Flanking sound transmission through cross laminated timber junctions with elastic interlayers: prediction model and validation

Cross-laminated timber (CLT) has experienced significant growth in popularity due to among others high structural stiffness and low weight.However, these two properties lead to potentially poor sound insulation.In order to suppress flanking sound, where vibrational energy is transmitted from one wall or floor to another through their common junction, elastic interlayers are typically employed, but the potential improvements are not straightforward to predict.In the present work, the vibration reduction index K ij for wave transmission between two connected elements i and j is predicted based on analytical wave theory for semi-infinite thin homogeneous orthotropic plates.The junctions can be rigid or they can contain elastic interlayers modeled as distributed springs or flexible waveguides.The proposed methodology is validated with on-site experiments on a T-junction consisting of CLT-panels with a resilient interlayer.Static equivalence is used to obtain the model input parameters.The model predictions are in reasonable agreement with the experimental results for the entire frequency range, especially for the flexible interlayer models.The differences between the equivalent isotropic and orthotropic plate model predictions remain small.