Modular timber construction embodies a pioneering and eco-friendly methodology within the building sector. With the notable progress made in manufacturing technologies and the advent of engineered wood products, timber has evolved into a promising substitute for conventional materials such as concrete, masonry, and steel. Beyond its structural attributes, timber brings environmental advantages, including its inherent capacity for carbon sequestration and a reduced carbon footprint compared to conventional materials. Timber’s lightweight nature, coupled with its versatility and efficiency in factory-based production, accelerates modular construction processes, providing a sustainable solution to the growing demands of the building industry. This work thoroughly explores contemporary modular construction using wood as the primary material. The investigation spans various aspects, from the fundamentals of modularity and the classification of modular timber solutions to considerations of layout design, structural systems, and stability at both the building and module levels. Moreover, inter-module joining techniques, MEP (mechanical, electrical, and plumbing) integration, and designs for disassembly are scrutinized. The investigation led to the conclusion that timber modular construction, drawing inspiration from the steel modular concept, consistently utilizes a structural approach based on linear members (timber frame, post-and-beam, etc.), incorporating stability configurations and diverse joint techniques. Despite the emphasis on modularization and prefabrication for adaptability, a significant portion of solutions still concentrate on the on-site linear assembly process of those linear members. Regarding modularity trends, the initial prevalence of 2D and 3D systems has given way to a recent surge in the utilization of post-and-beam structures, congruent with the ascending verticality of buildings. In contrast to avant-garde and bold trends, timber structures typically manifest as rectilinear, symmetric plans, characterized by regular and repetitive extrusions, demonstrating a proclivity for centrally located cores. This work aims to offer valuable insights into the current utilization of modular timber construction while identifying pivotal gaps for exploration. The delineation of these unexplored areas seeks to enable the advancement of modular timber projects and systems, fully leveraging the benefits provided by prefabrication and modularity.

The present chapter examines different types of lateral-load-resisting systems (LLRSs) for taller timber buildings (TTBs). The LLRSs are presented with specific reference to their role in the seismic response of TTBs, and have been classified according to the main structural elements composing them. Therefore, timber-framed LLRSs, consisting of one-dimensional members, are first examined, followed by panelised LLRSs, featuring two-dimensional elements; mixed timber-framed and panelised LLRSs are then addressed. Next, hybrid timber-steel and -concrete, as well as volumetric modular LLRSs, are presented. Finally, a separate section is dedicated to the interaction of timber diaphragms with LLRSs in TTBs. Besides a comprehensive literature review, for each LLRS type, relevant examples of buildings realized in practice have been reported. In the final section, based on the analysed research studies from literature, the main future challenges and research directions for an effective, holistic design of LLRSs in TTBs, are addressed.

The structural design of volumetric modular systems made of cross-laminated timber (CLT) faces unique challenges when resisting lateral loads. In current practice, the lateral stability of Integrated Volumetric Modular Systems (IVMS) is often ensured by friction between module interfaces, while connections primarily serve assembly purposes. Although this approach can provide sufficient resistance under wind loading, it becomes inadequate under seismic conditions, where higher load intensities and cyclic reversals demand more reliable load transfer mechanisms. This study explores an alternative strategy for achieving high-performance Lateral Load Resisting Systems (LLRSs) in modular CLT buildings by integrating conventional mechanical connectors, such as hold-downs, tie-downs, and angle brackets, into the inter-modular interfaces. The proposed system transforms the load path from a friction-based to a mechanically anchored mechanism, enabling the activation of continuous multi-storey shear walls across modules. Numerical analyses on a representative mid-rise modular building demonstrate that the proposed configuration significantly enhances global stiffness, reduces interstorey drift, and ensures a stable load transfer under seismic loading. Moreover, a feasibility assessment confirms that the proposed solution can be implemented within standard modular construction procedures. The results establish a promising foundation for the development of robust and constructible LLRS strategies for modular CLT buildings in seismic-prone regions.