1st Edition

Foundations for Industrial Machines Handbook for Practising Engineers

By K.G. Bhatia Copyright 2009
    672 Pages
    by CRC Press

    The performance, safety and stability of machines depends largely on their design, manufacturing and interaction with environment. Machine foundations should be designed in such a way that the dynamic forces transmitted to the soil through the foundation, eliminating all potentially harmful forces. This handbook is designed primarily for the practising engineers engaged in design of machine foundations. It covers basic fundamentals for understanding and evaluating dynamic response of machine foundation systems with emphasis is on detailed dynamic analysis for response evaulation. Use of commercially available Finite Element packages, for analysis and design of the foundation, is recommended. Theory is supported by results from practice in the form of examples.

    1. Machines and Foundations

    • 1.1 An Overview
    • 1.2 Design Philosophy
    • 1.3 Machine Foundation System
    • 1.4 Machines
    • 1.5 Foundation
    • 1.5.1 Block Foundation
    • 1.5.2 Frame Foundation
    • 1.5.3 Tuning of Foundation
    • 1.5.4 Foundation Material
    • 1.5.5 Foundation Analysis and Design
    • 1.6 Soil
    • 1.7 Vibration Isolation
    • 1.8 Field Performance and Feedback

    PART – I: THEORY OF VIBRATION BASIC UNDERSTANDING WITH SPECIFIC APPLICATION TO MACHINE FOUNDATION DESIGN

    2. Single Degree of Freedom System

    • 2.1 Free Vibration
    • 2.1.1 Undamped System - SDOF Spring Mass System
    • 2.1.2 Damped System
    • 2.2 Forced Vibration
    • 2.2.1 Undamped System - Dynamic Force Externally Applied
    • 2.2.2 Damped System - Dynamic Force Externally applied
    • 2.2.3 Damped System - Dynamic Force Internally Generated
    • 2.2.4 Damped System - Dynamic Excitation Applied At Base
    • 2.2.5 Undamped System - Subjected to Impact Loads
    • 2.2.6 Undamped System - Subjected to Impulsive Loads
    • Example Problems

    3. Multi-Degree of Freedom Systems

    • 3.1 Two Degree of Freedom System - Free Vibration - Undamped
    • 3.1.1 Two Spring Mass System- Linear Springs
    • 3.1.2 A Rigid Block supported by Vertical and Translational Springs
    • 3.1.3 A Rigid Block Supported by Vertical and Rotational Springs
    • 3.1.4 A Rigid Block supported by Translational and Rotational Springs
    • 3.1.5 Multiple Spring Mass Systems connected by a massless Rigid Bar
    • 3.1.6 A Portal Frame supporting mass at Beam Center
    • 3.2 Two Degree of Freedom System - Forced Vibration
    • 3.2.1 Undamped Two Spring Mass System
    • 3.2.2 Undamped Two Spring Mass System- Subjected to Impact Load
    • 3.2.2 A Rigid Block supported by Translational & Rotational Springs
    • 3.2.4 Multiple Spring Mass Systems connected by a massless Rigid Bar
    • 3.2.5 A Portal Frame supporting mass at Beam Center
    • 3.3 Three Degree of Freedom System - Free Vibration
    • 3.3.1 Three spring mass system
    • 3.3.2 A Rigid Block supported by Vertical, Translational & Rotational Springs
    • 3.4 Three DOF System - Forced Vibration
    • 3.4.1 Three Spring Mass System subjected to Harmonic Excitation
    • 3.4.2 A Rigid Block supported by Vertical, Translational & Rotational Springs subjected to Harmonic Excitation
    • Example Problems

    4. Vibration Isolation

    • 4.1.1 Principle of Isolation
    • 4.1.2 Transmissibility Ratio
    • 4.1.3 Isolation Efficiency
    • 4.1.4 Isolation Requirements
    • 4.1.5 Selection of Isolators
    • Example Problems

    PART – II: DESIGN PARAMETERS

    5. Design Sub-grade Parameters

    • 5.1 Introduction
    • 5.2 Soil Aspects Influencing Soil Structure Interaction
    • 5.2.1 Energy Transfer Mechanism
    • 5.2.2 Soil Mass Participation in Vibration of Foundations
    • 5.2.3 Effect of Embedment of Foundation
    • 5.2.4 Applicability of Hook’s Law to Soil
    • 5.2.5 Reduction in Permissible Soil Stress
    • 5.2.6 Damping in Soil
    • 5.3 Dynamic Soil Parameters
    • 5.3.1 Dynamic Soil Modulus
    • 5.3.2 Coefficients of Subgrade Reaction
    • 5.4 Design Soil Parameters
    • 5.4.1 Variation with respect to static Stress or Overburden Pressure
    • 5.4.2 Variation with respect to Base Contact area of Foundation
    • 5.5 Equivalent Springs
    • 5.5.1 Foundation Supported Directly over Soil
    • 5.5.2 Foundation Supported over an Elastic Pad
    • 5.5.3 Foundation Supported on a Set of springs
    • 5.5.4 Foundation Supported over Piles
    • Example Problems

    6. Design Machine Parameters

    • 6.1 Parameters for Rotary Machines
    • 6.1.1 Dynamic Forces
    • 6.1.2 Transient Resonance
    • 6.1.3 Critical Speed of Rotors
    • 6.1.4 Rotor Bearing Supports
    • 6.1.5 Forces due to Emergency and Faulted Conditions
    • 6.1.6 Coupling of Machines
    • 6.2 Parameters for Reciprocating Machines
    • 6.2.1 Dynamic Forces
    • 6.2.2 Transient Response
    • 6.2.3 Forces due to Emergency and Faulted Conditions
    • 6.2.4 Coupling of Machines
    • 6.3 Parameters for Impact Machines
    • 6.3.1 Machines producing repeated Impacts - Forgs Hammers
    • 6.3.2 Machines producing Impulse/Pulse Loading
    • 6.4 Amplitudes of Vibration
    • Example Problems

