Concrete Design for the Civil PE and Structural SE Exams Second Edition C. Dale Buckner, PhD, PE, SECB Professional Publications, Inc. • Belmont, California Benefit by Registering This Book with PPI • Get book updates and corrections. • Hear the latest exam news. • Obtain exclusive exam tips and strategies. • Receive special discounts. Register your book at ppi2pass.com/register. Report Errors and View Corrections for This Book PPI is grateful to every reader who notifies us of a possible error. Your feedback allows us to improve the quality and accuracy of our products. You can report errata and view corrections at ppi2pass.com/errata. CONCRETE DESIGN FOR THE CIVIL PE AND STRUCTURAL SE EXAMS Second Edition Current printing of this edition: 1 (electronic version) Printing History edition printing number number update 1 4 Minor corrections. Copyright update. 1 5 Minor corrections. 2 1 New edition. Code updates. Minor title revision. Copyright update. Copyright (cid:2)c 2014 by Professional Publications, Inc. All rights reserved. All content is copyrighted by Professional Publications, Inc. (PPI). All rights reserved. No part, either text or image, may be used for any purpose other than personal use. Reproduction, modification, storage in a retrieval system or retransmission, in any form or by any means, electronic, mechanical, or otherwise, for reasons other than personal use, without prior written permission from the publisher is strictly prohibited. For written permission, contact PPI at [email protected]. Printed in the United States of America. PPI 1250 Fifth Avenue Belmont, CA 94002 (650) 593-9119 ppi2pass.com ISBN: 978-1-59126-478-1 Library of Congress Control Number: 2014950227 Table of Contents PrefaceandAcknowledgments. . . . . . . . . . . . . . . . .vii B. Beams with Irregular Cross Sections . . . . . 12 HowtoUseThisBook. . . . . . . . . . . . . . . . . . . . . . . ix Example 3.2 CodesandReferencesUsedtoPrepareThisBook . . . . xi Analysis of an Irregularly Shaped Beam . . 13 2. Ductility Criteria . . . . . . . . . . . . . . . . . . . . . . 14 ListofTables. . . . . . . . . . . . . . . . . . . . . . . . . . . . xiii Example 3.3 ListofFigures . . . . . . . . . . . . . . . . . . . . . . . . . . . . xv Maximum and Minimum Flexural Steel Nomenclature . . . . . . . . . . . . . . . . . . . . . . . . . . . xvii in a Rectangular Beam. . . . . . . . . . . . . . . 14 3. Design of Singly Reinforced Rectangular Chapter1 Beams. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 15 Materials Example 3.4 1. Properties of Fresh and Hardened Concrete . . . 1 Flexural Steel in a Rectangular Beam . . . . 15 2. Specifying Concrete . . . . . . . . . . . . . . . . . . . . 2 A. Design Equation in Terms of the A. Unit Weight. . . . . . . . . . . . . . . . . . . . . . . 2 Steel Ratio . . . . . . . . . . . . . . . . . . . . . . . 15 B. Specified Compressive Strength. . . . . . . . . 2 Example 3.5 3. Mechanical Properties of Concrete . . . . . . . . . 2 Flexural Steel Calculated Using the A. Compressive Stress-Strain Relationship . . . 2 Steel Ratio . . . . . . . . . . . . . . . . . . . . . . . 16 B. Tensile Strength. . . . . . . . . . . . . . . . . . . . 3 4. Doubly Reinforced Beams. . . . . . . . . . . . . . . . 16 C. Volume Changes . . . . . . . . . . . . . . . . . . . 3 Example 3.6 4. Properties of Reinforcing Steel . . . . . . . . . . . . 4 Doubly Reinforced Beam Analysis . . . . . . 17 A. Reinforcing Bars . . . . . . . . . . . . . . . . . . . 4 5. Construction Considerations. . . . . . . . . . . . . . 19 B. Smooth Bars and Wire Fabric. . . . . . . . . . 4 Example 3.7 C. Mechanical Properties . . . . . . . . . . . . . . . 5 Spacing Limits for Bundled Bars. . . . . . . . 19 Chapter2 DesignSpecifications 1. Strength . . . . . . . . . . . . . . . . . . . . . . . . . . . . 7 Example 2.1 Chapter4 Factored Load Combinations for Serviceabilityof Gravity and Wind . . . . . . . . . . . . . . . . . . 