scholarly journals Application of Hyperstatic Reaction Method for Designing of Tunnel Permanent Lining, Part I: 2D Numerical Modelling

2016 ◽  
Vol 2 (6) ◽  
pp. 244-253 ◽  
Author(s):  
Rahim Hassani ◽  
Rouhollah Basirat
Keyword(s):  
Numerical Modelling ◽  
Bending Moment ◽  
Practical Method ◽  
Tunnel Lining ◽  
Earthquake Loading ◽  
Reaction Method ◽  
Simplified Approach ◽  
Design Earthquake ◽  
Hyperstatic Reaction Method

The increase of bored tunnels in the entire world has raised the question how to design the tunnel structure in an efficient way. This paper proposes a numerical approach to the Hyperstatic Reaction Method (HRM) for analysing permanent tunnel linings. The permanent tunnel lining is known as main structure of tunnel maintenance during the time. The HRM is one of the analysis methods for tunnel lining in long term. In this paper, two dimensional numerical modelling is performed by considering hyperstatic reaction concepts. Loading is done after the calculation of long term loads, and ground reaction is simulated by springs. Designing is done for Manjil-Rudabar freeway project, Tunnel No. 2. The numerical analyses were performed for Operational Design Earthquake (ODE) and Maximum Design Earthquake (MDE) loading conditions. A new simplified approach is used for considering the effect of earthquake loading on the tunnel lining. Then, an interaction diagram between axial force and bending moment used for investigating the capacity of tunnel lining. The thickness of tunnel lining and armature are calculated for three sections based on induced forces in tunnel lining. These forces were different in every section according to the load combinations, rock mechanics properties, lining properties, and overburden.  The numerical results showed that the forces in tunnel lining for MDE condition is approximately 50% more than ODE condition in earthquake loading. This numerical processing presented that the HRM is a proper, fast, and practical method for designing and analysing the tunnel lining.

scholarly journals Application of Hyperstatic Reaction Method for Designing of Tunnel Permanent Lining, Part II: 3D Numerical Modelling

2016 ◽  
Vol 2 (6) ◽  
pp. 254-261
Author(s):  
Rahim Hassani ◽  
Rouhollah Basirat
Keyword(s):  
Numerical Modelling ◽  
Dimensional Analysis ◽  
Three Dimensional ◽  
Bending Moment ◽  
Tunnel Lining ◽  
Reaction Method ◽  
Axial Forces ◽  
Road Tunnels ◽  
Design Earthquake ◽  
Hyperstatic Reaction Method

Underground structures often have abrupt changes in structural stiffness or ground conditions such as junctions of tunnels, tunnel portal in slopes, and niches in road tunnels. At these locations, stiffness differences may subject the structure to differential movements and generate stress concentrations. Because of adversity in these issues, they need a three dimensional analysis. This paper proposes a numerical approach to the hyperstatic reaction method (HRM) for three dimensional analysis of permanent tunnel linings. In this paper, three dimensional numerical modelling is performed by considering hyperstatic reaction concepts. Designing is done for Manjil-Rudabar freeway project, Tunnel No. 2. The numerical analyses performed for Operational Design Earthquake (ODE) and Maximum Design Earthquake (MDE) loading conditions. Then interaction diagram between axial force and bending moment used for investigating the capacity of tunnel lining. The numerical results show that although more axial forces are created in tunnel lining for ODE condition, but the points in the P-M diagrams are located in the furthest distance to the diagram border (tunnel supporting system); because of less bending moment in this condition. Therefore, the safety factor in ODE condition is more than MDE condition. This numerical processing presented that the HRM is a proper, fast, and practical method for tunnel designers.

Reliability of tunnel lining design using the Hyperstatic Reaction Method

2018 ◽  
Vol 77 ◽  
pp. 59-67 ◽  
Author(s):  
Henrique M. Kroetz ◽  
Ngoc Anh Do ◽  
Daniel Dias ◽  
André T. Beck
Keyword(s):  
Tunnel Lining ◽  
Reaction Method ◽  
Tunnel Lining Design ◽  
Hyperstatic Reaction Method

scholarly journals U-shaped tunnel lining design using the Hyperstatic Reaction Method – Influence of the invert

2020 ◽  
Vol 60 (3) ◽  
pp. 592-607
Author(s):  
Dianchun Du ◽  
Daniel Dias ◽  
Ngocanh Do ◽  
Tronghung Vo
Keyword(s):  
Tunnel Lining ◽  
Reaction Method ◽  
Tunnel Lining Design ◽  
Hyperstatic Reaction Method

Numerical Modelling and Experimental Measurement of Lifting Platform Construction for Car Relocation

2015 ◽  
Vol 732 ◽  
pp. 219-222
Author(s):  
Michal Petrů ◽  
Petr Lepšík ◽  
Ondřej Novák ◽  
Aleš Lufinka
Keyword(s):  
Numerical Modelling ◽  
Experimental Measurement ◽  
Production Line ◽  
Bending Moment ◽  
Dynamical Analysis ◽  
Experimental Measurements ◽  
Term Operation ◽  
Assessment Of Stress ◽  
Scissor Mechanism

Numerical modelling and experimental measurements led to the assessment of stress of structural nodes of scissor lifting platform, which is used for relocation of cars from a production line. It also led to optimization of producing process. Immediate load of scissor lifting platform by a car on stand causes additional bending moment that must be captured in a scissor mechanism. At the beginning the experimental measurements on the real lifting platform were made for obtaining of dependence of displacement, velocity and acceleration on time which was almost 1.5±0.1 g. Then dynamical analysis using a numerical method Runge Kutta 4th order of lifting platform were created. Model analysis showed that the initial immediate acceleration of lifting platform at start and immediate deceleration at stop lead to dynamic shocks. These dynamic shocks are due to long term operation dangerous because they permanently load not only pivots but also other parts – bearings and joining parts. A resonance may occur as well. In particular, dynamic shocks caused damage of structural nodes. Immediate load of scissor lifting platform by a car on stand causes additional bending moment. It is not appropriate in terms of long-term operation. Recommended load lifting platform should be symmetrical.

