Lateral Load Research Articles

Effects of Local Scouring on Load-Bearing Behaviors of Monopile–Friction Wheel Hybrid Foundations on Sandy Deposit Soil under Lateral Loading

Effects of Local Scouring on Load-Bearing Behaviors of Monopile–Friction Wheel Hybrid Foundations on Sandy Deposit Soil under Lateral Loading

The Behavior of Horizontal Anchor Foundations Embedded in Sand under Uplift and Lateral Loads

The Behavior of Horizontal Anchor Foundations Embedded in Sand under Uplift and Lateral Loads

Comparative Analysis of Framed-Tube & Braced-Tube System in Tall Buildings Using ETABS

Abstract: Since the rigid frame became popular in the first half of the 20th century, tall buildings with structural systems have evolved. The development of underlying frameworks for tall structures lays on reasonable realism, economy of material utilization, effortlessness and polish, and worry for constructability. We are now able to build buildings that are ever higher thanks to cutting-edge building materials, sophisticated computational software, and sturdy structural systems. The rationale behind the creation of structural systems for tall buildings is to achieve architectural expression, ensure safety and serviceability, and make rational and effective use of materials. The use of composite structures, which combine the advantages of various materials, has been the trend in structural systems for tall buildings. In both static and dynamic conditions, these high-rise structures ought to be able to withstand a variety of lateral loads, such as wind load and earthquake load. This study examines the responses of the Framed Tube, Braced Tube, structural systems to various parameters such as Story displacement, Story drift, Story shear, and time period. The analysis focuses on 60-story structures situated in Seismic Zone III with medium soil conditions. The static analysis of the structures is conducted using the linear static method, which involves wind load calculations using the force coefficient method. On the other hand, the dynamic analysis is performed using the response spectrum method, with wind load calculations carried out using the gust factor calculation method.

Predictive abilities of constitutive models for clay under monotonic and cyclic loading: element tests and centrifuge experiments

A critical investigation of three constitutive models for clay by means of analyses of a sophisticated laboratory testing program and of centrifuge tests on monopiles in clay subjected to (cyclic) lateral loading is presented. Constitutive models of varying complexity, namely the basic Modified Cam Clay model, the hypoplastic model with Intergranular Strain (known as Clay hypoplasticity model) and the more recently proposed anisotropic visco-ISA model, are considered. From the simulations of the centrifuge tests with monotonic loading it is concluded that all three constitutive models give satisfactory results if a proper calibration of constitutive model parameters and proper initialisation of state variables is ensured. In the case of cyclic loading, the AVISA model is found to perform superior to the hypoplastic model with Intergranular Strain.

The Shear Effect of Large-Diameter Piles under Different Lateral Loading Levels: The Transfer Matrix Method

In various analytical models, modeling the behavior of large-diameter monopiles and piles can be challenging due to these foundations with huge body sizes carrying mechanisms of lateral loads to the surrounding soils. In this paper, the transfer matrix method with the Timoshenko beam theory was used to modify the shear rotation of pile sections under different loading stages, including serviceability limit stages and the ultimate loading stage. In this transfer matrix method, a large-diameter pile is considered according to the Timoshenko beam theory, and the recurring variables in the matrix equation are replaced with constants to simplify the calculation steps. Two model test cases were used to verify the accuracy of the method. Then, a series of comparisons between the Timoshenko beam and the Euler–Bernoulli beam theories, with the relative pile–soil stiffness being equal to 0.15, 0.45, and 0.75, was conducted to investigate the differences in pile response after considering the shear deformation. The results show that the effect of shear deformation of large-diameter piles changes with different loading levels. The values of the pile deformation based on the Timoshenko beam theory divided by those of that based on the Euler–Bernoulli beam theory were in the range of 1.0 to 1.10, and they increased slightly with increasing loads, reaching their maximum value, and then rapidly decreased to 1.0 when close to the ultimate lateral load; the maximum value was influenced by the relative pile–soil stiffness. Furthermore, the ratio of the shear rotation of the pile section to the slope of the deflection curve was in the range of 1.0 to 1.10; these also showed similar but more moderate trends compared with the values of pile deformation based on the Timoshenko beam theory divided by those of that based on the Euler–Bernoulli beam theory.

