Structural engineering in rehabilitation and strengthening works requires an effort for prior knowledge of the structure (geometric and mechanical), as well as knowledge of the codes and the analysis and design process of the era; and it also requires an engineering effort during civil works, far greater than is required for a new structure. The article explains three works developed in this area and which have notable singularities: The project to increase the bleachers at the Santiago Bernabeu Stadium, full of construction conditions and repetition, in a strictly designed structure and built at a difficult time to guarantee quality (completion in 2011). The new Teatro Principe Pio in a 100-year-old warehouse, protected heritage, where the challenge is to rehabilitate the structure to respectfully accommodate a new functionality (completion in 2020). The rehabilitation of a hotel in Ibiza, where the intense characterization work did not reveal the true state of the structure: the challenge of this work was to apply emergency engineering to try to make it possible to reuse it, without demolishing it (completion in 2019).
