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Ensuring the safety and stability of buildings during earthquakes is of utmost importance. This can be achieved by assessing the seismic performance of reinforced concrete structures with consideration of design details. This study focused on the seismic behavior of reinforced concrete buildings by comparing the effects of two different types of stirrups, namely those with a 135° angled end-hook shape and straight hooks, with variation of concrete strength. Pushover analysis of a sample building was performed to determine the effect of hook shape on stirrup reinforcement with a constant volumetric ratio for various concrete strength classes. The results of the analysis indicated significant differences in concrete strength and seismic behavior between the two stirrup configurations. The hooked stirrups demonstrated superior energy dissipation capability and ductility, which led to better seismic performance compared to unhooked stirrups across varying levels of concrete strength. To extend the investigation, the study compared the Mander et al., Kent–Scott–Park, and Kappos–Konstantinidis concrete models with different concrete classes (C50-C25-C20-C16-C10). The findings emphasized the importance of stirrup configuration in the design of earthquake-resistant structures. The study concluded that RC structural performance with the 135-degree hooked concrete members exhibited much better behavior of the 90-degree members for the various concrete strength. In this way, it has been revealed the arrangement and detailing of reinforcement in the construction beams and columns improves the governing effect on seismic structural performance. [ABSTRACT FROM AUTHOR]

The lateral confinement of stirrups can improve the load‐bearing capacity and ductility of reactive powder concrete (RPC) columns. To explore the compression behavior of RPC confined with high‐strength stirrups, 45 specimens were prepared and tested under axial compression. The concrete strength was in the range of 99.86–138.24 MPa, the tensile strength of stirrups was Grade 800, Grade 970, and Grade 1270, and the volumetric ratios of stirrups were in the range of 0.9%–2.0%. The results showed that the failure modes of RPC confined with stirrups were shear expansion failure. The compressive strength and ductility of confined RPC were improved with the increase of stirrups volumetric ratios, while stirrups strength slightly affected the compressive strength and ductility. In addition, the peak stress, peak strain, and residual stress prediction models were proposed. Furthermore, the ductility index prediction models were proposed, which can be applied to determine the volumetric ratio of stirrups in stirrups confined concrete columns. [ABSTRACT FROM AUTHOR]

The present paper proposes a mechanical model for the prediction of the response of slender reinforced concrete beams with corroded transverse and longitudinal reinforcements. The proposed model is based on the Modified Compression Field Theory and is able to predict the load–displacement curve of members subjected to monotonic displacement‐controlled tests up to their peak load. The corrosion‐damage effects are considered by means of an effective width of the beam and by means of reduced values of both cross‐sectional area and strain capacity of steel bars. The accuracy of the model is evaluated by comparison with results of tests reported in the literature. Moreover, a simple relation is suggested for the estimate of the shear strength of reinforced concrete beams with low values of the effective geometric percentage of (corroded) stirrups. [ABSTRACT FROM AUTHOR]

In this paper, four full-scale concrete columns with high-strength spiral stirrups (HSSS) are constructed and tested under low-cycle repeated loading. The specimens consisted of two castin-place columns and two precast concrete columns encased by a partly square steel pipe and bolt bars. The structural analysis of the HSSS columns of precast concrete conducted here is novel, and past experimental data for this are not available. To assess the seismic behavior and failure mechanisms of the new connections, quasi-static tests were carried out on columns prefabricated with them and cast-in-place specimens. The responses of all columns were compared, and the results showed that the failure modes of all columns are the large eccentric damage, and the destruction of all specimens occur at the column foot. The anti-seismic property of the precast HSSS concrete columns was comparable to that of the HSSS cast-in-place columns. A comparison of such performance parameters as energy dissipation and coefficient of ductility revealed that the precast HSSS concrete columns are suitable for use in earthquake zones. [ABSTRACT FROM AUTHOR]

With increasing the use of ultra-high performance fiber reinforced concrete (UHPFRC) in recent years, torsional design of UHPFRC beams has become of great importance. This paper presents an experimental and numerical study to investigate the torsional behavior of UHPFRC shallow and deep beams with fcu equal to 190.2 MPa. Ten UHPFRC beams with steel fibers volume fraction of 1.5% subjected to pure torsion were investigated. The provided torsional web reinforcement ratio, the area of longitudinal bars and the tested span to total height ratio (L/h = 6.0, 4.0, 2.0 and 1.0) were the studied parameters. A numerical model has been proposed to predict the torsional response of tested beams. Experimental results showed that increasing stirrups' spacing for the beams of the same L/h ratio (to be 235% of the maximum given by ACI 318-2019 code), reduced the experimental ultimate torsional strength by only 6.7%. The torsional web reinforcement ratio of UHPFRC shallow and deep beams can be safely taken to be 40% of the minimum required by ACI 318-2019. The maximum stirrups spacing can be safely taken the lesser of twice the beam width or 300 mm. The equation used by ACI 318-2019 and ECP-203-2020 for calculating the cracking strength in torsion has been modified to be suitable for UHPFRC beams by taking into consideration the L/h ratio and steel fibers percent. The proposed 3-D numerical model showed good predictions for the torsional strength of tested UHPFRC shallow and deep beams. [ABSTRACT FROM AUTHOR]

Push-off samples are simulated using nonlinear finite element analysis (NLFEA) to evaluate the effects of increased temperatures on the interface shear strength. Firstly, a control shear-key model is created, calibrated, and confirmed against independently published experimental data. Twenty-four NLFEA models are then created with different variables, including temperature (23°C (Room Temperature), 250°C (Raised temperature), 500°C, and 750°C and the number of steel stirrups (none, 1, 2, 3, 4, and 5). The NLFEA results demonstrate that the decreased fracture opening and slide in the damaged shear keys compared to the intact control sample represent the amazing effect of the number of steel stirrups. In addition, it has been revealed that the longitudinal shear force and slide, mode of failure, rigidity, and toughness are all significantly impacted by the degree of heat damage. In particular, a simplified approach is proposed for calculating the shear strength of push-off samples subjected to higher temperatures. [ABSTRACT FROM AUTHOR]

