Table of Contents I
TABLE OF CONTENTS
Table of figures 1
List of Tables 3
Chapter 1 ANALYSIS OF INDUSTRIAL PLANT
1.1. Introduction 5
1.2. Definition of the problem 5
1.3. Structural classification 7
1.4. Earthquake induced failures of critical equipment in process plants 9
1.5. Industrial Ilva plant, Taranto 10
1.6. Aim of thesis 11
Chapter 2 CASE STUDY: HYDRATED LIME SILOS
2.1. Introduction 13
2.2. Elevated silo structure geometry 13
2.3 Material handling system and sequence 25
Chapter 3 MODELLIG IN INFOCAD AND LINEAR ANALYSES
3.1. Introduction 26
3.2. InfoCAD Model 26
3.2.1. Introduction to InfoCAD Software 26
3.2.2. Modelling approach 27
3.3. Loading on elevated silos 29
3.3.1. Introduction to Filling load in silo 29
3.3.2. Filling load in silo according to EN 1991-4-1 29
3.3.3. Filling loads on vertical walls for Intermediate slenderness silos 35
3.3.4. Filling load on Silo Hopper 38
3.3.5. Filling load on Shallow Hopper 39
3.4. Wind Load according to EN 1991-1-4 43
3.4.1. Basic for calculation 43
3.4.2. Basic values 43
3.4.3. Mean wind 44
3.4.4. Terrain roughness 45
3.4.5. Peak velocity pressure 46
3.4.6. Wind pressure on surfaces 47
3.5. Permanent Load 49
3.6. Imposed Load 49
3.7. Earthquake Load according to EN 1998-4 50
3.8. Taranto Elastic Response Spectrum 53
3.9. Behaviour factor 60
3.10. Combination of the actions 60
3.11. Linear Static analyses 61
3.12. Lateral Force Method 63
3.13. Modal response spectrum analysis 64
Table of Contents II
Chapter 4 MODELLIG TECHNIQUES ON ABAQUS
4.1. ABAQUS Software Package 68
4.2. Modelling approach 70
4.2.1. Creating the parts and defining model geometry 70
4.2.2. Types of elements 72
4.2.3. Meshing type 74
4.2.4. Bulk material 75
4.2.5. Natural frequency extraction 75
4.3. Non- linear behaviour of structures 78
4.3.1. Non-linear material– Strain Curve Model 78
4.3.2. Non-Linear Geometry Analyses 80
4.4. Imperfections 81
4.5. Analysis of steel braces with drawing imperfections 82
Chapter 5 PUSHOVER ANALYSIS
5.1. Background 88
5.2. Pushover analysis on the whole model 88
5.3. Pushover analysis on the Semplified model 91
5.3.1. Pushover analysis with nonlinear springs 93
5.3.2. Comparison of results between two models 96
5.4. N2 method 97
5.4.1. Seismic demand in Acceleration-displacement format 97
5.4.2. Pushover analysis 99
5.4.3. Equivalent SDOF model and capacity diagram 99
5.4.4. Seismic demand for the equivalent SDOF system 101
5.4.5. Target displacement of MDOF system 102
5.5. Limit States 102
5.5.1. Serviceability Limit State 103
5.5.2. Ultimate Limit State 103
5.5.3. Verification 104
Chapter 6 INCREMENTAL DYNAMIC ANALYSIS
6.1. Background 107
6.2. Performing IDA on Abaqus 108
6.3. Results 111
6.4. Assessment of behaviour factor 114