Flanking paths between walls and lightweight wood frame floors using statistical energy analysis

Abstract

Previous work has examined flanking paths from a floor/ceiling assembly to a load-bearing wall (where the floor joists were oriented normal to the supporting wall). It was shown that beams at the joint (plates and joist header) must be considered when predicting transmission at this type of joint. The dominant flanking path was from the floor deck to the supporting wall which reduced the apparent sound insulation from FSTC 59 to 53. The path from the upper to the lower wall was insignificant. This paper presents the results of a similar study that examined flanking paths from a nominally identical floor/ceiling assembly to a non-load-bearing wall (where the joists were parallel to the joint axis). Measured velocity level differences and apparent sound insulation are compared to the load-bearing wall configuration. Flanking paths involving a non-load-bearing wall are shown to have no appreciable impact. Joint models are presented using both standard wave methods and dynamic stiffness methods. The joint models are incorporated into a statistical energy analysis model of the system. Measured and predicted results for the two joint configurations are compared and show good agreement between 100–3150 Hz.