In recent times, with an increased focus towards sustainable and innovative structural materials, cross-laminated timber (CLT) has been shown to be an excellent product in terms of both structural properties and environmental impact. In Europe, CLT is primarily manufactured with strength class C24 timber or a combination of C24 with small proportions of class C16 timber in the internal layers and as such, there is significant research related to the structural properties and construction using C24 CLT. However, it is important to establish properties for CLT manufactured from lower-grade timber as the supply of C24 grade timber is readily available in central Europe but many other regions are limited to lower grades. This paper is focused on examining the behaviour of wall-to-floor CLT connections in assemblies using C16 grade timber and aims to provide evidence to ensure existing Eurocode design guidelines are valid for lower-grade material. Commercially available angle brackets have been studied for three different fastener lengths by subjecting them to compression and shear loads. The characteristic values obtained from the experimental results are compared to the values obtained from the analytical models of current design codes. These results shall inform the behaviour of CLT panels manufactured from lower-grade timber in combination with typical connectors and thus facilitate the optimal connection design of CLT connections in structural mass timber systems constructed using lower-grade CLT.

Modern steel erection relies on two main connection methods, welding and bolting, which can be expensive field activities and have remained unchanged for nearly a century. To achieve savings in both weight and cost, increased construction effectiveness and higher steel reuse, a novel type of toothed steel connections with the use of precise, advanced manufacturing methods in waterjet or laser cutting has been established that is based on an interlocking approach to connect steel components that have exactly cut ends. This paper presents testing and finite element analysis (FEA) studies of three unique flange plate geometries of the toothed steel connections failing in tension. Tensile tests were carried out on six samples of the toothed flange connections for each of the three geometries and the digital image correlation (DIC) method was utilized to attain axial displacement. The observed key test results, including load—displacement responses, yield loads, failure loads and modes, were fully presented. Strain contours of the connection geometries with the use of the DIC technique at early stage loading and near ultimate failure were also presented. The experimental program was accompanied with a numerical modeling program, in which finite element models were first created in Abaqus structural analysis software and compared against the test results. Based on the tests and numerical data, the performance and the capacity of the three unique flange connections were assessed. The FEA results agreed very well with the test results, indicating that the numerical simulations can accurately predict yield, ultimate load capacities and failure modes of the toothed connections. The numerical models characterized thoroughly the predicted stress distributions within the connections. For capacity-based design, the second flange connection (CON2) geometry could be adopted in beam tensile zones due to its better overall performance.

Urban regeneration investments, particularly those involving multi-million-euro allocations, require diverse evaluation methodologies to comprehensively assess their impacts. This paper aims to evaluate the effects of a substantial urban regeneration investment in Limerick, a county in west of Ireland, characterized by significant deprivation. The case study examined is the Limerick opera house, a major mixed-use development comprising office space, a public library, hotel accommodation, and leisure facilities. This project offers an exemplary context for analysing a complex urban regeneration initiative characterised by multiple, interrelated objective. Utilizing a hybrid, downscaled multi regional input output (MRIO) analysis alongside impact analysis, this study examines the economic, environmental, and social impacts of the project. The results indicate that the project generated 1676.43 jobs during the construction phase and 2400 jobs in the long-term phase. However, the employment opportunities created did not substantially benefit deprived areas, primarily due to a mismatch between the skill sets required for the jobs and those available within the local population. This study highlights the necessity for supplementary training and upskilling initiatives to effectively target these communities. Future research may focus on refining the model from an environmental perspective, incorporating more robust methodologies for carbon pricing and cost-benefit analysis.

Harvested wood products (HWPs) are significant in sustainable construction because they provide renewable, low-carbon material alternatives. Through climate change mitigation, renewable resource utilisation, and carbon sequestration, HWPs help reduce the environmental footprints of buildings. Since the construction industry is a major contributor to greenhouse gas emissions, exploring sustainable building materials like HWPs is imperative. This paper aims to address the gap in addressing the full lifecycle assessment of HWPs in construction by conducting a comprehensive review that incorporates economic, environmental, social, and spatial dimensions. The literature reveals that current assessments remain fragmented, often overlooking the broader timber lifecycle and its interconnected sustainability implications. To address this, the review suggests a more integrated lifecycle approach, explicitly including preharvest land use changes and post-use carbon and economic dynamics, which are often missing in traditional evaluations. By combining evidence from various fields, this study builds a structured understanding of how HWPs serve as long-term climate mitigation tools, not only as renewable material options but also as active parts of circular bioeconomy strategies. This systemised review evaluates HWPs across all lifecycle stages, preharvest (as a preproduction land use decision), production, and post-use, highlighting the need for a more integrated sustainability framework. Key findings underscore the importance of applying a lifecycle approach to better understand how early land-use decisions, market incentives, and end-of-life practices interact to shape carbon outcomes and economic returns. Ultimately, this review advances a more coherent and actionable understanding of HWPs as drivers of circular and climate-resilient construction.

