Scaffolding

by A. G. H. Thatcher

London: February 1904.

NOTE TO THE SECOND EDITION

Recent alterations in and additions to the legal enactments affecting scaffolding and the persons employed in its erection have rendered necessary a second edition of this work. The author has accordingly revised the information relating to the law of the subject, and has embodied the important series of suggestions for the guidance of those engaged in building operations, published in the Annual Report of the Chief Inspector of Factories, which, if followed out, will undoubtedly be the means of reducing the number of fatal and other accidents occurring at such works.

A. G. H. T.

October 1907.

CONTENTS

PAGE
Preface	[v]
CHAPTER I
SCAFFOLDING
Scaffolding—Definition of—Northern system—Derrickstagings—Working platforms—South country system—Gantries, commonly called travellers—Travelling gantry—Gantrieswhich serve as a base for lighter forms ofscaffolding—Stagings—Pole scaffolds—Bricklayers’scaffolds—Masons’ scaffolds—Connections	[1]-29
CHAPTER II
SCAFFOLDS FOR SPECIAL PURPOSES
Needle scaffolding—Scaffolds for chimney shafts,towers and steeples—Domes and arches—Swingingscaffolds—Painters’ boats—Boatswain’s boat—Ladderscaffolds—Supported painter’s boat	[30]-48
CHAPTER III
SHORING AND UNDERPINNING
Shoring—Flying shores—Raking shores—Underpinning	[49]-61
CHAPTER IV
TIMBER
Classification and structure—Defects in the livingtree—Felling—Conversion—Seasoning—Description—Selection—Decay—Preservation—Durability—Use of scaffolding timber	[62]-75
CHAPTER V
CORDAGE AND KNOTS
Cordage—Strength of—Knots	[76]-89
CHAPTER VI
SCAFFOLDING ACCESSORIES AND THEIR USE
Ladders—Trestles—Cripples—Buckets andskips—Baskets—Barrows—Stone bogies—Handbarrows—Hods—Timber trucks—Sack trucks—Crates—Ashlarshears—Stone clips and slings—Stone lewises—Stonecramps—Wire and chain scaffold lashings—Tighteningscrews—Rollers—Levers—Dog irons—Bolts—Straps—Wireropes—Chains—Slater’s truss—Duck runs—Mortarboards—Wedges—Nails—Spikes—Scaffolder’s hatchet	[90]-114
CHAPTER VII
THE TRANSPORT OF MATERIAL
Crane engines—The crane—Pulleys—Differentialpulleys—Winch—Jibs—Shears—Gin—Rails—Sacktrucks—Attachment of material—Ironwork—Timber—Bricks—Slates—Stone	[115]-130
CHAPTER VIII
THE STABILITY OF A SCAFFOLD
Stability—Wind pressures—Force of weight or gravity—Tofind the centre of gravity of a body—Two or morebodies—Of a dependent scaffold and the effect of loadsupon it—Of a gantry—Of a Scotch derrick	[131]-142
CHAPTER IX
THE STRENGTH OF A SCAFFOLD
Failure of beams—Pillars and struts—Ties andtraces—Dead loads—Live loads—Breaking weight—Safeload—Constants—Beams subject to a transversestrain—Posts and struts subject to compression—Bracesand ties subject to a tensional strain	[143]-153
CHAPTER X
THE PREVENTION OF ACCIDENTS
Short ladders—Sagging of ladders—Guard rails—Wellholes—Edge boards—Traps—Runs—Supports to centering—Dampcordage—Sound material—Competent control—Fan guards—Duecare by workmen	[154]-160
CHAPTER XI
LEGAL MATTERS AFFECTING SCAFFOLDING
Scaffolding bye-laws—Burgh Police (Scotland) Act—Factoryand Workshop Act, 1901—Abstract of same, issued fromthe Home Office—Notice of Accident Act—Report onBuilding Accidents by a Home Office Inspector—Workmen’sCompensation Act, 1906—Application of Act and definitions	[161]-178C
Appendix: Weight of Material	[179]
Index	[183]

