Horizontal stiffening of multi-story timber buildings
No Thumbnail Available
Insinööritieteiden korkeakoulu | Master's thesis
Master's Programme in Building Technology (CIV)
AbstractEven though wood has always been available to be used in construction timber has been used to build only one-to-three story buildings until recent years. Main reasons have been fires in large cities in the past and defects of wood such as knots and cracks that have limited the reliability of timber as a material. In recent years many engineering innovations have been made among the timber industry such as CLT and LVL. In these new materials the homogeneity of timber has been increased as well as the material properties by removing the defects and combining defect less pieces back together. New materials have induced also new kind of problems to be tackled. Since the urbanization and acceleration of human population growth has increased more and more multi-story timber buildings built are larger or taller than previous ones. Timber as light weight material has low capability for vibration dissipation and thus flanking noises from adjacent apartments are transmitted through building structure. To tackle the problem rubber based insulation layers are today used between the elements and in the connectors to limit the vibration transmission. Use of rubber causes walls to behave non-linearly and its effects to building stiffness is unknown. Since the connections of timber buildings are already flexible compared to connections of steel and concrete buildings the use of rubber may became a problem. The aim of this study is to find information how the behavior of rubber could be modelled and how important it is for wall deformation. The deformations of walls with and without rubber interlayer between elements and under connectors are evaluated with two connection types. As another goal finding an efficient way to compare wall deformation between different connections by hand was defined. Calculations are based on spring chains representing connections stiffnesses and rigid body rotation of the wall. Results are verified with FEM analysis. Additionally, the rubber interlayer effect to accelerations on top floor is compared to wall without rubber.
Thesis advisorLänsiluoto, Jaakko
multi-story timber building, shear wall, sound insulation interlayer, wall deformation, acceleration, vibration