Reinforcement Arrangement Research Articles

Research on the relationship between comprehensive characteristics of cracks and stiffness of RC beams

The relationship between crack comprehensive characteristics and the stiffness of RC beams is investigated through experimental tests and numerical simulations. A synthetic parameter, the surface damage ratio (SDR), is proposed to represent the comprehensive characteristics of cracks, including crack width, length and location. Crack propagation in RC beams is simulated using a dual-damage parameter plastic damage model. A method for calculating the width and length of cracks is developed based on integral point strains and element equivalent length. The accuracy of this method is verified by comparing it with the results of four-point bending tests on RC T-beams and rectangular beams. Correlation analysis indicates that the cracks in different zones have varying impacts on beam stiffness, with crack length in the bending area and crack width in the shear area having a greater impact than others. To consider the comprehensive characteristics of cracks and their impact on beam stiffness, the SDR, the ratio between the entire crack area and the intact area of the beam surface, is proposed. The proposed parameter is shown to increase linearly with load, resulting in beam stiffness degradation following a power law. The accuracy and applicability of the proposed SDR and its correlation with load and stiffness are verified through load tests on rectangular beams with different reinforcement ratios using Cervenka’s test. Parameter analysis has shown that the section modulus, concrete strength, reinforcement arrangement, and ratios significantly influence how beam stiffness varies with SDR. The presented simulation model for concrete crack evolution, combined with the synthetic parameter of crack characteristics, and the correlation analysis, provide a valuable approach for the safety evaluation of concrete beams during their service life.

Experimental investigation of the seismic performance of corroded reinforced concrete coupling beams

In this study, a seismic performance assessment of six reinforced concrete (RC) coupling beam specimens with accelerated corrosion is conducted by combining accelerated corrosion methods with quasistatic loading tests. A detailed comparison of the corrosion damage, failure modes, and mechanical performance differences of the coupling beam specimens under different corrosion levels is presented. The degradation patterns of the coupling beam seismic performance are revealed through analyses of the hysteresis behavior, stiffness degradation, energy dissipation capacity, and proportions of bending, shear, and slip deformations in relation to the corrosion level. The experimental results indicate that with increasing corrosion level, the load-carrying, deformation, and energy dissipation capacities of the coupling beams continuously decrease. The cracking pattern of corrosion-induced cracks is influenced by the reinforcement arrangement, with diagonal reinforcement causing cracks to propagate diagonally. The nonuniform distribution of corrosion leads to asymmetric loading in coupling beam specimens with higher corrosion ratios, significantly weakening the load-carrying and energy dissipation capacities and making the specimens more prone to sudden brittle shear failure without warning. Corrosion-induced damage degrades the shear capacity of the coupling beams, increasing the proportion of shear deformation.

Influence of subgrade spatial variability on strain-alleviating ability of geogrids and rutting life in flexible pavement

This study employs the Random Field Finite Difference Analysis to assess how subgrade spatial variability impacts geogrid reinforcement’s strain-alleviating ability and the reinforced pavement’s rutting life. The geogrid’s abilities to reduce critical strains are evaluated using a strain-alleviating ratio and compared between deterministic and spatially variable scenarios. The analysis involves six geogrid reinforcement arrangements, considering two kinds of geogrid stiffness (G1 and G2) and three typical positions: top (L1), mid-depth (L1-2) and bottom (L2) of the base course. Key findings include: (a) Subgrade spatial variability significantly amplifies mean critical strains and leads to irregular strain and stress distributions, which in turn impacts the strain-alleviating ability of the geogrid reinforcements and potentially changes the optimal geogrid position. (b) The impacts of subgrade spatial variability on the geogrids’ strain-alleviating ability vary with the type of critical strains, the geogrid position, and the coefficient of variation and scale of fluctuation of subgrade modulus. When the geogrid is located at L2 (G_L2), its ability to alleviate critical subgrade strain is significantly compromised. (c) The adverse effect of subgrade spatial variability on the rutting life of G_L2 reinforced pavement is significant and can be mitigated by homogenising a very thin sublayer at the subgrade surface.

