Km 3000 portable key mill

Construction Methods & Materials

Assignment 2

Problems 1-9 at the end of Chapter 5

Problems 1- 4 at the end of Chapter 6

Note: Text book 7th edition is for reference only . 8th edition required

Chpt 5 question 1-9

1. Why might the laboratory and field optimum moisture contents vary for a particular soil?

2. List the types of compactors which are available for compaction in confined space?

3. a. What is a compaction wheel?

b. what is the typical lift thickness for an excavator – mounted compaction wheel?

c. State the minimum pipe cover which should be used when compacting with an excavator –mounted compaction wheel.

4. What kind of compactor would you expect to be most suitable for compacting a clean sand?

5. Estimate the production in compacted cubic yards (meters) per hour of a self-propelled tamping foot roller under the following conditions: average speed = 5 mph (8.0km/h), compacted lift thickness = inches. (15.2 cm), effective roller width = 10 ft (3.05), job efficiency = 0.75, and number of passes = 8.

6. twenty miles (32km) of gravel road require reshaping and leveling. You estimate that the moto grader will require two passes at 3 mph (8.9 km/h) to accomplish the work. How many grader hours will be required for this work if the job efficiency factor is 0.75?

7. See attachment q7
8. See attachment q8
9. List the four principal methods for achieving ground modification or soil stabilization. Provide one example of each.

Chpt 6 question 1-4

1. see attachment chpt 6 q1

2. List five safety precautions that should be observed in storing and handling blast agents?

3. You measure a seimic velocity of 900 ft/s (2743 m/s) in limestone. Would you expect this rock to be rippable by a D9H tractor equipped with a ripper (Figure 6-17) if so, would you recommend using a single or tandem ripper in this situation? Why?

4.
Text Book 7th ed

-Construction-Methods-and-Management.pdf

SEVENTH EDITION

Construction Methods and Management

S. W. NUNNALLY Consulting Engineer Professor Emeritus North Carolina State University

Upper Saddle River, New Jersey Columbus, Ohio

Library of Congress Cataloging-in-Publication Data Nunnally, S. W.

Construction methods and management / S.W. Nunnally—7th ed. p. cm.

Includes bibliographical references and index. ISBN 0-13-171685-9 1. Building 2. Construction industry—Management. I. Title.

TH145.N86 2007 624—dc22

2006044768

Editor-in-Chief: Vernon Anthony Senior Acquisitions Editor: Tim Peyton Editorial Assistant: Nancy Kesterson Production Editor: Holly Shufeldt Design Coordinator: Diane Ernsberger Cover Designer: Jeff Vanik Cover photo: Superstock Production Manager: Deidra Schwartz Executive Marketing Manager: Derril Trakalo Senior Marketing Coordinator: Liz Farrell Marketing Assistant: Les Roberts

This book was set in Times Roman by GGS Book Services. It was printed and bound by R.R. Donnelley & Sons Company. The cover was printed by The Lehigh Press, Inc.

Copyright © 2007, 2004, 2001, 1998, 1993, 1987, 1980 by Pearson Education, Inc., Upper Saddle River, New Jersey 07458. Pearson Prentice Hall. All rights reserved. Printed in the United States of America. This publication is protected by Copyright and permission should be obtained from the publisher prior to any prohibited reproduction, storage in a retrieval system, or transmission in any form or by any means, electronic, mechanical, photocopying, recording, or likewise. For information regarding permission(s), write to: Rights and Permissions Department.

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10 9 8 7 6 5 4 3 2 1 ISBN 0-13-171685-9

To Joan, Steve, Jan, and John

Preface

iv

This book is based on the author’s years of experience in construction, engineering, and education. The objective of this seventh edition continues to be to guide construction engineers and construction managers in planning, estimating, and directing construction operations in a manner that will attain the best possible results. It is believed that the ma- terial presented is comprehensive enough to serve as the basic text for a variety of con- struction courses as well as for self-study. For an introductory course, upper-division college and university-level students should be able to cover the material in one semester. For more in-depth coverage, the material may be split between two or more courses. Top- ics may, of course, be omitted or augmented as appropriate to the nature of the course and the desires of the instructor. In solving the computer problems contained in the end-of- chapter exercises, it is suggested that students be encouraged to use electronic spread- sheets and their associated functions in addition to conventional computer programming languages. Instructors are reminded that an Instructor’s Manual is available from the pub- lisher. It is strongly recommended that study of the text in an academic environment be supplemented by visits to construction projects and/or audiovisual material.