The corrosion of longitudinal rebar and stirrups will cause serious degradation to the bond performance between steel bars and concrete. To investigate the impact of both longitudinal rebar and stirrup corrosion on the bond behavior, 35 reinforced concrete (RC) pull-out specimens were subjected to accelerated corrosion tests of electroosmosis-constant current-dry wet cycles and pull-out tests, and then the influence laws of the degree of corrosion of the longitudinal reinforcement, degree of corrosion of the stirrups, cover thickness, stirrup spacing and longitudinal reinforcement diameter on the bond performance were studied. The bond behavior between corroded steel bars and concrete was analyzed from the aspects of corrosion form, failure mode and bond strength. Subsequently, based on the experimental data, a modified bond-slip constitutive model that considers the design parameters, stirrup corrosion and longitudinal rebar corrosion was built and verified. Finally, based on the established modified bond-slip constitutive model, the corroded RC column was simulated, and the accuracy of the established modified bond-slip constitutive model was verified at the component level. [ABSTRACT FROM AUTHOR]

Due to the strength reduction at the bent corners of fiber-reinforced polymer (FRP) stirrups, the high tensile strength of FRP reinforcement cannot be fully utilized in concrete structures. Although numerous experimental investigations have been conducted to study the reduced bent-corner strength, the mechanism of the strength reduction at bent corners has not been fully understood. This paper presents numerical research into the bent-corner strength of FRP stirrups with rectangular cross sections. Refined finite-element models are established based on Hashin's failure criterion and their validities are verified against six groups of 18 FRP stirrup specimens. Analyses of stress concentration in the elastic range and damage accumulation afterward are conducted to explain the mechanism of strength reduction at the bent corners of FRP stirrups. Further parametric analyses are conducted to quantitatively evaluate the contributing factors to the bent-corner strength and an empirical prediction equation is proposed. This research shows that the bond, compressive stress from concrete, and FRP material anisotropy are the critical contributors to the tensile stress concentration in the elastic range at the bent corners, which accounts for 7%, 48%, and 45% of the tensile stress concentration, respectively. The parametric analyses show that better bonding at the bent corners could potentially result in lower strength; the concrete properties and FRP width have limited influence on the bent-corner strength; and the bent-corner strength has logarithmic relation with the bent radius and thickness ratio of (R/t). This work reveals the critical mechanism of strength reduction of FRP stirrups at bent corners in concrete structures and potentially provides the opportunity for more efficient material use of FRP reinforcement. [ABSTRACT FROM AUTHOR]

Precast concrete structure is a low-carbon building system that has been attracting extensive attention in recent decades. Beam–column joints are the weak links in precast concrete structures. Past studies showed that the five-spiral stirrups had excellent confinement effects and had the potential to enhance the seismic performance of concrete structures. This study proposed the reinforcement of precast concrete beam–column joints by using five-spiral stirrups and investigated their seismic performance. Considering the influences of the joint failure mode, joint type, construction method, and stirrup type, low-cycle loading tests were conducted on six full-scale precast concrete beam–column joint specimens. Various seismic behavior indicators, such as failure modes, hysteresis curves, skeleton curves, ductility, and energy dissipation, were obtained. The results indicated that the deformation capacity of the precast joints with five-spiral stirrups was comparable to that of cast-in-place joints. Under different failure design criteria, the seismic performance of the precast joints was superior to that of cast-in-place joints. Furthermore, the experimental capacities of the precast joints, using five-spiral stirrups, were higher than the calculated values according to the design code, demonstrating an adequate safety margin. This research contributes to the development of low-carbon and sustainable construction practices in the field of precast concrete structures. [ABSTRACT FROM AUTHOR]

The article discusses the use of advanced algorithms and artificial intelligence in improving engineering principles for reducing materials, carbon emissions, and energy footprint in the building industry. It critiques a specific article that develops an artificial neural network algorithm for predicting the shear capacity of reinforced concrete deep beams without stirrups. The critique argues that the research object's choice is inconsistent with design standards and that the algorithm's results are irrelevant to engineering practice. It concludes by cautioning that while artificial neural network algorithms can be helpful, they should only be used to verify existing design methodologies or improve structural performance. [Extracted from the article]

This study investigates the effect of using recycled steel fibers (RSFs) extracted from cut tires with dimensions of 0.8 and 40 mm in diameter and length, respectively. Different percentages of fibers were used, which are 0.5, 1, 1.5, and 2%. Ten beams with dimensions of 150 mm × 240 mm and a length of 1,700 mm were tested, two of which are control beams without stirrups and using stirrups at a distance higher than the upper limit (d/2), which is a distance of 250 mm. In the case of using steel fibers without a stirrup, it is noticed that shear resistance increases gradually, but the type of failure remains shear. When using a minimum stirrup with steel fibers, the shear resistance increased significantly by 11.1, 23.7, 33.3, and 41.4%, respectively, compared to the reference beam without steel fibers so that the increased shear capacity in the presence of the minimum stirrups and optimal ratio of steel fibers of 2% reaches 122%, compared to the reference beam without stirrup and steel fibers, as well as converting the type of failure from shear failure to pure bending failure. When using a stirrup, this effect will be greater. The presence of RSF reduces deflection at cracking load, while increasing deflection at the ultimate load. Therefore, the stiffness and ductility ratio increased with the presence of steel fibers by 41.5 and 50.3%, respectively. Also, steel fibers delayed the appearance of beam cracks and reduced their widths.

This paper aims to contribute to a more rational understanding of the shear strength behavior of steel fiber‐reinforced concrete beams without stirrups. For this purpose, an experimental program comprising eight slender beams varying the fiber content and type, tested in three‐point bending configuration with a complete monitoring of the displacement fields of the failure span, was carried out. A detailed analysis of the shape and kinematics of the critical crack, associated with the investigation of the shear transfer mechanisms during the test given by mechanical models available in the literature, was performed. The theoretical–experimental analyzes proved to be a promising approach for quantifying the contribution of each relevant parameter to the shear capacity, such as the fiber concrete residual tensile response. The study, therefore, presents a contribution toward a rational and comprehensive methodology for the shear design of concrete members. The influence of shape and kinematics of the critical crack on the shear response is also reported and a theoretical explanation is provided to justify the fact that beams with the same characteristics have different cracking patterns but similar shear strength. [ABSTRACT FROM AUTHOR]

