Foundations for industrial machines handbook for practising engineers, rotary machines, reciprocating machines, impact machines, vibration isolation system d CAD publishe

Part II caters to Design Parameters • Chapter 5 provides reasonable coverage to Soil Dynamics and evaluation of Design Soil Parameters as applied to Machine Foundation Design.. 5 De

Handbook for Practising Engineers

FOR INDUSTRIAL MACHINES

Handbook for Practising Engineers

K.G BHATIA

Foundations for Industrial Machines

First Edition 2008

While every effort is made to publish error-free information in this handbook, the author makes no representations or warranties of any kind, express or implied, about the completeness, accuracy, reliability, of the information, guidelines, methodologies or related graphics contained in the handbook, for any purpose Any reliance placed on such information is therefore strictly at one's own risk, unless that information is duly consulted and verified with the author, and subsequently confirmed in writing In no event will the author be liable for any loss or damage including without limitation, indirect or consequential loss or damage, or any loss or 'damage whatsoever arising from loss of data or profits, arising out of, or in connection with, the use of this handbook

Copyright © 2008 by D-CAD Publishers

All rights reserved This material may not be published, broadcast, rewritten or redistributed in whole or part without the express written permission of the author The book may contain copyrighted material, trademarks and other proprietary information, including, but not limited to, text, graphics, and users shall not publish and distribute such material (in whole or in part) and/or

to incorporate it in other works in any form, media or technology now known or hereafter developed

My parents

who, in spite of sufferings on account of partition, struggled hard and devoted their active life in upbringing me and my siblings

In expression of my gratitude to

My brother Shri MG Bhatia, who sacrificed his career

in support of my studies

Dedicated to

My wife Manjufor her constant encouragement and support

throughout the tenure of writing of this handbook

Organisations of Excellencefor Wok Experience

Bharat Heavy Electricals Limited

New Delhi

Engineers India Limited

New Delhi

Institutions of Excellence in Learning

Indian Institute o/Technology

New Delhi, India

International Institute o/Seismology

& Earthquake Engineering

The author has been engaged in designing, testing and review of machine foundations for various industrial projects viz Petrochemicals, Refineries, Power plants etc for the last about three decades

The handbook is written primarily for practising engineers as well as for students

at Post Graduate level Handbook shares author's long experience on the subject and focuses on the improvements needed in the design process with the sole objective of making practising engineers physically understand and feel the dynamics of machine foundation system

The handbook covers basic fundamentals necessary for understanding and evaluating dynamic response of machine foundation system The author has also conducted extensive tests on machine foundation models as well as on prototypes For over two decades, the author has been associated with Failure Analysis Studies on various types of machines

Observations from all the above studies suggest need for improvement in the design o/foundationsfor better performance of machines These include:

b) Better understanding of Machine Data and its use infoundation design

iii) Improvement in Structural Design process, and

It is the author's concerned observation that in most of the cases, due recognition

to Machine, Foundation and Soil data is lacking More often than not, machine data as well as soil data is treated as black box and used in the design without its

proper understanding A better interaction between foundation designer and machine manufacturer would definitely improve the foundation performance and thereby machine performance Over the years, author has observed that such interactions are lacking It is the author's concerned opinion that such an interaction is not only desirable but essential too

It is anticipated that this handbook shall serve as a Reference Book The author

is confident that it shall bridge the knowledge gap and shall be beneficial to the practising engineers, students, academicians/researchers as well to the industry The text is divided in to 5 Parts

Part I takes care of Theoretica( Aspects

• An overview providing basic familiarization with the subject is covered

in Chapter 1

• Necessary understanding of Theory of Vibration with specific application

Chapter 4 caters to Basic Theory of Vibration Isolation

Part II caters to Design Parameters

• Chapter 5 provides reasonable coverage to Soil Dynamics and

evaluation of Design Soil Parameters as applied to Machine Foundation Design

• Desired emphasis has been given to Design Machine Parameters

Translation of Machine Data to Design Data is given in Chapter 6

• Chapter 7 is attributed to Design Foundation Parameters It covers all

those aspects related to foundation that play vital role in computing Dynamic Response

Part III deals with design of Foundations for Real Life Machines

Analysis All possible aspects of modeling related to design of foundation have adequately been covered

.• Chapter 9, 10 & 11 cover Design of Foundation for real life Rotary Machines, Reciprocating Machines and Impact Type Machines respectively

Part IV caters to Design of Foundations with Vibration Isolation System

• A good amount of emphasis is given to Vibration Isolation of the Foundations Design of Foundations with Isolation Devices is covered in Chapter 12

