Castle or House of Cards? - Strengthening the structural safety chain
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Castle or House of Cards? Strengthening the structural safety chain
Table of contents
1. Foreword 02
2. Structural safety (or lack of ) in the Netherlands 04
3. Failure of the structural safety chain 06
3.1 Micro level: human error and inadequacies 06
3.2 Meso level: shortcoming in collaboration and coordination of involved parties 08
3.3 Macro level: structure and culture of the industry 12
3.4 Summary 14
4. Action agenda for strengthening the structural safety chain 20
4.1 The players in the safety chain 20
4.2 The strategy 20
4.3 Eliminate the weak links 20
4.4 Strengthen the strong links 20
4.5 Maintain the safety chain
Bibliography 22
Colofon 24
Castle or House of Cards? | 01
1.
Foreword
Buildings collapsing: incidents or Building projects involve a large number of inspectorate, the building firm, and so on.
symptoms? different parties, and there is always a chain It is about actions – dos and don’ts – that
In recent years there has been a great deal of of tasks and responsibilities. There is are directly applicable to building projects.
publicity about collapses and near-collapses potential for something to go wrong at It also sets out some medium and long term
of buildings in the Netherlands. Politicians, every link in the chain. It is virtually actions aimed rather at solving inherent
the media and the building industry have impossible to identify a clear cause of a problems in structural safety. To implement
been questioning whether these were collapse or near-collapse: usually there will these actions, the Inspectorate for Housing,
simply incidents or whether there is be a series of mutually exacerbating causes. Spatial Planning and the Environment is
something inherently amiss in terms of Structural safety is a problem throughout involving educational establishments,
structural safety. This motivated the the safety chain! knowledge institutes and industry organisa-
Inspectorate for Housing, Spatial Planning tions in the Dutch building sector. The
and the Environment to initiate the The essay delivered important input for four Action Agenda was signed on 26 November
‘Ketenproject constructieve veiligheid’ expert meetings organised by the 2008 by representatives of a large number of
[Structural safety chain project], a project Inspectorate for Housing, Spatial Planning organisations in the sector, who thus
which aims to bring together as much and the Environment with experts from all committed themselves to implementing it.
knowledge as possible about the problems areas of the Dutch building industry in the
in this area and discuss them with the autumn of 2007. The result of these expert The publication you have before you
building industry. With this in mind, the meetings was subsequently turned into an contains the text of the essay ‘Kasteel of
Inspectorate for Housing, Spatial Planning action agenda entitled ‘Wég met de zwakke Kaartenhuis?’ and a summary of the actions
and the Environment published an essay schakels! - Actieagenda voor versterking van in ‘Wég met de zwakke schakels’. It provides
entitled ‘Kasteel of Kaartenhuis?’ [Castle or de constructieve veiligheidsketen’ [Away a clear picture of the structural safety
house of cards?] in the autumn of 2007. This with the weak links! Action agenda for problems in the Netherlands and the
‘Discussion paper on structural safety, or strengthening the structural safety chain] actions many of the players in the building
lack of’, as its subheading reads, contains a [2]. With this agenda, the Inspectorate for chain are taking to improve the situation.
summary of all the information known at Housing, Spatial Planning and the
the time about the main causes of the Environment is primarily addressing those
failures in the structural safety chain [1]. players in the safety chain who play a key
role in the structural safety of buildings: the
It is always extremely difficult to identify the client, the architect, the structural engineer,
‘culprits’ of a collapse or near-collapse. the municipal building and housing
02 | Castle or House of Cards?
Photograph: Signing the Action Agenda. Left: Dr. Ir. H. Paul, Inspector General.
Right: Mr. Drs. L.C. Brinkman Chairman of the Dutch Association of Building Companies detailed description of how structural safety can be guaranteed in
the various phases of the design and building process and what
Improvement initiatives roles the various partners in the chain can play regarding structural
The Inspectorate for Housing, Spatial Planning and the safety.
Environment is not the only organisation attempting to do
something about structural safety. Some initiatives have also been The Dutch construction and housing supervisory association,
taken by the building industry itself. Some of the most important Vereniging BWT Nederland, which represents a large number of
initiatives are described below. municipalities’ building and housing supervision departments, has
developed a set of standard protocols for checking building
Under the chairmanship of Prof. D.G. Mans, the research and applications and for municipal oversight on building sites [8, 9].
knowledge institute CUR initiated the ‘Leren van instortingen’ The theme of ‘structural safety’ is given a high priority in these
project [Learning from collapses] in 2004 [3, 4, 5, 6]. The aim of the protocols.
project is to initiate open, objective communication about
collapses and near-collapses and other unforeseen events during or BNA, the Royal Institute of Dutch Architects, and ONRI, the Dutch
after the construction of buildings. The project group is planning to Association of Consulting Engineers, have published a
analyse the technical and non-technical causes of these events with ‘Standaardtaakbeschrijving’ [standard task description]. This is an
a view to learning lessons for the future. The Inspectorate for automated online system for distributing, offering and contracting
Housing, Spatial Planning and the Environment is supporting this tasks in various disciplines involved in the design of buildings, in
project with knowledge and funding. their mutual context. In the latest update of this system (the ‘STB
This project was continued as a Platform on Structural Safety, 2009’), special attention was given to tasks around ensuring
established in 2008. An important activity is to set up and run a structural safety [10].
system to register and analyse incidents in building projects on a
basis of confidential signals. A succesfull pilot of this system has NEPROM, the Association of Dutch Project Development
been run till spring 2009. Companies, requires its members to abide by a special code of
conduct to safeguard structural safety. All related tasks and
Eight organisations, including the Inspectorate for Housing, Spatial responsibilities for each project must be set out in a responsibility
Planning and the Environment, the Concrete Association and table. In addition to obligations, the code of conduct also contains
structural engineers’ and builders’ organisations, have published a number of recommendations such as: ‘Ask for a second opinion
the joint ‘Compendium Aanpak Constructieve Veiligheid’ when working on critical and unusual structures’, or ‘Select a
[Compendium for a Structural Safety Strategy] [7]. This contains a builder on the basis of both price and quality’ [11].
