IMIA Working Group Paper WGP 80 (13) IMIA Conference New ......strength and the low cost of bamboo. No machinery is needed to assemble the scaffold and it can be easily adjusted to

IMIA Working Group Paper WGP 80 (13)

IMIA Conference New Delhi, 21st to 25th September 2013

Formwork and Scaffolding Collapses Working Group Members: Alon Eisenberg, Engineers, Surveyors & Loss Adjusters, Modiin, Israel Richard Gordon, Infrassure Ltd, Zurich, Switzerland Patricia Marzullo, Fairfax Brasil Seguros Corporativos S/A, São Paulo, Brasil Chairman: Martin Frey, Amlin Re Europe, Zurich, Switzerland Sponsor: Max Benz, XL Insurance, Zurich, Switzerland

IMIA WGP 80 (13) Formwork and Scaffolding Collapses P a g e | 2 __________________________________________________________________________________________

TABLE OF CONTENTS

Subject Page 1. Executive Summary: ........................................................................................ 3

2. Introduction and Motivation: ............................................................................. 3

3. Definition of Scaffolding and Formwork ........................................................... 4

3.1. The Evolution of Scaffolding and Formwork..................................................... 4

3.1.1. Scaffolding ...................................................................................................... 4

3.1.2. Shoring and Formwork .................................................................................... 5

3.2. Types of Scaffolding, Shoring & Formwork ...................................................... 6

3.3. Prices and Depreciation .................................................................................. 9

4. Insurance Aspects of Formwork and Scaffolding ........................................... 10

5. Examples of Formwork and Scaffolding Losses ............................................ 14

5.1. Predominant Loss Types ............................................................................... 14

5.2. Baileys Crossroads Building .......................................................................... 16

5.3. New York Coliseum, 1955 ............................................................................. 16

5.4. Bridge Falsework Collapse ............................................................................ 17

5.5. Motorway Viaduct Collapse ........................................................................... 19

5.6. A scaffolding Collapse – John Hancock Center in Chicago, 2002 .................. 20

5.7. A comment on Employers Liability ................................................................. 20

6. Best Practice Formwork and Scaffolding temporary Work Procedures. ......... 24

6.1. Legislation ..................................................................................................... 24

6.2. Temporary Works procedures ....................................................................... 25

6.3. Works and Management of the Key Risks Elements ..................................... 25

6.4. Consequences of the Risks involved in Formwork and Scaffolding ............... 25

6.5. Safe Implementation of Formwork and Scaffolding Schemes on Site ............ 26

6.6. Typical Organigram of Key Personnel for a “Temporary Works Team” .......... 26

6.7. Management of Temporary Works during the Construction Phase ................ 28

7. Conclusions: .................................................................................................. 31


1. Executive Summary: Collapses of formwork and scaffolding are occurring at a disturbing frequency. They are, however, only noted in the wider public when third party property is affected in a spectacular way or, tragically, when workers or pedestrians are injured or even killed. The main focus of this paper shall be on “Engineering Insurance” related aspects even though we are aware and respect that the Employers Liability dimension to the formwork and scaffolding industry has a much wider relevance in view of the immense cost and pain such accidents cause to workmen, third parties and their families.

After a brief overview of the basic technologies used, we will discuss insurance aspects and explain the typical challenges in assessing construction projects. The special insurance features and issues encountered in the claims adjustment process of formwork and scaffolding losses are described and best practice recommendations are given.

Several loss examples are illustrating and identifying typical loss scenarios and the devastating effects formwork and scaffolding failures may have on site – and how little it would take to avoid these.

The paper concludes with a chapter on best practice and will propose “concrete” steps to install a state of the art risk management procedure on construction sites.

2. Introduction and Motivation: Not a single construction project can be executed without the use of scaffolding and formwork. Sometimes, as Engineers, we may admire the courage and the skills of workers climbing to breath taking heights on scaffolds. At times, we may note the beauty of scaffolding structures or be impressed by the sheer size and complexity of the arrangements. Most of the time, however, we may consider scaffolds a nuisance because they block our way or sight.

As construction underwriters, we assess projects in great detail and depth. We check time schedules, bills of quantities, design criteria, new technologies, third party and Nat-Cat exposures to name just a few – but do we spend enough time on considering and managing the impact, scaffolding and formwork activities may have on the construction projects we insure?

Just google “formwork collapse” or “scaffolding collapse” and you will be amazed (eventually shocked) about the incredible number of postings and pictures your search will yield. Quite clearly, formwork and scaffolding collapses do occur at a surprising frequency. Why is it that there seems to be little attention paid to this aspect in the field of engineering insurance?

This paper tries to describe insurance related aspects of formwork and scaffolding techniques in a practical and “hands on” manner. Real life examples will be used to explain the typical loss scenarios. Building on these, we will discuss insurance aspects as well as risk management procedures and conclude with a set of recommendations. Our aim is to attract and raise our awareness as underwriters and risk managers to the many issues around formwork and scaffolding activities on construction sites. Our motivation is to help reduce injuries and losses. We hope your help enables us to succeed in this.