Part V caters to Construction Aspects and Case Studies related to machine foundation

About the Handbook ix

1.6 Soil

1.7 Vibration Isolation

1.8 Field Performance and Feedback

PART-I THEORY OF VIBRATION

I-II

1-12 1-12

BASIC UNDERSTANDING WITH SPECIFIC APPLICATION

TO MACHINE FOUNDATION DESIGN

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

3.1 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

2-3 2-4 2-4 2-28 2-37 2-38 2-46 2-55 2-59 2-63 2-65

2-71

3-3 3-4 3-5 3-11 3-14

3.1.4 A Rigid Block supported by Translational and Rotational Springs 3-17

3.1.5 MUltiple Spring Mass Systems connected by a massless Rigid Bar 3-29

3.1.6 A Portal Frame supporting mass at Beam Center 3-34

3.2 Two Degree of Freedom System - Forced Vibration 3-37

3.2.3 A Rigid Block supported by Translational & Rotational Springs 3-51

3.2.4 Multiple Spring Mass Systems connected by a massless Rigid Bar 3-67

3.2.5 A Portal Frame supporting mass at Beam Center 3-71

3.3 Three Degree of Freedom System - Free Vibration 3-73

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

3-90

4-3 4-3 4-3 4-5 4-8 4-9

4-10

5 Design Sub-grade Parameters 5-3

5.2 Soil Aspects Influencing Soil Structure Interaction 5-3

5.2.2 Soil Mass Participation in Vibration of Foundations 5-6

5.4.1 Variation with respect to Static Stress or Overburden Pressure 5-22 5.4.2 Variation with respect to Base Contact Area of Foundation 5-23

5.5.1 Foundation Supported directly over soil 5-23 5.5.2 Foundation Supported over an Elastic Pad 5-28 5.5.3 Foundation Supported on a Set of springs 5-32

6.1.5 Forces Due To Emergency and Faulted Conditions 6-12

6.3.1 Machines producing repeated Impacts- Forge Hammers 6-20

7.7 Vibration Limits in Machine Foundation DeSign 7-10

9 Foundations for Rotary Machines 9-3

Design Example - Foundation for Low Speed Machine 9-16

9.2.4 Lateral Vibrations Coupled with Torsional Vibrations 9-57

Design Example - Foundation for Turbo Generator 9-62

Design Example - Foundation for A Reciprocating Engine 10-8

10.2 Design of Frame Foundation

Design Example - Foundation for a Reciprocating Compressor 10-26

11 Foundations for Impact and Impulsive Load Machines 11-3

Design Example - Foundation for a Drop hammer

11.2 Foundations for Machines Producing Impulsive Loads

11.2.1 Foundation Sizing

11.2.2 Dynamic Analysis

ll-Il

11-19 11-5 11-6

Design Example - Machine Producing Impulsive Loads Applied at Repeated

PART-IV DESIGN OF FOUNDATIONS

WITH VIBRATION ISOLATION SYSTEM

12 Vibration Isolation System

12.1 Vibration Isolation Design

12.1.1 Sizing of Sizing of Inertia Block

12.1.2 Selection ofIsolators

12.1.3 Location ofIsolators

12.1.4 Dynamic Analysis

12-3 12-3 12-3 12-4 12-4 12-4

Design Example - Vibration isolation for a Fan Foundation 12-7

Design Example - Vibration isolation of a Crusher Foundation 12-18

PART-V

14-3

14-6 Example - 210 MW Turbo-Generator unit -High Vibration Problems 14-7

Example - Reciprocating Compressor on Isolation pads

Example - Vibration Isolation of FD Fan Foundation

xxii xxiv xxvi xxviii

I am grateful to the following persons, who in one form or the other have contributed to the writing

• Prof A S Arya, Prof Emeritus lIT Roorkee, for guidance & encouragement at various stages

• Late Prof Jaikrishna for his guidance and advice throughout my association with him

• Prof AR Chandrasekaran, Prof (Retd.) lIT Roorkee for critical review, discussions and guidance at all stages of the handbook

• Mr K.P Mathur, Executive Director (Retd), BHEL for his motivation, encouragement and open forum discussions on various field problems and their solutions throughout my association with him

• Prof O.K Paul of lIT Roorkee for discussions on various technical issues from time to time

• Prof P K Swamee of lIT Roorkee for review & suggestions at various stages of the handbook

• Dr R K Goel of CBRI Roorkee for his valuable suggestions regarding publication of the handbook

• Prof Ramji Agrawal, IT BHU for his comments and critical review at various stages of the handbook