    7. Design Foundation Parameters

    • 7.1 Foundation Type
    • 7.2 Foundation Material
    • 7.2.1 Concrete
    • 7.2.2 Reinforcement
    • 7.3 Foundation Eccentricity
    • 7.4 Foundation Tuning
    • 7.4.1 Under-tuned Foundation
    • 7.4.2 Over-tuned Foundation
    • 7.5 Foundation Stiffness and Mass Parameters
    • 7.6 Other Miscellaneous Effects
    • 7.7 Vibration Limits in Machine Foundation Design
    • 7.8 Block Foundation
    • 7.8.1 Foundation Sizing
    • 7.8.2 Foundation Stiffness
    • 7.8.3 Strength Design
    • 7.8.4 Minimum Reinforcement
    • 7.9 Frame Foundation
    • 7.9.1 Foundation Sizing
    • 7.9.2 Stiffness Parameters
    • 7.9.3 Strength Design
    • 7.9.4 Minimum Reinforcement

    PART - III: DESIGN OF FOUNDATIONS FOR REAL LIFE MACHINES

    8. Modelling and Analysis

    • 8.1 Manual Computational Method
    • 8.1.1 Block Foundation
    • 8.1.2 Frame Foundation
    • 8.2 Finite Element Method
    • 8.2.1 Mathematical Modeling
    • 8.2.2 Machine
    • 8.2.3 Foundation
    • 8.2.4 Soil
    • 8.2.5 Dynamic Forces
    • 8.2.6 Boundary Conditions
    • 8.2.7 Material Data
    • 8.2.8 Degree of Freedom In-compatibility
    • 8.3 Dynamic Analysis
    • 8.3.1 Free Vibration Response
    • 8.3.2 Forced Vibration Response
    • 8.4 Strength Analysis and Design
    • 8.4.1 Block Foundation
    • 8.4.2 Frame Foundation
    • Example Problems

    9. Foundations for Rotary Machines

    • 9.1 Design of Block Foundation
    • 9.1.1 Dynamic Analysis
    • 9.1.2 Amplitudes of Vibration
    • Design Example- Foundation for Low Speed Machine
    • 9.2 Design of Frame Foundation
    • 9.2.1 Dynamic Analysis
    • 9.2.2 Lateral Mode of Vibration
    • 9.2.3 Vertical Mode of Vibration
    • 9.2.4 Lateral Vibrations Coupled with Torsional Vibrations
    • Design Example- Foundation for Turbo Generator

    10. Foundation for Reciprocating Machines

    • 10.1 Design of Block Foundation
    • 10.1.1 Dynamic Analysis
    • 10.1.2 Amplitude of Vibration
    • Design Example- Foundation for a Reciprocating Engine
    • Design of Frame Foundation
    • Design Example- Foundation for a Reciprocating Compressor

    11. Foundation for Impact and Implusive Load Machines

    • 11.1 Hammer Foundation
    • 11.1.1 Foundation Sizing
    • 11.1.2 Dynamic Analysis
    • Design Example- Foundation for a Drop Hammer
    • 11.2 Foundation for Machines Producing Impulsive Loads
    • 11.2.1 Foundation Sizing
    • 11.2.2 Dynamic Analysis
    • Design Example- Machine Producing Implusive Loads Applied at Repeated Interval

    PART - IV: DESIGN OF FOUNDATIONS WITH VIBRATION ISOLATION SYSTEM

    12. Vibration Isolation System

    • 12.1 Vibration Isolation Design
    • 12.1.1 Sizing of Inertia Block
    • 12.1.2 Selection of Isolators
    • 12.1.3 Location of Isolators
    • 12.1.4 Dynamic Analysis
    • Design Example- Vibration isolation for a Fan Foundation
    • Design Example- Vibration isolation for a Crusher Foundation

    PART - V: CONSTRUCTION ASPECTS & CASE STUDIES

    13. Construction Aspects

    • 13.1 Construction Joints
    • 13.2 Embedded Parts
    • 13.3 Placing/Laying of Concrete
    • 13.4 Grouting

    14. Case Studies

    • 14.1 Introduction
    • 14.2 Case Studies
    • Example- High Vibrations of a Motor Compressor Unit
    • Example- 210 MW Turbo-Generator unit - High Vibration Problems
    • Example- Reciprocating Compressor on Isolation pads
    • Example- Vibration Isolation of FD Fan Foundation

     

    Biography

    Dr. Krishna Gopal Bhatia has been engaged for over 30 years in the design, testing and review of machine foundations for various industrial projects in petrochemical plants, refineries, power plants and other large facilities. Moreover, he conducted extensive tests on machine foundation models and prototypes, as well as multiple failure analysis studies on various types of machines in this period. He has been active in several big companies, such as Bharat Heavy Electricals, Engineers India Ltd. Moreover, he has fulfilled executive roles at a number of earthquake societies and research institutes. In this reference guide, the author presents practical data and a design philosophy for the improvement of the design of foundations to enhance machine performance by more comprehensive evaluation of site soil data, better understanding of machine data. In this volume, more sophisticated modelling techniques, analysis techniques, structural design processes and construction technologies are proposed, in combination with guidelines for a more intense collaboration between foundation designer and machine manufacturer.