Axial Tensile Force Research Articles

Seismic Performance of Pile Groups under Liquefaction-Induced Lateral Spreading: Insights from Advanced Numerical Modeling

Post-earthquake investigations have shown that piles in liquefiable soils are highly susceptible to damage, especially in sloping sites. This study examines the seismic performance of pile groups with lateral spreading through advanced numerical modeling. A three-dimensional finite element model, validated against large-scale shaking table test results, is implemented to capture the key mechanisms driving the dynamic response of pile groups under both inertial and kinematic loading conditions. Parametric seismic response analyses are conducted to compare the behavior of batter and vertical piles under varying ground motion intensities. The results indicate that batter piles experience increased axial compressive and tensile forces compared to vertical piles, up to 70% and 20%, respectively. However, batter piles provide enhanced lateral stiffness and shear resistance compared to vertical piles, reducing horizontal displacements by up to 20% and tilting the cap by 85% under strong ground motion. The results demonstrate that batter piles not only enhance the overall seismic stability of the structure but also mitigate the risk of liquefaction-induced lateral spreading in the near-field through pile-pinning effects. While vertical piles are more commonly used in practice, the distinct advantages of batter piles for seismic stability highlighted in this study may encourage using more advanced numerical modeling in engineering projects.

Uncertainty-informed identification of tie-rod mechanical properties in monumental buildings

Tie-rods are classic structural elements that have been used for centuries to enhance stability in historic masonry buildings and offer valuable insights into structural performance over time through dynamic vibration measurements. This paper tackles the inverse problem, aiming to quantify uncertainties in mechanical properties, tensile axial force and boundary conditions of tie-rods based on experimental vibration frequencies. The approach assumes known probabilistic models for random parameters, such as mass per unit length, bending stiffness, tensile force and boundary conditions, with certain parameters requiring estimation. Finite dimensional models, i.e., deterministic functions in time and/or space, and a finite number of random variables are employed to discretize both physical and probability spaces. The paper concludes with a Monte Carlo simulation, that provides a comprehensive characterization of uncertainties and the best estimates for unknown features, including mass per unit length, stiffness, boundary conditions and tensile force necessary for achieving target free vibration modal parameters, i.e. natural frequencies.

Experimental Investigation of post-installed anchors’ behavior under axial tensile force

Experimental Investigation of post-installed anchors’ behavior under axial tensile force

RC FRAME RESISTANCE TO PROGRESSIVE COLLAPSE CONSIDERING CRACK OPENING EFFECTS

In this paper, an approach is developed to account for the effect of discrete cracks on the response of reinforced concrete building frames under a column failure scenario. The approach implies the introduction of traditional finite element models of discrete ties that take into account the relationship between moments and rotations, considering the specifics of the performance of materials, sections, and structures under conditions of redistribution of forces as a result of initial local failure in the structural system of a building. Validation of the proposed approach is performed on the experimental data. Also, it is compared with the modeling results of the existing approaches. The effect of discrete cracking on the deformed state of reinforced concrete building frames under the scenario of column failure is established. The discrete cracks practically did not affect the values of axial forces in the elements. However, for bending moments within the proposed method, a decrease was observed in comparison with the traditional approach. The analysis of the diagrams shows that for reinforced concrete frames with 3 and 5 stories, there is an excess of tensile axial forces in the beam over the values according to the traditional calculation method.

Investigation on Fracture Behavior of Electroslag Welding Joint with High-Performance Steel

This study aimed to investigate fracture behavior of electroslag welding (ESW) joint with 590-N/mm2 class steel using numerical analysis, covering a range of material scales in the structural level. The extended Mohr–Coulomb (EMC) fracture criterion was employed for finite element analysis (FEA). Uniaxial tensile test and three-point bending test were conducted to analyze the fracture behavior from the material scale and calibrate the fracture criterion. The test specimens consisted of the base metal, heat-affected-zone metal, and welding metal obtained from an ESW joint with a 590 N/mm2 class steel. Subsequently, FEA was conducted for a biaxial tensile test to investigate fracture behavior at a structural scale and verify the feasibility and accuracy of the calibrated fracture criterion. The comparison between the results from the FEA and test suggests that the FEA based on the EMC fracture criterion can accurately predict fracture behavior but tends to overestimate the bearing capacity. Thereafter, the effect of axial force on column was quantitatively investigated. The results suggest that the existence of tensile axial force at column decreases the ductility of ESW joint and shifts the fracture locus from the welding metal to heat-affected zone. However, the force has minimal influence on the pop-in load. Finally, the feasibility of applying the current Japanese specifications designated for the 490 N/mm2 class steel for the 590 N/mm2 class steel was examined. The results indicate that the provision can serve as a safe and reliable guideline for the 590 N/mm2 class steel as well.

