## 4 Results
### Main Structural Design Parameters: Structural Material and Structural System  
Figure 7 highlights a significant instance of pure timber assembly, constituting 53% of the data set, whereas composite structures follow closely, representing 47% within a collection encompassing 51 high-rise residential timber structures. \begin{table}
\begin{tabular}{c c c c c} \hline \hline  & **Our Findings** & \begin{tabular}{c} **Mixed-Use** \\ **Skyscrapers** [25] \\ **(64 Cases)** \\ \end{tabular} & \begin{tabular}{c} **Residential** \\ **Skyscrapers** [26] \\ **(27 Cases)** \\ \end{tabular} & \
\begin{tabular}{c} **Office** \\ **Skyscrapers** [27] \\ **(44 Cases)** \\ \end{tabular} \\ \hline Core & Central (55\%) & \multirow{2}{*}{Central (100\%)} & Central (93\%) & Central (95\%) \\ \hline planning & Peripheral (45\%) & & Peripheral (7\%) & External (5\%) \\ \hline \multirow{4}{*}{
\begin{tabular}{c} Building \\ form \\ \end{tabular} } & Prismatic (78\%) & Prismatic (17\%) & Prismatic (56\%) & Prismatic (21\%) \\ \cline{1-1} \cline{3-5}  & Prismatic (78\%) & Setback (17\%) & Setback (11\%) & Setback (18\%) \\ \cline{1-1} \cline{3-5}  & Free (22\%) & Tapered (38\%) & Tapered (11\%) & Tapered (27\%) \\ \cline{1-1} \cline{3-5}  & & Twisted (1\%) & Twisted (7\%) & Twisted (2\%) \\ \cline{1-1} \cline{3-5}  & & Free (27\%) & Free (15\%) & Free (32\%) \\ \hline \hline \end{tabular}
\end{table} 
Table 1: Comparison of core planning and building form. Figure 6: Case studies categorized by building form. Figure 7: Case studies categorized by structural material. In European high-rise residential wooden constructions, wood is preferred due to proximity to woodlands, sustainability goals, and cost savings [88]. Availability of indigenous wood supports sustainability. Wood construction helps reduce carbon emissions and aligns with Europe's sustainability objectives. Its suitability for tall buildings, ease of construction, and environmental benefits make it a favored choice for many European projects. Figure 8 depicts composite configurations characterized by the amalgamation of load-bearing components. Timber paired with concrete emerged as the prevailing preference, comprising 67% of occurrences. Subsequently, timber used with both concrete and steel is noted in 21% of instances. Conversely, timber used with steel is the least common, manifesting in merely three occurrences. In hybrid configurations, incorporating concrete in the core element offers several advantages. Firstly, it boosts the overall transverse stiffness and durability, addressing structural needs [89]. Secondly, it enhances fire resilience due to concrete's properties. Thirdly, concrete helps dampen vibrations caused by wind forces, common in tall buildings [80]. Notably, timber and concrete hybrid techniques benefit from concrete cores, significantly improving transverse rigidity [90]. Additionally, including concrete cores in architectural plans, exemplified by the Brock Commons Tallwood House project, simplifies authorization processes [91]. This ease can be attributed to the widespread use of concrete cores in traditional skyscrapers. Crucially, in this context, fire escape staircases are housed within concrete cores, ensuring their non-flammable construction. Illustrated in Figure 9, shear-frame systems are favored, utilized at a frequency of 57%, followed by the shear-wall mechanism, constituting 41% of cases. Concerning shear-frame systems, shear-walled frames are primarily used, totaling 26 instances, with a significant lead. Figure 8: Composite case studies categorized by structural material combinations. Figure 9: Case studies categorized by structural system. In shear-frame systems, which include shear-trussed frame and shear-walled frame setups, the drawbacks of rigid frames compared to shear trusses or walls, and the limitations of shear trusses or walls compared to rigid frames, are balanced out when used together [92]. For instance, Ascent, the tallest timber building, demonstrates this synergy. This explains why shear-frame systems are commonly used.