Plastic Rotation Research Articles

Numerical investigation on plastic hinge behavior of hybrid steel-FRP reinforced concrete columns

This paper presents a numerical study on the plastic hinge behavior and rotation capacity of concrete columns reinforced with a combination of steel bars and fiber-reinforced polymer (FRP) bars. A meso-scale numerical model, which considers the internal heterogeneity of concrete and bond behavior between concrete and longitudinal reinforcements, was developed and validated. The failure modes, lateral load-displacement responses, and the physical plastic hinge lengths of hybrid steel-FRP reinforced concrete (SFRC) columns were investigated and compared with those of conventional steel-reinforced concrete columns. The results indicated that the steel yielding zone and curvature localization zone of SFRC columns with FRP longitudinal bars were enlarged, due to the relatively low modulus of FRP bars. After that, a parametric analysis was performed to study the plastic hinge length of SFRC columns with respect to the nominal area ratio of FRP longitudinal bars, shear span-to-depth ratio, axial load ratio, and longitudinal reinforcement ratio. A new empirical model was proposed to predict the equivalent plastic hinge length, which was subsequently integrated into an analytical method for predicting the ultimate rotation. The comparison of predictions with simulation and test results demonstrated the accuracy of both the proposed empirical model and analytical method.

Prediction on seismic performance levels of reinforced concrete beams by considering crack development

The plastic rotation angle or deflection is typically used as the indicator to evaluate the earthquake-induced damage and classify the seismic performance levels of reinforced concrete (RC) beams. Herein, one of the most important issues is to determine the seismic performance level limits of RC beams. Whereas, different countries provided their specific method to determine the limit values by considering the loading-carrying capacity of RC beams, which could not be used to describe the earthquake-induced seepage of structures, especially for underground structures. Therefore, in this study, the seismic performance level limits of RC beams were predicted by using the machine learning methods and considering the development of cracks. Firstly, the seismic performance level limits of RC beams were presented after discussing the methods in different codes and the development of cracks. Then an earthquake performance test database of RC beams was established after collecting 452 test results of RC beams, and Pearson correlation analysis was conducted for feature selection to determine the input mechanical parameters and dimensional parameters for machine learning. Meanwhile, the correlation between the inputs and limit values was analyzed using the mutual information method. Regression models of seven machine learning methods were then established to predict the performance level limits of RC beams, and the hyperparameters of the machine learning models were optimized with the TPE optimization algorithm and cross-validation. The generalization ability of the prediction models was evaluated and the accuracy of predicted results by different methods was analyzed. Finally, the predicted seismic performance level limits of RC beams could be used to evaluate the earthquake-induced damage of RC beams by combining them with the seismic behavior of RC beams.

The Educational Benefits of Plastic Surgery Rotations for Off-Service Residents.

With increasing specialization among surgical divisions, a well-rounded education during a surgical residency is often accomplished by rotating among different subspecialties. Inclusion of specific rotations in the resident curriculum can be considered as a cost-benefit calculation balancing the value of exposure to a subspecialty versus the opportunity cost of potential learning from another rotation. We find that often these decisions are based on anecdotal feedback. Our goal is to supplement these reports with a quantifiable metric of learning achieved on the plastic surgery rotation. Our hypothesis in this prospective study was that residents would demonstrate improved performance on a post-rotation test after their 1-month rotation on plastic surgery compared to the pre-rotation test. A question bank was developed to reflect institutional curriculum objectives and clinical scenarios commonly seen on the service. The questions were developed, validated and vetted in collaboration with medical educators and attending plastic surgeons yielding 20 questions available for use. Postgraduate year 1 residents were given a 10-question test before and after their plastic surgery rotation. A one-tailed paired t-test was used to assess improvement between the pre-rotation test and the post-rotation test. A total of 378 tests were administered with 228 (60%) pre- and post-rotation tests completed meeting inclusion criteria. Average percentage of correct answers for the pre-rotation test was 29% and 88% for the post-rotation test showing a differential improvement of 58% (p < 0.001). Surgical trainee time is a limited commodity. Each clinical rotation needs proven consistent benefit for the trainees. We developed a questionnaire that documents the improvement in clinical knowledge after a one-month rotation on plastic surgery relative to before. The test results were consistent even when comparing trainees who did the rotation early versus late in the PGY-1 year. Clinical exposure reinforces and solidifies specialty learning.