3. Definition of Scaffolding and Formwork When we started our work on the topic, we soon realized that it is very easy to create Babylonian confusion by using dozens of different expressions for almost the same (e.g.: false work, shoring, propping, staging…). In order to reduce the level of confusion to the bare minimum (we hope), we have chosen to only use the term “Formwork and Scaffolding” (F&S) going forward (except here in this chapter 3 which describes some standard types of F&S). Therefore, for the purpose of this paper, the term F&S stands for a temporary means:

1. On which workers may stand in order to perform their work 2. Which will carry and support the weight of the structure until it can hold itself 3. Which will be used for the containment of the concrete until it is hardened.

3.1. The Evolution of Scaffolding and Formwork

3.1.1. Scaffolding The use of scaffoldings made of timber or wooden beams has a history dating back several thousand years. The picture below shows an example of a drawing found in the tomb of Rekhmire, a governor of Thebes who lived in the 14th century BC in Egypt. It illustrates the use of scaffolds consisting of tall vertical and horizontal poles lashed together with ropes and planks providing walk-ways for stonemasonry workers.

Illustration of the use of scaffolds in the tomb of Rekhmire

In many countries in Asia, bamboo scaffolding is still common practice. This ancient method of traditional bamboo scaffolding is very effective and efficient due to the low weight, the surprising strength and the low cost of bamboo. No machinery is needed to assemble the scaffold and it can be easily adjusted to any shape (provided you have the necessary skills, of course).

Even for very modern and complex structures, bamboo scaffolds may be the right choice as illustrated on the next page.


Traditional bamboo scaffolding on complex structures

Introduced in the mid-1950s, the basic lightweight tube scaffolding (with the three main components tubes, couplers and boards) became the standard and has revolutionized the scaffolding industry. The tubes are made either of steel or aluminum – and these scaffolds are used in countless projects all over the world.

3.1.2. Shoring and Formwork One of the first and finest examples of skilful use of formwork to create a concrete structure is most probably the spectacular Pantheon Dome in Rome with a diameter of 43 meters (below). Believed to be built at the beginning of the second century AD, it has been admired throughout the ages till today.


The use of concrete and formwork applications dramatically increased with the invention of Portland cement in the early part of the 19th century. For many years, the traditional timber formwork as shown in the picture below was used.

Over the years, formwork systems have seen an amazing development: new materials such as metals, polymers and composites were introduced and a lot of effort was put into reducing the labour intensiveness of building up formwork structures, speeding up construction processes and reducing cost.

3.2. Types of Scaffolding, Shoring & Formwork It is obviously impossible to give a detailed outline on F&S systems in this paper. The following list should be seen as an attempt to provide a very basic description of the main types of F&S.

i. Working scaffolding & stair systems – Traditional scaffolding used for workers to stand on with guard rails and stairs between the levels.


ii. Shoring systems – Used to safely transfer the structure load to the supporting ground. Shoring systems are commonly made of steel or aluminium beams and or frames connected together into a supporting tower, a “load bearing tower” of 4 legs. In most cases it will require many supporting towers in order to support the structure weight. Most important are the diagonal bracing rods which create the tower strength.

iii. Framed formworks, Wall, Column, Floor & Slab formwork – The most common and

widely used formwork. It is made of large panels or frames of different sizes connected one to the other.


iv. Climbing formwork – This method is used in high rise structures such as buildings, communication towers, chimneys and similar structures that have a repetitive shape. The formwork is designed according to the shape of the structures and, once the first section of concrete is poured and has cured, will be elevated so that further segments can be constructed. The “climbing” is propelled by jacks or with the use of cranes.

v. Bridge formwork – Where traditional scaffolds are not applicable because of large spans or heights, specially designed and often very spectacular bridge formwork structures are used such as arch, launch travellers, balance cantilever and carriageways formworks.


vi. Tunnel formwork – Another example of a “moving” formwork, used for the application

of tunnel linings and mining works.

3.3. Prices and Depreciation Cost for formwork and scaffolding are often very small compared to the total project values. Whilst cost will of course vary substantially depending on the project, the following table may give an approximate range of cost involved in traditional F&S works.

Type Cost

General access scaffolding 50 Euro / m2

Shoring equipment for casting a 3.0 metre high ceiling

100 – 250 Euro /m2

Shoring equipment for casting an above 3.0 metre high ceiling

200 – 400 Euro /m2

Self climbing formwork for a 40 floors building with a core section of 500 sq/m2

2,000,000 Euro /system

Balance cantilever systems for bridge 400,000 – 500,000 Euro /system

Please note that the cost of a bamboo scaffold is only about 10% of the cost of a “traditional” steel/timber scaffold.

The ultimate aim for the contractor in selecting the most appropriate formwork system is not only the most cost effective solution, but also the most practical system that provides program


advantages, ease of use and speed, fulfils the safety and security standards and helps to mitigate potential risks.

Cost optimization considerations will also include the options of purchasing the equipment outright, hire or a combination of both. Some systems of formwork have versatile components which can be used on a variety of future projects. However, it is not uncommon on completion of a project for the materials to be scrapped in their entirety.

Some F&S-systems may require extensive use of cranes, which is a considerable cost factor on high rise developments. It is not uncommon to have hired equipment for the duration of a project only to return it and incur significant damage charges due to poor handling of the equipment. Purchasing equipment also means incurring cost for maintaining, storing and transporting it for future projects – which also can be linked with considerable expense.