Responding to industry developments and user comments, this edition incorporates new and revised material to reflect current developments in the construction industry. New and expanded topics include building codes, concrete and masonry construction, con- struction economics, construction productivity, construction safety, design of concrete formwork, fuel-resistant asphalt, soil and asphalt compaction, and wood preservation, in addition to updated text, illustrations, references, and end-of-chapter problems.

It would not be possible to produce a book of this type without the assistance of many individuals and organizations. The assistance of construction industry associations and construction equipment manufacturers in providing information and photographs and in per- mitting reproduction of certain elements of their material is gratefully acknowledged. Where possible, appropriate credit has been provided. I would also like to express my appreciation to my colleagues and to my former students for their helpful comments and suggestions. In addition, particular thanks are due to Charles Patrick, Ph.D., Virginia Polytechnic Institute and State University, for his assistance with the seventh edition text review.

Comments from readers regarding errors and suggestions for improvement are solicited. Please send to nunnallysj@juno.com.

S. W. Nunnally

Contents

1 Introduction 1 1–1 The Construction Industry 1 1–2 The Construction Process 3 1–3 Codes and Regulations 8 1–4 State of the Industry 10 1–5 Construction Management 11 1–6 Construction Trends and Prospects 15

Problems 16 References 16

PART ONE Earthmoving and Heavy Construction 17

2 Earthmoving Materials and Operations 19 2–1 Introduction to Earthmoving 19 2–2 Earthmoving Materials 21 2–3 Soil Identification and Classification 22 2–4 Soil Volume-Change Characteristics 26 2–5 Spoil Banks 30 2–6 Estimating Earthwork Volume 32 2–7 Construction Use of the Mass Diagram 36

Problems 39 References 40

3 Excavating and Lifting 41 3–1 Introduction 41 3–2 Hydraulic Excavators 46 3–3 Shovels 50 3–4 Draglines 54

v

3–5 Clamshells 60 3–6 Trenching and Trenchless Technology 62 3–7 Cranes 66

Problems 78 References 79

4 Loading and Hauling 81 4–1 Estimating Equipment Travel Time 81 4–2 Dozers 91 4–3 Loaders 98 4–4 Scrapers 106 4–5 Trucks and Wagons 118

Problems 124 References 125

5 Compacting and Finishing 127 5–1 Principles of Compaction 127 5–2 Compaction Equipment and Procedures 132 5–3 Ground Modification 143 5–4 Grading and Finishing 146

Problems 152 References 153

6 Rock Excavation 155 6–1 Introduction 155 6–2 Drilling 160 6–3 Blasting 168 6–4 Rock Ripping 176 6–5 Estimating Production and Cost 179

Problems 182 References 183

7 Production of Aggregate, Concrete, and Asphalt Mixes 185 7–1 Production of Aggregate 185 7–2 Production of Concrete 196 7–3 Production of Asphalt Mixes 206

Problems 211 References 213

8 Paving and Surface Treatments 215 8–1 Concrete Paving 215 8–2 Asphalt Paving and Surface Treatments 219

vi CONTENTS

8–3 Pavement Repair and Rehabilitation 227 Problems 231 References 231

9 Compressed Air and Water Systems 233 9–1 Introduction 233 9–2 Compressed Air Systems 233 9–3 Water Supply Systems 246

Problems 259 References 260

PART TWO Building Construction 261

10 Foundations 263 10–1 Foundation Systems 263 10–2 Spread Footings 263 10–3 Piles 265 10–4 Piers and Caissons 275 10–5 Stability of Excavations 276 10–6 Protecting Excavations and Workers 281 10–7 Dewatering Excavations 286 10–8 Pressure Grouting 289

Problems 292 References 293

11 Wood Construction 295 11–1 Introduction 295 11–2 Wood Materials and Properties 295 11–3 Frame Construction 300 11–4 Timber Construction 321 11–5 Fastenings, Connections, and Notching 327

