Eccentric Loading Research Articles

The research evaluates the influence of load eccentricity on square shallow foundation behavior when embedded in dry sandy soil at a relative density of soil =30% with and without skirts. Laboratory model tests analyzed a 10 × 10 cm foundation under one central load condition (E/B = 0, where E is the load eccentricity and B is the foundation width) and three eccentric load conditions (E/B = 0.04, 0.08, and 0.16). Three skirt lengths were examined: 0.5B, 1B, and 1.5B. The results showed that skirted foundations significantly enhanced bearing capacity and reduced settlement compared to unskirted ones. The maximum improvement in bearing capacity occurred under central loading with a skirt length of 1.5B, where the Bearing Capacity Ratio (BCR) reached 4.4 times. Under the highest eccentricity (E/B = 0.16), the BCR decreased to 3.95 times. Settlement was also effectively reduced, with the Settlement Reduction Factor (SRF) reaching 0.921 under central loading and remaining as high as 0.85 under eccentric loading. The results confirm that skirted foundations improve the bearing capacity and reduce settlement of shallow foundations on sandy soils under both central and eccentric loads.

Behavior of recycled brick aggregate concrete column retrofitting with carbon fiber reinforced polymer under concentric and eccentric loading

Failure analysis and damage characterization of steel fiber reinforced manufactured sand concrete column under eccentric loading

Predicting the ultimate strength of rectangular concrete-filled steel tube columns under eccentric loading using a knowledge-enhanced machine learning framework

Model Test Investigation of Eccentric Load Effect on a Gully Installed Circular Culvert

In this study, the effects of concrete compaction techniques and different cross-sectional shapes (square, rectangular, and circular) on load-carrying capacity are examined in relation to the structural behavior of concrete-filled steel tube (CFT) columns under axial loading. Because of their exceptional strength, ductility, and capacity to absorb energy, CFT columns are being used more and more in contemporary construction, especially in seismically active areas. A thorough literature review, experimental testing of CFT specimens using various concrete grades (M20, M30, and M40), and comparison of the findings with current design codes (AISC, ACI, and EC4) are all included in the study. The main conclusions show that compacted CFT columns can support loads much higher than their non-compacted counterparts, with circular sections outperforming square and rectangular ones. The study emphasizes how crucial concrete compaction is to improving the performance of CFT columns and offers suggestions for additional research, such as investigating the effects of eccentric loading and using finite element analysis to enhance structural modeling.

Suction embedded plate anchors are widely used in deepwater mooring systems, which can withstand significant vertical loading. During the installation, the mooring chain is tensioned and causes the anchor to rotate, which is known as keying. With a large deformation finite element approach of the coupled Eulerian–Lagrangian method, the chain effects are incorporated into the keying of suction embedded plate anchors. The effectiveness of the proposed method is verified by numerical results and centrifuge tests. The numerical study reveals that the installation angle of the chain has a significant effect on the loss of embedment, especially combined with the effects of load eccentricity and soil strength. The losses of embedment are 0.024~0.273 and 0.217~1.755 anchor width for the installation angles of 15° and 90°, respectively. The ultimate bearing capacity factor decreases with the increasing of load eccentricity and soil strength, because a cavity is formed at the anchor back. Empirical formulae are finally developed for engineers to rapidly estimate the embedment loss and ultimate pullout capacity of suction embedded plate anchors.

