Handbook of cost data, for contractors and engineers; a reference book giving methods of construction and actual costs of materials and labor on numerous engineering works

Front matter

Class T/L M3_

Book iSlf/L__

COP^TRIGHT DEPOSm '

Preface

Four yeai-s ago I announced in my little book, "Economics of Road Construction," that I had in preparation a handbook of cost data for engineers and contractors. At that time this handbook had been under way for eight years, and it seemed nearly ready for publication; but other duties prevented a speedy finishing of the task. The delay, however, has been fortunate in that I have added very much to my knowledge of the general subject. In the meantime, two books have grown out of the original manuscript, namely, my books on earthwork and on rock excavation. The writing of these two books has better fitted me for the writing of this book, and has put me in touch with many engineers and contractors who have generously furnished additional cost data.

So far as I know, this is the first book on engineering cost data ever published. There are ''price books" written for house builders, but they are essentially what their name 4mplies — books on prices of materials and contract prices. This book differs from all such works, aside from the fact that it covers the whole field of civil engineering, in that it is a book in which costs are analyzed and discussed. A contract price is one thing, a contract cost is an entirely different thing, in spite of the common confusion of these terms. In order fully to understand any analysis of unit costs it is necessary to have a detailed description of the methods used in construction and operation. Hence, although itemized cost data occupy many scores of pages in this book, there are many more scores of pages devoted to descriptions of how the work was done, the organization of the forces, and the machines used. The records, in all cases, are actual records taken from every available source of published information, from personal letters sent by engineers and contractors and from my own records.

It is often said that cost data are of no value to an inexperienced man. Generally the men who make such stateiv PREFACE.

merits are themselves possessed of few records of cost, or use this argument as an excuse for not making public such records as they do possess. The very secretiveness of men having cost data which they refuse to make public, nullifies their statement that such data can be of no use to others.

We also hear it argued that conditions vary so widely that grave errors occur when an attempt is made to apply published cost data. Those who have not been trained to study the conditions affecting costs are likely to make serious blunders in any case; but, if this book is in even a slight degree what it aims to be, it will be of greatest benefit to just such men; for it will indicate to them how to analyze costs and how to study methods of performing work economically.

Many of the erroneous ideas about the value of cost recording arise from a confusion of the term cost with the term price. This is not a handbook of prices, although many prices are given. I could have filled ten volumes with prices, and with summaries of costs written by engineers who have failed to state rates of wages and conditions under which the work was performed. But, a short time after publication, all such matter is hardly worth the ink that it is printed with, since wages and prices are subject to constant change.

The attention of contractors is called to the first part of the book in which systems of cost keeping are described. I have outlined what I believe to be some of the best systems of cost keeping. Samples of other record cards and methods than my own are shown; for my purpose has been to elucidate principles, rather than to exploit pet theories as to business management and accounting.

HALBERT P. GILLETTE.

New York, Sept. 1, 1905.

Page SECTION I.— Cost Keeping, Preparing Estimates, Organization of Forces, etc 1

Objects of Cost Keeping... 1 Why Daily Cost Records are

Eexsential 3

Records Should Show Outputs of Individuals 4

Difficulty of Measuring

Dally Output o

Unit Method of Measuring

Output 6

Recording Output by Weighing 8

Record Cardg Attached to

Bach Piece of Work

Record Cards Used with a

Conductor's Punch 10

I se of a Mimeograph for Printing Record Cards. . . 12

Automatic Time Stamps 12

Time Cards and Time Books 13 Cards for Recording Materials Received 17

Use of Slide 'Rules and

Wage Multiplying Tables. 20 Recording Work by Minute

Hand Observations 20

How to Prepare Estimates

and Bids 25

Plant lExpense; Interest and

Depreciation 26

Cost of Fuel for Engines 29

Cost of Superintendence and

Percentage to Allow for Contingencies 29

Percentage to Allow for

Profits 30

List Prices and Discounts. 31

Insurance of Workmen 31

Schedule of Items of Cost. . 32

Unbalanced Bids 33

Causes of Underestimates.. 35

Page

Uniformity in Units of Measurement 37

Subletting Work and Purchasing Materials 38

Contract vs. Day-Labor

Work 40

Instructions to Superintendents and Foreman . " 42

Some Hints for Young Contractors 47

SECTION II.— Cost of Earth Excavation 73

E)arth Measurement 73

Earth Shrinkage 73

Kinds of Earth 74

Definitions of Haul and Lead 75

Work of Teams 76

'Cost of Maintaining Teams. 77,

Cost of Plowing 79

Cost of Picking and Shoveling 79

Cost of Trimming, Rolling,

etc 80

Cost of Wheelbarrow Work 81

Cost by One-Horse Carts. . 82

Cost by Wagons 83

Cost by Drag Scrapers 84

Cost by Wheel Scrapers 86

Cost by Elevating Graders. . 88

Steam Shovel Data 90

Hauling with Dinkeys 92

Summary of the Cost of

Steam Shovel Work 95

References 97

SECTION 111.— Cost of Rock Excavation, Quarrying and

Crushing 99

Weight and Voids 99

Measurement of Rock 100

Kinds of Hand Drills 102

Cost of Hammer Drilling... 103

Cost of Churn Drilling 105 vi