Castle or House of Cards? | 03
4 | Castle or House of Cards?
2.
Structural safety (or lack
of) in the Netherlands
In recent years there have been several alarming reports of collapses The structural safety chain
or near-collapses of buildings in the Netherlands. There seems to be All the investigations reveal that it is never possible to identify one
a serious problem with structural safety. The newspapers - and not single cause for a disaster. There will always be a combination of
only the trade journals - are full of it. Disasters such as the collapse factors and circumstances that are an inherent part of the chain of
of the Maastricht balconies, the Tiel parking deck collapse and the players actively involved in the building process. All these players –
Bos en Lommerplein evacuation received nationwide attention. the client, the architect, the structural engineer, the municipality,
They are symbols of a structural unsafety as a social problem. The the building contractor, the site manager, the supervisors, the
image of the building sector, which has already been in the dock subcontractors and the suppliers who subcontract their own
since the construction fraud affair in the first half of this decade is structural engineers - influence the structural safety of a building
taking a severe beating. The lack of government oversight is often with their actions and interdependencies. In other words, there is a
denounced, with all the attendant consequences for the public’s distinct ‘structural safety chain’. An additional complicating factor is
perception of safety. What is going on? Politicians, the media and that there is no such thing as ‘the’ structural safety chain. The tasks
the building industry itself have been questioning whether these and roles that play an essential part in structural safety, like that of a
were simply incidents or whether there is something inherently coordinating or chief structural engineer, can be fulfilled by other
amiss with the structural safety of our buildings. players in each project, depending on the circumstances of the
project and the level of expertise those involved may happen to
The experts do not agree on the answer to this question. Some have [14].
regard them as nothing more than incidents, pointing out that the
vast majority of projects go off well and problems only arise in a very What is striking is that many causes come to light repeatedly in
small percentage of buildings. Others are convinced that there is a different cases. This may indicate that there could actually be
lot more going on than just a couple of incidental building faults. inherent problems with the structural safety of buildings. The initial
They believe that the disasters that make the papers are just the tip results of the pilot survey ‘Borging constructieve veiligheid in
of the iceberg. Some experts even consider the recent collapses and bouwprocessen’ [Ensuring structural safety in building processes]
near-collapses as symptoms of inherent flaws in the building [14] carried out on behalf of the Inspectorate for Housing, Spatial
process, a ticking time bomb beneath the building sector [12]. Planning and the Environment and the knowledge institute CUR
furthermore seem to confirm the existence of inherent flaws in the
Nobody knows exactly how big the problem is. There are no building process. This survey looked at five building projects in
statistics on collapses and their causes. Many cases are not reported which structural safety problems had not (yet) arisen. If these five
at all. It is also not known how many buildings have structural faults projects are representative of construction in the Netherlands, the
that are not yet visible but that could cause problems in the future. findings from the survey report give cause for concern1.
However, in recent years in-depth investigations of a number of
specific disasters have been undertaken by the Inspectorate for
Housing, Spatial Planning and the Environment, research organisa-
tions, the Dutch Safety Board, university professors, expertise firms
and specially convened committees of enquiry such as the de Boer
Committee, which the City of Amsterdam tasked with scrutinising 1
After finishing this pilot survey, 10 more projects have been investigated [25]. The
the Bos en Lommerplein situation [13]. results confirm the findings of the pilot.
Castle or House of Cards? | 053.
Failure of the structural
safety chain
In the ‘Learning from collapses’ project, the The client draws up a Schedule of a structural engineer and a technical
causes of collapses and near-collapses are Requirements (SoR). In an ideal world this consultant to design the technical services.
subdivided into three levels: SoR will be correct from the word go. But in The structural engineer designs and
reality SoRs are often subject to many calculates the load-bearing structures of the
1. micro level (human error and inadequa- changes throughout the design process, and building: he ensures that the building is
cies of people working on building sometimes even during the construction strong enough and will not collapse. The
projects); phase itself. There can be a great many good structural design is often a translation of the
2. meso level (shortcomings in cooperation - or not so good - reasons for this, but architect’s aesthetic ambitions, which can
and coordination between parties in the programme changes result in an increased sometimes conflict with the principles of
production chain); risk of design, detailing and execution structural safety. Architects often pay too
3. macro level (problems relating to the errors. We know from experience that little attention to this, preferring to leave it
structure and culture of the building design errors mainly occur when changes to the structural engineer to resolve.
sector). are made to the design under pressure of
time. Everybody makes mistakes, even in
Aspects such as regulation and education structural engineering firms. Mistakes
are included in the level last mentioned.. In fact structural safety is hardly ever paid might be made in the drawings, the
In this chapter we provide an overview of specific attention in SoRs. Clients implicitly calculations or the detail engineering
the major causes of the ‘failure of the assume that safety is adequately safeguar- (resulting in weak or unstable structures),
structural safety chain’ on each level. ded in laws and formal standards. They also joints might be designed with insufficient
assume that their consulting engineers and strength, or certain load events might be
contractors will comply with the regulations accidentally overlooked. The latter often
and standards, as required by the rules of appears to be the case when light-weight
3.1 Micro level: human error good workmanship [14]. In doing so they flat roofs collapse (see box). Sometimes
overlook the fact that there may be good insufficient attention is paid to the extreme
and inadequacies reasons why a building requires a higher wind loads near high buildings which can
level of safety than the statutory minimum, cause building facades to collapse.