Progressive Collapse Behavior of a Precast Reinforced Concrete Frame System with Layered Beams

A possible way to improve the structural safety and robustness of precast building structures is to develop effective precast frame systems with layered beams, which combine prefabricated parts with cast-in situ ordinary concrete, high-performance concrete, fiber concrete, or FRP. The paper provides a new type of precast reinforced concrete frame system with layered beams for rapidly erected multi-story buildings resistant to accidental actions. Using a combination of the variational method and two-level design schemes, a simplified analytical model has been developed for structural analysis of the precast reinforced concrete frame system, both for serviceable and ultimate limit states as well as for accidental actions. The proposed model allows for determining shear deformations and the formation and opening of longitudinal cracks in the intermediate contact zone between precast and monolithic parts of reinforced concrete structural elements of the frame, as well as the formation and opening of normal cracks because of the action of axial tensile force or bending moment in these elements. The design model was validated by comparing the calculated and experimental data obtained from testing scaled models of the precast reinforced concrete frame system with layered beams. The paper investigates and thoroughly analyzes the factors affecting the stiffness and bearing capacity of the intermediate contact zone, discusses the criteria for the formation of shear cracks along the contact zone of precast and monolithic concrete, and examines the change in the stiffness and dissipative properties of layered elements at different stages of their static–dynamic loading. The robustness of the experimental models of the structural system was not ensured under the specified load, section dimensions, and reinforcement scheme. Following an accidental action, longitudinal cracks were observed in the contact joint between the monolithic and prefabricated parts in the layered beams. This occurred almost simultaneously with the opening of normal cracks in adjacent sections. A comprehensive analysis of the results indicated a satisfactory degree of agreement between the proposed semi-analytical model and the test data.

Optimization of Hanger Spacing of Steel Arch Bridges Using Dynamic Loads

Bridges are basic infrastructure that must be met to create regional connectivity in Indonesia. One type of bridge that is often used is a curved bridge, which has the advantages of high strength, attractiveness, aesthetics and economy. In order to accelerate the development of bridge infrastructure, an efficient innovation in curved bridge design is needed. The development of curved bridge structures to achieve efficient designs has received much attention in several decades. However, researchers have only focused on optimising the geometry variation of the arch height. Therefore, the aim of this research is to innovate the optimisation of the hanger spacing on the arch bridge structure. In order to obtain optimal results, a bridge model is carried out by varying the hanger spacing of the centre model with a hanger spacing ratio of (1.3 - 1.1 - 0.9 - 0.7), a flat model with a hanger spacing ratio of (1 - 1 - 1 - 1) and an edge model with a hanger spacing ratio of (0.7 - 0.9 - 1.1 - 1.3), so that from the three models, the effect of hanger location on three conditions is obtained. Each model is modelled in the SAP2000 software and given a bridge service load to obtain the internal forces and deflections that occur. The output of the internal force and deflection is then analysed to determine the effect of the location of the bridge service hanger. The serviceability of the bridge is also analysed by calculating the ratio between the weight of the bridge and the deflection that occurs. The results of the analysis show that the location of the hanger affects the performance of the arch bridge structure. The centre model bridge design produces the most efficient structural performance in resisting the compressive axial forces and moments that occur, and produces the least deflection. Meanwhile, the edge model will provide the most efficient structural performance in resisting tensile axial forces. By referring to the results of the bridge weight to deflection ratio analysis, it can be concluded that the centre model produces the most efficient structural design when compared to other curved bridge models.

