Bracing in completed composite box girder bridges

1984 ◽  
Vol 11 (4) ◽  
pp. 967-977 ◽  
Author(s):  
F. A. Branco ◽  
R. Green
Keyword(s):  
Load Distribution ◽  
Experimental Studies ◽  
Box Girders ◽  
Box Girder Bridges ◽  
Box Girder ◽  
Linear Elastic ◽  
Finite Strip ◽  
Girder Bridges ◽  
Composite Bridges ◽  
Web Stiffeners

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.

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
Keyword(s):  
Radius Of Curvature ◽  
Curved Bridges ◽  
Box Girders ◽  
Box Girder Bridges ◽  
Cross Sectional ◽  
Box Girder ◽  
Horizontally Curved ◽  
Finite Strip ◽  
Girder Bridges ◽  
Bridge Models

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.

Bracing for composite box girder bridges

1984 ◽  
Vol 11 (4) ◽  
pp. 844-853 ◽  
Author(s):  
Fernando A. Branco ◽  
Roger Green
Keyword(s):  
Torsional Stiffness ◽  
Scale Model ◽  
Box Girders ◽  
Box Girder Bridges ◽  
Box Girder ◽  
Finite Strip ◽  
Girder Bridges ◽  
Open Section ◽  
Box Beams ◽  
Construction Loads

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.

scholarly journals Investigation of Load Distribution Factors for Two-Span Continuous Composite Multiple Boxgirder Bridges

2021 ◽  
Author(s):  
Manal Ibrahim
Keyword(s):  
Load Distribution ◽  
Three Dimensional ◽  
Bending Moment ◽  
Box Girders ◽  
Box Girder Bridges ◽  
Box Girder ◽  
Girder Bridges ◽  
Truck Loading ◽  
Dimensional Finite Element ◽  
Three Dimensional Finite Element

Bridges formed of concrete deck slab over built-up steel-box girders are frequently used in bridge construction for their economic and structural advantages. Box girder bridges impose structural challenges to get the straining actions for the design of girders. The objective of this study is to determine the load distribution characteristics for continuous composite multiple–box girder bridges under CHBDC truck loading. An extensive parametric study was conducted using the three-dimensional finite element to evaluate the moment and shear distribution factors when bridges subjected to CHBDC truck loading. The parameters considered in this study are the span length, number of lanes and number of boxes. Then, simple empirical formula for the bending moment and shear force were developed for the structural design. Correlation of the developed expressions based on FEA results with available CHBDC and AASHTO-LRFD formula showed that the former allow engineers to design such bridges more economically and reliably.

scholarly journals Investigation of Load Distribution Factors for Two-Span Continuous Composite Multiple Boxgirder Bridges

2021 ◽  
Author(s):  
Manal Ibrahim
Keyword(s):  
Load Distribution ◽  
Three Dimensional ◽  
Bending Moment ◽  
Box Girders ◽  
Box Girder Bridges ◽  
Box Girder ◽  
Girder Bridges ◽  
Truck Loading ◽  
Dimensional Finite Element ◽  
Three Dimensional Finite Element

Bridges formed of concrete deck slab over built-up steel-box girders are frequently used in bridge construction for their economic and structural advantages. Box girder bridges impose structural challenges to get the straining actions for the design of girders. The objective of this study is to determine the load distribution characteristics for continuous composite multiple–box girder bridges under CHBDC truck loading. An extensive parametric study was conducted using the three-dimensional finite element to evaluate the moment and shear distribution factors when bridges subjected to CHBDC truck loading. The parameters considered in this study are the span length, number of lanes and number of boxes. Then, simple empirical formula for the bending moment and shear force were developed for the structural design. Correlation of the developed expressions based on FEA results with available CHBDC and AASHTO-LRFD formula showed that the former allow engineers to design such bridges more economically and reliably.

Strengthening of box girder bridges with external prestressing - case study for the Langeland Bridge.