Long-term lahar reconstruction in Jamapa Gorge, Pico de Orizaba (Mexico) based on botanical evidence and numerical modelling

Landslides ◽  
2021 ◽  
Author(s):  
José Ernesto Figueroa-García ◽  
Osvaldo Franco-Ramos ◽  
José María Bodoque ◽  
Juan Antonio Ballesteros-Cánovas ◽  
Lorenzo Vázquez-Selem
Keyword(s):  
Numerical Modelling

Strength Performance of Steel Catenary Riser Using Short Term and Long Term Analysis Methodologies

2016 ◽  
Author(s):  
Feng Wang ◽  
Roger Burke ◽  
Anil Sablok ◽  
Kristoffer H. Aronsen ◽  
Oddgeir Dalane
Keyword(s):  
Bending Moment ◽  
Current Profile ◽  
Short Term ◽  
Sea State ◽  
Strength Performance ◽  
Steel Catenary Riser ◽  
Analysis Methodology ◽  
Riser Design ◽  
Term Analysis

Strength performance of a steel catenary riser tied back to a Spar is presented based on long term and short term analysis methodologies. The focus of the study is on response in the riser touch down zone, which is found to be the critical region based on short term analysis results. Short term riser response in design storms is computed based on multiple realizations of computed vessel motions with various return periods. Long term riser response is based on vessel motions for a set of 45,000 sea states, each lasting three hours. The metocean criteria for each sea state is computed based on fifty six years of hindcast wind and wave data. A randomly selected current profile is used in the long term riser analysis for each sea state. Weibull fitting is used to compute the extreme riser response from the response of the 45,000 sea states. Long term analysis results in the touch down zone, including maximum bending moment, minimum effective tension, and maximum utilization using DNV-OS-F201, are compared against those from the short term analysis. The comparison indicates that the short term analysis methodology normally followed in riser design is conservative compared to the more accurate, but computationally more expensive, long term analysis methods. The study also investigates the important role that current plays in the strength performance of the riser in the touch down zone.

Load Combination for Fatigue Analysis of Ship Structures

2004 ◽  
Author(s):  
Yung S. Shin ◽  
Booki Kim ◽  
Alexander J. Fyfe
Keyword(s):  
Bending Moment ◽  
Linear Summation ◽  
Load Combination ◽  
Longitudinal Stiffeners ◽  
Stress Components ◽  
Tank Pressure ◽  
Wave Induced ◽  
Vertical Bending Moment ◽  
Oil Tanker

A methodology for calculating the correlation factors to combine the long-term dynamic stress components of ship structure from various loads in seas is presented. The methodology is based on a theory of a stationary ergodic narrow-banded Gaussian process. The total combined stress in short-tem sea states is expressed by linear summation of the component stresses with the corresponding combination factors. This expression is proven to be mathematically exact when applied to a single random sea. The long-term total stress is similarly expressed by linear summation of component stresses with appropriate combination factors. The stress components considered here are due to wave-induced vertical bending moment, wave-induced horizontal bending moment, external wave pressure and internal tank pressure. For application, the stress combination factors are calculated for longitudinal stiffeners in cargo and ballast tanks of a crude oil tanker at midship section. It is found that the combination factors strongly depend on wave heading and period in the short-term sea states. It is also found that the combination factors are not sensitive to the selected probability of exceedance level of the stress in the long-term sense.

scholarly journals Autogenic versus allogenic controls on the evolution of a coupled fluvial megafan/mountainous catchment system: numerical modelling and comparison with the Lannemezan megafan system (Northern Pyrenees, France)

2016 ◽  
Author(s):  
Margaux Mouchené ◽  
Peter van der Beek ◽  
Sébastien Carretier ◽  
Frédéric Mouthereau
Keyword(s):  
Numerical Modelling ◽  
Temporal Variations ◽  
Tectonic Activity ◽  
Mountain Range ◽  
Stream Network ◽  
Mountainous Catchment ◽  
Isostatic Rebound ◽  
Base Level ◽  
Alluvial Terraces

Abstract. Alluvial megafans are sensitive recorders of landscape evolution, controlled by autogenic processes and allogenic forcing and influenced by the coupled dynamics of the fan with its mountainous catchment. The Lannemezan megafan in the northern Pyrenean foreland was abandoned by its mountainous feeder stream during the Quaternary and subsequently incised, leaving a flight of alluvial terraces along the stream network. We explore the relative roles of autogenic processes and external forcing in the building, abandonment and incision of a foreland megafan using numerical modelling and compare the results with the inferred evolution of the Lannemezan megafan. Autogenic processes are sufficient to explain the building of a megafan and the long-term entrenchment of its feeding river at time and space scales that match the Lannemezan setting. Climate, through temporal variations in precipitation rate, may have played a role in the episodic pattern of incision at a shorter time-scale. In contrast, base-level changes, tectonic activity in the mountain range or tilting of the foreland through flexural isostatic rebound appear unimportant.

scholarly journals Two decades of numerical modelling to understand long term fluvial archives: Advances and future perspectives

2017 ◽  
Vol 166 ◽  
pp. 177-187 ◽  
Author(s):  
A. Veldkamp ◽  
J.E.M. Baartman ◽  
T.J. Coulthard ◽  
D. Maddy ◽  
J.M. Schoorl ◽  
...  
Keyword(s):  
Numerical Modelling ◽  
Future Perspectives ◽  
Fluvial Archives
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