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In literature, previous studies have focused on analyzing rienforced concrete (RC) columns with idealized end conditions when subjected to fire. In nature, full fixity or free rotation at column ends is not attained. Such ends may be considered partially restrained in rotation. This paper aims to shed a new light on the effect of different degrees of rotational restraint on the lateral deformation behavior of slender heated RC columns subjected to non-linear strain distributions produced by a time-dependent temperature history.

To find the strain distribution on the cross section, an iterative technique is adopted using Newton–Raphson method. By introducing a reliable calculation procedure, the lateral deformational behavior is expressed using numerical and searching techniques. A methodology is presented to calculate the effective length factor for RC columns at elevated temperature.

The results of the proposed model showed good agreement with available experimental test results. It was also found that the variation of rotational end restraint level has a considerable effect on the lateral deformation behavior of heated slender RC columns. In addition, the effectiveness and the validity of an analytical model should be verified by simultaneously validating the axial and lateral deformations. Moreover, the effective length factor for heated column is higher than that for the corresponding column at ambient temperature.

This paper shows the impact of different boundary conditions on the behavior of heated slender RC columns. It suggests powerful techniques to determine the lateral deflection and the effective length factor at high temperatures.

This paper aims to investigate the responses of single piles and pile groups due to tunneling-induced ground movements in a two-layered soil system. The analyses mainly focus on the additional single pile responses in terms of bending moment, lateral deflection, axial force, shaft resistance and pile settlement. Subsequently, a series of parametric studies were carried out to better understand the responses of single piles induced by tunneling. To give further understanding regarding the pile groups, a 2 × 2 pile group with two different pile head conditions, namely, free and capped, was considered.

Using the PLAXIS three-dimensional (3D) software, a full 3D numerical modeling is performed to investigate the effects of ground movements caused by tunneling on adjacent pile foundations. The numerical model was validated using centrifuge test data found in the literature. The relevance of the 3D model is also judged by comparison with the 2D plane strain model using the PLAXIS 2D code.

The numerical test results reveal that tunneling induces significant displacements and internal forces in nearby piles. The magnitude and distribution of internal forces depend mainly on the position of the pile toe relative to the tunnel depth and the distance between the pile and the vertical axis of the tunnel. As the volume loss increases from 1% to 3%, the apparent loss of pile capacity increases from 11% to 20%. By increasing the pile length from 0.5 to 1.5 times, the tunnel depth, the maximum pile settlement and lateral deflection decrease by about 63% and 18%, respectively. On the other hand, the maximum bending moment and axial load increase by about 7 and 13 times, respectively. When the pile is located at a distance of 2.5 times the tunnel diameter (Dt), the additional pile responses become insignificant. It was found that an increase in tunnel depth from 1.5Dt to 2.5Dt (with a pile length of 3Dt) increases the maximum lateral deflection by about 420%. Regarding the interaction between tunneling and group of piles, a positive group effect was observed with a significant reduction of the internal forces in rear piles. The maximum bending moment of the front piles was found to be higher than that of the rear piles by about 47%.

Soil is a complex material that shows differently in primary loading, unloading and reloading with stress-dependent stiffness. This general behavior was not possibly being accounted for in simple elastic perfectly plastic Mohr–Coulomb model which is often used to predict the behavior of soils. Thus, in the present study, the more advanced hardening soil model with small-strain stiffness (HSsmall) is used to model the non-linear stress–strain soil behavior. Moreover, unlike previous studies THAT are usually based on the assumption that the soil is homogeneous and using numerical methods by decoupled loadings under plane strain conditions; in this study, the pile responses have been exhaustively investigated in a two-layered soil system using a fully coupled 3D numerical analysis that takes into account the real interactions between tunneling and pile foundations. The paper presents a distinctive set of findings and insights that provide valuable guidance for the design and construction of shield tunnels passing through pile foundations.

The main function of the castellation process is making I-sections stiffer by increasing the height of web and supplying a higher moment capacity of primary axis than plain-webbed members of the same weight. In addition, it optimizes the use of heavy, costly constructional steel material and provides good services accessibility. The purpose of this study was to investigate the strength and buckling behavior of axially loaded castellated cruciform steel columns using finite element analysis. Although a significant body of research exists on the failure of different columns, there is no proper criterion introduced to determine the point of buckling in the equilibrium path of an imperfect column.

This paper considers a wide range of practical geometric dimensions and various end conditions using ANSYS software. Findings are reported for about 224 samples of castellated cruciform I-shaped sections, and a simplified approach to evaluate buckling capacity of castellated columns, using the slenderness-load curve, is developed. In addition, the axial compressive capacities of those steel sections are investigated numerically in the current study.

The results of nonlinear analyses of these columns revealed that the load-carrying capacity of castellated cruciform steel columns far outweighs and is more appropriate than that of the traditional cruciform steel columns. In the present paper, new geometric criteria have been introduced having the ability to cover different types of columns. It shows the critical load of columns in the range of elastic and inelastic behavior.

This study can provide a background for practical engineering applications and design specifications for steel structures with castellated sections. In the present paper, new geometric criteria have been introduced having the ability to cover different types of columns. It shows the critical load of columns showing both elastic and inelastic behavior. Because this method showed reliable performance, it can be used during experimental tests for detecting buckling point.

This study can provide background for practical engineering applications and design specifications for steel structures with castellated sections; also, a physical criterion has been defined for calculating the buckling load of real columns.

This paper aimed a fractional-order sliding mode-based lateral lane-change control method that was proposed to improve the path-tracking accuracy of vehicle lateral motion.