2021 ◽  
Author(s):  
Ulrik Sloth Andersen
Keyword(s):  
Additional Analysis ◽  
Box Girders ◽  
Box Girder Bridges ◽  
Box Girder ◽  
Basic Principles ◽  
Structural Assessment ◽  
South Eastern ◽  
Girder Bridges ◽  
External Prestressing

<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>

Design of segmental box girder bridges with match cast dry joints in Melbourne, Australia

2021 ◽  
Author(s):  
Adam McManus ◽  
Daniel Tofful ◽  
Rafal Wozniak
Keyword(s):  
Recent Work ◽  
Level Crossing ◽  
Box Girders ◽  
Design Standards ◽  
The West ◽  
Box Girder Bridges ◽  
Box Girder ◽  
Girder Bridges ◽  
Linear Infrastructure ◽  
Current Standards

<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>

scholarly journals Numerical Analysis of Temperature Influence on Transverse Cracks in Concrete Box-Girder Bridges

2020 ◽  
Vol 2020 ◽  
pp. 1-11
Author(s):  
Hanzheng Xu ◽  
Xiaofeng Yan
Keyword(s):  
Numerical Analysis ◽  
Highway Bridges ◽  
Hydration Reaction ◽  
Box Girders ◽  
Transverse Cracks ◽  
Box Girder Bridges ◽  
Box Girder ◽  
Girder Bridges ◽  
Concrete Box Girder ◽  
Concrete Box Girder Bridges

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.

The Twelve Mile Creek bridges—Design and construction

1984 ◽  
Vol 11 (4) ◽  
pp. 771-781 ◽  
Author(s):  
O. E. Ramakko
Keyword(s):  
Concrete Bridge ◽  
Box Girders ◽  
Box Girder Bridges ◽  
Box Girder ◽  
Horizontal Alignment ◽  
Girder Bridges ◽  
Deck Slabs ◽  
Posttensioned Concrete ◽  
Concrete Box Girder Bridges ◽  
Design And Construction

The two bridges featured are precast segmental concrete box girders built by the balanced cantilever method. Crossing a hydro tailrace, this $11 million project forms a part of the new Highway 406 through St. Catharines, Ontario. Several unique features of the structures are highlighted. These features include transverse rib beams employed at each segment face to support the deck slab; flaring of the deck slabs to accommodate on and off ramps; and twisting horizontal alignment of the highway. Both bridges have a depth-to-span ratio of 1:27, which results in one of the most slender precast box girder bridges built by the balanced cantilever method. The construction phase of this project is reviewed with particular attention to the casting operation and to the erection of the segments employing a steel launching truss. Design- and construction-related problems encountered are presented and reveal that the more perplexing problems are generally those not related to the complexities of the segmental form of construction but rather to the more mundane aspects of posttensioned concrete bridge construction. Key words: precast segmental concrete box girder bridges, balanced cantilever methods, steel launching truss, short line casting bed.

EXPERIMENTAL EVALUATION OF PIPE-SHAPE SHEAR CONNECTORS FOR MULTI-BEAM BOX GIRDER BRIDGES

2015 ◽  
Vol 2 (1) ◽  
Author(s):  
Won-Ho Heo ◽  
Chi-Young Jung ◽  
Hyun-Min Lee ◽  
Sang-Hyo Kim
Keyword(s):  
Experimental Evaluation ◽  
Box Girders ◽  
Box Girder Bridges ◽  
Box Girder ◽  
Shear Connectors ◽  
Girder Bridges ◽  
Pull Out ◽  
Shear Keys ◽  
Integration Effect ◽  
Push Out

This study mainly focused on the experimental evaluation of pipe-shape shear connectors for multi-beam box girder bridges. The multi-beam box girder bridges are a structure to the integration with the box girders placed adjacent to each other. They are generally connected by shear keys and loop joints to resist the shear force at their interfaces, and lateral tendons for applying the compression force. However, if the integration effect decreases with time, the relative deflection between adjacent girders occurs and it causes the reflective cracks on the deck along the interfaces. Furthermore, the efficiency of constructing multi-beam box girder bridges decreases when loop joints are used because it is complicated to form the required connections using couplers. Therefore, this study evaluated behavior of pipe-shape shear connectors which are superior in workability and ductility than loop joints by push-out tests and pull-out tests.

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