Contents
Chapters
1 Introduction 1-3
2 Major Design Considerations 4-8
2.1 Introduction 4
2.2 Components of Pressed Steel Water Tanks 4
2.2.1 Tank Plates 4
2.2.2 Tank Covers 4
2.2.3 Tanks Partitions 4
2.2.4 Connection Cleats and Stays 5
2.2.5 Connection Bolts, Nuts and Washers 5
2.2.6 Jointing Material 5
2.2.7 Protective Treatment 5
2.2.8 Float Valve Chamber 6
2.3 Pressed Steel Water Tank Fittings 6
2.3.1 Standard Fittings 6
2.3.2 Optional Fittings 6
2.4 Methodology 6
2.4.1 Conceptualisation and Preparation of Design Basis 6
2.4.2 Design and Engineering of Pressed Steel Bolted and Profile Steel welded water tanks and supporting stagings 7
2.5 Salient Features for Design & Engineering 7
2.5.1 Rolled steel section framed Structure Model 7
2.5.2 RCC Foundation System 8
2.6 Other Design Considerations (both for RCC & Steel) 8
2.7 Code References 8
3 Design of Various Types of Water Tanks 9-25
3.1 Design of Pressed Steel Water tanks 9
3.1.1 Tank Sizes and Dimensions 9
3. 1.2 Typical Connection Detail of Pressed Steel Water Tanks 11
3.2 Design of Profile Steel Water Tank 14
3.2.1 Salient Features 14
3.2.2 Surface Protection 14
3.2.3 Tank Sizes and Dimensions 15
3.2.4 Profile Sheets used for Tank Wall & Roof 16
3.3 Design of Water Tank Supporting Towers 20
3.3.1 Design Approach 20
3.3.2 Analysis & Design Outcome 22
3.4 Surface Protection of Tank Plate Modules for Steel Water Tanks 24
3.4.1 Butyl Rubber Sheeting for water proofing of Water Tank 24
3.4. 1.1 Introduction 24
3.4. 1.2 Impermeability 24
3.4. 1.3 Weather resistance 24
3.4. 1.4 Temperature range 24
3.4. 1.5 Elasticity 24
3.4. 1.6 Durability 24
3.4. 1.7 Chemical resistance 24
3.4. 1.8 Water treatment 24
3.4. 1.9 Ease of repair 25
3.4.2 Melanoid Bituminois Black Paint & Galvalume for Steel Water Tanks 25
4 Calculation of Quantities and Cost Estimation 26-27
4.1 Quantities 26
4.2 Item Rates 26
4.3 Detail Cost Summary Table for both RCC and Steel option 27
5. Corrosion & leakage protection of steel water tanks 28-39
5.1 Introduction 28
5. 1. 1 Corrosion and Corrosion Protection 28
5. 1.2 Corrosion Mechanism 28
5.2 Forms gf Corrosion 29
5.3 Factors affecting Corrosion rates 30
5.3. 1 Time of Wetness 30
5.3.2 Atmospheric Pollution 30
5.3.3 Sulphates 30
5.3.4 Chlorides 30
5.4 Localised Corrosion 30
5.5 Corrosion Control 31
5.5.1 Effective Design 31
5.5.2 General Factors 31
5.5.3 Various Types of Corrosion Protection 31
5.5.3.1 Protective Coatings 31
5.5.3.2 Galvanic Corrosion
5.6 Performance of Galvanized Coatings 33
5.6. 1 Atmospheric Exposure 33
5.7 Corrosion Performance in Fresh Water 35
5.8 Corrosion Performance in Sea Water and Salt Spray 35
5.8. 1 Barrier Protection 35
5.8.2 Cathodic Protection 35
5.8.3 Corrosion-resistant Steels 36
5.9 Weld inspection on Water Tanks During Construction 5.9.1 Identifying Surface Defects . 36
5.9.2 Inspecting the Tank before Surface Preparation 36
5.9.3 Post-Application Inspection 37
5.10 Leakage in Steel Water Tanks 37
5.10.1 Method for Testing Tanks for Watertightness 38
5. 10. 1. 1 General 38
5.10. 1.2 Hydrostatic Leak Test 38
5.10. 1.3 Cyclical Test 38
6. Life Cycle Cost Analysis for Elevated Water tanks 40-51
6.1 Introduction 40
6.1.1 Objective of conceptualising an elevated water reservoir project 40
6.1.2 Identification of the project 41
6.1.3 Feasibility and option analyses 41
6.1.4 Economic analysis 42
6.2 Terminology of Life Cycle Cost Analysis 42
6.2.1 Initial & Future Expenses 43
6.2.2 Residual Value 43
6.2.3 Study Period 43
6.2.4 Real Discount Rate 44
6.2.5 Constant-Rupees 45
6.2.6 Present Value 45
6.3 Steps to Complete Life Cycle Cost Analysis 46
6.3.1 Initial Investment Cost 46
6.3.2 OperationCost 47
6.3.3 Maintenance & Repair Costs 47
6.3.4 Replacement Costs 48
6.3.5 Residual Value 48
6.3.6 Evaluation of Best Alternative 49
6.4 Assessment of Life Cycle Cost for elevated waterreservoir with staging 49
7 Conclusion
8 References 54
Appendix -A
Design of Aqua plate Steel Water Tank A1-A9
A.1 Introduction A1
A.2 Material Specification A1
A.3 Method of Construction A1
A.4 Painting of Exterior Tank Walls A3
A.5 Construction Sequence A5
Appendix- 8
Design of Aqua plate Steel Water Tank B1-B9
8.1 Introduction B1
8.2 Shape ofRCC Elevated Water Tank B1
8.3 Design procedure for an elevated RCC lntze tank B2