scholarly journals Analysis of Load-Bearing Capacity of Initial lining in Tunnels

2021 ◽  
Vol 9 (VII) ◽  
pp. 3954-3960
Author(s):  
MD Waquar Alam
Keyword(s):  
Finite Element ◽  
Finite Element Model ◽  
Bearing Capacity ◽  
Element Model ◽  
Time Dependent ◽  
Load Bearing Capacity ◽  
Load Bearing ◽  
Full Face ◽  
Ground Condition ◽  
Drill And Blast

Large displacements during excavation are regularly observed in Squeezing ground condition and Rock-burst condition with high overburden. The expected displacement has to be estimated prior to excavation to provide enough allowance for the displacements. The support system need to be well-suited through the estimated imposed strains. As the estimated displacements and thus the strains in the support depend upon the load-bearing capacity of support. The ratio of uniaxial compressive strength of rock mass to maximal insitu stress determines tunnel integrity in the weak region.This ratio estimates the requirements of initial lining to control strain to a stipulated level. The elasto-plastic theory may deliver definitive forecasts providing the strength limitations of rock masses are identified accurately. With the help of empirical analysis, the development of displacements for diverse advance rates and supports can be concluded. As a consequence, a quantitative finite element model based on an advanced built-in model is designed to analyse the load-bearing efficiency of initial lining although taking into consideration the time-dependent and non-linear material behaviour of initial lining. The time-dependent excavation mechanism of the drill-and-blast approach for tunnels guided by full face excavation is considered in the finite element model. The material parameters for the initial lining were computed based on case studies- (A Chibro-Khodri Hydropower Tunnel).

Axial behaviour of slender concrete-filled steel tube square columns strengthened with square concrete-filled steel tube jackets

2019 ◽  
Vol 23 (6) ◽  
pp. 1074-1086 ◽  
Author(s):  
Tao Zhu ◽  
Hongjun Liang ◽  
Yiyan Lu ◽  
Weijie Li ◽  
Hong Zhang
Keyword(s):  
Finite Element ◽  
Finite Element Model ◽  
Bearing Capacity ◽  
Element Model ◽  
Steel Tube ◽  
Load Bearing Capacity ◽  
Load Bearing ◽  
Concrete Filled Steel Tube ◽  
Experimental Parameters ◽  
Modified Formula

This article investigates the behaviour of slender concrete-filled steel tube square columns strengthened by concrete-filled steel tube jacketing. The columns were realised by placing a square outer steel tube around the original slender concrete-filled steel tube column and pouring strengthening concrete into the gap between the inner and outer steel tubes. Three concrete-filled steel tube square columns and seven retrofitted columns ranging from 1200 to 2000 mm were tested to failure under axial compression. The experimental parameters included three length-to-width ( L/ B1) ratios, three width-to-thickness ( B1/ t1) ratios and three strengths of concrete jacket (C50-grade, C60-grade and C70-grade). Experimentally, the retrofitted columns failed in a similar manner to traditional slender concrete-filled steel tube columns. After strengthening, the retrofitted columns benefitted greatly from the component materials, with their load-bearing capacity and ductility notably enhanced. These enhancements were mainly brought about by sectional enlargement and good confinement of concrete. A finite element model was developed using ABAQUS to better understand the axial behaviour of the retrofitted specimens. A parametric study was conducted, with parameters including the length of the column, thickness of the outer steel tube, strength of the concrete jacket, yield strength of the outer steel tube, thickness of the inner steel tube and strength of the inner concrete. Furthermore, the finite element model was adopted to study the behaviour of rust-damaged and post-fire slender concrete-filled steel tube square columns strengthened by square concrete-filled steel tube jacketing. A modified formula was proposed to predict the load-bearing capacity of retrofitted specimens, and the numerical results agreed well with the experiments and the finite element results of undamaged, rust-damaged and post-fire specimens. It could be used as a reference for practical application.

scholarly journals Prediction of Load-Bearing Capacity of Composite Parts with Low-Velocity Impact Damage: Identification of Intra- and Inter-Ply Constitutive Models

2020 ◽  
Vol 1 (1) ◽  
pp. 59-78
Author(s):  
Aleksandr Cherniaev ◽  
Svetlana Pavlova ◽  
Aleksandr Pavlov ◽  
Valeriy Komarov
Keyword(s):  
Finite Element ◽  
Finite Element Model ◽  
Bearing Capacity ◽  
Damage Mechanics ◽  
Impact Damage ◽  
Element Model ◽  
Physical Parameters ◽  
Load Bearing Capacity ◽  
Load Bearing ◽  
Simulation Methodology