Problems 333 References 333

12 Concrete Construction 335 12–1 Construction Applications of Concrete 335 12–2 Concrete Construction Practices 346 12–3 Concrete Formwork 352 12–4 Reinforcing Steel 361 12–5 Quality Control 367

Problems 368 References 369

CONTENTS vii

viii CONTENTS

13 Concrete Form Design 371 13–1 Design Principles 371 13–2 Design Loads 371 13–3 Method of Analysis 374 13–4 Slab Form Design 376 13–5 Wall and Column Form Design 390 13–6 Design of Lateral Bracing 396

Problems 400 References 401

14 Masonry Construction 403 14–1 Brick Masonry 403 14–2 Concrete Masonry 414 14–3 Other Masonry Materials 420 14–4 Estimating Quantity of Masonry 422 14–5 Construction Practice 424

Problems 430 References 430

15 Steel Construction 433 15–1 Introduction 433 15–2 Structural Steel 434 15–3 Steel Erection 438 15–4 Field Connections 443 15–5 Safety 448

Problems 449 References 449

PART THREE Construction Management 451

16 Planning and Scheduling 453 16–1 Introduction 453 16–2 Bar Graph Method 454 16–3 CPM—The Critical Path Method 459 16–4 Scheduling and Resource Assignment Using CPM 471 16–5 Practical Considerations in Network Use 475 16–6 Linear Scheduling Methods 476

Problems 478 References 480

17 Construction Economics 481 17–1 Introduction 481 17–2 Time Value of Money 481

17–3 Equipment Cost 482 17–4 Equipment Rental 494 17–5 The Rent-Lease-Buy Decision 495 17–6 Financial Management of Construction 498

Problems 502 References 504

18 Contract Construction 505 18–1 Introduction 505 18–2 Bidding and Contract Award 505 18–3 Construction Contracts 508 18–4 Plans and Specifications 511 18–5 Contract Administration 512

Problems 515 References 516

19 Construction Safety and Health and Equipment Maintenance 517 19–1 Importance of Safety 517 19–2 OSHA 518 19–3 Safety Programs 518 19–4 Safety Procedures 520 19–5 Environmental Health in Construction 523 19–6 Equipment Maintenance 525

Problems 529 References 530

20 Improving Productivity and Performance 531 20–1 The Big Picture 531 20–2 Work Improvement 532 20–3 Quantitative Management Methods 539 20–4 Computers and Other Tools 544 20–5 Robots in Construction 548 20–6 The Future 550

Problems 551 References 552

Appendix A: Metric Conversion Factors 553

Appendix B: Construction Industry Organizations 554

Appendix C: Construction Internet Sources 558

Index 559

CONTENTS ix

1

1–1 THE CONSTRUCTION INDUSTRY

Introduction

1

The construction industry (including design, new and renovation construction, and the man- ufacture and supply of building materials and equipment) is one of the largest industries in the United States, historically accounting for about 10% of the nation’s gross national prod- uct and employing some 10 million workers (references 2 and 3). Annual U.S. new con- struction volume has exceeded $800 billion in recent years. Because construction is an exciting, dynamic process which often provides high income for workers and contractors, it is an appealing career opportunity. However, the seasonal and sporadic nature of construc- tion work often serves to significantly reduce the annual income of many workers. In addi- tion, construction contracting is a very competitive business with a high rate of bankruptcy.

It is widely recognized that construction as a discipline is a combination of art and science. While understanding the technical aspects of construction is extremely important, it is also essential that construction professionals have knowledge of the business and man- agement aspects of the profession. Close observation and participation in actual construc- tion projects is very valuable in obtaining an understanding of the construction process as well. Thus, the author encourages those who are studying construction in an academic en- vironment to take every opportunity to observe and participate in actual construction ac- tivities. An understanding of the topics presented in the following chapters will provide a foundation in the methods and management of construction.

While construction has traditionally been a very conservative industry, the increasing rate of technological development and growing international competition in the industry are serving to accelerate the development of new construction methods, equipment, materials, and management techniques. As a result, coming years will see an increasing need for in- novative and professionally competent construction professionals.