Quite obviously, the choice of a formwork system is never an easy one and needs to take many specific factors into consideration!

4. Insurance Aspects of Formwork and Scaffolding

When we reviewed the insurance literature and Engineering publications available, we soon realized that the subject of F&S is not one which is described extensively. We have not been able to identify statistical information on F&S losses (other than in the Employers Liability segment, which we briefly touch upon at the end of chapter 5). Does this mean that the insurance of F&S is not posing any issues? Not quite, we tend to believe. Here are some of the questions (and our proposed answers).

A typical CAR or EAR policy wording usually states that:

• Cover is provided for property described in the schedule and used in performance of the contract

• For property incorporated in the final project and for temporary works or temporary structures

• For insured parties • Contractors’ plant and equipment (CPE) is usually excluded from the basic CAR/EAR

policy but can be insured by endorsement

Some critical questions:

• It is quite rare to find specific underwriting information on F&S in submissions for projects. Therefore, schedules are usually silent about F&S and, consequently, do not indicate values, sums insured or limits.

o Is it therefore correct to argue that F&S is not covered under a basic CAR policy when it is not “described in the schedule”?

o And what is the effect if a value for F&S is declared in the sum insured • We have already commented that it is impossible to complete any project without the

use of F&S. Hence, F&S are without any doubt “used in performance of the contract”. o Is this argument good enough to provide cover under a basic CAR Policy?

• What is meant with the expression of temporary work and temporary structures? o Does this include F&S?


• The definition of “the insured”. Engineering policies usually indicate the names of the most important parties to the project. The large number of additional parties (such as subcontractors or suppliers) is referred to as “all subcontractors” or “all other parties having an involvement in the project”.

o Is a scaffolding Company who supplies a scaffold as “hired in plant” an insured party?

o And: What happens if the scaffolding Company is called on site to modify the F&S in order to meet the requirements of the principal and other contractors?

o And: If the scaffolding company is listed as subcontractor, does this have any effect on the status of the scaffold “hired in”?

We have held many discussions with insurers, reinsurers and loss adjusters. All the above questions are very relevant – and have often been answered differently, depending on the complexity and the specific environment in which it is executed (including legal environment).

So: is there clear guidance on how F&S needs to be insured and under which section of the policy it is covered?

Let’s give it a try. The following section is a summary of a discussion on F&S issues with Rupert Travis, Executive Director of Cunningham Lindsey International Ltd. We hope that these explanations and the conclusions help underwriters in better understanding insurance related aspects of F&S.

We started the discussion with the question: “Are there any issues in dealing with F&S losses?”

The answer was that: “This is a common problem for decades. The argument is about: Are loss costs to be attributed to the categories “Plant” or “Temporary work”?

The confusing answer is: Both views can be OK!

There is a clear view “in theory”. In practice, most of the time a pragmatic solution is found, mainly because of the costs involved in settling F&S losses are comparatively small.

The theory would suggest that every F&S-loss occurring on site would have to be split up into the two categories “Plant” (which is normally excluded in a standard CAR policy unless it is added by endorsement) and “Temporary work” (which is usually covered under a basic CAR policy). The “Plant” part would pick up the losses to the material not incorporated in the final project whilst the “Temporary work” would pick up the erection cost (which is intrinsically linked with the project) associated with the loss.

Following on from this logic, the “Temporary work” part would be considered to be related with the project works and thus be indemnified under the CAR policy.

The “Plant” part would consequently be considered separately. In most cases, it would have to be picked up by the Insurance policy for “Plant”. This policy needs to be arranged for by the owner of the plant” (for instance an annual policy for the Company owning the equipment). As an alternative, insurance cover for “Plant” could also be given by endorsing the CPE cover to the CAR policy by adding a “CPE-Endorsement”.


The issue which needs to be clarified here is which party carries the risk of damage to “Plant” in the course of the project execution. This party is also responsible for arranging appropriate insurance cover (of course with a corresponding premium).

Some problems may occur in those cases where it is not clear whether parts are “of temporary works nature” or “Plant”. The test question for such cases is:

• If it is specifically built for the job, and has no residual value for use on another contract, at the end of the project, it is temporary work. The full value should be included in the project sum insured and – in case of loss, the CAR policy conditions will be applied in that loss adjustment process. The indemnification in case of loss is usually on full value (exceptions may apply if such equipment is damaged towards the end of the project (when it is already fully depreciated). In such situations, a good loss adjuster will consider the options to mitigate the loss and propose reasonable alternatives.

• If the equipment is “hired in” and reused, it is treated as “Plant” and indemnification according to “actual value” will apply.

• There are a number of situations where it is impossible to be 100% specific. Such situations exist when, for instance, the “nature” of the equipment changes from being “Plant” (when it is laying loose on the ground) to becoming “Temporary work” when erected.

• It should be noted that also “responsibilities” for the equipment may change. Whilst the scaffolding company is responsible for the supply of the equipment, the contractor will have the responsibility for it when it has assumed the nature of “Temporary work” when erected. But it is obvious that there are always periods of transition as that “change in nature” does not happen in a second.