Design faults perpetrated by people such as enabling other usage functions at a
Analysis of building faults reveals that most later stage.
faults arise in the preliminary and design
phases. The client commissions an architect to
produce the design. He also usually employs
06 | Castle or House of Cards?structural engineers have fewer and fewer opportunities to gain
Flat roofs are often found on buildings such as warehouses,
practical experience. On top of this there is a skills shortage which
factories and sports facilities. They are made of light-weight
means that many structural engineering firms cannot recruit
steel structures. In the past a lot less was known about these
enough people with an understanding of structures and the
structures and high safety margins would be allowed in the
necessary knowledge. University professors in the field are noticing
calculations. Nowadays we have a much better understanding
a general erosion of knowledge and command of applied mecha-
of materials and we are able to make such accurate calculations
nics, the mainstay of the structural engineering profession. These
that we can make each structure precisely as strong as it needs
factors all add up to the use of unqualified or inexperienced people
to be. This enables us to build structures that make optimum
for structural design [4, 14].
economic use of materials. But in unforeseen circumstances like
extreme rain or snowfalls, this can soon lead to problems [5]. If a
Automation also plays a role in this. The regulations are complex,
large volume of rain falls on a roof in a short space of time and
but structural engineers can use advanced calculation software that
the water cannot run off quickly enough, the roof can start to
can perform the structural calculations neatly in accordance with
sag in places. This causes more water to collect there, so the roof
the applicable standards. However, there is a serious risk that this
sags even more, and so on, until it gives way. Standardised
calculation software - essentially a ‘black box’ - will further diminish
calculation methods have been developed to determine the
people’s understanding of the subject [4, 14]. Sometimes computer
effect of water accumulation, but these are complicated and
programmes are even used as a substitute for thorough structural
time-consuming and are therefore often omitted.
knowledge. To put it briefly, improper use of advanced computer
programs can put structural safety at severe risk.
According to some experts, many structural engineers are insuffi-
ciently aware of the potential consequences of a structural failure [3, The construction firm, traditionally known as the ‘main contractor’,
4, 16]. They are calling for ‘robust’ designs and, where necessary, the is increasingly taking on the role of coordinator of suppliers and
installation of a second method of support to ensure that the forces subcontractors. Nowadays main contractors only perform a small
are dispersed elsewhere when a vital structural component gives part of the building work themselves and outsource the lion’s share
way. to specialist companies. In doing so they are forfeiting their
expertise and experience. It is also becoming increasingly difficult
In the Patio Sevilla complex in Maastricht, five balconies above one to find skilled construction personnel. Construction firms do not
another collapsed when the support on the bottom balcony gave have enough people with an understanding of structural
way. Had a second method of support been provided, this ‘progres- engineering.
sive failure’ would have been avoided.
Subcontractors are also plagued by a lack of skilled craftspeople in
In cases analysed in the CUR ‘Learning from Collapses’ project, the the labour market. Many companies are being forced to take on
lack of a clear ‘conceptual structural design’ is a commonly reported foreigners with whom it is difficult to communicate and who
problem [6]. A ‘conceptual design’ of this kind consists of a clear cannot read Dutch drawings.
description of how the structural designer envisages:
Suppliers of parts of the supporting structure such as prefab
• the transfer of loads to the subsoil; concrete components or steel structures are generally experts in
• the control of deformations and the dynamic behaviour of the their own fields but often have inadequate understanding of
structure; connecting structures supplied by other firms and the integrity of
• the stability of the structure; the structure as a whole. Some aspects can therefore fall between
• ensuring sufficient robustness of the structure (resilience, two stools, jeopardising structural safety.
warning behaviour when a problem occurs, possible second
method of support). Building faults
Analysis of collapses indicates that building faults perpetrated by
If the conceptual design is not clear, or is not properly documented the contractor or the supplier are rarely the main reason for the
– a frequent occurrence – there is a considerable risk of others collapses. One of the major exceptions to this was the Bos en
further down the building process drawing incorrect conclusions or Lommerplein incident, in which the reinforcements were not
making incorrect choices. produced in accordance with the drawings and the structural
engineers’ instructions [13]. This caused the concrete beams in the
Dwindling professional skill parking garage to crack, as a result of which the entire complex of
Many in the construction industry realise that the level of professio- shops, offices and apartments above the garage had to be
nal skill among structural engineers (but also among other players) evacuated.
is on the decline. They are becoming less and less involved in
management and supervision on the building site. The detailed
engineering of structures is being left to suppliers. As a result,
Castle or House of Cards? | 07Other building faults observed in such disasters include: 3.2 Meso level: shortcomings in
• p itch or camber on flat roofs not produced in accordance with the
collaboration and coordination of
drawing (collapses as a result of water accumulation). involved parties
• columns in office buildings not produced at the correct height,
causing the flat roofs to have an incorrect pitch or none at all Studies and analyses show that the main causes of collapses and
(ditto); near-collapses lie in the organisation of the building process.