Fatigue Life Prediction and Verification of Railway Fastener Clip Based on Critical Plane Method

Accurately predicting the fatigue life of fastener clips is crucial for improving material processing technology, enhancing the anti-fatigue design level, and guiding the maintenance and repair of track structures. Conventional methods that solely evaluate the fatigue life of fastener clips based on the uniaxial stress index under displacement loads may lead to significant errors. In this paper, the stress field of a type-III clip under displacement loading conditions was numerically simulated based on fatigue test standards, and the fatigue life of the clip was analyzed using the Fatemi–Socie (FS) multiaxial fatigue criterion based on the critical plane method. A comparison with standard fatigue test results revealed that, under non-resonance conditions, the predicted position of the fatigue critical plane of the fastener clip coincided with the fracture surface observed at the middle of the measured small arc, with a life prediction error of 7.3%. To further investigate the predictive capability of the FS multiaxial fatigue criterion for the fatigue life of the fastener clip under resonance conditions, the stress levels of the clip under non-resonance and resonance conditions were compared through on-site testing, and the effects of inertial loads caused by vertical and lateral vibration acceleration on the stress field of the clip were analyzed in numerical simulation according to the results of clip acceleration tests; the fastener clip’s resonance fracture position and fatigue life were also predicted based on the aforementioned multiaxial fatigue criterion. To verify the accuracy of the predicted results, a testing method was proposed that equates the high-frequency resonant inertial load of the fastener clip to a low-frequency additional preload under the premise of consistent stress fields. A comparison with the numerical simulation results shows that considering only vertical inertial loads would result in a discrepancy between the measured fracture location and the actual one. Considering both vertical and lateral inertial loads, the fracture location (at the heel of the small arc) under resonance conditions could be accurately determined, with a life prediction error of 13.8%. Compared to the non-resonant displacement loading condition, the inertial loads caused by acceleration under resonance conditions led to a reduction in fatigue life of approximately 77.8%.

Evaluation on Damage Behavior under Bending and Lateral Compressive Load of CF/PEEK Round Rod Manufactured by Prepreg Tape Thermal Pultrusion Process

Evaluation on Damage Behavior under Bending and Lateral Compressive Load of CF/PEEK Round Rod Manufactured by Prepreg Tape Thermal Pultrusion Process

Seismic performance of brick masonry walls strengthened with engineered cementitious composites under lateral cyclic loads

Seismic performance of brick masonry walls strengthened with engineered cementitious composites under lateral cyclic loads

The effect of combined use of plybamboo sheathings and self-tapping screws in enhancing wood-frame shear wall performance

ABSTRACT Plybamboo panels are renewable and eco-friendly structural panels with high strength, good dimensional stability, and affordability, making them highly suitable for wood-frame construction. This study presents an experimental investigation of the wood-frame shear wall constructed with plybamboo-sheathing panels with self-tapping screws (STSs) subjected to monotonic and cyclic loadings. Performance parameters including shear strength, elastic shear modulus, ductility ratio, stiffness degradation, and energy dissipation were evaluated. Results indicate that the combined use of plybamboo sheathings and STSs can substantially reduce failures due to the tearing of sheathing, fastener head pull-through, and fastener withdrawal. The plybamboo-sheathed wood-frame shear walls with STSs had over 1.8 times shear strength and 1.4 times ultimate displacement than those of comparable wood-frame shear walls with nails, respectively, maintaining over 80% of their maximum lateral load capacity at a drift level over 4%. Moreover, the influence of aspect ratio and screw spacing on the elastic shear modulus, shear strength, and stiffness degradation of the plybamboo-sheathed wood-frame shear walls with STSs are consistent with those for common wood-frame shear walls.

Injection of anomalous-Hall current into a load circuit

The anomalous-Hall current injection is studied in a Hall device contacted to a lateral load circuit. This anomalous-Hall current is generated inside a Co75Gd25 ferrimagnetic Hall bar and injected into a lateral load circuit contacted at the edges. The current, the voltage, and the power are measured as a function of the magnetization states, the load resistance Rl, and the temperature. It is shown that (1) the resistance associated with the anomalous-Hall current flowing inside the Hall bar is that of the portion of the ferrimagnet located between the lateral contacts, (2) the role of the non-uniformity of the current due to the lateral contacts is small, (3) the maximum power efficiency of the current injection into the load circuit corresponds to the condition of the resistance matching of the two sub-circuits, and (4) this maximum power efficiency is of the order of the square of the anomalous-Hall angle. These observations are in agreement with recent predictions based on a non-equilibrium variational approach.

