This issue of Structures and Buildings consists of five technical papers, one commentary and one briefing. The research investigation covered herein concern reinforced concrete beams with a recess, building foundation and surrounding soil–structure interaction (SSI), shear strengthening of existing reinforced concrete beams with embedded bars, impact of rocking motion on the seismic performance of a linked column frame system, and damage detection of offshore platforms. Additionally, reflections on the recent earthquakes in Turkey-Syria are addressed, and new trends in teaching advanced structural analysis at University College London (UCL) are highlighted.
The first paper by Ali et al. (2023) presented an experimental and numerical investigation of a reinforced concrete beam having recesses in tension and compression sides tested under a four-point loading scheme. Based on the obtained results, the authors concluded that the most significant parameter influencing the investigated beams' structural behaviour was the recess depth from the viewpoint of stress concentration factor, cracking load and maximum crack width. Ultimately, recommendations and guidelines for the design of reinforced concrete beams with recesses are presented.
In the second paper by Panchanan et al. (2023), the authors investigated the seismic response of a representative asymmetric building equipped with semi-active dampers by accounting for the effect of soil-structure interaction. Two semi-active damping schemes–friction-type and two-step viscous–were considered, and their relative efficiencies were measured when compared with passive dampers. Comparative assessment between semi-active and passive dampers, with respective optimal damping parameters and placement, revealed the superiority of friction-type dampers over the others in reducing the response of the asymmetric building during seismic shaking.
The following paper (Caro et al., 2023) includes an overview of the deep embedment (DE) method – also referred to as the embedded through section method – a promising technique for concrete shear strengthening. Pull-out and beam test results were collected from the literature to identify gaps in the knowledge. The authors mentioned that the bond performance of deep embedment bars epoxy-bonded into concrete was not fully understood when pull-out tests were assessed. Moreover, when the beam tests were analysed, significant gaps in knowledge were found, particularly regarding the effect of concrete strength, loading type, shear span-to-effective depth ratio, size effect and deep embedment bar surface coating.
In the fourth paper, the investigation developed by Maroofi et al. (2023) concerned an assessment of rocking motion on the seismic performance of a linked column frame (LCF) system. A three-storey model based on the SAC building was designed based on storey drift demands and validated against experimental research in the literature. The changes in the linked column pattern from the incremental dynamic analysis indicated a 20% increase in the structural capacity of the LCF model.
The last technical paper by Beheshti Aval et al. (2023) looked at a novel approach to damage detection based on dispersion analysis and signal processing methods based on results obtained from a forced vibration test on the jacket-type offshore. Concerning a damage-engendered dispersion in the observed extracted frequencies, a novel damage index capable of accurate damage detection was thus developed. This work showed that the proposed index could determine the location and severity of damage with acceptable accuracy.
D'Ayala (2023) reflected on the Turkey-Syria earthquakes of 6 February 2023. The current toll stands at more than 52 000 deaths across Turkey and Syria, 1.5 million displaced and 265 000 buildings damaged or collapsed. The author mentioned that several concurrent causes contributed to the extent of the destruction. Firstly, the high accelerations with maximum peak ground acceleration (PGA) over 1.3 g corresponding to a value for the 475 years return period on rock was estimated as not greater than 0.6 g. Secondly, some building construction rules were ignored, resulting in the use of thin columns, slabs being cast onto columns without beams, soft storey failure of lower storeys, poor concrete mixes, poorly confined with few shear links, smooth bars, and insufficient longitudinal reinforcement, and for taller buildings, lack of shear walls in two directions.
Finally, Sebastian (2023) addressed an MSc module teaching advanced structural analysis at University College London (UCL). A key focus of this module was composite structures involving timber, since composite action reduces material consumption in alignment with the United Nations' Sustainable Development Goal 12.
The Editor would like to thank all the authors, reviewers and readers, and welcomes discussions on any of these papers.
