SCAFFOLDING - THE HANDBOOK FOR ESTIMATING and PRODUCT KNOWLEDGE

By Michael "Terry" Marks

Scaffolding is used in many industries every day, all over the world, in the construction industry; for commercial and industrial maintenance; the staging and entertainment markets; the shipbuilding industry; mining; industrial plants, including power plants; hydro and nuclear power facilities; pulp and paper plants; petrochemical plants; oil refineries; and offshore drilling rigs.

This book serves as a guide to any person involved with scaffolding in any way so that they will have a training and reference book that they can refer to for both scaffolding product knowledge and for estimating. The first ten chapters of this book include historical data and background information including product knowledge on all types of built-up scaffolding, suspended cradles, and swingstages. The eleventh chapter of this book is dedicated to the procedures that are used for estimating; preparing proposals, bids, and contracts, including systematic instructions on how to calculate the formulas that are most commonly used for estimating materials and labour outputs for scaffolding. Additionally, there are several sections of this book dedicated to temporary enclosures, built-up shoring and falsework, as well as manual and motorized suspended swingstages and cradles.

There are very few books available on these topics. To my knowledge there are none dedicated to product knowledge and the estimating of built-up scaffolding systems. No book can be all-inclusive, and this handbook does not claim to be. Much time and research has been put into this book to ensure that as many of the proven estimating methods and design concepts for all types of built-up and suspended scaffolding have been covered. Since one of our greatest assets in any business are our employees, the proper training of all craft and support staff within an industry is of primary importance. Additionally, the continuity in the training given to staff should always be kept up to a measurable standard and continually maintained to an acceptable level.

• Language: English
• Publisher: Page Publishing, Inc.
• Release date: Mar 25, 2021
• ISBN: 9781683483595

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Copyright © 2016 Michael Terry Marks

All rights reserved

First Edition

PAGE PUBLISHING, INC.

New York, NY

First originally published by Page Publishing, Inc. 2016

ISBN 978-1-68348-358-8 (Paperback)

ISBN 978-1-68348-360-1 (Hard Cover)

ISBN 978-1-68348-359-5 (Digital)

Printed in the United States of America

Table of Contents

Preface

Acknowledgments and about the Author

Introduction and History

Scaffolding Equipment

Scaffolding Design and Layouts

Tube and Coupler Scaffolding

Modular System Scaffolding

Sectional and Modular Frame Systems

Cradles and Suspended Swingstage Systems

Accessories and Temporary Enclosures for Scaffolding

Estimating, Proposals, and Contracts

Glossary of Terms

1

Preface

Scaffolding is used for numerous applications where scaffold platforms must be provided to insure safe working access whenever the work at hand can’t be reached from the ground. Scaffolding structures are erected and used every day of the week for all kinds of construction, demolition projects, and general infrastructure maintenance. Scaffolding is also used for maintenance in industrial plants, on restoration projects, for maintenance work on buildings, and for temporary protective enclosures around all kinds of structures. There are numerous types of scaffolding available with a variety of design configurations that are suited for just about any type of application or structure. Scaffolding is used in just about every major industry including all types of power-generating facilities, oil refineries, petrochemical plants, gas plants, offshore drilling and exploration rigs, pulp and paper mills, steel mills, mining, factories, food-processing plants, shipyards, film studios, stage and theater sets, sporting events, aircraft and aerospace facilities.

The purpose of this book is so that any persons involved with scaffolding in any way, in any industry, will have a reference book that they can refer to for scaffolding product knowledge and estimating. The first ten chapters of this book include historical data and background information with details on all types of built-up scaffolding and suspended cradles. The eleventh chapter of this book is dedicated to the procedures that are used for estimating, preparing proposals, bids, and contracts with systematic instructions on how to calculate the formulas that are most commonly used for estimating materials and labour outputs for scaffolding. Additionally, there are several pages dedicated to temporary enclosures, built-up falsework shoring, and manual and motorized suspended swingstages. There are very few books available on the subject of scaffolding, and to my knowledge, there aren’t any books dedicated to product knowledge and the estimating of all built-up scaffolding systems. No book can be all-inclusive, and this handbook does not claim to be; however, much time and research has been put into this book to insure that as many of the proven estimating methods for all types of built-up scaffolding have been covered. Since one of our greatest assets in any business is our employees, the proper training of all crafts and support staff within an industry is of primary importance. Additionally, the continuity in the training given to staff should always be kept up to a measurable standard and continually maintained to an acceptable level.

In England, where I first started my career in scaffolding, the training that I received early on from my fellow scaffolders and peers was excellent and has always proved invaluable to me. The rigging skills, the estimating procedures, and the layout and design techniques that I learned during my apprenticeship have been passed down through generations of scaffolding tradesmen and other operatives within the construction industry. In order to preserve this knowledge for many generations to come, I have compiled as much of this valuable information as possible into this book. As noted in this introduction, the book includes product knowledge and estimating formulas and procedures for all the following types of scaffolding systems and their related accessories.