The following recommendations may help to avoid unpleasant surprises and long discussions due to gaps in the insurance cover:

• Use clear definitions: The policy wording should be as clear as possible in respect of what is meant to be covered as “Temporary work” or by endorsement. We have seen examples, where it was clearly specified that F&S are to be considered “temporary work”, as the following example shows:

“It is specifically agreed that shuttering formwork scaffolding cofferdams sheet steel piling temporary fabrication yards temporary bridges and temporary roads on or around the Project Site for the purpose of performing the Project and not being permanent works shall be regarded as Temporary Works”.

This is even more important in the future because formwork systems are becoming ever more sophisticated (and expensive). Project schedules depend a lot on the proper functioning of such systems. Therefore, we can surely make the recommendation that a good definition of the term “Temporary work” is certainly a good basis to avoid unnecessary difficulties in the loss adjustment process. This is even more important in cases where ALOP covers are granted. For the ALOP cover to respond, it must be


triggered by a cause clearly covered by the policy. A missing Endorsement or an unclear definition may have expensive consequences and it will most probably be happening when you least expect it.

• In certain simple cases (particularly when smaller sums are involved), the “theoretically correct” method of splitting the loss into the two components may seem to be a bit too academic. Nevertheless, Underwriters should be reminded that, loss adjusters have the duty to settle the losses according to the strict meaning of the policy wording. Therefore, if the policy is silent or ambiguous, this is where the trouble starts.

• Where large quantities of “hired in” equipment are involved, it would certainly be prudent to clarify the ownership (and thus responsibility to insure) for these elements. The option to add a “CPE”-Endorsement to the CAR policy is certainly a good one (but it comes at a small cost, i.e. premium). Always check whether the parties involved are to be considered as “insured parties”. Check that adequate insurance protection is in place in either case.

• Depending on the quantities of F&S involved, the declaration of the correct sum insured is essential to evaluate and price the corresponding coverage. Cover extent may also differ considerably, depending on the basis of indemnity which will be applied. Specifically designed and expensive formwork systems further need to be assessed for their depreciation throughout the execution of the project. Some of the elements may be reused for other projects which renders the task of the loss adjuster even more complicated. More than ever, we strongly recommend working with experienced loss adjusters for such tricky cases.

Be aware that there is this unique “change in nature” of F&S equipment which does transform from being “Plant” to becoming “Temporary Work” and “Plant” again during the execution of the project.


5. Examples of Formwork and Scaffolding Losses A word about “missing stats”: Having consulted with many insurance companies and claims managers, we unfortunately found that there are no statistics for F&S losses available for the Material Damage section of CAR policies. From the claims examples in this section, you will soon realize that the majority of the cases can be typically explained by few root causes. Therefore, we start with the brief summary of predominant loss types.

5.1. Predominant Loss Types 1. Foundations – Inadequate foundation of the shoring systems. The shoring structures

are usually placed on the original ground without any improvement. The combination of poor and often inadequately surveyed ground conditions (or fill) and the load imposed lead to collapse.

2. Concrete properties – Engineers and construction workers consider the wet concrete as if it was dry. There is, however, a fundamental change of the properties of concrete from its liquid to its solid state. In addition, wet concrete is a thixotropic liquid! (Thixotropy = “liquidity depends on stress applied”) and, to make matters worse, after pouring of concrete, vibrating equipment is commonly used creating additional vibrating loads. Therefore, the loads of wet concrete are uneven creating a considerable lateral force on the bottom compared to the top of the formwork. When casting a slab over a span, the force is – depending on the rigidity of the form - concentrated in the middle section of the span creating a bending force on the supporting girders. The following sketch is an attempt to illustrate two typical situations in which the use of wet concrete may result in unexpected load distributions.

An artist’s impression of the different load diagrams of wet (green) and “ideal” elements of solidified (blue) concrete


3. Wind loads – Calculating a wind load on a high shoring or formworks is not a custom construction engineering practice. The wind load is a decisive influencing factor and estimating the wind pressure in addition to the dead load requires know-how and wind data that is not always available. Wind loads can be substantially increased by the use of dust protection, or advertisement posters attached to the scaffold

4. Fatigue – Fatigue of the shoring or formwork. F&S components are reused, handled and operated with little care and in rough working conditions, are often inappropriately maintained and possibly overloaded over time. Due to this, fatigue and undetected cracks reduce the load bearing capabilities below the designed specifications.

5. Faulty design – Faulty design of the shoring, formworks or scaffolding such as inadequate weight design, distances between shoring supports, lack of diagonal bracing, etc.

6. Faulty workmanship – The on-site construction workers do not follow the design or manufacturers requirements such as: reducing the number of shoring legs, inadequate connection or bracing of the equipment, inadequate assembly of the shoring or formworks, dismantling the shoring or formworks earlier than required in order to speed the works, overloading temporary structures with construction material, etc.

7. Shuttering and stripping – Mainly damage to the supporting equipment or third parties if it falls from the building during the shuttering (erection) and stripping (dismantling) of the shoring or formworks.


5.2. Baileys Crossroads Building Even though this is a very old case, it is a nice example for the devastating effects a small mistake in the handling of formwork may have. And at the same time, it is a good illustration for the “domino” effect which often creates surprising results (in the negative sense).

The progressive collapse of the middle portion on this 26-storey building in Baileys Crossroads in Virginia was caused by premature removal of formwork. It resulted in 14 fatalities and considerable damage and delay to the project.