Analysis of Rectangular Plate with Opening by Finite Difference Method

Steel plates are commonly used to support lateral or vertical loads. Before the design of such a plate, analysis is performed to check the stability of plate for the proposed load. There are several methods for this analysis. In this research, a finite difference method (FDM) is proposed to analyze a rectangular steel plate. The plate is considered to be subjected to an arbitrary transverse uniformly distributed loading and is considered to be clamped at the two opposite edges and free at the other two edges. At first the plate is analyzed considering it to be completely solid and then it was re-analyzed considering a rectangular opening at its centre. The ordinary finite difference method is used to solve the governing differential equation of the plate deflection. The proposed method can be easily programmed to readily apply on a plate problem. The work covers the determination of displacement components at different points of the plate and checking the result by software (STAAD.Pro) analysis.

Analysis Seismic Behavior of Structures with Planar Imperfections: A Comprehensive Numerical Analysis

This paper presents a comprehensive approach to the seismic analysis and design of a tall hospital building, accounting for horizontal irregularities and employing equivalent static analysis (ESA) methodology. The study initiates with the collection of relevant site data and building specifications, including the identification and characterization of horizontal irregularities such as setbacks, mass distribution variations, and irregular floor plans. Equivalent static lateral loads are calculated based on applicable building codes and standards, taking into account the effects of horizontal irregularities on seismic response. Structural modeling and analysis are then conducted using sophisticated software to evaluate the building's behavior under seismic forces, considering the influence of irregularities on structural performance. Design criteria, encompassing drift limits, strength requirements, and detailing considerations for mitigating irregularity effects, are rigorously adhered to ensure compliance with safety regulations and performance objectives. The iterative process of evaluation and adjustment ensures optimal seismic performance and adherence to design criteria despite the presence of horizontal irregularities. Documentation of the analysis and design process, coupled with meticulous construction oversight, guarantees the implementation of a robust seismic design strategy tailored to the unique characteristics of the tall hospital building. Post-construction evaluations are carried out to validate predicted seismic performance, accounting for the influence of horizontal irregularities. Through collaborative efforts and adherence to best practices, the seismic design of the tall hospital building prioritizes safety and resilience, even in the face of horizontal irregularities, aiming to safeguard occupants and critical healthcare infrastructure during seismic events.

Failures of geometrically asymmetric steel-UHPC composite beams

Geometrically asymmetric steel-ultra-high performance concrete (UHPC) composite structures (SUCSs) suffer several typical failure modes during applications in structural engineering. But the competing mechanism of these failure modes remains a challenge to be urgently overcome. In the present paper, the failure modes of the geometrically asymmetric SUCSs under lateral loads are theoretically predicted and numerically studied. Considering both the geometric asymmetry of the structure and the tensile-compressive asymmetry of UHPC, a theoretical model is proposed to predict the critical failure load for each failure mode (e.g., bending and core shear), and then a failure mechanism map is constructed by comparing each critical failure load. The theoretical predictions are in line with the present numerical results and the previous experimental measurements. The results demonstrate that geometric asymmetry, together with some other geometric parameters and material properties, have remarkable influences on the failure modes of structures. This work provides an effective approach for predicting and designing the failure modes of geometrically asymmetric SUCSs in structural engineering applications, such as undersea tunnels, offshore platforms, and nuclear shielding walls.

Finite element analysis of locally strengthened stainless-steel tube under lateral impact loading

In this study, a Finite Element (FE) model of locally strengthened high-strength stainless-steel tube subjected to lateral impact loads is established using LS-DYNA to investigate its dynamic behaviours. The accuracy of the FE results is verified by comparing with the test results. The impact force, bending moment, stress and strain responses as well as the internal energy dissipation histories of the strengthened tube are analysed during the entire impact process. The results indicate that the impact resistance of the strengthened tube is obviously enhanced as compared to hollow stainless-steel tube. Furthermore, parametric studies are conducted to reveal the influence of axial compressive force, impact position, impact velocity and material strength on the impact behaviour of the strengthened tube. The results show that the application of axial compressive force reduced the impact force and increased the deformations of the strengthened tube. The impact resistance of the strengthened tube performed an increasing trend when moving the impact position towards the support and increasing the material strength. In addition, the increase of impact velocity significantly reduced the impact duration. Finally, design recommendations and process were proposed to facilitate the application of locally strengthened tube.

