Design of horizontally curved composite box-girder bridges: a simplified approach

1995 ◽  
Vol 22 (1) ◽  
pp. 93-105 ◽  
Author(s):  
M. S. Cheung ◽  
S. H. C. Foo

Because of their excellent torsional capacity, box girders are used extensively in modern bridge construction having curved alignments. Applications of most design codes have been limited to bridges where the radius of curvature is much greater than the span length and cross-sectional dimensions. To meet the practical requirements arising during the design process, simple design methods are needed for curved bridges. This paper presents the results of a parametric study on the relative behaviour of curved and straight box-girder bridges and on the development of a simplified design method for the combined longitudinal moment of curved bridges. The combined moment includes the effects of flexure, torsion, and distortion. Three simply supported concrete-steel composite bridge models, including single-cell, twin-cell, and three-cell box girders and subjected to loadings as specified in the Ontario Highway Bridge Design Code, were analyzed using the finite strip method. The parameters considered in the study include types of cross section; types, locations, and magnitudes of loads; span lengths; and radius of curvature. Preliminary analysis of the results suggests that the behaviour of horizontally curved box-girder bridges is dependent on a variety of parameters, but most importantly on the span-to-radius ratio. Empirical relationships for combined longitudinal moment between curved and straight box-girder bridges are also proposed. Key words: bridge, curved, composite, design, finite strip.

2016 ◽  
Vol 857 ◽  
pp. 165-170
Author(s):  
Jefeena Sali ◽  
Regi P. Mohan

Box girders are now prominently used in freeway and bridge systems because of its structural efficiency, better stability, serviceability, economy of construction and pleasing aesthetics. Due to its high torsional rigidity box girders are most suited for curved bridges. In the present investigation, a comparative study of straight and curved box girder bridges with trapezoidal cross section has been carried out. The analysis is carried under the dead load, super imposed dead load, live load of IRC Class A tracked vehicle and prestressed load .This paper focus on the parametric study of box girders with different radius of curvature by keeping the span, cross sectional shape and material properties constant. The parametric investigations performed on curved box girders helps to evaluate the effects of change in radius of curvature on the behaviour of the box girders. This study would help the bridge engineers to better understand the behaviour of straight and curved box girder bridges. The results obtained from this study will be a valuable guidance to the bridge designers.


1984 ◽  
Vol 11 (4) ◽  
pp. 844-853 ◽  
Author(s):  
Fernando A. Branco ◽  
Roger Green

For steel–concrete composite box girder bridges, the steelwork is generally erected first and then the concrete deck cast. During construction the girder may be subjected to a variety of construction loads. If the girder is a flexible open section, and lacks distortional or torsional stiffness, the cross section will deform or twist excessively; such difficulties with box girder construction have been reported. Bracing systems should be installed to increase the torsional and distortional stiffness of the open section during construction. A finite strip analysis of the influence of bracing systems on open section box girders is presented and compared with test results obtained using a one-quarter scale model. With the analysis, the influence of ties, distortional bracing, torsion boxes, and top chord bracing on the behaviour of torsionally open box girders is examined. Simplified design methods are also presented whereby the bracing forces and the stresses arising from the distortion of the section can be computed. Key words: bridges (box girder), bridges (steel), box beams, torsional distortion, bending distortion, bracing, construction safety.


1984 ◽  
Vol 11 (4) ◽  
pp. 967-977 ◽  
Author(s):  
F. A. Branco ◽  
R. Green

During construction, bracing systems are included in box girders to prevent excessive distortion or twist of the sections. The influence of bracing on the deformation of composite bridges during service is examined. A linear elastic finite strip analysis was developed and results are compared with experimental studies from a model and a prototype bridge. The effectiveness of transverse web stiffeners and distortional bracing in preventing distortional stresses is studied. Transverse web stiffeners are effective in resisting distortion of completed girders, and distortional bracing is not essential for stiffened girders. For unstiffened girders, bracing is essential if additional longitudinal stresses due to distortion are not included in design. Interconnecting bracing between boxes is found to be effective in reducing transverse slab moments. Key words: bridges (box girder), bridges (composite), distortion, load distribution, web stiffening, bracing.