8 ReinforcedConcreteBeams 2. Ductility . . . . . . . . . . . . . . . . . . . . . . . . . . . . 8 1. Linear Elastic Behavior . . . . . . . . . . . . . . . . . 21 3. Serviceability. . . . . . . . . . . . . . . . . . . . . . . . . 8 Example 4.1 4. Constructability Issues . . . . . . . . . . . . . . . . . . 9 Elastic Stresses in a Singly Reinforced Rectangular Beam . . . . . . . . . . . . . . . . . . 22 Chapter3 Example 4.2 FlexuralDesignof Elastic Deflection of a Singly Reinforced ReinforcedConcreteBeams Rectangular Beam . . . . . . . . . . . . . . . . . . 23 1. Strength . . . . . . . . . . . . . . . . . . . . . . . . . . . . 11 2. Long-Term Behavior . . . . . . . . . . . . . . . . . . . 23 A. M for a Singly Reinforced Example 4.3 n Concrete Beam . . . . . . . . . . . . . . . . . . . . 11 Elastic and Long-Term Deflection of a Example 3.1 Doubly Reinforced Rectangular Beam . . . . 24 Singly Reinforced Beam Analysis . . . . . . . 12 3. Durability Issues . . . . . . . . . . . . . . . . . . . . . . 25 --- iii --- iv ConcreteDesignfortheCivilPEandStructuralSEExams Chapter5 Chapter7 ShearDesignofReinforcedConcrete ContinuousOne-WaySystems 1. Shear Strength of Slender Reinforced 1. Advantages and Disadvantages . . . . . . . . . . . . 49 Concrete Beams. . . . . . . . . . . . . . . . . . . . . . . 27 2. ACI Gravity Load Analysis . . . . . . . . . . . . . . 50 Example 5.1 3. Solid One-Way Slabs . . . . . . . . . . . . . . . . . . . 51 Stirrup Design for a Reinforced Example 7.1 Concrete Beam . . . . . . . . . . . . . . . . . . . . 28 Design of a Solid One-Way Reinforced 2. Shear Friction . . . . . . . . . . . . . . . . . . . . . . . . 29 Concrete Slab . . . . . . . . . . . . . . . . . . . . . 52 Example 5.2 4. Ribbed One-Way Slabs. . . . . . . . . . . . . . . . . . 53 Shear Friction Reinforcement . . . . . . . . . . 29 Example 7.2 3. Brackets and Corbels . . . . . . . . . . . . . . . . . . . 30 Design of a Ribbed One-Way Reinforced Example 5.3 Concrete Slab . . . . . . . . . . . . . . . . . . . . . 54 Design of a Reinforced Concrete Corbel. . . 30 5. One-Way Beams and Girders . . . . . . . . . . . . . 56 4. Torsion . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 31 Example 7.3 Example 5.4 Design of a Girder Supporting a Torsional Design Moment . . . . . . . . . . . . . 32 Ribbed Slab. . . . . . . . . . . . . . . . . . . . . . . 56 Example 5.5 Torsional Reinforcement. . . . . . . . . . . . . . 34 Chapter8 Two-WaySlabSystems 1. Variations of Two-Way Slabs . . . . . . . . . . . . . 57 2. Minimum Thickness of Two-Way Slabs . . . . . . 58 A. Flat Plates . . . . . . . . . . . . . . . . . . . . . . . 58 Chapter6 B. Flat Slabs with Drop Panels . . . . . . . . . . . 58 ColumnsandCompressionMembers C. Two-Way Beam-Slab Systems. . . . . . . . . . 58 1. Stocky Column Behavior . . . . . . . . . . . . . . . . 37 Example 8.1 Example 6.1 Minimum Slab Thickness for a Two-Way Plastic Centroid for an Asymmetrical Beam-Slab System . . . . . . . . . . . . . . . . . . 59 Column Section . . . . . . . . . . . . . . . . . . . . 38 3. Flexural Design of Two-Way Slabs by Example 6.2 Direct Design. . . . . . . . . . . . . . . . . . . . . . . . . 60 Interaction Diagram for a Reinforced Example 8.2 Concrete Column. . . . . . . . . . . . . . . . . . . 39 Column and Middle Strips for a Flat 2. Concentrically Loaded Stocky Column . . . . . . 42 Plate System . . . . . . . . . . . . . . . . . . . . . . 60 Example 6.3 Example 8.3 Design of a Concentrically Loaded Flexural Design of a Flat Plate System . . . 62 Tied Column . . . . . . . . . . . . . . . . . . . . . . 42 4. Shear Strength of Two-Way Slabs . . . . . . . . . . 63 3. Lateral Reinforcement . . . . . . . . . . . . . . . . . . 42 Example 8.4 Example 6.4 Shear Strength of a Flat Plate System. . . . 63 Design Spiral Reinforcement . . . . . . . . . . . 