Construction Contractors

Companies and individuals engaged in the business of construction are commonly referred to as construction contractors (or simply contractors) because they operate under a contract arrangement with the owner. Construction contractors may be classified as general contractors

2 CHAPTER 1

Figure 1–1 Construction of St. Louis Gateway Arch. (Courtesy of American Institute of Steel Construction)

or specialty contractors. General contractors engage in a wide range of construction activities and execute most major construction projects. When they enter into a contract with an owner to provide complete construction services, they are called prime contractors. Specialty contrac- tors limit their activities to one or more construction specialties, such as electrical work, plumb- ing, heating and ventilating, or earthmoving. Specialty contractors are often employed by a prime contractor to accomplish some specific phase of a construction project. Since the spe- cialty contractors are operating under subcontracts between themselves and the prime contrac- tor, the specialty contractors are referred to as subcontractors. Thus, the terms “subcontractor” and “prime contractor” are defined by the contract arrangement involved, not by the work clas- sification of the contractors themselves. Thus, a specialty contractor employed by an owner to carry out a particular project might employ a general contractor to execute some phase of the project. In this situation, the specialty contractor becomes the prime contractor for the project and the general contractor becomes a subcontractor.

While the number of construction contractors in the United States has been estimated to exceed 800,000, some 60% of these firms employ three or fewer workers. Contractors em- ploying 100 or more workers make up less than 1% of the nation’s construction firms but ac- count for about 30% of the value of work performed. The trend in recent years has been for the large construction firms to capture an increasing share of the total U.S. construction market.

INTRODUCTION 3

1–2 THE CONSTRUCTION PROCESS

Project Development and Contract Procedures

The major steps in the construction contracting process include bid solicitation, bid prepa- ration, bid submission, contract award, and contract administration. These activities are de- scribed in Chapter 18. However, before the bidding process can take place, the owner must determine the requirements for the project and have the necessary plans, specifications, and other documents prepared. These activities make up the project development phase of construction. For major projects, steps in the project development process include:

• Recognizing the need for the project.

• Determining the technical and financial feasibility of the project.

• Preparing detailed plans, specifications, and cost estimates for the project.

• Obtaining approval from regulatory agencies. This involves ascertaining compliance with zoning regulations, building codes, and environmental and other regulations.

For small projects, many of these steps may be accomplished on a very informal basis. However, for large or complex projects this process may require years to complete.

How Construction Is Accomplished

The principal methods by which facilities are constructed are illustrated in Figures 1–5 to 1–9. These include:

• Construction employing an owner construction force.

• Owner management of construction.

• Construction by a general contractor.

Construction Industry Divisions

The major divisions of the construction industry consist of building construction (also called “vertical construction”) and heavy construction (also called “horizontal construction”). The distribution of total U.S. construction volume for a representative year is illustrated in Figure 1–2. Building construction (Figure 1–3), as the name implies, involves the construc- tion of buildings. This category may be subdivided into public and private, residential and nonresidential building construction. While building construction accounts for a majority of the total U.S. new construction market (see Figure 1–2), many of the largest and most spec- tacular projects fall in the heavy construction area. Heavy construction (Figure 1–4) includes highways, airports, railroads, bridges, canals, harbors, dams, and other major public works. Other specialty divisions of the construction industry sometimes used include industrial construction, process plant construction, marine construction, and utility construction.

4

Private building = 71%

Public nonbuilding

= 12%

Private

nonbuilding

= 7%

Public building

= 10%

Figure 1–2 Distribution of U.S. new construction volume. (Source: Bureau of the Census)

Figure 1–3 Modern building construction project.

INTRODUCTION 5

Figure 1–4 Heavy construction project—Kennedy Space Center launch complex. (U.S. Air Force photograph)

• Construction using a design/build (turnkey) contract.

• Construction utilizing a construction management contract.

Many large industrial organizations, as well as a number of governmental agencies, pos- sess their own construction forces.Although these forces are utilized primarily for performing repair, maintenance, and alteration work, they are often capable of undertaking new construc- tion projects (Figure 1–5). More frequently, owners utilize their construction staffs to manage their new construction (Figure 1–6). The work may be carried out by workers hired directly by the owner (force account), by specialty contractors, or by a combination of these two methods.

Construction by a general contractor operating under a prime contract is probably the most common method of having a facility constructed (Figure 1–7). However, two newer methods of obtaining construction services are finding increasing use: design/build (or

6 CHAPTER 1

Figure 1–5 Construction employing owner construction forces.

