When facing the increasing demands of the housing market and balancing the requirements of sustainable development in the construction sector, building design methods should practise material conservation and adopt carbon reduction measures to alleviate the current environmental burden through the implementation of a circular economy approach. Volumetric modular timber design is recognised as a practical application to test the feasibility of a waste-reduced approach. Driven by the aim of further improving volumetric modular timber construction and increasing its use in a circular economy framework, this paper presents a case study review of 60 modular timber building projects constructed using volumetric modules. The dimensions, the architectural and structural design, and the manufacturing and assembly processes of the three-dimensional modular units were assessed to explore their potential for contributing to a circular built environment. The results show that the similarly sized modular volumetric timber units have the potential to serve different functions, and to be reused in subsequent projects. The stacking design allows modular volumetric units to be reused in a way that supports function conversion and satisfies project coordination criteria. The case studies illustrate that modular timber buildings are increasingly used for flexible design solutions, and to meet carbon emission reduction targets. The analysis results can address prevalent misconceptions regarding modular wood construction, provide interested parties with a better understanding, and promote the use of modular volumetric timber units in general.

The model of the 2–2 type cement-based piezoelectric sensor, which is connected with a resistor while under the impact mechanical load, is established in this article. The dynamic theoretical expressions are acquired by utilizing the separation variable method and the matrix coefficient method and then used to analyze and discuss the electrical properties and the influence of the resistance value, which is verified correctly by numerical analysis. Also, the effect of resistor value and different material parameters on dynamic properties of such sensor is further investigated. And a reverse voltage is proposed to balance the displacement of the free-end and the stress of the fixed-end to enhance the safety. At last, the acoustic impedance ratio associated with the compatibility of the composite is discussed. The conclusions discussed in this work could provide some theoretical references for optimizing the design of the 2–2 cement-based piezoelectric sensor connected to electrical components in practical application.

Multilayer metallic plate is made by stacking homogeneous or heterogeneous metallic plates and connecting them with fasteners. The air-gap thickness between the adjacent layers affects the performance of the plate structure. The eddy current testing (ECT) technology has been used for the nondestructive testing of multilayer plate. However, the effect of air gap on the characteristics of eddy current (EC) attenuation in multilayer plate remains unclear and the study of the relation between the response of the EC probe and the gap thickness is very limited. The computation results of the paper show that the air gap in a double-layer plate reduces the amplitude of EC density in the bottom layer and decreases the rate of EC attenuation in the top layer. The mechanism is revealed. The effect of gap thickness on probe response is investigated. It is found that the presence of air gap makes the EC response either larger or smaller, depending on the working frequency. The reason is explained based on the characteristics of EC attenuation. Thereupon, the experiment of measuring gap thickness using the ECT is carried out.

Modular timber construction offers a strong potential for circularity, but structural engineering workflows remain project-specific, documenting modular buildings as conventional assemblies of individual members. Structural verification is repeated for each project, and structural information is not retained in a transferable form that would enable component reuse. This paper proposes a hierarchical structural documentation framework that reorganises verification and documentation across building, component, and connection levels. The framework combines reduced-order modelling with code-compliant capacity envelopes to generate a structural component passport containing certified performance and lifecycle information. A portal frame case exemplifies the approach compared to a conventional documentation workflow and shows how reusable structural performance data can support traceability, reduce repetitive engineering effort, and enable structural reuse.