Experimental and numerical study on flexural performance of ultra-high performance concrete frame beams reinforced with steel-FRP composite bars

This paper presents the bending tests of four ultra-high performance concrete (UHPC) frame beams and one normal strength concrete (NSC) frame beam, all reinforced with steel-FRP composite bars (SFCBs). A comprehensive analysis was carried out, encompassing evaluation of the failure mode, crack propagation, bearing capacity, deformation, strain response, and plastic rotational capacity of the frame beams. Investigating the effects of concrete type, reinforcement type, and beam-end reinforcement ratio on the flexural performance of the frame beams was a key aspect of this study. A three-dimensional finite element (FE) model of the frame beam was established and rigorously verified. The developed model enabled a detailed parametric analysis involving the steel ratio, the yield strength of the inner core steel bar, the elastic modulus of the FRP, and the ultimate tensile strength of the SFCB. The results indicated a consistent failure mode of all frame beams: crushing of concrete at the beam-end, initiating a sequence of plastic hinge occurrence starting at the beam-end and then progressing to mid-span. The substitution of normal strength concrete with UHPC significantly enhanced various aspects of the frame beams, including the flexural capacity, deformation, ductility, ultimate energy dissipation, and plastic rotational capacity, while inhibiting the generation and expansion of cracks. Notably, the plastic rotation angle of SFCB-UHPC frame beams was 4.9 times greater than those of steel-UHPC frame beams, emphasizing the effectiveness of SFCB in enhancing the beam-end plastic rotational capacity. A decrease in the beam-end reinforcement ratio significantly reduced the flexural capacity, ultimate energy dissipation, and beam-end plastic rotational capacity, while improving ductility. Additionally, the study established a formula for calculating the equivalent plastic hinge length, utilizing the relative compressive zone height and effective section height of the beam-end controlling section as variables, which demonstrated good alignment between predicted and experimental results.

Vertical diaphragms for moment connection of thin-walled CFT column to steel beam

A vertical diaphragm scheme is proposed to connect the concrete-filled thin-walled steel tube (thin-walled CFT) column and steel beam, as an alternative to horizontal diaphragm connections: dual vertical diaphragms are installed inside the steel tube, considering poor out-of-plane resistance of the thin tube wall. For verification of the moment connection, two experimental programs were carried out. In the first experiment, an ultimate tension test was conducted for flange-to-column connections, to identify the fundamental behavior of the proposed connection (i.e., strength, failure mode, and out-of-plane deformation). The design parameters, such as the thickness, number, and continuity of the vertical diaphragms, were considered. All the test specimens exceeded the design strengths based on a yield line model (i.e., the tensile capacity-to-demand ratios ranged Tu/TYL = 1.11–1.31), without early fracture of welded joints. In particular, at the design strengths, the tube out-of-plane deformations were more limited with the heavier diaphragms. In the second experiment, beam-to-column connections using prototype I-section steel were tested under cyclic flexure, to verify the joint flexural strength and rigidity as well as the seismic performance. The beam-to-column connections failed by the beam flexural mechanism, whereas damage was marginal at the joint wall (i.e., the flexural capacity-to-demand ratios ranged Mu/Mj = 0.87–1.09). Overall, the dual diaphragms were effective in achieving rigid (full-strength) connections with satisfactory plastic rotation of the beam. On the basis of the test results, design considerations were recommended for the vertical diaphragm connections.

Cyclic loading test on hysteresis performance of replaceable link with slit web

The paper introduces a novel design for replaceable links, which incorporates strategically placed slits in the web to reduce the bearing capacity of the link. This design innovation ensures localized plastic deformation within the link, facilitating disassembly and replacement after earthquake. Two types of steel materials, Q235 steel, and LYP160 steel, are employed in constructing the replaceable links. Three replaceable links with slit web were designed according to the material properties of the steel and the number of slits and were subjected to cyclic loading tests. The test results show that the primary failure modes of the link include web failure between slits, torsional deformation of the web between slits, slight buckling of flanges and stiffeners, and web tearing. The material overstrength coefficients of the three specimens range from 0.83 – 1.41, and the overstrength coefficients due to strain hardening range from 1.08 – 2.49, with a maximum plastic rotation reaching up to 0.16 rad.

Seasonal Fluctuations in Plant-Parasitic Nematode Vertical Distributions and Their Interactions with Edaphic Factors in Vegetable Fields of South Georgia, U.S.A.