Advanced manufacturing is providing fabrication technologies (e.g., laser and plasma) with a rapidly expanding set of cutting possibilities especially when coupled with robotic arms, which is already spawning new structural steel connection prototypes. Adoption of such connections will necessitate (1) the ability to consistently describe and represent them, and (2) a broad industrial consensus as to what those terms should be. Unlike traditional fabrication activities of bolt holes, perpendicular cuts, and welds, the new fabrication options may necessitate describing non-circular openings, non- perpendicular cuts, canted and tapered teeth, and significantly more connection points than are presently employed. Furthermore, such new terms may necessitate training of erectors and field inspectors, as well as fabricators. This paper uses the new introduced Interconnected Steel Connection as a sample visual data dictionary.

Various approaches have been proposed for bridge structural health monitoring. One of the earliest approaches proposed was tracking a bridge’s natural frequency over time to look for abnormal shifts in frequency that might indicate a change in stiffness. However, bridge frequencies change naturally as the structure’s temperature changes. Data models can be used to overcome this problem by predicting normal changes to a structure’s natural frequency and comparing it to the historical normal behaviour of the bridge and, therefore, identifying abnormal behaviour. Most of the proposed data modelling work has been from long-span bridges where you generally have large datasets to work with. A more limited body of research has been conducted where there is a sparse amount of data, but even this has only been demonstrated on single bridges. Therefore, the novelty of this work is that it expands on previous work using sparse instrumentation across a network of bridges. The data collected from four in-operation bridges were used to validate data models and test the capabilities of the data models across a range of bridge types/sizes. The MID approach was found to be able to detect an average frequency shift of 0.021 Hz across all of the data models. The significance of this demonstration across different bridge types is the practical utility of these data models to be used across entire bridge networks, enabling accurate and informed decision making in bridge maintenance and management.

Measuring bridge displacements using Unmanned Aerial Systems (UAS) is an emerging field offering the advantage of a remote non-contact approach for measuring bridge displacements. Unfortunately, UAS measurements contain the motion of the UAS which needs to be compensated for to get true bridge displacements. So far, UAS bridge displacement studies have compensated the unwanted motion of the UAS from measurements by tracking a minimum of 4 stationary points required as the minimal solution to calculate a Projective homography between two UAS camera views. While this has been shown to be effective, a reduction in the minimal solution would make these methods more robust to factors such as loss of stabilising points or temporary occlusion to an object entering the scene. In this paper, by combining recent advances to the Perspective-3-Point problem that make camera pose calculation from 3 points reliable and calculating a Euclidean homography instead of a Projective homography, we show in a laboratory experiment that structural displacements can successfully be made to submillimetre accuracy using only 3 points instead of the traditional 4 points. This is done with only visual information from video feed without the need for any additional sensors.

Green Public Procurement (GPP) is an increasingly important environmental policy being incorporated with national action plans (NAP) across the European Union (EU). The aim of this paper is to look at related literature in the construction industry with a goal of identifying any gaps in literature. In addition, the review defines different facilitator and barriers to implementing GPP in the construction field. The paper employs a relatively unique approach using a theoretical framework to explore a wider set of variables within the GPP field. All papers from year 2000 onwards in English were considered for the review. The review finds a lack of emphasis on systems modelling within the reviewed paper set and a need for more diverse economic evaluation metrics that incorporate social and environmental costs. Furthermore, the paper discusses broad range of subjects varying from behaviour to tendering procedure, highlighting potential avenues of future research.

Structural Health Monitoring (SHM) has mainly been undertaken on larger bridges and on a case-by-case basis. This is due to a range of factors, such as the high installation costs and the effort required to install and commission the monitoring systems. One way in which SHM systems can become more feasible for widespread adoption at a network level is to reduce the number and cost of sensors used. However, this comes with a trade-off as low-cost sensors will typically have a worse signal-to-noise ratio and the reduced number of sensors requires careful placement to maximise the amount of information acquired. One of the simplest/cheapest methods of bridge SHM is long-term tracking of the bridge frequency to identify a change in stiffness. Using data collected from five in-service bridges, this research shows that the user-defined SSI-COV input parameters can significantly impact the quality of extracted natural frequencies. Consequently, a novel method is developed to aid in choosing the inputs used in the SSI-COV method. The method developed also showed that the determined inputs resulted in the extraction of accurate natural frequencies with minimal apparent outliers on all tested bridges. The developed method allows the extraction of quality natural frequencies from low signal-to-noise acceleration data which are vital when undertaking frequency-based SHM.

