The behavior of cross-laminated timber and reinforced concrete floors in a multi-story building

Abstract

The behavior of cross-laminated timber (CLT) and reinforced concrete (RC) floors in a multi-story building is investigated in this paper. The load-bearing capacity, fire resistance, and sound insulation characteristics of the floors are the main focus of this research. In order to achieve this goal, a four-story building having RC floors is modeled, analyzed, and designed using the StruSoft FEM-Design software (FEM) following the Eurocodes and Swedish national annex. The building is considered to be in the city of Gävle in Sweden. Then, the RC floors of the building are replaced with the CLT floors, and the same process is done utilizing FEM. The utilization ratios (the ratios of the applied loads to the load-bearing capacities), vertical deflections, weights of the RC and CLT floors, and reaction forces of the buildings are evaluated and compared. The results show that the RC floors meet the deflection requirements well which contributes to the focus on their utilization ratios. The designed RC floors are acceptable from the vertical deflection and utilization ratio perspectives. However, the CLT floors cannot meet the vertical deflection requirements, and thus, need strengthening. The CLT floors are strengthened with supporting timber beams and columns which result in acceptable vertical deflections and utilization ratios. Fire resistance and sound insulation conditions of the RC and CLT floors are assessed by calculations based on the requirements of the Swedish National Board of Housing, Building, and Planning regulations (BBR) as well. The RC floors have the ability to be soundproof and have no difficulties in meeting the fire resistance requirements R60 of BBR. A cross-section is proposed for the CLT floors which can meet the fire resistance requirement R60 and sound insulation requirement C of BBR. The maximum reaction forces of the buildings and total weights of the floors are larger in the case of RC than CLT.