1. Tube and coupler scaffolding

2. System scaffolding

3. Sectional frames, modular Euro-frame, and frames for shoring

4. Temporary enclosures

5. Manual and motorized suspended cradles and swingstage platforms

This handbook covers many aspects of scaffolding product knowledge, but the book is not intended to be a safety manual or an erection and dismantling manual. Wherever safety is mentioned or emphasized in this book, it cannot possibly cover all the rules and regulations for every possible application or for every particular geographical area. If you are designing or contemplating the use of scaffolding, this book can help you with the choices of scaffolding systems that may be available to you. Additionally, the book may help you with the concepts that are applied to the estimating of labour and the costing of the materials used on scaffolding projects. With the aforementioned points on safety in mind, it is very important to note here that all scaffolding must be designed and erected in compliance with your local governing safety rules and regulations, wherever you are.

If there is any doubt on the integrity of any scaffolding design, you should never hesitate to seek sound advice from a professional engineer or other suitably qualified person that is experienced in this field. Similarly, with the scaffolding systems and components, if you are unsure of the system or of a particular component’s capability, you should contact the manufacturer or the supplier to obtain technical specifications and safety data for the products at hand. All scaffolding products should have some kind of traceability to the origin of their manufacture. In the event that the supplier of a scaffolding system is unknown and the integrity of the system or any of its components are in question, the system must be evaluated or tested by competent persons that can certify that the products are in compliance and acceptable to all local safety standards. Whenever you are designing, working on, or using scaffolding for any purposes, please always remember this simple statement: SAFETY IS NO ACCIDENT . Think about this statement very carefully because it takes continual training, thinking, participation, and effort from the entire team to create and maintain an accident-free environment.

Since there are so many safety rules, codes of practice, regulations, and governing bodies for scaffolding around the world, it would require several volumes of books to cover them all. Before proceeding with any scaffolding projects, it is highly recommended that you obtain copies of all your local safety standards, as well as the rules and regulations in your particular area or establishment. Most countries will have very specific standards with safety rules and regulations for scaffolding and for working at height, which should be available through the government agency that regulates the occupational health and safety for the workplace in your area. Several countries have national standards institutes that offer publications that specifically cover scaffolding. Scaffold trade associations are also very good resources for obtaining up to date local safety rules and regulations, as well as other related working at height information. Government agencies, standards institutes, and trade associations can easily be found on the Internet these days. In the event that you cannot find adequate information on any scaffolding standards for your area, you may want to try contacting some of the following organizations that have standards that are recognized internationally. Since the addresses for some of these entities are subject to change, the websites that were active at the time of publishing are also noted.

In North America, you may contact the American National Standards Institute, commonly referred to as ANSI.

The scaffolding publication name is ANSI-A10.8 (+ current year) Scaffolding Safety Requirements.

American National Standards Institute

11 West 42nd St.

New York, NY 10036

USA

www.ansi.org

Alternatively in the USA, you may contact Occupational Safety and Health Agency commonly referred to as OSHA. Publications are under Codes of Safe Practice in the OSHA Standards Part 1926, OSHA Part 1910, and OSHA Part 1915 including all subparts.

United States Department of Labour

Occupational Safety and Health Agency

200 Constitution Avenue, NW

Washington, DC 20210

USA

www.osha.gov

In the United Kingdom you can contact the British Standards Institute, commonly referred to as BSI. The BSI publications include standards for Great Britain and all the European Economic Community (EEC). BSI publications include, but are not limited to, BS 5973 Access and Working Scaffolds and Special Structures in Steel, BS 5974 Cradles, BS 5975 Falsework BS 1139 and EN 74 on Metal Scaffolding. In June 2004 the EEC introduced a new scaffolding standard entitled BS EN 12811-1. This new standard does affect the BS 5973 standard. More recently TD-20 and the Working at Height rules have gone into effect. For more up to date information on any of these standards, you should contact BSI directly at the following address.

The British Standards Institute

389 Chiswick High Road

London W4 4AL

United Kingdom

www.bsi-global.com

At the time of publishing this book, the previously mentioned publications included some of the most comprehensive and up to date coverage on scaffolding standards that I have seen anywhere. Some of these standards are updated periodically. Therefore, it is very important that you keep in contact with these or your own local organizations in order to keep your information up-to-date.

Scaffolding associations are the eyes, ears, and the voice for the scaffolding industry. It is very important for all companies that are involved with scaffolding, in any way, to join and support their local scaffolding associations. Membership in a scaffolding association will give you a voice within your own industry and will help you to keep up-to-date on any new regulations and developments within the industry. Here is some information on the North American Scaffold and Access Industry Association, also known as the SAIA, and the United Kingdom National Access and Scaffolding Confederation (NASC). These two associations have the largest membership of scaffolding companies and professionals in the world.