To investigate the compressive deformation mode and flexural mechanical performance of steel tube columns filled with aluminium foam, a series of corresponding experiments under the quasi-static eccentric compressive conditions were performed to obtain the failure deformation diagram, load-deflection curve and load-strain relationship. Based on the experimental study, A finite element model was established to analyze the mechanical performance of steel tube columns filled with aluminum foam under different loading eccentric distances. The results show that the restrained bending deformation was more pronounced in the steel tube column filled with aluminum foam, and this deformation significantly improved the overall mechanical performance as the porosity of the aluminum foam decreased. Compared with the pure steel column, the ultimate loads of the aluminium foam-filled steel tube column with porosities of 90%, 80% and 70% were increased by 87.13%, 93.41%, and 104.11%, respectively. The tensile or compressive strains of the pure steel tube column and that filled with aluminium foam respectively appeared symmetric and asymmetric phenomena because the failure deformation mode of the steel tube column was influenced by filling aluminium foam. Compared with axial compression, the ultimate vertical loads of the aluminium foam-filled steel tube column with loading eccentricities of 30 mm, 50 mm, 100 mm and 150 mm decreased by 48.78%, 60.35%, 80.19% and 88.61%. The steel tube columns filled with aluminium foam under axial compressive action and eccentric load appeared different failure modes, which were respectively the progressive crushing symmetrical deformation and bending deformation. The corresponding failure phenomena of these tubes were observed to transition from local buckling occurring at the loading or fixed end to overall bending deformation along the column length with the gradual increase of eccentricity. Furthermore, the bending moment value of the steel tube column filled with aluminium foam obtained from the experiment under different loading eccentric distances increases with the decrease of load eccentricity.

Hydrostatic bearings are extensively utilized in precision and ultra-precision machinery. Owing to the small oil film clearance of such bearings, they are prone to tilting under eccentric loads, which may ultimately lead to bearing failure. To investigate the eccentric load characteristics of hydrostatic bearings, a typical rectangular hydrostatic oil pad unit was selected as the research object. First, an analytical model for the eccentric load-carrying capacity of the rectangular oil pad was established. This model was then validated through computational fluid dynamics (CFD) simulations. On this basis, the static and dynamic characteristics of the rectangular hydrostatic oil pad were systematically studied. The results indicate that oil supply pressure, orifice diameter, and oil pad dimensions exert significant influences on the angular stiffness and angular damping of hydrostatic bearings. Specifically, increasing the oil supply pressure to above 3 MPa can facilitate the enhancement of anti-eccentric load capacity. Under the premise of ensuring static load-carrying capacity, a moderate increase in orifice diameter is conducive to improving anti-eccentric load capacity. When the oil pad area is fixed, adjusting the width-to-height ratio of the oil pad can modify the angular damping coefficient in the corresponding direction. However, the adjustment tends to reduce the angular damping coefficient in other directions, necessitating a comprehensive evaluation in practical applications.

The small dimensions of microfabricated devices present challenges in applications such as inertial sensing, where a larger proofmass is necessary for enhanced sensitivity. An effective approach to addressing the limitations of linear sensing is to use nonlinear mechanisms that adapt the device’s response according to different operating conditions. This paper introduces a new nonlinear spring mechanism for use in microsensors that harnesses the buckling phenomenon to achieve stiffness softening. The proposed mechanism utilizes a micro-arm to apply an eccentric axial load to an inclined beam, causing it to buckle in a controlled manner under a specified load. Once buckled, linear springs dominate the response of the system. We demonstrate that this method results in a smaller bias displacement compared to previously reported techniques based on snap-through behaviour, leading to potential reductions in device size and improvements in operational range. The behaviour is analytically modelled and verified through simulations. A prototype device was designed and microfabricated to experimentally validate the design principles. Compared to pre-curved nonlinear springs, the proposed design results in an 11-fold reduction in bias force, a 100-fold reduction in bias displacement, and a reduction in mechanical stiffness by a factor of 520. These results were verified through experiments conducted on a microfabricated accelerometer with an on-chip optical interferometer. Test results reveal an extended linear range of better than 150,mathrm{mg}, a bias force of 0.3 mathrm{mN}, and a bias displacement of 10 mathrm{mu m}, measured with an integrated optical interferometer with a displacement noise floor of 40 mathrm{pm}/sqrt{mathrm{Hz}} at 2 mathrm{Hz} and sensitivity of {194}^{circ }/mathrm{mg}.