• too few or wrongly positioned emergency drain outlets compared Various aspects of this are discussed in this section.
with the drawing (ditto);
• structures lighter than specified on the drawings; Incomplete, fragmented contracts
• use of lighter, weaker grade of steel than specified (Hoorn theatre Ever more knowledge is needed to design a good building. In
fly tower - although not the main cause of the collapse); addition to the architect, there are more and more specialist
• use of construction methods whose technical durability had been consulting engineers, each of whom is or can be responsible for
inadequately demonstrated during the reference period (e.g. part of the design. Together the architect and the consulting
adhesive bonding of facade elements); engineers need to ensure that they produce one single coherent
• welding and assembly faults causing joints to fail; design that meets the client’s needs. However, it is not uncommon
• use of certified products that do not meet the requirements of the for contracts to be awarded in an untransparent way, the division of
product certificate, or certified products not used as specified in tasks and responsibilities to be ambiguous and the importance of
the certificate. good design coordination to be badly underestimated. As a result,
important aspects can fall between two stools and it will not be
Faults in the usage phase clear who should be held accountable.
The causes of collapses can lie in the design or execution phase of
the building process, but also in its use phase. Many owners and
managers wrongly assume that a building that is built in accordance Ambiguous contract formulations cannot only be blamed on
with the building permit will be safe in all respects and under all clients. Structural engineers sometimes intentionally couch the
circumstances. Buildings are designed and calculated for a certain work descriptions in their bids in vague terms in an attempt to
use which will involve specific loads. Changes in use can cause an cover themselves against any risks associated with an incom-
unacceptable increase in the load without the owners understan- plete contract: they cannot be held accountable for work not
ding the implications. If an air-conditioning machine is installed on specified in the bid or contract. Specifying work in vague terms
a roof that has not been designed to support one, a heavy rain or also gives structural engineers the freedom to divide their
snowfall can cause the roof to collapse [17, 18]. Aging is another efforts over the various process phases of a project as they see
factor that is often paid too little attention. Steel can give way as a fit [14].
result of metal fatigue or rusting if it is not adequately maintained.
Wooden trusses can rot [18]. Periodic inspections during the usage
period are all too often overlooked. Clients are tending to earmark less and less of their budgets for the
structural aspects of projects. To save consultancy costs they may
Structures are designed for a specific reference period. The reference eliminate tasks or split contracts into smaller chunks. Often it is the
period for buildings is 50 years. This means that a building is crucial coordination tasks that fall by the wayside. Architects are
required to last for at least 50 years. Generally speaking, load-bea- increasingly being commissioned to produce no more than a
ring structures last much longer. But in some cases – particularly preliminary design and a final design, while another cheaper party
with joining techniques such as adhesive bonding – it is uncertain is contracted for the technical elaboration, the specification and the
whether the structure will still be reliable after the reference period. working drawings. The role of the architect is then, at best, reduced
Building owners are almost never aware of this and do not take any to ‘checking the shape’. The transfer of knowledge and information
action in this regard. about the original architectural and structural design starting points
is often poor. In very many cases the architect no longer supervises
One problem associated with management and maintenance is the the execution of the work. If the architect is involved in the
lack of good data such as drawings and other information docu- execution phase, his task is often limited to ‘aesthetic guidance’,
menting how the building was actually built (‘as built documents’). and nobody seems to know exactly what this involves.
The structural engineer is acknowledged by all the other parties as
the one specialist who can ensure that the structure is safe.
However, the structural engineer often finds that these same parties
are not giving him the leeway and opportunities to make their
expectations a reality. These days it is common practice for a
structural engineer to be selected partly on price. As a result of the
08 | Castle or House of Cards?price competition, he is forced to accept contracts at rock-bottom We have already noted that structural design engineers often fail to
prices. To ensure some degree of continuity, he is more or less document the conceptual design clearly. This results in poor - or
forced to spend as little time on a contract as possible. even no - transfer of the initial design concept and structural
preconditions to the builder, suppliers and structural engineers
The RVOI and DNR 2005 legal status regulations (or the ‘Standard who need to base their own parts of the work on it. Other shortco-
Task Description’ [10]) contain comprehensive task descriptions for mings identified include:
structural engineers. In order to save on consultancy costs, clients
are opting to eliminate some items from these task lists. So • i nadequate coordination of architectural and structural detailing
structural engineers are actually prevented from carrying out certain (architect and structural engineer);
relevant tasks [3, 4, 5, 6, 14]. As a rule, the structural engineer will • lack of coordination between architect, structural engineer and
still be commissioned to perform the detailed engineering of the contractor on the execution of structures;
concrete structures cast on site, but the detailed engineering of • uncoordinated use of multiple suppliers and subcontracted
items such as prefab concrete and steel structures will be left to the structural engineers without adequate control and monitoring of
suppliers. Furthermore, the structural engineer will often not be structural integrity;
instructed to check the detailing done by these other parties and • lack of a coordinating or chief structural engineer bearing
monitor the general integrity of the structure. Despite this, clients ultimate responsibility for the whole of the structural process;
implicitly expect structural engineers to do everything necessary to • poor management of drawings and calculations in the detailed
produce a safe structure. In other words, they expect more than they engineering and execution phases, with the result that not all
