Ordinance No. 302/2019 - Seismic Vulnerability Assessment

The aftermath of collapsed buildings in Concepción, Chile, after an earthquake that hit in 2010 | Dictuc

From the 15th of November, a seismic vulnerability assessment will be required for rehabilitation works

On the 12th of September, Ordinance No. 302/2019 was published, which defines the terms under which extension, alteration or reconstruction works are subject to the elaboration of a seismic vulnerability assessment report, as well as the situations in which the elaboration of a seismic reinforcement project is required.

In the works of extension, alteration or reconstruction it will be necessary to make a report of the evaluation of the seismic vulnerability - to identify its resilience to the seismic action defined in NP EN1998 -3:2017 - whenever one of the following conditions occurs: there are obvious signs of deterioration of the building structure; interventions alter the structural behavior of the building; the intervention area including demolitions and enlargements exceeds 25% of the gross building area of ​​the building; the construction (intervention) cost exceeds 25% of an equivalent new building's construction cost.

It is also mandatory to report on building seismic vulnerability in buildings of importance class III - seismic resistance is important given the consequences associated with its collapse (e.g, schools) - or importance class IV - Buildings whose integrity in the event of an earthquake is of vital importance to civil protection. (e.g, hospitals, fire stations, power stations) - according to NP EN 1998 -1:2010, whenever any of the above points is verified, established limits are reduced to 15%.

Please note that the design of seismic reinforcement under NP EN1998-3:2007 is mandatory when the seismic vulnerability report concludes that the building does not meet the safety requirements for 90% of the defined seismic action. " in that standard
- NP EN1998-3:2007 - Structures project for earthquake resistance. Part 3: Assessment and Rehabilitation.

LNEC is now competent to publish or approve constructive provisions or methods for expeditious analysis of seismic vulnerability in order to collaborate in the preparation of the seismic vulnerability assessment report.

In compliance with this ordinance LNEC has already made Seismic safety assessment guide for existing reinforced concrete buildings and the Methodology for the seismic safety assessment of existing buildings based on structural reliability analysis - Reinforced concrete buildings. Methodology for the assessment of seismic safety of existing masonry buildings is underway.

The introduction of new regulations, the requirement for seismic assessment of existing buildings and the possible need for the seismic reinforcement project is, in engineer Beatriz Melo’s from Neves & Ferrão opinion, a difficult task and a great challenge for all experts. The variety of the building in rehabilitation, both in terms of materials and in terms of constructive solutions is large, which will make the task difficult. However, in the case of reinforced concrete there is already a methodology developed by LNEC that will certainly help in the analysis but in the case of masonry work is still ongoing, which will make it very difficult to assess vulnerability for this type of building. LNEC states that the masonry methodology will be available before the 15th of November.

Be sure to consult all the documentation provided by LNEC , the new ordinance will take effect on the 15th of November.