LIST OF ILLUSTRATIONS

PLATES
[I].	Derrick staging	Frontispiece
[II].	External chimney scaffold	Facing p.33
[III].	Knots	79
[IV].	Knots	81
[V].	Knots	85
[VI].	Knots	87
ILLUSTRATIONS IN TEXT
FIG.		PAGE
[1].	Elevation of staging for derrick crane	4
[2].	Plan of king leg	6
[3].	Showing shoring to central standard	6
[4].	Plan of derrick platform partially covered	7
[5].	Showing method of fixing ladders	8
[6].	Showing derrick staging mounted on travelling bogie	10
[7].	Elevation of square derrick staging	11
[8] and [8A].	Elevation of gantry for traveller	13
[9].	Footing blocks for struts	15
[10].	Elevation of travelling gantry	15
[11].	Gantry or elevated platform over footpaths	17
[12].	Example of stagings	18
[13].	Elevation of pole scaffold	20
[14].	Method of fixing rising standard	21
[15].	Method of connecting ledgers	22
[16].	Method of connecting ledgers	22
[17].	Method of connecting ledgers	23
[18].	Method of connecting ledgers	23
[19].	Method of supporting putlogs where windows occur	24
[20].	Method of supporting putlogs where windows occur	24
[21].	Shores and ties for dependent scaffolds	25
[22].	Methods of laying boards	26
[23].	Methods of laying boards	26
[24].	Masons’ scaffold: end elevation	27
[25].	Landing stages	28
[26].	Needle scaffold	31
[27].	Internal chimney	33
[28].	Method of climbing chimneys, steeples, &c.	35
[29].	Method of climbing chimneys, steeples, &c.	36
[30].	Brackets for climbing chimneys, steeples, &c.	37
[31].	Methods of slinging painters’ boats on chimneys, &c.	38
[32].	Chimney scaffolds for repairs, &c.	39
[33].	Details of chimney scaffolds for repairs, &c.	39
[34].	Details of chimney scaffolds for repairs, &c.	40
[35].	Details of chimney scaffolds for repairs, &c.	40
[36].	Details of chimney scaffolds for repairs, &c.	41
[37].	Method of supporting standards within high towers	41
[38].	Scaffold designed for repairing roofs or archeswhere roadway has to be kept open	42
[39].	Painters’ boats or cradles	43
[40].	Method of slinging cradle to move horizontally	44
[41].	Improved painter’s boat	44
[42].	Boatswain’s boat	45
[43].	Elevation of ladder scaffolding	46
[44].	Details of ladder scaffolding	47
[45].	Details of ladder scaffolding	47
[46].	Details of ladder scaffolding	47
[47].	Examples of flying shores	51
[48].	Examples of single raking shore	52
[49].	Examples of system of raking shores	53
[50].	Details of raking shores	54
[51].	Details of raking shores	55
[52].	Details of raking shores	56
[53].	Example of underpinning	59
[54].	Example of window strutting	60
[55].	Example of cup shakes in timber	63
[56].	Example of radial shakes in timber	63
[57].	Method of cutting stiffest beam from log	66
[58].	Method of cutting strongest beam from log	66
[59].	Method of cutting planks from log	67
[60].	Method of stacking timber for seasoning	68
[61].	Examples of weather shakes in balks	68
[62].	Method of strapping ends of boards	74
[63].	Details of ladder construction	91
[64].	Details of ladder construction	91
[65].	Example of painters’ trestles	92
[66].	Example of cripples	93
[67].	Example of cripples	93
[68].	Example of tipping pail	94
69.	Details of improved safety baskets	95
[70].	Details of improved safety baskets	95
[71].	Details of improved safety baskets	96
[72].	Details of improved safety baskets	96
[73].	Details of improved safety baskets	96
[74].	Example of navvy’s barrow	98
[75].	Example of stone bogie	98
[76].	Example of hand barrows	98
[77].	Example of labourer’s hod	98
[78].	Example of timber trucks	98
[79].	Example of sack trucks	98
[80].	Example of brick crates	99
[81].	Example of ashlar shears	100
[82].	Example of ashlar shears	100
[83].	Example of stone clips	101
[84].	Method of slinging stone	101
[85].	Method of slinging stone	101
[86].	Method of hoisting by means of the lewis	102
[87].	Method of hoisting by means of the lewis	102
[88].	Method of hoisting by means of the lewis	102
[89].	Method of hoisting by means of the lewis	102
[90].	Example of the stone cramp	103
[91].	Wire rope lashing	104
[92].	Chain and bracket lashing	105
[93].	Coupling links	105
[94].	Rollers	106
[95].	Levers	106
[96].	Dog irons	107
[97].	Methods of fixing dog irons	107
[98].	Methods of fixing dog irons	107
[99].	Methods of fixing dog irons	107
[100].	Iron bolts	108
[101].	Iron straps	109
[102].	Slaters’ truss	112
[103].	Duck runs	112
[104].	Scaffolder’s hatchet	113
[105].	Manual building crane	117
[106].	Example of pulley wheel	118
[107].	Example of groove for pulley wheel	119
[108].	Example of groove for pulley wheel	119
[109].	Example of groove for pulley wheel	119
[110].	Example of groove for pulley wheel	119
[111].	Example of groove for pulley wheel	119
[112].	Example of sprocket wheel	119
[113].	Example of single movable pulley	120
[114].	Example of blocks and tackle	120
[115] and [116].	Example of differential pulley	122
[117].	The winch	124
[118].	The winch in use with a double rope	125
[119].	Example of a jib	125
[120].	Example of a jib for fixing purposes	126
[121].	Example of a mason’s jib	127
[122].	Example of shear legs	127
[123].	Example of shear legs to carry jib	128
[124].	Example of movable shear legs	128
[125].	Example of a gin	129
[126].	Method of slinging girders	129
[127].	Diagram showing method of finding the centre ofgravity of a rectangular body	136
[128].	Diagram showing method of finding the centre ofgravity between two combined weights	137
[129].	Diagram showing method of finding the centre ofgravity between three or more combined bodies	138
[130].	Method of finding the centre of gravity of arectangular surface	139
[131].	Method of finding the centre of gravity of atriangular surface	141
[132].	Diagram showing the method of calculating the breaking weights of beams	147
[133].	Diagram showing the method of calculating thebreaking weights of beams	147
[134].	Diagram showing the method of calculating thebreaking weights of beams	148
[135].	Diagram showing the method of calculating thebreaking weights of beams	148
[136].	Diagram showing the method of calculating thebreaking weights of beams	148
[137].	Diagram showing the method of calculating thebreaking weights of beams	148
[138].	Diagram suggestion for preventing accidentson short ladders	154
[139].	Method of staying ladder to prevent sagging	155
[140].	Method of staying ladder to prevent sagging	155
[141].	Illustrating dangerously laid boards	156
[142].	Illustrating the danger of a trap	156
[143].	Illustrating method of supporting centering	157
[144].	Illustrating method of supporting centering	158
[145].	Fan guards	158
[146].	Illustrating cause of fatal accident	159

SCAFFOLDING