Interaction between the Local and General Zone for the Post-tensioned Girder Anchorage Zone

Background: The use of post-tensioning in girders causes high bearing and compressive stresses in the anchorage zone. In this study, the behavior of the anchorage zone and the interaction between the local and general zone are investigated. The variables included different reinforcements for both the local and general zones for a block of two anchorage devices. Methods: Both experimental and numerical methods have been applied to study the behavior of the anchorage zone. The experimental part of the study involved laboratory testing of sixteen specimens, and the numerical study was conducted using ABAQUS non-linear finite element analysis. Results: Tie reinforcement provided additional confinement for the local zone, and this confinement was more for the specimens with originally less confined spiral reinforcement strength. There was a slight or no effect of the local zone reinforcement on the general zone strength and ultimate load of the anchorage zone when the failure was in the general zone. Conclusion: Confinement of the local zone prevented the brittle bearing and compression failure of this zone.

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Comparative Numerical Study between /Steel Fiber Reinforced Concrete and SIFCON on Beam-Column Joint Behavior

Materials Science Forum ◽

10.4028/www.scientific.net/msf.1021.138 ◽

2021 ◽

Vol 1021 ◽

pp. 138-149

Author(s):

Ali Wathiq Abdulghani ◽

Abdulkhaliq A. Jaafer

Keyword(s):

Finite Element Analysis ◽

Finite Element ◽

Shear Failure ◽

Ultimate Load ◽

Numerical Study ◽

Load Capacity ◽

Fiber Reinforced Concrete ◽

Steel Fibers ◽

Steel Fiber Reinforced Concrete ◽

Element Analysis

This paper presents a nonlinear finite element analysis of RC beam-column joints. A numerical study carried out through a simulation on beam-column joints failed in flexure presented by experimental study. A verification procedure was performed on two joints by finite element analysis with ANSYS APDL. The verification with the experimental work revealed a good agreement through the load-displacement relationship, ultimate load, and displacement, and crack pattern. Also, the parametric study was implemented which including strengthening the concrete members by a variable ratio of steel fibers with normal ratios (0.5%, 1%, 1.5%, and 2%) and ratios of slurry infiltrated fiber concrete SIFCON (steel fibers up to 4%, 6%, and 8%) in addition to using of partial and full strengthening with and without stirrups. The test results revealed that steel fibers enhanced the flexural strength and ductility of the tested joint. Increase the ratio of steel fibers increased the flexural capacity by (101%, 153%, 177%, and 193%) for the four normal ratios of steel fibers respectively. SIFCON concrete ratios (4%, 6%m and 8%) enhanced ultimate strength by (521%, 802%, and 906%) respectively. The use of steel fibers reinforcement instead of steel rebar enhanced the ultimate load capacity by (101%) with large displacement. Full strengthening method by use of SIFCON presented pure flexural failure with cracks spread in the joint region but use the SIFCON concrete as a partial strengthening changed the failure mode to the shear failure.

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Fractographical Analysis and Biomechanical Considerations of a Tooth Restored With Intracanal Fiber Post: Report of the Fracture and Importance of the Fiber Arrangements

Operative Dentistry ◽

10.2341/15-262-s ◽

2016 ◽

Vol 41 (5) ◽

pp. E149-E158 ◽

Cited By ~ 4

Author(s):

VF Wandscher ◽

CD Bergoli ◽

IF Limberger ◽

TP Cenci ◽

P Baldissara ◽

...

Keyword(s):

Finite Element Analysis ◽

Finite Element ◽

Glass Fiber ◽

Shear Stresses ◽

Fiber Post ◽

Element Analysis ◽

Parallel Fibers ◽

Tooth Structure ◽

Anterior Teeth ◽

Compressive Stresses

SUMMARY Objective: This article aims to present a fractographic analysis of an anterior tooth restored with a glass fiber post with parallel fiber arrangement, taking into account force vectors, finite element analysis, and scanning electron microscopy (SEM). Methods: A patient presented at the Faculty of Dentistry (Federal University of Santa Maria, Brazil) with an endodontically treated tooth (ETT), a lateral incisor that had a restorable fracture. The treatment was performed, and the fractured piece was analyzed using stereomicroscopy, SEM, and finite element analysis. Results: The absence of remaining coronal tooth structure might have been the main factor for the clinical failure. We observed different stresses actuating in an ETT restored with a fiber post as well as their relationship with the ultimate fracture. Tensile, compression, and shear stresses presented at different levels inside the restored tooth. Tensile and compressive stresses acted together and were at a maximum in the outer portions and a minimum in the inner portions. In contrast, shear stresses acted concomitantly with tensile and compressive stresses. Shear was higher in the inner portions (center of the post), and lower in the outer portions. This was confirmed by finite element analysis. The SEM analysis showed tensile and compression areas in the fiber post (exposed fibers=tensile areas=lingual surface; nonexposed fibers=compression areas=buccal surface) and shear areas inside the post (scallops and hackle lines). Stereomicroscopic analysis showed brown stains in the crown/root interface, indicating the presence of microleakage (tensile area=lingual surface). Conclusion: We concluded that glass fiber posts with parallel fibers (0°), when restoring anterior teeth, present a greater fracture potential by shear stress because parallel fibers are not mechanically resistant to support oblique occlusal loads. Factors such as the presence of remaining coronal tooth structure and occlusal stability assist in the biomechanical equilibrium of stresses that act upon anterior teeth.

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