pay them to do. relevant parties are in possession of the latest versions of these
documents;
Some structural engineers do in fact do much more than they are • suppliers’ subcontracted structural engineers not familiar with
contracted to do, particularly if they consider it necessary to do so the context of their work, e.g. joints and interrelationships with
from the point of view of their own understanding of their task and other parts of the structure, and failing to raise the alarm when
their professional ethics. For example, it is quite rare these days for they receive too little information from the architect or the
a structural engineer to be contracted to oversee work on site on the original structural engineer;
client’s behalf. But he will sometimes go beyond his formal remit • lack of coordination between the design of the supporting
and will ask for information or visit the site at crucial times in the structure and the design of facades and their cladding,
execution process on his own initiative [14]. Likewise, the contrac- • the main structural engineer often will not see the detailed
tor’s foremen or project manager will sometimes contact the design of the facades because they form part of the architect’s
structural engineer for clarification. They will readily approach the package;
structural engineer with inspection or verification issues even if • poor management of design changes; lack of insight into the
they fall outside his official remit, particularly if they know him impact of changes on the action of forces in the designed
well. Thus structural safety seems to depend more on personal structures and insufficient focus on communicating changes to
experience, personal initiative and the parties’ understanding of all relevant parties;
their own tasks rather than structured, planned safeguards. • implementation of structural changes during the execution
without consulting the structural engineer and without adequate
Inadequate coordination and communication documentation;
The structural safety of a building involves a large number of • supervisors and builders are inadequately informed about the
people. Problems can occur because individual parties in the structural starting points and fail to ask for the underlying
structural safety chain make mistakes. But mistakes can also be information themselves;
made at transfer points and at the interfaces between the parties. • structural changes implemented on the basis of price, without
The latter can be partly overcome by good coordination and taking account of the integrity of the structure (e.g. by the
communication. A good coordination and communication contractor’s work planner);
structure can also ensure that individual errors are noticed in time • building in a way that does not comply with the building permit,
by others in the chain. Nonetheless, analyses of collapses and without documentation and communication with the municipa-
near-collapses reveal that coordination and communication are still lity/BWT;
not up to par. • failure to provide a set of the latest revised or as-built drawings.
Castle or House of Cards? | 09Process analysis reveals that the internal quality control and
From the work placement report of a TU Civil Engineering
assurance undertaken by designing parties is generally inadequate
student (1997):
and unprofessional. They tend to rely heavily on their own technical
‘Poor provision of information (particularly drawings) by the
knowledge and experience, which may not always be justified. Sadly
structural engineer meant a lot of time was wasted. As the
these are not the proverbial exceptions that prove the rule.
drawings nearly always contained mistakes, they always had to
be thoroughly checked. The most common errors were:
Construction supervision on behalf of the client is absent from an
• changes not implemented consistently: changes in elevations
increasing number of projects, because supervising the execution is
were not copied into the sections, floor plans or site plans;
regarded as the building contractor’s business. Building contrac-
• the shape of the reinforcement drawings did not correspond
tors, too, often do not want external supervisors on site. They argue
to the formwork drawings;
that supervision is not necessary because they work to their own
• reinforcements were drawn across expansion joints;.
quality and inspection plans. But these building contractors do not
• not all details of the concrete constructions were reinforced;
usually have their quality and inspection plans monitored by a
• reinforcements were placed too close together so they could
separate quality inspector. Quality assurance on the building site is
not be executed;
usually an additional task for the work foreman. In practice this can
• not all changes were identified with arrows .........’ [Source: 12]
lead to conflicts in the foreman’s priorities. Internal control and
supervision are at odds with what the foreman is primarily held to
If there is inadequate coordination between the many parties account for: time and money.
involved in the building process, building errors can occur that go
completely unnoticed. The increasing number of specialisms in
The concrete reinforcement in the Bos en Lommerplein project
construction only increases this risk. According to the Submission
was produced under great pressure of time. Three shifts worked
Requirements for Applications for Building Permits Decree (Biab), it
on the steel mesh reinforcements on different sites. A shift
is explicitly the client who is responsible for the integrity of
would sometimes be called away from its own work to assist at
information in the planning application. The same applies to the
another location where the cement mixers were waiting to cast.
structural integrity of the building. The Biab also states that if the
They could then return to their own work only to discover that
client is unable to coordinate the information himself, he must
the concrete had already been cast there even though the
instruct a suitably qualified person to do so. The risk therefore lies
reinforcement cage was not finished.
with the client, but the average client has no understanding of
structural safety or what steps he needs to take in this regard. He is
In its study report entitled ‘Gebroken Hart’ [Broken Heart] [13]
confident that everything will turn out right - after all, that is what
the de Boer Committee therefore stated that at crucial points in
he has engaged the consulting engineers for! But if the client fails to
the process there was evidence of inadequate quality control
make one of these consulting engineers specifically responsible for
and supervision on the part of the client, the building contractor
coordinating the information that needs to be submitted, there is a
and the municipality. Insiders say that this is no exception. A
reasonable chance that it will not be done properly by anyone.
salient detail: the building firm concerned is ISO 9001 certified.
