Elements of CIVIL ENGINEERING AND ENGINEERING MECHANICS THIRD EDITION M.N. SHESHA PRAKASH Vice Principal Professor and Head of Civil Engineering Vidya Vikas Institute of Engineering and Technology Mysore GANESH B. MOGAVEER Professor and Head, Department of Civil Engineering Mangalore Institute of Technology and Engineering Moodabidri Delhi-110092 2014 ELEMENTS OF CIVIL ENGINEERING AND ENGINEERING MECHANICS, Third Edition (with CD-ROM) M.N. Shesha Prakash and Ganesh B. Mogaveer © 2014 by PHI Learning Private Limited, Delhi. All rights reserved. No part of this book may be reproduced in any form, by mimeograph or any other means, without permission in writing from the publisher. The authors and the publisher make no warranty of any kind, expressed or implied, with regard to programs contained in this companion CD. The authors and publisher shall not be liable in any event for incidental or consequential damages in connection with, or arising out of, the furnishing, performance, or use of these programs. ISBN-978-81-203-5001-4 The export rights of this book are vested solely with the publisher. Fifth Printing (Third Edition) … … August, 2014 Published by Asoke K. Ghosh, PHI Learning Private Limited, Rimjhim House, 111, Patparganj Industrial Estate, Delhi-110092 and Printed by Mohan Makhijani at Rekha Printers Private Limited, New Delhi-110020. CONTENTS Preface vii Preface to the First Edition ix Acknowledgements xi 1. Introduction to Civil Engineering ...........................................................1–20 What is Engineering? 1 Branches of Engineering 1 Civil Engineering 2 Civil Engineering for Civilization 2 Surveying 2 Fluid Mechanics and Hydraulics 3 Transportation Engineering 3 Water Resources Engineering 4 Environmental Engineering 4 Geotechnical Engineering 4 Foundation Engineering 5 Construction Technology—Built Environment 5 Infrastructure 6 Role of Civil Engineer 7 Roads and Highways 7 Types of Roads 8 Classification of Roads by Nagpur Road Plan 9 Dams 11 Bridges 13 Types of Bridges 13 Exercise Problems 20 iii iv CONTENTS 2. Introduction to Engineering Mechanics ..............................................21–33 An Overview 21 Mechanics of Rigid Bodies 21 Mechanics of Deformable Bodies 22 Mechanics of Fluids 22 Force and Force System 22 Technical Terms Used in Engineering Mechanics 22 Newton’s Laws of Motion 23 Elements of a Force or Characteristics of a Force 23 Types of Force System 24 Principle of Transmissibility of Forces 27 Principle of Superposition of Forces 27 Principle of Physical Independence of Forces 28 Resolution of a Force 28 Composition of Forces 28 Moment of a Force 31 Couple 32 Exercise Problems 33 3. Coplanar Concurrent Force System ....................................................34–50 Definition 34 Problems on Coplanar Concurrent Force System 35 Exercise Problems 47 4. Coplanar Non-concurrent Force System.............................................51–71 Definition 51 Problems on Coplanar Non-concurrent Force System 52 Tips to Solve the Problems 52 Exercise Problems 66 5. Equilibrium of Coplanar Concurrent Force System ........................72–108 Equilibrium 72 Problems on Equilibrium of Coplanar Concurrent Force System 74 Tips to Solve the Problems 74 Exercise Problems 101 6. Equilibrium of Coplanar Non-concurrent Force System...............109–131 Support Reactions 109 Types of Supports 109 Types of Beams 110 Types of Loads 111 CONTENTS v Problems on Equilibrium of Coplanar Non-concurrent Force System 112 Tips to Solve the Problems 112 Exercise Problems 129 7. Plane Trusses .....................................................................................132–169 Engineering Structure 132 Classification of Trusses 132 Analysis of Statically Determinate Trusses 133 Exercise Problems 164 8. Friction.................................................................................................170–210 Introduction 170 Limiting Friction 171 Coefficient of Friction (m) 171 Types of Friction 171 Angle of Friction (f) 172 Angle of Repose (q) 173 Cone of Friction 174 Laws of Friction 174 Tips to Solve the Problems 175 Wedge Friction 195 Ladder Friction 202 Exercise Problems 207 9. Centroid of Plane Figures.................................................................211–247 Centre of Gravity 211 Centroid (C.G. or G) 211 Determination of Centroid by the Method of Moments 212 Axes of Reference 212 Centroidal Axis 213 Symmetrical Axis 213 Centroids of Some Important Geometrical Figures 215 Derivation of Centroid of Some Important Geometrical Figures 217 Problems on Centroid 222 Exercise Problems 244 10. Moment of Inertia ...............................................................................248–273 Introduction 248 Parallel Axis Theorem 249 