@article {28917, title = {Cracked Continuum Modeling of Reinforced Concrete Elements under Impact}, volume = {Special Publication}, year = {2021}, pages = {85-105}, abstract = {Current computational modeling approaches used to evaluate the impact-resisting performance of reinforced concrete infrastructure generally consist of high-fidelity modeling techniques which are expensive in terms of both model preparation and computation cost; thus, their application to real-word structural engineering problems remains limited. Further, modeling shear, erosion, and perforation effects presents as a significant challenge, even when using expensive high-fidelity computational techniques. To address these challenges, a simplified nonlinear modeling methodology has been developed. This paper focuses on this simplified methodology which employs a smeared-crack continuum material model based on the constitutive formulations of the Disturbed Stress Field Model. The smeared-crack model has the benefit of simplifying the modeling process and reducing the computational cost. The total-load, secant-stiffness formulation provides well-converging and numerically stable solutions even in the heavily damaged stages of the responses. The methodology uses an explicit time-step integration method and incorporates the effects of high strain rates in the behavioral modeling of the constituent materials. Structural damping is primarily incorporated by way of nonlinear concrete and reinforcement hysteresis models and significant secondorder mechanisms are considered. The objective of this paper is to present a consistent reinforced concrete modeling methodology within the context of four structural modeling procedures employing different element types (e.g., 2D frames, 3D thick-shells, 3D solids, and 2D axisymmetric elements). The theoretical approach common to all procedures and unique aspects and capabilities of each procedure are discussed. The application and verification of each procedure for modeling different types of large-scale specimens, subjected to multiple impacts with contact velocities ranging from 8 m/s (26.2 ft/s) to 144 m/s (472 ft/s), and impacting masses ranging from 35 kg (77.2 lb) to 600 kg (1323 lb), are presented to examine their accuracy, reliability, and practicality.}, url = {https://www.utoledo.edu/engineering/faculty/serhan-guner/docs/JP19_Guner_et_al_2021_Impact.pdf}, author = {Serhan Guner and Trevor D Hrynyk and Andac Lulec} } @article {28918, title = {Shear-Resisting Performance of Reinforced Concrete Flat Plates with Different Headed Stud Layouts}, journal = {ACI Structural Journal}, volume = {118}, year = {2021}, pages = {5-16}, abstract = {The use of headed stud shear reinforcement has been widely accepted as an effective strategy to improve the punching shear resisting performance of reinforced concrete (RC) flat plates. However, the specific placement and layout of the shear studs provided in flat plates tends to vary throughout the world, and questions have been raised regarding the performance of the different shear stud layouts employed. This paper presents the results obtained from six large-scale flat-plate slab-column connection specimens that were tested under concentric shear loading conditions. The slabs were constructed with different flexural reinforcement ratios and employed headed stud rails placed in either a radial or cruciform configuration. The results showed that the use of shear studs provided in the cruciform or the radial shear stud layout greatly improved the shear-resisting behaviors of the slabs, and that the structural responses of the slabs employing the two different stud layouts were found to be comparable in nearly all respects.}, url = {https://search.proquest.com/openview/9177940bb68a6c4aa055996c087b0668/1?pq-origsite=gscholar\&cbl=36963}, author = {Gabriel E Polo and Oguzhan Bayrak and Trevor D Hrynyk} } @article {28885, title = {Acoustic emission monitoring of containment structures during post-tensioning}, journal = {Engineering Structures}, volume = {209}, year = {2020}, pages = {109930}, abstract = {This paper introduces a method based on acoustic emission (AE) to monitor the onset of delamination in post-tensioned concrete containment structures. The method is based on clustering AE occurring during post-tensioning and/or re-tensioning such structures. In particular, the investigation is focused on AE of a large-scale, curved concrete wall subject to monotonically increasing prestressing forces. This specimen is a representative of typical cylindrical concrete structures, such as water storage tanks, silos, bins, and nuclear containment structures. To analyze AE data, this paper uses both time-driven and hit-driven features extracted from AE. To this end, a novel approach is proposed to analyze and visualize hit-driven features. To detect and localize such defects, the proposed approach identifies an optimal number of clusters in AE data and interprets each cluster based on the physical mechanism that generates it. Such interpretations are compared with the state of stresses and modified Mohr{\textendash}Coulomb failure criteria. The results show that the AE events are due to three categories of source mechanisms, micro shear cracking, micro tensile cracking, and macro delamination cracking. To validate the results, comparisons are made with through-thickness expansion measurements of the wall. The results demonstrate that the proposed approach can detect delamination defects and enable decision makers to take remedial and preventive actions.}, url = {https://www.sciencedirect.com/science/article/abs/pii/S0141029619318176}, author = {Arvin Ebrahimkhanlou and Jongkwon Choi and Trevor D Hrynyk and Salvatore Salamone and Oguzhan Bayrak} } @article {28899, title = {Crack-based shear strength assessment of reinforced concrete members using a fixed-crack continuum modeling approach}, journal = {Journal of Structural Engineering}, volume = {146}, year = {2020}, pages = {04020024}, abstract = {

With the inventory of aging and deteriorating concrete infrastructure continuing to grow throughout much of North America and other regions of the world, there is a need for cost-effective tools that can provide meaningful assessments regarding structural damage. This paper presents a crack-based analysis procedure that can be used to estimate the residual shear strength of cracked reinforced concrete beam-type elements, based on a member-idealized, fixed-crack-continuum analysis procedure. Easy-to-obtain concrete crack measurements, which serve as input, are used in combination with basic material mechanical properties, member geometry and detailing, and cracked concrete dedicated behavioral modeling to provide estimates of the residual/remaining member shear capacity and to forecast critical shear crack widths to be referenced in future inspection and monitoring efforts. The fixed-crack continuum modeling approach is presented in a manner that can accommodate transverse confining stresses stemming from disturbed regions and relevant to the analysis of reinforced concrete beams. Two different procedure solution methods were investigated: one employing an assumption regarding the longitudinal stress acting on the idealized element and one using an estimate of average longitudinal strain based on known loading proportions. Data pertaining to 48 different beam specimens, comprising five different experimental programs documented in the literature, were employed for validation. The results presented in this paper demonstrate that even with the use of easy-to-obtain crack data and simple cracked-concrete modeling techniques, crack-based assessment procedures can be used to provide meaningful structural performance assessment data for existing concrete infrastructure.