Due to the lack of relevant research, the effect of the lateral confinement provided by stirrups and concrete cover on the bond behavior between glass fiber-reinforced polymer (GFRP) bars and concrete is ambiguous, resulting in the lack of a practical bond slip theory of GFRP bars. Therefore, it is impossible to accurately analyze the load response of GFRP-reinforced concrete (RC) structures from the stress level. In this paper, the local bond behavior of ribbed GFRP bars was systematically analyzed by the beam-end tests. The test parameters include concrete strength, stirrup spacing, and concrete cover. In addition, a bond stress-slip model considering the bonding mechanism was proposed on the basis of the beam-end tests and previous research. The results show that, the development of concrete cracks is restricted due to the existence of stirrups, and the specimens tend to fail in pull-out failure with strong confinement of stirrups. With the increase in the lateral confinement level, the failure mode of specimens transits gradually and smoothly from splitting failure to pull-out failure. Meanwhile, the peak slip of specimens with splitting failure also increases, and its maximum value does not exceed the peak slip of the corresponding specimens with pull-out failure. The confining capacity of stirrups and concrete cover was unified by a proposed parameter K. Then, a bond stress-slip model based on parameter K was established to predict the bond behavior of ribbed GFRP bars. [ABSTRACT FROM AUTHOR]

This paper proposes a novel learning algorithm, the transfer ensemble neural network (TENN) model, to increase the performance of shear capacity predictions on small datasets, illuminating the usefulness of advanced machine learning techniques in general. By incorporating ensemble learning and transfer learning, the TENN model is designed to control the high variability inherent in machine learning models trained on small amounts of data. The novel TENN model is validated to predict the shear capacity of deep reinforced concrete (RC) beams without stirrups across varying data availability levels. Knowledge acquired through pretraining a model on slender RC beams is utilized for training a model to better predict the shear capacity of deep RC beams without stirrups. To evaluate the performance of the TENN model, three baseline models are developed and examined across multiple data availability levels. The novel TENN model outperforms the baseline models, particularly when trained on a very limited dataset. Furthermore, the proposed algorithm achieves a higher accuracy than the currently accepted design standards in accurately predicting deep RC beams' shear capacity and demonstrates the capabilities of the TENN model to extrapolate in other domains where large‐scale or physical testing is cost‐prohibitive. [ABSTRACT FROM AUTHOR]

This research presents the study of the behavior of reinforced concrete beams with hybrid nodes based on a 2³ factorial experiment design, whose independent variables are: shear moment ratio (M/V), ratio between the height of the node and the depth total of the reinforced concrete beam (hc/h) and the use of suspension stirrups. A test of eight types of specimens was performed with one replicate, for a total of sixteen specimens, plus four control specimens without knots. The tests show that the region disturbed by the joint should not be used for the bending theory of beams. The disturbance generates a decrease in the sectional resistance, which can be compensated with the suspension stirrups, which help to control cracking and transfer the efforts from the tension zone to the compression zone, with a significant increase in resistance. [ABSTRACT FROM AUTHOR]

Over the past few decades, numerous studies have explored the use of steel fiber (SF) as an alternative to transverse reinforcement rebars in reinforced concrete beams, either partially or completely replacing them. However, there are limited studies that have investigated the effect of fiber dosage and length on reinforced concrete beam performance under torsional loads without the use of transverse reinforcement rebars. In this study, experimental investigations were conducted to examine the performance of reinforced SF concrete beams subjected to torsional load, utilizing SFs as a complete substitution of transverse reinforcement rebars. Ten different concrete mixes with varying dosages of SFs, namely 0%, 0.5%, 1.0%, and 1.5%, were examined while maintaining the same aspect ratio for fiber length and diameter. The results revealed that the addition of SFs in the concrete mix had an impact on its properties, reducing workability but increasing flexural, tensile, and compressive strengths. By incorporating 1.0% of SFs in the concrete mix, the missing torsional strength resulting from the absence of stirrups was adequately compensated. Moreover, the presence of SFs significantly influenced the ductile behavior beyond the point of cracking in the tested beams. Hence, it is recommended that SFs are incorporated with dosages of 1.0% and 1.5% in the concrete mixture, particularly for beams subjected to torsion, as a viable substitute for stirrups. [ABSTRACT FROM AUTHOR]

To study the performance of UHPFRC continuous deep beams with openings, experimental and numerical investigations have been carried out. The test program included seven continuous deep beams with openings, in addition to one similar solid beam. The variables were the ratio of transverse reinforcement and the position, height, and width of the opening. The results showed that the failure mode of UHPFRC two-span continuous deep beams depends mainly on the position and size of the opening in the shear span. The shear failure occurs in the diagonal strut between the support and the applied force through the opening edges. The maximum spacing between stirrups (sv,max) of ACI 318-2019 was not suitable for UHPFRC. Providing stirrups with spacing 129% greater than sv,max of ACI 318-2019 had a slight effect on the failure load. Web openings of 20% of beam height reduced the failure load by 31.6% to 43.0% compared with a similar solid beam. For specimens with the same opening height and position, increasing the width of the opening by about 75% more than that of a similar beam reduced the failure load by about 27.8%. The proposed 3-D numerical model successfully predicted the failure load and performance of UHPFRC continuous deep beams. [ABSTRACT FROM AUTHOR]

The dynamic behavior of laced reinforced concrete (LRC) T‐beams could give high‐energy absorption capabilities without significantly affecting the cost, which was offered through a combination of high strength and ductile response. In this paper, LRC T‐beams, composed of inclined continuous reinforcement on each side of the beam, were investigated to maintain high deformations as predicted in blast resistance. The beams were tested under four‐point loading to create pure bending zones and obtain the ultimate flexural capacities. Transverse reinforcement using lacing reinforcement and conventional vertical stirrups were compared in terms of deformation, strain, and toughness changes of the tested beams. The inclination angles of the used lacing reinforcement with respect to the longitudinal reinforcement were 45° and 60°. The lacing reinforcement was efficient and participated actively in resisting the bending moments and shear forces at the same time. For the same diameter of lacing reinforcement, the 60° inclination angle imposed more ductility before failure than beams with lacing reinforcement of a 45° inclination angle. Moreover, the lacing bar diameter was more effective in improving the load‐carrying capacities when using the inclination angle of 45°. A finite element (FE) model was developed and validated using the experimental results based on the measured deformations and strains to conduct a parametric study. The investigated parameters included the effect of the arrangements of the applied loads, laced rebar diameter, inclination angle, tension reinforcement ratio, and concrete strength. [ABSTRACT FROM AUTHOR]

The author for the first-time summarizes information on finds of horse accessories in the burial grounds of the Vetluga and Vyatka interfluve of the X–XI centuries, provides a complete description of the categories of finds: stirrups (16 specimens), bits (10 specimens), buckles (3 specimens), bridle (3 specimens). The materials are systematized using the typology developed by A.N. Kirpichnikov on Ancient Russia. An attempt was made to reconstruct the bridle from the sanctuary assemblage 65 of the Dubovoe burial ground. Horse accessories from the burial grounds of the Vetluga and Vyatka interfluve have numerous analogies in the nomadic cultures of the Lower Volga, the Southern Urals, the Irtysh regions, the Altai and Eastern European steppes. A comparative analysis of findings from medieval Mari burial grounds and ethnographic sources on the traditional culture of the Mari and neighboring Finno-Ugric and Turkic peoples made it possible to understand certain features of the burial rite related to the sacred symbol of the horse.

