The dynamics of beams equipped with tuned mass dampers is of considerable interest in engineering applications. Here, the purpose is to introduce a comprehensive framework to address the stochastic response of the system under stationary and nonstationary loads, considering inertia effects along the spring of every tuned mass damper applied to the beam. For this, the key step is to show that a tuned mass damper with spring inertia effects can be reverted to an equivalent external support, whose reaction force on the beam depends only on the deflection of the attachment point. On this basis, a generalized function approach provides closed analytical expressions for frequency and impulse response functions of the system. The expressions can be used for a straightforward calculation of the stochastic response, for any number of tuned mass dampers. Numerical results show that spring inertia effects may play an important role in applications, affecting considerably the system response.

The reverse logistics (RL) performance of construction and demolition waste (C&DW) differs significantly between countries. Although some countries are successfully circular, other countries are still far behind; with C&DW being largely directed to landfills or being illegally dumped. There is a lack of guidelines on the requirements for transitioning countries towards C&DW diversion, and little attention has been given to the factors that influence the success of C&DW RL and increased circularity. This study aims to develop a framework that helps in structuring and assessing the success of C&DW RL on a regional level and serves as a guide for transitioning developing countries towards implementing such operations. Since the framework should help evaluate where interventions are needed to enhance performance, the exact domains to be used and their priorities should be identified. A systematic literature review was conducted to identify the critical factors that affect the outcome of RL operations. After their identification, the interrelationships between the factors and the dependence and driving power of each are examined through interpretive structural modelling. This analysis provides valuable insights and thus, allows for the establishment of a hierarchy of factors that can serve as a guide for decisionmakers. The developed framework can be utilized for enhancing the efficiency of current RL operations as well as for identifying the direction of action and efforts needed to shift developing countries towards the implementation of circular economy in the sector of C&DW.

Resource depletion and climate change, amongst others, are increasingly worrying environmental challenges for which the road engineering sector is a major contributor. Globally, viable solutions that comply with the principles of circular economy (CE) are being investigated that can replace conventional asphalt mixtures in a post-fossil fuel society. The use of reclaimed asphalt (RA) is a widely used and well-established method to reduce the environmental and economic impacts of asphalt mixtures while increasing their circularity. However, RA's market supply and demand have not yet been systematically analyzed and established. Moreover, the actual circularity potential and the opportunity of re-circulating RA in a closed-loop model have not yet been methodically defined. To address this, a three-layered framework to quantify and assess the circularity potential (Ω) of RA has been developed. To give stakeholders and legislative bodies a simple method to assess the opportunities available to them to become “more circular”, a novel equation has been formulated. This takes the form of a three-level indicator that considers: technical aspects, the effect of the RA market, and the legislative restrictions. A case study in Germany was structured and undertaken to develop and verify the proposed approach. The results indicate that the available RA is insufficient to cover the needs of asphalt mixture production; even though RA production is significantly lower than the actual need of asphalt mixtures, it is not utilized in its entirety. An impactful step forward is the alteration of the regulations to support the higher utilization of RA in asphalt mixtures, and subsequently, the increased circular opportunity and potential of RA. Thus, Circularity potential (Ω) is a composite indicator that can support stakeholders, designers, and asset managers during the process of decision-making, to follow more circular operational, design, and asphalt pavement management patterns.

This contribution considers a virtual experiment on the vibrational response of rail and road bridges equipped with smart devices in the form of damping elements to mitigate vibrations. The internal damping of the bridge is considered a discontinuity that contain a dashpot. Exact complex eigenvalues and eigenfunctions are derived from a characteristic equation built as the determinant of a 4 × 4 matrix; this is accomplished through the use of the theory of generalized functions to find the response variables at the positions of the damping elements. To relate this to real world applications, the response of a bridge under Poisson type white noise is evaluated; this is similar to traffic loading that would be seen in a bridge’s service life. The contribution also discusses the importance of smart damping and dampers to sustainability efforts through the reduction of required materials, and it discusses the role played by robust mathematical modelling in the design phase.

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