}, url = {https://ascelibrary.org/doi/abs/10.1061/\%28ASCE\%29ST.1943-541X.0002564}, author = {Jarrod Zaborac and Apostolos Athanasiou and Salvatore Salamone and Oguzhan Bayrak and Trevor D Hrynyk} } @article {28915, title = {Delamination Cracking Behavior of Curved Post-Tensioned Concrete Structures}, journal = {ACI Structural Journal}, volume = {117}, year = {2020}, pages = {169-183}, abstract = {To investigate the underlying mechanisms of delamination cracking behavior in cylindrical post-tensioned concrete structures, three quarter-circle post-tensioned concrete wall assemblies were constructed and tested to delamination failure under monotonically increasing prestressing loads. The two main testing variables comprising the experimental program were specimen size (wall height, wall thickness, and cylinder radius) and the maximum nominal aggregate size. To compare the test results obtained, a size parameter, which represents the relative size of the wall specimen with respect to the maximum concrete aggregate size, was employed and found that characteristics of wall delamination responses were highly correlated with the specimen size parameter. The idealized through thickness and vertical responses proposed in this paper could be used as a guideline for the design, evaluation, repair, and strengthening of cylindrical post-tensioned concrete structures.}, url = {https://www.proquest.com/openview/b3a5cce9fe32a4487a7913087035b6b1/1?pq-origsite=gscholar\&cbl=36963}, author = {Jongkwon Choi and Clint R Woods and Trevor D Hrynyk and Oguzhan Bayrak} } @article {28920, title = {Image Scale Estimation Using Surface Textures for Quantitative Visual Inspection}, journal = {Journal of Computational Vision and Imaging Systems}, volume = {6}, year = {2020}, pages = {1-3}, abstract = {In this study, a learning-based scale estimation technique is proposed to enable quantitative evaluation of inspection regions. The underlying idea is that surface texture of structures (ie bridges or buildings) captured on images contains the scale information of the corresponding images, which is represented by pixel per physical dimension (eg, mm, inch). This allows training a regression model that provides a relationship between surface textures on images and their corresponding scales. Deep convolutional neural network is used to extract scale-related features from the texture patches and estimate their scales. The trained model can be exploited to estimate scales for all images captured from structure surfaces that have similar textures. The capability of the proposed technique is fully demonstrated using data collected from surface textures of three different structures and achieves an overall average scale.}, url = {https://whr.uwaterloo.ca/index.php/vsl/article/view/3541}, author = {Juan Park and Chul Min Yeum and Trevor Hrynyk} } @article {28922, title = {Learning-based image scale estimation using surface textures for quantitative visual inspection of regions-of-interest}, year = {2020}, abstract = {A major shortfall of vision-based inspection solutions is the lack of scale information, required to resolve inspection regions to a physical scale. To address this challenge, a learning-based scale estimation technique is proposed. The underlying assumption is that the surface texture of structures, captured in images, contains enough information to estimate scale for each corresponding image (e.g., pixel/mm). This permits the training of a regression model to establish the relationship between surface textures, captured in images, and scales. A convolutional neural network is trained to extract scale-related features from textures captured in images. Then, the trained model can be exploited to estimate scales for all images that are captured from a structure{\textquoteright}s surfaces with similar textures. The capability of the proposed technique is demonstrated using data collected from surface textures of three different structures. An average scale estimation error, from images of each structure, is less than 15\%.}, url = {https://onlinelibrary.wiley.com/doi/abs/10.1111/mice.12613}, author = {Ju An Park and Chul Min Yeum and Trevor D Hrynyk} } @article {28893, title = {A machine learning approach based on multifractal features for crack assessment of reinforced concrete shells}, journal = {Computer-Aided Civil and Infrastructure Engineering}, volume = {35}, year = {2020}, pages = {565-578}, abstract = {The geometric properties and spatial characteristics of crack patterns are significant indicators of the extent of damage on reinforced concrete structures. However, manual visual assessment is subjective and depends highly on the inspector{\textquoteright}s skills. The current study proposes an automated approach for the quantification of digitally documented crack patterns on reinforced concrete shell elements subjected to reversed cyclic shear loading. Multifractal analysis is proposed as a feature extractor for images depicting crack patterns and a set of artificial cracks is analyzed, to quantify how the properties of crack patterns vary as a function of cracking inclination. The results of the parametric study motivated the training of a multiclass classification model, which is used to provide damage level estimates for cracked reinforced concrete members. The training of the classifier is performed using experimental data of reinforced concrete shell elements under well-defined and idealized two-dimensional pure shear stress loading conditions. A dataset with 119 images from crack patterns of reinforced concrete shells is used for training. The multifractal features successfully translate the shape of the crack patterns into meaningful information about the extent of damage; achieving an overall test accuracy of 89.3\%.}, url = {https://onlinelibrary.wiley.com/doi/abs/10.1111/mice.12509}, author = {Apostolos Athanasiou and Arvin Ebrahimkhanlou and Jarrod Zaborac and Trevor Hrynyk and Salvatore Salamone} } @article {28919, title = {Nonlinear finite element analysis of reinforced concrete flat plate punching using a thick-shell modelling approach}, journal = {Engineering Structures}, volume = {224}, year = {2020}, pages = {111250}, abstract = {The punching shear resistance of reinforced concrete flat plates is an area where design is typically done in a highly-idealized manner, using provisions developed from experimental results of isolated slab-column connections; yet, involves structures where performance may be greatly impacted by system-level response. This paper presents the development and application of a practical thick-shell finite element-based nonlinear modelling procedure for reinforced concrete flat plate slab systems. Cracked concrete material modelling based on the formulations of the Disturbed Stress Field Model is employed in conjunction with computationally-efficient layered thick-shell finite elements that accommodate through-thickness shearing effects and are shown to be capable of capturing brittle punching-governed failure modes. A simple low-cost sectional analysis modification procedure is proposed to incorporate strength enhancements attributed to confining effects stemming from disturbances in slab-column connection regions. Load-displacement responses and failure modes developed using the proposed modelling procedure are shown to capture observed experimental responses and provide response estimates similar to those obtained using more costly three-dimensional solid continuum finite element modelling techniques. Finally, the analysis results presented were developed using simple-to-define concrete property input without the need for supplemental material model or analysis parameter calibration.}, url = {https://www.sciencedirect.com/science/article/abs/pii/S0141029620338517}, author = {Chong Yik M Goh and Trevor D Hrynyk} } @article {28921, title = {Structural performance assessment of a 60-year-old reinforced concrete bent cap}, journal = {Structural Concrete}, year = {2020}, abstract = {As the world{\textquoteright}s reinforced concrete (RC) civil infrastructure continues to age and exhibit visual signs of distress (e.g., cracking), the challenge of how to process this visual information is becoming increasingly important. While research is ongoing in this field, limited work has been done involving structures that are truly representative of real-world, aged civil infrastructure requiring assessment. Thus, this paper presents the results of an experimental program and subsequent numerical investigation into the performance of a diagonally cracked, RC bent cap that was removed from a 60-year-old bridge in Texas. Extensive work was done to document the cracking behavior and characterize the mechanical properties of the bent cap prior to ultimate load testing. The numerical investigation included both {\textquotedblleft}conventional{\textquotedblright} methods and nonlinear finite element analysis (with and without consideration of existing damage). Ultimately, the results of the experimental and numerical investigations suggest that, while the bent cap was exhibiting large-width shear cracks in service, the damage was not indicative of an impending shear failure.}, url = {https://onlinelibrary.wiley.com/doi/abs/10.1002/suco.202000033}, author = {Jarrod Zaborac and Bernardo Perez and Trevor Hrynyk and Oguzhan Bayrak} } @report {28937, title = {Acoustic Emission Monitoring of a Nuclear Containment Wall during Post-tensioning: Data Mining and Knowledge Discovery}, year = {2019}, abstract = {Post-tensioned containment structures are widely used in nuclear power plants. In case of any accident, these concrete structures are the last passive barrier against contaminating radioactive materials. During the construction-phase of these cylindrical concrete structures, hidden delamination defects may develop and remain undetected. This study introduces a new method based on acoustic emission (AE) to monitor the onset of delamination in a large-scale experimental model of a containment structure as it is being post-tensioned. In particular, advanced data processing algorithms are used to interpret AE data in terms of the delamination mechanism.}, url = {https://sites.tufts.edu/shmcasestudies/files/2019/06/SHMCaseStudy_EbrahimkhanlouArvinUTAustin.pdf}, author = {Arvin Ebrahimkhanlou and Jongkwon Choi and Trevor D Hrynyk and Salvatore Salamone and Oguzhan Bayrak} } @report {28924, title = {Data Mining For Acoustic Emission Monitoring Of A Nuclear Containment Wall During Post-tensioning}, year = {2019}, institution = {NC State University}, abstract = {This study introduces data mining for acoustic emission (AE) monitoring of containment structures. As being post-tensioned, hidden delamination cracks may develop in these structures and remain undetected. Since concrete cracking emits acoustic noises, advanced data mining techniques are here introduced to recognize common patterns in such AEs. Specifically, non-linear dimensionality reduction, k-mean clustering, and hidden Markov modelling are used. Validation performed on a large-scale, curved concrete wall shows, interpreting the physical meaning of AE patterns allows early detection of delamination.}, url = {https://repository.lib.ncsu.edu/bitstream/handle/1840.20/37734/SMiRT_25.pdf?sequence=1}, author = {Choi Jongkwon and Bayrak Oguzhan and Hrynyk Trevor and Ebrahimkhanlou Arvin and Salamone Salvatore} } @report {28923, title = {DELAMINATION BEHAVIOR OF CURVED POST-TENSIONED CONCRETE STRUCTURES}, year = {2019}, institution = {NC State University}, abstract = {The research presented in this paper was aimed at producing unique experimental data to gain insights into the effects of localized tensile stresses and delamination behavior in cylindrical post-tensioned concrete structures. Data of this sort is currently limited in the literature. Three curved post-tensioned concrete wall assemblies were constructed and tested to delamination failure. To investigate influences associated with specimen size and aggregate effects, all dimensions of Specimen 2 and Specimen 3 were double those of Specimen 1. While the reinforcement ratios were maintained, two different maximum aggregate sizes (3/8{\textquotedblright} for Specimen 1 and Specimen 2, 1{\textquotedblright} for Specimen 3) were used. The test results showed a specimen sizerelated influence on the onset of delamination cracking and delamination failures. The compressive stresses at the onset of delamination cracking were on the range of 0.09fc{\textquoteright}~0.24fc{\textquoteright}, which are lower than the allowable compressive stress limit for a service load condition, 0.35fc{\textquoteright}, specified in ASME BPVC (2017). Discussions regarding initiation of delamination cracking, sectional behavior during delamination cracking, and stress concentrations around the post-tensioning ducts are presented}, url = {https://repository.lib.ncsu.edu/bitstream/handle/1840.20/37808/SMiRT_25_Paper_Jongkwon_Choi1.pdf?sequence=1}, author = {Choi Jongkwon and Bayrak Oguzhan and Trevor Hrynyk} } @article {28906, title = {Evaluation of structural cracking in concrete}, year = {2019}, abstract = {Current methods used to assess structural cracking in concrete bridge infrastructure consist of various rating criteria in the form of pre-established concrete crack width and crack density limits. While cracking data obtained from routine inspections can aid in identifying bridge degradation, typical inspection techniques provide limited insight regarding the severity of structural distress. Further, inspection evaluation criteria are almost always independent of member-specific design details. The primary objective of this project was to develop crack-based strength assessment procedures that employ visual concrete crack data as input (e.g., measured crack widths, crack inclinations, crack patterns, etc.) and provide quantitative output related to bridge member health. Focus was given to developing procedures that require easy-to-obtain bridge member cracking data and the execution of low-cost analyses that can be performed using basic, and readily-available, software (e.g., MS-Excel or similar). Two different crack-based assessment procedures for in-service concrete bridge members were developed: i) a cracked continuum shear strength assessment procedure that is rooted in concepts of reinforced concrete mechanics and is used to examine shear-related distress in concrete bridge members, and ii) crack pattern quantification procedures that employ fractal analysis techniques to perform image-based assessments of crack patterns for the purpose of gaining insight into bridge member health. Research findings confirmed that diagonal crack widths, on their own, do not serve as reliable indicators of concrete member shear distress; however, mechanical modeling techniques that incorporate crack related input parameters can be used to conduct meaningful structural assessments for shear cracked bridge members. Further, the experimentally-validated cracked continuum assessment procedure can be used to develop member-specific crack inspection field aids to be employed on-site for the assessment of diagonal cracking in reinforced concrete bent caps.}, url = {https://rosap.ntl.bts.gov/view/dot/55742}, author = {Jarrod Zaborac and Apostolos Athanasiou and Salvatore Salamone and Oguzhan Bayrak and Trevor Hrynyk} } @article {28872, title = {Fractal and multifractal analysis of crack patterns in prestressed concrete girders}, journal = {Journal of Bridge Engineering}, volume = {24}, year = {2019}, pages = {04019059}, abstract = {

Description

This study investigated the fractal and multifractal characteristics of crack patterns observed in prestressed concrete girders. In particular, it focused on cracks that form in the end regions of prestressed girders during the fabrication phase and attributed to prestress transfer operations (i.e.,\ end-region cracks), and\ shear cracks\ that form due to subsequent structural (i.e., mechanical) loading. Synthetic crack patterns and experimental data collected during the fabrication and bending test of two large-scale girder specimens were used in this study. The results supported one of the key contributions of the study, which is using fractal analysis to quantify the extent of cracking that develops in prestressed concrete members. Another contribution of the study is that both fractal and multifractal analyses can be used to identify the development of different cracking mechanisms.

