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Showing papers on "Bending moment published in 2022"


Journal ArticleDOI
TL;DR: In this paper, a large-scale 3D combined geomechanical model test is conducted to investigate the mechanical characteristics for linings of asymmetrically closely-spaced twin-tunnels constructed in sandy ground.

60 citations


Journal ArticleDOI
TL;DR: In this article , a large-scale 3D combined geomechanical model test is conducted to investigate the mechanical characteristics for linings of asymmetrically closely-spaced twin-tunnels constructed in sandy ground.

60 citations


Journal ArticleDOI
TL;DR: In this paper , a centrifuge model test was adopted to investigate the effects of new tunnelling on two existing overlying tunnels, and the volume loss produced by new tunnel excavation was modelled by an in-flight actuator system.

38 citations


Journal ArticleDOI
TL;DR: In this article , the influence of different loading heights and relative stiffness of pile and soil on the bending moment, soil resistance, and horizontal displacement of a single pile was studied in a test simulation.
Abstract: Laterally loaded piles are widely used in structural foundations under horizontal loads such as wave load, wind load, seismic load, and traffic load. Based on the complexity of pile-soil interaction, a test simulation of single pile through the indoor 1 g model test was conducted, in order to study the influence of different loading heights and relative stiffness of pile and soil on the bending moment, soil resistance, and horizontal displacement of pile. It is found that the shear modulus of soil from large to small is arranged as dry fine sand, dry coarse sand, saturated fine sand, and saturated coarse sand. The shear modulus of dry fine sand, dry coarse sand, and saturated fine sand are close under the same loading height and horizontal displacement of pile top, while the shear modulus of saturated coarse sand decreases sharply. Under the condition of water saturation, the particle size has a significant effect on the shear modulus of soil. The relative stiffness of pile soil is found to be the main influencing condition of pile horizontal displacement. Compared with the displacement and bending moment of the pile, the loading height has more influence on the soil resistance, and the main influence area is the soil resistance of the pile toe.

37 citations


Journal ArticleDOI
TL;DR: In this paper , a Gaidai-Fu-Xing structural reliability approach is proposed for multi-dimensional structural responses that have been simulated or measured over a long period to produce relatively large ergodic time series.
Abstract: Floating offshore wind turbines (FOWT) generate green renewable energy and are a vital part of the modern offshore wind energy industry. Robust predicting extreme offshore loads during FOWT operations is an important safety concern. Excessive structural bending moments may occur during certain sea conditions, posing an operational risk of structural damage. This paper uses the FAST code to analyze offshore wind turbine structural loads due to environmental loads acting on a specific FOWT under actual local environmental conditions. The work proposes a unique Gaidai-Fu-Xing structural reliability approach that is probably best suited for multi-dimensional structural responses that have been simulated or measured over a long period to produce relatively large ergodic time series. In the context of numerical simulation, unlike existing reliability approaches, the novel methodology does not need to re-start simulation again each time the system fails. As shown in this work, an accurate forecast of the probability of system failure can be made using measured structural response. Furthermore, traditional reliability techniques cannot effectively deal with large dimensionality systems and cross-correction across multiple dimensions. The paper aims to establish a state-of-the-art method for extracting essential information concerning extreme responses of the FOWT through simulated time-history data. Three key components of structural loads are analyzed, including the blade-root out-of-plane bending moment, tower fore-aft bending moment, and mooring line tension. The approach suggested in this study allows predicting failure probability efficiently for a non-linear multi-dimensional dynamic system as a whole.

24 citations


Journal ArticleDOI
TL;DR: In this paper , an anisotropic soil model developed by the Norwegian Geotechnical Institute (NGI) based on the Active-Direct shear-Passive concept (ADP) was adopted to conduct finite element (FE) analyses.

23 citations



Journal ArticleDOI
Jinxing Lai1
TL;DR: In this paper , a micro shield machine was invented to simulate the shield tunnelling process, and a series of physical scale model tests and 3-D nonlinear FE models were employed to investigate the pile group response with different minimum distance between pile group and the tunnel central line (Hm) in clay.

19 citations





Journal ArticleDOI
TL;DR: In this article , the effect of joint connections on acceleration and bending moment response of double box utility tunnels was investigated. But the effect on the joint connection was not evaluated. But it is suggested that the joint connections should be taken reasonably into consideration during design and construction for engineering practice.

Journal ArticleDOI
TL;DR: In this paper , a large-scale model test was conducted to explore the deformation and failure mechanism of tunnel with fault rupture, and the results showed that a prismoid-like 3D shear zone appeared within fault fracture zone.