An experimental investigation studied performance of reinforced concrete (RC) corner beam-column connection (BCC) subjected to cyclic loading. Each BCC consisted of upper, lower column and two beams; one of them was free end (A) while the other was fixed end (B). The cyclic loading was applied on the end of beam (A) while the beam (B) was unloaded and subjected to torsion stresses due to fixation. Two variables were investigated. The first is the eccentricity of the beam about column edge while the second is the effect of stirrup joint configuration on reinforced concrete beam column connection under cyclic loading. All BCCs were tested under reversible 14 cycles. The vertical displacement at the free end of beam (A), horizontal sway at mid height of the column, crack and ultimate loads were observed in details at each cycle. The results showed that the increase of stirrup length in the joint decreased the deflection at the same level of the load. The ultimate load of specimen, which was shifted by 25 mm, was less than the ultimate load of specimen, without shift, by 24%. When the joint stirrup was extended outside the column core by 50 mm in specimen Sp2, the capacity of the connection increased.

The concrete columns confined by high-strength stirrups exhibited higher bearing capacity and better deformation ability. Based on the test results of concrete columns confined by high-strength stirrups under lateral cyclic loading, it is found that stirrup yield strength could not be used directly in calculating bearing capacity, because the high-strength stirrup could not yield at the peak point. Moreover, according to the seismic performance of a total of 49 sets of confined concrete columns from this paper and other 5 research papers, an easy-to-use model of skeleton curve is proposed by using a set of empirical equations to calculate the characteristic points of skeleton curve. Furthermore, based on the proposed model of skeleton curve, hysteretic rules are developed for the unloading and reloading stages by providing calculating formula of unloading stiffness and ignoring the effect of strength degradation. Finally, the proposed model of skeleton curve and hysteretic rules are verified and evaluated by comparing the calculated curves and experimental curves. [ABSTRACT FROM AUTHOR]

This paper investigates the shear performance of corroded reinforced concrete (RC) beams with different stirrup corrosion rates and strengthening interventions. In this work, eight corroded beams strengthened with various interventions, including U‐shaped stirrup, bonded steel plate, and anchored steel plate strengthening techniques, were tested under static loading. The experimental shear capacity, load–deflection response, and failure modes of the unstrengthened and strengthened specimens were carefully studied. Three shear capacity models based on GB50010‐2010, ACI 318‐08, and Eurocode 2 codes were proposed and discussed. The results showed that all specimens have the same failure mode, that is, the shear–compression failure. The shear capacities are improved by 17.36%–23.61% and 23.76%–38.46% by these interventions for the specimens with 10% and 20% stirrup corrosion rates, respectively. The anchored steel plate technique provides the maximum improvement in the shear capacity. Additionally, the increased stiffness of corroded specimens with strengthening interventions is apparent when the corrosion rate is 10% but not obvious when the corrosion rate is 20%. The models based on GB50010‐2010 and ACI 318‐08 codes were proved to have higher accuracy but may overestimate the shear capacity. In contrast, the Eurocode 2‐based model comes with relatively low prediction accuracy but conservative results, and it is recommended for engineering design. [ABSTRACT FROM AUTHOR]

Reinforced concrete (RC) beam‐column joints often present brittle shear failure in the core area. The objective of the study is to study the effects of stirrup ratio and axial load ratio on the shear capacity of geometrically similar beam‐column joints having different structural sizes. In this work, a series of 3D mesoscale simulations on the shear failure of RC beam‐column joints were conducted and validated, in which the concrete heterogeneity was considered explicitly. The simulation results indicate that stirrups can improve the shear strength of joints, enhance the ductility, improve deformation ability, while weaken the size effect on the nominal shear strength. Moreover, the increasing axial load ratio would lead to the increase of shear strength, as well as the increase of size effect. Based on the modeling results, a novel semiempirical and semitheoretical size effect law considering the quantitative effect of stirrups and axial load ratio was proposed. In addition, the proposed size effect law was verified against with some available test data. [ABSTRACT FROM AUTHOR]

Prestressed concrete (PC) sleepers are used in modern railway systems worldwide. Although the PC sleepers are durable under harsh environmental conditions, frequent cracks can be found hindering the railway's capacities. This article investigates an improvement of placing steel stirrups in shear deficient PC sleepers commonly used in railways of Thailand. PC sleepers with a cross‐section of 258 × 205 mm2 varied with five different stirrup's ratios were tested under a three‐pointed bending load to observe the improvement of shear resistance. From the experimental results, the peak load of PC sleepers with stirrups can be enhanced from 14.1% to 21.2%, whilst the failure deformation can also be enhanced from 87.5% to 176.6%, compared with PC sleeper without any stirrup. With increasing stirrup's ratio, failure modes of PC sleepers were shifted from brittle shear to ductile flexural failures. Moreover, the PC sleepers with deformed‐bar stirrups exhibited better bond interfaces than that with rounded‐bar. Then, the proper stirrup's ratio and type of steel stirrups are recommended to enhance the shear resistance of the PC sleeper. In addition, a finite element analysis results based on advanced constitutive models and the fixed‐cracking approach showed good agreement with the results from experiment. [ABSTRACT FROM AUTHOR]

The performance of open stirrups shear reinforcement not fully anchored is investigated, with a type of detail that has been used in construction sites as a support for the top flexural reinforcement to guarantee the right height position; and subsequently, it has also been used to address punching. Five internal slab–column connections subjected to symmetrical loading were tested, including a reference connection and four connections with anchorage variation of shear reinforcement, and their performance was compared with estimations by Codes and Standards and with test results from other authors. Even though the tests presented showed that an increase from 25% to 45% in the punching resistance can be achieved, and that the deformation capacity can also be improved, more tests with other detailing, ratios of flexural and shear reinforcement, and so on, are needed before it can be recommended as an effective shear reinforcement alternative. [ABSTRACT FROM AUTHOR]