}, url = {https://ascelibrary.org/doi/abs/10.1061/(ASCE)BE.1943-5592.0001427}, author = {Arvin Ebrahimkhanlou and Apostolos Athanasiou and Trevor D Hrynyk and Oguzhan Bayrak and Salvatore Salamone} } @article {28925, title = {Modeling Damage and Failure in Pretensioned Concrete Girders Fabricated with Large-Diameter Strands}, journal = {Journal of Bridge Engineering}, volume = {24}, year = {2019}, pages = {04019073}, abstract = {Pretensioned concrete elements are commonly fabricated with strands 12.7 or 15.2 mm (0.5 or 0.6 in.) in diameter; however, the industry has seen interest in using larger-diameter strands in recent years. The use of larger-diameter strands results in greater transverse tensile stresses within the girder end regions, which may increase cracking at the time of prestress transfer. Such cracks may continue to grow during service and cause durability concerns. Moreover, increased damage around the strands and at the web{\textendash}flange interfaces may lead to unconventional failure mechanisms, such as anchorage-induced or horizontal shear failures. This paper introduces a modeling approach for investigating the performance of pretensioned girders fabricated with strands 17.8 mm (0.7 in.) in diameter from prestress transfer until failure under shear-critical loading. Data from seven full-scale prestress transfer tests and 10 load tests showed that the model can capture the transfer lengths, end-region stresses, and cracking at prestress transfer as well as load-deflection response and failure modes. Subsequently, three remedial end-region reinforcement details were investigated using the validated approach to examine their efficacy in controlling end-region cracks and stresses.}, url = {https://ascelibrary.org/doi/abs/10.1061/(ASCE)BE.1943-5592.0001440}, author = {Roya Alirezaei Abyaneh and Jessica Salazar and Alex Katz and Hyun su Kim and Hossein Yousefpour and Trevor Hrynyk and Oguzhan Bayrak} } @conference {28926, title = {REDUCED-COST MODELLING OF REINFORCED CONCRETE INFRASTRUCTURE UNDER HIGH-MASS LOW-VELOCITY IMPACT}, booktitle = {PROTECT 2019, 7th International Colloquium on Performance, Protection \& Strengthening of Structures Under Extreme Loading \& Events, Proceedings}, year = {2019}, pages = {173-185}, abstract = {The numerical assessment of reinforced concrete (RC) structures under impact is often done using high-fidelity modelling procedures. While such approaches can provide extremely detailed, high-resolution response estimates, in the majority of cases they have met with limited success for several reasons: i) they require complex micro-modelling of the structure under consideration, which entails significant model preparation and computation costs, ii) they often require characterization of difficult-to-define material parameters which are typically unknown and require calibration against test data, and iii) many of the commercial programs have shown deficiencies in their abilities to capture post-cracked concrete mechanical response, particularly for scenarios involving brittle failure mechanisms such as those governed by shear. This paper presents the application of an alternative RC shell and slab structure modelling approach. The nonlinear procedure employs low-cost layered shell finite elements that can capture throughthickness shearing effects, and models the mechanical response of concrete in accordance with the Disturbed Stress Field Model (DSFM): a smeared crack formulation dedicated to cracked RC elements. The modelling approach is used to develop response estimates for RC and steel fiber-reinforced concrete (SFRC) slab-like elements, and for an RC bridge railing subjected to high-mass low-velocity impacts. Using basic finite element meshing techniques and material behavioural models requiring easy-to-define parameters, good correlation between the observed and modelled responses were attained}, url = {https://www.researchgate.net/profile/Trevor-Hrynyk-2/publication/335880956_REDUCED-COST_MODELLING_OF_REINFORCED_CONCRETE_INFRASTRUCTURE_UNDER_HIGH-MASS_LOW-VELOCITY_IMPACT/links/5e21c82192851cafc38c6002/REDUCED-COST-MODELLING-OF-REINFORCED-CONCRETE-INFRAS}, author = {Trevor D Hrynyk and Frank J. Vecchio} } @conference {28894, title = {Detection of the onset of delamination in a post-tensioned curved concrete structure using hidden Markov modeling of acoustic emissions}, booktitle = {Sensors and Smart Structures Technologies for Civil, Mechanical, and Aerospace Systems 2018}, volume = {10598}, year = {2018}, pages = {1059821}, publisher = {International Society for Optics and Photonics}, organization = {International Society for Optics and Photonics}, abstract = {This paper presents acoustic emission (AE) monitoring of a large-scale curved, post-tensioned concrete wall under monotonically increasing prestressing loads. This structural system, which is commonly used in water storage tanks, silos, bins, and nuclear containment structures, is subject to hidden delamination defeats that may develop during posttensioning and lead to a premature brittle failure. To detect the onset of such defects, this study uses a network of AE sensors mounted on the outer surface of the wall and identifies common patterns in AE signals. Specifically, AE signals are clustered using k-mean clustering, and their sequence is modeled with a hidden Markov model. The comparison of the results with accurate through-thickness expansion measurements of the wall shows that certain patterns in AE signals are correlated with the onset of delamination, and thus can be used to detect it. This early detection of such delamination defects provides decision makers with sufficient time to take remedial and preventive action.}, url = {https://www.spiedigitallibrary.org/conference-proceedings-of-spie/10598/1059821/Detection-of-the-onset-of-delamination-in-a-post-tensioned/10.1117/12.2296624.short?SSO=1}, author = {Arvin Ebrahimkhanlou and Jongkwon Choi and Trevor D Hrynyk and Salvatore Salamone and Oguzhan Bayrak} } @report {28927, title = {End-Region Behavior and Shear Strength of Pretensioned Concrete Girders Employing 0.7-in. Diameter Strands}, year = {2018}, institution = {University of Texas at Austin}, abstract = {This report provides an overview of a comprehensive research project at The University of Texas at Austin on the end-region serviceability and shear strength of Texas pretensioned bulb-tee girders (Tx-girders) that employ 0.7-in. diameter strands on a 2- by 2-in. grid. Seven full-scale specimens were fabricated and tested at Ferguson Structural Engineering Laboratory. The detailing for mild-steel reinforcement in four specimens was identical to that currently used in Tx-girders with smaller-diameter strands whereas three girders were fabricated with modified end-region detailing. The specimens were extensively instrumented and monitored for transfer length as well as stresses and cracking within their end-regions at the time of prestress transfer. Greater end-region stresses and greater crack widths were detected in the specimens compared to girders with smaller-diameter strands. However, the greatest crack widths within the girder end regions were generally less than 0.007 in. Moreover, the specimens did not show unusual cracking patterns that trigger new concerns regarding the end-region serviceability of Tx-girders that employ 0.7-in. diameter strands. To investigate their load-carrying capacity and failure mechanisms, the specimens were later subjected to shear-critical loading until failure. Significant strand slip indicating anchorage-zone distress was detected in all specimens prior to reaching the peak applied load. However, widespread yielding of the shear reinforcement was also confirmed in all specimens, and the capacities of all specimens were conservatively estimated using the general method in AASHTO LRFD Bridge Design Specifications. It was also found that adding a cap bar to the bottom flange confinement reinforcement can significantly reduce the strand slip and increase the ultimate strength of the girder. The experimental program was supplemented by an extensive parametric investigation that provided insights into benefits and limitations of using 0.7-in. diameter strands and a series of computational simulations that aimed to shed light into mechanics of prestress transfer, failure modes, and effects of potential changes to end-region reinforcement in Tx-girders with 0.7-in. diameter strands.}, url = {https://rosap.ntl.bts.gov/view/dot/36671}, author = {Hossein Yousefpour and Hyun su Kim and Rodolfo Bonetti and Roya Alirezaei Abyaneh and Alex Katz and Alistair Longshaw and Jessica Salazar and Trevor Hrynyk and Oguzhan Bayrak} } @article {28897, title = {End-region behavior of pretensioned I-girders employing 0.7 in.(17.8 mm) strands}, journal = {ACI Structural Journal}, volume = {15}, year = {2018}, pages = {91-102}, abstract = {This paper presents an experimental study on transfer length, end-region cracking, and transverse end-region stresses in pretensioned concrete I-girders fabricated using 0.7 in. (17.8 mm) diameter strands on a 2 x 2 in. (51 x 51 mm) grid. The full-scale specimens consisted of two Tx46 and two Tx70 girders that were fabricated in a controlled laboratory environment using different strand patterns and concrete release strengths. The detailing for mild-steel reinforcement was done according to the current practice in Texas for girders with smaller-diameter strands. The measured 24-hour transfer lengths from the specimens exceeded estimates by both AASHTO LRFD and ACI 318-14 provisions. The observed crack widths in the specimens within 28 days after prestress transfer were generally limited to 0.007 in. (0.18 mm), indicating satisfactory performance for exposure to deicing chemicals according to ACI 224R guidelines. However, noticeably greater transverse forces were observed in the end regions of the specimens compared to the resistance required by AASHTO LRFD specifications.