A model test and numerical investigation on the shear deformation patterns of deep wall–soil–tunnel interaction

2006 ◽  
Vol 43 (12) ◽  
pp. 1306-1323 ◽  
Author(s):  
Yong-Joo Lee ◽  
Richard H Bassett
Keyword(s):  
Finite Element ◽  
Shear Deformation ◽  
Urban Areas ◽  
Shear Failure ◽  
Model Tests ◽  
Numerical Analyses ◽  
Laboratory Model ◽  
Failure Patterns ◽  
Physical Tests ◽  
Deformation Patterns

In congested urban areas, tunnel excavations have become necessary due to a lack of space. In many cases, such excavations are needed in areas adjacent to existing loaded piles. Therefore, a careful assessment of the wall–soil–tunnel interaction is required. These circumstances are relatively new, however, and only limited information is currently available. The complicated soil behaviour, particularly for the shear failure pattern between the wall and tunnel observed in both physical tests and numerical analyses, has not been clearly identified by other researchers. The authors have conducted laboratory model tests on an idealized granular medium using close-range photogrammetric techniques to measure detailed displacement patterns. The results have been compared with those from numerical analyses. This paper presents shear failure patterns for a number of geometries and shows good agreement between the physical tests and the finite element analyses.Key words: tunnel excavation, shear deformation patterns, wall–soil–tunnel interaction, model tests, photogrammetry, finite element analysis.

scholarly journals Finite-element block shear failure deformation-to-fracture failure analysis

2020 ◽  
Vol 47 (4) ◽  
pp. 418-427 ◽  
Author(s):  
K.K. Adewole ◽  
Oladejo O. Joy
Keyword(s):  
Finite Element ◽  
Shear Deformation ◽  
Shear Failure ◽  
Tensile Deformation ◽  
Pure Shear ◽  
Contact Point ◽  
Shear Capacity ◽  
Total Load ◽  
Contact Points ◽  
Block Shear

This paper presents the finite-element (FE) block shear failure (BSF) deformation-to-fracture analysis. FE analysis reveals the following: BSF begins with bolt – bolt hole contact point compressive yielding and not the tensile or shear yielding reported in the literature. BSF does not result from the combination of the gauge tensile plane tensile deformation and the shear plane pure shear deformation alone as reported in the literature and codes. BSF results from compressive deformation of the bolt – bolt hole contact points, tensile deformation of bolt hole portions not in contact with the bolts, gauge tensile plane and edge distance tensile plane deformations in combination with pure shear deformation and a combined shear and tensile bending deformation of the portions of the shear planes near to and remote from the bolt – bolt hole contact points, respectively. This study provides a better understanding of the BSF mechanism, BSF total load-bearing areas, and various resistances to deformation that contribute to the block shear capacity.

scholarly journals Seismic Performance of Reinforced Concrete Short Columns Subjected to Freeze–Thaw Cycles

2019 ◽  
Vol 9 (13) ◽  
pp. 2708 ◽  
Author(s):  
Yixin Zhang ◽  
Shansuo Zheng ◽  
Xianliang Rong ◽  
Liguo Dong ◽  
Hao Zheng
Keyword(s):  
Reinforced Concrete ◽  
Energy Dissipation ◽  
Shear Deformation ◽  
Seismic Performance ◽  
Shear Failure ◽  
Shear Capacity ◽  
Hysteretic Behavior ◽  
Freeze Thaw ◽  
Failure Patterns ◽  
Short Columns

Previous research shows that freeze–thaw cycles represent one of the most dangerous threats to reinforced concrete (RC) structures. However, there is almost no experimental data on the effects of freeze–thaw cycles on the seismic behavior of RC columns showing flexure-shear failure. In this study, three columns with the shear span-to-depth ratio of 2.5 were subjected to different numbers of freeze–thaw cycles (FTCs) and pseudo-static testing. The seismic performance indexes of the specimens were analyzed in terms of hysteretic behavior, skeleton curves, shear deformation, and energy dissipation. The test observations show that the failure patterns of the test columns altered from the flexure dominated to shear dominated, owing to the more severe deterioration in shear capacity induced by freeze–thaw attack than in flexure capacity. The test results also indicate that freeze–thaw cycles significantly decrease the ductility and energy dissipation of test columns, and they increase the contributions of shear deformation to the total deformation.

