Effect of Bearing Direction and Mounting Techniques on Cross-Laminated Timber Elements in the Field

Abstract

Vibration reduction index (Kij) measurements in the field have some challenges compared to laboratory measurements. Firstly, the measurement requires access to a construction site during the short time span when the cross-laminated timber (CLT) elements are apparent. Secondly, building contractors are often on a tight time schedule. Therefore, it is important to find a solution that minimizes the measurement time on site. Moreover, Kij measurements in the field include several types of junctions with different bearing directions which may be of importance. This paper aims to evaluate two different mounting techniques with accelerometers on CLT elements and to discuss how the bearing direction could affect the vibration level difference of junctions. Measurement data indicates few deviations between mounting techniques with bee wax or double-sided adhesive tape when accelerometers are attached on CLT elements. Furthermore, field measurements indicate that the vibration level will decrease with an increased number of lamellas over the same CLT element. Double-sided adhesive tape is an adequate substitute for bee wax in the field for mounting accelerometers on CLT elements, with some limitations for high frequencies. Measurement data concludes that the bearing direction of CLT elements can influence the vibration reduction index of a junction.