Bayesian Updating for Random Tensile Force Identification of Ancient Tie Rods Using Modal Data

Tie rods play a crucial role in civil engineering, particularly in controlling lateral thrusts in arches and vaults, and enhancing the structural integrity of masonry buildings, both historic and contemporary. Accurately assessing the tensile axial forces in tie rods is challenging due to the limitations of existing methodologies. These methodologies often rely on indirect measurements, computational models, and optimization procedures, resulting in single-point solutions and neglecting both modeling and measurement uncertainties. This study introduces a novel Bayesian updating framework to effectively address these limitations. The framework aims to accurately identify the structural parameters influencing tie rod behavior and estimate uncertainties using natural frequencies as references. A key innovation lies in the mathematical formulation of Bayesian updating, which is founded upon the definition of computational models integrating uncertain updating parameters and latent random variables derived from a rigorous sensitivity analysis aimed at quantifying the impact of the updating parameters on the natural frequencies. Notably, the application of Bayesian updating to the structural identification problem of ancient tie rods represents a significant advancement. The framework provides a comprehensive description of the uncertainties associated with computational models, offering valuable insights for practitioners and researchers alike. Moreover, the results of the sensitivity analysis serve as a valuable tool for setting up inverse problems geared towards accurately identifying tensile axial forces.

Effects of prestress in the coating of an elastic disk

An elastic disk is coated with an elastic rod, uniformly prestressed with a tensile or compressive axial force. The prestress state is assumed to be induced by three different models of external radial load or by ‘shrink-fit’ forcing the coating onto the disk. The prestressed coating/disk system, when loaded with an additional and arbitrary incremental external load, experiences incremental displacement, strain, and stress, which are solved via complex potentials. The analysis incorporates models for both perfect and imperfect bonding at the coating/disk interface. The derived solution highlights the significant influence not only of the prestress but also of the method employed to generate it. These two factors lead, in different ways, to a loss or an increase in incremental stiffness for compressive or tensile prestress. The first bifurcation load of the structure (which differs for different prestress generations) is determined in a perturbative way. The results emphasize the importance of modelling the load and may find applications in flexible electronics and robot arms subject to pressure or uniformly-distributed radial forces.

Tensile behavior of a novel self-locking inter-module connection in modular steel buildings

Modular steel buildings (MSBs) consist of complete steel modules and inter-module connections; the latter plays a crucial role in assembly efficacy on-site and in resisting the tension load at the base of a high-rise modular building subjected to lateral loads. This paper investigates the tensile performance of the proposed self-locking inter-module connection. Two full-scale experiments were conducted to evaluate the axial tensile behavior of this innovative connection. The mechanical properties of the self-locking inter-module connection were obtained and analyzed, including the failure modes, ultimate bearing capacity, and strain distribution. Under axial tension load, the self-locking inter-module connection exhibited adequate load-carrying capacity and ductility, as evidenced by the results. The refined finite element (FE) model of the self-locking inter-module connection was developed and validated against experimental data. Then, FE modeling was used to further investigate the working mechanism of the self-locking inter-module connection under axial tensile force. Two essential parameters were considered, including the bottom plate thickness of the upper corner fitting and the top plate thickness of the lower tenon. The numerical results demonstrated that the failure mode of such a self-locking inter-module connection was dependent on the relative relationship of the aforementioned two key parameters, which is reflected by the ratio (Kt) of the vertical shear area of the bottom plate of the upper corner fitting and the top plate of the lower tenon. Considering tensile resistances and material strength utilization, a range of values for the parameter Kt and design recommendations were provided.