scholarly journals Analysis of model helical piles subjected to axial compression

2020 ◽  
Vol 72 (09) ◽  
pp. 759-769
Keyword(s):  
Axial Compression ◽  
Model Tests ◽  
Numerical Analyses ◽  
Design Parameters ◽  
Laboratory Model ◽  
Good Correspondence ◽  
Plate Spacing ◽  
Plate Number ◽  
Helical Piles ◽  
Theoretical Results

An investigation into axial compression capacity of single helical piles placed in dry sand through laboratory model tests and numerical analyses is presented. The compressive bearing capacities were compared with existing theoretical results given in the literature. Laboratory model tests were performed to determine some design parameters of helical piles such as the plate number, plate diameter, and plate spacing. A good correspondence between experimental, numerical, and theoretical results was established.

Numerical and model studies of strip footing supported by a reinforced granular fill - soft soil system

1999 ◽  
Vol 36 (5) ◽  
pp. 793-806 ◽  
Author(s):  
K M Lee ◽  
V R Manjunath ◽  
D M Dewaikar
Keyword(s):  
Finite Element ◽  
Finite Element Model ◽  
Bearing Capacity ◽  
Soft Soil ◽  
Element Model ◽  
Model Tests ◽  
Laboratory Model ◽  
Soil System ◽  
Granular Fill ◽  
The Finite Element Model

Laboratory model tests have been carried out using a rigid strip footing supported on dense sand overlying soft clay with and without a layer of geotextile reinforcement at the interface. The study aimed at determining the effect of geotextile reinforcement and the thickness of a sand layer on the ultimate bearing capacity and settlement characteristics of the footing resting on a granular fill - soft soil system. It was found that the bearing capacity increases with an increase in the ratio of sand thickness to footing width until it reaches a critical value, which can be considered as the optimum limit of improvement of the bearing capacity of the layered soil. The installation of a geotextile reinforcement at the interface resulted in an appreciable increase in bearing capacity and decrease in settlement of the footing. The optimum thickness of the sand layer for a geotextile-reinforced foundation was found to be 0.8 times the width of the footing, which was significantly lower than that of an unreinforced foundation. The results of the laboratory model tests were validated by a comparison with the results of a finite element analysis. The results obtained using the finite element model compared well with data obtained from the laboratory tests. Additional parametric study was carried out by the finite element model to supplement the results of the laboratory model tests. Design recommendations are given based on the results of the finite element model and laboratory model studies for a rigid footing supported on a reinforced granular fill - soft soil system. Key words: model tests, footing, bearing capacity, granular fill, clays, finite elements, geotextiles.

Finite element bending analysis of symmetric and non-symmetric functionally graded sandwich beams using a novel parabolic shear deformation theory

2021 ◽  
pp. 146442072110050
Author(s):  
Mohamed-Ouejdi Belarbi ◽  
Abdelhak Khechai ◽  
Aicha Bessaim ◽  
Mohammed-Sid-Ahmed Houari ◽  
Aman Garg ◽  
...  
Keyword(s):  
Finite Element ◽  
Finite Element Model ◽  
Shear Deformation ◽  
Transverse Shear ◽  
Deformation Theory ◽  
Shear Deformation Theory ◽  
Element Model ◽  
Beam Element ◽  
Functionally Graded ◽  
Sandwich Beams