}, url = {https://www.researchgate.net/profile/Trevor-Hrynyk-2/publication/318538367_End-Region_Behavior_of_Pretensioned_I-Girders_Employing_07_in_178_mm_Strands/links/5a4e80670f7e9bbfacfc304e/End-Region-Behavior-of-Pretensioned-I-Girders-Employing-07-in-178-mm-Str}, author = {J Salazar and H Yousefpour and R Alirezaei Abyaneh and H s Kim and A Katz and T Hrynyk and O Bayrak} } @proceedings {28911, title = {End-region cracking in pretensioned concrete girders employing 0.7-in. strands: Time-dependent and service-load effects}, journal = {Proc., PCI 2018 Convention and National Bridge Conf. Chicago: PCI}, year = {2018}, abstract = {The use of 0.7-in. diameter strands instead of 0.5-or 0.6-in. diameter strands in pretensioned girders results in greater end-region stresses that can lead to cracking. End-region cracks, which might negatively affect the durability and strength of girders, develop at prestress transfer and change in length, width, and number over time and under applied loads. This paper investigates the effects of applied loads and timedependent volumetric changes of concrete on cracking conditions within the endregions of Texas bulb-Tee girders (Tx-girders) that employ 0.7-in. diameter strands on a 2-by 2-in. grid. A series of full-scale specimens was fabricated at Ferguson Structural Engineering Laboratory and was subjected to shear-critical loading at an age of 28 days or greater. The specimens were well-instrumented to estimate the endregion stresses at the time of prestress transfer. Crack widths and patterns, as well as prestress losses, were also monitored throughout the life of the specimens, including the duration of the shear tests. The number and width of cracks increased noticeably within the first three weeks after prestress transfer. However, the widths of most web cracks were reduced nearly by half under relatively small applied loads. The results provide valuable insight into acceptance limits for end-region cracks to ensure serviceable and durable pretensioned girders.}, url = {https://www.pci.org/PCI_Docs/Papers/2018/37_Final_Paper.pdf}, author = {H Kim and Rodolfo Bonetti and Alistair Longshaw and Hossein Yousefpour and Trevor Hrynyk and O Bayrak} } @article {28904, title = {Experimental and Numerical Assessment of Corbels Designed Based on Strut-and-Tie Provisions}, journal = {Journal of Structural Engineering}, volume = {144}, year = {2018}, pages = {04018138}, abstract = {Reinforced concrete (RC) corbels are short cantilever members that are used to transfer eccentric loads into columns or walls. Due to discontinuity in load and geometry, RC corbels cannot be adequately designed using methods that are based on beam theory. AASHTO LRFD Bridge Design Specifications permit the use of the strut-and-tie method (STM) for designing corbels. However, these specifications also require that the reinforcement details satisfy the requirements of an empirical design method, which prevents the efficient use of STM for such members. Moreover, the crack-control reinforcement requirements in the current STM provisions of AASHTO LRFD have been developed based on studies on deep beams, and the suitability of these provisions for corbels has not been investigated. This paper evaluates the behavior of reinforced concrete corbels designed according to the STM provisions of AASHTO LRFD. To do so, first, the performances of three full-scale corbel specimens designed according to STM were experimentally evaluated. Then, a numerical study using experimentally validated nonlinear finite-element models was conducted to investigate the crack-control reinforcement requirements for RC corbels. The results from the experimental study indicate that the STM provisions of the AASHTO LRFD provide conservative estimates of the load-carrying capacity of RC corbels; however, examination of the smeared node near the corbel-column interface, a check not currently required in AASHTO LRFD, is highly recommended. The results from the numerical study suggest that a reduction in the amount of secondary reinforcement currently required by AASHTO LRFD may be feasible, depending on the reinforcement layout used.}, url = {https://ascelibrary.org/doi/abs/10.1061/(ASCE)ST.1943-541X.0002137}, author = {Farid Khosravikia and Hyun su Kim and Yousun Yi and Heather Wilson and Hossein Yousefpour and Trevor Hrynyk and Oguzhan Bayrak} } @conference {28907, title = {MEASURING FRICTION LOSSES OF LARGE-ANGLE POST-TENSIONED CONCRETE WALLS}, booktitle = { PCI Convention and National Bridge Conference}, year = {2018}, abstract = {Friction losses in post-tensioned concrete structures can account for more than 50\% of the losses developed during prestressing operations. Accurate friction loss estimation is necessary for safe and economic design. Existing code equations and coefficients were developed in the 1950{\textquoteright}s and first introduced in the ACI 318 guidelines in 1963, and no significant changes have been made since. Further, these equations were derived based on small-angle assumptions and do not consider effects related to strand interaction for multi-strand post-tensioning applications. The use of these equations in large-angle post-tensioning applications, such as hoop post-tensioning in cylindrical structures, may lead to unrealistic estimations of friction losses. In this paper, friction loss measurements were compared with estimated losses computed on the basis of current theory. Three 90-degree wall specimens were fabricated, each comprised of four evenly-spaced ducts that contained multiple strands. To evaluate friction losses, both live-end and dead-end loads were measured over the course of the stressing operations. Anticipated friction losses were on the order of about 33\%; however, the measured losses were found to range from 40 to 60\%. The large-angle configuration and strand-interaction within the ducts were identified as probable causes for the larger-than-anticipated friction loss results obtained.}, url = {https://d1wqtxts1xzle7.cloudfront.net/64092833/FRICTION\%20TEST.pdf?1596533135=\&response-content-disposition=inline\%3B+filename\%3DMEASURING_FRICTION_LOSSES_OF_LARGE_ANGLE.pdf\&Expires=1625078033\&Signature=Cu5fyoSCfRvQb4aX6uwcHfpw8EKSN-FRK33TQUhIjPbnqXIWOwek}, author = {Jongkwon Choi and Clint R Woods and Trevor D Hrynyk} } @inbook {28928, title = {Modelling the Multi-directional Distribution of ASR-Induced RC Expansions}, booktitle = {High Tech Concrete: Where Technology and Engineering Meet}, year = {2018}, pages = {330-338}, publisher = {Springer, Cham}, organization = {Springer, Cham}, abstract = {Deterioration attributed to alkali-silica reaction (ASR) is plaguing concrete infrastructure throughout the world. While ASR development in new concrete construction is easily mitigated through the use of nonreactive aggregates, low-alkali cements, and/or supplementary cementitious materials, engineers are challenged to identify and manage ASR effects in existing structures. At present, the implications of ASR on the structural performance of existing structures remains an area of great uncertainty. With an increasing inventory of ageing concrete infrastructure, there is a growing need for practical tools that can be used to reliably assess the performance of ASR-affected structures. This paper presents a simple modelling procedure used to estimate the multiaxial distribution of ASR-induced expansions in reinforced concrete (RC) elements. The model is principally based on classical concepts of RC element strain compatibility, force equilibrium, and RC-relevant constitutive relations; however, the model has also been developed in light of experimental results obtained from a recently performed ASR-affected RC cube element monitoring study conducted by the same authors. An overview of the development and resulting formulation of the proposed modelling procedure is presented, and the model is verified against experimental data currently available in the literature. Using only basic, easily defined input parameters (e.g., the concrete modulus of elasticity), expansion distribution patterns for the RC cube elements, and ASR-affected elements monitored by other researchers, are generated and shown to provide high-accuracy estimates of experimental measurements with limited computational effort.}, url = {https://link.springer.com/chapter/10.1007/978-3-319-59471-2_40}, author = {David Wald and Trevor D Hrynyk and Oguzhan Bayrak} } @article {28884, title = {Numerical investigation of the punching resistance of reinforced concrete flat plates}, journal = {Journal of Structural Engineering}, volume = {144}, year = {2018}, pages = {04018166}, abstract = {Nonlinear finite-element analyses are used to numerically investigate the punching shear resistance of reinforced concrete flat plate structures. Material nonlinearity is based principally on the formulations of the disturbed stress field model, a smeared crack reinforced concrete modeling procedure. Low-cost three-dimensional solid finite elements and one-dimensional truss bar finite elements are used to represent concrete and steel reinforcement, respectively. Requiring only easily defined concrete material properties and employing fundamental finite-element meshing techniques, the modeling approach was found to provide good response estimates for slab{\textendash}column connection assembly tests under concentric shear loading conditions and was shown to effectively capture the effects of design parameters on slab punching shear performance: reinforcement ratio, column size, and slab thickness. The validated modeling approach was used to perform a brief numerical investigation on the effects of boundary conditions on the punching shear capacity of multibay flat plates. The results from the investigation were compared to the response obtained for an equivalent isolated slab{\textendash}column assembly specimen and to existing code provisions and two-way shear analysis procedures.}, url = {https://ascelibrary.org/doi/abs/10.1061/\%28ASCE\%29ST.1943-541X.0002142}, author = {Chong Yik M Goh and Trevor D Hrynyk} } @article {28905, title = {Application of an inclined shear reinforcing assembly for slab-column connections}, journal = {ACI SP}, volume = {321}, year = {2017}, pages = {7.1-7.20}, abstract = {

The performance of slab-column connections has been critically studied over the last several decades by researchers aiming to better understand the behavior of flat slabs subjected to punching shear loading conditions. As a result, the use of slab shear reinforcement has emerged as a practical strategy to improve both the strength and ductility of reinforced concrete flat slabs.

