This study evaluated the effectiveness of carbon fiber-reinforced polymer (CFRP) composites in strengthening RC beams for a simple span overhanging from both ends and subjected to equal concentrated forces at each end. This innovative loading configuration allows for investigating the performance of CFRP composites under pure moment within the middle span and ensuring continuity of the moment over the supports, which cannot be captured using the classical simple span with four-point loading configuration. A nonlinear finite-element analysis (NLFEA) using Abaqus software was carried out to accomplish the objectives of this study. The NLFEA models were verified initially based on independent experimental results from the literature to calibrate the NLFEA models in terms of the material constitutive models, boundary conditions, and meshing. Then 12 NLFEA models were created with different strengthening schemes of CFRP strips, varying in terms of length and number of layers, in addition to a control beam. All the evaluated RC beams were similar in terms of length and cross-sectional dimensions, material properties, and steel reinforcement. The results revealed that the developed NLFEA models can reasonably simulate the flexural behavior and failure mode of the studied RC beams, which are significantly affected by the configuration and length of the CFRP strips. The results also indicated that it is essential to extend the CFRP strips from the middle span toward the overhanging span to provide continuity and allow the CFRP strips to contribute effectively to the flexural strength.
In response to the global shift toward renewable energy, wind energy is a pivotal player in sustainability. Floating offshore wind turbines (FOWTs) emerge as a promising solution for expanding wind energy into economically challenging deep waters. Despite their potential, challenges persist, necessitating a thorough understanding of the complex coupling effects between wind turbine aerodynamics and hydrodynamics, particularly during the design phase. This study highlights this critical need and extends its scope to review the relevant existing literature. The paper provides insights into the design considerations and assessment methodologies crucial for both new structures and the evaluation of existing ones. Through modeling in the Ashes wind turbine software, the study reveals that platform surge motion significantly impacts rotor performance, causing rotor power and thrust fluctuations. By comparing various wind and sea states with baseline testing, the study underscores the necessity of coupling aerodynamic and hydrodynamic forces for accurate performance predictions. Besides, the paper offers actionable recommendations for designing and optimizing FOWTs, and sheds light on the challenges and opportunities within offshore wind energy, offering valuable guidance for engineers working toward sustainable energy solutions.
Reinforced concrete (RC) construction stands as one of the most prevalent engineering endeavors, underscoring the importance of routine structural health assessments. Numerous factors, including overloading, design deficiencies, and fatigue, pose risks to RC structures by inducing cracks in various components. These damages significantly compromise the strength of RC constructions, necessitating vigilant monitoring to avert catastrophic structural failures. Structural health monitoring (SHM) techniques primarily aim to detect such damages. Leveraging piezoelectric (PZT) principles, the electromechanical impedance (EMI) methodology emerges as a promising SHM approach. EMI relies on variations in responses recorded through the electromechanical interaction between PZT and the structure to identify structural damages. Admittance signatures, comprising conductance (G) and susceptance (B), serve as indicators of structural condition, with deviations in the plot of G across a frequency range signaling structural deterioration. PZT transducers, either embedded within the structure or surface bonded, facilitate damage monitoring. This study aims to assess the damage detection capabilities of surface bonded PZT and embedded concrete vibrational sensors (CVS) in grade M25 RC beams. The root mean square deviation (RMSD) serves as the damage index, derived from variations in signatures recorded at different load levels. Experimental testing, conducted on nine RC beam specimens using a universal testing machine (UTM), yielded reliable results for comparison. Comparative analysis between surface bonded PZT and embedded CVS evaluated their performance in detecting structural anomalies under various load levels using RMSD values. Baseline conductance signatures revealed a lower amplitude for CVS due to inherent damping effects within the concrete material. Additionally, CVS consistently displayed lower RMSD values than PZT across different load levels, indicating lesser sensitivity to surface cracks and defects owing to its embedded position within the concrete.