Traditionally, when a bridge fails an assessment, information required for bridge load capacity may be obtained by fitting a bridge with sensors and measuring the bridge's response to a load of known weight being driven across. Unfortunately, fixing sensors to the bridge is cumbersome and time-consuming, requiring erection scaffolds and platforms and so can be expensive. Camera-based measurements using Unmanned Aerial System (UAS) promise an alternative non-contact approach that is safe, affordable, and fast. However, the lack of stationary locations near bridge mid-span makes it difficult to both measure displacements and stabilise the ego motion of a UAS. To overcome this challenge, this paper therefore presents the experimental validation of method that uses two different cameras mounted on a UAS. One camera is focused on taking measurements near the midspan while another camera is used to stabilise the UAS using stationary locations at the bridge supports. The method does not require that the stationary object is in the field of view of the measurement camera. The method only uses video feed from two cameras viewing different parts of the bridge and no additional sensor information. The significance of this paper to the field of UAS bridge displacement measurements is that the method opens up the ability to measure displacements in locations such as midspans where stationary objects are rare. Submillimetre accuracy was achieved indoors on a model bridge setup and outdoors on a 5 m bridge analogue.

Structural Health Monitoring (SHM) is a technique that involves gathering information to ensure that a structure is safe and behaving as expected. Within SHM, vibration-based monitoring is generally seen as one of the more cost-effective types of monitoring. However, vibration-based monitoring has mostly been undertaken on long-span bridges using data collected with a dense network of sensors. Historically, the logistical difficulty of collecting data on short- and medium-span bridges has meant that the usefulness of vibration-based methods on these bridges is largely unknown. Therefore, this study proposes Minimal Information Data-modelling (MID). MID is an approach that utilises low-cost, easily implementable sensors that are potentially feasible for operators to purchase and operate across a network. This approach will be investigated to determine whether MID is a feasible approach for monitoring short- and medium- span bridges. The results from MID were assessed to determine whether they could detect a suitably small shift in frequency, which is indicative of damage. It was determined that the data models could reliably detect frequency shifts as low as 0.01 Hz. This magnitude of frequency shift is similar to the level of frequency shift reported for a range of bridge damage cases found by others and validated with FE models. The accuracy achieved by the data models indicates that MID could potentially be used as a damage detection method. The cost of the equipment used to collect the data was approximately £370, demonstrating that it is feasible to use MID to monitor bridges across an entire network.

This study examines the typical lateral/racking resistance of cross-laminated timber (CLT).The use of CLT in construction has grown in many regions of the world, not only due to its impressive structural properties but also the improved environmental performance achieved for this mass-timber system compared to more traditional construction materials.In Europe, CLT is primarily manufactured with C24 grade timber or a combination of C24 with small proportions of C16 grade material in internal layers.In many parts of the world, the supply of C24 timber is limited and it is important to establish the structural properties of CLT manufactured with lower-grade material.This study presents a numerical model developed to predict the load-displacement behaviour and structural racking resistance of CLT panels and will inform the experimental testing of CLT panels manufactured from C16 grade material in combination with typical connections utilised in structural mass timber systems.

Cross Laminated Timber (CLT) has been developed in recent years to the stage of automation in production, from timber classification, joining boards, applying adhesive, assembly pressing and CNC machining to form completed CLT panels.Volumetric buildings incorporating CLT are now being developed and completed, showing promising results as sustainable solutions for the construction industry.The majority of European CLT panel manufacturers use grade C24 timber, while countries such as Ireland also have an increasing supply of Sitka Spruce grade C16 timber which has been shown to be suitable for use in CLT.This paper presents elements of a larger research project and focuses on the preliminary design and development of a proposed modular seven-storey building in CLT manufactured from Irish timber, addressing the usage of CLT in volumetric modular construction.Challenges in delivering a building of this type are addressed in terms of building layout, loading arrangement, transportation, and structural design of panels.Design for deconstruction is also considered for the connections between the units to enable future reuse.

The circular use of construction materials is an essential step in the drive to reduce the environmental impact of the construction sector.Structural materials, such as timber, recovered from demolition of buildings is a valuable resource.Reuse or recycling these materials in new buildings products reduces waste and the overall carbon footprint of the build environment.This paper investigates the use of spruce recovered from demolition of a roof structure in the manufacture of CLT panels.Bending tests are performed on 3-layer panels made from this recovered material and also on panels made from new timber and hybrid panels with mixed new and recovered timber.Results show that the performance of CLT panels using recovered timber is equivalent to that of panels from new timber in terms of bending strength and stiffness.