The primary objective of this research study was to investigate the behavior of reinforced concrete slab-column connections employing an inclined shear reinforcement system comprised of deformed steel reinforcing bars. Results are presented from an experimental program conducted at the Ferguson Structural Engineering Laboratory of The University of Texas at Austin. The tests were aimed at establishing the merits and limitations of the shear reinforcement system, and it was found that a premature failure attributed to inadequate shear reinforcement anchorage controlled the performance of the strengthened slabs. The performance of the slabs constructed with the inclined reinforcement system is compared to that of slabs reinforced with more conventional, vertically-oriented, shear reinforcement. Lastly, the influence of the observed anchorage-driven failures were examined in the context of estimated slab shear resistances developed from provisions and analysis methods currently available for reinforced concrete flat slabs.

}, url = {https://www.researchgate.net/profile/Trevor-Hrynyk-2/publication/320716385_Application_of_an_Inclined_Shear_Reinforcing_Assembly_for_Slab-Column_Connections/links/59f73f190f7e9b553ebed8c4/Application-of-an-Inclined-Shear-Reinforcing-Assembly-for-Slab-Colu}, author = {Mario Glikman and Gabriel Polo and Oguzhan Bayrak and Trevor Hrynyk} } @article {28873, title = {Behavior of Curved Post-Tensioned Concrete Structures without Through-Thickness Reinforcement}, journal = {ACI Structural Journal}, volume = {114}, year = {2017}, pages = {983-994}, abstract = {Two curved post-tensioned concrete wall assemblies were constructed and tested to delamination failure under monotonically increasing prestressing loads. In an effort to study the influence of size effect on the delamination failures observed, the nominal dimensions of the second specimen were twice those of the first, and the nominal reinforcement ratios of the two specimens were held constant. The data collected from the tests were used to investigate the underlying mechanics of the delamination failures observed and, to the authors{\textquoteright} knowledge, represent the first of their kind in open literature. The test results showed an apparent size effect on the delamination failures of the curved wall assemblies. Furthermore, the compressive stresses at the onset of the first delamination crack were found to be on the order of approximately 0.13fc' to 0.23fc', which is significantly lower than the stress limit of 0.35fc' permitted for service load conditions as specified in ACI 359-15. Finally, the friction losses based on ACI 343R were found to underestimate the measured friction losses by approximately 38 to 43\%.}, url = {https://www.researchgate.net/profile/Trevor-Hrynyk-2/publication/316903159_Behavior_of_Curved_Post-Tensioned_Concrete_Structures_without_Through-Thickness_Reinforcement/links/5950905a458515433839e455/Behavior-of-Curved-Post-Tensioned-Concrete-Structures-w}, author = {Jongkwon Choi and Clint R Woods and Trevor D Hrynyk and Oguzhan Bayrak} } @article {28895, title = {Benefits of using 0.7 in.(18 mm) diameter strands in precast, pretensioned girders: A parametric investigation}, journal = {PCI Journal}, volume = {62}, year = {2017}, pages = {59-75}, abstract = { This paper presents a parametric study on the benefits and limitations of using 0.7 in. (18 mm) diameter strands in precast, pretensioned concrete bridge girders. A validated parametric study tool was used to design a variety of girders with 0.5, 0.6, and 0.7 in. (13, 15, and 18 mm) diameter strands using different span lengths, concrete release strengths, and transverse spacings. The most noticeable benefit of 0.7 in. (18 mm) diameter strands over 0.6 in. (15 mm) diameter strands was found to be a reduction of up to 35\% in the number of strands.}, url = {https://www.pci.org/PCI_Docs/Publications/PCI\%20Journal/2017/November-December/Benefits_of_using_0.7\%20in._18_mm_diameter_strands_in_precast_pretensioned_girders_A_parametric_investigation\%20.pdf}, author = {Jessica Salazar and Hossein Yousefpour and Alex Katz and Roya Alirezaei Abyaneh and Hyun su Kim and David Garber and Trevor Hrynyk and Oguzhan Bayrak} } @article {28892, title = {Development and multiaxial distribution of expansions in reinforced concrete elements affected by alkali\–silica reaction}, journal = {Structural Concrete}, volume = {19}, year = {2017}, pages = {914-928}, abstract = {Understanding the development and multiaxial distribution of expansions is of critical importance in the appraisal of structures affected by alkali{\textendash}silica reaction. Such expansions were monitored for 33 480-mm reinforced concrete cubes in an effort to develop an improved understanding of the expansion mechanisms in reinforced concrete and broaden the database of experimental results available from which to build tools to aid in the performance assessment of affected structures. The cubes were fabricated using three different concrete mixtures of varying reactivity and contained uniaxial, biaxial, and triaxial reinforcement layouts with different reinforcement ratio combinations. In all cases, the cubes expanded at greater rates in unreinforced directions than in reinforced directions. Furthermore, the reinforcement ratios did not significantly influence expansion behavior, especially in the cases of uniaxially, equal biaxially, and equal triaxially reinforced specimens. Increasing the number of reinforced directions resulted in reduced volumetric expansion development over time and greater differences between expansions in reinforced and unreinforced directions. Cubes with end-anchored, deformed steel reinforcing bars placed in three layers developed expansions exceeding steel yield strains in all directions. Cubes with bars placed in two layers exhibited differential expansions between locally reinforced concrete regions at the edges of elements and unreinforced core regions. Mixture reactivity and environmental conditioning influenced expansion rates but not trends of the multiaxial distribution of volumetric expansions.}, url = {https://onlinelibrary.wiley.com/doi/abs/10.1002/suco.201600220}, author = {David M Wald and Morgan T Allford and Oguzhan Bayrak and Trevor D Hrynyk} } @article {28909, title = {End-Region Serviceability and Shear Strength of Precast, Pretensioned I-girders employing 0.7-in. diameter strands}, journal = {PCI/NBC, Cleveland, OH}, year = {2017}, url = {https://scholar.google.com/scholar?cluster=12548953588484048695\&hl=en\&oi=scholarr}, author = {H Kim and A Katz and J Salazar and R Abyaneh and H Yousefpour and T Hrynyk and O Bayrak} } @article {28916, title = {Experimental investigation of delamination behavior in curved post-tensioned concrete structures}, journal = {IASMiRT}, year = {2017}, abstract = {Research aimed toward understanding the underlying mechanics and behavior of curved posttensioned concrete structures subject to prestressing loads (eg, nuclear containment buildings, storage silos, and similar structures) is presented. Previous research focused on radial (ie, out-of-plane normal) stress development has been primarily analytical in nature and there is essentially no experimental research on this topic currently available in the open literature. This study is aimed at producing unique experimental data to gain insight into the effect of localized radial tensile stresses and concrete delamination behavior in curved post-tensioned structures. Three 90 curved post-tensioned concrete wall assemblies (referred to as Specimens 1, 2, and 3) were constructed and tested to delamination failure under monotonically increasing prestressing loads. In an effort to study the influence of wall size-effect, all dimensions of Specimen 2 were doubled those of Specimen 1. In Specimen 3, the size of the maximum aggregate was changed, while the dimensions and nominal design strength of the concrete were maintained. Test results showed a size-effect related influence on the delamination failure loads. Furthermore, it was revealed that the onset and propagation of the delamination cracking loads were affected by the radial stress concentration and specimen size factor. Delamination cracks for all specimens were initiated at compressive stresses which were lower than the allowable stress limit for a service load conditions specified in ASME BPVC Section III, Division 2.}, url = {https://repository.lib.ncsu.edu/bitstream/handle/1840.20/36080/SMiRT-24_06-04-05.pdf?sequence=1}, author = {Jongkwon Choi and Clint R Woods and Trevor D Hrynyk and Oguzhan Bayrak} } @article {30819, title = {High Tech Concrete: Where Technology and Engineering Meet}, journal = {Modelling the Multi-directional Distribution of ASR-Induced RC Expansions}, year = {2017}, author = {David Wald and Trevor D. Hrynyk and Oguzhan Bayrak} } @article {30825, title = {High Tech Concrete: Where Technology and Engineering Meet - Proceedings of the 2017 fib Symposium}, journal = {Modelling the multi-directional distribution of ASR-induced RC expansions}, year = {2017}, url = {http://www.scopus.com/inward/record.url?eid=2-s2.0-85025685865\&partnerID=MN8TOARS}, author = {Wald, D. and Hrynyk, T.D. and Bayrak, O.