The call, up front. When back-to-back quakes drop buildings in a dense city, the failure isn’t the engineering: base isolation (setting a building on shock-absorbing bearings) and carbon-fibre wrapping (wrapping columns so they don’t shatter) both work. It’s throughput: how many buildings actually get done, and how fast. Both proven methods are too slow and too costly for the millions of non-ductile concrete and soft-story buildings (concrete that cracks and fails instead of bending, and buildings with a weak, open ground floor) that need them, so most never get them. Tens of thousands already sit under a legal duty to retrofit (to upgrade an existing building), in a queue nobody can clear at current cost. The gap is a retrofit fast and cheap enough to apply across whole neighbourhoods.
The gap
The methods aren’t the question: the throughput is. Base isolation works but is too expensive for mass use; forcing existing private homes up to current building codes is politically dead. No method is both fast and cheap enough for whole neighbourhoods.
Don't compete with base isolation on performance. Win the queue. A standardized, fast, low-cost retrofit, paid for by the city or the insurer, serves the dense pool of non-ductile buildings the premium methods can't reach.
Source: LADBS (Los Angeles building department); San Francisco ESIP; Concrete Coalition / EERI; Anagnos et al. 2014 (counts are buildings)
Counts are buildings under existing retrofit mandates or hazard inventories (official lists of at-risk buildings). Los Angeles non-ductile concrete (~1,500) is already counted inside the California statewide figure (~17,000), not added on top. FEMA: 'existing buildings are the single biggest contributor to seismic risk in the US,' with ~75% of older concrete failing standard evaluations though only a small share at high collapse risk, which is exactly why triage (sorting buildings by risk so the most dangerous get fixed first) and cheap mass retrofit matter.
Source: GAPTIQ engine: challenge decomposition
- 2013San Francisco mandates soft-story retrofits (~5,000 buildings)
- 2015Los Angeles Ordinance 183893: ~13,500 soft-story + ~1,500 concrete buildings
- 2017Italy's Sismabonus offers up to 85% tax credit for seismic retrofit
- 2024New Zealand extends earthquake-prone-building deadlines by four years: mandates slipping
Source: SF ESIP; LADBS; Italy Sismabonus; NZ Building Amendment Act 2024
The move
The market is whole neighbourhoods of non-ductile buildings that will never afford base isolation, and that already carry a legal duty to retrofit. Whoever delivers a standardized, fast, low-cost method, payable by the city or the insurer, serves a population today’s premium methods price out and a queue today’s methods can’t clear. The mandates are written; the throughput is the gap.
Source: Older Concrete Buildings: Understanding the Seismic Risk (FEMA P-2018), FEMA. Triggered by Venezuela’s back-to-back Caracas earthquakes. Surfaced by the GAPTIQ engine.