• Dr S P Singh, my friend at US, for his review, comments and suggestions at very initial stage

• Mr S K Goyal, my colleague at BHEL for discussions on field related technical issues

• Mr V Seshu Kumar for his support at various stages all through the writing of the book

• Mr Aashish and Ms Anu, my son & daughter-in-law, for their help in Modeling and Analysis

of various engineering problems at all stages of bringing out this handbook

• Mr Amit Bhatia and Ms Shilpa Bhatia, my son & daughter-in-law for providing total hardware support, editing, formatting and web-site designing and updating from time to time

• Mr C K Mohansastry, Executive Director (Retd), BHEL for his encouragement

• Mr Ramesh Pandey for his help in converting all the figures to Corel-Draw

• Mrs Manju Bhatia, my wife for her patience, moral support and encouragement throughout the tenure of the book without which it would not have been possible to complete the task

K G Bhatia

Improvement in manufacturing technology has provided machines of higher ratings with better tolerances and controIIed behaviour The increased dependence of society provides no room for failure and demands equipment and systems with higher performance reliability

Each and every machine does require detailed vibration analysis providing insight in to the dynamic behaviour of machine, foundation and their components Complete knowledge of machine excitation forces and associated frequencies, knowledge of load transfer mechanism from the machine to the foundation and foundation to soil is a must for correct evaluation of machine performance Thus for a technicaIIy correct and economical solution, it calls for that the designer must have a fairly good knowledge of Dynamic Soil Parameters, Dynamic Foundation Parameters

as weII as Dynamic Machine Parameters A close co-operation between manufacturer and the foundation designer is therefore a must Development of analytical procedures backed by field monitoring, for evaluating dynamic response, is the need of the day

It is fortunate that Dr K G Bhatia, a person of eminence, who is not only a well known research scientist in the field of Structural Dynamics but also l!I1 expert in the profession of Machine Poundation Design, Seismic Qualification of MachinetY, Failure Analysis, Weight Optimization etc, has undertaken the challenging task to bring out this Handbook on Foundation for Industrial Machines With his initial experience with Mis Engineers India Limited for about 4 years and his

association with MIs Bharat Heavy Electrical Limited for about 24 years, Dr Bhatia has carried out machine foundation design for many projects and has also conducted field studies on many machines and their foundations

It is this rich experience which Dr Bhatia has compiled and brought out in form of a Hand Book

He has touched all related aspects required for machine foundation design including Vibration Isolation System Starting with basic fundamentals of vibration analysis, he has given due coverage to analytical aspects, modeling aspects, design aspects and also included foundation design for real life machines backed up by field measurements based on his own experience and study

On behalf of the engineering community and on my own behalf, I wish to extend my hearty congratulations to Dr Bhatia for having brought out this excellent Handbook It is earnestly hoped that the book will be found useful by not only practising engineers but also by students, researchers and academicians

KP Mathur

(Formerly) Executive Director Project Engineering Management Bharat Heavy Electricals Ltd,

New Delhi, India

This handbook reflects collection of author's works in analysis, design and field investigations during last about 30 years The book, designed primarily for the practising engineers engaged in design of machine foundation, also provides a platform to students at Post Graduate level for developing professional skill in attaining desired proficiency in designing Foundations for Industrial Machines Reference to problems, made at various stages, is for the real field problems Emphasis, throughout, has been laid on applied analysis and design so as to provide deeper understanding to the reader about the physical understanding of the Dynamic Behaviour of Machine Foundation system The text has been so arranged so as to provide an insight to the reader regarding the need for various design stages to complete the task

The performance, safety and stability of machines depend largely on their design, manufacturing and interaction with environment In principle, machine foundations should be designed such that the dynamic forces of machines are transmitted to the soil through the-fuUndation in such a way that all kinds of harmful effects are eliminated Many scientists have significantly contributed to the field of machine foundation laying greater emphasis on vibration response of both machine and foundation The contributions to the practical and theoretical development of the subject, especially from authors like Geiger, Rauch, Barkan and Alexander Major, are noteworthy

The design aids /methodologies provide insight to the dynamic behaviour of foundation and its elements for satisfactory performance of the machine thus suggesting the need for the complete knowledge of load transfer mechanism from the machine to the foundation and the knowledge of excitation forces and associated frequencies for correct evaluation of machine performance

This book covers basic fundamentals necessary for understanding and evaluating dynamic response

of machine foundation system Stress is laid on detailed dynamic analysis for evaluating the response Use of commercially available Finite Element packages, for analysis and design of the foundation, is recommended The author has carried out extensive field investigations on many foundations and some of the findings are presented for comparison with analytical results