Finite element modelling of continuous fiber–reinforced composites produced by automated manufacturing

Abstract With the advent of automated, continuous filament placement technologies, the possibilities for reinforcement placement in composite manufacturing have been further expanded, as the reinforcement path can be continuously varied within the layer. This allows far more efficient structures to be created, resulting in a further reduction in the weight of the structure compared to conventional composites. At the same time, this manufacturing freedom also poses a major challenge for the structural design of composite components, as simulation methods based on meso-level homogenization are mostly not usable due to the lack of periodicity of the reinforcement structure. In our paper, we have established a structural modelling method using finite element analysis (FEA) for fused filament fabrication-based additive manufacturing of continuous fiber–reinforced composites. For modelling the reinforcement structure properly, we used the base-coordinate sweep (BCS) modelling method and for capturing progressive failure mechanisms we used Ansys LS-Dyna with the MAT54 material card. Based on the simulations and tests performed, we demonstrated that the method we present is suitable for the engineering modelling of continuous fiber–reinforced 3D printed composites.

Experimental investigations on the flexural behavior of UHPC wet joints for UHPC light-weight rigid frame arch bridges

Wet joints are critical parts of prefabricated ultra-high-performance concrete (UHPC) light-weight rigid frame arch bridges (LWRFAGs), so their mechanical behavior is important to the structural design and applications of these arch bridges. To explore suitable joint configurations and reinforcement arrangements for connecting UHPC components or arch ribs of a practical UHPC LWRFAG, this paper experimentally investigated flexural behavior of several prefabricated UHPC joint beams with various kinds of wet joints through four-point bending tests. Firstly, four different UHPC joint beams with different joint configurations were designed, including (i) vertical joint; (ii) rhombus joint; (iii) vertical joint with top and bottom strips; and (iv) rhombus joint with top and bottom strips, and their flexural performance were compared with a complete UHPC beam. The experimental results revealed that UHPC joint beam employing the rhombus joint with top and bottom strips exhibited superior flexural behavior and cracking resistance among four UHPC joint beams. Subsequently, to achieve optimal and robust joint configurations, bending performance of one complete UHPC beam and three large-scale UHPC joint beams with rhombus joints but different reinforcement arrangements were experimentally studied. It is observed that the beam with the welded twist reinforcements (specimen V-4) shown optimal flexural performance and cracking resistance. Finally, to explore the load transfer mechanism and effects of reinforcement parameters on flexural behavior of specimen V-4, the parametric studies were comprehensively performed using finite element analyses (FEA). This study could serve as both the experimental and theoretical reference for flexural design of UHPC beams with the rhombus wet joints.

Response of back-to-back mechanically stabilized earth walls under different static loads and reinforcement arrangement

Response of back-to-back mechanically stabilized earth walls under different static loads and reinforcement arrangement

Improved corrosion resistance of hydroxyapatite-reinforced plasma electrolytic oxide coatings on AZ31 alloy from one-step and two-step fabrications

The improved corrosion resistance of AZ31 alloy by plasma electrolytic oxidation (PEO) counteracts its apatite-forming ability. To overcome the issue, apatite-containing coatings were fabricated. One-step and two-step fabrications were compared to incorporate the nanoparticle hydroxyapatite (HA) in the coating and to evaluate their effect on the corrosion resistance. The corrosion resistance was evaluated by polarization test and EIS measurement in 0.9% NaCl solution. The electron microscopy and chemical analysis revealed that the HA particles were dispersed in the one-step coatings, while an interspersed HA distribution was observed in the two-step coatings. The dispersed particles enhanced the coating’s hardness from 490 to 554 HV. In the two-step coatings, the HA particles mainly accumulated inside the pores, reducing the coating porosity down to 3.9%. The one-step coatings were more stable in the corrosive solution, offering a remarkably higher corrosion resistance, than the two-step coatings. Moreover, the one-step coating required a shorter (half) processing time (10 min) than the two-step process (20 min) to achieve a similar order of corrosion current density of 10−7 A cm−2. The results demonstrated that the arrangement of reinforcement in the PEO coatings and its effect on the corrosion resistance can be adjusted.