The SAIA, or the Scaffold and Access Industry Association

The SAIA is the scaffolding association for North America, which includes Canada, the United States, and the Caribbean Islands but also has several members from many other countries around the world. This association has an open membership to all companies and professionals with an interest in the scaffolding industry. The SAIA has a large North American membership with several regional chapters that meet on a quarterly basis. This association also has a national conference and exposition every July. The SAIA publishes and circulates to their members a monthly magazine, an annual membership directory and some other useful publications. At the time of publishing, the head office for this association was at the following address.

Scaffold & Access Industry Association, Inc.

400 Admiral Blvd

Kansas City, MO 64106

Phone: [phone]

Fax: [phone]

www.scaffold.org

The NASC—National Access and Scaffolding Confederation of the UK

The NASC is the scaffolding association for Great Britain. This association has a very large membership that accounts for approximately 70 percent of the scaffolding industry workload in Great Britain. The NASC circulates a newsletter, an annual directory and several other useful publications. At the time of publishing, this association’s head office is in London at the following address.

National Access and Scaffolding Confederation (NASC)

4th Floor

12 Bridewell Place

London

EC4V 6AP

Tel: [phone]

Fax: [phone]

www.nasc.org.uk

2

Acknowledgments and

about the Author

This book is dedicated to my teacher and mathematics professor, Mr. John Ridd, who inspired me to get into some sort of engineering career; also, to one of my best friends Dennis Wu, one of the best Cradlehands in London in the 1960s to the 1970s and the man who taught me to be a Cradlehand. Also, I would like to acknowledge my first chargehand, David (Sully) Jacques, who was responsible for bringing me into the scaffolding game; to all the management that believed in me and helped me along the way in my career including Leonard and Robert Safier of Patent Scaffolding; David Webb and Neil Woods of SGB: Jeff Ott and Marc Wilson of Safway Steel Products. Thank you to all the great scaffolders, chargehands, foremen, supervisors, engineers, management, and owners whom I have worked with along the way. To all the great scaffolding and steeplejacking firms that I have worked for including; Scaffolding, GB Ltd. (SGB), Peter Cox Ltd., Hi-Lo Scaffolding, Stevens and Carter Scaffolding, D & R Scaffolding, Norstel Scaffolding, Steeplejack/Waco®, SGB Construction Services USA, Patent Scaffolding (HARSCO), and Safway® Steel Products. Thank you to all the companies that are mentioned in this book that may have provided any pictures, drawings and artwork used to complete the illustrations and samples used in each chapter.

The author, Michael T. Marks, started out in London, England, in 1967 as a scaffolding labourer/apprentice where he became a chargehand scaffolder and steeplejack. The author moved to San Francisco in 1973 and has worked in the scaffolding and steeplejacking business as a scaffolder, scaffolding foreman, supervisor, manager, vice president, and owner in the USA until this day. The author has trained many scaffolders, foremen, supervisors, engineers, sales staff, and managers, and it was one of the author’s ambitions to write this book to pass on the knowledge that is contained here.

3

Introduction and History

Scaffolding of some kind has been used as a means of temporary access and falsework for all kinds of intricate structures ever since man first decided to build higher than he could reach. This trend is not new and can be traced far back into the history of mankind. The English word for scaffold and its language root origin can be traced back over 1,700 hundred years with several Latin, Norman, Old North French and Middle English spellings. For example, in Middle English 1100 to 1300 AD, scaffold was spelled skāfõld or s-kā-fõld. The word skāfõld was derived from the Norman skæfèld and old North French word éscafaut or é-sca-faut, which translated into English literally means a raised platform or stage. Stage or staging is still a term that many English speaking people use for a scaffolding platform around the world. In modern French the words échafaud and èchafaudage have also evolved from their earlier Latin root words for scaffold and scaffolding respectively. The Old North French word éscafaut is believed to have originated from the Latin or Vulgar Latin word catafalicum (Proto Old English 300–500 AD). Variations of the word catafalicum or catafalcum are also seen a number of times in Medieval Latin as in faltum, scadafale and scafaldus, then again later in Anglo Latin as escafautium, scaffaldum and scafotum. The name Catafalicum is made up from two words cata and fala. The first part of the word cata is from the Greek word kæta that is used in many words as a prefix with meanings such as down, in position, to throw, raise and ascend. The second part of the word falcum or falicum is from the Latin word fala meaning tower. Several variations of these words for skāfõld have been modified throughout the Middle Ages to arrive at the modern day pronunciation and spelling of word scaffold or scaffolding. From the Middle Ages onward, several written references can be found for these words and other words used for scaffolding. Many references can be found in the old building records and in the fabric rolls from some of the oldest cathedrals in the world. These words all lead a trail to the modern-day spelling of scaffold and scaffolding. It is also of interest to mention here that the older English and Norman words skāfõld, skæfèld, skafoldyng, scaffotes, scafelys, scaffaut and scaffoldage have all evolved to their present day spelling and pronunciation of the singular word scaffold and its plural word scaffolding, similarly to the words found in the French language, with reference to èscauf, èscafaut, èchafaud and èchafaudage.

