Geometric imperfections and tolerances for steel box girder bridges

1988 ◽  
Vol 15 (3) ◽  
pp. 437-442 ◽  
Author(s):  
Eugene G. Thimmhardy ◽  
Robert M. Korol

An investigation to determine the magnitude of geometric imperfections induced during the fabrication of welded steel box girders is reported for nine highway bridges constructed in Canada. Measurement data were collected to compare the significance of dead load on initial imperfections obtained following fabrication. Existing bridges were found to have out-of-plane deviations of plate panels about 10% higher than unloaded bridge values. A statistical interpretation of measurements of initial plate imperfections and out-of-straightness of stiffeners culminates in tolerance levels, deemed to be appropriate for Canadian-built box girders, and well within the capability of the fabricating industry to achieve. Key words: box girder, bridges, field measurements, geometric imperfections, plate panels, stiffeners, structural steel, tolerances.

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.


1984 ◽  
Vol 11 (3) ◽  
pp. 377-386 ◽  
Author(s):  
R. M. Korol ◽  
E. G. Thimmhardy ◽  
M. S. Cheung

The degree of geometrical imperfections existing in the plate panels of six in situ steel box girder bridges located throughout Canada is reported. The purpose of a continuing investigation is to establish the extent to which strength and performance of Canadian box girders in multispan bridges are sensitive to imperfections. The 95% fractiles obtained from the imperfection measurements of webs and bottom flanges are shown to vary considerably from one bridge to another but, in general, tend to decrease with increasing plate thickness. Key words: bridges (box girder), field measurements, geometric imperfections, plate panels, structural steel.


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>


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.


1984 ◽  
Vol 11 (4) ◽  
pp. 771-781 ◽  
Author(s):  
O. E. Ramakko

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.


Author(s):  
Won-Ho Heo ◽  
Chi-Young Jung ◽  
Hyun-Min Lee ◽  
Sang-Hyo Kim

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.


2021 ◽  
Vol 1197 (1) ◽  
pp. 012047
Author(s):  
R. Manjula ◽  
A. Amrutha

Abstract Bridges based on box girders concept are extensively utilized for their cost saving solution for different passages & viaducts that are seen in the present day highway systems. The behavior of box girder bridges is analyzed for stresses in longitudinal and transverse directions. In this paper, analysis of three different box girders has been carried out using SAP2000 as per Indian Road Congress(IRC) provisions for rectangular and trapezoidal sections. The behaviors of box girders with uniform depth and varying widths have been analyzed. A parametric study is conducted for various parameters like bending moments, axial force & shear force using SAP2000.


2021 ◽  
Author(s):  
Anwar Androus

Due to their high torsional and wrapping stiffness as well as economic and aesthetic reasons, multi spine composite concrete-deck steel-box girder bridges became a very popular choice in highway bridges. Currently, North American Codes of Practice have recommended some analytical methods for the design of curved multiple-box girder bridges, providing a geometrically defined criterion to establish when horizontally curved may be treated as a straight bridge. To meet the practical requirements arising during the design process, a simple design method is needed for straight and curved composite box girder bridges in the form of load distribution factors. This study consisted of an experimental and a theoretical investigation. The experimental investigation included testing up-to-collapse three bridge models. While the theoretical investigation used a finite element software to examine the behavior of 225 different bridges to extract stress distribution factors for maximum bending stresses that occur at the mid span.


Author(s):  
Dongzhou Huang

This paper presents experimental and analytical impact factors for two existing curved steel box girder bridges. A Florida Department of Transportation test truck with a total weight of 468.8 kN applied the dynamic loading. The truck speed was incrementally increased from crawl to design speed. To evaluate the test results, the truck was simulated as a nonlinear vehicle model with 15 degrees of freedom. The bridge deck surface was assumed to be good and was simulated as a random process. Test and analytical results show that the impact factors of torsion are normally less than 30%, as are the impact factors of bending moment for bridges with span lengths less than 39 m. The impact factors of vertical shear are generally less than 15%, as are the impact factors of bending moment for bridges with span lengths greater than 50 m. The current AASHTO Guide Specifications for Horizontally Curved Highway Bridges appears to overestimate the dynamic loading of curved steel box girder bridges, especially for bridges with span lengths greater than 50 m. The research results are instructive and applicable to both bridge design and bridge load rating.


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