Cracking behavior of segmented-casting joint in steel-UHPC composite bridge deck system: Experiment and numerical simulation

The cracking of the pre-/post-casting UHPC joint in the steel-UHPC composite bridge deck system can lead to continuous tensile damage in the UHPC layer, reducing its ability to stiffen the steel deck. This study aims to clarify the cracking mechanism of the segmented-casting UHPC joint, and to provide design recommendations for cracking control. Axial tension tests on full-scale composite deck specimens were conducted, in which the influence of with and without joint, and varying reinforcement ratios on cracking response were identified. Moreover, the nonlinear numerical model for the composite deck, where the UHPC-UHPC interface was simulated in three methods, i.e. unbonded case, cohesive zone model (CZM), and perfectly bonded case, was developed and validated to simulate the crack initiation and propagation of the UHPC layer. Based on the validated numerical model incorporating CZM, improving the bond strength of CZM is more effective in controlling crack opening at the interface than increasing the failure displacement. Finally, optimized reinforcement arrangement and joint shape recommendations were provided to enhance construction convenience, minimize stress concentration, and limit crack opening.

Analysis of Pile Foundation for Hospital Buildings

Pile foundations are widely employed to provide support for bridges and various structures, ensuring the safe transfer of structural loads to the ground while preventing excessive settlement or lateral movement. They excel in transferring structural loads from weaker or compressible soil layers to the stronger, more stable soils and rocks beneath. Pile foundations constitute an integral component of a structure.  In this research work the foundation of the hospital (G+6) was design by the pile foundation. We have used M25 grade of concrete for the preparation of design mix. The characteristic strength and load bearing of soil was tested by Plate load test and other materials tested by slump cone test , aggregate Impact Value test cement compressive strength test (cement fineness test construction water PH value . The expected result of SBC is 20000kg approximate.  Project reports typically encompass introductions and problem definitions, along with literature reviews pertinent to the project. They detail the study area's location and the project site, as well as providing concise information about the equipment utilized on- site.  Additionally, it covers crucial tasks such as centerline marking, boring, reinforcement placement, concrete pouring, excavation, and chipping of pile caps.

Interlaminar tensile properties of raw and carbon fiber‐wrapped additively manufactured polyetherimide

AbstractHigh‐performance engineering thermoplastics are important emerging materials, particularly when processed using additive manufacturing technologies. One of the most important among these is polyetherimide, also known as PEI or ULTEM. Using the fused filament fabrication (FFF) additive manufacturing (AM) process to form this material is a good option, but it is difficult to control the properties in some cases due to the very high processing temperature compared with most engineering thermoplastics. One way to “even‐out” the properties is to wrap the specimens in continuous glass or carbon fibers embedded in a thermosetting matrix, as this allows strategic placement and orientation of reinforcement. This also complements the natural structure of the FFF‐manufactured materials, helping to minimize the amount of additional weight that needs to be added to a part. To further knowledge in this area, the present study explored and compared the interlaminar tensile strength of FFF‐processed PEI/ULTEM 9085 specimens and compared them with ones wrapped in carbon fibers with a 2‐part resin matrix. Experiments were performed in accordance with the guidelines given in the ASTM D6415 standard and replicated five times. Variations were introduced in thickness of the specimen and raster angle during the manufacturing process to identify the significant impact of the failure. The results show a fall in interlaminar tensile strength with increasing specimen thickness and a very large effect from natural printing defects in the samples. The carbon fiber wrap decreased the ILTS but made the results far more consistent between experimental runs. This study provides a good, replicated dataset on the performance of raw and fiber‐wrapped FFF‐processed ULTEM 9085 and gives insights into the structural behavior of the material that will be useful for use in design decisions and material selection.Highlights Polyetherimide, also known as PEI/ULTEM, is a high‐performance engineering thermoplastic. Explored the interlaminar tensile properties (ILTS) of this material using ASTM D6415. Raster angle, thickness, and use of fiber wrap were experimental parameters. Fiber wrap was found to have little effect on strength but made results more consistent. Results are useful for material selection and design decisions using PEI.

Fatigue and monotonically-loaded reinforced concrete specimens subjected to partial area loading