43 5. Transfer of Moment to Columns in 4. Design for Combined Axial Compression Two-Way Slabs . . . . . . . . . . . . . . . . . . . . . . . 64 plus Bending . . . . . . . . . . . . . . . . . . . . . . . . . 43 Example 8.5 Example 6.5 Shear Stresses at Exterior Column for a Design Using Interaction Diagrams . . . . . . 43 Flat Plate System . . . . . . . . . . . . . . . . . . 66 5. Design of Slender Columns . . . . . . . . . . . . . . . 44 A. Magnified Moments for Columns Without Sidesway . . . . . . . . . . . . . . . . . . 44 Chapter9 Example 6.6 DevelopmentofReinforcement Slenderness Effects for a Column 1. Development of Reinforcement in Tension . . . . 67 Without Sway . . . . . . . . . . . . . . . . . . . . . 45 A. Straight Embedment . . . . . . . . . . . . . . . . 67 B. Magnified Moments for Columns Example 9.1 with Sidesway . . . . . . . . . . . . . . . . . . . . . 46 Development Lengths for Grade 60 Bars . . 68 Example 6.7 Example 9.2 Effective Length Factor for a Column Selecting Reinforcement to Ensure in a Sway Frame . . . . . . . . . . . . . . . . . . . 47 Development . . . . . . . . . . . . . . . . . . . . . . 68 6. Concrete Bearing Strength . . . . . . . . . . . . . . . 47 B. Development of Standard Hooks in Tension 69 Example 6.8 Example 9.3 Bearing of a Column on a Footing . . . . . . 48 Development of Hooked Bar in Tension . . . 69 ProfessionalPublications,Inc. TableofContents v 2. Development of Reinforcement in Chapter11 Compression . . . . . . . . . . . . . . . . . . . . . . . . . 70 SeismicDesignof Example 9.4 ReinforcedConcreteMembers Development of Rebar in Compression . . . 70 1. Flexural Members . . . . . . . . . . . . . . . . . . . . . 87 3. Development of Flexural Reinforcement . . . . . 70 Example 11.1 Example 9.5 Shear Design for a Rectangular Beam in a Bar Cutoff in a Simple Span Beam . . . . . . 70 Special Moment Frame. . . . . . . . . . . . . . . 88 Example 9.6 2. Special Moment Frame Members Subjected to Bar Cutoff in the Negative Moment Combined Bending and Axial Force . . . . . . . . 89 Region of a Continuous Beam. . . . . . . . . . 71 Example 11.2 4. Development of Web Reinforcement . . . . . . . . 72 Transverse Reinforcement for a 5. Mechanical Anchorage . . . . . . . . . . . . . . . . . . 72 Rectangular Column in a Special Moment Frame . . . . . . . . . . . . . . . . . . . . 90 Chapter10 3. Joints in Special Moment Frame Members. . . . 91 PrestressedConcrete Example 11.3 1. Prestressing Methods . . . . . . . . . . . . . . . . . . . 73 Joint Reinforcement for a 2. Materials. . . . . . . . . . . . . . . . . . . . . . . . . . . . 74 Rectangular Column in a Special 3. Changes in Prestress Force with Time. . . . . . . 74 Moment Frame . . . . . . . . . . . . . . . . . . . . 92 A. Pretensioned Members . . . . . . . . . . . . . . . 74 4. Special Reinforced Concrete Walls . . . . . . . . . 93 B. Post-tensioned Members. . . . . . . . . . . . . . 75 A. Shear Strength. . . . . . . . . . . . . . . . . . . . . 93 4. Serviceability of Prestressed Members . . . . . . . 75 B. Strength in Flexure and Axial Load . . . . . 93 Example 10.1 Example 11.4 Stress Calculations for a Pretensioned Longitudinal and Shear Reinforcement in Beam . . . . . . . . . . . . . . . . . . . . . . . . . . . 76 a Special Shear Wall . . . . . . . . . . . . . . . . 94 Example 10.2 5. Reinforced Concrete Structural Diaphragms . . 95 Deflections in a Pretensioned Beam. . . . . . 77 Example 11.5 Example 10.3 Shear and Chord Forces in a Equivalent Loads for a Post-tensioned Rigid Diaphragm . . . . . . . . . . . . . . . . . . . 96 Beam . . . . . . . . . . . . . . . . . . . . . . . . . . . 78 5. Flexural Strength of Prestressed Members . . . . 78 Chapter12 A. General Analysis by Strain PracticeProblems Compatibility . . . . . . . . . . . . . . . . . . . . . 79 Civil PE and SE Breadth Exam Problems Example 10.4 Practice Problems 1–25 . . . . . . . . . . . . . . . . . 