The behavior of steel frame buildings under progressive collapse conditions depends on a combination of several parameters, including the interplay between different collapse resistance mechanisms that are mobilized in different structural components. Previous studies have shown that the extent to which these mechanisms may contribute to progressive collapse resistance depends on the ability of the beam-column connections to undergo large inelastic deformations prior to reaching their deformation capacity limits. For this reason, and due to the important role of their flexural strength and tying capacity in the development of essential collapse resistance mechanisms, the response of beam-column connections is one of the most important features of progressive collapse performance. Based on the knowledge gained through previous studies on the mechanics of this problem, the role of these connections are critically reviewed in this paper by examining the results of several experimental studies that have been conducted during the past decade. The factors that may adversely affect progressive collapse resistance–such as the failure modes of certain connection types–are evaluated, and novel approaches to limiting these factors, which are currently under development, are reviewed. The assessment of these parameters leads to useful conclusions of practical significance while highlighting the aspects of these problems that need further study and understanding.

Real-time monitoring systems are crucial for the comprehensive management of operations and processes, as well as for assessing the impacts of coastal infrastructures on the marine environment. These systems not only support environmental protection and data-driven decision-making but also enable the early detection of adverse events and the issuance of timely warnings for prompt responses. Although water quality is a critical parameter in this monitoring framework, there are currently limited permanent systems in place dedicated to maintaining these objectives. Even fewer systems leverage their data for research purposes, leading to a gap in the literature regarding effective processing approaches for real-time water quality data. In this context, this study presents a real-time water quality monitoring system integrated into a broader in-field laboratory installed at a coastal area off the coast of Ayia Napa, Cyprus, as well as an initial measured data set of different qualitative quantities. It proposes a holistic approach for post-processing real-time seawater quality data, employing both time and frequency domain analyses, alongside filtering techniques. The study discusses the advantages of each method and emphasizes the importance of their combined use. Utilizing data collected from a three-month operational period, the study assesses the current state of marine seawater quality and examines both temporal and cyclic variations in various seawater quality parameters. The findings reveal that the examined seawater parameters are within reasonable values, indicating that the construction and operation of a nearby marina and the necessary infrastructures (e.g., breakwater) did not affect the seawater quality in the area. Additionally, the study identifies pronounced daily cyclic responses in different seawater quality parameters, including temperature, density, pH, dissolved oxygen, and turbidity. Finally, notable correlations are observed between temperature and dissolved oxygen, temperature and conductivity, oxidation–reduction potential (ORP) and salinity, ORP and dissolved oxygen, and ORP and TDS.

The Imperial College Robustness Assessment Framework is a methodology—based upon application of the alternate load path concept—for quantitatively comparing the performance of different structural arrangements to a threat-independent triggering event (removal of a single column) with the potential to induce a progressive collapse of the structure. Initially, it depended upon the numerical analysis of a representative beam. More recently, the application of more basic structural mechanics has been found to yield almost identical results at a fraction of the cost, thereby making use of the approach by nonspecialists far simpler. Although this study was mainly restricted to the coverage of steel and composite frame structures, the principles apply to any construction type. Important aspects of these simplifications, including demonstrating both the accuracy and rigor of the resulting approach and the ease with which many variants of a proposed scheme may be compared in such a way that the precise influence of key variables may readily be assessed, are collected together herein.

This study presents three-dimensional finite element analyses of two marine structures subjected to lateral loading to approximate environmental forces (e.g., wind, waves, currents, earthquakes). The first structure is a marine jetty supported by twenty-four piles, representative of an existing structure in Cyprus, while the second is a simplified four-pile marine structure. Soil–pile interaction is modelled using nonlinear p-y, τ-z, and q-z springs that are distributed along the piles, while steel plasticity is also considered. This study examines the relationship between failure modes, deformation modes, and plastic hinge locations with soil behaviour and soil reaction forces. It also aims at investigating the behaviour of the above structures in lateral loading and quantifying the consequences of unrealistic assumptions such as soil and steel linearity or tension-resistant q-z springs. The results indicate that such assumptions can lead to the wrong prediction of failure modes, plastic hinges, and critical elements while emphasising the crucial role of soil nonlinearity and axial pile–soil behaviour on the structural response. It is demonstrated that the dominant nonlinear sources relevant to this study, whether soil nonlinearity, plastic hinge formation, or a combination of the two, are primarily influenced by the axial capacity of soil–pile foundation systems, particularly their tensile component.

The behaviour of steel frame buildings under progressive collapse conditions depends on a combination of several parameters including the interplay between different collapse resistance mechanisms mobilized in different structural components. Previous studies have shown that the extent to which these mechanisms may contribute to progressive collapse resistance depends on the ability of the beam-column connections to undergo large inelastic deformations prior to reaching their deformation capacity limits. For this reason, and due to the important role of their flexural strength and tying capacity in the development of essential collapse resistance mechanisms, the response of beam-column connections is one of the most important features of progressive collapse performance. Based on the knowledge gained through previous studies on the mechanics of the problem, the role of the connections is critically reviewed by examining the results of several experimental studies conducted during the past decade. The factors that may adversely affect progressive collapse resistance – such as failure modes of certain connection types – are evaluated, and novel approaches of limiting these factors which are currently under development are reviewed. The assessment of these parameters leads to useful conclusions of practical significance, while highlighting the aspects of the problem that need further study and understanding.

This paper explores methods of simulating the behaviour of building structures under progressive collapse conditions through alternative models of different levels of structural idealization. Such alternative simulation models have been applied in many previous studies of the problem, but there is insufficient information regarding the degree of reliability and appropriate representation of the actual structural behaviour as the model is simplified by reducing the level of structural idealization. To investigate the problem, the study adopts the alternative load path method through the well-established concept of notional column removal. The study focuses on the interaction of the directly affected structural members with their neighboring structural components. The results demonstrate the significant influence of this parameter on the overall structural response under progressive collapse conditions. Most importantly, it is demonstrated that this parameter depends on many factors and is difficult to quantify without explicitly analyzing the behaviour of the surrounding structure. As a conclusion, a local failure that can potentially lead to progressive collapse should be analyzed in the context of the global behaviour of the structure. Alternatively, effective methods for simulating the boundary conditions of individual structural members should be studied and developed to enable the application of reduced analysis models.