The degradation of concrete structures is often due to the continuous application of compressive fatigue loads. Understanding of concrete behaviour in different environmental conditions and under especial fatigue loading arrangements, particularly in cases where the loaded area is smaller than loaded element, herein referred to as partially loaded area, is of utmost importance to make a realistic prediction of the concrete fatigue life for a reliable design of civil engineering infrastructure. This paper focuses on investigating the fatigue performance of reinforced concrete specimens subjected to partially loaded areas, considering the influences of steel fibres, reinforcement arrangement, and the environmental factor of water submergence. A typical example of a partially loaded concrete component subjected to fatigue loading is circular spread footings used as concrete foundations for typical wind turbines. In these types of elements, the compressive strength of the concrete can be enhanced due to the confinement provided by way of lateral restraint stemming from surrounding concrete and reinforcement. However, design codes primarily address static loading and lack specific criteria for fatigue loading in these partially loaded regions. To address this research gap, results from a comprehensive experimental study, which in total included 111 concrete specimens subjected to monotonic loading and 25 specimens tested under cyclic loading, were used to study this problem. The investigation aimed to evaluate the effects of steel fibres and reinforcement arrangement on both static and fatigue capacity. Additionally, the impact of submerging concrete structures in water on their fatigue performance was examined, revealing a decrease in their fatigue life. The experimental results demonstrated that the presence of steel fibres and splitting reinforcement significantly increased both static and fatigue capacity. Most current design codes neglect the environmental factor of water submergence, leading to reduced fatigue capacity in concrete structures. Consequently, the validity of the design codes DNV-OS-C502 and fib Model Code 2010 was evaluated, and a new environmental factor for partially loaded areas subjected to cyclic loading is proposed. To evaluate the experimental results and understand the mechanical response, nonlinear finite element analyses were conducted using a smeared-crack continuum modelling procedure coupled with high cycle fatigue material models to assess its applicability for estimating fatigue performance of partially loaded reinforced concrete elements. It was found that a plane stress modelling procedure was capable of estimating fatigue capacity for dry concrete components, however, overestimated the fatigue capacity of wet concrete components.

Application of BIM Technology in Structural Design of Prefabricated Building Based on Big Data Simulation Modeling Analysis

Aiming at the complex steel bar layout problem in prefabricated building, this research proposes a structural design method of prefabricated building based on big data simulation modeling building information modeling technology. It includes the reinforcement arrangement model based on agent path planning, the intelligent reinforcement arrangement of frame based on artificial potential field method and path optimization, and the modeling of Building information modeling. When analyzing the reinforcement arrangement effect of beam column joints in Prefabricated building, the calculation time of top corner joints is the shortest, 76.8 seconds, while that of middle layer joints is the longest, 141.7 seconds. In direction Y and direction X, differential evolution has the longest calculation time, 27s and 26.57s respectively, while particle swarm optimization algorithm has the shortest calculation time, 2.84s and 3.02s respectively. The algorithm designed through research is significantly superior to other algorithms in terms of computational time. In general, through building information modeling technology and big data simulation modeling, this study realized the collision free layout of rebar in beam column joints of prefabricated building. This improves the speed and efficiency of deepening design, and provides a new solution for structural design of prefabricated building.

The Effect of Type of Reinforcement, Type of Glue and Reinforcement Place on Mechanical and Physical Properties of LVL

This study investigated the effect of the reinforcement type, glue type, and reinforcement placement on the mechanical and physical properties of LVL. In the study, the glues used were phenol- formaldehyde (FF), epoxy (EX), and polyurethane (PU), while reinforcement materials used were glass fiber, basalt, jute, and cotton fabric. The following three reinforcement combinations were applied: the first was on the bottom surface, the second was on the first adhesive line at the bottom, and the third was on both the bottom and the first adhesive line at the bottom. As part of the study, researchers manufactured 9-layer laminated veneer lumber (LVL) using alder veneers for the surface, and poplar veneers for the middle layers. They produced a total of 39 different combinations of LVL. The mechanical and physical properties of the produced samples were determined. According to the test results, bending strength (BS), modulus of elasticity (MOE), oven-dry specific gravity, and equilibrium moisture content of samples were higher with FF than with other glues. While the samples with EX glue provided the lowest values in water absorption and thickness swelling tests, glass fiber-reinforced samples provided the highest mechanical values. In addition, the samples having reinforcement on the bottom surface provided higher BS and MOE values.

Changes in air permeability of restrained expansive concrete under drying condition: contribution of expansive strain

Restraining the expansion of expansive concrete with embedded rebars can exert chemical prestressing, which may affect the durability of concrete structures. This study aims to investigate the durability performance of expansive concrete by understanding the mechanism of air permeability changes while considering the variations in reinforcement arrangements and concrete dimensions. The Torrent’s air permeability test was used to non-destructively evaluate the disparity in air permeability changes of expansive and normal concrete during the drying processes from 28 to 182 days. Additionally, expansive strain changes were continuously monitored to investigate chemical prestress. The experimental test results suggest the immense effect of the change in expansive strain on the air permeability of concrete. This study proposes that the change in microstructure owing to the loss of expansive strain may cause an increase in air permeability. The loss of expansive strain is a distinguished feature that differentiates the mechanism of air permeability changes in expansive and normal concrete. These findings suggest the possible improvement in the durability performance of expansive concrete in cases where the loss of its expansive strain can be controlled.

