Experimental Study on Ultimate Behavior at Negative Moment Regions of Composite Bridges

2005 ◽  
Vol 1928 (1) ◽  
pp. 2-12
Author(s):  
Il-Sang Ahn ◽  
Methee Chiewanichakorn ◽  
Aaron F. Nottis ◽  
Jeffrey A. Carpenter ◽  
Stuart S. Chen ◽  
...  
Keyword(s):  
Plastic Hinge ◽  
Experimental Results ◽  
Steel Girder ◽  
Internal Support ◽  
Composite Bridges ◽  
Negative Moment ◽  
Composite Bridge ◽  
Factor Design ◽  
Load And Resistance Factor ◽  
Concrete Deck

This paper presents experimental results of the ultimate behavior of the negative moment region of a quarter-scale full model and a half-scale subassemblage model of a two-span continuous composite bridge of concrete deck slab on steel girder. The two specimens are based on a prototype bridge that has a large girder spacing [3,800 mm (13 ft)]. At the ultimate state, it is shown that a larger portion of the deck is activated to resist tensile stress compared with the effective width specified in the AASHTO load and resistance factor design bridge specifications. Also, a plastic hinge that forms at the internal support has enough rotational capacity (ductility) to enable development of a second plastic hinge within the span. Experimental results show a reasonably good match with accompanying finite element method analyses.

AASHTO’s Load and Resistance Factor Design Specifications for Transverse Braces: Adverse Effects on Integrity and Durability of Reinforced Concrete Deck Slabs

2000 ◽  
Vol 1740 (1) ◽  
pp. 118-125 ◽  
Author(s):  
Martin P. Burke ◽  
Joseph S. Seif
Keyword(s):  
Reinforced Concrete ◽  
Highway Bridges ◽  
Resistance Factor ◽  
Structural Systems ◽  
Steel Bridge ◽  
Design Specifications ◽  
Deck Slabs ◽  
Factor Design ◽  
Load And Resistance Factor ◽  
Concrete Deck

The transverse bracing provisions (diaphragms, cross-braces, crossframes, and so on) of the 1998 AASHTO load and resistance factor design (LRFD) bridge design specifications for the design of deck-type highway bridges are examined. This examination suggests that implementation of these provisions not only will have an adverse effect on the integrity and durability of reinforced concrete deck slabs, and consequently on life-cycle bridge costs; implementation of such provisions also has the potential to affect the desirability of steel bridge construction adversely. Instead of avoiding the use of midspan braces, as implied by LRFD provisions, it is urged that midspan braces be more generally recognized as primary elements of complex superstructure structural systems and thus be sized and spaced to function not only as transverse flange braces but also integrally with concrete deck slabs to distribute vehicular loads laterally. Such a practice not only will yield more efficient higher-quality structural systems capable of functioning effectively for 100 years or more, thus doubling their presently expected lives, but it will also help extend the service lives of the more vulnerable reinforced concrete deck slabs.

Methodologies for Evaluation of Effective Slab Width

2005 ◽  
Vol 1928 (1) ◽  
pp. 13-26
Author(s):  
Methee Chiewanichakorn ◽  
Amjad J. Aref ◽  
Stuart S. Chen ◽  
Il-Sang Ahn
Keyword(s):  
Finite Element ◽  
Concrete Slab ◽  
Slab Thickness ◽  
Steel Girder ◽  
Shear Connectors ◽  
Slab Width ◽  
Composite Section ◽  
Negative Moment ◽  
Load And Resistance Factor ◽  
Aashto Lrfd