Very few studies have been dedicated to the size effect on the shear behaviour of reinforced concrete (RC) columns. In particular, there lacks a design equation that can quantitatively represent the effect of related parameters on the size effect on nominal shear strength for RC columns. This work presents a mesoscale numerical analysis of the mechanical response of geometrically similar RC columns subjected to constant axial load and monotonic lateral load. In the numerical model, the inherent heterogeneous nature of concrete and steel/concrete interaction were considered. The numerical model was validated against test results in the literature, and then adopted to conduct a parametric study of the shear behaviour and size effect of RC columns. The investigated parameters involved the shear–span ratio, stirrup ratio and axial load ratio. The results indicated that the nominal shear strength presents an obvious size effect. This size effect on nominal shear strength was gradually weakened as the stirrup ratio and shear–span ratio increased. Moreover, considering the quantitative influence of stirrup ratio and shear–span ratio on size effect, a modified equation was derived to predict the shear resistance of RC columns. Through comparing with available experimental results, the modified equation was demonstrated to be accurate and reliable. [ABSTRACT FROM AUTHOR]

The incorporation of steel fibers improves the microscopic ductility of ultrahigh-performance concrete (UHPC) materials, and their macroscopic ductility can also be improved by the restraining effect of composite stirrups. Two defects can be found in the stress--strain model of UHPC restrained by stirrups based on the design-oriented method: the restraint coefficient of the stirrup is the effective restraint coefficient at the peak state of the specimen, while the variation in the restraint stress of the stirrup with the axial--hoop strain relationship (strain path) is ignored. In this study, a strain-pathdependent stress--strain model for UHPC constrained by stirrups and fibers is proposed through a database with 10 sets of test results on UHPC columns, which alleviates the shortcomings of the design-oriented model. (1) On the basis of the axial--hoop strain relationship curve in the test results, an axial--hoop strain model of UHPC restrained by stirrups is established. (2) The variation in the restraint stress of the stirrup with strain path is considered. (3) On the basis of the stress--strain model of actively constrained concrete, an iterative method of subsections is adopted, and a UHPC stress--strain model restrained by stirrup based on strain path is established. Results show that the established axial--hoop strain equation can better predict the hoop strain of UHPC restrained by stirrups and steel fibers, the calculated value of peak stress of UHPC constrained by stirrups based on strain path is in good agreement with the test results, and the outcomes of the path-dependent stress--strain model are in better agreement with the experimental results than those of the designoriented stress--strain model. [ABSTRACT FROM AUTHOR]

Pultruded Glass Fiber-Reinforced Polymer (pultruded GFRP) composite produced by the pultrusion method has become popular in civil engineering applications due to its lightness, corrosion resistance and high strength. However, the use of the pultruded profile combining with reinforced concrete is still limited due to a lack of knowledge. Therefore, the behavior of the pultruded GFRP profile infilled with reinforced concrete beams (hybrid beams) is investigated. This study focused on the effects of stirrup spacing for the hybrid beams. Pursuant to this goal, a total of eight different beams were tested under four-point loading. One reference beam without the pultruded profile and seven hybrid beams having different stirrup spacings were considered. Moreover, the hybrid beams with and without stirrups were wrapped by unidirectional GFRP composite to investigate the effects of stirrup spacing on shear capacity of the beams strengthened by GFRP composite. The experimental findings revealed that tightening stirrups increased the load and energy dissipation capacities of the hybrid beams; however, it could not prevent brittle failure. On the other hand, wrapping hybrid beams with GFRP composite increased the load and energy dissipation capacities and also prevented brittle failure regardless of the presence of the stirrups. Therefore, it is strongly recommended that the unidirectional pultruded profiles should be strengthened with 90° GFRP wrapping to have ductile behavior. [ABSTRACT FROM AUTHOR]

This paper presents the theoretical behaviors of concrete beams with and without stirrups under drop weight testing. The main objective of this work is to investigate numerically the influence of different types of longitudinal steel reinforcement (steel bars and FRP bars) on the impact behavior of concrete beams in terms of peak load, and deflection. In addition, the effect of drop height, the presence of stirrups, the concrete compressive strength of the concrete beams, and strengthening concrete beams by FRP strips have been involved in investigating their contribution to the behavior of the impact response. The analytical work has been carried out using ABAQUS/CAE 2019. Firstly, the model has been validated against four beams tested experimentally with various impact heights. Then, four groups of beams with different parameters have been simulated and tested under the same impact loading conditions. The first group has consisted of four beams with normal concrete strength reinforced by FRP bars. The second group has been strengthened externally by CFRP strips. The third and the fourth groups are with stirrups and higher grade of concrete, respectively. It has been found out that the current simulation could be an effective tool for predicting the dynamic performance of beams with and without stirrups subjected to impact loading. Furthermore, the improvements done to the available experimental specimens have led to increase the peak impact load and decrease the ultimate deflection. [ABSTRACT FROM AUTHOR]

This paper presents the behavior of glass fiber-reinforced polymer (GFRP)-reinforced ultra-high-performance concrete (UHPC) beams without shear stirrups. An experimental program is conducted to examine the implications of variable geometric, loading, and reinforcement configurations, particularly for the effective depth-to-height ratio (0.75 ≤ d/h ≤ 0.90), shear spandepth ratio (1.18 ≤ a/d ≤ 3.23), and GFRP reinforcement ratio (1.35% ≤ ρf ≤ 4.85%) of the beams. Also tested are UHPC cylinders and prisms under axial compression and three-point bending. The strength development of UHPC is remarkable during the first 3 days of casting, after which a gradual and asymptotic growth rate is associated because of saturated pores and the limited attractions of calcium-silicate-hydrate networks. Compared with the factors related to the placement of the GFRP reinforcing bars (d/h and ρf), the a/d is more influential in controlling the capacity and the postpeak deformation of the beams by altering load-transfer mechanisms. The stress of a shear-compression zone is redistributed under arch action and results in supplementary cracks along the beam span. The horizontal splitting of UHPC at the reinforcing bar level caused by the dowel action of GFRP is dependent upon the reinforcement ratio. Analytical models are formulated, and design guidelines are recommended. [ABSTRACT FROM AUTHOR]

