This is the fourth editorial that I've been asked to write for Structures and Buildings and, as always, it is a great honour and an opportunity for me to reflect on the latest developments in the field of Structural Engineering and the role of Academia in forming the new generations of professionals and pushing the boundaries of technical knowledge. I do that in a world that has been dramatically changed by the Covid-19 pandemic, where designers and contractors, lecturers and researchers alike have shown a great deal of resilience and have learned to work efficiently in new ways. Personally, this gives me hopes for a bright future and confirms my belief that our profession is only limited by our imagination.
Five papers appear in this issue of Structures and Buildings, demonstrating very clearly the breadth and richness of current research in the field. Ebead et al., (2020) present the results of an experimental campaign carried out on non-autoclaved aerated concrete with relatively high strength, ideal for a range of structural and non-structural applications. Abdel-Moniem et al., (2020) have developed an accurate finite element model to simulate the behaviour of reinforced concrete beams with dapped ends. This is indeed a very interesting structural problem, and one which I have direct experience of (e.g. Robinson et al., 2012). In my opinion, the availability of reliable numerical solutions is particularly desirable in this case, as it allows optimising the design of these structural elements beyond what can be done with the application of strut-and-tie models. Chen et al., (2020) have studied experimentally the ultimate bearing capacity and failure mode of a novel type of built-up column under axial compression, for which the authors have also produced a modified set of design equations. This type of research is very much needed to increase the confidence of designers and contractors in the use of cold-formed steel structures, and hopefully more papers will appear on this subject in future issues of Structures and Buildings. Shirkhani et al., (2020) present the results of an extensive numerical campaign aimed at optimising the seismic performance of steel frames equipped with T-shaped friction dampers. Proposed for the first time by Mualla and Belev (2002), these highly non-linear devices are able to dissipate large amounts of energy, provided that the slip load is exceeded. The latter parameter is therefore of key importance and needs to be carefully selected by the designer. This study shed some light on this interesting design problem, and the proposed approach can be extended to earthquake-resistant structures exploiting other mechanisms of energy dissipation (e.g. other mechanisms are discussed, in a rather informative way, by Palmeri (2015)). Last but not least, Catalán-Quiroz et al., (2020) have used shake-table tests on 1:2 scale-down models of traditional adobe dwellings in Mexico to quantify the seismic performance of a low-cost retrofitting technique consisting of a hexagonal mesh reinforcement and a thin layer of mortar on the walls. The results are very encouraging, as the proposed strengthening intervention increases both stiffness and strength of the model. Seismic retrofitting of existing structures, often with significant historical or artistical value, is indeed an area of research that deserves special attention. Luckily, as I had the opportunity to verify myself through a series of shake-table tests (Di Canio et al., 2008), relatively simple and inexpensive interventions can tremendously improve the dynamic behaviours of such structures.
Having now read all the papers included in this issue of the journal, I can only thank the authors for their excellent work. As usual, comments and discussions on these papers are welcome (please see the procedure detailed at the end of this editorial), as well as the submission of technical papers within the journal's remit.
Finally, if you have a professional or scientific interest in Wind Engineering, I hope to be able to safely welcome you to Loughborough for the 2021 Conference of the UK Wind Engineering Society. Extended versions of selected conference contributions may appear in a future themed issue of Structures and Buildings. Watch this space!