A composite section is made up of a steel girder and concrete slab connected by shear connectors. The shear lag phenomenon usually takes place in such a section and results in underestimation of stresses and strains at the web-to-flange intersections of the girder. With the introduction of the concept of effective slab width, the actual width can be replaced by an appropriate reduced slab width. The classical effective slab width definition does not take into account the strain variation through the slab thickness. More sophisticated definitions are introduced and used with finite element analyses. The method of finite element modeling is discussed, and the model is successfully verified with experimental results. Parametric study is conducted to investigate the effective slab width for both positive and negative moment sections. The effective slab width is computed and compared with the current AASHTO load and resistance factor design (LRFD) specifications. The results demonstrate that full width can be used as the effective slab width in the design and analysis in most cases for the design and analysis of both positive and negative moment sections. The current AASHTO LRFD specifications are found to be conservative for configurations with widely spaced girders, especially in negative moment sections.

scholarly journals Assessment of Al-Sabtea Bridge under the Effects of Static Loadings

2018 ◽  
Vol 4 (11) ◽  
pp. 2680
Author(s):  
Ali Laftah Abbas ◽  
Qassim Yehya Hamood
Keyword(s):  
Steel Beams ◽  
Steel Girder ◽  
Shear Connectors ◽  
Applied Loading ◽  
Composite Girder ◽  
Composite Bridges ◽  
Composite Bridge ◽  
Bottom Face ◽  
Headed Stud ◽  
Steel Section

The behavior and strength of composite for composite bridges relay on the connectors that used to connect the steel beams or girders with reinforced concrete deck slab. Different type of shear connectors that available in the market such as headed stud or steel channels are commonly welded to the top face of the steel section to prevent slip at the interface between the two different materials. In present paper, existing composite bridge built in Iraq is modeled using finite elements approach by ANSYS. The bridge is simulate by adopt real dimensions and geometry to check out the performance of connectors and strengths of composite girder under worst static loading conditions proposed by general Iraqi Standard Specification for Road and Bridges such as track, knife and military loadings. The analysis results indicate that the three types applied loading show that all stresses within the acceptable limits and did not reach high values compared capacities of these materials according to the AASHTO ASD code. The maximum stress at bottom face of steel girder is 114.7 MPa and the maximum deflection is 59 mm these values within limits of code. 

Structural Integrity for Nuclear Power Plant Against Excessive Load on Design Extension Condition

2013 ◽  
Author(s):  
Daigo Watanabe ◽  
Kiminobu Hojo
Keyword(s):  
Nuclear Power ◽  
Structural Integrity ◽  
Safety Factors ◽  
Design Code ◽  
Acceptance Criteria ◽  
Integrity Assessment ◽  
Current Design ◽  
Factor Design ◽  
Excessive Load ◽  
Load And Resistance Factor

This paper introduces an example of structural integrity evaluation for Light Water Reactor (LWR) against excessive loads on the Design Extension Condition (DEC). In order to assess the design acceptance level of DEC, three acceptance criteria which are the stress basis limit of the current design code, the strain basis limit of the current design code and the strain basis limit by using Load and Resistance Factor Design (LRFD) method were applied. As a result the allowable stress was increased by changing the acceptance criteria from the stress basis limit to the strain basis limit. It is shown that the practical margin of the LWR’s components still keeps even on DEC by introducing an appropriate criterion for integrity assessment and safety factors.

Load and Resistance Factor Design Criteria for Connectors

1978 ◽  
Vol 104 (9) ◽  
pp. 1427-1441
Author(s):  
John W. Fisher ◽  
Theodore V. Galambos ◽  
Geoffrey L. Kulak ◽  
Mayasandra K. Ravindra
Keyword(s):  
Resistance Factor ◽  
Design Criteria ◽  
Factor Design ◽  
Load And Resistance Factor

Closure to “Load and Resistance Factor Design Criteria for Connectors”

1980 ◽  
Vol 106 (9) ◽  
pp. 1985-1986
Author(s):  
John W. Fisher ◽  
Theodore V. Galambos ◽  
Geoffrey L. Kulak ◽  
Mayasandra K. Ravindra
Keyword(s):  
Resistance Factor ◽  
Design Criteria ◽  
Factor Design ◽  
Load And Resistance Factor
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