It became common practice to utilize near-surface mounted (NSM) bars to improve the shear capacity of steel-reinforced concrete (RC) beams. Consequently, carbon fiber-reinforced polymer (FRP) is usually used to improve RC beams' shear performance. Conversely, the use of Glass FRP (GFRP) for enhancing the shear behavior of the steel-RC and GFRP-RC beams is still limited. This study used NSM GFRP or steel bars to strengthen RC beams reinforced in tension with steel or GFRP bars. In addition, a new NSM technique was conducted using high-strength concrete (HSC) layers reinforced with GFRP or steel bars bonded within grooves to enhance beams' shear capacity. The results of seventeen beams used in the tests showed that NSM HSC layers improved the shear performance of RC beams more than NSM bars. Also, the beams reinforced in tension with steel bars had higher shear efficiency and were stiffer than those reinforced with GFRP bars. Conversely, the shear efficiency of steel RC beams strengthened in shear with internal stirrups or NSM reinforcement (or both) increased by 142.8–211.7% compared to GFRP RC beams without internal and NSM shear reinforcement. Conversely, the shear capacity of the steel-RC beams strengthened in shear with internal stirrups or NSM reinforcement (or both) increased by 153.5–279.9% compared to the corresponding beam without GFRP RC beam without internal and NSM shear reinforcement. The numerical analysis using the ABAQUS program showed great effects of the tension reinforcement and the NSM materials on the strain of longitudinal bars, stirrups and NSM reinforcement.

Prediction of propagation time of corrosion is a key element in evaluating the service life of corroded reinforced concrete (RC) structures. Corroded steel products often expand in volume and thus generate tensile stress in the concrete cover. When this tensile stress exceeds the tensile strength of the concrete, cracking occurs. The tensile stresses in concrete due to corrosion are usually perpendicular to the longitudinal axis of the reinforcement. In the reinforced concrete beams, tensile stresses in concrete due to bending is perpendicular to the longitudinal direction of stirrups. In the reinforced concrete slabs, the tensile stresses in concrete due to bending is also perpendicular to the axis of longitudinal reinforcement subjected to bending in the other direction. In such cases, the tensile stresses in concrete due to corrosion of reinforcement has the same direction as the tensile stress caused by bending. When the load-induced stress in the concrete has the same direction as that of the corrosion-induced stress, cracks will likely appear more quickly and vice versa. The main objective of this paper is to build a predictive model of corrosion propagation time taking into account: (1) the effect of stresses due to load; (2) the change of corrosion current density. The model was implemented on Matlab software. The results show the influence of the load, and other parameters on the corrosion propagation stage, when considering the end of this corrosion propagation stage is cracking of concrete cover.

To research the deterioration of the mechanical properties of stirrup-corroded concrete columns under the effect of load and chloride, accelerated corrosion and load carrying capacity tests were carried out on concrete columns subjected to long-term axial loading by means of dry and wet cycles with extra electric currents. The test results showed that under the effect of axial load and chloride, the corrosion-induced cracks of stirrup-corroded concrete columns mainly developed along the direction of the longitudinal reinforcing steel bars (cracks along longitudinal reinforcing steel bars caused by corrosion) and there were almost no corrosion-induced cracks along the direction of the corroded stirrups. The length and maximum width of the corrosion-induced cracks increased with the stirrup corrosion rate, but the average width of the corrosion-induced cracks did not change significantly. After the stirrup-corroded column reached the ultimate load, the concrete cover spalled off in pieces along the corrosion-induced cracks and loading cracks, the core concrete was crushed, and the test column produced obvious brittle failure. With the increase in the corrosion rate of stirrups, the stiffness and ultimate bearing capacity of the column decreased. Considering factors such as damage to the column section caused by stirrup corrosion, the decrease in the lateral restraint effect of the corroded stirrup on the longitudinal reinforcing steel bars, and buckling of the longitudinal reinforcing steel bars, the ultimate bearing capacity prediction model of the short column subjected to axial compression due to stirrup corrosion was established. The calculated values of the model were in good agreement with the measured values, indicating the model has good applicability. [ABSTRACT FROM AUTHOR]

This study investigated the shear resistance and damage evolution of glass fiber-reinforced polymer (GFRP)-reinforced concrete short columns. Five circular concrete short columns reinforced with GFRP bars and spiral stirrups were fabricated and tested under lateral thrust in the laboratory. The test variables involved the stirrup reinforcement ratio, the longitudinal reinforcement ratio and the type of stirrups. The failure modes, load-displacement curves, strain responses and crack characteristics of these columns were documented and discussed. The accuracy of shear design equations in predicting shear capacity of such columns was evaluated. In addition, the digital image correlation (DIC) instrument was used to identify the full-field strain and damage zones of circular concrete short columns. Several smart aggregate (SA) transducers coupled to the surface of these columns were used to monitor its damage status. The energy ratio index (ERI) and the damage index based on smart aggregate were established to characterize damage level of such columns. The test results indicate that the shear capacity is improved 5.6% and 31.1% and the lateral ultimate displacement is increased 67.7% and 400% as the stirrup reinforcement ratio of the concrete short column is increased from 0 to 0.19% and 0.47%, respectively. The shear capacity equation proposed by Ali and his co-workers, considering a strain limit of 0.004 E f v , gives accurate predictions of the shear capacity of circular concrete short columns reinforced with GFRP bars and spiral stirrups. The variation in ERI values is explained by the development of damage zones of the column obtained with DIC technology and with the proposed damage index based on the smart aggregate it is feasible to evaluate the damage level of circular short concrete columns. [ABSTRACT FROM AUTHOR]

Due to the intrinsic complexity, there has been no widely accepted mechanics-based estimation model of the shear performance of Fiber-Reinforced Polymer (FRP)-reinforced concrete beams. Capitalizing on a large amount of previous experimental data, data-driven machine learning (ML) models could be potentially suitable for addressing this problem. In this paper, four existing shear design provisions are reviewed and four typical ML models are analyzed. The accuracy of codified methods and ML models are compared and analyzed based on our established extensive database of FRP-reinforced concrete beams with rectangular cross sections. A series of artificially selected features considering the shear-carrying mechanisms of FRP-reinforced beams are incorporated into the proposed ML models to show their influence on the model validity. Bayesian optimization is utilized to automatically tune the hyperparameters of different ML models. Compared to the most satisfying codified predictions from CSA S806, the best ML model, XGBoost, can provide more accurate and consistent predictions for the database, with R2 enhanced by 15% and the MAE and RMSE reduced by 59% and 52%, respectively. With the selected features based on domain knowledge, the performance of ML models is further enhanced, shown by the most important features being the added ones. With outstanding performance on a large database and singular test, the ML approaches have great potential in guiding the shear design of FRP-reinforced concrete. [ABSTRACT FROM AUTHOR]