Plant-parasitic nematodes (PPNs) can be found deep in the soil profile, compounding nematode management decisions and detection. This study aimed to understand how seasonal fluctuations in edaphic factors are associated with the vertical distribution of PPNs in south Georgia's vegetable cropping systems. Five-core composite soil samples were taken monthly (March 2020 to February 2022) at three random locations in six vegetable fields. Fields represented three cropping systems (vegetable plasticulture, bare ground cucumber, and plastic bed watermelon rotation) and two regions (north and south) sampled from five 15-cm strata (0 to 15, 15 to 30, 30 to 45, 45 to 60, and 60 to 75 cm). Only soil temperatures and precipitation had seasonal fluctuations; the other edaphic factors were vertically stratified. Latitude and stratum had the strongest associations with nematode composition, showing a clear separation between the north and south regions. Variations in soil texture, porosity, moisture, and PPN vertical distribution suggested that the illuvial zone in the north region was the main factor in the differences observed between regions and strata. Seasonal fluctuations in vertical distribution were found among Meloidogyne incognita and Nanidorus spp. Higher abundances of deep-dwelling PPNs were limited to the south region in the winter for deep-dwelling M. incognita and summer and winter for Nanidorus spp., probably due to the illuvial zone barrier in the north region. Because most root-knot nematodes dwell at ≤30 cm during the summer, fumigant/nematicide applications are recommended during this season to minimize the risk of deep-dwelling escapees.

Numerical study of low‐rise composite steel frame responses to blast loading using direct simulation method

AbstractThis paper investigated the blast behavior of a low‐rise composite steel structure of three stories subjected to internal and external explosions for the same explosive charge of 250 kg TNT. A comparison of three various blast scenarios is aimed at better understanding how blast waves propagate in confined risk zones and their damage effects on far and exposed elements to an explosive charge. Evaluation of the damage level and the overall response of the proposed numerical model is done by estimating the adequacy of structural members subjected to blast loading using general limits in attempting to check the structure's strength and regularity. The analysis was based on load combinations and damage criteria according to the Unified Facilities Criteria which are general design approaches suitable for civil design applications in forecasting blast loads and structural system responses. The overall behavior of this structure was simulated based on a dynamic analysis by the direct simulation approach, which was chosen for modeling blast loads using the Friedlander blast load equation, and the simpler, less expensive, more accurate, and realistic A.T.‐BLAST model to deduce the simplified blast‐wave overpressure profile. The material nonlinearity at a high strain rate using the Johnson‐Cook strength and concrete plasticity damage model is studied dynamically using ABAQUS finite element code to simulate the explicit dynamic nonlinear analysis. The overall response of the proposed numerical model was evaluated by estimating the adequacy of structural members, considering the blast load as the initial cause of failure, such as axial plastic strain, internal forces limits, maximum deformation, support rotation, demand‐capacity‐ratio (DCRshear/moment), drift index and material damage model. The position of the explosive charge played an important role in determining the rate at which the structural element begins to plastic strains, displacements, moments, or rotations beyond the limits, and then key elements should be considered in structural design against progressive collapse. Results showed that steel members exhibit early indicators of failure, such as buckling necking, shear tearing, or plastic hinges, whereas concrete slabs break up immediately due to brittleness. DCRmoment values successfully showed the columns in which the first plastic joint can occur, whereas DCRshear values signaled the onset of shear failure at connections. Besides, plastic hinges played an important role in dissipating energy and preventing total structural collapse via the Strong Column‐Weak Beam design concept, which appears repeatedly in this study. The structure is a well‐designed and ductile building capable of supporting higher loads and is considered to be repairable and intact.

Inelastic behavior of diagonally reinforced coupling beams confined with steel fibers

Experimental studies were conducted to analyze the plastic rotation capacity and the effect of replacing transverse reinforcements with steel fibers in diagonal reinforced concrete coupling beams. Six specimens were planned, and the steel fiber reinforcing index and total area of transverse reinforcements were the main variables. Reverse cyclic loading tests were conducted to confirm the seismic performance of the coupling beam. The results showed that the plastic hinge rotation capacity increased and the buckling point of the diagonal reinforcing bars was delayed as the steel fiber reinforcing index increased. An analysis of 78 specimens and the results of previous studies confirmed that ductility improved when the confinement effect of the steel fiber was considered. Application of an equation for ductility requirements reflecting the confining stress of steel fiber reinforced concrete confirmed that the amount of transverse reinforcement could be reduced.