For thousands of years man has been building monuments and structures, some of which would have challenged some of the engineers and builders even of today. Some historic projects would have been difficult even with the aid of modern equipment and technology. Many historic structures were built with the aid of some kind of scaffolding, supporting falsework and winches. The scaffolding and falsework for some ancient structures would have to have been extremely strong in order to carry the huge loads that were imposed upon them. Many of the great Cathedrals of the Middle-Ages were constructed with large arches and domes, many of which would have required intricately designed timber falsework. As far back as 2000 to 2500 BC, the Egyptians were building pyramids, monuments and other structures out of stone and granite blocks. The size of some of the blocks used for some of these structures would have taken an amazing amount of support while being set into place. The transportation and placement of these stone blocks must have been quite an engineering fete. All over the world man has left his mark in many places throughout history. Artifacts have been found in ancient structures with early construction scenes painted or etched on tombs and some inscribed on to the walls of caves. Some of these remains clearly illustrate the history of the early masons and artisans of a bye-gone time. There are inscriptions shown on artifacts in many museums that clearly show people working on scaffolds and trestles, some with platforms spanned across them.

Several references are noted throughout England to the purchase and the use of timber scaffolding in the various fabric rolls of the great cathedrals of the Middle Ages. Some of these references can still be found and seen at cathedrals such as Durham, Exeter, and York. In the fabric rolls of Exeter Cathedral, the archive records refer to purchases of large poplar trees for scafoldyng and for cutting rods for the making of hyrdlles (hurdles) and flekes, the hurdles are referring to trestles or platform support bents.¹ Some of these records clearly state the materials used and thus, the methods applied for the erection of the scaffolding. Further translation from the Exeter Fabric Rolls refers to the scaphalda (scaffolding), which had standardes (vertical standards) that were of rough trees. References are also noted to hemp rope ties called twitchyngropes, which were used to tie withes together and were tightened down with warokkes. The withes were shorter length timber poles that were used for putlogs and transoms and a warokke was a wedge with a windlass that was used for tightening the hemp ropes ties, which were called twitchyngropes. In the building records at the Monk’s dormitory at Durham Cathedral c.1401, Scaffaldes, Seyntrees and Flekes are mentioned there in the indenture records.

There are many recorded historical details of scaffolding being used during early construction such as those found on Egyptian paintings and inscriptions dating back over 3,000 years. One example is clearly shown on the Tomb of Rekhmere c.1450 BC. This inscription clearly illustrates early craftsman at work standing upon the wooden pole scaffolding that was erected around the statue of the Pharaoh. The scaffold landing elevations on this wooden pole scaffolding, judging by the height of the men shown working, appear to be similar to the heights as those used today. Many of the great European Cathedrals and Castles that were built throughout the Middle Ages still bear the marks of the original putlog transoms that were used on the wooden pole type of scaffolding. Notre Dame Cathedral, Durham Cathedral, York Minster, Exeter Cathedral, and many other historic structures, all have inserts that were placed along the masonry walls upon removal of the timber putlog transoms. The wooden putlogs that were used in those days were lashed to the outside timber ledgers that were supported by the timber pole standards; the inborn end of the putlog rested right on the masonry coursework. This type of scaffold is referred to as a putlog scaffold. From this explanation it is easy to establish the source of the name putlog scaffold that is still used today, it literally means to place or put a log onto the masonry coursework to be used as a transom bearer. Previous to developing the first tubular steel scaffold coupler, the founder of SGB,² Mr. Daniel Palmer-Jones, had first designed a steel chain fitting that was used for lashing timber poles together. This chain fitting was called the Scaffixer Pole Clamp, which was patented and introduced to the construction industry in 1909. At that time, this new fitting was touted to be the most innovative lashing method available for tying timber scaffolding poles together. This fitting was used on some very ambitious timber pole-scaffolding projects of that era including the construction work at Buckingham Palace, which was done by Leslie & Co Ltd., in 1913.³ According to the contractor of record, the scaffixer chain lashing proved invaluable during the construction work at this project. This was due in part, to the very large loads that were imposed upon the rigging derricks, loading towers, and the access scaffolding, all of which were constructed from heavy timber poles.

fig 3

Fig 3.1 Buckingham Palace, London in 1913⁴

Although there was some experimentation with steel pipes as early as 1895, it was not until the turn of the twentieth century that steel scaffold tubes and couplers began serious development. The first steel scaffold couplers, which were used with steel water pipe at that time, were patented and introduced in Great Britain around 1910. Even after the introduction of steel couplers and tubing, as late as the 1940s, some scaffolds were still being built with wooden poles tied with hemp lashings. The Chinese and some of the other Asian cultures have been using bamboo poles to build scaffolding for thousands of years.