Formworks were supported by floors which were at least 7-days old in the lower sections. The failure occurred on the 24th floor which was shored to the 5-day-old 23rd floor.

The weight of the rubble of the 24th floor overloaded the 23rd floor which failed in shear around one column, triggering a collapse that carried through the entire height of the building.

5.3. New York Coliseum, 1955

In 1955 the main exhibition floor of the New York Coliseum collapsed when concrete was being placed. Almost 1,000 m2 of floor area collapsed at once, injuring 50 workers and killing one.

The form of the floor was two stories high and supported by timber shores connected to a crossbeam. However, the crossbeam did not brace against lateral instability. Later, when 12 power buggies (each weighing some 1.5 tons) were driven across the formwork, they imposed a lateral thrust onto the deck. The lack of diagonal bracing members to transfer the lateral force caused the structure to sway and fail without warning.


5.4. Bridge Falsework Collapse

We use the term “falsework” for once. It is used for structures which combine the functions of Formwork and Scaffolding.

From the two previous cases, one could conclude that due consideration of lateral forces in falsework structures was a problem of the past, as it has become the standard in today’s construction industry. Not quite, unfortunately. The following case from 2009 in Poland where a partial collapse of a bridge under construction provides a good illustration for:

• The continued and widespread neglect of the appropriate consideration of lateral forces in falsework

• The fact that large quantities temporarily stored material are usually not considered in the design of falsework

• The tricky challenges to repair collapsed falsework

The falsework design (above) and the collapsed cross section of the bridge deck (below)


And the situation after the collapse:

The investigation revealed two factors contributing to the collapse:

• The main cause was (once more) the lack of bracing to adequately counter lateral forces. • Large quantities of reinforcing bars were temporarily stored on the bridge deck. These bars

have imposed a load which was not considered in the original falsework design.

The repair works were considerably complicated by the fact that substantial weight lifting operations were necessary to rectify this “small” dislocation.


5.5. Motorway Viaduct Collapse

This collapse occurred on a Motorway construction project in Portugal in 2010. The viaduct under construction was spanning a motorway in operation. The collapse occurred during the pouring of concrete (860 m3 of a total of 1,300 m3 were already poured). The whole length of the fresh concreted section of the deck, together with its supporting structure collapsed at once.

Luckily, the collapse happened during the evening when traffic on the road below was light. Tragically, the accident caused the death of a driver and has injured 8 workers.

The investigations concluded that the accident was caused by an uneven load distribution during the pouring of the concrete for the deck. The cost for the material damage section was estimated to be € 600,000 (ALOP was not insured).


5.6. A scaffolding Collapse – John Hancock Center in Chicago, 2002

This spectacular and well known case did not occur during the construction case of the project but after its completion. We nevertheless include it in our collection of examples because it is an impressive demonstration of the severe consequences a small oversight may have with regards to third party liability.

The scaffold platform was suspended by two outriggers on the roof of the building, and on the day of the collapse, the north outrigger overturned and fell to the ground below. The south outrigger remained intact, causing the scaffold platform to swing back and forth along the west facade of the building. When this happened, the scaffold broke multiple windows of the John Hancock Center and the debris from the scaffolding structure fell onto East Chestnut Street below.

Three motorists were killed by the falling scaffold pieces and several other people were injured. At the time of the collapse, there were no workers on the scaffold platform due to the inclement weather conditions (speeds of 35 mph with gusts of up to 56 mph). High winds caused the contractor to suspend work for the day, and the scaffold platform was being stored approximately half way up the building when the collapse occurred. It was determined that many factors contributed to the collapse of the scaffolding, including design and procedural errors by multiple parties.

The scaffold collapse at the John Hancock Center caused the code to change in the city of Chicago with respect to scaffolding design and safety.

5.7. A comment on Employers Liability

The focus of this paper is on F&S insurance aspects which are relevant for the Engineering insurance industry. Despite this, we would like to add some remarks about an aspect which is very relevant for our liability underwriting colleagues. When reviewing the information available on the internet, there is a very strong focus on worker accidents and Employer Liability and Workers Compensation. Whilst this may be a surprise at first sight, the reasons for this are soon becoming clear: the vast majority of EL/WC cases are occurring in relation with F&S activities or use. It appears that F&S is the most dangerous activity and the source of an incredible number of accidents which take a horrendous toll on the health and even the lives of many workers. We have the hope that all the recommendations for a better managed F&S activity on site will have a positive knock on effect for the safety of the workers too.


As Engineering underwriters, we tend to focus a lot on technical “hard facts” in our assessment of a risk. Many of the accidents and losses happening on site are, however, man-made. An interesting study performed at the Swiss Federal Institute of Technology in Zurich provides a good insight on the stress-induced working conditions on site.

Even though the study is not focussing on collapses of formwork and scaffolding in the narrow sense of this Workgroup Paper, we believe that the “work system” (with its components “personnel”, “technology”, “work organisation”) analysed in the study may strongly influence the quality of the scaffolding and formwork. For sure, the findings of the study should give us some food for thought, well beyond the “Scaffolding and Formwork” topic: A Master Study by Elke Tomforde Schöni in 2007 Center for Organizational and Occupational Sciences, Swiss Federal Institute of Technology, Zurich Research topics include: Complexity of human work, Human interactions in their work processes, and psychology in work environments. “Work system and perception of stress in the scaffolding industry” The main focus of the study is how the organisation of work systems may influence health-related issues (in this particular case “perceived stress”) of workmen in the scaffolding industry. It is based on interviews conducted with scaffolders on various hierarchical levels in construction companies in Switzerland.