Mode shapes are sensitive to the structural condition of bridges but a reasonable estimate of such changes require several accelerometers, which can be resource intensive. This paper obviates this problem through a novel structure health monitoring (SHM) approach for estimating modal parameters of bridges, including damage-induced changes of boundary conditions by using progressively re-deploying sensors along a monitored bridge. This concept of re-deployable sensors and subsequent use of a series of measurements allow extracting data from different bridge segments and also to get an indication of the condition of the bridge through frequency domain decomposition. Data from different segments are combined to estimate the global mode shape of the bridge and its gradient is observed to be indicative of support stiffness change. The concept is successfully tested through a full-scale field trial on a railway bridge in the Republic of Ireland, before and after the rehabilitation of its supports. The results are expected to guide future on-site measurement of damages due to flooding, scour, and other natural hazards, along with the effectiveness of intervention actions like repair and rehabilitation, providing a clear evidence base for practical value of SHM.

Pairing of robotic arms with precision cutting in the form of laser, plasma, and water jet cutting has opened the door to entirely new forms of structural steel connections that can be assembled with no field welding and minimal (if any) bolting. Such connections can offer increased erection speed, decreased safety issues, and in some cases the opportunity for rapid disassembly, thereby creating a pathway for direct reuse. This paper provides an overview on the testing, numerical modeling, and field assembly of one such connection – the Intermeshed Steel Connection (ISC). This paper highlights features and behaviors of this connection when simulated, tested, and erected in a beam- to-beam connection and focuses on compliance, ability to be designed reliably, load transfer between the side plates and the main member, and the relatively rapid speed of erection compared to a traditional fully bolted connection. Because of its limited number of pieces, the connection may enable in-situ robotic assembly.

This paper presents the work carried out on a collaborative tripartite project between the USA, Republic of Ireland and Northern Ireland to create and investigate the design, development and testing of a new class of intermeshed steel connections (ISCs) that do not rely on field welding and minimise bolting, thus targeting the facilitation of fast disassembly of steel structures and material reuse. This research took advantage of fully automated, precise, advanced manufacturing cutting technologies (e.g. laser, waterjet and high-definition plasma cutting) to achieve a connection method in steel that previously was only possible in materials such as timber, with the potential to revolutionise the steel construction industry. The paper outlines the ongoing research work by the collaborative team, focusing on the design, fabrication, finite-element analysis (FEA) and scaled experimental testing of side ISCs for the flanges of open sections, which included the use of state-of-the-art digital image correlation technology for non-contact measurements. A simplified connection design procedure is presented based on yielding of the side plates. This design procedure is refined based on the results of experimental testing and FEA of the local axial behaviour of the flange connection, addressing stress concentrations in the flange, fabrication tolerances and material overstrength.

One structural health monitoring method used to detect the occurrence of structural damage is the tracking of a structure's natural frequencies. However, for bridges, this is complicated by the changing environmental and operational conditions, which also have an effect on the natural frequencies. Consequently, much of the research effort has been on trying to develop data-modelling approaches that correct for, or remove, environmental effects so that changes in structural behaviour can be revealed. However, the fact that the process of extracting frequencies from bridge response data sets has in itself some inherent uncertainties that have been largely ignored forms the major interest of this study. In this paper, various methods for extracting frequency data from time-domain signals are reviewed, and their suitability for use in automated approaches is discussed. A selection of these methods was then used to obtain frequencies from continuous acceleration data from a bridge over a 20 d period. Comparisons were then made between the obtained frequencies, and any observed differences are highlighted between the methods.

A recent survey of Europe's highway infrastructure has concluded that almost half of Europe's bridges are nearing the end of their design live. Work in the wider Structural Health Monitoring sector is aiming to develop reliable and cost-effective methods for verifying condition, remaining service life and safety of ageing structures. Most bridge condition assessment methods are based on deflection, acceleration or strain measurements. This paper looks at the possibility of using rotation measurements as a main parameter to identify damage. This study looks at numerical analyses of a moving point load on a one-dimensional bridge model to provide the theoretical basis of the proposed damage detection method. It is shown that when local damage occurs, even when it is remote from a sensor location, it results in an increase in the magnitude of rotation measurements. This study looks at how best to exploit this fact for damage detection. In the study a number of damage scenarios, sensor locations, and load arrangements are investigated, and their influence on the ability of the algorithm to detect damage are reported.

A recent survey of Europe's highway infrastructure has concluded that almost half of Europe's bridges are nearing the end of their design live. Work in the wider Structural Health Monitoring sector is aiming to develop reliable and cost-effective methods for verifying condition, remaining service life and safety of ageing structures. Most bridge condition assessment methods are based on deflection, acceleration or strain measurements. This paper looks at the possibility of using rotation measurements as a main parameter to identify damage. This study looks at numerical analyses of a moving point load on a one-dimensional bridge model to provide the theoretical basis of the proposed damage detection method. It is shown that when local damage occurs, even when it is remote from a sensor location, it results in an increase in the magnitude of rotation measurements. This study looks at how best to exploit this fact for damage detection. A number of damage scenarios, sensor locations, and load arrangements are investigated in this study and their influence on the ability of the algorithm to detect damage are reported.