Assessments of residual load-carrying capacity are often conducted for composite structural components that have received impact damage. The availability of a verified simulation methodology can provide significant cost savings when such assessments are required. To support the development of a reliable and accurate simulation methodology, this study investigated the predictive capabilities of a stacked solid-shell finite element model of a cylindrical composite component with a damage mechanics-based description of the intra-ply material response and a cohesive contact model used for simulation of the inter-ply behavior. Identification of material properties for the model was conducted through mechanical characterization. Special attention was paid to understanding the influence of non-physical parameters of the intra- and inter-ply material models on predicting compressive failure load of damaged composite cylinders. Calibration of the model conducted using the response surface methodology allowed for identifying rational values of the non-physical parameters. The results of simulations with the identified and calibrated finite element model showed reasonable correlation with experimental data in terms of the predicted failure loads and post-impact and post-failure damage modes. The investigated modeling technique can be recommended for evaluating the residual load-bearing capacity of flat and curved composite parts with impact damage working under the action of compressive loads.

Finite Element Analysis of Lightweight Energy-Saving Composite Floor

2014 ◽  
Vol 665 ◽  
pp. 196-202
Author(s):  
Yi Qing Guo ◽  
Ping Zhou Cao
Keyword(s):  
Finite Element ◽  
Elastic Modulus ◽  
Bearing Capacity ◽  
Energy Saving ◽  
Element Model ◽  
Finite Element Models ◽  
Load Bearing Capacity ◽  
Element Analysis ◽  
Load Bearing ◽  
Thin Panel

In order to study the performance of lightweight energy-saving composite floor, the finite element models of composite floor were established, which was based on the composite floor specimens test research. The finite element models were verified rationally and correctly in the paper, through compared with the composite floor test results. The finite element model can be used to analyze the load-bearing capacity of composite floor. Various influencing factors of composite floor with simply supported end were analyzed, such as the span of self-tapping screw, the diameter of self-tapping screw, the strength of thin panel and the elastic modulus of thin panel, etc. The results show that the load-bearing capacity of composite floor increases with the increase of the number of self-tapping screw, the diameter of self-tapping screw, the strength of thin panel and the elastic modulus of thin panel, etc. The load-bearing capacity calculate formula of composite floor was proposed.

scholarly journals Experimental Study of Friction Resistance between Steel and Concrete in Prefabricated Composite Beam with High-Strength Frictional Bolt

2020 ◽  
Vol 2020 ◽  
pp. 1-13 ◽  
Author(s):  
Qi Guo ◽  
Qing-wei Chen ◽  
Ying Xing ◽  
Ya-ning Xu ◽  
Yi Zhu
Keyword(s):  
Finite Element ◽  
Friction Coefficient ◽  
Finite Element Model ◽  
Bearing Capacity ◽  
Concrete Strength ◽  
High Strength ◽  
Element Model ◽  
Construction Time ◽  
Friction Behavior ◽  
Friction Resistance

Prefabrication of composites beam reduces the construction time and makes them easily to be assembled, deconstructed, and partially repaired. The use of high-strength frictional bolt shear connectors can greatly enhance the sustainability of infrastructure. However, researches about the concrete-steel friction behavior are very limited. To provide a contribution to this area, 21 tests were conducted to measure the friction coefficient and slip stiffness with different concrete strength, steel strength, and surface treatment of steel. An effective finite element model was developed to investigate the ultimate bearing capacity and load-slip characteristics of bolt shear connection. The accuracy of the proposed finite element model is validated by the tests in this paper. The results demonstrate a positive correlation between concrete strength and friction coefficient and better performance of shot-blasted steel. It is also proved that high-strength frictional bolt has a 30% lower bearing capacity but better strength reserve and antiuplifting than the headed stud.

scholarly journals Nonlinear Time-Dependent Analysis of the Load-Bearing Capacity of a Single Permanent Shotcrete Lining at the Brenner Base Tunnel

2020 ◽  
Vol 30 (4) ◽  
pp. 475-483
Author(s):  
Matthias Neuner ◽  
Alexander Dummer ◽  
Magdalena Schreter ◽  
Günter Hofstetter ◽  
Tobias Cordes ◽  
...  
Keyword(s):  
Bearing Capacity ◽  
Time Dependent ◽  
Load Bearing Capacity ◽  
Load Bearing ◽  
Shotcrete Lining ◽  
Brenner Base Tunnel ◽  
Time Dependent Analysis

