## 3 Research Method
It is important to note that a 'timber' building can combine non-timber connections in certain areas among timber members, as in the case of Lighthouse Joensuu [75]. On the contrary, in composite or hybrid types encompassing timber, an extensive share of the structural framework includes materials other than timber, notably steel, concrete, or a blend of both. In buildings amalgamating timber and concrete, it is frequent to observe a concrete core supporting a timber structure, as demonstrated by [PERSON] [76; 77]. Alternatively, in buildings merging timber and steel, an extensive share of the structure relies on steel, as evidenced by Tallwood 1 at District 56 [78]. Analogously, a hybrid category integrating timber, concrete, and steel utilizes an amalgamation of all three materials to bear main forces. A common pattern encompasses a concrete service core working alongside steel beams and columns, whereas timber is employed in separation walls as in the case of De Karel Doorman in Netherlands [79]. In the realm of enhancing lateral stiffness in high-rise buildings, especially concerning challenges like wind and earthquake forces, numerous load-bearing systems and categorizations have been applied in real-world situations and scrutinized within the existing literature [80]. In this paper, the authors used the structural system categorization proposed by [33] owing to its complete coverage: (i) rigid-frame system; (ii) shear-frame system including shear-trussed frame and shear-walled frame systems; and (iii) shear-wall system, as seen in Figure 3.  
Figure 2: Case studies from various locations on the world map (image created by authors). Moreover, it is noteworthy to highlight that, in the realm of timber construction, configurations pertaining to structural integrity such as outriggered frames [79; 80], assorted tube systems (comprising framed, diagrid-framed, trussed, and bundled tubes) [81; 82], as well as buttessed cores [83; 84] predominantly find application in buildings of extraordinary height exceeding 300 m. These systems are favored due to their efficacy and economic viability. Therefore, these load-bearing systems were omitted from consideration in our study, as its focus lies on tall buildings rather than exceptionally tall ones. Nevertheless, as illustrated by the case of Treet (Figure 4) in Norway [85; 86], there exists a singular instance of a timber-based residential high-rise structure incorporating a tube system. Space efficiency concerns the relationship between net floor area (NFA) and GFA. Spatial effectiveness has considerable importance, notably for stakeholders, as it involves the efficient utilization of floor plan regions to realize maximal returns on financial commitments. The level of spatial effectiveness predominantly depends on diverse factors, such as the selection of structural frameworks and architectural design [25]. Figure 4: Treet (photo courtesy of ARTEC). Figure 3: High-rise timber tower load-bearing systems (image created by authors). In the methodology of this manuscript, the evaluation of spatial effectiveness was performed by computing the ratio of NFA to GFA, furnishing a quantitative gauge of the efficiency of space utilization. Concurrently, the computation of core relative to GFA entailed assessing the proportion of the service core to GFA, providing perspectives into the proportional distribution of space allocated to fundamental structural and service elements within the comprehensive building framework. The computation of spatial effectiveness encompasses two primary ratios [26; 27]: NFA to GFA and core to GFA. NFA is derived by deducting the service core area from GFA. This deduction aids in isolating the functional zones where activities occur, excluding areas designated for infrastructure and auxiliary services. The ratio of NFA to GFA offers a quantitative assessment of the efficiency with which the accessible floor area is utilized for practical purposes, indicating the effectiveness of space distribution.