Figure 1–6 Owner-managed construction. [Either (a) or (b) or both may be employed.]

turnkey) construction and construction utilizing a construction management contract. Un- der the design/build or turnkey construction concept (Figure 1–8), an owner contracts with a firm to both design and build a facility meeting certain specified (usually, performance- oriented) requirements. Such contracts are frequently utilized by construction firms that spe- cialize in a particular type of construction and possess standard designs which they modify to suit the owner’s needs. Since the same organization is both designing and building the fa- cility, coordination problems are minimized and construction can begin before completion of final design. (Under conventional construction procedures it is also possible to begin con- struction before design has been completed. In this case, the construction contract is nor- mally on a cost-reimbursement basis. This type of construction is referred to as fast-track

INTRODUCTION 7

Figure 1–7 Construction by a general contractor.

Figure 1–8 Construction employing a design/build firm.

construction.) The major disadvantages of the design/build concept are the difficulty of ob- taining competition between suppliers and the complexity of evaluating their proposals.

Construction of a facility utilizing a construction management contract (Figure 1–9) is also somewhat different from the conventional construction procedure. Under the usual arrangement, also known as Agency Construction Management, a professional construction manager (CM) acts as the owner’s agent to direct both the design and construction of a fa- cility. Three separate contracts are awarded by the owner for design, construction, and con- struction management of the project. This arrangement offers potential savings in both time and cost compared to conventional procedures, as a result of the close coordination between design and construction. However, opponents of the method point out that the construction manager (CM) typically assumes little or no financial responsibility for the project and that the cost of his/her services may outweigh any savings resulting from improved coordination

8 CHAPTER 1

Figure 1–9 Construction utilizing a construction management contract.

between design and construction. There is another, less common form of construction man- agement contract known as Guaranteed Maximum Price Construction Management. Under this arrangement, the construction manager guarantees that the project cost will not exceed a specified amount. Under this procedure, which entails a certain amount of contractor risk, the construction contract is also normally held by the construction manager.

1–3 CODES AND REGULATIONS

Projects constructed in most areas of the United States must comply with a number of gov- ernmental regulations. These include building codes, zoning regulations, environmental regulations, and contractor licensing laws, among others.

Building Codes

Building codes, which are concerned primarily with public safety, provide minimum design and construction standards for structural and fire safety. As the name implies, such codes apply only to the construction of buildings. In the United States, the Board of Fire Under- writers in 1905 published a Recommended National Building Code, which provided mini- mum standards for fire protection and structural safety. This code, later known as the Basic/National Building Code, published by the Building Officials and Code Administra- tors International, was the only nationally recognized building code for a number of years. Other major building codes later published include the Uniform Building Code published by the International Conference of Building Officials and the Standard Building Code published by the Southern Building Code Congress International. In 1994 these three model code groups jointly formed the International Code Council (ICC) to publish a single

INTRODUCTION 9

set of model construction codes. Some of the International Codes since published include the International Building Code and the International Residential Code (which governs the construction of one- and two-family dwellings). A majority of the U.S. states and the Dis- trict of Columbia have adopted these two building codes. The International Code Council has also published a number of other International Codes, including a plumbing code, a mechanical code, and an electrical code. However, most U.S. electrical construction is commonly governed by NFPA 70: National Electrical Code, published by the National Fire Protection Association under the auspices of the American National Standards Institute (ANSI).

Since the national model codes are purely advisory, a building code must be put into effect by local ordinance. While local building codes are usually based on the model codes, they often contain local modifications, which may be unnecessarily restrictive. Such re- strictions, along with delays in updating local codes, result in increased building costs. An- other problem associated with building codes at the local level is the quality of code administration. The lack of an adequate number of technically qualified building officials often leads to cursory inspections using a checklist approach and discourages contractors from utilizing new materials and procedures.

In most cases, a building permit must be obtained before construction of a building can begin. After a permit is issued, the local building department will inspect the project at designated points during construction. The scheduling of these inspections may pose prob- lems for the contractor and often results in construction delays. When utilities are not avail- able at the construction site, additional permits may be required for power plants, water wells, water treatment plants, sewage treatment plants or septic tanks, and similar facilities.