In this paper, the bending behavior of functionally graded single-layered, symmetric and non-symmetric sandwich beams is investigated according to a new higher order shear deformation theory. Based on this theory, a novel parabolic shear deformation function is developed and applied to investigate the bending response of sandwich beams with homogeneous hardcore and softcore. The present theory provides an accurate parabolic distribution of transverse shear stress across the thickness and satisfies the zero traction boundary conditions on the top and bottom surfaces of the functionally graded sandwich beam without using any shear correction factors. The governing equations derived herein are solved by employing the finite element method using a two-node beam element, developed for this purpose. The material properties of functionally graded sandwich beams are graded through the thickness according to the power-law distribution. The predictive capability of the proposed finite element model is demonstrated through illustrative examples. Four types of beam support, i.e. simply-simply, clamped-free, clamped–clamped, and clamped-simply, are used to study how the beam deflection and both axial and transverse shear stresses are affected by the variation of volume fraction index and beam length-to-height ratio. Results of the numerical analysis have been reported and compared with those available in the open literature to evaluate the accuracy and robustness of the proposed finite element model. The comparisons with other higher order shear deformation theories verify that the proposed beam element is accurate, presents fast rate of convergence to the reference results and it is also valid for both thin and thick functionally graded sandwich beams. Further, some new results are reported in the current study, which will serve as a benchmark for future research.

Beam finite element for thin-walled box girders considering shear lag and shear deformation effects

2021 ◽  
Vol 233 ◽  
pp. 111867
Author(s):  
Xiayuan Li ◽  
Shui Wan ◽  
Yuanhai Zhang ◽  
Maoding Zhou ◽  
Yilung Mo
Keyword(s):  
Finite Element ◽  
Shear Deformation ◽  
Shear Lag ◽  
Box Girders ◽  
Thin Walled

Nonlocal finite element model for the bending and buckling analysis of functionally graded nanobeams using a novel shear deformation theory

2021 ◽  
Vol 264 ◽  
pp. 113712 ◽  
Author(s):  
Mohamed-Ouejdi Belarbi ◽  
Mohammed-Sid-Ahmed Houari ◽  
Ahmed Amine Daikh ◽  
Aman Garg ◽  
Tarek Merzouki ◽  
...  
Keyword(s):  
Finite Element ◽  
Finite Element Model ◽  
Shear Deformation ◽  
Deformation Theory ◽  
Shear Deformation Theory ◽  
Element Model ◽  
Buckling Analysis ◽  
Functionally Graded

Flexural Vibration of Prestressed Concrete Bridges with Corrugated Steel Webs

2017 ◽  
Vol 17 (02) ◽  
pp. 1750023 ◽  
Author(s):  
Xia-Chun Chen ◽  
Zhen-Hu Li ◽  
Francis T. K. Au ◽  
Rui-Juan Jiang
Keyword(s):  
Finite Element ◽  
Shear Deformation ◽  
Prestressed Concrete ◽  
Natural Frequencies ◽  
Sandwich Beam ◽  
Flexural Vibration ◽  
Concrete Bridges ◽  
Mode Shapes ◽  
Beam Model ◽  
Prestressed Concrete Bridges

Prestressed concrete bridges with corrugated steel webs have emerged as a new form of steel-concrete composite bridges with remarkable advantages compared with the traditional ones. However, the assumption that plane sections remain plane may no longer be valid for such bridges due to the different behavior of the constituents. The sandwich beam theory is extended to predict the flexural vibration behavior of this type of bridges considering the presence of diaphragms, external prestressing tendons and interaction between the web shear deformation and flange local bending. To this end, a [Formula: see text] beam finite element is formulated. The proposed theory and finite element model are verified both numerically and experimentally. A comparison between the analyses based on the sandwich beam model and on the classical Euler–Bernoulli and Timoshenko models reveals the following findings. First of all, the extended sandwich beam model is applicable to the flexural vibration analysis of the bridges considered. By letting [Formula: see text] denote the square root of the ratio of equivalent shear rigidity to the flange local flexural rigidity, and L the span length, the combined parameter [Formula: see text] appears to be more suitable for considering the diaphragm effect and the interaction between the shear deformation and flange local bending. The diaphragms have significant effect on the flexural natural frequencies and mode shapes only when the [Formula: see text] value of the bridge falls below a certain limit. For a bridge with an [Formula: see text] value over a certain limit, the flexural natural frequencies and mode shapes obtained from the sandwich beam model and the classical Euler–Bernoulli and Timoshenko models tend to be the same. In such cases, either of the classical beam theories may be used.

Sign in / Sign up

Export Citation Format

Share Document