Background
SCOSS has become aware from a number of sources of concerns relating to the topic of robustness generally and disproportionate collapse specifically. This concern was articulated most recently at the workshop initiated and sponsored by SCOSS and held at IStructE on 30 October 2006.
It is clear that there is wide support for a guidance document, aimed at practising engineers, giving basic advice and solutions to common situations.
The aim of the guide would be to:
- Clarify the definitions, mechanisms and relevance of robustness and progressive collapse
- Summarise the requirements (and limitations) of the Building Regulations and the 'deemed to satisfy' material design codes (including incompatibilities and inconsistencies between codes).
- Illustrate, material by material, the specific issues and suggested solutions (if required)
- Illustrate solutions to hybrid construction and inter-material problems,
i.e. a practical explanation and guide to all structural designers and building control authorities which will enable consistency in the implementation and enforcement of design for robustness.
It is intended to be a working guide, not a thesis on the subject.
This note sets out a proposal for such a guide, and a suggested route for its production.
1 Scope
1.1 The scope has been derived from consideration of the concerns expressed though the SCOSS Workshop, the Verulam column in The Structural Engineer, and other contacts with industry. It is suggested as follows:
| 1 |
Introduction
- background
- need for guide
- aims
- limitations
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| 2 |
Terms and definitions
- clarification of common terms
1 Robustness
2 Progressive collapse
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| 3 |
Building Regulations - Part A3
1 Requirements
- general
- Class 1, 2A, 2B, 3
2 Issues associated with existing buildings
- classification
- multiple ownership
- hybrid construction
3 Standards of submission
- assumptions
- use of software
- single point of responsibility
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| 4 |
Design Codes and standards
1 Current codes and comparisons
- general (introductory assumptions)
- technical issues
- limitations
2 Eurocodes (EN 1991-1-7)
- assumptions
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| 5 |
Issues and solutions by material
1 Steel (hot and cold formed), including composite construction
2 Concrete (including precast work)
3 Masonry
4 Timber (including proprietary fabrications)
5 Hybrid constructions
6 Alterations and extensions |
| 6 |
Bibliography |
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Note: It is likely that the scope and content will evolve. The intent of chapters 1-4 is to describe (as needed) material specific issues. The problems associated with inter-material applications and hybrids would be covered in 5. Section 5.5 and 5.6 specifically will evolve with drafting and discussion.
1.2 The guide would take cognisance of other work in this area in order that it did not duplicate effort, including publications by NHBC, the material sectors, e.g. SCI and in The Structural Engineer. It is expected that guidance for class 3 structures will be limited to buildings which can be justified as needing no more than to comply with the criteria for class 2B.
1.3 The guide is not intended to be an academic treatise on this subject; it is intended for the practising engineer and building control authorities with the emphasis on safe design details, rather than the theoretical background.
Endnote
1 The initial idea for this guide came from SCI. SCOSS is grateful for their support in this respect.
2 Following discussions between SCOSS and IStructE, the latter has agreed in principle to the production of this guide. This is considered to be an important step forward.
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