Iran is located in a seismically active region, which poses a significant threat of destructive earthquakes. Given the dense populations they support and their structural importance, schools demand resilience across various dimensions. In this study, we aimed to evaluate the seismic performance of schools in Khorramabad, Lorestan, Iran, by obtaining resilience curves. The research involved a thorough analysis of retrofitting options for a specific school, identified through a review of data from Lorestan province. Three retrofitting options were considered: (1) bracing, (2) friction dampers, and (3) utilization of fiber-reinforced polymers (FRP) in the columns. The structure was modeled and designed using suitable software before and after implementing the retrofitting options. Incremental dynamic analysis (IDA) was conducted using recommended ground motions (including 10 ground motions for near and far fields). Subsequently, a risk analysis of the study area was performed, and a comparison was made between damage and fragility curves under different conditions; this included an assessment of potential damage in future earthquakes. The results demonstrated the efficacy of the analysis method in evaluating the seismic performance of buildings. Last, the study highlighted the building's response under different earthquake intensities and confirmed that the maximum capacity determined closely corresponded to findings from other nonlinear analyses. This approach was proven to be highly effective in assessing a building's behavior and ultimate capacity in the face of earthquakes.
Double-skin tubular columns (DSTCs) are promising modern columns with concrete sandwiched between fiber-reinforced polymer (FRP) and steel skins. Typical concentrated and localized failure modes in DSTCs can be constrained or delayed when stiffened inner steel tubes are used. DSTCs with circular cross sections are better investigated in the literature than scarcely studied square shapes, especially with variations of stiffened inner steel tubes. This study examined the nonlinear confined concrete behavior in stiffened DSTCs with square-shaped glass FRP as outer skins and stiffened steel tube as inner skins. The documented test results on 26 DSTCs were used to formulate a new analysis-oriented, axial stress-strain model for confined concrete. Primary model-formulation parameters were evaluated using a genetic algorithm (GA)-driven error minimization. A detailed parametric study was then performed on square DSTCs by incorporating the proposed stress-strain constitutive relationship for confined concrete in nonlinear finite-element analysis. The variations used in the parametric study included the shape of the inner steel tube (circular versus square), unconfined concrete strength, and flat-stiffener geometry characteristics (i.e., quantity, configuration in terms of thickness versus the number of stiffeners for similar total cross-sectional area, and its cross-sectional dimensions). Analytical results were finally used to propose a new load-bearing equation for estimating the axial load capacity of square DSTCs having stiffened inner steel skins of circular or square shapes. The proposed formulation showed better accuracy (about 2% on average and 14% maximum disparity with refined ultimate axial load capacities of DSTCs used in this study) than the existing prediction models.
The bridge inspection process has multiple steps. One obvious element is for inspectors to identify defects in the main components of the structural system and assign condition ratings. These condition ratings are somewhat subjective because they are influenced by the experience of the inspector. In the current work, processes were developed for making inferences on the reliability of prestressed concrete (PC) girders with defects at the girder component level. The Bayesian network (BN) tools constructed in this study use simple structural mechanics to model the capacity of girders. Expert opinion is used to link defects that can be observed during inspections to underlying deterioration mechanisms. By linking these deterioration mechanisms with changes in mechanical properties, inferences on the reliability of a bridge can be made based on visual observation of defects. The BN can then be used to directly determine the rating factor (RF) of individual structural elements. Examples are provided using BNs to evaluate an existing older PC bridge currently behaving as two simply supported spans. The bridge is modeled using two scenarios with the spans acting as simply supported, and then also with the link block (continuity joint) repaired so that the spans are continuous for live load. The spans are considered simply supported for all dead load.
This study addresses the challenge of detecting operational and environmental changes, termed linear damages, in building structures over their lifespan. Identification of these damages is crucial for enhancing serviceability and averting sudden disasters. However, the intricate nature of uncovering concealed changes results in demanding and time-intensive computations, posing a significant computational predicament for related algorithms. Moreover, structures are often exposed to diverse environmental noise, necessitating the development of a robust algorithm capable of effectively identifying subtly hidden damages amid varying noisy conditions with high accuracy and low time consumption. This research introduces a robust and expedited signal-based algorithm, comprising three key components: processing, feature selection, and classification. Multiresolution analysis through discrete wavelet transform is employed for processing, generating diverse features alongside several statistical indices. The grey wolf optimization algorithm is utilized for feature selection, yielding optimal features. This method not only ensures commendable performance under noisy circumstances compared with optimization algorithms such as particle swan optimization and genetic algorithms, as well as common feature extraction methods such as principal component analysis, it also accelerates computation speed by over four times compared with alternative feature-selection techniques such as ReliefF. Lastly, a supervised classification algorithm is integrated to discern distinct predefined scenarios. The efficacy of the proposed algorithm was validated using a comprehensive case study encompassing nine representative scenarios of operational and environmental damages. Incorporating four levels of noise to emulate real-world variations, the algorithm achieved compelling average accuracies of approximately 96%, 93%, 95%, 91.5%, and 89% at original data and signal-to-noise ratios (SNRs) of 10, 5, 1, and 0.5 dB, respectively.