This handbook is written with the sole objective of making the practising engineers physically understand and feel the dynamics of machine foundation system Any suggestion from the readers that leads to improvement of the contents, style, etc of the handbook is welcome

K G Bhatia

a Amplitude Ratio

58 Static deflection along e

Phase angle

Mass moment of Inertia ratio

Efficiency of drop of hammer

(}o,!fo &¢o Rotations about X; Y & Z axes at DOF location '0'

(01 (02 (03 Excitationfrequencies of machine 1, 2 and 3

Area of Plate

Cr Coefficient of Uniform Displacement of Soil

C", Coefficient of Non-Uniform Displacement of Soil

Elastic Modulus o[Sheet Isolators

Fi y ' F2y Y-Component of force FJ & F2 respectively

f Frequency in Cycle per sec (Hz)

Fcy,Fez Force at point C in Y & Z direction respectively

HeiRht offall of hammer

k, kJ, k 2 ·.etc Stiffness

[k J Stiffness Matrix

ko Rotational Stiffness about X-direction

M o ", Moment at '0' about Y-axis

Mass ofTup (falling mass)

M20,M25,M30 Grade of Concrete

Mass of Crank rod

mp Mass of Piston

Number of Cylinders (in Recip}"ocatingEngine)

Number of Springs, bearing pressure

Uniform Shear Stress

Pressure in Vertical Y -direction

Uniform Shear Stress

P4,P5,P6

Ve Compression Wave Velocity

v1 Initial velucity imparted to the foundation after impact

v O ,v1 Velocity after Impact

, ,

v O ,v1 Velocity before Impact

Wmi Machine load at point 'i'

W f ] ,W(2 &Wj3 Weight of Foundation Block part I, 2 &3 resp

Wfi Weight of Foundation Block 'i'

x,y&z Displacement in X, Y & Z-directions respectively

x,y&z Overall centroid coordinates

xo,Yo & Zo Amplitudes along X, Y & Z direction at DOF location '0'

Xj'YI &zI Amplitudes along X, Y & Z direction at Center of Foundation

Top X/c'Yrc & Z Ie Amplitudes along X; Y & Z direction at Corners of Foundation

Top XI'Yr &ZI Maximum Amplitudes in X, Y & Z direction at Foundation Top

xmi'Ymi &Zmi X, Y and Z Coordinate of load point Wmi

xm &zm X & Z Coordinates of machine centroid

X1' x2' x3 Displacements of masses m1, m2, m3 in X-direction

Y1' Y2' Y3 Displacements of masses m1, m2, m3 in Y-direction

z1,z2,z3 Displacements of masses m1, m2, m3 in Z-direction

x,y&z ]"" Differential of x, y & z with respect to time

x,y&Z 2 nd Differential of x, y & z with respect to time

Yg Ground Acceleration in Y -Direction

X, Y, Z X, Y & Z Coordinate axes

zp Displacement of Piston from its extreme position

MACHINES AND FOUNDATIONS

MACHINES AND FOUNDATIONS

The performance, safety and stability of machines depend largely on their design, manufacturing and interaction with environment In principle machine foundations should be designed such that the dynamic forces of machines are transmitted to the soil through the foundation in such a way that all kinds of harmful effects are eliminated

In the past, simple methods of calculation were used most often involving the multiplication of static loads by an estimated Dynamic Factor, the result being treated as an increased static load without any knowledge of the actual safety factor Because of this uncertainty, the value of the adopted dynamic factor was usually too high, although practice showed that during operation harmful deformations did result in spite of using such excessive factors This necessitated a deeper scientific investigation of dynamic loading A more detailed study became urgent because of development of machines of higher capacities

Machines of higher ratings gave rise to considerably higher stresses thereby posing problems with respect to performance and safety This called for development partly in the field of vibration technique and partly in that of soil mechanics Hence new theoretical procedures were developed for calculating the dynamic response of foundations

It is well established that the cost of foundation is but a small fraction of that of the machine and inadequately constructed foundations may result in failures and shutdowns exceeding many times the cost of the capital investment required for properly designed and built foundations

A brief review indicates that over the years, many scientists have contributed to the field of machine foundation design Gieger in 1922 carried out investigations to determine the natural frequencies of foundations Rauch in 1924 dealt with the machine and turbine foundation and contributed greatly to the practical and theoretical development of the science A great emphasis was thus laid on to vibration problems in machine foundations Timoshenko (1928) & Den Hartog (1934) dealt with many vibration problems in engineering practices Later Wilson (1942), Arya