Zoning, Environmental, and Other Regulations

Although building codes apply only to building construction, many other regulations im- pact both building and heavy construction. Such regulations include zoning regulations, en- vironmental regulations, safety regulations, labor laws, and others. Transportation construction (highways, bridges, airports, and ports) falls primarily under the jurisdiction of state transportation departments. These agencies are responsible for the design, con- struction, maintenance, and operation of transportation facilities. While much of the design and most construction is accomplished by private firms under contract to the state, the state transportation agency establishes design specifications, monitors design and construction, and operates and maintains the completed facilities.

Zoning regulations, which control land use, limit the size, type, and density of struc- tures that may be erected at a particular location. Some typical zoning classifications include commercial, residential (with specified density), industrial, office, recreational, and agricul- tural. Zoning classifications are normally designated by a combination of letters and numbers. As an example, the R-4 zoning classification might represent residential housing with a max- imum density of 4 units per acre. In order to construct a facility not conforming to the current zoning, it would be necessary to obtain a change in zoning or an administrative exception.

Environmental regulations protect the public and environment by controlling such factors as water usage, vehicular traffic, precipitation runoff, waste disposal, and preserva- tion of beaches and wetlands. Large projects, such as new highways and airports, waste

10 CHAPTER 1

disposal facilities, major shopping centers, large industrial plants, large housing develop- ments, and athletic centers, may require preparation and approval of an Environmental Im- pact Statement (EIS) describing and quantifying the effect the project will have on the environment. The preparation of an EIS is a complex, time-consuming, and expensive task which should be undertaken only with the assistance of a professional experienced in such matters. If municipal utility services are not available at the project site, additional permits may be required for water treatment plants, wells, sewage treatment, and similar facilities.

Safety regulations are designed to protect both construction workers and the public. In the United States, almost all industries, including construction, are governed by the Occupa- tional Safety and HealthAct of 1970 administered by the Occupational Safety and HealthAd- ministration (OSHA). However, states are permitted to adopt more stringent safety regulations if desired. Construction safety is discussed in more detail in Section 1–5 and in Chapter 19.

The construction profession is also regulated by a number of governmental licensing and certification procedures. Communities having building departments usually require construction contractors to have their professional qualifications verified by licensing or certification. This may be done at the local level or by the state. State certification or li- censing often requires satisfactory completion of a comprehensive written examination plus proof of financial capacity and verification of character. A business or occupational li- cense is also normally required of all contractors. In addition, bonding is often required of construction contractors to further protect the public against financial loss.

1–4 STATE OF THE INDUSTRY

Construction Productivity

U.S. construction productivity (output per labor hour), which had shown an average annual increase of about 2% during the period after World War II until the mid-1960s, actually de- clined between 1965 and 1980. During the same period, inflation in construction costs rose even faster than inflation in the rest of the economy. However, indications are that con- struction productivity again increased substantially in the 1980s and 1990s (reference 1).

Concerned about the effects of declining construction industry productivity in the 1970s on the U.S. economy, the Business Roundtable (an organization made up of the chief execu- tive officers of some 200 major U.S. corporations) sponsored a detailed study of the U.S. con- struction industry. Completed in 1982, the resulting Construction Industry Cost Effectiveness (CICE) Study is probably the most comprehensive ever made of the U.S. construction indus- try. The study identified a number of construction industry problems and suggested improve- ments in the areas of project management, labor training and utilization, and governmental regulation (see references 5 and 8). It concluded that while much of the blame for industry problems should be shared by owners, contractors, labor, and government, many of the prob- lems could be overcome by improved management of the construction effort by owners and contractors with the cooperation of the other parties. Conflicting productivity data for the pe- riod 1979 through 1998 makes it difficult to determine whether construction productivity has actually declined, remained constant, or increased since 1979 (reference 9).

Some techniques for improving construction productivity and performance are dis- cussed in the following sections and in Chapter 20.

INTRODUCTION 11

Reducing Construction Costs

Some of the best opportunities for construction cost savings occur in the design process even before construction begins. Some design factors that can reduce construction costs in- clude the use of modular dimensions, grouping plumbing and other equipment to minimize piping and conduit runs, incorporating prefabricated components and assemblies, utilizing economical materials (eliminating “gold plating”), and employing new technology. Inject- ing constructability considerations into the design process is one of the advantages claimed for the use of the construction management contract arrangement.

