Civil Engineering Reference
In-Depth Information
Figure 6.3 The London Millennium Bridge
of the then unquantified synchronous lateral excitation but the
designers of the Ronan Point building were held liable for the
collapse because they failed to consider that the panels should
be tied together.
From the provisions, a schedule of calculations needs to be
drawn up and implemented.
The main validation questions are: Do the provisions ade-
quately address the issues? Are they relevant to the context?
Four types of issue can be identified:
1.
Codified - where provisions are available in a code of
practice.
2.
Not codified but quantified - at least one method of deal-
ing with the issue has been published but it is not available
in a code of practice.
3.
Identified but not quantified - some people know about the
issue but there are no published provisions for it.
4.
Not previously identified.
Clearly there can be no justification for omitting a codified
issue. Type 2 issues soon get incorporated into a code - this is
how codes develop as new issues are identified. Designers may
not be held negligent for omitting a Type 3 issue (the London
6.5.1.2 Process validation
To address the design issues 'provisions' are used. Normally
the provisions come from a national or international code of
practice. Where suitable provisions are not available in the
national code, the designer has to look to other sources, e.g.
codes from other countries, design guidance, books and pub-
lished papers. Sometimes there is no guidance and the provi-
sions have to be developed ad hoc. This was the situation for
tie action in the design of large panel buildings in the 1960s.
In some cases, the need for tie action was not recognised (i.e.
the requirements were deficient). In other cases, the need for
tie action may have been recognised but was not adequately
provided for.
