Finite element investigation of fibre-reinforced concrete deck slabs without internal steel reinforcement

1994 ◽  
Vol 21 (2) ◽  
pp. 231-236 ◽  
Author(s):  
Leon D. Wegner ◽  
Aftab A. Mufti
Keyword(s):  
Finite Element ◽  
Reinforced Concrete ◽  
Plain Concrete ◽  
Experimental Tests ◽  
Failure Criteria ◽  
Steel Reinforcement ◽  
Nonlinear Finite Element ◽  
Fibre Reinforced Concrete ◽  
Deck Slabs ◽  
Failure Loads

Experimental tests on half-scale models have demonstrated that polypropylene-fibre-reinforced concrete (PFRC) bridge deck slabs completely devoid of conventional steel reinforcement will fail by punching shear under concentrated loads considerably greater than those specified for design, provided the top flanges of the supporting girders are adequately restrained from moving laterally. Similar models were analyzed using nonlinear finite element techniques in order to reproduce experimentally observed load–deflection behaviours and failure loads. Commonly available concrete failure criteria for plain concrete was incorporated into the material model used for the PFRC deck slab. Results of the finite element analyses are presented. It is shown that while predicted load–deflection paths were less than satisfactory, accurate predictions of failure loads were achieved, but only after considerable tuning of various modelling parameters. Key words: nonlinear finite element method, bridge decks, fibre-reinforced concrete.

Analysis of reinforced concrete beams strengthened in flexure with composite laminates

1999 ◽  
Vol 26 (5) ◽  
pp. 646-654 ◽  
Author(s):  
C Nitereka ◽  
K W Neale
Keyword(s):  
Finite Element ◽  
Reinforced Concrete ◽  
Composite Laminates ◽  
Composite Structures ◽  
Composite Laminate ◽  
Concrete Beams ◽  
Steel Reinforcement ◽  
Nonlinear Finite Element ◽  
Reinforced Concrete Beams ◽  
Reinforced Composite

The structural behaviour of reinforced concrete beams strengthened in flexure by means of externally bonded fibre reinforced composite laminates is simulated numerically using a nonlinear finite element layered model. The full-bond assumption between the composite laminate, steel reinforcement, and the concrete is assumed, and shear deformations are neglected. Interlayer compatibility is achieved by imposing the same displacements at the interfaces of adjacent layers. The concrete is assumed to be nonlinear in compression and to exhibit a post-cracking tension-stiffening behaviour in tension. The behaviour of the steel reinforcement is modelled as elastic-plastic, while that for the composite laminate is linear elastic using an equivalent elastic modulus obtained from the so-called "classical lamination theory" of composite structures. An incremental, iterative displacement-control numerical analysis is developed. The finite element code is validated using published test results for conventional reinforced concrete beams, as well as for beams strengthened with composite laminates. A comparison of the numerical and experimental curves shows very good agreement. The effects of various parameters on the behaviour of composite-strengthened concrete beams are examined.Key words: reinforced concrete beams, fibre reinforced composite strengthening, nonlinear finite element analysis.

Deck slabs of skew girder bridges

1995 ◽  
Vol 22 (3) ◽  
pp. 514-523 ◽  
Author(s):  
Baidar Bakht ◽  
Akhilesh C. Agarwal
Keyword(s):  
Reinforced Concrete ◽  
Cross Section ◽  
Shear Failure ◽  
Highway Bridges ◽  
Steel Reinforcement ◽  
Fibre Reinforced Concrete ◽  
Girder Bridges ◽  
Deck Slabs ◽  
Concrete Deck ◽  
Deck Slab

Canadian codes allow the design of concrete deck slabs of slab-on-girder bridges by taking account of the internal arching action that develops in these slabs under concentrated wheel loads in particular. Provided that certain prescribed conditions are met, a deck slab is deemed to have met the design criteria if it is provided with a top and a bottom layer of steel reinforcement with each layer consisting of an orthogonal mesh of steel bars in which the area of cross section of the bars in each direction is at least 0.3% of the effective area of cross section of the deck slab. For deck slabs of bridges having skew angles greater than 20°, the codes require the minimum amount of reinforcement to be doubled in the end zones near the skew supports. Model testing has shown that need for such an increase can be eliminated by providing composite end diaphragms with high flexural rigidity in the horizontal plane. The proposed concept is tested on a model of fibre-reinforced concrete deck without steel reinforcement in which deficiencies in the confinement of the deck slab readily manifest themselves in form of a bending, rather than punching shear, failure. Key words: highway bridges, bridge decks, deck slabs, skew deck, skew bridges, fibre-reinforced concrete decks.