Finite-Element Simulations and Probabilistic Fracture Assessments of the Response of Alternate Rifling Geometries

2007 ◽  
Author(s):  
A. E. Segall ◽  
R. Carter
Keyword(s):  
Finite Element ◽  
Finite Element Model ◽  
Thermal Stresses ◽  
Rotational Symmetry ◽  
Element Model ◽  
Time Dependent ◽  
Uniform Heating ◽  
Thermal Pressure ◽  
Single Firing ◽  
Hoop Stresses

A 3-D finite-element model was used to simulate the severe and localized thermal/pressure transients and the resulting stresses experienced by a rifled ceramic-barrel with a steel outer-liner; the focus of the simulations was on the influence of non-traditional rifling geometries on the thermoelastic- and pressure-stresses generated during a single firing event. In order to minimize computational requirements, a twisted segment of the barrel length based on rotational symmetry was used. Using this simplification, the model utilized uniform heating and pressure across the ID surface via a time-dependent convective coefficient and pressure generated by the propellant gasses. Results indicated that the unique rifling geometries had only a limited influence on the maximum circumferential (hoop) stresses and temperatures when compared with more traditional rifling configurations because of the compressive thermal stresses developed at the heated (and rifled) surface.

scholarly journals PLASTIC CAPACITY OF BOLTED RHS FLANGE-PLATE JOINTS UNDER AXIAL TENSION

2016 ◽  
Vol 8 (3) ◽  
pp. 85-93
Author(s):  
Andrej Mudrov ◽  
Gintas Šaučiuvėnas ◽  
Antanas Sapalas ◽  
Ivar Talvik
Keyword(s):  
Finite Element ◽  
Bearing Capacity ◽  
Load Bearing Capacity ◽  
Finite Element Program ◽  
Load Bearing ◽  
Axial Tension ◽  
Flange Thickness ◽  
Element Program ◽  
Two Sides ◽  
Ansys Workbench

This article considers the calculation of load-bearing capacity of flange-plate joints with bolts along two sides of rectangular hollow sections (RHS) under axial tension. It provides a review and comparison of various calculation methodologies for establishing the load-bearing capacity of RHS flange-plate joints, such as suggested in EN 1993-1-8:2005 and STR 2.05.08:2005 as well as those proposed in different countries and by other authors. Common design principles and derived results for load-bearing capacity of flange-plate joints have been analysed and compared. Following the numerical modelling, which has been done using ANSYS Workbench finite element program, the derived results for load-bearing capacity have been compared with analytical load-bearing capacity results for flange-plate joints of the same structure. The analysis has focused on one type of flange-plate joints with bolts – both preloaded and non-preloaded – along two opposite sides of the tube, with the flange thickness of 15 mm and 25 mm.

FINITE ELEMENT ANALYSES ON CORRODED PONY TRUSS BRIDGE FOR REASONABLE MAINTENANCE

2020 ◽  
Vol 7 (2) ◽  
Author(s):  
Risa Fujinaga ◽  
Tatsumasa Kaita ◽  
Ryoko Koyama ◽  
Tsutomu Imai ◽  
Katashi Fujii
Keyword(s):  
Bearing Capacity ◽  
Ultimate Load ◽  
Plane Deformation ◽  
Element Model ◽  
Truss Structures ◽  
Load Bearing Capacity ◽  
Load Bearing ◽  
Out Of Plane ◽  
Pony Truss Bridge ◽  
Truss Bridge

The load bearing capacity of an existing corroded pony truss bridge, which is used for 100 years was estimated from FEM results for whole bridge model. The beam element model is to clarify that the influence of the residual out-of-plane deformation in main truss structures on the load bearing capacity from the viewpoint of whole bridge. Also, shell element model is to clarify that the influence of severe corrosion damages occurred in many structural members on the load bearing capacity as whole bridge. On the other hand, the influence of assumed support conditions in analytical models were discussed from the analytical results of both type of models, because it will be thought that the performance of shoes deteriorates gradually by long in-service period. The ultimate load bearing capacity was estimated by the critical live load magnification. From the analytical results, the residual out-of-plane deformation of main truss structures in this bridge had little influence on the ultimate load bearing capacity. Also, the ultimate load bearing capacity may decrease up to 20% due to aging deterioration of shoes including corrosion damages. In bridge maintenance, it should be paid attention on local severe corrosion damages on the structural member, which may occur higher secondary stress.

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