India and China are now among the largest producers of steel scaffolding and shoring in the world. With this more modern techniques for of scaffolding and falsework are now widely used in construction throughout Asia. This being said, bamboo is still used quite often for scaffolding in Hong Kong and in other cities throughout China and other Asian countries. During the past fifty years, there have been very few changes made in the way the bamboo scaffolding is designed and erected. The methods used for bamboo scaffolding have remained very similar throughout China for centuries. Today, even in modern cities such as Shanghai and Hong Kong, you may still see some high-rise buildings being constructed with both steel and bamboo scaffolding standing side by side. One of the few changes seen on these bamboo scaffolds is in the tying methods applied today. The use of synthetic rope and steel tie-wire are now widely used for tying the bamboo poles together. These man-made materials have virtually replaced the bamboo shard fibers and rattan strips of the old days. In Great Britain and throughout Europe, round and square wooden poles were used for scaffolding for hundreds of years. The wooden poles were tied together with hemp lashings and chains, which were tightened to the poles with wedges by means of a shingling hatchet as shown in the adjoining picture. The rigging skills employed to build these wooden pole scaffolds came from the shipwrights, carpenters and stonemasons that built the early castles and cathedrals throughout the middle-ages and were passed down the years from father to son and from tradesman to apprentice. Scaffold erectors of today are still using some of the early rigging techniques and skills that were employed back then, as well as the terminology that was used by some of these tradesmen, for hundreds of years.

Before the introduction of tubular steel scaffolding the bamboo poles that were used in many parts of Asia proved an excellent choice of materials to use for scaffolding. Bamboo has great strength and flexibility. It is recorded that typhoons have literally blown buildings down and the bamboo scaffolding has stayed together fully intact and still attached to the remains of the building. Today, however, materials such as bamboo, excluding China, and rough sawn wooden poles have for the most part become obsolete throughout the modern construction industry. This is due in part to practical reasons, but mainly because of the much stricter codes of safety and building regulations that are applied and enforced within the industries of today. The picture of the bamboo scaffolding illustrated above was taken in Hong Kong and this scaffold stood over 200 ft (60 m) in height.

hist_hatchet

During the last 130 years the scaffolding industry has grown from a handful of small specialty companies into a large global industry. This is due primarily to the industrial revolution and to the huge growth in construction of the infrastructure to support the huge world population explosion during this period. Other contributing factors to the rapid growth of the scaffolding industry are. (a) Much stricter safety laws, which are enforced throughout the entire construction sector and other industries. (b) The availability of more specialized raw materials allowing much more structural predictability of the scaffolding components. (c) Modern building regulations, codes of safe practice and last, but not least, public safety and general liability.

The United Kingdom, North America, Europe, and Asia are among the largest manufacturers, consumers and end-users of steel scaffolding in the world. There are now many companies around the world specializing in the design, manufacture and the erection of all types of scaffolding and shoring. The earliest registered scaffolding company known is believed to be Tasker and Booth Ltd.

This Company was registered around 1860 in London, England. In the last two decades of the Eighteen Hundreds other companies began to emerge that were specializing in the business of access scaffolding. In 1880 Edwin J. Palmer⁵ started the Palmers Scaffolding Company. Palmers Scaffolding in their early days, similarly to Tasker and Booth, specialized in wooden pole scaffolding and cradle access, now also known as swingstage. Before getting involved with scaffolding, Edwin Palmer was a Master Mariner by profession and with his vast knowledge of ships rigging and tackle, he designed the first traversing suspended cradle platforms, which were called traveling cradles. The earlier version of the traveling cradle was a very basic a wooden box platform with steel stirrups. These cradles were suspended from snatch blocks and fall-ropes that traversed using sheave pulley’s that ran along a steel cable like the one shown in the next picture of Edwin Palmer, whom is actually standing on the traversing cable.

hist_hatchet

Edwin J. Palmer later designed and introduced the first traversing cradle monorail track system. This was achieved by utilizing steel i-beams or rolled steel joist, RSJ,⁶ for the monorail tracks. The tracks were attached to wooden outrigger jibs using beam shackles that attached to the top flange of the joist track. This type of cradle system was known for many years as the Palmers Traveling Cradle. This type of cradle traverses along a structure using rolling sheave blocks, also known as jockey blocks.⁷ The monorail tracks could be placed for a single area drop or joined together along the entire length of a structure. The rolling blocks would traverse the track by pulling a tagline, also called a lightline, from inside the cradle. This tagline would go from the cradle through a small stop-end pulley that was attached to each end of the monorail track and then connected back to the rolling jockey blocks; this setup is explained in more detail in the chapter on cradles. Palmers Scaffolding⁸ are still in business today, which makes Palmers one of the oldest surviving scaffolding brand names in the world. Up until the late 1960s, cradles were still hung from either parapet clamps or counterweighted outrigger jibs that were built up with a wooden pole fixing resting on the roof or parapet ledge. The wooden pole roof frame and the outrigger jibs were fastened together with soft wire rope lashings.