} } @article {30827, title = {IABSE Conference, Vancouver 2017: Engineering the Future - Report}, journal = {Toward practical modelling of reinforced concrete flat slab systems}, year = {2017}, url = {http://www.scopus.com/inward/record.url?eid=2-s2.0-85049621486\&partnerID=MN8TOARS}, author = {Goh, C.Y.M. and Hrynyk, T.D.} } @article {28898, title = {Modeling of Reinforced and Fiber-Reinforced Concrete Slabs under Impact Loads}, journal = {ACI SP}, volume = {321}, year = {2017}, pages = {8.1-8.20}, abstract = {Current modeling procedures used to investigate the performance of reinforced concrete structures under impact are almost entirely confined to hydrocode approaches (e.g., LS-DYNA). While such procedures are capable of providing highly detailed representations of reinforced concrete structures and elements, they have often met with limited success due to the fact that: i) they typically employ complex micro-modeling representations of the structure under consideration, which can be expensive in preparation and computation, ii) they often require extensive characterization of material properties which are typically unknown, or calibration against previous test data, and iii) many of the commercial programs have shown deficiencies in their abilities to adequately capture cracked concrete response, particularly with regard to brittle shear-governed behavior. This paper summarizes the application of an alternative modeling procedure for reinforced concrete slab and shell structures subjected to blast and impact loads. The nonlinear finite element program employed uses a layered thickshell element with reinforced concrete constitutive modeling done in accordance with the formulations of the Disturbed Stress Field Model (DSFM), a smeared rotating crack procedure shown to be capable of accurately capturing the behavior of shear-critical elements under conventional static loading conditions. This approach differs from that typically used within hydrocodes and results in comparatively simple model construction and reduced computation costs. The program is used to model the response of intermediate-scale reinforced concrete and steel fiber-reinforced concrete (SFRC) slab-like elements tested under repeated high-mass low-velocity impacts. Using simple finite element meshing techniques and predefined material behavioral models requiring only basic user input, good correlation between the observed and modeled slab response was attained.}, url = {http://vectoranalysisgroup.com/journal_publications/jp107.pdf}, author = {Trevor D Hrynyk and Frank J Vecchio} } @article {28900, title = {Shear Performance of Pretensioned Concrete I-Girders Employing 0.7 in.(17.8 mm) Strands.}, journal = {ACI Structural Journal}, volume = {114}, year = {2017}, pages = {1273-1284}, abstract = {An experimental program was conducted to study the effects of using 0.7 in. (17.8 mm) diameter prestressing strands on the performance of pretensioned concrete I-girders under shear-critical loading. Four full-scale Texas bulb-T girders (Tx-girders) with different concrete release strengths, member depths, shear span-depth ratios, and strand patterns were tested. The mild-steel reinforcement in the specimens was detailed according to the common practice in Texas for girders fabricated using conventional, smaller-diameter strands. All specimens exhibited considerable strand slip prior to failure. In three of the specimens, shear failure also resulted in prominent horizontal cracking at the interface between the web and the bottom flange. However, distributed yielding of the stirrups was confirmed in all specimens, indicating shear-tension failure. The capacities of all specimens were conservatively estimated using the general procedure in the AASHTO LRFD Bridge Design Specifications and the detailed method in ACI 318-14 provisions.}, url = {https://www.researchgate.net/profile/Trevor-Hrynyk-2/publication/318333551_Shear_Performance_of_Pretensioned_Concrete_I-Girders_Employing_07_in_178_mm_Strands/links/59b841af0f7e9bc4ca391a74/Shear-Performance-of-Pretensioned-Concrete-I-Girders-Employing-07}, author = {A Katz and H Yousefpour and H Kim and R Alirezaei Abyaneh and J Salazar and T Hrynyk and O Bayrak} } @article {28912, title = {Testing and Analysis of Two Deep Beams Designed Using Strut-and-Tie Method.}, journal = {ACI Structural Journal}, volume = {114}, year = {2017}, pages = {1531-1542}, abstract = {
The seventh edition of the AASHTO LRFD Bridge Design Specifications (2016 interim) includes revised provisions for the design of deep beams using the strut-and-tie method. The validity and accuracy of these provisions as applied to simply supported deep beams loaded in a manner that generates an inflection point between the supports was investigated in this research. As part of a course-related laboratory investigation, graduate students at the University of Texas at Austin used these provisions to design two reduced-scale deep beams. The specimens were subsequently constructed and tested. The experimental behaviors of the specimens including governing failure modes, load-displacement curves, and their ultimate capacities were investigated and compared with estimates developed from the strutand-tie method. The results obtained validated the suitability of the revised provisions for the design of deep beams with inflection points located between supports. Additionally, the students developed pre-test estimates for the behaviors and strengths of the two deep beam specimens using the finite element software program VecTor2. While there was some variation among the computed responses, the blind predictions accurately captured governing failure modes and provided reasonable capacity estimates.}, url = {https://www.researchgate.net/profile/Trevor-Hrynyk-2/publication/319597891_Testing_and_Analysis_of_Two_Deep_Beams_Designed_Using_Strut-and-Tie_Method/links/5a0a1da70f7e9bb949f96ee8/Testing-and-Analysis-of-Two-Deep-Beams-Designed-Using-Strut-and-Tie-Method}, author = {GA Martinez and KS Beiter and AR Ghiami Azad and GE Polo and RL Shinn and TD Hrynyk and O Bayrak} } @article {30826, title = {Toward Practical Modelling of Reinforced Concrete Flat Slab Systems}, journal = {Toward Practical Modelling of Reinforced Concrete Flat Slab Systems}, year = {2017}, url = {https://doi.org/10.2749/vancouver.2017.1122}, author = {Chong Yik M. Goh and Trevor Hrynyk} } @proceedings {28938, title = {The Behavior of Curved Post-tensioned Concrete Structures without Out-of-plane Reinforcement}, year = {2016}, address = {Conference: ACI fall convention}, abstract = {Research aimed toward understanding the underlying mechanics and behaviors of curved post-tensioned concrete structures subject to prestressing loads is somewhat limited in the literature. Previous research focused on radial (i.e., out-of-plane normal) stress development has been analytical and, to the research team{\textquoteright}s knowledge, there is no experimental research on this topic currently available in the public domain. As a result, this research study is aimed at producing unique experimental data to gain important insights into the effect of localized tensile stresses and concrete delamination behavior in curved post-tensioned structures. Two curved post-tensioned concrete wall assemblies were constructed and tested to delamination failure under monotonically increasing prestressing loads. In an effort to study the size-effect in delamination failure observed in such elements, all dimensions of the second specimen were double those of the first specimen, while maintaining the reinforcement ratio. The test results showed a size-effect related influence on the delamination failures. Furthermore, the compressive stresses at the onset of the first delamination crack were 0.15 fc{\textquoteright}~0.23 fc{\textquoteright} which are lower than the allowable stress limit for a service load condition in construction, 0.35 fc{\textquoteright}, specified in the ASME BPVC Section III, Division 2. Finally, the friction losses based on ACI 343R underestimated the actual friction measured during testing by 37 to 44 \%. Discussions regarding size effect, indication of delamination failure, stress concentrations around the post-tensioning ducts, and prestressing losses due to a strand bundle effect will be presented.