Development and experimental study of a novel rotational metallic damper

As passive control technology advances and building forms become increasingly diversified, traditional axial and shear dampers may no longer meet diverse structural application requirements. This paper introduces a novel rotational metallic damper, i.e. rotational steel rod damper (RSRD), as an alternative engineering solution. The RSRD comprises three steel plates rotating around a central pin and four low yield point steel rods as energy dissipators. The input seismic energy can be dissipated in the form of plastic rotation of the RSRD. Initially, the structural form, working mechanism, and design approach of the RSRD are presented. Subsequent cyclic quasi-static tests on two RSRD specimens under varied loading protocols demonstrated satisfactory energy dissipation capacity, with an equivalent viscous damping ratio exceeding 0.47. The cyclic behavior, rotational strength, and cumulative plastic deformation capacity are discussed following the tests. A finite element (FE) analysis on the RSRD using ABAQUS is conducted to further investigate its performance. A comparison between the hysteretic behavior and failure mode of tested and simulated results is presented to validate the FE model. Additionally, two new structural forms, with linear and arc-shaped weakening on the steel rod, are simulated and compared with the original. FE results indicate that the arc-shaped weakening of the steel rod effectively avoids plastic strain concentration, showcasing superior low-cycle-fatigue performance. Finally, nonlinear time history analyses on two RC frames, with and without RSRD, reveal that structural and non-structural damage can be controlled under the maximum considered earthquake (MCE) by utilizing RSRDs.

Students Matriculating into Integrated Plastic Surgery: Are all Medical Schools Equal?

Becoming a craniofacial/pediatric plastic surgeon depends on completing a plastic surgery (PS) residency. As medical school curricula for PS exposure are highly inconsistent, the authors investigated whether there was an association between the presence of PS elective rotations and/or home programs in medical schools with the proportion of students matriculating into integrated PS residency. A list of 198 medical schools was compiled from the Association for American Medical Colleges and the American Association of Colleges of Osteopathic Medicine. Plastic surgery residency programs were identified by the American Society of Plastic Surgery and the American Council of Educators in Plastic Surgery. Plastic surgery elective rotation offerings and recent matches (2021-2022) were obtained from school websites. Mean proportions of students matriculating into PS between schools that did versus did not have PS elective rotations and/or home PS residency programs were compared. One hundred fifty-nine medical schools were included. Seventy-seven of 159 (48%) had both PS elective rotations and home program(s), 63/159 (40%) offered PS elective rotations only, and 19/159 (12%) had neither. The mean proportions of students matriculating differed significantly ( P <0.001) among schools without PS electives or a home program [0.09%, 95% confidence interval (CI): -0.04% to 0.21%), PS elective only (0.51%, 95% CI: 0.25%-0.77%), and both PS elective and home program(s) (1.14%, 95% CI: 0.92%-1.37%). The presence of elective PS rotations and a home PS residency program significantly increase the chances of matriculation into integrated PS residency programs.

Cyclic behavior of high-strength steel beam-to-column welded flange-bolted web connections

Four Q690 high-strength steel beam-to-column moment connections, which use welded joints between beam and column flanges as well as a bolted beam web to the column flange, were tested under cyclic loading. The effects of beam-to-column welding details and panel zone strength were studied. Two pairs of welded flange details were incorporated, including the Chinese code-specified complete-joint-penetration (CJP) welded connections with backing plates where the bottom backing plate is reinforced by a fillet weld, and enhanced CJP welded connections with backing plates removed, weld roots backgouged, and further reinforced by fillet welds. Three panel zone thicknesses were designed to characterize strong, intermediate and weak panel zones, respectively. The test results show that backing plates should be removed in these moment connections to prevent brittle weld fracture, but still rendering only limited plastic hinge rotations in the order of 0.01–0.02 rad in the beam end before ductile fracture of the beam flange. The panel zone, however, survived even after a plastic shear rotation of 0.03 rad, demonstrating much higher plastic deformation capacity than the beam plastic hinge. This suggests that ductility can be exploited in 690 MPa high-strength steel panel zones, but not reliably in 690 MPa steel beams.