The older style cradle platforms were made up with two steel stirrups that attached to a box like platform of varied widths and lengths. The basic design principles of the roof rigging and the cradle platforms have changed very little in the past hundred years. The swingstage platforms that are used today are obviously much more improved and sophisticated. Modern swingstage platforms are suspended by steel wire ropes that are raised and lowered using manual winch’s, electric and air driven hoist motors. Many of the platforms that are used today are modular in design and are made from aluminium and steel. Some monorail tracks are still made up from steel I-beams; however, today high strength structural aluminium beams are the preferred choice for monorail track. Similarly to the built-up type scaffolding systems, suspended cradle platforms have also been used on structures in some form or fashion throughout history. In the fabric rolls of York Cathedral and Windsor Castle, credills and swingyng scaphalda, cradles and swinging scaffolds, are mentioned for the repair work during their construction.

For as long as ships have been sailing the seas suspended cradles and bosun chairs were used for repairs and maintenance on the sides of these ships and vessels. Isambard Kingdom Brunel, 1806 to 1859, was among the greatest engineers of the industrial revolution era; he is shown in the adjoining picture standing next to the Great Eastern ship’s massive anchor chains at the Millwall⁹ shipyard in East London. Brunel designed and built many famous railways, rail bridges, railway stations, tunnels and ships during the 1800s. Many of his projects needed complex scaffolding and falsework, which he was responsible for designing on some of his projects. One of Brunel’s first projects was working for his father, Sir Marc Brunel, on the Thames Railway Tunnel, which was built under the River Thames in East London between Wapping and Rotherhithe between 1824 and 1843. Some of the falsework required for the Thames tunnel was quite complex for its day and required very detailed engineering. It is said that the erection of this falsework was supervised by Isambard Brunel personally. The Great Eastern ship, also known at that time as the Great Leviathan, was also designed by Isambard Kingdom Brunel and was built by the engineer and iron-ship designer John Scott Russell. The ship was built in East London at a site adjacent to the Millwall shipyard, on the Isle of Dogs in circa 1850.¹⁰¹ During construction of the Great Eastern ship, the picture above clearly shows the use of cradles as well as the access scaffolding seen on the keel of the ship. The Great Eastern was the largest ship ever built at that time; it measured 689 ft (210 m) in length and 82 ft (25 m) across. The ship was so long that it had to be built parallel to the river in order to launch it.

Up until the late 1960s, scaffolders in Great Britain were still taught to do the roof rigging for cradles with soft wire rope lashings and wooden poles. The wire lashings were tied by hand and then tightened up using a shingling hatchet as shown in the adjoining picture, which we called a cradle hammer. Most of the timber pole tying and rigging techniques that were used for cradle rigging were similar to those utilized for hundreds of years on the built-up timber pole scaffolds. In the UK the scaffolders that were trained to do the rigging and erection of cradles were also called cradlehands. During the last quarter of the twentieth century, proprietary outrigger beam systems and the more modern scaffolding systems had pretty much replaced the old wooden pole fixings that were previously used for the roof rigging of cradles. Some of the newer buildings and structures of today are designed with permanent roof fixings, such as davits, permanent eyelets and permanent monorail systems, which are sometimes built right into the roof, or attached to the outside of the upper structure or under the building soffits. Scaffolders and cradlehands referred to cradles, and to any type of suspended swingstage platforms, as boats. This nickname came about because the rigging and the concept of a cradle is almost identical to that of a ships lifeboat. Lifeboats on ships, similarly to all suspended cradles, consist of a small boat suspended from two cantilevered yardarms, or from outriggers and davits, with two single purchase sheave-blocks, two fall-ropes and a tagline.

Fig 3

Fig. 3.2 End View of Build-Up Cradle Pole Fixing and Roof Saddle

Wooden poles tied together with soft wire lashings were used to form all kinds of roof fixings, some quite straightforward and others extremely complex. Some of the more complex fixings on apex and dormer roofs had to be built up as high as 30 ft (10 m) just to support the outriggers, which sometimes had to be cantilevered out over the roof parapet or roof ledge. This type of rigging is called a build-up fixing and is illustrated in figure 3.2. Some apex roofs, especially on some of the older buildings, had inclines as steep as 60 degrees, some with double mansards and dormer windows projecting out of the roof. This type of roof would entail the rigging of a wooden pole roof saddle that positioned and supported the built-up cantilevered outrigger jibs, which were all tied together with soft wire lashings. The erection of a build-up fixing without damaging the roof was quite a feat in itself, especially when a roof was built out of biscuit thin slate tiles, thin copper or lead sheets. On many of the older buildings there were always many obstacles to overcome and contend with, some of the older roofs had huge brick chimneys, as well as large decorative balustrades with ornate copings around the entire perimeter of the roof line. The wooden pole rigging for some of these very complex built-up roof fixings was a real art, requiring the rigging skills of very well trained cradlehands.

