SIST EN 1998-2:2006/A2:2012

SIST EN 1998-2:2006/A2:2012 is the Slovenian adoption of the European amendment EN 1998-2:2005/A2:2011 for Eurocode 8, Part 2 on bridges. It gives the seismic design rules for earthquake-resistant bridges and updates the annex rule for the minimum isolator temperature used in seismic isolation design.

What does SIST EN 1998-2:2006/A2:2012 specify?

SIST EN 1998-2:2006/A2:2012 specifies the particular Performance Requirements, Compliance Criteria and Application Rules for the design of earthquake-resistant bridges within Eurocode 8. It is the bridge-specific part of the seismic design framework, so users apply it together with the general Eurocode provisions and other relevant parts.

The standard mainly covers bridges where horizontal earthquake actions are resisted by bending in the piers or at the abutments, including bridges with vertical or nearly vertical pier systems supporting the deck. It also applies to cable-stayed and arched bridges, but its provisions are not stated as fully covering those cases.

It excludes suspension bridges, timber and masonry bridges, moveable bridges and floating bridges. For low seismicity, simplified design criteria may be established.

What are the key requirements of SIST EN 1998-2:2006/A2:2012?

SIST EN 1998-2:2006/A2:2012 organizes bridge seismic design around a set of core topics: basic requirements and compliance criteria, seismic action, analysis, strength verification and detailing. In practice, that means a bridge project must address the earthquake input, the structural response, the strength checks and the detailing needed to achieve the intended behavior.

• The standard is used within the framework of EN 1998-1:2004 and the rest of Eurocode 8. Practically, bridge design is not done in isolation - the designer combines the bridge rules with the general seismic design basis.
• The bridge rules are aimed at structures where piers or abutments provide the main horizontal resistance. This matters because the load path and deformation checks are different from other bridge forms.
• Cable-stayed and arched bridges are included, but the text warns that the provisions do not fully cover them. In practice, these bridge types may need additional judgment and related design checks.
• Suspension, timber and masonry, moveable and floating bridges are outside the scope. That tells the user to choose a different design basis for those structures.
• In low seismicity, simplified design criteria may be established. This is relevant when the seismic demand is limited and the project is using a simplified route allowed by the standard.
• The standard includes a special section on seismic isolation. For isolated bridges, the designer must treat the isolators as key structural components, not as secondary devices.
• Annex G gives rules for capacity design effects. This supports design of the intended hierarchy of strengths, so less desirable failure modes are kept out of the critical path.
• Annex J governs seismic isolator unit properties, and Amendment A2 updates the minimum isolator temperature rule so it reflects the climatic conditions of the bridge location. For practice, that means the design temperature for isolators is tied to local climate data and the National Annex may provide the method.

What terms does SIST EN 1998-2:2006/A2:2012 define?

• Performance Requirements - the earthquake-resistance objectives the bridge design must satisfy.
• Compliance Criteria - the checks used to show that the design meets those requirements.
• Application Rules - the practical rules used to apply the design provisions in real projects.
• Seismic isolation - a protection method that reduces earthquake effects on bridges by using isolator devices.
• Seismic isolator units - the isolator devices whose design properties and variation must be considered.
• Capacity design effects - the effects used in design to control where yielding or critical demand is allowed to occur.
• National Annex - the national document that can specify how the country applies the standard, including the method for minimum isolator temperature.

Who uses SIST EN 1998-2:2006/A2:2012?

SIST EN 1998-2:2006/A2:2012 is used by bridge and structural engineers, earthquake design specialists, checking authorities, and infrastructure owners involved in bridge construction and assessment. It is relevant when designing new bridges, checking seismic resistance of piers, abutments and decks, or specifying seismic isolation for bridge projects.

Quality managers, reviewers and procurement teams may also use it to confirm that a bridge design basis includes the right seismic bridge provisions and the correct annexes for isolators and capacity design.

What changed in SIST EN 1998-2:2006/A2:2012 from the previous edition?

SIST EN 1998-2:2006/A2:2012 is an amendment to EN 1998-2:2005. It replaces J.1(2) in Annex J so that the minimum isolator temperature for the seismic design situation corresponds to the climatic conditions of the bridge location.

The amendment also adds a note pointing users to the National Annex for the national method of determining that temperature and to related temperature definitions from EN 1991-1-5 and EN 1990.

Which standards are used with SIST EN 1998-2:2006/A2:2012?

• EN 1998-1:2004 - defines the overall scope of Eurocode 8 and points to additional parts of the series.
• EN 1990:2002 and EN 1990:2002/A1:2005, Annex A2 - provide the combination factor for thermal actions in seismic design situations.
• EN 1991-1-5:2003 and EN 1991-1-5:2003/AC:2009 - provide the temperature terms used in the Annex J note, including annual average shade air temperature and bridge temperature components.
• Other relevant Eurocodes and other parts of EN 1998 - used together with this bridge part for complete seismic design.

What does the SIST EN 1998-2:2006/A2:2012 document contain?

The document contains a foreword and one technical modification to Annex J. The amendment text replaces J.1(2) and adds a note explaining how the minimum isolator temperature can be set from local climatic conditions, with reference to national application rules.

The note also points to the temperature data and combination rules used in the calculation method. For a reader, that means the key content is the updated seismic-isolation temperature rule rather than a broad rewrite of the bridge code.