Journal ArticleDOI
TL;DR: In this paper , a multivariate average conditional exceedance rate (ACER2D) method was used to estimate the extreme load responses of a 10MW semi-submersible type floating wind turbine (FWT).

Journal ArticleDOI
TL;DR: In this article , a parametric study was carried out to identify the influence of the following variables: positioning and shape of the tendons, initial prestressing force, and tendon and span lengths.

Journal ArticleDOI
TL;DR: In this article , the authors analyzed the behavior of a buried concrete pipe subjected to transverse seismic shake employing the linear elastic (LE) model, elasto-plastic Mohr-Coulomb (MC) model and hardening soil (Hs) model.
Abstract: No attention has been given in previous studies to understand the influence of the sophistication of the soil constitutive model on the response of buried concrete pipes subjected to transverse seismic effect. This research, therefore, has been conducted to address this gap in knowledge by analyzing the behavior of a buried concrete pipe subjected to transverse seismic shake employing the linear elastic (LE) model, elasto-plastic Mohr-Coulomb (MC) model, hardening soil (Hs) model, and hardening soil model with small strain stiffness (Hs small) to provide a benchmark study that helps the designers and the researchers to select the most suitable and less computationally demanding soil constitutive model. The cases of good and poor installation conditions have been considered in the analyses. In addition, numerous earthquake records have been used to allow the consideration of wide range of earthquake intensities to aid general conclusions. It was found that all of the considered constitutive models produce the same trend of the circumferential bending moment (BM) that is developed around the pipe. In general, the maximum BM produced using the LE and MC models is significantly lower than that produced using the Hs and Hs small models with one exception for the LE model for a predominant frequency of 0.66 Hz. Furthermore, the maximum BM produced using the LE and MC models is not sensitive to the increase of the peak ground acceleration (PGA). More importantly, the Hs and Hs small models produce almost similar results with a percentage difference ranges between 1% to 9%. In addition, the Hs and Hs small models show a decrease of the maximum BM as the predominant frequency rises and an increase of the maximum BM as the PGA rises.

Journal ArticleDOI
TL;DR: In this paper , the authors investigated the effects of double basement excavations on an existing floating pile in dry sand and found that double basements excavated simultaneously has limited effects on pile head settlement.

Journal ArticleDOI
TL;DR: In this article, the authors investigated the effects of double basement excavations on an existing floating pile in dry sand and found that double basements excavated simultaneously has limited effects on pile head settlement.

Journal ArticleDOI
TL;DR: In this article, a phase-field modeling method based on spectral decomposition is proposed to simulate the shield tunnel lining with mixed-mode cracks, which unifies the critical energy release rate and crack-driving strain energy.

Journal ArticleDOI
TL;DR: In this paper , the impact responses of the ship-offshore wind turbine jacket foundation system were investigated and the most dangerous impacting cases and vulnerable components were identified, and the effects of impact locations, collision angles and impact velocities on crashing responses, impact energy distributions and interactive deformation mechanisms were studied.

DOI
01 Jan 2022
TL;DR: In this paper, Wang and Penzien used two analytical solutions for the analysis of tunnel lining forces, constructed in soft to hard soil with various mechanical properties and constant shear strain, and found that the induced circular stress in the tunnel liner is decreased with increasing soil stiffness.
Abstract: In both urban and national frameworks, tunnels form vital components of the transport and utility systems. They are being constructed in densely populated urban zones and metro cities at an expanding rate to promote rising space and passage requirements. Occurrence of any sort of seismic activity in that particular region may cause damage of these infrastructures. Hence, a careful consideration of the impacts of seismic loadings on the analysis and design of tunnels is required as a part of hazard evaluation. Different closed form analytical approaches exist, such as methods given by Wang and Penzien for seismic analysis of shallow tunnels. Ovaling deformations occur when seismic waves propagate perpendicular to the axis of tunnel and are therefore, designed for the transverse direction. In this paper, these two analytical solutions are used for the analysis of tunnel lining forces, constructed in soft to hard soil with various mechanical properties and constant shear strain. Seismic analysis was carried out by means of selecting eight unique types of soil, very soft clay to highly dense sand. The study indicates a relative error in both analytical methods. It was found that the variations in thrust and bending moment are dependent on the flexibility ratio, thus, it is proposed that the stress distribution is to be considered for analysis and design of tunnels’ lining. It is also seen that the induced circular stress in the tunnel liner is decreased with increasing soil stiffness.

Journal ArticleDOI
TL;DR: In this paper , a 3D nonlinear finite element (FE) model validated by burst tests was developed to investigate the effect of bending moment and axial force on the burst capacity of corroded pipelines.