LAPAROSCOPIC SUGARBAKER TECHNIQUE FOR PARAOSTOMAL HERNIAS. HOW WE DO IT

Abstract Aim To delineate the critical steps involved in Sugarbaker laparoscopic paraostomal hernia repair. By providing a detailed understanding of these steps, surgeons can improve their procedural proficiency, leading to enhanced patient outcomes and reduced postoperative complications. Material and Methods We compiled several videos to identify and highlight the critical steps to performing and adequate Sugarbaker laparoscopic repair for paraostomal hernias. Results The critical steps in Sugarbaker laparoscopic paraostomal hernia repair were identified and categorized into preoperative, intraoperative, and postoperative phases. These steps include patient selection, stoma site, trocar placement, dissection and reduction of herniated contents, mobilization of the colon, closure of the hernia defect, measurement according to anatomical landmarks for mesh preparation, placement of mesh reinforcement. Emphasis was placed on meticulous technique, anatomical landmarks, and avoidance of potential pitfalls. Conclusions Sugarbaker laparoscopic paraostomal hernia repair is a technically demanding procedure requiring adherence to critical steps for optimal outcomes. Surgeons should prioritize thorough preoperative planning, precise intraoperative technique, and vigilant postoperative care to minimize complications and achieve successful hernia repair. Further research and refinement of surgical techniques are warranted to continually improve the efficacy and safety of this approach.

Slab design combining interlocking blocks with a structural sheet

The construction of structural slabs is one of the more complex, costly, time consuming, and hazardous processes in constructing buildings. This is mainly due to the on-site formwork placement, reinforcement arrangement, and concrete pouring — all required for commonplace slab designs. In theory, industrialization-ready slab designs pose a promising path towards overcoming these challenges. However, designs that can deliver on this promise are not yet fully developed. Here we present a new structural slab design fit for an industrialized construction framework. It is made of interlocking blocks that are adhesively bonded to a structural sheet. We first present the slab design, detail the rationale behind it, and illustrate its inherently quick and accurate construction technique. Then, using numerical simulations, we examine the structural action of the proposed design and how it compares with that of a typical reinforced concrete slab with the same material quantities. We find that the structural performance of the proposed design is competitive with that of a reinforced concrete slab in terms of stiffness, carrying capacity, and ductility. Our results show that the inherently superior constructability of the proposed design is achieved without critical sacrifice of performance, thus underscoring its promising potential as a viable structural design alternative.

Numerical analysis of the behaviour of a concrete floor in a steel-framed structure subject to a traveling fire

This paper presents a finite element model for a multi-story structure subjected to traveling fire. The structure selected has been previously investigated in experimental studies. The study investigates the effect of the number and positions of the panels exposed to fire on the fire behavior of the composite floor in the structure. Parameter analyses were conducted, including floor thickness, reinforcement arrangement, loads, position and number of panels exposed to fire, and traveling fire. The study shows that there are three different patterns of membrane action: ring type, diagonal U type, and opposite side U type. The moment and axial force of the steel beam near the fire panel increase gradually, while the internal force change of the steel beam at a distance from the panel exposed to fire is relatively small. The axial force of the edge and corner columns changed more significantly compared to the axial force of the middle column. Furthermore, the displacement, fire resistance, failure mode, and membrane action of the floors depend primarily on the position of the panels exposed to fire, the traveling fire, and the interaction among members.

