final-report-of-the-advisory-committee-on-falsework-bragg-report - Flipbook - Page 7
Introducsion
The interim report of the committee was published in
April 1974. In publishing our preliminary findings
and indicating the lines on which we were working
our aims were to prepare all those involved in falsework design and construction for our final report,
and to stimulate them to provide additional evidence
on which we could work. We were much heartened
by the response. Various authorities and firms have
already taken action on our early recommendations,
and we received most valuable and constructive views
from contractors, engineers, architects, agents and
representatives of employees. We take account of all
this additional information in our final report, and in
particular have expanded on parts of our interim
report where it was apparent that a more complete
exposition was desirable.
The problem
The constraints set by the need to temporarily support
construction works in exactly the right position are
evere. Each project is unique. There are few guides
to good practice and there is often considerable doubt
about the actual loads which will occur. Much reliance
must be placed on the few skilled men who have
experience of falsework design. The need to dismantle
the equipment afterwards sets fresh problems. The
contractor has his own materials and equipment
which must be used where possible.
Working conditions on an exposed site are far from
ideal. Good planning is needed to ensure that skilled
men, materials and equipment are available at the
right time. New hazards arise from weather, unexpected site conditions, and from the non-availability
of critical resources of men or materials, which make
modification and improvisation necessary.
Another complication is that so many different
pecialist organisations are involved. The design of the
permanent works may be done by one group of
consulting engineers and the design of the falsework
by another specialist group. A preliminary design
may be needed for estimating purposes and then the
final design may have to be done in a great _hurry
when the contract has been awarded. Equipment may
be supplied and erected by specialist sub-contractors
who have not previously worked together. This diersity introduces difficulties of communication and
a confusion of responsibilities which is worsened by
complicated or imprecise contractual arrangements.
Finally the work force itself is often transient. Men
ign up to work on one site but may not be prepared
to stay with the contractor and move to another
part of the country for his next job. This exacerbate
the problems of providing training and maintaining
the discipline on which safety depends.
Over all these activities hangs the need for economy
and speed. The contractor is committed to completing
the structure for a fixed cost by a certain date. The
designer must provide a safety margin, yet he cannot
afford to waste material. Safe construction practice
must be followed in detail, faults must be corrected,
yet the next critical step must not be delayed. Good
planning, preparation and inspection are needed to
ensure that corners are not cut.
In spite of all these difficulties most falseworks are
designed, constructed and dismantled without accident. The aim of the Committee was to find out why
accidents occurred and to recommend how they might
be avoided.
Operation of the Committee
The committee decided at its first meeting, on 5 April
1973, to study evidence from known collapses. It
read reports in technical journals and government
publications; received evidence from those involved in
the collapses at Loddon Viaduct (1972) and Birling
Road (1971); and from other firms and organisations,
and much help was received from HM Inspectors of
Factories who were able to abstract the relevant technical points from a number of reports covering a wide
range of conditions and causes of failure.
Simultaneously we solicited information from overseas. The Overseas Division of the Department of
Employment helped us to get reports from USA,
Canada, Australia, South Africa, Germany and
France. Two of our members visited North America,
and another went to Bavaria to obtain first-hand
information on the collapse at Kempten.
Part 1 of the report provides details of some of the
collapses we studied. These included major disasters,
but we must emphasise that we also obtained evidence
on smaller jobs; indeed far more accidents occur on
building sites than on major works of engineering
construction.
Our studies showed that failures arise from many
different causes. Each one has two elements: the
technical cause which led to collapse; and the procedural errors which allowed the faults to occur and
to go undetected and uncorrected. In Part 2 of the
report we discuss the commonest technical faults.
In hardly any case did we find that failure was. the
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