}, url = {https://www.researchgate.net/publication/317316899_The_Behavior_of_Curved_Post-Tensioned_Concrete_Structures_without_Out-of-Plane_Reinforcement}, author = {Clint R Woods and Trevor Hrynyk and Oguzhan Bayrak} } @article {28901, title = {Modeling of steel-concrete composite elements under in-plane and out-of-plane loads}, journal = {Journal of Structural Engineering}, volume = {142}, year = {2016}, pages = {04016080}, abstract = {A nonlinear analysis procedure for steel-concrete (SC) composite structures is presented. The procedure uses smeared crack concrete constitutive modeling done on the basis of the disturbed stress field model and supplemental material models that are used to incorporate response contributions of the steel faceplates comprising SC composite elements. The procedure is implemented within the framework of a thick-shell finite-element analysis program and is verified using experimental data pertaining to SC composite structural elements subjected to exclusively in-plane or exclusively out-of-plane (i.e.,\ through-thickness) loading conditions. Lastly, the shell structure analysis program is used to numerically investigate the performance of SC composite elements subjected to combined in-plane and out-of-plane shear forces, an area directly relevant to SC infrastructure applications, yet one that is limited in the existing database of literature.}, url = {https://ascelibrary.org/doi/abs/10.1061/(ASCE)ST.1943-541X.0001554}, author = {Trevor D Hrynyk} } @article {28913, title = {TxDOT Project 0-6831 Technical Memorandum-Task 2: Manufacturer\&$\#$39;s Survey}, year = {2016}, url = {https://scholar.google.com/scholar?cluster=3777719203891255709\&hl=en\&oi=scholarr}, author = {A Katz and J Salazar and R Abyaneh and H Yousefpour and T Hrynyk and O Bayrak} } @article {28871, title = {Capturing out-of-plane shear failures in the analysis of reinforced concrete shells}, journal = {Journal of Structural Engineering}, volume = {141}, year = {2015}, pages = {04015058}, abstract = {A procedure for nonlinear analysis of RC slabs and shell structures is presented. Cracked RC is treated as an orthotropic material governed by a smeared rotating crack procedure and the constitutive formulations of the disturbed stress field model. The analysis procedure is implemented within the framework of a finite-element program employing layered thick-shell elements that consider out-of-plane (through-thickness) shear deformations. A simple modification method employing an effective shear strain concept is introduced to improve the out-of-plane performance of the layered shell element for RC applications. The adequacy of the procedure is verified using test data of RC members controlled by out-of-plane shear failure mechanisms and elements under combined in-plane and out-of-plane loading scenarios. The nonlinear finite-element program is shown to be suitable for elements exhibiting ductile or\ brittle responses, and the shear modification method introduced is found to be capable of capturing out-of-plane shear failures.}, url = {https://ascelibrary.org/doi/abs/10.1061/(ASCE)ST.1943-541X.0001311}, author = {Trevor Hrynyk and Frank J Vecchio} } @proceedings {28936, title = {Delamination Failure of Curved Post-Tensioned Concrete Structures under Monotonically Increasing Prestressing Loads}, journal = {ACI Fall 2015 Convention}, year = {2015}, url = {https://www.researchgate.net/profile/Jongkwon-Choi-2/publication/317317055_Delamination_Failure_of_Curved_Post-Tensioned_Concrete_Structures_under_Monotonically_Increasing_Prestressing_Loads/links/59b2bc95458515a5b48d2417/Delamination-Failure-of-Curved-Po}, author = {Clint R Woods and Trevor D Hrynyk and Oguzhan Bayrak} } @article {28910, title = {THE INFLUENCE OF LATERAL EXPANSIONS ON THE RESPONSE OF STEEL-CONCRETE COMPOSITE STRUCTURES}, journal = {23rd Conference on Structural Mechanics in Reactor Technology (SMiRT 23)}, year = {2015}, url = {https://scholar.google.com/scholar?cluster=5352135857163409464\&hl=en\&oi=scholarr}, author = {Trevor D Hrynyk and Frank J Vecchio} } @conference {28929, title = {Modeling of Reinforced Concrete Slabs under High-Mass Low-Velocity Impact}, booktitle = {Response of Structures uner Extreme Loading}, year = {2015}, pages = {651-658}, publisher = {DEStech Publications, Inc.}, organization = {DEStech Publications, Inc.}, abstract = {There is a growing need for analytical tools that can accurately model the behavior of reinforced concrete (RC) structures under extreme loads, particularly with respect to blast and impact. Current capabilities are almost entirely confined to hydrocodes (e.g., LS-DYNA) and such procedures have often met with limited success as they typically require complex micro-modeling representations of the structure, which is expensive in preparation and computation, and many of the commercial programs have shown deficiencies in their abilities to adequately capture cracked concrete response, particularly with regard to brittle shear-critical behavior. This paper presents the application of an alternative modeling procedure for RC slabs and shells subjected to blast and impact loads. The nonlinear finite element program employed uses a layered thick-shell element with RC constitutive modeling done in accordance with the formulations of the Disturbed Stress Field Model, a smeared rotating crack procedure shown to be capable of accurately capturing the behavior of shear-critical elements under conventional static loads. The smeared modeling approach differs from that typically employed by hydrocodes and results in simple model construction and reduced computation cost. The program is used to model the response of intermediate-scale RC and steel fiber-reinforced concrete slabs tested under repeated high-mass low-velocity impacts. Using simple finite element meshing techniques and material behavioral models requiring only basic user input, good correlation between the observed and modeled slab response was attained. The analyses provided high accuracy estimates of peak and residual displacements and successfully captured the punching shear failure modes observed experimentally.}, url = {https://www.researchgate.net/profile/Trevor-Hrynyk-2/publication/279798819_Modeling_of_Reinforced_Concrete_Slabs_under_High-Mass_Low-Velocity_Impact/links/5c7aac9f299bf1268d33314b/Modeling-of-Reinforced-Concrete-Slabs-under-High-Mass-Low-Velocity-Impact.p}, author = {Trevor D Hrynyk and Frank J. Vecchio} } @article {28710, title = {Behavior of Steel Fiber-Reinforced Concrete Slabs Under Impact Loads}, journal = {ACI Structural Journal}, volume = {111}, year = {2014}, pages = {1213-1224}, abstract = {Seven intermediate-scale slabs were constructed and tested to failure under sequential drop-weight impacts. The slabs contained longitudinal reinforcing bars and were constructed with steel fiber contents ranging from zero (that is, conventional reinforced concrete) to 1.50\% by volume. The data from the testing program were used to further assess the performance of steel fiber-reinforced concretes in impact-resistant applications and to provide a well-documented dataset pertaining to a research area which is currently limited within the literature. The test results showed that the addition of the steel fibers was effective in increasing slab capacity, reducing crack widths and spacings, and mitigating local damage under impact. Although the slabs in the program were designed to be flexure-critical under static loading conditions, the development of inertial forces under impact loading conditions led to observed responses and failure modes that were governed by shear.}, url = {http://www.vectoranalysisgroup.com/journal_publications/jp88.pdf}, author = {Trevor D Hrynyk and F Vecchio} } @article {28870, title = {Behaviour and modelling of reinforced concrete slabs and shells under static and dynamic loads}, journal = {University of Toronto}, year = {2013}, abstract = {A procedure for improved nonlinear analysis of reinforced concrete (RC) slab and shell structures is presented. The finite element program developed employs a layered thick-shell formulation which considers out-of-plane (through-thickness) shear forces, a feature which makes it notably different from most shell analysis programs. Previous versions were of limited use due to their inabilities to accurately capture out-of-plane shear failures, and because analyses were restricted to force-controlled monotonic loading conditions. The research comprising this thesis focuses on addressing these limitations, and implementing new analysis features extending the range of structures and loading conditions that can be considered. Contributions toward the redevelopment of the program include: i) a new solution algorithm for out-of-plane shear, ii) modelling of cracked RC in accordance with the Disturbed Stress Field Model, iii) the addition of fibre-reinforced concrete (FRC) modelling capabilities, and iv) the addition of cyclic and dynamic analysis capabilities. The accuracy of the program was verified using test specimens presented in the literature spanning various member types and loading conditions. The new program features are shown to enhance modelling capabilities and provide accurate assessments of shear-critical structures. An experimental program consisting of RC and FRC slab specimens under dynamic loading conditions was performed. Eight intermediate-scale slabs were constructed and tested to failure under sequential high-mass low-velocity impact. The data from the testing program were used to verify the dynamic and FRC modelling procedures developed, and to contribute to a research area which is currently limited in the database of literature: the global response of RC and FRC elements under impact. Test results showed that the FRC was effective in increasing capacity, reducing crack widths and spacings, and mitigating local damage under impact. Analyses of the slabs showed that high accuracy estimates can be obtained for RC and FRC elements under impact using basic modelling techniques and simple finite element meshes.