99 Flexural Strength by Strain SE Breadth Exam Problems Compatibility Analysis. . . . . . . . . . . . . . . 79 Practice Problems 26–35 . . . . . . . . . . . . . . . 125 B. Ductility Considerations. . . . . . . . . . . . . . 80 SE Depth Exam Problems Example 10.5 Practice Problems 36–37 . . . . . . . . . . . . . . . 135 Ductility Requirements for a Prestressed Beam. . . . . . . . . . . . . . . . . . . 81 Index. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 149 C. Approximate Analysis Using ACI Equations. . . . . . . . . . . . . . . . . . . . . 81 Example 10.6 Nominal Moment Strength Using ACI Approximate Equations . . . . . . . . . . . . . . 82 6. Shear Strength of Prestressed Members. . . . . . 82 Example 10.7 Shear Reinforcement in a Prestressed Beam . . . . . . . . . . . . . . . . . . . . . . . . . . . 82 7. Continuous Prestressed Concrete Beams . . . . . 84 Example 10.8 Secondary Moments in a Prestressed Beam . . . . . . . . . . . . . . . . . . . . . . . . . . . 84 ProfessionalPublications,Inc. Preface and Acknowledgments I have written this book primarily for engineers who Whilestudyingthisbook, you’llneedtohaveacopy are studying to take the NCEES 16-hr structural en- of the building code ACI 318 at hand. Either the 2008 gineering (SE) exam or the structural depth section of or the 2011 edition will do for this purpose, because the NCEES civil Principles and Practice of Engineer- thereareonlyminordifferencesbetweentheminregard ing (PE) exam. The civil PE and SE exams—even the to the problems covered in this book. (For the exam breadth section of the civil PE exam—often contain itself, however, you will want to have the same edition structural questions that go beyond the basics. This the current exam is based on. This is explained more book provides a more thorough review for those who fully in How to Use This Book.) wanttobepreparedforallquestionsinconcretedesign. I appreciate the help provided by John Mercer, PE, It is also suitable as a reference for students taking in- who reviewed an early draft of the first edition. Thank troductorycoursesinreinforcedorprestressedconcrete. you to PPI’s product development and implementation Forthissecondedition,nomenclature,equations,ex- staff, including Sarah Hubbard, director of product de- amples, and practice problems have been updated so velopmentandimplementation;CathySchrott,produc- that they are consistent with NCEES-adopted codes tionservicesmanager;JennyLindeburgKing,associate and specifications. editor-in-chief;MagnoliaMolcan,editorialprojectman- This is not a comprehensive textbook on the theory ager; Ellen Nordman, lead editor on this book; David of reinforced concrete structures. I have included the Chu, Nicole Evans, Julia Lopez, Scott Marley, and basictheoryyouwillneedtosolvethetypesofconcrete Heather Turbeville, copy editors; Ralph Arcena, EIT, design problems likely to appear on the exams, but I calculation checker; Tom Bergstrom, technical illustra- have not gone into detailed derivations and historical tor; and Kate Hayes, production associate. summaries of code criteria. Among the topics covered Finally,ifyoufindanerrorinthisbook,pleaseletme inthisbookaretheeffectsofflexure,shear,torsion,and knowbyusingtheerrorreportingformonthePPIweb- axial loads on members; serviceability; development of site, found atppi2pass.com/errata. Valid submitted reinforcement; behavior of one-way and two-way floor errors will be posted to the errata page and incorpo- systems; prestressedconcretemembers; andseismicde- rated into future printings of this book. sign criteria. IhaveincludedmanyexamplestoillustratehowACI C. Dale Buckner, PhD, PE, SECB code criteria should be applied, and in the last chapter you will find 37 practice problems with complete solu- tions. Only U.S. customary units are used in these