Bond Strength Testing and Simulation for Grouted Pile/sleeve Connections in Aged Structures

Abstract Recently the old accommodation platform (OAP) was decommissioned in Offshore Abu Dhabi. This platform was founded on four legs with piles inside and duly grouted inside pile and annulus. The main objective of this to carry out bond strength tests and finite element (FE) analysis for retrieved OAP grouted samples to investigate if any ageing effect on the bond strength of the grouted pile/sleeve connections for aged offshore structures. Nine Sleeve/Pile samples of varying lengths from 240mm to 1200mm were extracted for testing from the decommissioned platform. Dimensional analysis was carried out to assess the thickness loss and eccentricity. A bespoke testing rig with the maximum load capacity of 15,000kN was built at TWI Ltd. to perform bond strength tests. Finite element (FE) simulation of the testing was carried out and compared to the test results to calibrate and fine-tune material constitutive behaviour parameters and interfacial (friction and bond) parameters. Specimen measurements revealed a significant scatter in annulus grout thicknesses of various sleeve/pile specimens with maximum variations of up to 52%. These results indicate that pile alignment is strongly variable. Shear keys in the form of steel rings welded alternately onto the leg's inner surface and the pile outer surface providing mechanical resistance to relative sliding of the grout between the two bodies. The testing results shown that the ultimate loads varied significantly among various specimens, ranged between 9920kN for 1m specimen and 1800kN for 1.2m specimen. FE simulations agreed well with the observed failure modes and were used to investigate how the measured failure loads were influenced by grout material properties, cohesive bond behaviour and geometrical parameters such as shear keys and eccentricity. From the FE studies, it was found that different cohesive (surface) parameters are required to give the best fit, with the higher cohesive stiffness and strength associated with a higher failure load. Grout strength is also a significant parameter, but the effect of surface cohesion is less significant compared to material strength. The majority of the tested values were found to be meeting the minimum bond strength resulting from available standards (eg. ISO 19902). This type of real time testing output will provide insight into various parameters that contribute to bond strength in pile leg grouted connections. Moreover, these test and assessment results will form an integral and important input to various ongoing researches associated with ADNOC's grouted connections being carried out as part of another JIP led by National University of Singapore which is aimed at deriving design equations applicable to grouted connections beyond codal limits.

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Load Testing to Collapse Limit State of Barr Creek Bridge

Transportation Research Record Journal of the Transportation Research Board ◽

10.3141/1696-49 ◽

2000 ◽

Vol 1696 (1) ◽

pp. 92-102 ◽

Cited By ~ 10

Author(s):

Nicholas Haritos ◽

Anil Hira ◽

Priyan Mendis ◽

Rob Heywood ◽

Armando Giufre

Keyword(s):

Finite Element ◽

Failure Modes ◽

Flexural Rigidity ◽

Load Capacity ◽

Limit State ◽

Dynamic Test ◽

Service Condition ◽

Flat Slab ◽

Testing Program ◽

Static Testing

VicRoads, the road authority for the state of Victoria, Australia, has been undertaking extensive research into the load capacity and performance of cast-in-place reinforced concrete flat slab bridges. One of the key objectives of this research is the development of analytical tools that can be used to better determine the performance of these bridges under loadings to the elastic limit and subsequently to failure. The 59-year-old Barr Creek Bridge, a flat slab bridge of four short continuous spans over column piers, was made available to VicRoads in aid of this research. The static testing program executed on this bridge was therefore aimed at providing a comprehensive set of measurements of its response to serviceability level loadings and beyond. This test program was preceded by the performance of a dynamic test (a simplified experimental modal analysis using vehicular excitation) to establish basic structural properties of the bridge (effective flexural rigidity, EI) and the influence of the abutment supports from identification of its dynamic modal characteristics. The dynamic test results enabled a reliably tuned finite element model of the bridge in its in-service condition to be produced for use in conjunction with the static testing program. The results of the static testing program compared well with finite element modeling predictions in both the elastic range (serviceability loadings) and the nonlinear range (load levels taken to incipient collapse). Observed collapse failure modes and corresponding collapse load levels were also found to be predicted well using yield line theory.