Seismic Performance of Full-Scale Autoclaved Aerated Concrete Panel-Assembled Walls: Experimental Study and Numerical Modeling

Prefabricated panel-assembled wall systems, comprising a confining frame and infill lightweight panels of autoclaved aerated concrete (AAC), are widely employed in framed structures. Different from studies on a main frame with infill walls, this study aimed to explore the seismic performance of partition walls, which were fabricated with AAC panel-assembled walls and located outside of the main frames. Two full-scale specimens, one with a door opening and the other without, were constructed and cyclic loading tests were executed to examine the failure modes, hysteresis characteristics, envelope curves, ductility, strength and stiffness degradation, as well as energy dissipation capacity of the AAC panel-assembled walls. Additionally, a restoring-force model for the panel-assembled walls was developed and a method for predicting the lateral load-bearing capacity of the AAC panel-assembled walls was proposed. The findings indicated that the panels enhanced the system’s lateral resistance, energy dissipation capacity, and deformation capability. The door frame increased the initial stiffness, peak lateral load and energy dissipation capacity of the AAC panel-assembled wall compared to the wall without a door frame. Compared to the specimen without a door frame, the peak lateral load of the specimen with a door frame increased by 19.7–30.1%. The deformation capacity of the panel-assembled walls aligned with the requirements for concrete framed structures.

Seismic performance of flexural reinforced concrete columns subjected to varying axial forces

This paper examines the influence of variable axial force on the seismic performance of flexural domain reinforced concrete (RC) columns through experimental testing of five full-scale specimens. The test results demonstrate that fluctuating axial force, when combined with simulated cyclic seismic loading, significantly impacts the flexural behavior of RC columns. The behavior of RC columns under fluctuating axial loads was markedly different from that of columns under constant axial loads. A notable observation was that the failure mode of the columns transitioned from ductile flexural failure to flexure-shear failure when comparing columns subjected to constant axial loads to those subjected to fluctuating axial loads that alternated between compression and tension. This study further demonstrated that the lateral load capacity of the columns, along with their deterioration, was significantly influenced by both the fluctuating pattern and intensity of the axial forces, as well as the displacement ductility. An empirical equation was proposed to estimate the residual lateral load capacity of flexural domain RC columns under varying axial forces, providing a practical tool for designers to assess the behavior of columns under different loading conditions. To corroborate the conclusions drawn from the experimental investigation and gain further insights into the influence of fluctuating axial force on the seismic behavior of flexural domain columns, this study additionally proposes a finite element (FE) model. According to the experimental and numerical results, an empirical equation to estimate the ultimate drift capacity of RC columns subjected to varying axial force is also proposed.

Experimental study on seismic performance of squat RC shear walls reinforced with hybrid steel and GFRP rebars

This laboratory study investigates the effect of using steel and glass fiber reinforced polymer (GFRP) rebars in shear walls with aspect ratios less than two. The study evaluates six full-scale shear walls subjected to constant axial load and cyclic lateral loading, with aspect ratios of 1.08 and 1.75. The aim is to analyze how the use of steel and GFRP rebars affects crack patterns, fracture, seismic performance, dissipated energy, and ductility of shear walls. The six specimens consist of two reference ones (SRC1 and SRC2) reinforced with steel rebars, two specimens (GRC1 and GRC2) reinforced with GFRP rebars, and two specimens (S-GRC1 and S-GRC2) reinforced with a hybrid of steel and GFRP rebars. The conclusions drawn suggest that employing a hybrid combination of steel and GFRP rebars resulted in a notable alteration of crack propagation behavior and failure mode, transitioning from flexural compression to flexural tension. Additionally, compared to the specimens reinforced solely with GFRP rebars, there was an observed expansion of the hysteresis curve. Additionally, parameters such as cumulative dissipated energy, ductility, and load modification factor based on ductility increased in the S-GRC1 and S-GRC2 specimens compared to the GRC1 and GRC2.