Buildings on hill slopes have suffered significant damage from past earthquakes due to poor design and construction practices. Therefore, Indian building code restricts the natural period of building on slopes based on their shortest height. Different building configurations located on hill slopes perform differently in the event of an earthquake, making it necessary to check the applicability of provisions using elastic and inelastic analyses. This study investigated a spectrum of two-dimensional (2D) RC moment frame building configurations (with or without including infill walls as an equivalent strut), including (1) type of building configuration; (2) angle of slope; (3) boundary conditions; and (4) varying height of buildings using modal analysis, equivalent static analysis, and response spectrum analysis. Mass participation (from 80% to 37%) and base shear decrease due to extreme short columns, which demand massive forces; interstory drift decreases for buildings on hill slopes, but increases drastically by varying the boundary conditions. The responses from nonlinear static and dynamic time-history analyses were studied based on the capacity curve, performance point, and level of damage toto structural elements under the maximum considered earthquake (MCE). The presence of struts increases lateral stiffness and lateral strength for building on slopes, resulting in less damage to structural elements than regular buildings (BC1). However, damage to beams and columns is more common in bare-frame buildings than in buildings with struts, because the struts sustain more damage. Although a few building configurations on slopes incurred less damage (e.g., step-back setback buildings, due to decreased stiffness along the height), more damage is evident in the struts of other buildings on slopes. Thus, strut failure may cause a building to behave like a bare-frame building under MCE demand, sustaining more damage; this also was demonstrated with a three-dimensional (3D) building on slope. Thus, designing buildings based on code-based natural periods by assuming the sloped region to be rigid may not be valid for all building configurations. It is necessary to account for other critical parameters while placing restrictions on the building code provisions.
Previous research on seismic response analysis of dams primarily treated earthquakes as deterministic events; only a few studies on arch dams have explored earthquakes as random processes. This study introduces a three-dimensional seismic analysis of the Morrow Point arch dam, considering fully correlated random ground motion. The random ground excitation is characterized by the power spectral density function (PSDF) of the Kern County earthquake, for which the response time history is available. The spectral analysis technique describes the PSDF of the dam's response using the desired transfer function derived from Abaqus software. The analysis method is similar to that employed in finding the PSDF of the response of offshore structures from a given wave spectrum (PSDF). The method is validated by confirming the results of the proposed method with those of modal spectral analysis for empty dams and those of the time history analysis of the full reservoir dam. The results from the numerical study show that (1) the PSDF of responses obtained by modal spectral analysis using the first ten modes of the dam matches with those obtained by the direct analysis using transfer functions for the empty dam; and (2) mean peak arch stresses increases along the height of the dam from base to top, whereas mean peak cantilever stresses decreases; further, the mean peak arch stresses are less than the mean peak cantilever stresses at the base.
The building fa & ccedil;ade is a vital component of a building's structure and can play a significant role in safety, structure stability, energy efficiency, and aesthetics. Fa & ccedil;ade issues and failures are increasingly occurring in various buildings and cities. Some of these issues have caused safety incidents with fatalities to the occupants and nonoccupants. Nonoccupant incidents occur in fa & ccedil;ades located close to the public right away. This has led multiple agencies to implement inspection programs and regulations that the property owners shall comply with to avoid safety incidents. Despite these regulations, fa & ccedil;ade failures and safety incidents remain an issue, with various root causes, which could be due to insufficient original design documents, construction procedures, loading, or structural aging. This case study will discuss possible fa & ccedil;ade defect types and locations caused by soil, foundations, temperature changes, wind, and seismic. It will also discuss how to identify defects in various areas of the structure, including bearing and nonbearing exterior walls. In addition to these findings, those should be reported in detail with priorities to ensure effective urgent procedures are in place to avoid incidents. An example of a New York fa & ccedil;ade inspection program is discussed, and the reporting procedure is discussed with a fatal case study. In 2015, falling pieces of terra cotta caused the death of a two-year-old child; this incident led city officials to adopt changes in inspection requirements and procedures. In conclusion, gaining knowledge about the causes of defects, their location, and proper inspection and reporting procedures are crucial to public safety. This benefits not only the property owner but also the public, all trades involved in new project construction, inspectors, and officials to help avoid safety incidents.