ANALYSIS OF THE CAPACITY OF A WARREN TYPE STEEL FRAME BRIDGE USING MIDAS CIVIL 2019 SOFTWARE

There are two access bridges that have different functions, i.e., to cross the Ciliwung river as an access road from the RSCM Kencana building to RSCM Kirana, where there is access to the bridge that is specifically for car/motorcycle riders and a special bridge for pedestrians. However, the density of motorists and pedestrians can hinder traffic access. Thus, supporting infrastructure was built, namely a vehicle bridge and connecting pedestrians from the Kencana RSCM building to the Kirana RSCM building. The type of built bridge is a concrete slab steel frame bridge. This study aims to determine the values of the ultimate moment, shear, and axial forces that occur with the object viewed from the longitudinal and transverse girders whether they exceed the nominal profile value or not, and the deflections that occur on the behavior of the structure on the bridge based on SNI 1725:2016 loading with the aisstance of the MIDAS Civil 2019 software. The results of the calculation and capital analysis on the MIDAS Civil 2019 software, the values of the internal forces on the object under review do not exceed the nominal strength value of the profile. First, the girder extends against ultimate moment of ϕMn ≥ Mu = 3.762,080 kNm ≥ 528,869 kNm, against shear force ϕVn ≥ Vu = 1.095,444 kN ≥ 909,282 kN, against axial compressive force ϕPn ≥ Pu = 8.532,876 k N ≥ 3.115,265 kN, to the axial tensile force ϕPn ≥ Pu 7.726,842 kN ≥ 2.434,744 kN. Second, the transverse girder with respect to the ultimate moment of ϕMn ≥ Mu = 1.242,046 kNm ≥ 53,723 kNm, against the shear force ϕVn ≥ Vu=1.076,400 kN ≥ 81,513 kN, against the axial compressive force ϕPn ≥ Pu = 3.805,349 kN ≥ 255,812 kN .The deflection value that occurs at the ultimate state of the structural behavior of the bridge is 48.70 mm, this value is smaller than the allowable deflection of 55 mm, making the bridge structure is safe when it receives the ultimate load.

Tensile theoretical modeling and auxetic behavior analyzing of negative Poisson’s ratio yarn

In this paper, the tensile models of the negative Poisson’s ratio yarn with incompressible component yarn and compressible component yarn are constructed. The theoretical Poisson’s ratio curves exhibit the same trend as the experiment. Compared with the theoretical model of incompressible component yarns, a 14% reduction was found in the maximum negative Poisson’s ratio value in the compressible component yarns model. Additionally, the modified theoretical model was established to improve further the accuracy of the model. Both the variation trend and Poisson’s ratio value of the theoretical curves are highly consistent with the experimental results, and the average difference rate of the maximum Poisson’s ratio value is below 10%, which proves the effectiveness of the corrected theoretical model in predicting the auxetic behavior. Our theoretical model not only considers the initial helical path of the wrap yarn could not be completely horizontally straightened when it is just subject to an axial tensile force but also takes the influence of component yarn sectional shape changes into account. The as-constructed theoretical model is more realistic and can guide the design of negative Poisson’s ratio yarn and optimize the theoretical modeling method.

Necking of thin-walled cylinders via bifurcation of incompressible nonlinear elastic solids.

Necking localization under quasi-static uniaxial tension is experimentally observed in ductile thin-walled cylindrical tubes, made of soft polypropylene. Necking nucleates at multiple locations along the tube and spreads throughout, involving the occurrence of higher-order modes, evidencing trefoil and fourth-foiled (but rarely even fifth-foiled) shaped cross-sections. No evidence of such a complicated necking occurrence and growth was found in other ductile materials for thin-walled cylinders under quasi-static loading. With the aim of modelling this phenomenon, as well as all other possible bifurcations, a two-dimensional formulation is introduced, in which only the mean surface of the tube is considered, paralleling the celebrated Flügge 's treatment of axially-compressed cylindrical shells. This treatment is extended to include tension and a broad class of nonlinear-hyperelastic constitutive law for the material, which is also assumed to be incompressible. The theoretical framework leads to a number of new results, not only for tensile axial force (where necking is modelled and, as a particular case, the classic Considère formula is shown to represent the limit of very thin tubes), but also for compressive force, providing closed-form formulae for wrinkling (showing that a direct application of the Flügge equation can be incorrect) and for Euler buckling. It is shown that the J2-deformation theory of plasticity (the simplest constitutive assumption to mimic through nonlinear elasticity the plastic branch of a material) captures multiple necking and occurrence of higher-order modes, so that experiments are explained. The presented results are important for several applications, ranging from aerospace and automotive engineering to the vascular mechanobiology, where a thin-walled tube (for instance an artery, or a catheter, or a stent) may become unstable not only in compression, but also in tension.

