CEN/TS 17440:2020 Assessment and retrofitting of existing structures

This article has been authored by Thomas P. Lang, Convenor TC 250/WG 2, Thomas Lang Consulting GmbH, Switzerland

CEN/TS 17440:2020 "Assessment and retrofitting of existing structures" is the first document prepared by Technical Committee CEN/TC 250 under Mandate M/515 to be made available to the CEN Member states. The document is available in English, French or German translations and can be purchased from National Standardization Organizations.

The 1st generation of Eurocodes comprise rules that are primarily intended for the design of new structures, although the principles of EN 1990 can also be applied for existing structures, with additional or amended provisions. CEN/TS 17440 is intended to supply the additional or amended provisions that can enable EN 1990 to be applied to the structural assessment of existing structures, including those that were not designed using Eurocodes. The provisions within CEN/TS 17440 also cover retrofitting, which is where existing structures are modified with the addition of new materials, for example to strengthen or extend them. CEN/TS 17440 is used in combination with the actions set out in EN 1991 Eurocode 1: Actions on structures, and provides complementary rules and guidance for how the actions should be applied in the assessment and retrofitting of existing structures.

The use of CEN/TS 17440 will enable the safety and serviceability of existing structures to be assessed using a consistent framework. It allows data from existing structures to be used to update the values for basic variables and update the structural models, thereby enabling a more realistic assessment of structural performance. It also includes some general principles for the assessment of structural resistance, highlighting the need to include the effects of deterioration and historic construction details. While a key purpose of the document is to assess the need for structural interventions, the scope of the document does not include any specific rules for undertaking or managing interventions on structures.

CEN/TS 17440 is a Technical Specification document, and it does not have the normative status of an EN document. It is intended to be used in combination with the 1st generation Eurocodes. The Eurocodes are currently being developed through Mandate M/515, which will result in a 2nd generation suite of Eurocodes that will include some new requirements relating to assessment and retrofitting. The conversion of CEN/TS 17440 into a new Eurocode part fully compatible with the revised 2nd generation Eurocode suite is an ongoing task within Mandate M/515, and the corresponding EN document is expected to be published by 2025.

Photos courtesy of Jon Shave, WSP

Photos courtesy of Jon Shave, WSP