Key findings:

• Scaffolding work is (really) dangerous:

o Scaffolding is the segment with the highest accident rates in the construction industry. The frequency of “accidents” in pure scaffolding companies in 1995 was 372 per year per 1,000 workers! It was reduced to 250 accidents per 1,000 workers by 2005. (Since 2002, there is a specific apprenticeship for scaffolders in Switzerland, specific training on scaffolding for other construction apprentices were implemented, SUVA (the Swiss National Accident Insurance) is very active in prevention e.g. by broadcasting trailers on work safety on TV, advertisements (examples can be found on www.suva.ch), inspections on site and education.

• Scaffolding jobs are often subcontracted:

o Scaffolding Companies often use subcontractors for erection and disassembly of scaffolds and to cover peak periods. Subcontractors are often very small companies (average of 3.5 workers).

o Most of the subcontracts were concluded without a written contract!

• Qualification of workmen:

o Very tough job, generally low level of qualification, younger workers with little experience, often workers from abroad (1/3rd of the workers are foreigners). A lot of “on the job training” particularly in smaller companies and subcontractors. There is a clear link of the level of qualification of the workmen with the size of the company. Also, there is a clear link of the number of accidents with the level of qualification. Countermeasures: Specific Apprentice introduced in 2002. Trainings and controls were intensified, awareness campaigns were conducted.

o Many companies state that financial situation does not allow for training and development measures (also see financial pressure).

http://www.suva.ch/


• Work organisation:

o 2/3rd of scaffolding companies own their scaffolds and have 8.5 employees on average. The remaining 1/3rd are subcontractors without scaffolds and an average of 3.5 employees. They are often hired for erection and disassembly jobs. The proportion of part time workers is much higher in smaller companies.

o Work environment:

On average, a scaffolding worker carries/lifts 8.5 tons (max in excess of 11 tons) per day.

Often in difficult climatic conditions and with limited/difficult accessibility of the worksite.

Considerable time pressure (scaffolders are often the last in the information chain). Overtime and week end work is a frequent issue.

• Financial pressure increasing:

o The average cost of scaffolding per square meter is declining.

• Causes for accidents:

o Wrong or insufficient information (no “full picture”)

o Planning deficits due to lack of preparation, short term changes

o Insufficient level of qualification, misunderstandings (also due to lack of language skills)

o Low motivation (work conditions, perspectives)

o Unsuitable or damaged equipment

o No checks prior to use, no systematic checklists

o Unclear responsibilities, organisation.

So what are the lessons learnt from this study? There are many “matter of course” conclusions, really! Predominantly “stress induced by human elements” rather than technology are the drivers for accidents. If we accept that accidents of workmen are an indicator for the quality of work, it is fair to assume that there is a link to our topic of “Formwork and Scaffolding collapse”, too. The “human element” is a key issue we need to address! It’s not so much “what” you do, but “who” does it - and “how”. The scaffolding job seems to be much more susceptible to revealing “Quality-issues” than other construction jobs. Ironically, the author of the study also indicated some difficulties in her research work namely:

• Some companies went bankrupt in the course of the study

• No interest was shown due to time constrains (everybody was busy working on site)

• Language skills were not sufficient


• The “healthy worker” effect may lead to a positive bias of the results (the interviews could not be conducted with injured, old, dead scaffolders …)

We therefore will have to accept that some of the following points have a direct impact on the number of incidents with potentially disastrous consequences on site:

• Good (risk) management, appropriate planning and design of the job is key

• Know your partners. Qualified and motivated people are more expensive but cost less in the long run (an accident costs 27,000 Swiss Francs on average).

• Communication, teamwork. Make sure the “work system” is adequately defined. The more individual steps are split up or outsourced, the more interfaces needing control and potential errors are created.

• If you pay peanuts, you get monkeys.


6. Best Practice Formwork and Scaffolding temporary Work Procedures.

Main contractors generally classify F&S under the title of Temporary Works. The definition of which is a temporary structure required to construct a permanent or to support a permanent structure to the client’s specification.

For Formwork and Scaffolding systems to be successfully implemented they must be well planned, managed and monitored using best practice guidelines and procedures as well as experienced and competent personnel. This is to ensure that all reasonably practicable risks are managed and where reasonably practicable eliminated.

The following sections aim to give Insurers a greater appreciation of how we would expect the Insured to manage the safely manage these complex and technical processes on a construction projects which have a varying contract value. They have been developed and written with respect to the Main contractor having overall responsibility for delivering the project to the client’s specification. These can also be referred to as the Insured.

6.1. Legislation After reviewing worldwide F &S standards and requirement we have realized that Health and Safety regulations do vary throughout the world; however generally they enforce legislation with regards to the duty of care of the contractor i.e. what they must do to protect the safety of their employees and third parties. The design of Formwork is solely under the basis of engineering best practice and without any clear substantial design guidelines regarding to material damage. Insurers must take into account geographic location and main contractor experience. Nonetheless, we have seen examples where national trade associations issued guidelines and standards for a licensing scheme to improve working standards. In other cases, particularly losses of human life events, triggered government agencies to issue “best practice” safety memorandums detailing procedures going forward.