In recent decades, various strategies have been employed to enhance the seismic resilience of structural systems in the event of earthquakes. One such innovative method is the elliptic-braced moment-resisting frame with a rotational friction damper (ELBRF-RFD), which serves as a displacement-restraint bracing technique connecting the elliptic brace to the upper beam. To design an ELBRF-RFD based on contemporary guidelines, for the first time, this study introduces the quantification of seismic performance factors (SPFs) through incremental dynamic analysis (IDA). The research then proceeded to design 3-story, 5-story, and 7-story archetypes in type II soil using the presumed SPFs. A comparative analysis was conducted with inverted-V braced frames equipped with rotational friction dampers (CBF-RFDs). The performance of each archetype was evaluated through nonlinear static pushover analysis (NSPA) and IDA, employing 15 earthquake records from the past and using the OpenSees software. For the response modification factor, suggested values of 11.2 (allowable stress method) and 7.8 (ultimate limit state methods) were identified. Furthermore, the collapse probability of archetypes was determined by employing fragility curves and considering sources of uncertainty.
Steel plate girders are susceptible to web buckling due to slender web. This phenomenon creates an undesirable failure mode and limits their ultimate load capacity. The use of fiber-reinforced polymer (FRP) composite materials offers a good prospect of strengthening the slender web of plate girders to avoid web buckling. This paper presents the details of experimental testing of steel plate girders with nonrigid end posts. These girders were tested in three-point bending. The end shear panels of the girders were strengthened by glass FRP (GFRP) pultruded section stiffeners or glass fiber fabric composite. GFRP stiffeners were applied either vertically or along the compression diagonal in the shear panel. All strengthened panels failed by web shear buckling associated with a breakdown of the employed strengthening scheme. It was found that the shear capacity of the panel remained unchanged by replacing the steel stiffener with GFRP stiffeners in the end panel. The critical buckling load of the strengthened panels increased up to 44% compared to the unstrengthened panel. The shear capacities of the panels strengthened by the glass fabric composite and diagonal GFRP pultruded section were the highest and similar to each other. Both these panels resisted a 50% larger shear compared to the unstrengthened panel. The positions of the plastic hinges in all tested panels were the same due to the same ratio of panel length and depth of the web.
This paper reports a comprehensive study on the performance of the in-plane behavior of masonry walls. The use of wire rope and neoprene as a method for reinforcing existing masonry walls is proposed in this paper. The performances of the five walls with and without reinforcement were evaluated using experimental tests and numerical models. The first specimen was an unreinforced masonry wall (witness wall), which was tested under simultaneous cyclic and vertical loading. This wall was modeled using a simplified micro-modeling approach in the standard finite element software, Abaqus. A finite element (FE) study verified the experimental results to predict the in-plane behavior of masonry walls. Furthermore, to investigate the in-plane behavior of nonload-bearing walls in masonry structures, another sample with dimensions and a lateral loading protocol similar to the first sample was modeled by removing the vertical load. After a comprehensive understanding of the failure modes and damage mechanisms, the unreinforced load-bearing wall was strengthened using steel cables and neoprene in a cross-diagonal reinforcement pattern, whereas the unreinforced nonload-bearing wall was strengthened using steel cables and neoprene in a vertical pattern. The details of the modeling and wall construction, test setup, testing procedure, and results are described in detail in this study. The results indicated that the energy absorption capacity of the unreinforced walls was extremely low, and the effects of narrowing and asymmetry in the hysteresis curve were observed. The proposed retrofitting system increased the lateral load capacity, initial stiffness, deformation capacity (reducing the residual deformation), and energy dissipation capacity and created a self-centering response in the wall.