}, url = {https://tspace.library.utoronto.ca/handle/1807/35851}, author = {Trevor Hrynyk} } @proceedings {28940, title = {Comparing slenderness effects on the out-of-plane behavior of URM infills using modern retrofits}, journal = {Fourth International Conference on FRP Composites in Civil Engineering (CICE2008)}, year = {2008}, abstract = {In this study, modern retrofit materials were implemented in an attempt to improve the out-of-plane behavior of URM walls. The laboratory testing of the retrofitted walls was divided into two phases of study: slender walls where wall behavior was controlled entirely by bending, and non-slender walls where the presence of arching action was observed. In both phases of study the retrofit systems were found to be effective in improving the behavior of the URM walls. Additionally, the study sheds light on the effect of slenderness on wall capacity, and the relationship between slenderness and retrofit effectiveness.}, url = {http://citeseerx.ist.psu.edu/viewdoc/download?doi=10.1.1.689.9655\&rep=rep1\&type=pdf}, author = {Trevor Hrynyk and J J Myers} } @article {28869, title = {Out-of-plane behavior of URM arching walls with modern blast retrofits: Experimental results and analytical model}, journal = {Journal of structural engineering}, volume = {134}, year = {2008}, pages = {1589-1597}, abstract = {A series of framed unreinforced masonry (URM) infill walls were retrofitted with modern materials to evaluate the abilities of these materials to mitigate blast effects. The walls were constructed from traditional and alternative masonry materials to assess the applicability of using a wood-fiber fly ash material for infill construction. The walls were tested in the laboratory under static conditions and were evaluated using several criteria: energy absorption, out-of-plane load resistance, out-of-plane deformability, and the reduction of masonry debris scatter upon collapse. Due to the presence of the surrounding frame structure, all of the walls in this program experienced some form of an arching mechanism. The use of a spray-on polyurea material was found to be highly effective in improving URM energy absorption and reducing masonry fragmentation. Infill walls retrofitted with a combination of fiber-reinforced polymer (FRP) grids and polyurea material were found to fail prematurely due to a lack of anchorage between the strengthened walls and surrounding structure. A simplified analytical model to estimate the ultimate out-of-plane capacity for FRP strengthened URM arching walls was developed. The analytical model was empirically calibrated using test data from this work as well as previous studies. The model predictions agree well with the experimental results reported in this paper.}, url = {https://ascelibrary.org/doi/abs/10.1061/(ASCE)0733-9445(2008)134:10(1589)}, author = {Trevor D Hrynyk and John J Myers} } @conference {28902, title = {An analytical approach to predict the out-of-plane behavior of FRP retrofitted masonry infill walls with arching action}, booktitle = {Proc., 3rd Int. Conf. Advanced Composites in Construction}, year = {2007}, pages = {320-327}, abstract = {Externally-bonded fiber reinforced polymer (FRP) laminates and grids have been proven to greatly enhance the out-of-plane flexural capacity of unreinforced masonry (URM) walls that behave as simply supported walls without arching action. URM infill wall systems subjected to out-of-plane loads may be considered to fall into one of two categories:(1) slender wall systems without arching action, and (2) non-slender walls with arching action. When the slenderness ratio (height/thickness) of the infill wall is low an arch will form between the boundary elements resulting in the ability of the wall system to carry significantly higher out-of-plane loads. It has been reported that when the slenderness ratio (h/t) is larger than 20, the effect of arching action is negligible (Angel et al., 1994). For walls having low height-to-thickness slenderness ratios and built between rigid supports, the FRP contribution decreases because the effect of arching. Due to arching, the increase of capacity in walls strengthened with FRP laminates and grids may be considerably less than expected. The behavior of FRP strengthened walls prone to arching action is often controlled by localized crushing of masonry at the supports. This paper presents an analytical approach for determining the out-ofplane capacity of masonry walls strengthened with FRP laminates considering the arching mechanism and the stiffness contribution of the wall system. The paper also discusses limitations of FRP strengthening when arching will be present. Results of on-going and past experimental programs were used to compare the proposed methodology.}, url = {https://d1wqtxts1xzle7.cloudfront.net/52037379/AN_ANALYTICAL_APPROACH_TO_PREDICT_THE_OU20170305-3845-a5p7rz.pdf?1488766767=\&response-content-disposition=inline\%3B+filename\%3DAn_analytical_approach_to_predict_the_ou.pdf\&Expires=1624981526\&Signature=HiA~-AN}, author = {Trevor Hrynyk and Nestore Galati and John J Myers} } @article {28896, title = {Comparative study on the out-of-plane behavior of retrofitted masonry wall systems with arching action}, journal = {10th North American Masonry Conference}, year = {2007}, pages = {305-316}, url = {https://scholar.google.com/scholar?cluster=6512304249608729352\&hl=en\&oi=scholarr}, author = {Trevor Hrynyk and John J Myers} } @article {28930, title = {Incorporation of Hands-on Experiments in an Introductory Structural Analysis Course.}, year = {2007}, url = {https://scholar.google.com/scholar?cluster=13274506512001240562\&hl=en\&oi=scholarr}, author = {A AYOUB and A BELARBI and Trevor Hrynyk and JJ MYERS and W SCHONBERG} } @article {30836, title = {A Simplified Design Methodology Accounting for the Arching Effects In Masonry Walls Strengthened with FRP Materials and Subject to Out-Of-Plane Loads}, journal = {A Simplified Design Methodology Accounting for the Arching Effects In Masonry Walls Strengthened with FRP Materials and Subject to Out-Of-Plane Loads}, year = {2007}, url = {http://hdl.handle.net/11588/120095} } @article {30837, title = {Static evaluation of the out-of-plane behavior of URM infill walls utilizing modern blast retrofit systems}, journal = {Static evaluation of the out-of-plane behavior of URM infill walls utilizing modern blast retrofit systems}, year = {2007}, url = {http://scholarsmine.mst.edu/masters_theses/4564} } @report {28932, title = {Incorporation of Hands-on Experiments in an Introductory Structural Analysis Course}, year = {2006}, institution = {University of Missouri-Rolla, Department of Civil, Architectural, and Environmental Engineering}, url = {https://d1wqtxts1xzle7.cloudfront.net/44079357/Incorporation_of_Hands-on_Experiments_in20160324-6045-wgv44.pdf?1458852522=\&response-content-disposition=inline\%3B+filename\%3DIncorporation_of_Hands_on_Experiments_in.pdf\&Expires=1625089583\&Signature=NYmTVYxQ}, author = {John J Myers and Trevor Hrynyk and Ashraf Salah Eldin Ayoub and Abdeldjelil Belarbi and William P Schonberg} } @report {28934, title = {Incorporation of Hands-on Experiments in an Introductory Structural Analysis Course}, year = {2006}, institution = {University of Missouri-Rolla, Department of Civil, Architectural, and Environmental Engineering}, url = {https://d1wqtxts1xzle7.cloudfront.net/44079357/Incorporation_of_Hands-on_Experiments_in20160324-6045-wgv44.pdf?1458852522=\&response-content-disposition=inline\%3B+filename\%3DIncorporation_of_Hands_on_Experiments_in.pdf\&Expires=1625089860\&Signature=BUIBImX3}, author = {John Joseph Myers and Trevor Hrynyk and Ashraf Salah Eldin Ayoub and Abdeldjelil Belarbi and William P Schonberg} } @article {30838, title = {Out of Plane Behavior of Masonry Infill Walls Retrofitted with a Reinforced Polymer Grid and Polyurea System}, journal = {Out of Plane Behavior of Masonry Infill Walls Retrofitted with a Reinforced Polymer Grid and Polyurea System}, year = {2006}, url = {http://scholarsmine.mst.edu/civarc_enveng_facwork/197} } @article {30840, title = {A SIMPLIFIED DESIGN METHODOLOGY ACCOUNTING FOR THE ARCHING EFFECTS IN MASONRY WALLS STRENGTHENED WITH FRP MATERIALS AND SUBJECT TO OUT-OF-PLANE LOADS}, journal = {A SIMPLIFIED DESIGN METHODOLOGY ACCOUNTING FOR THE ARCHING EFFECTS IN MASONRY WALLS STRENGTHENED WITH FRP MATERIALS AND SUBJECT TO OUT-OF-PLANE LOADS}, year = {2006}, url = {http://citeseerx.ist.psu.edu/viewdoc/summary?doi=10.1.1.691.1904} } @proceedings {28935, title = {Strengthening of one way reinforced concrete slabs with mechanically-anchored unbonded FRP strips}, journal = {Proceedings Annual Conference - Canadian Society for Civil Engineering}, volume = {2005}, year = {2005}, author = {Tamer. El-Maaddawy and Jamie Hamelin and Trevor Hrynyk and Lori Schaus and Khaled Soudki} }