ex- amplesandpracticeproblems,consistentwiththeexam format. --- vii --- How to Use This Book WhatYou’llNeed StudyingwithThisBook This book is designed to complement and be used with Each chapter in this book treats a different topic. If PPI’s Civil Engineering Reference Manual (CERM), you only want to brush up on a few specific subjects, Structural Depth Reference Manual (CEST), or Struc- you may want to study only those particular chapters. tural Engineering Reference Manual (STRM). CERM, However, later chapters frequently build on concepts CEST,andSTRMarethebasictextsforanyonestudy- and information that have been set out in earlier chap- ing for the civil PE or structural engineering (SE) ters,andthebookismosteasilystudiedbyreadingthe exams, and each book contains an introduction to the chapters in order. basic concepts and most common applications pertain- The civil PE and SE exams are open book, so it is a ing to concrete design. verygoodideaasyoustudytomarkpagesinbothACI It is essential that this book be used with the Amer- 318 and this book that contain important information, ican Concrete Institute’s Building Code Requirements such as tables, graphs, and commonly used equations, for Structural Concrete (ACI 318) and Commentary forquickreferenceduringtheexam. (Somestatesdon’t (ACI 318R). The following chapters are meant to ex- allow removable tabs in books brought into the exam. plainandclarifythoseaspectsofthebuildingcodethat Check with your state board, or use permanent tabs.) are most likely to come up during the civil PE and SE Become as familiar as possible with this book and with exams, but it will be frequently assumed along the way ACI318. Rememberthatpreparationandorganization that you can refer directly to the code itself when nec- are as important to passing the PE and SE exams as essary. knowledge is. Throughoutthebook, citationstocodecriteriarefer Throughout the book, example problems illustrate tothe2011editionoftheACIcode. Forexample,theci- how to use the standard design principles, methods, tation“ACISec.7.12”referstoSec.7.12ofACI318-11. and formulas to tackle common situations you may en- For the problems covered in this book, however, the counter on the exam. Take your time with these and differencesbetweenACI318-08andACI318-11aremi- make sure you understand each example before moving nor and amount to no more than the notation used for ahead. Keepinmind, though, thatinactualdesignsit- a few variables. That means you can study this book uations there are often several correct solutions to the with either ACI 318-08 or ACI 318-11 at hand. same problem. When it comes to the exam itself, of course, it’s im- portant to bring the editions of the design standards PracticeProblemsforEachExam that the current exam is based on. Check the NCEES website at ncees.org for the current design standards In the last chapter of the book you’ll find 37 practice for your exam. You can also check PPI’s website at problems. Whether you’re studying for the structural ppi2pass.com/civil or ppi2pass.com/structural depth section of the civil PE exam, or the SE exam, forcurrentinformationandanswerstofrequentlyasked you’ll find practice problems that are similar in scope, questions (FAQs) about the civil PE or SE exams. subject matter, and difficulty to problems you’ll en- Appendix C in both ACI 318-08 and ACI 318-11 counter on the actual exam. permits an alternative design approach using load and The NCEES PE exam in civil engineering consists resistance factors from earlier code editions. Neverthe- of two 4-hour sections, separated by a one-hour lunch less, the examples and practice problems in this book period. Both sections contain 40 multiple-choice prob- employ only the unified approach consistent with the lems, andyoumustanswer allproblemsineachsection main body of ACI 318. to receive full credit. There are no optional questions. --- ix ---