Dynamics of Structure and Foundation - A Unified Approach

Abstract

Preface 1 Dynamic soil structure interaction *1.1 Introduction *1.1.1 The marriage of soil and structure *1.1.2 What does the interaction mean? *1.1.3 It is an expensive analysis do we need to do it? *1.1.4 Different soil models and their coupling to superstructure *1.2 Mathematical modeling of soil & structure *1.2.1 Lagrangian formulation for 2D frames or stick-models *1.2.2 What happens if the raft is flexible? *1.3 A generalised model for dynamic soil structure interaction *1.3.1 Dynamic response of a structure with multi degree of freedom considering the underlying * soil stiffness *1.3.2 Extension of the above theory to system with multi degree of freedom *1.3.3 Estimation of damping ratio for the soil structure system *1.3.4 Formulation of damping ratio for single degree of freedom *1.3.5 Extension of the above theory to systems with multi-degree freedom *1.3.6 Some fallacies in coupling of soil and structure *1.3.7 What makes the structural response attenuate or amplify? *1.4 The art of modelling *1.4.1 Some modelling techniques *1.4.2 To sum it up *1.5 Geotechnical considerations for dynamic soil structure interaction *1.5.1 What parameters do I look for in the soil report? *1.6 Field tests *1.6.1 Block vibration test *1.6.2 Seismic cross hole test *1.6.3 How do I co-relate dynamic shear modulus when I do not have data from the dynamic * soil tests? *1.7 Theoretical co-relation from other soil parameters *1.7.1 Co-relation for sandy and gravelly soil *1.7.2 Co-relation for saturated clay *1.8 Estimation of material damping of soil *1.8.1 Whitman's formula *1.8.2 Hardin' formula *1.8.3 Ishibashi and Zhang's formula *1.9 All things said and done how do we estimate the strain in soil, specially if the strain is large? *1.9.1 Estimation of strain in soil for machine foundation *1.9.2 Estimation of soil strain for earthquake analysis *1.9.3 What do we do if the soil is layered with varying soil property? *1.9.4 Checklist of parameters to be looked in the soil reports *1.10 Epilogue 2. Analysis and design of machine foundations *2.1 Introduction *2.1.1 Case history #1 *2.1.2 Case history #2 *2.2 Different types of foundations *2.2.1 Block foundations resting on soil/piles *2.2.2 How does a block foundation supporting rotating machines differ from a normal * foundation? *2.2.3 Foundation for centrifugal or rotary type of machine: Different theoretical methods * for analysis of block foundation *2.2.4 Analytical methods *2.2.5 Approximate analysis to de-couple equations with non-proportional damping *2.2.6 Alternative formulation of coupled equation of motion for sliding and rocking mode *2.3 Trick to by pass damping - Magnification factor, the key to the problem *2.4 Effect of embedment on foundation *2.4.1 Novak and Beredugo's model *2.4.2 Wolf's model *2.5 Foundation supported on piles *2.5.1 Pile and soil modelled as finite element *2.5.2 Piles modelled as beams supported on elastic springs *2.5.3 Novak's (1974) model for equivalent spring stiffness for piles 1 *2.5.4 Equivalent pile springs in vertical direction *2.5.5 The group effect on the vertical spring and damping value of the piles *2.5.6 Effect of pile cap on the spring and damping stiffness *2.5.7 Equivalent pile springs and damping in the horizontal direction *2.5.8 Equivalent pile springs and damping in rocking motion *2.5.9 Group effect for rotational motion *2.5.10 Model for dynamic response of pile *2.5.11 Dynamic analysis of laterally loaded piles *2.5.12 Partially embedded piles under rocking mode *2.5.13 Group effect of pile *2.5.14 Comparison of results *2.5.15 Practical aspects of design of machine foundations *2.6 Special provisions of IS-code *2.6.1 Recommendations on vibration isolation *2.6.2 Frequency separation *2.6.3 Permissible amplitudes *2.6.4 Permissible stresses *2.6.5 Concrete and its placing *2.6.6 Reinforcements *2.6.7 Cover to concrete *2.7 Analysis and design of machine foundation under impact loading *2.7.1 Introduction *2.7.2 Mathematical model of a hammer foundation *2.8 Design of hammer foundation *2.8.1 Design criteria for hammer foundation *2.8.2 Discussion on the IS-code method of analysis *2.8.3 Check list for analysis of hammer foundation *2.8.4 Other techniques