The rigging and knot tying skills of some of these craftsmen was tremendous. Many of the knots¹¹ used to tie any two poles together, when they were tied correctly they had no half hitches or granny knots to finish the knot ends. After the lashings were tightened down to the poles with a cradle hammer, the ends of the lashings on the ties were double-turned around in between the two pole connection joint and then tucked back between the lashing turns and the timber pole; this type of tying method was known as a nip and tuck tie. Tying of the knots properly was very important because of the swelling of the wooden poles due to dampness, rain and other changes in weather conditions. If the lashings were tied incorrectly they would sometimes have to be cut through with the hatchet side of the cradle hammer upon dismantling the rigging. The proprietary scaffolding and roof accessories that are now available for suspended platforms take far less rigging skills than the poles and lashings of the old days. Some of the roof designs on the older and on some unusual structures still require some very intricate rigging, therefore it is still important to preserve and teach some of the older rigging skills and techniques. Even with the aid of modern equipment it is sometimes necessary to incorporate some of the old rigging principles with the modern technology in order to get the job done correctly.

Most of the terminology used by scaffolders and cradlehands for all the various scaffolding components and applications has been passed down through the ages. Many of the scaffolding terms originated from various parts of ships rigging, some of the terms came from the early joinery carpenters, shipwrights and stonemasons. Some of the words used for specific scaffold members such as ledger, standard, transom, spur or sparre, outrigger, jib, needle beam, bridle, splice, raker, brace, puncheon, soldier, scarf, hemp and truss have been around on ships for centuries. Up until the late 1800s many sailors, especially the ship riggers and carpenters, were regularly employed between voyages to erect the wooden pole scaffolds that were used in construction for hundreds of years. Sailors and ships boatswains with their vast knowledge of rigging and knots proved invaluable at this trade and with their early contributions of the rigging methods, and much of the terminology, formed a solid basis that is still used in the scaffolding industry today. Learning all the terminology, and what the various terms mean from a structural standpoint, is a very important part of the scaffolder’s apprenticeship. For example, in the UK when a scaffold is erected using tube and coupler scaffolding, the scaffold gang, which usually consists of three men, upon unloading their truck they quickly identify and sort from a pile of assorted sizes of tubing each scaffolding part by name; i.e., transoms, ledgers, standards, braces etc. This may not seem very important; however, on complicated projects, such as cantilevers or hanging scaffolds, the communication of the correct terminology for all the scaffolding components is very important. Although some size tubes may be used for more than one purpose on a particular job, the ground man will know exactly what that part is being used for when an erector calls down for something by name. Let us say that a scaffold gang is erecting a truss-out or a cantilevered scaffold and 16'0 (4.9 m) tubes are being used on five different parts of the scaffold; the 16 ft tubes could be used for the ledgers, puncheon standards, outrigger needles and for knee braces or spurs. Although the erector could simply call down for a 16'0 (4.9 m) tube, when the erector calls down for a spur or a puncheon, the ground man knows exactly what tube must be sent up to the erector in specific way; for example, a spur or knee brace may be sent up with a right angle coupler and a safety check coupler already attached at the top end of the tube. Similarly, a puncheon standard would be sent up with the right-angle coupler upside down with a safety check coupler set directly above it at the bottom end of the tube. Since the erectors may be sitting out on the cantilever outrigger needles way up in the air, the communication of the correct terminology becomes extremely important. There are many nicknames used for rigging and for scaffolding components and items in general. A list of scaffolding terminology and definitions is included in the glossary at the end of this book. The first ten chapters of this book will concentrate on product knowledge that will identify, describe and explain the uses of most of the equipment that is used today for built-up access scaffolding as well as some information on 10-kip shoring and falsework.¹² Product knowledge, good training and proper design are the keys to providing SAFE ACCESS solutions for all scaffolding applications. Whenever you are stumped on an unusual design always remember that there is not a structure ever been built that cannot be safely accessed by some type of scaffolding. One only has to look back at the history of all architecture to realize that this is a fact. Knowledge, experience and creativity are the keys to solving most complex access problems.

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1 A bent is another word that is sometimes used in place of a transom or a putlog bearer.

2 SGB is short for Scaffolding Great Britain, which was originally registered as Scaffolding, GB Ltd., and is now part of the Brand Energy Group.

3 The picture of Buckingham Palace shown in figure 3.1 was provided compliments of SGB London, UK

4

5 Picture of Edwin Palmer provided compliments of Palmers Scaffolding, Chandlers Ford England

6 Rolled Steel Joist were also called RSJ’s by scaffolders and cradlehands.

7 Aptly named because when a sheave block traverses a monorail it resembles the up and down motion of a jockey riding a horse.

8 At the time of publishing, Palmers Scaffolding was owned by the ThyssenKrupp Group of Companies.

9 Millwall, which is also known as the island or the Isle of Dogs, is in East London and is now well known globally as Canary Wharf , because it is one of the largest world banking centres.