In this paper the vehicle presighting and kinematic models were established, and a new sliding mode control isokinetic convergence law was devised based on the fractional order calculus to make the front wheel turning angle approach the desired value quickly. On this basis, a fractional gradient descent algorithm was proposed to adjust the radial basis function (RBF) neuron parameter update rules to improve the compensation speed of the neural network.

The simulation results revealed that, compared to the traditional sliding mode control strategy, the designed controller eliminated the jitter of the sliding mode control, sped up the response of the controller, reduced the overshoot of the system parameters and facilitated accurate and fast tracking of the desired path when the vehicle changed lanes at low speeds.

This paper combines the idea of fractional order calculus with gradient descent algorithm, proposed a fractional-order gradient descent method applied to RBF neural network and fast adjustment the position and width of neurons.

Due to the enormous increase in economic development, structural steel material gives an advantage for the construction of stadiums, factories, bridges and cities building design. The purpose of this study is to investigate the behaviour of bending, buckling and torsion for I-beam steel section with and without web opening using non-linear finite element analysis.

The control model was simulated via LUSAS software with the four main parameters which included opening size, layout, shape and orientation. The analysis used a constant beam span which is 3.5 m while the edge distance from the centre of the opening to the edge of the beam is kept constant at 250 mm at each end.

The analysis results show that the optimum opening size obtained is 0.65 D while optimum layout of opening is Layout 1 with nine web openings. Under bending behaviour, steel section with octagon shapes of web opening shows the highest yield load, yield moment and thus highest structural efficiency as compared to other shapes of openings. Besides, square shape of web opening has the highest structural efficiency under buckling behaviour. The lower buckling load and buckling moment contribute to the higher structural efficiency.

Further, the square web opening with counter clockwise has the highest structural efficiency under torsion behaviour.

Under this heading are published regularly abstracts of Reports and Memoranda of the Aeronautical Research Council and Publications of other similar Research Bodies as issued.

This paper aims to investigate single pile and pile group responses due to deep braced excavation-induced soil movement in soft clay overlying dense sand. The analysis focuses first on the response of vertical single pile in terms of induced bending moment, lateral deflection, induced axial force, skin resistance distribution and pile settlement. To better understand the single pile behaviour, a parametric study was carried out. To provide further insights about the response of pile group system, different pile group configurations were considered.

Using the explicit finite element code PLAXIS 3 D, a full three-dimensional numerical analysis is carried out to investigate pile responses when performing an adjacent deep braced excavation. The numerical model was validated based on the results of a centrifuge test. The relevance of the 3 D model is also judged by comparison with the 2 D plane strain model using the PLAXIS 2 D code.

The results obtained allowed a thorough understanding of the pile response and the soil–pile–structure interactions phenomenon. The findings reveal that the deep excavation may cause appreciable bending moments, lateral deflections and axial forces in nearby piles. The parametric study showed that the pile responses are strongly influenced by the excavation depth, relative pile location, sand density, excavation support system and pile length. It also showed that the response of a pile within a group depends on its location in relation to the other piles of the pile group, its distance from the retaining wall and the number of piles in the group.

Unlike previous studies which investigated the problem in homogeneous geological context (sand or clay), in this paper, the pile response was thoroughly studied in a multi-layered soil using 3 D numerical simulation. To take into account the small-strain nonlinear behaviour of the soil, the Hardening soil model with small-strain stiffness was used in this analysis. For a preliminary design, this numerical study can serve as a practical basis for similar projects.

The design of cantilever pile walls (CPWs) presents several common challenges. These challenges include soil variability, groundwater conditions, complex loading conditions, construction considerations, structural integrity, uncertainties in design parameters and construction and monitoring costs. Accordingly, this paper is to provide a detailed literature review on the design criteria of CPWs, specifically in cohesionless soil. This study aims to present a comprehensive overview of the current state of knowledge in this area.

The paper uses a literature review approach to gather information on the design criteria of CPWs in cohesionless soil. It covers various aspects such as excavation support systems (ESSs), deformation behavior, design criteria, lateral earth pressure calculation theories, load distribution methods and conventional design approaches.

The review identifies and discusses common challenges associated with the design of CPWs in cohesionless soil. It highlights the uncertainties in determining load distribution and the potential for excessive wall deformations. The paper presents various approaches and methodologies proposed by researchers to address these challenges.

The paper contributes to the field of geotechnical engineering by providing a valuable resource for geotechnical engineers and researchers involved in the design and analysis of CPWs in cohesionless soil. It offers insights into the design criteria, challenges and potential solutions specific to CPWs in cohesionless soil, filling a gap in the existing knowledge base. The paper draws attention to the limitations of existing analytical methods that neglect the serviceability limit state and assume rigid plastic soil behavior, highlighting the need for improved design approaches in this context.

Piles often carry combination of axial and lateral. Currently, piles are designed separately for axial and lateral load. In the literature, few information is available on the influence of axial load on lateral behaviour of the pile. This paper aims to present the results of load deformation of a pile under pure lateral load and combined axial and lateral load.

The field load tests were carried out on four different pile diameters at two different bridge sites. Moreover, the paper addresses the numerical simulation of filed load test carried out on the pile under the combination of axial and horizontal load.

After field load tests and numerical simulation, it was found that the vertical load had a remarkable effect on the lateral load response of a pile. The lateral deflection of the pile was decreased about 25% under the effect of vertical load. In addition to this, the results from field and numerical simulation are quite comparable.

Typical field load tests were simulated numerically. This research adds a value in the areas of pile foundation subjected to vertical and lateral load particularly for structure such as transmission line tower and jetty.