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PERFORMANCE OF AXIALLY LOADED TAPERED CONCRETE-FILLED STEEL COMPOSITE SLENDER COLUMNS

Journal of Civil Engineering and Management ◽

10.3846/13923730.2013.799094 ◽

2013 ◽

Vol 19 (5) ◽

pp. 705-717 ◽

Cited By ~ 1

Author(s):

Alireza Bahrami ◽

Wan Hamidon Wan Badaruzzaman ◽

Siti Aminah Osman

Keyword(s):

Finite Element ◽

Failure Modes ◽

Load Capacity ◽

Special Kind ◽

Nonlinear Analyses ◽

Composite Columns ◽

Finite Element Software ◽

Tapered Angle ◽

Steel Composite ◽

Slender Columns

This paper focuses on the performance of a special kind of tapered composite columns, namely tapered concrete-filled steel composite (TCFSC) slender columns, under axial loading. These efficient TCFSC columns are formed by the increase of the mid-height depth and width of straight concrete-filled steel composite (CFSC) slender columns, that is, by the enhancement of the tapered angle (from 0° to 2.75°) of the tapered composite columns from their top and bottom to their mid-height. To investigate the performance of the columns, finite element software LUSAS is employed to carry out the nonlinear analyses. Comparisons of the nonlinear finite element results with the existing experimental results uncover the reasonable accuracy of the proposed modelling. Nonlinear analyses are extensively performed and developed to study effects of different variables such as various tapered angles, steel wall thicknesses, concrete compressive strengths, and steel yield stresses on the performance of the columns. It is concluded that increasing each of these variables considerably enhances the ultimate axial load capacity. Also, enhancement of the tapered angle and/or steel wall thickness significantly improves the ductility. Moreover, confinement effect of the steel wall on the performance of the columns is evaluated. Failure modes of the columns are also presented.

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Study on flexural performance of prestressed glulam continuous beams under control influence

Journal of Wood Science ◽

10.1186/s10086-021-01980-w ◽

2021 ◽

Vol 67 (1) ◽

Author(s):

Lidan Mei ◽

Nan Guo ◽

Ling Li ◽

Hongliang Zuo ◽

Yan Zhao

Keyword(s):

Failure Modes ◽

Ultimate Load ◽

Mechanical Performance ◽

Load Capacity ◽

Steel Wire ◽

Material Strength ◽

Element Analysis ◽

Control Range ◽

Flexural Performance ◽

Continuous Beams

AbstractTraditional glulam beam connection mode has a weak ability to transfer bending moment, leading to insufficient joint stiffness and mostly in the form of simply supported beams. To make full use of material strength, a novel prestressed glulam continuous beam was proposed. On this basis, this paper put forward a new method to further improve the mechanical performance of the beams by controlling prestress. According to the estimated ultimate loads of the beams, six different control range values were formulated, and 12 continuous beams were tested for flexural performance. The effects of prestressing control on the failure modes, ultimate load capacity, and load versus deformation relationships of the glulam continuous beams were analyzed. The test results indicated that the flexural performance of the beams with prestressed control was significantly improved compared to the uncontrolled beams, the ultimate load was enhanced by 13.60%–45.11%, and the average steel wire stress at failure was increased from 70% of the designed tensile strength to 94%. Combined with the finite element analysis (FEA), the reasonable control range of the prestressed control continuous beams was18%–30% of the estimated ultimate load. The research in this paper can provide references for the theoretical analysis and engineering application of similar structures.

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Chitosan in different concentrations added to a two-step etch-and-rinse adhesive system: influence on bond strength to dentin

Brazilian Dental Science ◽

10.14295/bds.2017.v20i4.1461 ◽

2017 ◽

Vol 20 (4) ◽

pp. 55

Author(s):

Rafael Avellar de Carvalho Nunes ◽

Flávia Lucisano Botelho do Amaral ◽

Fabiana Mantovani Gomes França ◽

Cecilia Pedroso Turssi ◽

Roberta Tarkany Basting

Keyword(s):