Cantwell, CJ, Schroeder, ZS, Marshall-Ciochon, LK, Campbell, BA, Taber, CB, and Suchomel, TJ. Force production and barbell velocity characteristics across multiple sets of different accentuated eccentric loading conditions. J Strength Cond Res XX(X): 000-000, 2025-The purpose of this study was to examine the impact that multiple accentuated eccentric loaded (AEL) back squat sets have on force production and barbell velocity characteristics within 2 different loading conditions. Sixteen resistance-trained men performed 3 sets of 3 back squat repetitions while using 100% of their 1 repetition maximum (1RM) during the eccentric phase of the first repetition and either 60% (100-60) or 80% (100-80) 1RM on the concentric phase of the first repetition and the eccentric-concentric phases of the subsequent 2 repetitions. Braking and propulsion net mean force, duration, and net impulse as well as mean and peak barbell velocity were compared between loading schemes and sets using a series of 2-way repeated measures ANOVA. Significantly greater propulsion net mean force and mean barbell velocity were produced during the 100-60 condition than during the 100-80 condition across all sets (p < 0.001). In addition, significantly greater (p < 0.001) set-averaged braking net mean force and net impulse and peak barbell velocity were produced during the 100-60 condition while greater braking and propulsion duration (p < 0.001) and net impulse (p = 0.031) were produced during the 100-80 condition. Within each loading condition, trivial-small differences existed across sets for all variables (g ≤ 0.39). Multiple sets of AEL back squats can be prescribed using 100-60 and 100-80 loading schemes without negatively affecting force or velocity characteristics. Strength and conditioning practitioners may prescribe 100-60 to enhance rapid force production characteristics and 100-80 to provide a strength stimulus to enhance force development.

Background/Objectives: This study examined the effects of a six-week eccentric–reactive training program on neuromechanical markers of lateral explosiveness, asymmetry, and stretch-shortening cycle (SSC) efficiency in elite male youth table tennis players. Fourteen national-level athletes (mean age = 16.6 years) were assigned to either an experimental group (EG, n = 7) or a control group (CG, n = 7). EG performed flywheel squats and lateral depth jumps three times per week, while CG maintained regular training. Pre- and post-intervention testing included countermovement jumps, reactive strength index (RSI_DJ), force asymmetry, time-to-stabilization, SSC efficiency, and energy transfer ratio (ETR), measured via force plates, EMG, and inertial sensors. Methods: Multi-dimensional statistical analysis revealed coordinated improvements in explosive power and movement efficiency following eccentric training that were not visible when examining individual measures separately. Athletes in the training group showed enhanced neuromechanical control and developed more efficient movement patterns compared to controls. The analysis successfully identified distinct performance profiles and demonstrated that the training program improved explosive characteristics in elite table tennis players. Results: Univariate ANOVAs showed no significant Group × Time effects for RSI_DJ, ETR, or SSC_Eff, although RSI_DJ displayed a moderate effect size in EG (d = 0.47, 95% CI [0.12, 0.82], p = 0.043). In contrast, MANOVA confirmed a significant multivariate Group × Time interaction (p = 0.013), demonstrating integrated neuromechanical adaptations. Regression analysis indicated lower baseline CMJ and RSI_DJ predicted greater RSI improvements. Conclusions: In conclusion, eccentric–reactive training promoted multidimensional neuromechanical adaptations in elite racket sport athletes, supporting the use of integrated monitoring and targeted eccentric loading to enhance lateral explosiveness and efficiency.

Hamstring injuries are frequent in sports, often linked to eccentric overloading during sprinting. While eccentric strengthening, like Nordic curls and hip extensions, is common, the impact of exercise symmetry (unilateral vs. bilateral) on neuromuscular control remains unclear. This study aimed to investigate regional/task-specific neuromuscular strategies during unilateral and bilateral eccentric loading of the same exercises. Twenty-five healthy and physically active young men (age: 24.52 ± 3.82 years; height: 175.53 ± 5.44 cm; weight: 72.06 ± 7.44 kg) were recruited based on physical activity screening, with the exclusion criteria including recent lower limb injuries. Participants performed unilateral and bilateral curls and extensions with surface electromyography on hamstrings, gluteus maximus, and trunk stabilisers. Parameters like root mean square and median frequency were extracted and statistically compared. Unilateral execution generally elicited higher muscle activation, particularly in middle hamstring regions (30.65% to 38.38% in RMS, r = −0.84 to −0.77, pFDR < 0.001). Frequency differences revealed region-specific neuromuscular strategies. Intra-hamstring comparisons revealed significantly higher median frequencies in the BF50 and ST30 regions at their respective anatomical locations (dz = −1.90 to 1.34, all pFDR < 0.001). These findings suggest that exercise symmetry and anatomical specialisation jointly shape neuromuscular control, with implications for designing eccentric training to reduce injury risk.