Investigation of Linear and Nonlinear Behaviour of Reinforced Concrete Column Exposed to Corrosion Effect for Different Damage Limit Levels

The high performance of reinforced concrete structural elements under the effects of lateral loads such as earthquakes is of great importance in terms of minimizing the loss of life and property that may occur due to earthquakes. One of the parameters affecting the earthquake behavior of a reinforced concrete structure is the corrosion effect. The aim of this study is to investigate the behavior of reinforced concrete columns exposed to different corrosion levels for different durations within the damage limits. In this direction, it is aimed to perform linear and nonlinear analysis of reinforced concrete columns in 5 different corrosion scenarios. In the study, nonlinear analyzes of the column were made using ANSYS software, the data obtained were determined for different damage limit levels and compared with the section analysis. Because of the study, moment-curvature relations, lateral load-horizontal displacement relations, bending ductility and plastic rotation capacity of the reinforced concrete column were determined for each corrosion scenario.

Experimental investigation on cold-formed steel hollow sections with moderate heat treatment under combined compression and cyclic lateral loads

This paper presents an experimental investigation on cold-formed steel rectangular and square hollow sections (RHSs and SHSs) with subsequent heat-treatment under combined compression and cyclic lateral loads. A total of 25 specimens designed with different parameters, including slenderness ratios (b/t and d/t) and axial load ratio (n) ranging from 0 to 0.5 were tested. Material tests were carried out to confirm the material ductility requirements stated in Eurocode being reached. Failure modes, moment-rotation curves, secant stiffness, energy dissipation and plastic hinge length presented were analysed. In addition, deformation capacity was evaluated in terms of maximum and ultimate rotations. The comparison results between plastic rotation limits proposed by design codes and the test results indicate that AISC 341-16 is more suitable for the design of cold formed hollow sections with moderate heat treatment under this investigation, though the recommended reduction factor of axial load might be conservative.

Experimental study and numerical analysis on the failure mode of staggered truss framing system

To investigate the seismic performance of staggered truss framing system under different failure modes, two trusses were designed according to the capacity design method. Then, two models with a scale of 1/2.5 were made and subjected to quasi-static tests. The hysteresis curve, stiffness, energy dissipation, and ductility coefficient of the two models were analyzed. The test results show that the specimen designed for chord failure has better seismic performance than that designed for diagonal web failure. The ultimate drift ratios of the two specimens are both less than 1.5%, indicating that the deformation ability of the staggered truss is insufficient. By analyzing the relationship between the plastic hinge rotation and the drift ratio of the truss, it is suggested that the limit value of the drift ratio of the staggered truss framing system should not exceed 1.5%. The yield-bearing capacity calculated by considering the composite effect of the chord and floor slab is closer to the test results than that calculated without considering the composite effect, indicating that the composite effect of the chord and floor slab should be considered when designing the trusses. Through the numerical analysis, it is recommended to take a minimum amplification factor of 1.3 for the internal force of web members to realize the purpose of chord failure.

Seismic performance of very short links in eccentrically braced substructures

Research on the seismic performance of eccentrically braced hybrid frames indicates that utilizing very short links can enhance structural stiffness and load capacity. However, there is limited investigation into their effectiveness within eccentrically braced substructures featuring flush end plate bolted connections. This study involves an experimental and numerical investigation to understand the behavior of very short shear links with flush endplates bolted connections in the substructure. An experimental study of 8 specimens was carried out, and the variables studied included loading protocol, links length ratio, flange thickness, and end plate thickness. The experimental results showed that the co-design methodology for flush endplates and bolts of very short links exhibited acceptable performance. Very short shear links bolted with flush endplates demonstrated an average overstrength coefficient of about 1.8 and an ultimate plastic rotation angle above 0.12 rad. Numerical analysis explored the effects of length ratio, web height-to-thickness ratio, and flange width-to-thickness ratio on overstrength behaviors and yield capacity of very short links. The analysis indicated that the length ratio was crucial in determining overstrength coefficients and the yield capacity of very short links. The study established modified formulas that consider the impact of different variables to more accurately determine overstrength behaviors and yield capacity based on formulas in the Chinese code.

Overstrength and plastic rotation of two-segment replaceable link with separated splicing plate

To enhance the seismic performance and post-earthquake reparability of traditional eccentrically braced frame structures, this study proposes a two-segment replaceable links with separated splicing plate: one featuring specimens with standard holes in the separated splicing plate (TSRL1), and the other featuring specimens with slotted holes in the separated splicing plate (TSRL2). Through cyclic loading tests, it was observed that the hysteresis curves of the links exhibited a relatively complete response, characterized by plastic rotations of 0.09 rad and 0.17 rad respectively. The overstrength coefficient ranged from 1.66 to 2.08, indicating commendable performance in terms of both overstrength and plastic deformation capacity. Subsequently, finite element simulations of the link were conducted using ABAQUS. Based on the congruity between simulation and test results, a parametric analysis was performed to determine the optimal seismic performance of the two-segment replaceable links with separated splicing plate by varying the length of the energy dissipation zone and hole type of the bolts.