Punching shear tests in flat slabs supported on re-entrant corner columns

The punching strength and deformation capacity of slab-column connections is governing for design at ultimate limit state of flat slabs. This phenomenon has been investigated since decades with experimental programmes in an effort to derive empirical or mechanical design approaches. Such efforts, due to the complexity of the phenomena, have mostly been addressed to axisymmetric inner slab-column connections, which correspond to the simplest academic case and are not directly covering a large variety of practical situations. Although some tests are also available for other configurations, such as edge or corner connections, no experimental evidence is found on relevant cases for practice such as re-entrant corner columns. The lack of experimental data in this latter case raises questions on the design of such connections, as extrapolating results from other cases is not a simple task due to the complexity of the phenomena implied (such as redistributions in the shear field and moment transfer between slab and column). In order to advance the knowledge on the response of re-entrant connections and to provide a sound design approach for them, this paper presents the results of an investigation specifically addressed at this case. To that aim, seven specimens were tested under different conditions, varying the load eccentricity, flexural reinforcement and shear reinforcement arrangement at the edges. The tests were instrumented with refined measurements, allowing to understand in a detailed manner the response of the slabs during testing in the shear-critical region. The experimental results are later compared to current design codes, leading to a number of conclusions with practical relevance. Finally, on the basis of the knowledge acquired from the tests, a mechanical approach is proposed based on the Critical Shear Crack Theory to assess the punching response. This approach is shown to lead to accurate and reliable predictions of the punching strength, improving those of current design codes.

Dynamic behavior and characteristics of geogrid-reinforced sand under cyclic loading

This paper evaluated the benefits of geogrid-reinforced sand samples and investigated the effect of different factors contributing to the dynamic behavior, which included the geogrid type, arrangement of reinforcement, confining pressure and dynamic stress amplitude. Four geogrids of different aperture geometries (two biaxial geogrids and two triaxial geogrids) produced by 3D printing technology were used. The research was experimentally carried out by conducting dynamic triaxial tests to investigate the axial cumulative strain, dynamic elastic modulus and damping ratio of the samples. The test results demonstrated the potential benefit of installing geogrids in subgrade soils. Less axial cumulative strain, damping ratio and larger dynamic elastic modulus were measured under cyclic loading for geogrid-reinforced samples compared to those unreinforced samples. The geogrid type and reinforcement arrangement had noticeable impacts on the samples’ dynamic performance. Of the four model geogrids tested, the triaxial geogrid with triangle aperture performed consistently better than the other three. Under large confining pressures and dynamic stress amplitudes, there was no appreciable improvement in the dynamic performance of the samples reinforced with the two triaxial geogrids. The results also showed that the double reinforcement arrangement consistently yielded better improvement. This study explored preliminarily the feasibility of applying 3D printing technology in geotechnical model tests, which shed light on the understanding of dynamic response of geogrid-reinforced soil and the optimization of geogrids.

Exploration and Application of Three-stage Strengthening Mode based on Massive Open Online Course to Improve Students’ Competence in Electrocardiogram Interpretation Skills

Electrocardiogram (ECG) is a widely common diagnostic test in clinical practice. However, research has shown that residents and medical students cannot analyze ECG skillfully. In this study, we explore a three-stage strengthening mode based on massive open online course (MOOC) to improve students’ competence in ECG interpretation skills. We carry out the first stage in a diagnostics course, in which instructors adopted online and offline blended mode for the teaching method of ECG with clinical medicine students in grade 2018 based on MOOC. We compare scores of ECG interpretation skills for 91 students in grade 2018 with 81 students in grade 2016 to evaluate the effect. The second stage concerns studying internal medicine, in which we divide students in grade 2018 into two groups with 49 students in group A and 42 students in group B. Group A strengthened their ECG interpretation skills when learning about heart diseases. The third stage pertains to rotation in the internal medicine department in the internship period. Some students in group A continued to receive intensive training. Students in group B had no reinforcement arrangement in the second and the third stage. Students in grade 2018 took graduation tests at the end of their internship. We use the scores on ECG interpretation skills in the graduation examination to evaluate the strengthening effect between group A and group B. The result of the first stage shows that scores on ECG interpretation skills in the final exam in grade 2018 were 19.32 ± 4.62 points, which is higher than those of grade 2016, whose points were 16.89 ± 5.30 (total scores in both grades were 30 points). Difference is statistically significant. Scores on the graduation examination in group A were 38.89 ± 16.81 points, and those of group B were 26.86 ± 15.43 points (total score was 60 points), with statistical difference between these two groups. The three-stage strengthening mode based on ECG MOOC is an effective method to improve students’ ECG interpretation skills. Results show that an online and offline blended teaching strategy is superior to the traditional lecture method. Repeated practice is necessary for improving ECG interpretation competence. Students in the strengthening program group had better grades in the graduation examination.