Immediate effect of a combined neuromuscular electrical stimulation and eccentric load session on acute muscle swelling of the abductor hallucis.

PurposeThe purpose of this study was to compare the effects of supramaximal and submaximal accentuated eccentric loading (AEL) on lower-body function and hypertrophy during a short-term basic strength block.MethodsTwenty-two trained male students (20.64 ± 1.92 years, 177.07 ± 4.17 cm, 73.08 ± 4.44 kg) were assigned to two experimental groups based on baseline strength: the supramaximal loading group (SUPRA, 120%/70% one repetition maximum [1RM], n = 11) and the submaximal loading group (SUB, 95%/70% 1RM, n = 11), both groups applying eccentric overload during each repetition. Both groups trained twice weekly for 4 weeks (3 sets × 5 reps). The pre- and post-tests included rectus femoris cross-sectional area (RFCSA), countermovement jump height (CMJH), back squat 1RM, and 50% 1RM squat failure volume load (SFVL).ResultsA statistically significant main effect of time was observed for all variables (P < 0.05), but no statistically significant group × time interaction effects were found for any variable (P > 0.05). Both the SUPRA and SUB showed no statistically significant improvements in RFCSA, with trivial changes observed (P > 0.05, Hedges’ g = 0.13 and 0.10, respectively). Both the SUPRA and SUB showed statistically significant improvements in CMJH, 1RM, and SFVL (P < 0.05), with similar changes in CMJH (Hedges’ g = 0.31 and 0.22, respectively) and 1RM (Hedges’ g = 0.46 and 0.38, respectively). In SFVL, the SUPRA showed slightly greater improvements than the SUB (Hedges’ g = 0.43 and 0.19, respectively).ConclusionsThe results indicate that AEL training is effective in short-term training, with supramaximal and submaximal AEL producing similar improvements in outcomes. Therefore, submaximal AEL can serve as a feasible alternative to supramaximal AEL for physically active and healthy practitioners in a short-term basic strength block.

The purpose of this study was to investigate the acute responses of accentuated eccentric loaded (AEL) back squats to induce a post activation performance enhancement (PAPE) effect in youth athletes across three jump conditions: countermovement jump (CMJ), squat jump (SJ), and novel propulsive-only jump (POJ). Fifteen participants (age: 15.6 ± 1.1 years; RT experience: 1.3 ± 0.9 years; relative strength (back squat 1RM: body mass; 1.32 ± 0.3) completed three sessions (one familiarization, two experimental). AEL interventions were performed on each experimental session (3 sets x 3 repetitions, with only the initial repetition of each set was overloaded during the eccentric phase followed by 2 full repetitions of nonvarying loads) (ECC: 95%, 105%, 115%; CON: 60% 1RM) with pre- and post-testing (3 min, 6 min, 9 min, 12 min). Random assignment to either (a) CMJ, (b1) SJ+POJ, or (b2) POJ+SJ, where jump height (JH), net propulsive impulse (NPI) and peak relative propulsive power (PrPP) were assessed for each jump. Three 3x5 repeated measures ANOVAs were used to analyze each dependent variable across jump conditions and time with a level of significance of ρ ≤ 0.05. Results revealed a significant increase in POJ JH performance at 9 min (+12.26% ± 13.65%, p &lt; 0.05), while CMJ and SJ performance did not show statistically differences from pre-testing. JH performances peaked at 12 min for CMJ (+2.22% ± 7.71%) and SJ (+5.03% ± 12.77%) but did not reach statistical significance. These findings suggest that male high school basketball players may realize superior or unaffected jump performances at 9-12 min post-supramaximal AEL back squats. In addition, no significant deficits in performance outcomes were found for any condition from pre- to post-testing.