Bond Strength ◽

Failure Mode ◽

Failure Modes ◽

Resin Composite ◽

Adhesive System ◽

Fracture Pattern ◽

Test Machine ◽

Microtensile Bond Strength ◽

Etch And Rinse ◽

Strength Tests

Objective: the aim of the present study was to evaluate the influence of adding different concentrations of chitosan to an experimental two-step etch-and-rinse adhesive system on the bond strength and failure mode to dentin. Material and Methods: thirty-two flat dentin surfaces were obtained from extracted human third molars and divided into four groups (n=8) for application of the adhesive systems: AD - conventional two-step adhesive system (Adper Single Bond 2); EXP – experimental two-step etch-and-rinse adhesive system; Chi0.2% - EXP with addition of 0.2% Chitosan; Chi0.5% - EXP with addition of 0.5% Chitosan. Resin composite build-ups were made and the composite/dentin specimens were sectioned to obtain rectangular beams with a bond area of approximately 1mm2. After 24 hours, the sticks were submitted to microtensile bond strength tests in a universal test machine. The fracture pattern was evaluated under a stereoscopic loupe at 40X magnification. Results: one-way analysis of variance showed that the type of adhesive system had no significant effect on the bond strength values (p = 0.142), showing the mean bond strength values (standard deviation), in MPa, for the groups as follows: AD=20.1 (5.4); EXP=16.6 (2.3); Chi0.2%=16.1 (2.8); Chi0.5%=16.9 (2.3). In all the groups there was predominance of cohesive fractures in dentin, representing 68 to 82% of the failure modes. Conclusion: the addition of 0.2 or 0.5% of chitosan had no influence on the bond strength and failure mode of an experimental two-step etch-and-rinse adhesive system to dentin.KeywordsChitosan; Dental Adhesives; Failure Mode; Microtensile Bond Strength.

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Residual Ultimate Strength of Steel Plates with Longitudinal Crack and Pitting Corrosion under Axial compression: Nonlinear Finite Element Method Investigations

Journal of Ship Production and Design ◽

10.5957/jspd.10190055 ◽

2020 ◽

pp. 1-12

Author(s):

Farzaneh Ahmadi ◽

Ahmad Rahbar Ranji

Keyword(s):

Finite Element ◽

Crack Length ◽

Ultimate Strength ◽

Failure Modes ◽

Great Influence ◽

Longitudinal Crack ◽

Nonlinear Finite Element ◽

Geometrical Parameters ◽

Rectangular Plates ◽

Element Analysis

The main aim of present study was to determine the ultimate strength of cracked and corroded plates under uniform in-plane compression. Corrosion is considered as pitting-type corrosion at one side of the plate with a central longitudinal crack. Nonlinear finite element analysis using commercial computer code, ANSYS, is used to determine the ultimate strength of deteriorated plates. Different geometrical parameters, including the aspect ratio (AR) and thickness of the plate, number of pits, pit depth-to-thickness ratio, and crack length, are considered. It is found that the AR of plates have great influence on the ultimate strength of cracked-pitted plates. Because of the position and orientation of the crack, the length of central longitudinal crack has no influence on ultimate strength reduction of cracked and cracked-pitted plates. The results show that regardless of the number of pits and crack length, in thin plates where buckling controls failure modes at ultimate strength, the number of pits has less influence on reduction of the ultimate strength than thick plates where yielding controls failure mode. Also it is concluded that in rectangular plates, arrangements of pits has more effect on reduction of the ultimate strength of cracked-pitted plates than the number of pits.

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Stress Concentration Factor of A Two-Planar Double KT Tubular Joint due to In-Plane Bending Loading in Steel Offshore Structures

MATEC Web of Conferences ◽

10.1051/matecconf/201817701006 ◽

2018 ◽

Vol 177 ◽

pp. 01006

Author(s):

Prastianto Rudi Walujo ◽

Hadiwidodo Yoyok Setyo ◽

Fuadi Ibnu Fasyin

Keyword(s):

Finite Element ◽

Stress Concentration ◽

Stress Concentration Factor ◽

Concentration Factor ◽

Element Model ◽

Offshore Structures ◽

Geometrical Parameters ◽

Offshore Structure ◽

Wide Range ◽

Tubular Joint

The purpose of this study is to investigate the proper Stress Concentration Factor (SCF) of a 60° two-planar DKT tubular joint of a tripod wellhead offshore structure. So far, calculation of SCF for a multi-plane tubular joint was based on the formulation for the simple/uniplanar tubular joints that yield in over/under prediction of the SCF of the joint. This situation in turn decreasing the accuracy of fatigue life prediction of the structures. The SCF is one of the most important parameters in the tubular joint fatigue analysis. The tubular joint is modelled as finite element models with bending loads acting on the braces that cover a wide range of dimensionless geometrical parameters (β, τ, γ). The effect of such parameters on the SCF distribution along the weld toe of braces and chord on the joint are investigated. Validation of the finite element model has shown good agreement to the global structural analysis results. The results of parametric studies show that the peak SCF mostly occurs at around crown 2 point of the outer central brace. The increase of the β leads to decrease the SCF. While the increase of the τ and γ leads to increase the SCF. The effect of parameter β and γ on the SCF are greater than the effect of parameter τ.