This research investigated continuous rectangular spiral shear reinforcement as transverse reinforcement under pure torsion and compared it with conventional concrete beams. This present study tested three different continuous rectangular spiral stirrup (80°, 75°, and 45°) and one with traditional type stirrup (90°). M30 grade concrete and Fe 415 steel were used. The Test results indicate that the maximum ultimate torque at 75° is 32 kNm. Also, the maximum percentage increase in ductility is 19%. The maximum stiffness was observed at 80° stirrups is 2104 kN.m/radians. [ABSTRACT FROM AUTHOR]

Transverse shear reinforcement is usually used to resist the induced shear stresses in conventional concrete beams. Ultra-high performance concrete (UHPC) with fibres has high strength, post-peak strength, and strain softening. Such features can impact the behavior of the beam under loading. This paper presents the results of experimental tests performed on simply supported UHPC T-beams with basalt or steel fibres, with or without stirrups, subjected to four-point bending loads. The volume fraction of basalt fibres, the shear span, and the presence of stirrups are adopted as parameters. The possibility of achieving equivalent performance by using basalt or steel fibres, as shear micro-reinforcement, instead of using traditional steel stirrups is discussed from viewpoint of the beam structural behavior due to shear stress. The results show that the shear resistance increases with increasing fibre content and decreases with increasing shear span. The addition of basalt or steel fibres alters the fracture from brittle to ductile. Also, it is possible to partially replace the stirrups by using 1.0 % or more steel fibres or 0.5-1.0 % basalt fibres in the UHPC matrix. However, it is preferable to use a considerable ratio of shear rebars to avoid the dominance of shear failure. [ABSTRACT FROM AUTHOR]

The steel fiber-reinforced polymer composite bars Known as (SFCB) are new kind of reinforcement, for concrete structures. A layer of glass fibers and reinforced polymer surrounding the steel bars resulting in the (GFRP), when used as concrete reinforcement contributes for enough, serviceability strength, and durability. Increasing the elastic modulus of GFRP bar, which have function of protecting corrosion in addition to reduce the initial cost of the FRP bar, is the purpose of hybridization. SFCB has the advantages of being noncorrosive, nonmagnetic nonconductive, and light in weight, along with high strength. This study presents the behavioral characteristics of RC beams, with tensile lap-spliced steel fibers—coated bars under flexure. Ten beam specimens were tested, with concrete cross-section of (25*40*420) cm and compressive strength of 30 MPa. One beam specimen, (R) was taken as reference as it was reinforced with no lap splice. Nine beam specimens were divided into three groups. Group (A) contained three beam specimens reinforced with SFCB of diameter 16 mm and lap splice of 50φ, one with stirrups, without stirrups and with staggered lap splice. Group(B) contains three beams reinforced with SFCB of 16 mm diameter and lap splice of 55 φ one with stirrups, without stirrups and with staggered lap splice. Group(C) contains three beam specimens reinforced with SFCB of 16 mm diameter and lap splice of 60 φ one with stirrups, without stirrups and with staggered lap splice. Beams were exposed to pure flexure. Crack patterns and results are presented along with stress-strain curves. Finally, conclusions are summarized and presented. [ABSTRACT FROM AUTHOR]

The CRB600H reinforcement is a new type of cold-rolled ribbed steel bar, which has the advantages of green and low carbon, stable quality, saving precious metal resources and so on. In order to study the axial compression performance of short concrete columns with CRB600H stirrups, the finite element analysis model of high-strength reinforced concrete stub columns was established by using ABAQUS, and the accuracy of the finite element model was verified by literature experiments. The effects of stirrup construction (Type A, B and C), stirrup spacing and concrete strength on the axial compressive bearing capacity and ductility of concrete columns with CRB600H stirrups were analyzed and compared with HRB400 stirrups columns. The results showed that the peak bearing capacity of the specimens with CRB600H stirrups was similar to that with HRB400 stirrups, and the ductility of the specimens was improved with CRB600H stirrup. Compared with the type A stirrup and type C stirrup, the type B stirrup had the best concrete restraining effect, and the ductility and peak bearing capacity of the specimens were higher. With a decrease in the stirrup spacing, the ductility and peak bearing capacity of the specimens increased. With an increase in concrete strength, the peak bearing capacity increases, but the ductility decreases. Through parameter analysis, a formula for calculating the axial bearing capacity of 600 MPa high-strength stirrup concrete stub columns based on the effective confinement index (keλt) was proposed. It is suggested that the equivalent volume of a HRB400 stirrup can be replaced by a CRB600H stirrup in the actual project. At the same time, when the high-strength stirrup was used, the restraining effect of the stirrup on concrete should be considered in the calculation of the axial compression bearing capacity. [ABSTRACT FROM AUTHOR]

Copyright of Revista de Arquitectura (1657-0308) is the property of Universidad Catolica de Columbia, Facultad de Arquitectura and its content may not be copied or emailed to multiple sites or posted to a listserv without the copyright holder's express written permission. However, users may print, download, or email articles for individual use. This abstract may be abridged. No warranty is given about the accuracy of the copy. Users should refer to the original published version of the material for the full abstract. (Copyright applies to all Abstracts.)

Copyright of Tikrit Journal of Engineering Sciences is the property of Republic of Iraq Ministry of Higher Education & Scientific Research (MOHESR) and its content may not be copied or emailed to multiple sites or posted to a listserv without the copyright holder's express written permission. However, users may print, download, or email articles for individual use. This abstract may be abridged. No warranty is given about the accuracy of the copy. Users should refer to the original published version of the material for the full abstract. (Copyright applies to all Abstracts.)