Revision Rates in Cosmetic Plastic Surgery with and without Resident Involvement.

Changes in surgical education have caused concern over residents' preparedness for independent practice. As the field of otolaryngology requires such a wide breadth of expertise, ill preparation becomes especially costly. This study explores how the presence and participation of a postgraduate year 3 (PGY3) otolaryngology resident in surgery impacts revision rates and operating time as gauges for the resident competency and indirect training costs. A retrospective chart analysis of patients who underwent cosmetic plastic surgery at sites for PGY3 otolaryngology residents' facial plastic surgery rotations was conducted. Residents performed one side of bilateral procedures (eg, blepharoplasties) and approximately 50% of midline procedures (eg, rhinoplasties). Chi-squared testing and odds/risk ratios were done to assess the effect of resident involvement on revision rates. Operating time was compared using t tests. When a resident was involved in cosmetic surgery, the revision rate was 22.2% compared with 3.6% without. The likelihood of a future revision surgery was 7.57 times higher when a resident participated in the original operation. Resident involvement was not a statistically significant predictor of exceeding the allotted operating time. The revision rate of cosmetic surgery was much higher when a resident was involved. Otolaryngology residents would benefit from increased facial plastic and reconstructive surgery training. As a response to this analytical study, this clinical rotation was moved to be offered at a later stage of postgraduate surgical training to allow residents to gain more experience and be better set up for success in the rotation.

Experimental and Numerical Analysis of a Temporary Bridge Connector Consisting of an Upper Bearing Block–Lower Pin Configuration

In this study, the structural details of a hinge connection for steel girder segments were developed to improve the process of rapid and easy construction. In the connector developed in this study (referred to as the “speedBridge” hereafter), the compression load exerted on the upper flange is resisted by two bearing blocks in contact with each other, and the tensile force on the bottom flange is resisted by the hinge structure installed at the lower part of the steel girder. The structural behavior of the developed connection was investigated experimentally. It was shown that the developed connection details could develop an excellent connection plastic rotation of 5% rad without fracture. The test specimen developed initial stiffness in accordance with elementary beam theory for a supported beam. The maximum load reached 110% of the plastic moment of the beam. Finite element analysis was conducted to comprehend the load transfer path, and the results demonstrated that the hinge connection exhibited sufficient stiffness and strength, exceeding the bending capacity of the beam under tension without any signs of the failure modes considered in the design procedure.

A new performance‐based seismic design method using endurance time analysis for linked column frame system and a comparison of structural systems and seismic analysis methods

SummaryThis paper presents a new performance‐based seismic design method for the design of repairable linked column frame (LCF) and linked column system (LCS). Currently, the biggest problem of these systems is the lack of a simple and practical design method that leads to the design of optimal models with sufficient seismic capacity. The interaction of the primary and secondary systems, changing the lateral load pattern during an earthquake, and the implementation of the target performance objectives have complicated the design of these systems. The evaluations carried out in this research show that the rotation of link beams must be controlled in the design. Therefore, the ultimate plastic rotation of links is determined to be 0.01 rad for the seismic intensity of design base earthquake and 0.015 rad for maximum considered earthquake. The results show that the models designed using the presented method are optimal, have sufficient seismic capacity, and achieve the target performance objectives. In addition, although previous researches have shown that these systems have a suitable seismic behavior, their seismic behavior have not been compared with other structural systems. Comparing can show the behavioral characteristics of a new structural system; hence, the elastic and plastic behavior of the LCF and LCS models have been compared with other common steel structural systems using all analysis methods. Moreover, in the presented method for the design of LCF and LCS systems, nonlinear time history analysis using the endurance time method (ETM) is used, and due to the newness of the endurance time method, its results are compared with the median results of nonlinear time history analysis at different seismic hazard levels and incremental dynamic analysis (IDA), in 45 samples. The results show that the endurance time analysis is a reasonable and efficient method, and in this comparison, the difference between the results of ETM and IDA methods is 6% on average.