Structural retrofit of houses and buildings
So an older structure resists what today's code requires.
Photo: Josué Isaí Ramos Figueroa / Unsplash
Structural retrofit upgrades an existing building so it resists the loads and earthquake the NSR-10 requires. It starts with an assessment of the structure and ends with a signed intervention design (A.10.1.3). DDES does the assessment, the retrofit design and can supervise its construction.
- Code
- NSR-10, Chapter A.10
- Service
- Assessment and retrofit
- For
- Existing houses and buildings
What to have at hand
- Original drawings and calculations, if they exist.
- The approximate year of construction and any alterations made since.
- Photos of cracks, damp areas and elements with rust or spalled concrete.
- What you want to achieve: extend, change the use, or just make it safe.
How we solve it
- Inspection and survey of the structure.
- Tests where needed: concrete strength, reinforcement location, condition of the steel.
- Seismic assessment under the requirements of Chapter A.10.
- Retrofit design, with drawings and calculations for the permit and for the builder.
When does the NSR-10 require an assessment and retrofit?
Chapter A.10 applies to buildings built before the current code that are extended, modified or change use (A.10.1.3). Minor repairs that do not touch the seismic-resisting system do not require it, but a change of use does (A.10.1.3.2). An owner may also upgrade a building voluntarily (A.10.6.2 and A.10.9).
What level of safety is the goal?
A building intervened under Chapter A.10 must resist small earthquakes without damage, moderate ones without structural damage and strong ones without collapse (A.10.1.2).
DDES services for this case
Assessment and retrofit
Damage assessment, seismic vulnerability and retrofit design for existing buildings.
Structural design
Concrete, steel and masonry buildings designed to the NSR-10, from the first concept to the reinforcement details.
Technical supervision
Independent technical supervision under Law 1796 and Title I of the NSR-10, before every concrete pour.
Technical notes
Existing buildings: when the NSR-10 requires an assessment and a retrofit
Changes of use, extensions, structural alterations and earthquake damage: what chapter A.10 requires.
Seismic vulnerability study: what it is, when the NSR-10 requires it and what it includes
Chapter A.10 compares the existing structure with a new one and expresses it in two indices: overstress and flexibility.
When is a crack dangerous?
How to tell a cosmetic crack from one that needs an engineer: width, direction, where it appears and whether it grows.
Frequently asked questions
How do I know whether my house needs a retrofit?
The most common signs are growing cracks, exposed or rusted steel, columns or beams too small for what they carry, and houses built without an engineer. Only an assessment of the structure confirms it.
Is a retrofit the same as a repair?
No. A repair restores the capacity an element lost; a retrofit gives it more capacity than it had, so it meets the current code or carries new loads.
Can I keep living in the house during the retrofit?
It depends on the intervention. The design sets the order of the works and whether areas must be shored or vacated.
Other situations
- Adding a second floorBefore adding a floor you need to know whether the house can carry it.
- Crack assessmentNot every crack is serious, but every crack that grows needs to be studied.
- Warehouse designFrames, roof, floor slab and foundation, designed together.
- Retaining wallsFor basements, level changes and sloping lots.
- Tanks and poolsStructures that must not only stand but also not leak.
- Steel mezzanineMore usable floor area inside the same warehouse or store.
- Building permitWhich structural documents the curaduría asks for and who signs them.
Last updated:
Contact
Does your building need a retrofit?
Send us photos and tell us what you want to do with it. A DDES engineer tells you how to start.
Our team works in Spanish. You can write to us in English and we will get back to you.
Photo: Julia Taubitz / Unsplash