Cyclic Behavior of a Novel MADAS Damper with No Axial Force and Improved Seismic Performance (Experimental, Numerical, and Analytical Assessment)

ABSTRACT Axial forces are generated in the plates of ADAS-yielding dampers when subjected to lateral loading due to their boundary conditions. This on one hand can lead to an increase in strain level of the plates and accelerate the damage process, while on the other hand, the interaction of the bending moment with the tensile axial force leads to increasing strength, which is undesirable in the performance of ductile members. In this paper, a modified ADAS device (MADAS) is introduced to prevent undesirable interaction of axial forces, and its cyclic behavior is evaluated both experimentally and numerically. To this end, in the first step, two test specimens with different number of connection pins were prepared and subjected to cyclic loading in a rigid frame. Experimental and numerical results have shown that due to the removal of the constraint in the vertical direction, the level of forces produced by the damper is almost constant and the X-shaped plates have been able to tolerate significant number of cycles before crack initiation. Afterwards, the cyclic performance of ADAS and MADAS dampers was numerically compared individually and also when placed in the frame. Furthermore, in the frame equipped with ADAS damper, the increase in the level of forces produced by the damper led to the buckling of the braces, while the level of generated forces was totally in the expected range in the frame equipped with MADAS damper.

Progressive collapse analysis and retrofit of a steel-RC building considering catenary effect

Despite their low probability of occurrence, the consequences of abnormal loads may be very important, both in economic terms and in terms of human lives. This has stimulated the development of strengthening and retrofitting techniques to mitigate the risk of progressive collapse of buildings. However, their application to real-scale buildings is still lacking. This paper describes the progressive collapse analysis and retrofit of a steel-reinforced concrete hospital building. The progressive collapse performance under different column removal scenarios is investigated using both nonlinear static and dynamic analyses. A two-step pushdown analysis procedure is developed to estimate the dynamic amplification factor (DIF) to partially compensate for the dynamic effects. The results have revealed the vulnerability of the building due to the low tensile axial resistance of the beam-to-column connections. Both the hypothesis of DIF = 2 and the almost inversely proportional relationship between DIF and vertical deflection have proven to be ineffective due to the catenary effect. A retrofit solution is proposed based on an outrigger-belt truss system on the rooftop level. The results show the effectiveness of the retrofit strategy. The displacement dynamic response of the retrofitted structure is significantly reduced if compared to the original structure since it goes from about 20 cm to less than 1 cm. However, the tensile strength of column-to-column connections of the top three floors is inadequate and should be increased. To this aim, a strengthening intervention is developed to increase the tensile strength from 565 kN to 965 kN, thus allowing the tensile axial forces caused by the column removed to be resisted.

Large-Strain Vibrations of Axially Stretched Hyperelastic Rods

Fast-moving soft robotics usually suffer large-strain deformation with a relatively high velocity. To improve their performance, it is necessary to study the underly dynamical mechanism. However, the inherent strong material nonlinearity brings considerable difficulties in modeling and calculating the soft structure’s nonlinear dynamics. This work focuses on the large-strain vibrations of the hyperelastic rod under an axial tensile force. Several typical hyperelastic models, including the neo-Hookean, Mooney, and Yeoh models, are used to derive the equations governing the rod’s dynamics. The equations based on these models are relatively complex, and their corresponding numerical calculation diverges in some cases. Therefore, a reference stretch ratio(s) polynomial fitting (RSRPF) model is proposed to derive the concise governing equation. Such a governing equation is effectively solved by the combination of the Galerkin discretization and the fourth-order Runge–Kutta integration algorithm. The correctness of the developed model and the employed algorithm is verified by comparing with the previous data of a hyperelastic membrane. In most cases, the rod periodically vibrates under a periodic tensile force. However, when the structural damping is small and the load frequency approaches the resonant frequency, the hyperelastic rod may quasi-periodically vibrate. The revealed large-strain vibration mechanism is supposed to be useful for guiding the dynamical design of soft structures.

Spinolaminar locking plates improve fixation strength compared to pedicle screws: a biomechanical analysis.