Ultrahigh-performance concrete (UHPC) is a type of concrete that has gained attention from researchers for its potential use in various structural applications to improve the behavior of concrete structures. Despite this interest, there are limited experimental test results available on how the ratio of stirrups and the dosage of steel fibers affect the torsional behavior of UHPC beams. This study presents an experimental investigation and theoretical prediction of torque capacity (UHPC) of beams with different ratios of stirrups and dosages of steel fibers under pure torsion. One normal-strength concrete (NSC) beam and 10 UHPC beams with 150x200-mm cross sections were tested. The experimental parameters were the dosages of steel fibers (1% and 2%) and the spacings of the stirrups of 0.0, 50,100, 150, and 200 mm. Including the UHPC high tensile strength and volume fraction of steel fibers, an expression for cracking and ultimate torques of UHPC was proposed and verified. Results showed that the UHPC beams have brittle failure modes compared to NSC beams. Results demonstrated that the UHPC beams showed higher initial cracking and ultimate torsional moments than the NSC beam. The additional steel fibers enhance the torsional properties, and this improvement was linearly at the effective stirrup's ratio higher than 0.25%. The 1% or higher steel fiber dosage was confirmed to be enough to substitute the missing strength of the stirrups. Results of previous research and the suggested cracking and ultimate torque equations of UHPC agreed with the experimental results.
This paper presents a model to determine the theoretical braking loads for railway tracks. Two braking load studies are reviewed: one by the Office of Research and Experiment Committees and one related to the European specifications for braking load. The maximum braking load of a rail is determined by multiplying wheel load with an appropriate coefficient of adhesion. The maximum braking load is not an input in the current track-structure interaction model. Currently, braking load per meter of track, e.g., 30 kN/m of track, is an input in a track-structure interaction model. Thus, a formula is suggested to convert the maximum braking load into an equivalent braking load per meter of track (kN/m of track). The formula is applied to compute the braking loads that are validated against the observations from Office of Research and Experiment studies and Eurocode values. It is crucial to choose a proper value of coefficient of adhesion to compute the braking load; therefore the coefficient of adhesion is reviewed. A formula is also suggested to determine the extent of the track affected by the braking load. The formulas are applied to both ballasted and direct-fixation track; they demonstrate how the value for braking load per meter of track and the value for affected track length due to braking change with the track form and quality of track maintenance. The extent of the affected track due to braking may be the length of track on the bridge approaches to be included in a track-structure interaction model. The model for determining the theoretical braking loads for railway tracks would be helpful for attaining a better understanding of the braking action of rolling stock.
This paper presents the results of experimental testing of block masonry prisms and wallettes under uniaxial compression. The compressive load was applied in a direction perpendicular or parallel to the bed joints. Masonry prisms and wallettes were tested in the former direction, whereas only wallettes were tested in the latter direction. No influence of mortar strength or block thickness was observed on the cracking and failure patterns of specimens of similar type, although material crushing and spalling was marginally influenced by block strength. The cracking load for the assemblages tested normal to the bed joint was nearly 90% of the peak load capacity and higher as compared to 70% of the peak load capacity for the wallettes tested parallel to the bed joints. Similar load capacity and elastic modulus were observed for the prisms and wallettes tested normal to the bed joints. Whereas the strength for the wallettes tested parallel to the bed joints was 49%-83% less compared to those tested normal to the bed joints, their elastic modulus was nearly 25% higher. The experimental strength and strain values were compared with the existing analytical methods, which correlated well.
Although the natural gas pipeline network is the most efficient and secure transportation mode for natural gas, it remains susceptible to external and internal risk factors. It is vital to address the associated risk factors such as corrosion, third-party interference, natural disasters, and equipment faults, which may lead to pipeline leakage or failure. The conventional quantitative risk assessment techniques require massive historical failure data that are sometimes unavailable or vague. Experts or researchers in the same field can always provide insights into the latest failure assessment picture. In this paper, fuzzy set theory is employed by obtaining expert elicitation through linguistic variables to obtain the failure probability of the top event (pipeline failure). By applying a combination of T- and S-Norms, the fuzzy aggregation approach can enable the most conservative risk failure assessment. The findings from this study showed that internal factors, including material faults and operational errors, significantly impact the pipeline failure integrity. Future directions should include sensitivity analyses to address the uncertainty in data to ensure the reliability of assessment results. Natural gas pipelines are efficient and reliable transportation modes. The integrity of these valuable assets is threatened by various risks such as corrosion, environmental factors, human errors, and mechanical faults. For newly developed or less monitored pipeline networks, historical data are either unavailable or faulty. To overcome this shortcoming, experts from pipeline networks can provide invaluable insight by providing their expert opinion. This study uses the expert's elicitation by applying a fuzzy aggregation approach to predict the pipeline failure probability. The finding of this study confirmed that material faults and operational errors are the most critical risk factors leading to pipeline failure. The results of this study can be used to develop effective mitigation strategies for pipeline networks to minimize future failures.