Simple Summary: Preventing possible pain caused by functional asymmetry of both rider and horse needs an investigation of the rider-related variables that could affect the distribution of mass on the stirrups. Using digital load cells applied to the stirrup leathers of a wooden horseback model, we measured the directional force exerted by both legs of 147 riders on stirrup straps determining possible asymmetries. Furthermore, we investigated the possible associations between the asymmetry and eight variables related to the riders: gender, age, level of riding ability, years of riding experience, riding style, motivation of riding, primary discipline, and handedness. The preliminary findings confirmed that the majority of the riders are asymmetrical while riding on wooden horseback. Riding style seems to be a risk factor for asymmetry. Further studies using larger sample groups controlled for leg dominance and riding experience are required. Riders' asymmetry may cause back pain in both human and equine athletes. This pilot study aimed at documenting in a simple and quick way asymmetry in riders during a simulation of three different riding positions on wooden horseback using load cells applied on the stirrup leathers and identifying possible associations between riders' asymmetry and their gender, age, level of riding ability, years of riding experience, riding style, motivation of riding, primary discipline and handedness. After completing an interview to obtain the previously mentioned information, 147 riders performed a standardized test on a saddle fixed on a wooden horseback-shaped model. The riding simulation was split into three phases of 1 min each: (1) sit in the saddle, (2) standing in the stirrups and (3) rising trot. The directional force on the left and the right stirrup leathers was recorded every 0.2 s. A paired t-test was performed on the recorded data to test the difference (i.e., asymmetry) in each phase. In phases 1, 2 and 3, 99.3% (53.4% heavier on the right (R)), 98% (52.8% heavier on the left (L)) and 46.3% (51.5% heavier on the left (L)) of the riders were asymmetrical, respectively. Chi-square tests showed a significant association between riding ability and riding experience, but no significant association between reported handedness and calculated leg-sidedness (p > 0.05). Univariate logistic (1: asymmetry, 0: symmetry) regression analysis was performed only on the phase 3 data. One-hand riders were found twice more likely to be asymmetrical than two-hand riders (Odds Ratio (OR): 2.18, Confidence Interval (CI): 1.1–4.29; p = 0.024). This preliminary study confirmed that the majority of the riders are asymmetrical in load distribution on stirrups and suggested the riding style as a possible risk factor for asymmetry. [ABSTRACT FROM AUTHOR]

This paper aims to investigate the effect of using different configurations of near-surface mounted carbon-fiber-reinforced polymer (NSM-CFRP) strips on the shear strength of strengthened and rehabilitated reinforced concrete (RC) T-beams with different internal shear stirrup spacing. The internal shear stirrup spacing was 50 and 150 mm. The NSM-CFRP strips were at an inclination of 45° and spaced at 75 and 150 mm. A total of eight beams were tested in this study: two beams without NSM-CFRP as control beams for the purpose of comparison; three beams were strengthened by NSM-CFRP; and three beams were rehabilitated by NSM-CFRP. The experimental shear capacities were compared with the theoretical values predicted by the ACI 440.2R-17. The results indicated that the use of NSM-CFRP strips enhanced the shear capacity for all beams compared to their corresponding control beams. The enhancements in the shear capacity increased with the decrease in the spacing of the internal shear stirrups and NSM-CFRP strips. The ACI 440.2R-17 was conservative in predicting the theoretical shear capacities. [ABSTRACT FROM AUTHOR]

Through axial compression tests, the influence of three stirrup indexes (space, form, and strength) on the confining performance of multi-spiral composite stirrups in square reinforced concrete (RC) columns were analyzed, and the square RC columns with traditional well-shaped composite stirrups were used as the reference group. The results show that the multi-spiral composite stirrups had a positive contribution to the important indexes (bearing capacity and ductility) of the square RC columns due to its multiple restraint mechanism on core concrete. In terms of constraint effect, the five-spiral composite stirrup is the best, followed by the four-spiral composite stirrup, and the last is the traditional well-shaped composite stirrup. The section of the concrete square column is divided into highly constrained, partially constrained and unconstrained regions and the constraint mechanism of multi-spiral composite stirrups is discussed. The formulas for calculating the peak stress, peak strain, and ultimate compressive strain of the constrained column are presented, and the relative error between the theoretical values and the tested values is small. The constitutive model of concrete constrained by multi-spiral composite stirrups is established and compared with other constitutive models. The results show that the proposed model fits well with the experimental curves. [ABSTRACT FROM AUTHOR]

The most crucial components in the case of roofs with two levels or a variable floor height are variable depth beams. In order to investigate the flexural behavior of reinforced concrete (RC) beams with varying depths under static loads, experimental research was conducted. Under the four-point bending flexural test, two reference beams with constant depth, six dapped beams at the soffit, and four dapped beams at the top were tested. For all beams with a 150 mm depth, a 100 mm increase in depth occurred at the middle span of the beams. The primary characteristics included the impact of increasing depth, the impact of stirrups' absence and their various ratios, and the characteristics of the longitudinal bars at the locations of sudden depth changes in either the top or bottom bars. Both the cracks' progression and the load-deflection relationship along the beam's length were observed. The ultimate carrying load (Pu) was reduced by 23.56% and 27.35% as a result of the 100 mm increase in the half-span of the beam over the constant depth in case of changes at the top and soffit, respectively. The Pu was increased by a ratio ranging from 20.9% to 31.35% for the bottom dapped beams and by a ratio of 29.79% for the top dapped beams due to the various stirrup ratios in the dapped area. The ductility was significantly impacted by the elevated stirrup ratios in the dapped area. The predicted results and the experimental results matched when the Pu of the tested beams was evaluated using the strut and tie model. [ABSTRACT FROM AUTHOR]

Background. How the modification of saddle fitting parameters in horse riding affects rider's kinetics is very uncertain. The aim of this study is to describe how manipulating the two main adjustments that an end-user is likely to perform (saddle tilt and stirrup length) affects the biomechanics of a horse rider on a living horse. Methods. Eleven showjumpers volunteered to take part in this study. Each participant performed a 120-strides standardization trial at trot and canter, with 0° saddle tilt and stirrup length that would position the rider's knee at 90°. Following the standardization trial, four interventions were performed, which consisted of 60 strides with 60 mm shorter stirrups, 60 mm longer stirrups, 4° forward tilted saddle and 4° backward tilted saddle. Stirrup and rein tension forces were measured with tension loadcells. A symmetry index was calculated. Acceleration was measured with inertial measuring units at the helmet and back of the rider and shock attenuation was calculated. Results. Shortening the stirrups and adjusting saddle tilt significantly enhanced shock attenuation at canter and increased force on the stirrups at trot and canter (p<0:05). Lowering the stirrups reduced rein tension forces (p=0:01). At trot, adjusting saddle tilt and stirrup length enhanced symmetry index on the bit (p<0:05). These results allowed for general guidelines to be proposed, although individualization became an evident part of any saddle setup design due to a high inter-subject variability. [ABSTRACT FROM AUTHOR]