1998 ◽  
Vol 68 (5) ◽  
pp. 513-528 ◽  
Author(s):  
Dongzhou Huang ◽  
Ton-Lo Wang ◽  
M. Shahawy

2021 ◽  
Author(s):  
Ulrik Sloth Andersen

<p>This paper presents the basic principles for strengthening of bridges and other structures through the use of external prestressing. A case study that includes strengthening of the approach spans for the Langeland Bridge in the south-eastern part of Denmark is included.</p><p>During a recent rehabilitation, corrosion of the post-tensioned tendons was discovered inside the box girders of the bridge. Additional analysis of the extent of the corrosion and a structural assessment was undertaken. Based on this, a strengthening project was carried out, and strengthening with external prestressing is currently being implemented.</p>


Author(s):  
Adam McManus ◽  
Daniel Tofful ◽  
Rafal Wozniak

<p>A study of recent work undertaken on the Caulfield to Dandenong Level Crossing Removal Project and West Gate Tunnel Project in Melbourne Australia. The viaducts on these projects were precast segmental box girders erected span-by-span with match cast dry joints which present several key advantages in brownfield construction of linear infrastructure.</p><p>These case studies consider the application of Australian and International design standards to the design of Australian Infrastructure. It is acknowledged that international design standards such as AASHTO have moved away from the use of match cast dry joints however in the Australian context they are still relevant, and it has been necessary to interrogate current standards to establish a suitable design basis. This approach is imperative when assessing existing infrastructure like recent work on the West Gate Tunnel Project which involved the assessment of the existing precast segmental City Link Viaducts. This study seeks to present recommendations on how AS5100.5 may be modified to provide a more practical and efficient solution for the design of new and the assessment of existing infrastructure.</p>


2020 ◽  
Vol 2020 ◽  
pp. 1-11
Author(s):  
Hanzheng Xu ◽  
Xiaofeng Yan

Concrete box-girder bridges are widely used in China. During several routine inspections of two-year-old highway bridges of this type in the China Central Plains region, we found that transverse cracks are widespread on the bottom flanges of those box girders, mainly distributed in the area of 1/4L to 3/4L of the span. Selected cracks were then monitored continuously for one year. Our results showed that there had been no change in the widths of the cracks, but their lengths had increased and new cracks had formed. Taking into consideration factors like hydration reaction, relative humidity difference, shrinkage and creep, sunlight thermal differential effect, sudden temperature change, vehicle load, and their combined efforts, we have developed spatial structural models and conducted stress analyses on the reinforced concrete and prestressed concrete box-girder bridges, respectively. Our numerical analysis results indicated that the hydration reaction is the main reason for the initial bottom flange crack and the temperature difference between the inside and the outside of the box girders caused the crack developments at the later stage.


1979 ◽  
Vol 6 (1) ◽  
pp. 120-128
Author(s):  
Craig J. Miller ◽  
Juarez Accioly

Precast, prestressed segmental box-girder bridges are now accepted as an economical alternative for spans over 150 ft (46 m). Decisions about cross-sectional dimensions made during preliminary design can have a substantial influence on the final cost of the bridge. To help the designer obtain an economical starting point for a final design, a program was written to determine section dimensions and midspan and pier prestressing steel areas to give minimum cost. Since a preliminary design is obtained, the analysis techniques and design criteria have been simplified to reduce computation. The design produced by the program will satisfy AASHTO specification requirements and the recommendations of the PCI Bridge Committee. The optimization algorithm used is the generalized reduced gradient technique. To demonstrate the program capabilities, three example problems are discussed. The results indicate that optimum span-depth ratios are approximately 24 for the cost ratios used. The cost of the optimum design does not seem to be too sensitive to the ratio of concrete cost to prestressing steel cost.


2017 ◽  
Vol 22 (5) ◽  
pp. 881-901 ◽  
Author(s):  
Reihaneh Sarraf Shirazi ◽  
Gokhan Pekcan ◽  
Ahmad Itani

2011 ◽  
Vol 94-96 ◽  
pp. 326-331
Author(s):  
Jun He ◽  
Bin Han ◽  
Yu Qing Liu ◽  
Ai Rong Chen

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.


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