Abstract Cylindrical shell structures are widely used in engineering applications, particularly in ships and aircraft, due to their high strength-to-weight ratio and efficiency in resisting compressive loads. However, these structures are susceptible to failure through buckling, especially when imperfections such as load eccentricity, thickness variation, and initial geometric deviations are present. This study examines the structural response of thin-walled cylindrical shells subjected to axial compression, taking into account various imperfections. A finite element (FE) approach using ABAQUS software was employed and validated against previous experimental data. A parametric study was conducted using varying load eccentricity, initial geometric imperfections, and longitudinal thickness. The results show that load eccentricity significantly reduces the ultimate load and shifts the location of deformation. Both geometric and thickness imperfections also affect structural strength and the location of buckling. These findings enhance the reliability and safety of cylindrical shell designs in engineering applications.

Tendon injuries are a prevalent and challenging concern in athletic populations, often leading to prolonged downtime, impaired performance, and risk of reinjury. A diverse array of mechanisms can contribute to the development of tendinopathy or tendon rupture. This review discusses the current evidence on recovery strategies post-tendon injury, focusing on the mechanisms of tendon healing, rehabilitation protocols, and return-to-sport criteria. Emphasis is placed on the biological and mechanical aspects of tendon regeneration, alongside clinical applications such as eccentric loading, regenerative protocols, and neuromuscular re-education. Furthermore, the role of emerging modalities, including platelet-rich plasma (PRP), shockwave therapy, and nutritional supplementation, is evaluated. The review also highlights gaps in the literature and suggests directions for future research to optimise recovery and performance outcomes in athletes.

This study conducts a comparative experimental analysis of two soil improvement methods—geogrid reinforcement and skirted foundations—used beneath circular footings on loose sandy soils. While both techniques are well documented, their combined assessment is limited in the existing literature. In this study, sixty-four small-scale physical model tests were conducted in which footings were subjected to concentric and eccentric vertical loads. The results demonstrated that both improvement methods significantly enhance the foundation performance. Loosely cylindrical skirted foundations increase the bearing capacity by confining the soil and reducing the lateral movement; however, geogrid reinforcement performs better. The optimal spacing for geogrid layers (h) was 0.4 times the footing diameter, the ideal configuration for loosely cylindrical skirted foundations was a diameter (DS) equal to 1.4D, and a length (LS) equal to 1.5D. Although smaller skirts are less affected by eccentric loading, they did not show any significant improvement in performance. It was also found that the eccentric loads affect the loosely skirted foundations less than the geogrid reinforcement. Still, the latter generally performs better than the loosely skirted foundations in increasing the load-bearing capacity of the circular footings on sandy soil. The results are significant for the design of towers, heavy infrastructure foundations, and other constructions where the increased load-bearing capacity and reduced settlement are essential.

In this study, we developed a finite element model for fatigue fracture to investigate crack initiation in pipes under fatigue fracture. Under eccentric wheel loading, the stress concentration positions on the V-notch cross-section of the pipe varied continuously. Owing to the V-notch, stress concentration primarily occurred on the pipe’s outer surface. Thus, crack initiation occurred on the flank of the V-notch and was influenced by the applied load. Experiments under different loading modes revealed that under alternating and linear loads, the crack initiation and propagation faster, with the outer side expanding more quickly than the inner side. Additionally, constant tensile and monotonic loads affected the degree of crack opening and axial stress, accelerating crack expansion. The pipe diameter, clamping force arm, and loading force arm influenced the crack initiation position. At a constant outer diameter and clamping arm, the crack initiation angle of the pipe increased with the loading arm, promoting the precise separation of the pipe.