The increasing demand for sustainable and high-rise buildings has led to the development of hybrid concrete-timber structures. These buildings incorporate a concrete core and columns for stability, combined with timber and concrete floor systems, providing an opportunity to balance sustainability, structural efficiency, and cost-effectiveness. While this approach presents opportunities, it also introduces several challenges related to structural dynamics, fire safety, environmental impact, and construction costs.

A key issue in concrete-timber hybrid buildings is their lower weight due to timber floors that are lighter than concrete floors, which makes them more susceptible to wind-induced vibrations. Additionally, the irregular mass distribution caused by alternating timber and concrete floors over the height of the building influences the dynamic response of the building. From an environmental perspective, timber is often regarded as a sustainable material due to its carbon storage capability. However, the extent to which hybrid systems reduce overall carbon emissions compared to concrete buildings remains uncertain. Furthermore, construction costs are closely tied to structural and environmental performance, impacting the feasibility of such buildings.

Despite growing interest in hybrid concrete-timber high-rises, existing research lacks an integrated approach that examines the relationships between dynamic behavior, environmental impact, and construction cost. Although individual aspects have been studied, the correlation between these design factors remains unclear. Additionally, the influence of parameters such as building height, floor type, and concrete-timber distribution on these design aspects has not been extensively explored.

This research aims to support the integral design of hybrid concrete-timber high-rises by offering a structured approach to evaluating key design choices and their implications. The findings contribute to a more holistic approach to hybrid building design, supporting designers, policymakers, and researchers in optimizing hybrid systems.

This thesis explores the influence of key building parameters on the design aspects of tall concrete-timber buildings during the early design phase. The goal is to identify relationships between dynamic behavior, environmental performance, and building cost by analyzing various building variants. The studied parameters include building height, floor plan, floor type, and the percentage of concrete floors. To achieve this, three hypotheses are formulated that connect the design aspects with the percentage of concrete floors. By analyzing different percentage of concrete in the floor systems, the study aims to provide insights into the complex interactions between these aspects.

The methodology consists of three parts. First, building variants are designed based on predefined parameters, using structural calculations for floor systems, concrete cores, and foundations. Second, models are developed to determine the dependent variables: dynamic behavior (first natural frequency), environmental performance (Environmental Cost Index through Life Cycle Assessment), and construction cost. Based on the results of the models relationships between independent and dependent variables are analyzed to identify trends and interactions. Finally, correlations between the three design aspects are examined to provide insights into their interdependencies.

The results indicate that building height is the most significant factor influencing dynamic behavior, environmental performance, and construction cost. This is evident from the distinct scatter plots for each building height. The ECI value for buildings between 70 and 90m ranges from 12 to 28 €/m², while for buildings of 110m, it ranges from 20 to 33 €/m². Construction costs for buildings between 70 and 90m range from 735 to 875 €/m², and between 850 and 1000 €/m² for buildings of 110m. By analyzing the results, no significant correlation between construction cost and other parameters was found, as the effect ranges of the parameters are similar. Moreover, the dynamic behavior of the buildings remains within safe limits. Additionally, variations in foundation piles and core dimensions significantly impact the environmental cost index (ECI) and construction cost, making their inclusion essential for accurate comparisons. Finally, the model effectively analyzes specific parameters, thereby providing clear insights into their influence on design aspects.