Some ways in which productivity can be increased and costs minimized during con- struction include:

• Good work planning.

• Carefully selecting and training workers and managers.

• Efficiently scheduling labor, materials, and equipment.

• Properly organizing work.

• Using laborsaving techniques, such as prefabrication and preassembly.

• Minimizing rework through timely quality control.

• Preventing accidents through good safety procedures.

1–5 CONSTRUCTION MANAGEMENT

Elements of Construction Management

The term construction management may be confusing since it has several meanings. As ex- plained earlier, it may refer to the contractual arrangement under which a firm supplies con- struction management services to an owner. However, in its more common use, it refers to the act of managing the construction process. The construction manager, who may be a con- tractor, project manager, superintendent, or one of their representatives, manages the basic resources of construction. These resources include workers and subcontractors, equipment and construction plant, material, money (income, expenditure, and cash flow), and time. Skillful construction management results in project completion on time and within budget. Poor construction management practices, on the other hand, often result in one or more of the following:

• Project delays that increase labor and equipment cost and the cost of borrowed funds.

• High material costs caused by poor purchasing procedures, inefficient handling, and/or loss.

• Increased subcontractor cost and poor contractor-subcontractor relations.

• High insurance costs resulting from material and equipment loss or damage or a poor safety record.

• Low profit margin or a loss on construction volume.

12 CHAPTER 1

Such poor management practices, if long continued, will inevitably lead to contractor failure. While the principal objectives of every construction manager should be to complete

the project on time and within budget, he or she has a number of other important responsi- bilities. These include safety, worker morale, public and professional relations, productiv- ity improvement, innovation, and improvement of technology.

The scope of construction management is broad and includes such topics as con- struction contracts, construction methods and materials, production and cost estimating, progress and cost control, quality control, and safety. These are the problems to which the following portions of this book are addressed.

Quality Management

It has long been recognized that in all construction projects steps must be taken to ensure that the constructed project meets the requirements established by the designer in the proj- ect plans and specifications. More recently, the terms quality management (QM) and quality assurance (QA) have been adopted to include all aspects of producing and accept- ing a construction project which meets all required quality standards. Quality management includes such activities as specification development, process control, product acceptance, laboratory and technician certification, training, and communication. Quality control (QC), which is a part of the quality management process, is primarily concerned with the process control function. Since the contractor has the greatest control over the construction process, it has been found that quality control is most effective when performed by the contractor.

Regardless of the procedures established, the construction contractor is primarily re- sponsible for construction quality. Quality assurance inspections and tests performed by an owner’s representative or government agency provide little more than spot checks to ver- ify that some particular aspect of the project meets minimum standards. Contractors should realize that the extra costs associated with rework are ultimately borne by the contractor, even on cost-type contracts. Poor quality control will result in the contractor gaining a rep- utation for poor work. The combined effect of increased cost and poor reputation often leads to construction company failure.

In recent years, there has been an increasing use of statistics-based methods for qual- ity assurance, particularly in asphalt and concrete pavement construction (see reference 3). While the details of such procedures are beyond the scope of this book, the following is a brief explanation of some of the concepts involved.

Since the results of virtually all construction processes are products which vary over some statistical distribution, statistical methods can be used for such purposes as:

• Ensuring that all elements of the work have an equal chance of being included in test samples.

• Verifying that test samples taken by the contractor and by other parties come from the same population.

• Analyzing the variations in the test results of material and processes sampled.

• Establishing acceptable levels of variation in sample results.

• Developing a payment schedule which rewards or penalizes the contractor depend- ing on the level of quality attained in the constructed product.

INTRODUCTION 13

Safety and Health

Construction is inherently a dangerous process. Historically, the construction industry has had one of the highest accident rates among all industries. In the United States, concern over the frequency and extent of industrial accidents and health hazards led to the passage of the Occupational Safety and Health Act of 1970, which established specific safety and health requirements for virtually all industries, including construction. This act is admin- istered by the Occupational Safety and Health Administration (OSHA). As a result, man- agement concern has tended to focus on OSHA regulations and penalties. However, the financial impact of a poor safety record is often more serious than are OSHA penalties.

While specific hazards and safety precautions are presented in succeeding chapters and described in more detail in Chapter 19, the following construction operations have been found to account for the majority of serious construction injuries:

• Concrete construction, especially construction of formwork, placing concrete into formwork, and failure of formwork during construction.