Inadequate quality management
One method of preventing errors in the product and in the process In general, analyses and surveys reveal that insufficient attention is
is to exercise adequate quality management. In this context, much paid to risk assessment and risk management, both by the indivi-
is expected of certified internal quality management systems, and dual links in the construction chain and throughout the chain as a
great store is set by them. Most structural engineering and construc- whole. This is partly due to the tight deadlines and budgets the
tion firms have such systems in place these days. Many clients design and executing partners have to contend with. The fact that
believe that it is not necessary to bring in external quality control clients put short-term cost control above quality assurance and
and supervision2, since the companies involved are certified, after monitoring of integrity appears to be a widespread phenomenon.
all! In practice, however, it appears that there is little to be gained Nowadays designers and consulting engineers apparently have
from the pretensions of quality management systems. Certification virtually no time or budget to carry out thorough internal controls.
certainly does not seem to be a guarantee of quality [21], and quality There is too little external control and supervision on behalf of the
management systems are no substitute for technical inspections. client, and this is inadequately compensated for by internal control
What is more, a quality management system only relates to the and supervision by the building partners [3, 4, 13, 14].
activities of one company. Building projects involve a large number
of different firms working together, but there is virtually no Some clients and building partners appear to rely on the municipa-
coordination between their various quality management systems lity carrying out quality control. After all, the municipality assesses
[14]. planning applications against the Building Decree! So if a building
permit is granted, all must be well, they reason. But according to
the regulations it is the applicant, or the client, who is responsible
2
The aspect of liability also plays a role in this. More information can be found in
section 3.3. for ensuring that the design complies with the law. The applicant
10 | Castle or House of Cards?must demonstrate the structural integrity of the building. The • T oo often the focus is on bureaucratic aspects, with too much
permit holder (again, the client) is responsible for ensuring that the attention being paid to administrative tasks like meeting the
work is carried out in compliance with the building permit. The fixed deadlines in the issue of building permits, and too little to
supervisory department of the municipality (BWT) cannot and is not their content.
permitted to take over this responsibility. Nor can BWT play the role • Many municipalities have inadequately trained personnel with
of ‘coordinating structural engineer’ between all the different too little experience to be able to investigate innovative structu-
subcontracted structural engineers if the client fails to do so. res, for example. Many smaller municipalities have no structural
engineers on their staff at all. Check of structural safety is
In its report ‘Veiligheidsproblemen met gevelbekleding’ [Safety sometimes completely absent.
problems with facade cladding] [15] the Dutch Safety Board (OVV) • Some designers and builders seem to use the municipality’s
confirms that there is an inherent lack of supervision in the assessment as a substitute for their own quality control, and too
construction industry. The Safety Board is extremely explicit and many municipal officials allow this to happen.
consistent as far as the solution to this problem is concerned: under • The officials who issue the permits often fail to report to the
public law, the client bears ultimate responsibility, which requires municipal supervisors on the critical points which need to be
him - or someone on his behalf - to perform quality controls. The focused on during site inspections.
OVV is one of a growing group of organisations calling for the • Municipalities do not take adequate enforcement or other action
return of the ‘main structural engineer’ in the building process. In when essential calculations (such as for water accumulation) are
other words, the structural engineer who creates the structural not provided, when applicants fail to demonstrate structural
design should also be commissioned to monitor structural integrity integrity properly or when the provisions of the building permit
in the detailed engineering and execution phases. Others see the are not complied with. Measures such as rejecting the application
main structural engineer in the role of quality controller as a less or suspending building work are taken much too infrequently.
effective solution, or at best as just part of the solution. They are in • Little or no use is made of structured assessment and supervision
favour of engaging a completely independent controller/expert protocols. There is no statutory obligation for municipalities to
(‘Technical Inspection Service Firm’ – TIS) who could identify any adopt policy rules or protocols for building supervision (although
errors made by the main structural engineer also. since 1 April 2007 it has been compulsory to adopt an enforce-
ment policy and report on its implementation on an annual
Too little government control basis).
Central government is responsible for drafting the building • Supervision on building sites is often cursory or non-existent. Too
regulations such as the Housing Act and the Building Decree. little control is exercised to enable changes compared with the
Supervision of compliance is delegated to the municipalities (BWT). building permit to be identified and assessed in a consistent way.
The BWT is tasked with checking whether planning applications It should be pointed out, however, that changes compared with
comply with the applicable regulations. The Biab specifies what the building permit are very often not reported to the municipa-
information the applicant must submit to enable this control to be lity [16, 19, 20].
exercised properly and efficiently. It also specifies that the applicant • Building and housing supervision in the execution phase
cannot simply submit ‘loose’ data (drawings and calculations) but sometimes takes place for internal planning reasons and not on
must provide documentation that demonstrates the consistency of the basis of a risk assessment. Supervision is not, or is inadequa-
the information. There must be evidence of coordination in the tely, geared towards LMRAs or the building organisation’s own
submission, and that is the applicant’s responsibility. inspection schedule [14].
Control and supervision performed by municipalities in the context A shortcoming that can only partly be ascribed to the municipalities
of awarding permits and enforcement is based on the Housing Act. themselves is the fact that in many cases permit holders fail to
It responds to the government’s general interest in ensuring sound notify commencement of the work and provide proper information
building, and complements rather than substitutes the quality about the execution of essential parts.
assurance provided by market parties and/or the supervision carried
out on behalf of the client. Municipalities do not have the manpo-
wer or the resources to check everything; checking can only be done
on a random basis. Taking this into consideration, studies by the
Inspectorate for Housing, Spatial Planning and the Environment,
the de Boer Committee (Bos en Lommer) and others have highligh-
ted a number of shortcomings in municipal building and housing
supervision which seem to be more than incidental. The most
important of these are summarised in point form below.
• T here is often too little manpower available for adequate
inspections, enforcement and supervision.