10 ¹ Information provided by courtesy of the National Maritime Museum London, England.

11 Most of the knots used to tie the wooden poles together were either square knots or parallel knots.

12 10-kip (aka 10-K) shoring is referring to shoring that is rated with a safe working load of up to10,000 lbs (4,535 kg or 44.5 kN) per leg, which includes a 2-1/2 to 1 safety factor.

4

Scaffolding Equipment

Scaffolding products used over the past hundred years

Ever since the first tubular steel scaffolding was introduced, there have been many improvements to the various product designs that have strongly contributed to more precise and measureable safety of tubular steel and aluminium scaffolding. Starting as early as the turn of the nineteenth century, several patent applications were submitted for various scaffold fitting designs that were to be used with steel tubes for the purposes of built-up tubular scaffolding. Patents were also applied for on a steel chain bracket coupler that could be used for attaching wooden poles together. Between 1895 and 1925 a whole variety of new design ideas were proposed for tubular scaffolding by some of the early company founders of the steel scaffolding industry. Some innovative ideas were proposed and brought forth by some of the most well known civil and structural engineers of the industrial revolution era.

The forerunner to the first bolt-up style steel coupler, which was successfully being used on an ongoing basis, was being developed as early as 1906 in England. In 1916 the Universal Scaffolding Coupler, as shown in figure 4.1, was patented by one of the founders of SGB, Mr. Daniel Palmer-Jones. The earlier universal coupler designs underwent various improvements between the years 1906 to 1915 before it was finally completed and patented. This load-bearing fitting was a three-part tube impinging friction coupler that consisted of a hand-forged body called a band, a screw-plate and friction chair. The coupler was widely known throughout the scaffolding industry as the band and plate and proved to be an excellent design for several applications. This coupler could effectively be used for any right angle connection as well as a parallel connection of any two tubes. The unique design of the band allows the connection of a diagonal tube to a horizontal tube. Additionally, the band and plate could be used as an unobstructed transom coupler. It was because of its versatility, and its multi-purpose ability, that the band and plate was originally named the universal scaffolding coupler.

Fig. 4.1 Universal Band and Plate Coupler

In the early days of steel scaffolding, couplers were used to connect 2 in (50 mm) OD heavy-gauge black steel water pipes together. This type of heavy water pipe was used right up until it was replaced by tubing that was specifically designed for scaffolding purposes. Another scaffold fitting, which was developed by SGB around the same time as the band and plate, was the DH coupler as shown in figure 4.2. The DH coupler is a non-load bearing fitting that has many practical uses for scaffolding. The DH was named as such because it worked well to connect and position any two tubes together in both the diagonal and the horizontal positions.

Fig. 4.2 DH Coupler—Diagonal and Horizontal Single Coupler

The DH was most commonly used for attaching the outside ends of transom bearers to the ledgers and the bottom end of an internal diagonal brace connection to a ledger. The DH coupler was also used to attach fascia sway bracing on to the ends of transoms at intermediate intervals in between standards. By using a DH coupler on the outer end of a transom bearer to ledger connection, the DH made an excellent toeboard guide, the DH also worked very well as a toeboard clip. This type of tubular scaffolding system was known throughout Great Britain as Tube and Fittings and although the band and plate and the DH fittings are not that often used these days, tube and coupler scaffolding is still referred to the same name in the UK today.

It is of interest to note here that in 1906 Mr. Daniel Palmer Jones and Mr. David Henry Jones had started their own company called the Patent Rapid Scaffold Tie Company. This same company continued successfully during this period and around 1920 was renamed the Tubular Scaffolding Company, Ltd. By 1922, this company became public and was again renamed Scaffolding (Great Britain) Ltd, this company is still known internationally as SGB. From a small plant hire firm in 1906, SGB¹³ are now one of the largest scaffolding, shoring and formwork companies in the world, with a network of branch operations and dealers on every continent. By the mid to late 1920s, steel tube and coupler scaffolding began to appear throughout other countries in Europe and in the United States. In the early 1920s, Patent Scaffolding, then of Long Island City, New York, became the earliest adopters of tubular steel scaffolding in the United States. Since Patent Scaffolding had started up in 1909, by 1920 they were already well established in the United States with their proprietary Gold Medal Suspended Scaffolding Machines. Patent were very instrumental in the early growth of tube and coupler scaffolding throughout the United States and Canada. Patent designed, developed and manufactured their own unique brand of tubular scaffolding that they named Tublox. Until the year 2000 the Patent division of Harsco Corp had one of the largest branch networks in North America, with operations in the United States, Canada, Mexico and Puerto Rico. In the year 2000, Patent’s parent, Harsco Corporation, acquired SGB and since then has acquired Hunnebeck and ESCO with combined operations throughout Africa, Australasia Asia, Europe, the Middle East, North, Central and South America and between them now has one of the largest scaffolding, shoring and formwork networks in the world, all doing business as