of analysis of Hammer foundation *2.9 Design of eccentrically loaded hammer foundation *2.9.1 Mathematical formulation of anvil placed eccentrically on a foundation *2.9.2 Damped equation of motion with eccentric anvil *2.10 Details of design *2.10.1 Reinforcement detailing *2.10.2 Construction procedure *2.11 Vibration measuring instruments *2.11.1 Some background on vibration measuring instruments and their application *2.11.2 Response due to motion of the support *2.11.3 Vibration pick-ups *2.12 Evaluation of friction damping from energy consideration *2.13 Vibration isolation *2.13.1 Active isolation *2.13.2 Passive isolation *2.13.3 Isolation by trench *2.14 Machine foundation supported on frames *2.14.1 Introduction *2.14.2 Different types of turbines and the generation process *2.14.3 Layout planning *2.14.4 Vibration analysis of turbine foundations *2.15 Dynamic soil-structure interaction model for vibration analysis of turbine foundation *2.16 Computer analysis of turbine foundation based on multi degree of freedom *2.17 Analysis of turbine foundation *2.17.1 The analysis *2.17.2 Calculation of the eigen values *2.17.3 So the ground rule is *2.17.4 Calculation of amplitude *2.17.5 Calculation of moments, shears and torsion *2.17.6 Practical aspects of design of Turbine foundation *2.18 Design of turbine foundation *2.18.1 Check list for turbine foundation design *2.18.2 Spring mounted turbine foundation 3. Analytical and design concepts for earthquake engineering *3.1 Introduction *3.1.1 Why do earthquakes happen in nature? *3.1.2 Essential difference between systems subjected to earthquake and vibration from machine *3.1.3 Some history of major earthquakes around the world *3.1.4 Intensity *3.1.5 Effect of earthquake on soil-foundation system *3.1.6 Liquefaction analysis *3.2 Earthquake analysis *3.2.1 Seismic coefficient method *3.2.2 Response spectrum method *3.2.3 Dynamic analysis under earthquake loading *3.2.4 How do we evaluate the earthquake force? *3.2.5 Earthquake analysis of systems with multidegree of freedom *3.2.6 Modal combination of forces *3.3 Time history analysis under earthquake force *3.3.1 Earthquake analysis of tall chimneys and stack like structure *3.4 Analysis of concrete dams *3.4.1 Earthquake analysis of concrete dam *3.4.2 A method for dynamic analysis of concrete dam *3.5 Analysis of earth dams and embankments *3.5.1 Dynamic earthquake analysis of earth dams *3.5.2 Mononobe's method for analysis of earth dam *3.5.3 Gazetas' method for earth dam analysis *3.5.4 Makadisi and Seed's method for analysis of earth dam *3.5.5 Calculation of seismic force in dam and its stability *3.6 Analysis of earth retaining structures *3.6.1 Earthquake analysis of earth retaining structures *3.6.2 Mononobe's method of analysis of retaining wall *3.6.3 Seed and Whitman's method *3.6.4 Arango's method *3.6.5 Steedman and Zeng's method *3.6.6 Dynamic analysis of RCC retaining wall *3.6.7 Dynamic analysis of cantilever and counterfort retaining wall *3.6.8 Some discussions on the above method *3.6.9 Extension to the generic case of soil at a slope i behind the wall *3.6.10 Dynamic analysis of counterfort retaining wall *3.6.11 Soil sloped at an angle i with horizontal *3.7 Unyielding earth retaining structures *3.7.1 Earthquake Analysis of rigid walls when the soil does not yield *3.7.2 Ostadan's method *3.8 Earthquake analysis of water tanks *3.8.1 Analysis of water tanks under earthquake force *3.8.2 Impulsive time period for non rigid walls *3.8.3 Sloshing time period of the vibrating fluid *3.8.4 Calculation of horizontal seismic force for tank resting on ground *3.8.5 Calculation of base shear for tanks resting on ground *3.8.6 Calculation of bending moment on the tank wall resting on the ground *3.8.7 Calculation of hydrodynamic pressure *3.9 Mathematical model for overhead tanks under earthquake *3.9.1 Earthquake Analysis for overhead tanks *3.9.2 Hydrodynamic pressure on tank wall and base *3.9.3 Hydrodynamic pressure for circular tank *3.9.4 Hydrodynamic pressure for rectangular tank *3.9.5 Effect of vertical ground acceleration *3.9.6 Pressure due to inertia of the wall *3.9.7 Maximum design dynamic pressure *3.10 Practical aspects of earthquake engineering *3.10.1 Epilogue References Subject index