Castle or House of Cards? | 11risk of recipients of information not understanding exactly what the
A determining factor for the effectiveness of municipal
information is about. Nonetheless, analyses of collapses and
supervision is the availability of manpower and the authority
near-collapses reveal that it is precisely coordination and communi-
with which BWT can act. In the ‘Ensuring structural safety in
cation that is lacking in the building process [3, 4, 6, 14, 22]:
building processes’ [14] pilot project, several parties - structural
engineers, contractors, project managers - reported that they do
• There is often no clear division of tasks;
not consider BWT to have any authority. The reasons for this
• The exchange of information between building partners is often
include the following:
‘depressingly bad’;
• There is a ‘gap’ between the admissibility test and the actual
• Planned management and control tasks are not carried out (for
inspection of drawings and calculations which can be
example, quality and assessment plans are drawn up but in the
submitted up to three weeks before the execution date;
hectic and dynamic atmosphere of the building works they are
• BWT’s inspections lag behind the dynamics of the building
not always adhered to [14]);
process, so that observations are often retrospective (timing);
• Interfaces between disciplines are neglected.
• BWT inspectors are often unable to be present on the
building site at the right times and for a sufficient length of
Focus on price and time
time because of their working hours, both in terms of number
A second aspect relating to the structure and culture of the
and start and end times;
construction sector is the overwhelming focus on time and price.
• BWT inspections show insufficient understanding of
The organisational culture is one of building and commissioning
structural design (………….);
fast, with quality and care seemingly taking a back seat. With the
• It is known that inspectors will not always be able to take
pressure from competition, consultants, building firms, sub-con-
matters further, even if they want to; the officials do not
tractors and suppliers are often forced to work for low prices and to
always have a high enough level of authority to be able to
tight deadlines, with the result that some tasks simply fall by the
intervene (mandate).
wayside. As an illustration: an average structural engineering
contract currently accounts for something in the region of 1.5% of
the total building cost. In the past the percentage was considerably
3.3 Macro level: structure and culture of the higher. But the amount of work needed to ensure a sound and
structurally safe design has not changed significantly. This has
industry obviously put quality under pressure.
When collapses or near-collapses happen, there is almost always
evidence of a combination of human error and shortcomings These days it is quite common to see projects being subjected to
(micro level) and a lack of cooperation, coordination and commu- irresponsibly short deadlines. Time is money. Designers no longer
nication between parties (meso level). If one were to weigh up all have time to read, understand and check everything [14, 25]. Under
the factors, one would be able to identify certain patterns that pressure from deadlines, penalty clauses and planning, contractors
insiders are also familiar with from other sources. These patterns have a low acceptance threshold for ad-hoc solutions to discrepan-
relate to the structure and culture of the building sector. In this cies in the details [14].
section we discuss some of these aspects that are relevant in relation
to the structural safety of our buildings. Complicated legislation
In general, the legislation is regarded as adequate in itself. However,
Increasing specialisation many designers consider it to be too complex. In addition, it has
The volume of knowledge of materials, technologies and building been found that many designers and consultants only have limited
methods has increased enormously over the years [6, 22]. This knowledge of the Building Decree. The standards can also often be
inevitably brings with it ever more in-depth specialisation. There is extremely complicated. What is more, the volume of legislation has
so much knowledge that a technical expert can never master his or increased significantly over the years. On the one hand this is due to
her field of expertise fully. Furthermore, buildings and building the fact that new technological knowledge is coming on stream in
designs are becoming increasingly complex. The limited space in leaps and bounds, but on the other hand it can be ascribed to the
the Netherlands makes it essential to combine functions and make fact that we increasingly insist on taking design and building right
multiple use of space. The present generation of CAD programs to the brink of what is possible (see box). The methods to be
enables us to design complicated spatial structures, so this is followed are laid down in detailed standards. The adaptation of
happening. These developments mean that more and more standards to European regulations has also made the matter more
specialists are needed to be able to build these buildings. This only complex. And the end is not yet in sight.
increases the coordination task and makes clearer communication
ever more important. Not only must building partners ensure
effective and full exchange of information between them, but the
information being exchanged needs to be able to be interpreted by
the recipients. The more specialisations there are, the greater the
12 | Castle or House of Cards?between clients and building contractors. Typical of these general
In 2007 a series of problems with the structural safety of
terms and conditions is the far-reaching restriction of contractor
balconies arose in several building complexes. Having learned
liability compared with the Civil Code. Among other things, these
lessons from the fatal accident at Patio Sevilla in Maastricht in
liability restrictions mean that there is no particular sense of
2003, local authorities closed off some balconies pending
urgency with regard to ensuring adequate (independent) quality
further examination confirming whether they were safe or
control. In other countries where liability for construction partners
whether structural measures would be needed. Following these
is far less restricted, there is a much greater awareness of liability
events, Cobouw interviewed Prof. D.G. Mans, chair of the CUR
and stronger quality management. Insurance companies play a
Learning from Collapses Committee. Prof. Mans underlined
significantly smaller role in our country.
once again that the problem was to a large extent caused by
failures in the organisation of the construction process.
According to the UAV’89, a client who has the construction work
Structural engineers only perform fleeting checks, and
supervised on its behalf can be held liable (or partly liable) for
manufacturers of prefab balcony floors do not always get full
so-called ‘non-hidden faults’ which manifest themselves after
information from contractors. The fact that appearance seems
delivery of the building. There is jurisprudence on this, particularly
to be the main criterion for balconies these days also exacerba-
from arbitration. This shows that if the client has the management
tes the problem. Sturdy brackets are giving way to internal
and supervision of the work performed on its behalf, the contractor
structures built into prefab floors. Mans: ‘New balcony designs
is not liable for execution faults which the manager or supervisor
are often borderline. Designers tend to minimise supports and
could or should have seen if they were acting with due care. The
dimensions. This makes these balconies susceptible to
client is therefore entirely responsible for the loss or damage. This is
tolerances and structural faults.’ [23]
without doubt one of the reasons why clients are increasingly
deciding not to have construction work supervised.
