Over the past 10 years, an ever-increasing and by now significant part of low-to-middle income population in some South American countries, namely Colombia, Peru and Dominican Republic among others, has moved to new reinforced concrete (RC) buildings whose structural skeleton is composed of walls. These vertical members not only support the weight of the building but also resist to the horizontal loads imposed by earthquakes, which are a serious threat in these medium to high seismicity regions. The new building typology adopted in Colombia presents distinct and unseen features from most RC wall construction worldwide, which raise concern within the scientific, engineering, and construction communities in Colombia, as well as in society overall, regarding the possible underperformance of this structural system under seismic loading. In order to reduce material costs, which are critical with respect to labour costs, very thin walls with only one layer of non-ductile steel reinforcement bars are being used, together with very thin slabs. Some building walls have a simple rectangular cross-section geometry, but most have very irregular non-rectangular geometric shapes, such as U-shapes, to accommodate lift shafts or staircases and to respond to architectonical configuration constraints. Their seismic behaviour is quite distinct and it can be reasoned qualitatively that U-shaped thin walls are more prone to instability and non-ductile failures than their rectangular counterparts. Unfortunately, the desirable quantification is still missing since no experimental tests on U-shaped thin walls with one rebar layer were performed to date. The present project covers this unacceptable gap by performing large-scale tests of U-shaped walls in Colombian and Swiss laboratories, which will allow to characterize the behaviour of these structural members under horizontal loads along different angles. Potential structural weaknesses that should be taken into account by engineers, either in the design of new buildings or in the assessment and strengthening of existing ones, will be identified. The experimental results will also enable the development and calibration of reliable computer simulation models of entire buildings, which will be used to derive trustworthy fragility and vulnerability curves. The latter, together with extensive data collection for a state-of-the-art exposure model, will finally produce estimates of the seismic risk of this building class in the biggest Colombian cities. This project builds on the partners’ expertise on experimental tests, U-shaped walls, rectangular single-layered thin walls, and seismic risk assessment. The conclusions will be made available to local and national authorities and used to update the national construction code. The extensive research network of participant Colombian and Mexican universities, alongside with targeted seminars and journal publications, will guarantee an adequate dissemination of the project outcomes, while simultaneously strengthening a 5-year long partnership and paving the road for future cooperation.