Pedicle screw loosening is a significant complication of posterior spinal fixation, particularly among osteoporotic patients and in deformity constructs. In orthopedic trauma surgery, locking plates and screws have revolutionized the fixation of osteoporotic fractures. We have combined the traumatology principle of fixed-angle locking plate fixation with the spine principles of segmental instrumentation. A novel spinolaminar locking plate was designed based on morphometric studies of human thoracolumbar vertebrae. The plates were fixed to cadaveric human lumbar spines and connected to form 1-level L1-L2 or L4-L5 constructs and compared to similar pedicle screw constructs. Pure moment testing was performed to assess range of motion before and after 30,000 cycles of cyclic fatigue. Post-fatigue fixture pullout strength was assessed by applying a continuous axial tensile force oriented to the principal axis of the pedicle until pullout was observed. Spinolaminar plate fixation resulted in superior pullout strength compared to pedicle screws (1,065 ± 400N vs. 714 ± 284N, p = 0.028). Spinolaminar plates performed equivalently to pedicle screws in range of motion reduction during flexion/extension and axial rotation. Pedicle screws outperformed the spinolaminar plates in lateral bending. Finally, no spinolaminar constructs failed during cyclic fatigue testing, whereas one pedicle screw construct did. The spinolaminar locking plate maintained adequate fixation post-fatigue, particularly in flexion/extension and axial rotation compared to pedicle screws. Moreover, spinolaminar plates were superior to pedicle screw fixation with respect to cyclic fatiguing and pullout strength. The spinolaminar plates offer a viable option for posterior lumbar instrumentation in the adult spine.

Deflection reduction of the guideway of aerial PRT systems by horizontal supports

Controlling the deflection of the aerial personal rapid transit (PRT) structure is crucial to the system’s riding comfort and energy efficiency. A nonlinear elastic analysis of a beam under combined axial and transverse loads is conducted to show a new mechanism to stiffen the PRT structure by using horizontal support. Although the classic beam theory often neglects the effect of the tensile axial force, when the deflection caused by the transverse load is large, the tensile axial force may significantly contribute to the mitigation of overall deflection, particularly for thin, long beams. Using the governing equation of beam with an axial force, the Green’s function is obtained for different boundary conditions. To demonstrate and validate the theory, three-point bending tests have been conducted for three boundary conditions: (1) two roller supports with a varying horizontal load; (2) two clamped supports with a varying horizontal load; and (3) two fixed supports with rigid constraints, which passively induce a tensile force by the transverse load. The formulation captures the nonlinear elastic behavior of the beams with horizontal constraints or axial forces, which shows that the maximum deflection of the 11 beams can reduce 38%–87% under the elastic load range. The Green’s function can be applied to arbitrary transverse loads in structural design. A smart cushion system is invented to provide horizontal support to the guideway of a lightweight, stiffened aerial PRT structure.

Analysis of a Large-Scale Physical Model of Geosynthetic-Reinforced Piled Embankment and Analytical Design Methods

The piled embankment represents one of the solutions for the realization of a soil body on a compressible subsoil where extended settlement or insufficient stability threatens the serviceability of related structures. Widely adopted analytical design procedures were analyzed: Marston’s formula and Hewlett and Randolph method contained in the British standard BS 8006-1, the German regulation EBGEO and the Dutch regulation CUR 226. Using these recommendations, the theoretical values of the individual parts of the load acting in the embankment and, subsequently, the values of the axial strain or tensile forces in the reinforcement were determined and compared with experimental data obtained from the tests in the large-scale physical model. For the presented case, without subsoil support, CUR 226 with the inverse load, which is recommended in the case of subsoil with low bearing capacity, shows better coincidence with the measured data. Overall, EBGEO and CUR 226 can be considered to be close to the real behavior of the piled embankment. Because of the frequent utilization of geosynthetic reinforcement and possible changes of subsoil parameters during the service life of the piled embankment, a rheological process of its elements should be investigated during the design process.

Mechanical properties of carbon steel under uniaxial static tension

With the continuous development of science and technology, carbon steel is widely used in production and life. Especially at the practical application level, in the engineering application, the analysis of the mechanical properties of carbon steel materials has become increasingly prominent. The tensile test is a mechanical property test in which a standard tensile specimen is pulled to fracture at a specified tensile speed under the continuous action of static axial tensile force. The force and elongation are continuously recorded during the tensile process so as to obtain its strength criterion and plasticity criterion. In this paper, the characteristics of mechanical properties of the high, medium, and low carbon steels under uniaxial static tension are discussed. The reasons for the different mechanical properties of steels with different carbon content are explained from a microscopic perspective. The study provides some basic assistance to those who need relevant information.