translates and rotates as a unit along the bracing lines. However, when they transmit the truck’s live load forces, they can produce fatigue cracks at their connections to the girders. This paper investigates the effect of using different details of cross-frames to girder connections and their impacts on girder stresses and twists. Field testing data of skewed steel girders bridge under various load passes of a weighed load vehicle incorporated with a validated 3D full-scale finite element model are presented in this study. Two types of connections are investigated, bent plate and pipe stiffener. The two connection responses are then compared to determine their impact on controlling the twist of girder cross-sections adjacent to cross-frames and also to mitigate the stresses induced due to live loads. The results show that the use of a pipe stiffener can reduce the twist of the girder’s cross-section adjacent to the cross-frames up to 22% in some locations. In terms of stress ranges, the pipe stiffener tends to reduce the stress range by 6% and 4% for the cross-frames located in the abutment and pier skew support regions respectively.

The Ontario bridge code—Development and implementation

1984 ◽  
Vol 11 (4) ◽  
pp. 824-832
Author(s):  
R. A. Dorton
Keyword(s):  
Highway Bridges ◽  
Safety Index ◽  
Design Code ◽  
Limit States ◽  
Safety Level ◽  
New Development ◽  
Live Loads ◽  
Index Value ◽  
Correct Understanding ◽  
Short Time

The Ontario Highway Bridge Design Code was first issued in 1979 and has since been used for the design and evaluation of most bridges in Ontario. The code is in metric SI units, written in a limit states format, and calibrated to a target safety index value of 3.5. It has produced bridges with a more consistent safety level and capable of carrying design live loads twice those previously prescribed. Feedback from users was obtained and their concerns considered in formulating the provisions of the seeond edition in 1983. New bridge codes can be written in a short time and implemented most readily within a relatively small jurisdiction having control of all highways, bridges, and vehicles. Communications between the writers and potential users are important throughout the preparation and implementation phases. It is essential that a commentary volume be issued with a code to ensure correct understanding and interpretation of new provisions. Computer programs should be available, incorporating the code technology before the use of a new code becomes mandatory. Future code needs and likely areas of new development are outlined in the paper. Key words: calibration, codes, computer systems, highway bridges, loadings, safety, structures.

Intermediate Diaphragms Arrangement in Horizontal Curved Composite Box-Girder Bridge with Corrugated Webs

2011 ◽  
Vol 94-96 ◽  
pp. 326-331
Author(s):  
Jun He ◽  
Bin Han ◽  
Yu Qing Liu ◽  
Ai Rong Chen
Keyword(s):  
Normal Stress ◽  
Box Girder Bridges ◽  
Box Girder ◽  
Initial Curvature ◽  
Horizontally Curved ◽  
Girder Bridges ◽  
Torsion Effect ◽  
Corrugated Webs ◽  
Parametric Studies ◽  
Girder Bridge

Horizontally curved box girder bridges inherently exhibit complex torsional and distortional behavior as well as bending due to the initial curvature. As to the horizontal curved composite box-girder bridges with corrugated webs, diaphragms were arranged reasonably to reduce torsional and distortion effect for safety and stability due to the coupling of bending and torsion effect for initial curvature and reduced bending stiffness in horizontal direction for corrugated steel webs. Finite element models for a 3-spans continuous horizontal curved composite box girder bridges with corrugated webs were established. Comparing the ratio of warping normal stress to bending normal stress, the influence of the number and spacing for diaphragms on distortion control for curved bridges is investigated. Extensive parametric studies (including central angle, the aspect ratio of the box section, the spacing of the intermediate diaphragms)are performed and the design suggestions for the maximum spacing of the intermediate diaphragms are presented.

Load Test Analysis of Long-Span Prestressed Concrete Continuous Beam Bridge

2014 ◽  
Vol 1030-1032 ◽  
pp. 798-801
Author(s):  
Hua Su
Keyword(s):  
Bearing Capacity ◽  
Prestressed Concrete ◽  
Highway Bridges ◽  
Load Test ◽  
Beam Model ◽  
Test Analysis ◽  
Single Beam ◽  
Long Span ◽  
Continuous Beam Bridge ◽  
Girder Bridge

This paper takes a 45+60+45m prestressed concrete continuous box Girder Bridge as background, based on “Specification for Inspection and Evaluation of Load-bearing Capacity of Highway Bridges” (JTG/T J21-2011), single beam model and solid model are built for schematic design of load test. Compare the measured value and the theoretical value, and evaluate the bridge bearing capacity, finally provide technical base for project checking and accepting.

LOCAL CORROSION ENVIRONMENT AROUND CROSS SECTION OF A PLATE GIRDER BRIDGE

2017 ◽  
Vol 4 (1) ◽  
Author(s):  
Kazuto Maruyama ◽  
Seiya Kamasaki ◽  
Keiji Tajima ◽  
Toshihiko Aso
Keyword(s):  
Bottom Flange ◽  
Steel Bridge ◽  
Corrosive Environment ◽  
Water Leakage ◽  
Exposure Test ◽  
The Difference ◽  
Girder Bridge ◽  
One Year ◽  
A Site ◽  
Plate Girder

Corrosion is one of important factor for securing the safety of steel bridges. In general cases, the corrosive environment of the steel bridge is evaluated as a site environment. However, even in one bridge, the corrosive environment greatly varies from part to part. This research aims to clarify the difference of corrosion environment for each part of plate-girder-bridge which has three main girders. At this bridge, anti-freezing agent is sprayed in winter. On site measurements were performed on five points on each girder, which are both sides of web, both sides of upper/lower part of bottom flange. These measurements points include two points where water leakage is scattered. Temperature, humidity, amount of airborne salt and amount of adhering salt have been measured. In order to comprehensively assess corrosive condition, exposure test was also performed. Observations were carried out for one year. From measurement results, it became clear that temperature and humidity were not uniform at all observation points. These were differed at the inside and outside of girder and upper part and lower part of web. Amount of airborne salt to each girder is strongly influenced by anti-freezing agent. On the upper surface of the lower flange of each girder, there are places where corrosion markedly progresses due to deposits and water leakage.

Interaction of Blast Load on AASHTO Girder Bridge

2016 ◽  
Vol 857 ◽  
pp. 131-135
Author(s):  
G. Nikhil ◽  
N.I. Narayanan
Keyword(s):  
Highway Bridges ◽  
Standoff Distance ◽  
Blast Load ◽  
Structural Elements ◽  
Maximum Displacement ◽  
Explicit Finite Element ◽  
Analysis And Design ◽  
Finite Element Software ◽  
Girder Bridge ◽  
Blast Resistant Design

Guidelines of blast resistant design for AASHTO girder bridges have not taken up much importance on researches. As the transportation infrastructure mainly bridges are highly vulnerable for bomb attack, they must be designed to resist it. The analysis and design of bridges subjected to blast load requires a detailed understanding of blast propagation and its dynamic effects on various structural elements. The response of bridge components subjected to blast load is carried out using Abaqus explicit finite element software. The bridge is modeled on the basis of AASHTO-LRFD bridge design specification for highway bridges. Blast load has been introduced on different critical location of the bridge to understand their effects on various structural elements and extent of damage. A thorough parametric study varying standoff distance and TNT mass is done to understand their importance in developing a blast resistant design for AASHTO Girder Bridge. The study concludes that the value of maximum displacement decreases with the increase in standoff distance.

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