Earthquakes are one of the most common natural disasters resulting in loss of life and property. A method for reducing damage and fatalities is to evaluate the fragility, i.e., determining the degree of an earthquake susceptibility of a structure using structural analysis. Bridges are categorized as lifeline constructions, as they must be operational in the case of an earthquake. The closure of damaged bridges due to unsatisfactory working conditions might have an adverse impact on everyday traffic. The proposed research would look into the seismic danger that bridges represent located in Surat city of Gujarat. In this work, nonlinear static analysis has been used for investigation. The fragility function has been used to evaluate damage to bridges of varied spans, material quality based on Indian seismic provisions. This investigation can keep track of the possibility of specific damaging circumstances. Using the HAZUS approach, a probability damage assessment has been done. Using ArcGIS software, the likelihood, size, and severity of bridges in Surat have been evaluated. The distinction of present study lies in extending beyond the confines of the HAZUS technical manual, which primarily focuses on generating damage state probabilities for bridges. In this study, author moves a step further by applying this technique to a specific set of bridges, allowing to observe variations in damage state parameters across different bridge types. This approach enables easy comparisons between various bridges, aiding in the identification of specific risk factors and informing subsequent measures for risk mitigation.
The accurate prediction of residual compressive strength (RCS) of concrete plays a critical role in assessing concrete constructions' safety and structural integrity following exposure to elevated temperatures. Existing ensemble models exhibit RCS prediction capabilities, yet they are constrained by their opaque nature. This research endeavors to develop an intelligible model for RCS by employing five ensemble machine-learning models, namely, random forest (RF), adaptive boosting (AdaBoost), gradient boosting (GBoost), light gradient boosting (LGBoost), and extreme gradient boosting (XGBoost), and integrating Shapley additive explanations (SHAP) to ascertain the precise importance of each input variable in forecasting the RCS of concrete under elevated temperature conditions. The input variables encompass concrete type, compressive strength, aggregate type, water-cement ratio, heating type, heating rate, maximum core temperature, and cooling type. Model performance is appraised using established performance metrics such as mean absolute error (MAE), mean squared error (MSE), root-mean squared error (RMSE), and coefficient of determination (R2). The analytical results exhibit the efficacy of employing machine-learning models in accurately predicting the RCS of concrete under elevated temperature conditions. Among the implemented models, XGBoost demonstrated the highest performance, yielding an R2 value of 0.876, closely trailed by the LGBoost model at 0.871. The SHAP analysis elucidates the crucial role of core temperature, water-cement ratio, heating rate, and compressive strength in determining the RCS of concrete.
Concrete-filled fiber tubes (CFFT) are gaining prominence as a feasible alternative to traditional materials for a variety of structural applications. However, research on structural performance of CFFT beams is still scarce. This paper presents a finite-element (FE) analysis of CFFT beams validated by experimental results from literature. Then, a parametric study investigating structural performance of post-tensioned (PT CFFT) beams was conducted using 34 FE models using ANSYS nonlinear FE software program. The parametric study results showed that both normal-strength concrete (NSC) and high-strength concrete (HSC) filled PT CFFT exhibit identical nonlinear responses. Increasing the prestressed and non-prestressed reinforcement ratio significantly improved the overall performance of PT CFFT beams. Placing the PT tendons at the bottom of PT CFFT beams enhanced the cracking, yielding, and ultimate load-carrying capacities by 7.98%, 12.32%, and 9.03% for NSC-filled PT CFFT beams, respectively. Doubling the axial stiffness of the tube laminate structure increased the ultimate load, energy absorption capacity (EAC), pre-yielding stiffness (Kpre), and post-yielding stiffness (Kpos) by 18.5%, 12.15%, 9.21%, and 8.2%, respectively for NSC-filled PT CFFT beams. Beams with straight PT tendons exhibited increased cracking, yielding, and ultimate load capacity by 10.85%, 14.60%, and 13.58% more than those with curved-profile tendons. The ductility of PT CFFT beams is more sensitive to the amount of prestressed reinforcement ratio and concrete strength has a minimal effect on the structural performance of PT CFFT beams.