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Effect of Coating Thickness on Bond Behaviors of Polymer Cement Coated Plain Steel Bar with Concrete and Finite Element Modeling

The Open Civil Engineering Journal ◽

10.2174/1874149501610010571 ◽

2016 ◽

Vol 10 (1) ◽

pp. 571-577 ◽

Cited By ~ 2

Author(s):

Xiong Yuanliang ◽

Wang Kunrong ◽

Liu Zhiyong ◽

Yang Zhengguang

Keyword(s):

Finite Element ◽

Bond Strength ◽

Coating Thickness ◽

Failure Modes ◽

Bond Behavior ◽

Finite Element Software ◽

Pullout Tests ◽

Steel Bar ◽

Contact Surfaces ◽

Hot Rolled

The pullout tests were carried out to investigate the effect of coating thickness on bond behavior (failure modes, bond strength, bond stress slip curves) between hot rolled plain steel bar (HPB) coated with polymer cement based coating and concrete. The results indicated the failure mode of the specimens is pullout. Suitable coating thickness could enhance the bond strength of steel bar embedded with concrete. By using contact surfaces with cohesive behavior in finite element software, the slip between coated plain steel bar and concrete can be realized. The results of numerical simulation are close to that of experiments, indicating that the model using contact surfaces with cohesive behavior can reasonably predict the results of pullout tests of HPB in concrete.

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Effect of Pressure on Collapse Behaviour of Stiffened Panel

Volume 4A: Structures, Safety and Reliability ◽

10.1115/omae2014-23498 ◽

2014 ◽

Author(s):

Lei Jiang ◽

Shengming Zhang

Keyword(s):

Finite Element ◽

Failure Modes ◽

Lateral Pressure ◽

Initial Pressure ◽

Offshore Structures ◽

Numerical Results ◽

Stiffened Panel ◽

Longitudinal Stress ◽

Stiffened Panels ◽

Hull Girder

During normal operations, ship and offshore structures, are subjected to combined lateral pressure and in-plane stresses. The effect of the lateral pressure is often ignored in hull girder ultimate assessments. This paper investigates the influence of the lateral pressures on the nonlinear collapse behavior of stiffened panels subjected to in-plane longitudinal stress. In this study, nonlinear finite element analyses were first conducted for the desired pressure alone; the longitudinal stress was then applied up to and beyond the collapse of the structures. Four representative stiffened panels taken from the bottoms of different double hull oil tankers were considered. The nonlinear analyses were performed using LR’s in-house finite element program VAST and following the procedure for nonlinear collapse analysis developed by LR. The numerical results indicated that the application of the initial pressure loads not only reduced the ultimate load carrying capacity of the panels significantly, but also changed the failure modes of the structures. The sensitivity of the ultimate strength to lateral pressure was dependent upon the panel geometry and whether the pressure was applied on the plate or the stiffener side. The numerical results and findings from this study are presented in this paper.

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Finite element method analysis of a spur gear with a corrected profile

The Journal of Strain Analysis for Engineering Design ◽

10.1243/03093247jsa284 ◽

2007 ◽

Vol 42 (5) ◽

pp. 281-292 ◽

Cited By ~ 9

Author(s):

A Pasta ◽

G Virzí Mariotti

Keyword(s):

Finite Element Method ◽

Finite Element ◽

Element Model ◽

Spur Gear ◽

Material Strength ◽

Mechanical Resistance ◽

Spur Gears ◽

The Difference ◽

Element Method

The difference between the stress value calculated by a two-dimensional finite element model of spur gears and those obtained by the rules in ISO 6336 was evaluated. Hertz theory, which provides information on the extension of the contact area and the maximum value of the contact pressure, was used to choose the dimensions of the elements. The mesh was created using the stress analytical solution relative to a model consisting of two cylinders in contact. Analogous optimization was executed for the mesh of the teeth feet; a mesh of 15 elements was considered optimum, because it minimized the difference to 0.5 per cent in the bending stress calculation. Stress values, obtained using the finite element method (FEM), are generally lower than those obtained with the ISO rules. Hence, this approach yields a conservative determination of the effective material strength. In all the examined cases, the difference was less than 2.5 per cent. The set FEM technique gives a result accuracy of better than 1 per cent; the difference between the stress obtained by FEM and those obtained by ISO 6336 is less than 2.5 per cent, so that the FEM confirmed, consistent with the ISO rules, that correction of the profile results in significant benefits with respect to determination of the mechanical resistance of spur gears.

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