Journal ArticleDOI
TL;DR: In this paper , a large-scale disaster testing system was used to evaluate the effectiveness of polyurethane (PU) grouting in rehabilitating erosion voids in concrete pipes of intact, with an erosion void at the invert.

Journal ArticleDOI
TL;DR: In this paper , experimental and theoretical studies were carried out to assess the influence of the vertical mounting joint zone of the tank on the stress-strain state of the defect zone.
Abstract: In the study, experimental and theoretical studies were carried out to assess the influence of the vertical mounting joint zone of the tank on the stress-strain state of the defect zone. Thus, experimental tests of models of a tank wall fragment with an imperfection of the mounting joint evaluated the stress-strain state of the mounting joint zone and established the dependence of the stress concentration in the joint zone on the deflection, the width of the zone and the thickness of the tank wall. It is shown that with a 50 mm bending boom, the annular stresses increase by 1.3 times than with a 30 mm bending boom and the meridional stresses increase by 1.16 times. The same nature of the increase is observed with the stress concentration indicator. By numerical analysis of the stress-strain state of tanks with joint imperfections in the ANSYS medium, the stress-strain state of the tank is estimated for various values of the joint bending parameters ς and ξ. The dependences of the stress concentration coefficient on the geometric dimensions of the imperfection, radius and thickness of the tank wall are also obtained. From the results of calculating the stress concentration coefficient, with an increase in the dimensionless parameters ς and ξ, the values of the stress concentration coefficient Kσ increase by 1.35 times. As a result of the calculations, an interpolation polynomial (5), approximating the stress concentration coefficient Kσ, is obtained, which can be used to estimate the strength, durability and residual resource of the tank. In addition, the obtained results can be used to normalize the limiting dimensions of the imperfection of the joint and to establish the values of the coefficient, taking into account the peculiarities of the work of structures at stress concentrations.

Journal ArticleDOI
TL;DR: In this article, the results of dynamic centrifuge tests carried out considering varying sloping inclination angles for a liquefiable ground subjected to four successive earthquake shakings having an increasing amplitude of acceleration were presented.

Journal ArticleDOI
TL;DR: In this paper , an analytical model for calculating the additional response of the segmental lining under asymmetric thrusts was established, where the shield tunnel was simplified to a Timoshenko beam on Winkler's foundation.

Journal ArticleDOI
Anurag Sahare1
TL;DR: In this article , the results of dynamic centrifuge tests carried out considering varying sloping inclination angles for a liquefiable ground subjected to four successive earthquake shakings having an increasing amplitude of acceleration were presented.

Journal ArticleDOI
TL;DR: In this paper , the authors investigated the deformation behavior of an inclined TBM tunnel in the deep water-bearing sandstone and impermeable mudstone before and after aquifer drainage.

Journal ArticleDOI
TL;DR: An experimental and numerical study into the global buckling behavior of structural steel circular hollow section (CHS) beam-columns with normal and high strength steel grades is presented in this article.

Journal ArticleDOI
TL;DR: In this paper , a coupled vibration model of unsaturated soil-pile system subjected to Rayleigh waves is established on the basis that the pile cap is equivalent to a rigid mass block.
Abstract: Under the action of Rayleigh waves, pile head is easy to rotate with a concrete pile cap, and pure fixed‐head condition is rarely achieved, which is a common phenomenon for it usually occurs on the precast piles with insufficient anchorage. In addition, the propagation characteristics of Rayleigh wave have been changed significantly due to the existence of capillary pressure and the coupling between phases in unsaturated soil, which significantly affects the pile‐soil interaction. In order to study the above problems, a coupled vibration model of unsaturated soil–pile system subjected to Rayleigh waves is established on the basis that the pile cap is equivalent to a rigid mass block. Meanwhile, the soil constitution is simplified to linear‐elastic and small deformations are assumed to occur during the vibration phase of soil–pile system. Then, the horizontal dynamic response of a homogeneous free‐field unsaturated soil caused by propagating Rayleigh waves is obtained by using operator decomposition theory and variable separation method. The dynamic equilibrium equation of a pile is established by using the dynamic Winkler model and the Timoshenko beam theory, and the analytical solutions of the horizontal displacement, rotation angle, bending moment and shear force of pile body are derived according to the boundary conditions of flexible constraint of pile top. Based on the present solutions, the rationality of the proposed model is verified by comparing with the previous research results. Through parametric study, the influence of rotational stiffness and yield bending moment of pile top on the horizontal dynamic characteristics of Rayleigh waves induced pile is investigated in detailed. The analysis results can be utilized for the seismic design of pile foundation under Rayleigh waves.