Of course it’s safe!!


6.2. Temporary Works procedures It is very important to have formalized procedures to manage Formwork and Scaffolding through their life cycle from conception, design, construction and removal. The procedures should detail the steps and the responsibilities of persons managing the process and the hold points requiring sign off before proceeding to the next stage. The first interaction would be to prepare a temporary works schedule for envisaged schemes of Formwork and Scaffolding. This would then be and classified under which elements could be delivered by in house Technical resources or which schemes fall under special categories requiring independent design and checking. These schemes may be typically classed as Major or Minor schemes. In the UK for example there is a British Standard document BS 5975:2008 which details for four categories and details recommended interdependence of the design check. As an insurer it is reasonable to expect that all professional organisations have these procedures in place as part of their quality assurance systems and accreditations.

Most construction projects require the need for Formwork and Scaffolding to safely deliver the permanent works to the clients end specification. As projects become more sophisticated, using ever developing new technologies of F&S, with challenging programme constraints, there is a need to ensure that the approach to temporary works schemes are controlled and well managed.

6.3. Works and Management of the Key Risks Elements Some key risk elements listed below are areas of potential risk that need to be accounted for and mitigated when evaluating schemes. Failure to do so may give rise to a significant issue that may cause significant physical, personal and financial damage.

• Poor design. • Use of unsuitable or insufficient materials particularly corroded fittings • Lack of knowledge and experience of personnel managing and installing. • Incorrect estimation of loads. • Design errors or modifications or changed sequence of events. • Inadequate maintenance. • Inadequate supporting foundations. • Incorrect transfer detailing for transfer of horizontal and vertical loading.

6.4. Consequences of the Risks involved in Formwork and Scaffolding Failure to manage and mitigate the potential risks as far as reasonably practicable may lead to physical, personal and financial damage. This could lead to the ultimate loss of human life and a considerable financial claim for property damage and equipment. Examples of real life losses and consequences were detailed in previous section of this paper. Main Contractors have legal obligations under Health and Safety Regulations to prevent the following:

• Risk to persons from collapsing structures onto them. • Risk to persons falling from collapsing structures. • Risk from falling materials onto personnel or members of the public. • Risk of damage to plant and equipment.


• Risk of damage to adjacent properties or assets such as Property- Buildings, Railways.

If any of the above scenarios were to materialize then under the legal system of the respective country key project personnel could be prosecuted through the respective legal system. Such events could lead to imprisonment of key personnel, significant financial penalties and loss of professional reputation of the company. This reinforces the need to work to agreed procedures to prevent such occurrences.

6.5. Safe Implementation of Formwork and Scaffolding Schemes on Site The insured must have in place set procedures that should be clear to follow, they must be managed rigidly at various stages from concept, tender and through to construction and removal. In order to follow these procedures, it is fundamental that key personnel are appointed to deliver safely and successfully.

6.6. Typical Organigram of Key Personnel for a “Temporary Works Team”


A) Company Temporary Works Manager The company must appoint a person who has the requisite qualifications, professional experience and competency. They would also have sufficient resources available to them to ensure all the requirements are met. These appointments are usually made by senior persons in the organization usually Operation to Managing Directors. The temporary works manager would have the following responsibilities.

• Overall responsibility that schemes are undertaken as per procedures. • Ensure that design organizations have the correct personnel. • Appoint a Temporary works coordinator. • Liaise and advise, demonstrate knowledge, experience and understanding • Audit and monitor the Temporary works procedures. • Identify training needs and implement accordingly. • They could be based on site or at head office dependent on scope of works, visiting site

periodically.

B) Temporary Works Coordinator This person is appointed by The Temporary Works Manager and is usually site based. They will be responsible for site specific schemes and be responsible for authorizing of the loading and unloading of schemes.

• They will prepare and manage the schedule of Temporary works and monitor progress • Coordinate with external Design consultants, specialists, suppliers, sub-contractors and

sub-contractors involved in potential schemes. • Advises and checks the design parameters for certain schemes. • Appoint a Temporary Works supervisor to supervise and monitor erection and

dismantling schemes. They would also be responsible for advising of issues or problems during construction and producing solutions.

• Manage the process responsible for ensuring implemented, consultation, design, coordination, procurement selection, methodology, seeking approval with interested Third Party stake holders.

• Approve Method statements and liaison with specialists in compilation of them. • Issue Permits to Load and proceed.

C) Temporary Works Design Engineers Professional engineers with certified qualifications and experience are appointed to review and approve designed schemes as required. They would issue design certificates indicating that the design is fit for purpose and in accordance with design guidelines and regulations. For complex third party interface arrangements they are necessary to ensure all parties are satisfied. D) Specialist suppliers of Formwork and Scaffolding In house design team. Major suppliers of Formwork and Scaffolding will have In-House design capabilities. These organizations will work closely with the Contractors at various stages from tender through to delivery. The Temporary works coordinator is responsible for managing and ensuring that they are following their design briefs to produce the optimum risk adverse solution.