An enhanced understanding of the lateral response of large-diameter monopile: Development of a new P-y curve

The present design practices of laterally loaded monopiles tends to discretize the pile into a series of beam elements and connect each element to uncoupled non-linear springs, or P-y curves, to represent soil reactions. The prevailing design codes tend to support the use of a universal P-y curve irrespective of pile configuration, flexural rigidity, and soil rigidity index. However, accumulating evidence suggests otherwise, underscoring the imperative to revise formulas, especially for large diameter rigid monopiles. This study conducts a thorough examination of load transfer and failure mechanisms in large diameter monopiles subjected to monotonic lateral loading in clayey soil. A refined formula is proposed to estimate ultimate net soil resistance, rectifying deficiencies in prevailing design codes prone to underestimation. Findings reveal significant influence of soil rigidity index on the P-y curve of rigid monopiles. Consequently, endeavours are undertaken to develop a new P-y formulation integrating the pivotal role of soil rigidity index. The newly devised P-y curve is anticipated to propel advancements in the design of large diameter monopiles, pivotal in offshore renewable energy exploitation.

Water, Salt, and Ion Transport and Its Response to Water-Saving Irrigation in the Hetao Irrigation District Based on the SWAT-Salt Model

Soil salinization is one of the main hazards affecting the sustainable development of agriculture in the Hetao Irrigation District (HID) of Inner Mongolia. To grasp the water and salt transport patterns and spatial–temporal distribution characteristics of the HID at the regional scale, the improved Soil and Water Assessment Tool with a salinity module (SWAT-Salt) model was used to establish the distributed water and salt transport model for the watershed in this study. The results demonstrated that the modified model could more accurately represent the process of water and salt changes in the HID. The coefficient of determination (R2) in the simulation of streamflow and discharge salt loading was 0.83 and 0.86, respectively, and the Nash–Sutcliffe efficiency (NSE) was 0.80 and 0.74, respectively. Based on this, different hydrological processes (surface runoff, lateral flow, groundwater, soil seepage) as well as spatial–temporal distribution characteristics of water salinity in groundwater and soil were analyzed in the HID. Differences in groundwater and soil salinity in different land uses and soil types were also compared. Of these, surface runoff and lateral flow salt discharge loading are concentrated in the southwestern portion of the basin, while groundwater salt discharge loading is concentrated in the eastern as well as southwestern portions of the basin. The salt discharge loading from groundwater accounts for about 98.7% of the total salt discharge loading from all hydrological pathways and is the major contributing part of salt discharge from the irrigation area. Soil salinity increases gradually from west to east. Groundwater salinity (2946 mg/L) and soil water electrical conductivity (0.309 dS/m) were minimized in the cropland. Meanwhile, rational allocation of irrigation water can appropriately increase the amount of salt discharge loading. In conclusion, the model could provide a reference for the investigation of soil salinization and water–salt management measures in irrigation areas.

The behavior of reinforced concrete frames exposed to high temperature under cyclic load effect

Continued use of the structure through minor renovations and repairs without a complete and accurate determination of the extent of damage to the structure and its elements exposed to high temperature effects due to fire, etc. will cause more loss of life and property in the event of an earthquake that may occur later. The aim of this study is to determine the losses on the lateral load and energy damping capacities and stiffness of reinforced concrete frames exposed to 200, 400, 600 and 800 ℃ high temperatures for 60, 120 and 180 min. For this purpose, 13 reinforced concrete frame test elements with the same concrete and steel material properties and dimensions were produced. All reinforced concrete frame test members were brought to the specified target temperature within one hour and exposed to high temperature effects for 60, 120 and 180 min at these target temperatures. The test members then allowed cooling down on their own and when they reached room temperature, they removed from the oven and subjected to cyclic lateral loading tests. The data obtained from the cyclic lateral loading tests processed to obtain lateral load - horizontal displacement, stiffness - horizontal displacement, cumulative energy consumption - horizontal displacement and strength envelope curves for each test element. According to the results of the cyclic lateral loading tests, it was determined that the lateral load carrying capacities of the test members exposed to high temperature for 60, 120 and 180 min decreased by 24 %, 33.33 % and 36 % in push, and by 25.76 %, 37.6 % and 38.72 % in pull, respectively. In addition, the energy consumption of the test elements exposed to high temperature for 60, 120 and 180 min decreased by 30.98 %, 42.41 % and 39.62 %, respectively, compared to the reference test element. The initial stiffness of all test elements exposed to the high temperature effect decreased compared to the initial stiffness of the reference test element not exposed to the high temperature effect. According to these results, the effect of high temperature causes losses in many parameters that are of vital importance in the building elements, but also highly affects the earthquake behavior of the building.