• The erection of prefabricated trusses, precast concrete elements, and structural steel.

• The construction and operation of temporary facilities including scaffolding, con- struction plants, lifts, and storage facilities.

• Working from elevated positions resulting in falls.

• Construction equipment operations.

Construction managers should give special attention to the control of the safety hazards de- scribed above.

In the area of worker health, the major environmental hazards likely to be encoun- tered by construction workers consist of noise, dust, radiation, toxic materials, and extreme temperatures. Again, these topics are covered in more detail in Chapter 19.

Organization for Construction

There are probably as many different forms of construction company organization as there are construction firms. However, Figure 1–10 presents an organization chart that reason- ably represents a medium- to large-size general construction company.

Reasons for Construction Company Failure

Dun & Bradstreet and others have investigated the reasons for the high rate of bankruptcy in the construction industry. Some of the major factors they have identified include lack of capital, poor cost estimating, inadequate cost accounting, and lack of general management ability. All of these factors can be categorized as elements of poor management. Such stud- ies indicate that at least 90% of all construction company failures can be attributed to in- adequate management.

Use of Computers

The wide availability and low cost of personal computers have placed these powerful tools at the disposal of every construction professional. Construction applications of

14 CHAPTER 1

Figure 1–10 Representative construction company organization chart.

computers are almost unlimited. Construction applications of computers are discussed in more detail in Chapter 20. Examples of construction applications of personal computers are presented in the end-of-chapter problems of each chapter.

Perhaps the most exciting development in the construction application of computers is the wide availability of the Internet (World Wide Web) with its almost unlimited re- sources, along with electronic mail (e-mail) services. Equipment manufacturers are in- creasingly engaging in electronic communications with dealers and dealers with contractors. Contractors exchange information and data among projects and between proj- ect sites and the home office. Manufacturers are also providing online parts catalogs, as well as service and repair bulletins to dealers. Equipment warranty service requests are also being electronically processed. While some manufacturers’ information is available only to dealers and not to contractors, increasingly such data and services will become available to contractors. Electronic sales of new and used equipment and parts are also growing rapidly. In addition, much information of value to contractors is available on the Internet. Appen- dix C provides addresses for a number of construction Internet resources.

More traditional construction applications of computers include word processing, cost and time estimating, financial planning, planning and scheduling, project management, and

INTRODUCTION 15

1–6 CONSTRUCTION TRENDS AND PROSPECTS

Construction Trends

Some of the major trends noted in the construction industry in recent years include in- creasing international competition, rapid changes in technology, the wide availability of in- formation via the Internet, increasing speed and ease of communication, and increasing governmental regulation of the industry, particularly in the areas of safety and environ- mental protection. As a result of these developments, the larger well-managed construction firms are capturing an increasing share of the total construction market.

These trends, along with the increasing use of computers for design and management, have created a growing demand for technically competent and innovative construction managers. With the increasing automation of construction equipment has come an increas- ing demand for highly skilled equipment operators and technicians.

Problems and Prospects

In recent years, industry problems of low productivity and high cost have served to reduce construction’s share of the U.S. gross national product. This problem has been particularly acute in the building construction industry because the use of larger and more productive earthmoving equipment has served to keep earthmoving costs relatively stable.

Studies of international competition in design and construction have found that the U.S. share of the world’s market has declined significantly since 1975. During this pe- riod, foreign construction firms greatly increased their share of the U.S. domestic con- struction market. Despite these trends, many observers are confident that the U.S. construction industry will, over time, regain its predominant position in the world con- struction market.

Although high costs have often served to limit the demand for construction, during times of high demand the U.S. construction industry has actually approached its maximum capacity. When the demand for construction again peaks, it is probable that new forms of construction organization and management as well as new construction methods will have to be developed to meet these demands. In any event, the U.S. construction industry will continue to provide many opportunities and rewards to the innovative, professionally com- petent, and conscientious construction professional.

In summary, the future of construction appears as dynamic as does its past. An abun- dance of problems, challenges, opportunities, and rewards wait for those who choose to en- ter the construction industry. May the contents of this book provide the reader a firm foundation on which to build an exciting and rewarding career.