Because of the complexity of the standards, construction has, as it
were, become a matter of following a recipe from a cookery book, at Leading construction lawyers are in fact calling for an urgent review
the expense of the insight and intuition that characterises the true of the situation. They consider the fact that a client is liable for
art of cooking. mistakes made by a building contractor to be difficult to sell in
To put it bluntly, training courses are turning out people who have current times and to be in contravention of the principle of
learnt to do tricks. When they are confronted with something that reasonableness and fairness. The party that makes the mistake in
differs from the norm, they do not know how to apply the rules the first place should have to bear the lion’s share of the loss. If the
because they have no insight and do not know the background to client appoints another party to manage the work, it is reasonable
the rules [22]. Experienced structural engineers are convinced that and fair for it to bear some of the liability, but to a lesser extent. This
professional skills can only be transferred to a younger generation is also the tenor of articles in the Civil Code relating to these kinds
of structural engineers by supervising them as they work. They are of cases. Fortunately, the Arbitration Board has issued opinions in
concerned at young people’s training levels and the possibilities (or favour of holding the party who makes the mistake responsible for
impossibilities) of giving graduate structural engineers additional, it [24].
on-the-job training on projects. In the current market, budgets
simply do not extend to this [14]. Throughout the construction Such liability problems can be an issue for a ‘main structural
industry, from architects and structural engineers to contractors and engineer’ or ‘coordinating structural engineer’ whose task it is to
municipal supervisors, there is no culture of ongoing on-the-job monitor structural integrity. This person checks the drawings and
training, as is the case in the legal profession, for example. calculations produced by the structural engineers subcontracted by
suppliers. It is impossible for this coordinating structural engineer
Although there is little intrinsically wrong with the legislation, to check everything, as there is usually no time and budget for this.
some of the standards are questionable. Following a heavy snowfall It is therefore usually done in the form of a spot check. If the
in November 2005, for example, it was found that the actual load structural engineer is working on behalf of the client, the latter may
created by the melting snow was significantly higher in places than be liable for mistakes in subcontracted structural engineers’
provided for by the load calculations in the standards. documents which were not spot-checked by the coordinating
structural engineer. The client can and will then hold the coordina-
Liability ting structural engineer liable. This process can result in clients
A final aspect which we need to touch on is the national system of choosing not to appoint a main structural engineer or a coordina-
liability in construction. The liability of different participants in the ting structural engineer, thus clearly placing liability for mistakes
process is generally regulated in standard general terms and with the party who makes them. This despite the fact that the
conditions. These are declared applicable in the contracts between appointment of a coordinating structural engineer - by whichever
client and contractor. Examples of general terms and conditions are party - is generally regarded as one of the essential measures for
the DNR 2005 for contracts between clients and design/consulting ensuring the structural safety of our buildings.
disciplines (formerly the SR and RVOI) and the UAV’89 [Uniform
Administrative Conditions] which regulates the legal relationship
Castle or House of Cards? | 13Determining liability for a collapsed building can result in years of 3.4 Summary
legal to-ing and fro-ing between the parties involved. The sequence
of events following the collapse of the unfinished theatre fly tower The contents of this chapter, ‘The failure of the structural safety
in Hoorn is an illustration of this (see box). A clear example of the chain’, are summarised in the diagram on the next page.
‘failure of the structural safety chain’ and yet more proof that
structural safety is a matter that involves many parties. The links in the ‘structural safety chain’ are illustrated in a highly
simplified way in the centre of the diagram. It also shows which
party (or function) in each link in the chain should take the lead in
During the night of 10 April 2001, the steel structure of the fly
terms of the design and execution of supporting structures. What
tower being built in Hoorn’s new theatre collapsed. Analyses
can go wrong within the links (‘micro level’) is shown in the top part
brought to light mistakes in the structural design and detail
of the diagram. In the centre we can see the problems that arise
engineering. There were at least four structural problems, each
between the links (‘meso level’). Many of the problems at this level
one of which should have resulted in the structure being
are the result of shortcomings in cooperation, coordination and
rejected [4]. Experts differ as to which of two critical phenomena
communication between the various parties in the building
ultimately caused the collapse: insufficient strength in the joints
process. The bottom part of the diagram shows a number of causes of
or instability of the upper member of a lattice girder which is
problems relating to the structure and culture of the construction
subjected to compressive bending loads. Two other shortco-
industry (‘macro level’).
mings - the use of a lower-strength grade of steel than had been
specified and the fact that part of the bracing was missing - were
probably not direct causes of the collapse. The following
circumstances play a role, however [4]:
• changes were being made;
• the structural engineer did not manage the changes properly
and did not understand the implications in terms of the full
action of the forces;
• the third-party detailing was not submitted for inspection
either to the structural engineer or to the municipality;
• there was insufficient coordination and communication
between the various disciplines;
• the municipality’s inspections and enforcement action were
inadequate;
• although warning signs in the structure in the form of large
deformations were observed by the inspector and reported to
the structural engineer, their relevance was not assessed.
Conclusion: Mistakes were made throughout the entire safety
chain. The outcome is that a definitive decision on the issue of
liability is still outstanding today (August 2007) ….
14 | Castle or House of Cards?You can also read