Nonlinear Finite Element Analysis of Corroded Reinforced Concrete Lock-Walls

2011 ◽  
Vol 101-102 ◽  
pp. 329-332
Author(s):  
Fu Lai Qu ◽  
Shun Bo Zhao ◽  
Zhi Mei Zhou ◽  
Baoan Yuan
Keyword(s):  
Finite Element ◽  
Reinforced Concrete ◽  
Finite Element Model ◽  
Concrete Strength ◽  
Element Model ◽  
Steel Reinforcement ◽  
Nonlinear Finite Element ◽  
Flexural Behavior ◽  
Element Analysis ◽  
Bond Slip

Reinforcement and concrete can work together to bear load in reinforced concrete structures, one of the main reasons is the relatively prefect bond between reinforcement and concrete. When steel reinforcement corrodes, the bond strength decreases and leads to the degradation of the reinforced concrete members. This paper built a finite element model by selecting appropriate stress-strain relationship of concrete and reinforcement, bond-slip relationship between concrete and corroded steel bars. The flexural behavior of corroded reinforced concrete lock-walls was analyzed by nonlinear finite element method. The calculated results were compared with the test results to verify the reliability of the finite element model. Finally, the influence of corrosion level of steel reinforcement and concrete strength on the normal section bearing capacity of lock-walls were discussed.

Experimental investigation of fibre-reinforced concrete deck slabs without internal steel reinforcement

1993 ◽  
Vol 20 (3) ◽  
pp. 398-406 ◽  
Author(s):  
Aftab A. Mufti ◽  
Leslie G. Jaeger ◽  
Baidar Bakht ◽  
Leon D. Wegner
Keyword(s):  
Reinforced Concrete ◽  
Concrete Slab ◽  
Steel Reinforcement ◽  
Punching Shear ◽  
Fibre Reinforced Concrete ◽  
Reinforced Concrete Slab ◽  
Shear Connectors ◽  
Deck Slabs ◽  
Concrete Deck ◽  
Deck Slab

It is now well established that concrete deck slabs of slab-on-girder bridges subjected to concentrated loads develop an internal arching system provided that certain conditions of confinement of the concrete are met. Because of this arching system, the deck slab, being predominantly in compression, fails in punching shear rather than in flexure. This aspect of deck slab behaviour, coupled with the corrosion problems associated with steel reinforcement in concrete, has prompted the authors to investigate the feasibility of fibre-reinforced concrete decks that are entirely devoid of steel. Through tests on a small number of half-scale models, it has been established that fibre-reinforced concrete slab with inexpensive non-ferrous fibres is indeed feasible, provided that the top flanges of the steel girders are connected just below the deck by transverse steel straps and the concrete deck is joined to the girders and diaphragms by shear connectors. The straps and shear connectors together provide the restraint necessary for development of the internal arching system in the slab, whilst the fibres control cracking due to the effects of shrinkage and temperature in the concrete. This paper describes the exploratory model tests and presents their results. Key words: deck slab, fibre-reinforced concrete, internal arching, punching shear, slab-on-girder bridge.

scholarly journals Fracture and Size Effect of PFRC Specimens Simulated by Using a Trilinear Softening Diagram: A Predictive Approach

Materials ◽  
2021 ◽  
Vol 14 (14) ◽  
pp. 3795
Author(s):  
Fernando Suárez ◽  
Jaime C. Gálvez ◽  
Marcos G. Alberti ◽  
Alejandro Enfedaque
Keyword(s):  
Reinforced Concrete ◽  
Size Effect ◽  
A Priori ◽  
Plain Concrete ◽  
Specimen Size ◽  
Bending Test ◽  
Orientation Factor ◽  
Fibre Reinforced Concrete ◽  
Softening Function ◽  
Three Point Bending

The size effect on plain concrete specimens is well known and can be correctly captured when performing numerical simulations by using a well characterised softening function. Nevertheless, in the case of polyolefin-fibre-reinforced concrete (PFRC), this is not directly applicable, since using only diagram cannot capture the material behaviour on elements with different sizes due to dependence of the orientation factor of the fibres with the size of the specimen. In previous works, the use of a trilinear softening diagram proved to be very convenient for reproducing fracture of polyolefin-fibre-reinforced concrete elements, but only if it is previously adapted for each specimen size. In this work, a predictive methodology is used to reproduce fracture of polyolefin-fibre-reinforced concrete specimens of different sizes under three-point bending. Fracture is reproduced by means of a well-known embedded cohesive model, with a trilinear softening function that is defined specifically for each specimen size. The fundamental points of these softening functions are defined a priori by using empirical expressions proposed in past works, based on an extensive experimental background. Therefore, the numerical results are obtained in a predictive manner and then compared with a previous experimental campaign in which PFRC notched specimens of different sizes were tested with a three-point bending test setup, showing that this approach properly captures the size effect, although some values of the fundamental points in the trilinear diagram could be defined more accurately.

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