What is NA to BS EN 1991-1-7 - accidental actions on structures about?
NA to BS EN 1991-1-7 is a National Annex to safety standards that discuss accidental actions on structures. NA to BS EN 1991-1-7 aims to maintain the integrity for efficient and timely implementation of risk mitigation measures.
NA to BS EN 1991-1-7 gives recommendations and guidance for safeguarding buildings and other civil engineering works against identifiable and unidentifiable accidental actions.
NA to BS EN 1991-1-7 gives:
- The UK decisions for the Nationally Determined Parameters described in the following subclauses of BS EN 1991‑1‑7:2006+A1:2014:
— 2 (2) — 4.3.2 (3) — 4.6.1 (3)
— 3.1 (2) — 4.4 (1) — 4.6.2 (1)
— 3.2 (1) — 4.5 (1) — 4.6.2 (2)
— 3.3 (2) — 4.5.1.2 (1) — 4.6.2 (3)
— 3.4 (1) — 4.5.1.4 (1) — 4.6.2 (4)
— 3.4 (2) — 4.5.1.4 (2) — 4.6.3 (1)
— 4.1 (1) — 4.5.1.4 (3) — 4.6.3 (3)
— 4.3.1 (1) — 4.5.1.4 (4) — 4.6.3 (4)
— 4.3.1 (2) — 4.5.1.4 (5) — 4.6.3 (5)
— 4.3.1 (3) — 4.5.1.5 (1) — 5.3 (1)P
— 4.3.2 (1) — 4.5.2 (1) — A.4 (1)
— 4.3.2 (2) — 4.5.2 (4)
- The UK decisions on the status of BS EN 1991‑1‑7:2006+A1:2014 informative annexes; and
- References to non-contradictory complementary information.
Who is NA to BS EN 1991-1-7 - accidental actions on structures for?
NA to BS EN 1991-1-7 on accidental actions on structures is useful for:
- Civil engineers
- Construction engineers
- Site managers
- Architects
- Site inspectors
- Regulatory bodies
- Regulatory authorities
Why should you use NA to BS EN 1991-1-7 - accidental actions on structures?
If accidental actions on structures can be discovered in the event of accidental design scenarios, verifying the key element is one of the design methods that may be used. This approach reduces the chances of a local breakdown and later gradual collapse.
NA to BS EN 1991-1-7 provides a description of principles and application rules for the design of structural systems subjected to accidental actions including impact forces actions due to internal explosion and local failure.
According to NA to BS EN 1991-1-7, two groups of strategies are proposed in order to assess accidental design situations – those based on identifying accidental actions and those based on limiting the extent of localized failure.
NA to BS EN 1991-1-7 is proposed to design the structure to have sufficient minimum robustness, to prevent or reduce the effect of the accidental action, or to directly design a structural system to sustain the action.
The strategies are based on limiting the extent of the localized failure, either by increasing redundancy of structure or designing key elements to sustain national accidental actions and applying some prescriptive rules like ductility or integrity. NA to BS EN 1991-1-7 guidelines help with efficient structure design so that risks are mitigated and users have uninterrupted access to the structures they use.
Second Generation of EN Eurocode Standards
The second generation of EN Eurocode standards is expected to be published between 2023 and 2026. These documents are being published as soon as they are available, to enable users to prepare for the transition from the first generation to second generation of Eurocodes. As set out in the National foreword of the BS EN second generation Eurocodes, UK adoptions of the first generation of Eurocodes will be withdrawn by BSI on 30 March 2028. That means there is a period of coexistence between 2023 and 2028 during which both first and second generation Eurocodes are available.
Until 30 March 2028, the first generation documents should be considered as the applicable standards for buildings and civil engineering works constructed in the UK unless otherwise specified by the relevant authority or in the specification for a particular project. While the use of provisions in second generation Eurocodes in conjunction with first generation Eurocodes is not precluded, it should be undertaken with care and should only be done when users are satisfied that it will not result in a lower level of reliability than the minimum level set in the first generation Eurocodes and associated UK National Annexes.
