SIST EN 1991-1-6:2026/oprA1:2026

SIST EN 1991-1-6:2026/oprA1:2026 is the Slovenian draft amendment that mirrors CEN EN 1991-1-6:2026/prA1:2026. It updates Eurocode 1 - Actions on structures - Part 1-6: Actions during execution, the part used for determining actions that matter while a structure is being built. The document is aimed at designers and execution teams working on buildings, civil engineering works, and related auxiliary structures, elements and equipment.

What does SIST EN 1991-1-6:2026/oprA1:2026 specify?

SIST EN 1991-1-6:2026/oprA1:2026 is a draft amendment to the Eurocode part on actions during execution. It revises the underlying standard’s guidance for the execution stage, including buildings, bridges, civil engineering works and geotechnical structures, and it updates references and explanatory notes in selected clauses.

The underlying document says that actions during execution include both:

• actions that arise only from execution activities, such as personnel, hand tools, auxiliary structures, equipment and elements used during execution
• actions that also exist in the finished structure, such as self-weight and wind, when they act differently or with different values during execution

The document is organized as modifications to the whole text and to the Introduction, Scope, Normative References, Design situations, and Additional considerations on actions during execution. The foreword also states that the draft is submitted for CEN enquiry and that it will modify EN 1991-1-6:2026 if approved.

What are the key requirements of SIST EN 1991-1-6:2026/oprA1:2026?

SIST EN 1991-1-6:2026/oprA1:2026 keeps the core Eurocode approach: execution-stage actions are assessed using the Eurocodes, with the general assumptions of EN 1990. In practice, this means the designer must treat the construction phase as a real design situation, not just a temporary afterthought.

The document applies the limit state principle and the partial factor method, unless a different rule is explicitly given. That matters because actions, combinations and verification checks are handled in the same structured way as other Eurocode design situations.

Main points the amendment highlights

• Actions during execution cover both construction-only actions and permanent actions that behave differently during execution. This matters when load paths change during erection, lifting or temporary support removal.
• Auxiliary structures, elements and equipment used during execution are included when they are designed to the Eurocodes rather than to other European Standards. This affects temporary works, scaffolding-like systems and other execution equipment.
• Buildings and bridges during execution are covered to supplement EN 1990. For combination rules during execution, the document points to EN 1990-1 and, in one note, to EN 1990-2.
• Transient design situations must be checked with interaction between the permanent structure and any auxiliary structures, elements or equipment. Practically, teams need coordinated checks across temporary and permanent works.
• Planning, documentation, communication, control and supervision are assumed to be adequate during execution. This means the design basis must be matched by site control and coordination between the parties involved.
• Instantaneous application of actions can be significant when temporary supports are removed or when bridge spans are lifted or slid into place. That is important for deciding whether short-lived but high load effects govern the design.
• The amendment updates the wind-related reference for resonance wind action effects to EN 1991-1-4:2026, Annex F, Annex G and Annex H.
• It also aligns seismic wording with EN 1998. For execution-stage design, this keeps the relationship between Eurocode 1 and seismic provisions clear.

What terms does SIST EN 1991-1-6:2026/oprA1:2026 define?

The document uses several key terms in its scope and assumptions.

• Actions during execution - loads and influences that affect the structure while it is being built.
• Construction actions - actions that arise only because of execution activities, such as personnel, hand tools and temporary equipment.
• Auxiliary structures - temporary or supporting structures used during execution and considered in the design checks where relevant.
• Transient design situations - design conditions that apply for a limited time, such as the construction phase.
• Limit state principle - the design approach that checks whether a structure meets safety and serviceability conditions.
• Partial factor method - the Eurocode method that applies factors to actions and resistances in verification.
• National Annexes - national choices that set values related to regulatory safety matters at country level.

Who uses SIST EN 1991-1-6:2026/oprA1:2026?

SIST EN 1991-1-6:2026/oprA1:2026 is used by structural engineers, geotechnical engineers and bridge designers who need to verify the structure during erection or other execution stages. It is also relevant to designers of auxiliary structures and temporary works when those items are designed to the Eurocodes.

Contractors, execution planners, site supervisors, quality managers and project coordinators use it to organize load checks, temporary support arrangements, lifting stages, documentation and supervision. It also helps teams that coordinate design, fabrication, transport and execution across several specialties.

What changed in SIST EN 1991-1-6:2026/oprA1:2026 from the previous edition?

This draft amendment is prepared to modify EN 1991-1-6:2026 and, if approved, will supersede it. The stated changes are:

• replacement of references from EN 1990:2023 to EN 1990-1:2023+A1:2026
• replacement of EN 1990 with EN 1990-1 in most places
• replacement of references to EN 1991-1-1:2025, EN 1992-1-1:2023 and EN 1998-2:2025 with their +prA1:2026 versions
• addition of a note pointing to EN 1990-2
• clarification of the seismic wording in the Introduction
• clarification in Design situations that removing temporary supports or moving full spans into place can create instantaneous load effects
• update of the wind resonance reference to EN 1991-1-4:2026, Annex F, Annex G and Annex H
• update of the note in clause 7.3 to EN 1990-1:2023+A1:2026, 7.1.3

Which standards are used with SIST EN 1991-1-6:2026/oprA1:2026?

The amendment names these connected standards and parts:

• EN 1990-1:2023+A1:2026 - the basis of structural and geotechnical design for new structures, used for general design rules and combinations
• EN 1990-2 - cited for combination rules for execution where additional or amended provisions may be needed
• EN 1991-1-4:2026, Annex F, Annex G and Annex H - used for resonance wind action effects
• EN 1998 (all parts) - used for seismic design or assessment provisions that complement EN 1991
• EN 1991-1-1:2025+prA1:2026 - updated cross-reference within the Eurocode actions series
• EN 1992-1-1:2023+prA1:2026 - updated cross-reference for concrete design
• EN 1998-2:2025+prA1:2026 - updated cross-reference within the seismic Eurocode series

What does the SIST EN 1991-1-6:2026/oprA1:2026 document contain?

SIST EN 1991-1-6:2026/oprA1:2026 mainly contains amendment instructions rather than full design text. The contents list six modification groups: changes throughout the whole document, to the Introduction, to Scope, to Normative References, to Design situations, and to Additional considerations on actions during execution.

The foreword identifies the draft as a CEN/TC 250 document under enquiry and explains that it is part of the second generation of Eurocodes. The body of the amendment then gives targeted wording changes that update references, clarify execution-phase load effects, and align the document with related Eurocode parts.