Perpendicular Axis Theorem 250 vi CONTENTS Moment of Inertia of Important Figures 251 Rectangle 251 Triangle 251 Circle 253 Semicircle 253 Quarter Circle 254 Problems on Moment of Inertia 255 Steps to Solve any Given Problem 255 Exercise Problems 270 11. Kinematics ...........................................................................................274–333 Introduction to Dynamics 274 Technical Terms Related to Motion 274 Displacement and Distance Travelled 275 Average Acceleration 276 Newton’s Laws of Motion 276 Types of Motion 276 Rectilinear Motion 280 Problems on Kinematics 281 Motion under Gravity 290 Curvilinear motion 296 Introduction 296 Curvilinear Motion in Cartesian Coordinates 296 Curvilinear Motion in Polar Coordinates 310 Projectiles 317 Exercise Problems 329 Annexure 1: Useful Relationships ...........................................................335–340 Annexure 2: Elements of Civil Engineering and Mechanics (4:0:0) ...341–343 Objective Type Questions.........................................................................345–370 Examination Papers of VTU......................................................................371–473 Solutions to the Examination Papers of VTU ........................................475–543 Index.............................................................................................................545–547 PREFACE A new chapter on Kinematics has been included in this edition. Numerous problems have been included along with its solutions for the beginners to understand the concept better. The companion CD has been updated and the dynamic graphics part has been included for forces module, wherein the readers can have a feel of the force and its inclination through visualized graphics part. In addition to this, all other software modules are also updated for better usage. We whole-heartedly thank all the faculty members and students who have suggested corrections, some of which have been incorporated in the third edition. We are also indebted to the wonderful team of PHI Learning which worked for the printing and marketing of this book. M.N. Shesha Prakash Ganesh B. Mogaveer vii PREFACE TO THE FIRST EDITION The purpose of this book is to focus on introductory material pertaining to civil engineering and engineering mechanics in order to provide the first-year students of all branches with a balanced and cohesive study of these two areas as needed by them in the beginning of their engineering education. It offers the basic knowledge about various facets of civil engineering (being the oldest branch of engineering) and the related engineering structures and infrastructure such as buildings, roads, highways, dams, and bridges which exist all around us. It also briefly explains the broad scope of allied fields of civil engineering such as surveying, transportation, water resources, environmental engineering, geotechnical engineering, foundation engineering and construction technology. The engineering mechanics portion of the book has been thoroughly explained with many practical examples and an effort has been made to make the students learn the basic concepts, which will prove useful to them in their future endeavours of higher studies. The topics in engineering mechanics are organized into Forces, Centroid, Moment of Inertia and Friction. Each chapter is written in such a way that the concepts are introduced to the reader gradually and stepwise. Each chapter consists of many worked-out problems so that several different types of problems get covered. This book has also been provided with a CD wherein mini softwares are available to work out the problems on topics of Forces, Centroid, Moment of Inertia and Friction. The software is developed using MS Excel. The provision of such software overcomes restrictions on the number of problems available and this helps both the students and the faculty in several ways. The faculty can develop new types of problems with guaranteed and reliable solutions, thus helping them to set new type of questions for tests and examinations. At the same time the perusal of software helps the students to understand the fundamentals of the subject in a relatively easy manner. This book has been written in a simple and easy-to-follow language. It uses step-by-step procedures to solve problems along with adequate theory as required by the first-year engineering students. Though especially designed to conform to the syllabus of Visvesaraya Technological University (VTU), it is a basic undergraduate textbook that will be useful to several other universities. The authors invite constructive criticism and suggestions from all readers for effecting improvements in subsequent editions. M.N. Shesha Prakash Ganesh B. Mogaveer ix