It must be noted that their design will probably be required to be checked independently. Formwork suppliers do not offer on site management and erection services. Whilst scaffolding


company’s dependent on size can offer Design, Supply, erect and maintain type contracts. These interfaces have to be managed by the Temporary Works Coordinator and supervisor E) Permanent Works Design Engineers In the preparation of certain schemes it is imperative to engage the permanent works designer to ensure that all design interfaces have been taken into account and often the permanent is detailed to suit Formwork and Scaffolding systems. F) Temporary Works Supervisor Manages the site interface in conjunction with the Temporary Works coordinator, ensures Site erection team work in accordance with design. Works closely with team and engages with specialists such as Formwork company’s technical representatives and Temporary works Coordinator as required. The Supervisor must also be vigorous in checking the quality of components supplied purchase and dispose of if inadequate. They must also check query any anomalies with the design with the temporary works coordinator G) Formwork and Scaffolding erection Team. Site based personnel are responsible for following erecting the Formwork and Scaffolding schemes in accordance with the Method Statement and Design drawings and should have industry approved skill based qualifications and certifications.

6.7. Management of Temporary Works during the Construction Phase Once the schemes are designed and approved they will be installed in order to meet the project programme. The Main contractor would have the responsibility of coordinating all the proceeding activities and trades to ensure all interfaces are managed safely and in accordance with the specification. A) Categories of Falsework and Scaffolding The following categories are an example of guidelines that each company could classify differently depending on their procedures and experiences. Ultimately the main contractor must look at each requirement on a case by case basis. Minor Scheme’s Examples

• Falsework/ Floor Slabs up to 3m high • Formwork up to concrete pours 3m high • Simple propping and shoring up to 3m high

Major Scheme’s Examples

• Bridge Falsework • Slip forming Lift Shafts • Structural refurbishment support/ Façade retention • Formwork for Concrete pour height greater than 3m • Falsework for Concrete pour height greater than 3m • Marine works • Slabs greater than 300mm thick.


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B) Planning and design Phase The successful contractor securing the work will now focus in greater detail on the implementation of schemes envisaged at Tender. The Temporary works coordinator must review the prepared schedule and prepare Design brief to the contractor in a timely manner to meet the project schedule which would provide the following in detail.

• Permanent Works Drawings. • Soil/ Ground conditions. • Preferred methodology/sequencing. • Materials available. • Loading requirements. • Site Specific details, services, access issues, Third Party requirements.

C) Permits to Proceed Once the Erection team and the Temporary Works supervisor are satisfied that the scheme has been built correctly, it will be inspected and certified. The next stage would be for Temporary Works Coordinator to issue a Permit to proceed, this is a final inspection confirming what has been designed has been built and the concrete pour can commence. This process will be repeated as required until completion. The coordinator must also ensure design specification and temporary works procedures are satisfied prior to proceeding to the next stage. This could be typically ensuring 7- day concrete strength achieved and back propping of floor slabs to ensure load distribution (see claims example under section 5.1). For example, inadequate control of concrete placement such as the temperature and or excessive rate of vertical placement of concrete are factors influencing the development of lateral pressures that act on the forms could lead to excessive pressures which could lead to failure of the formwork. If temperature drops during construction operations, rate of concreting often has to be slowed down to prevent a build-up of lateral pressure overloading the formwork as is it is demonstrated below. Even when the basic formwork design is soundly conceived, small differences in assembly details may cause local weakness or overstress leading to form failure. This may be as simple as insufficient nailing, or failure to tighten the locking devices on metal shoring.


D) Routine Inspections during Construction Formwork and Scaffolding schemes can be in place for short durations such as a few days up to reasonable periods of time, sometimes years. During this time it is essential that routine inspections are conducted usually on as required, hourly/daily/weekly/monthly basis. These inspections must be conducted thoroughly by a competent person and recorded in a master register which can be audited by independent personnel. Failure to do this can lead to complacency and a system failure. E) Weather Events Prior to weather events and after weather events, the insured should carry out robust inspections to ensure the safety of the project team and also to the surrounding property and members of the public. Modifications or securing objects that could become flying debris need to be removed or secured. F) Permit to dismantle Once the permanent works have been completed and reached their design strength or alternative access is in place then the Temporary Works coordinator will issue a permit for the system to be taken down in accordance with the method statement and system procedures.


7. Conclusions: Most construction projects require the use of Formwork and Scaffolding to safely deliver the permanent works to the client’s specification. As projects become more sophisticated and are using ever developing new technologies of F&S with challenging programme constraints, there is an urgent need to ensure that the approach to temporary works schemes is well controlled and managed. F&S activities are usually not getting a lot of attention (on site) and in the UW process. In view of the frequency of “F&S-incidents”, underwriters should consider the F&S related risks when dealing with projects including:

• High structures using climbing formwork • Large span structures using cantilever and travelling formwork • Complexity and new technology of F&S • Advance loss of profit coverage of projects involving the above

Please make sure, policy wordings and definitions used are appropriately addressing Scaffolding and Formwork activities in order to avoid cumbersome loss adjustment procedures - so that we see fewer pictures such as this on the construction sites we insure!

Documents

IMIA Working Group Paper WGP 80 (13) IMIA Conference New ......strength and the low cost of bamboo. No machinery is needed to assemble the scaffold and it can be easily adjusted to