Serviceability performance studied covers three different performance attributes of a building. These attributes are 1) vibration of the whole building structure, 2) vibration of the floor system, typically in regards to motions in a localized area within the entire floor plate, and 3) sound insulation performance of the wall and floor assemblies. Serviceability performance of a building is important as it affects the comfort of its occupants and the functionality of sensitive equipment as well. Many physical factors influence these performances. Designers use various parameters to account for them in their designs and different criteria to manage these performances. Lack of data, knowledge and experience of sound and vibration performance of tall wood buildings is one of the issues related to design and construction of tall wood buildings.
In order to bridge the gaps in the data, knowledge, and experience of sound and vibration performance of tall wood buildings, FPInnovations conducted a three-phase performance testing on the Origine 13-storey CLT building of 40.9 m tall in Quebec city. It was the tallest wood building in Eastern Canada in 2017.
The ambient movement of three modern multi-storey timber buildings has been measured and used to determine modal properties. This information, obtained by a simple, unobtrusive series of tests, can give insights into the structural performance of these forms of building, as well as providing information for the design of future, taller timber buildings for dynamic loads. For two of the buildings, the natural frequency has been related to the lateral stiffness of the structure, and compared with that given by a simple calculation. In future tall timber buildings, a new design criterion is expected to become important: deflection and vibration serviceability under wind load. For multi-storey timber buildings there is currently no empirical basis to estimate damping for calculation of wind-induced vibration, and there is little information for stiffness under wind load. This study therefore presents a method to address those gaps in knowledge.
Proceedings of the Institution of Civil Engineers - Construction Materials
Cross-laminated timber has, in the last 6 years, been used for the first time to form shear walls and cores in multi-storey buildings of seven storeys or more. Such buildings can have low mass in comparison to conventional structural forms. This low mass means that, as cross-laminated timber is used for taller buildings still, their dynamic movement under wind load is likely to be a key design parameter. An understanding of dynamic lateral stiffness and damping, which has so far been insufficiently researched, will be vital to the effective design for wind-induced vibration. In this study, an ambient vibration method is used to identify the dynamic properties of a seven-storey cross-laminated timber building in situ. The random decrement method is used, along with the Ibrahim time domain method, to extract the modal properties of the structure from the acceleration measured under ambient conditions. The results show that this output-only modal analysis method can be used to extract modal information from such a building, and that information is compared with a simple structural model. Measurements on two occasions during construction show the effect of non-structural elements on the modal properties of the structure.
This article outlines the structural design approach used for the Brock Commons Student Residence project, an 18-storey wood building at the University of British Columbia in Vancouver, Canada. When completed in summer 2017, it will be the tallest mass timber hybrid building in the world at 53 meters high. Fast + Epp are the structural engineers, working in conjunction with Acton Ostry Architects and Hermann Kaufmann Architekten. Total project costs, inclusive of fees, permits etc. are $51.5M CAD.
Key point to development of environmentally friendly timber structures, appropriate to urban ways of living, is the development of high-rise timber buildings. Comfort properties are nowadays one of the main limitations to tall timber buildings, and an enhanced knowledge on damping phenomena is therefore required, as well as improved prediction models for damping.
The aim of this work has consequently been to estimate various damping quantities in timber structures. In particular, models have been derived for predicting material damping in timber members, beams or panels, or in more complex timber structures, such as floors. Material damping is defined as damping due to intrinsic material properties, and used to be referred to as internal friction. In addition, structural damping, defined as damping due to connections and friction in-between members, has been estimated for timber floors.
The following paper describes the first stage of dynamic testing of a post-tensioned timber building to be performed in the structural laboratory of the University of Basilicata in Potenza, Italy as part of a series of experimental tests in collaboration with the University of Canterbury in Christchurch, New Zealand. During this stage of testing a 3-dimensional, 3-storey post-tensioned timber structure will be tested. The specimen is 2/3rd scale and made up of frames in both directions composed of post-tensioned timber. The specimen will be tested both with and without the addition of dissipative steel angles which are designed to yield at a certain level drift. These steel angles release energy through hysteresis during movement thus increasing damping. The following paper discusses the testing set-up and preliminary numerical predictions of the system performance. Focus will be placed on damping ratios, displacements and accelerations.
March 29-31, 2012, Chicago, Illinois, United States
This paper describes initial experimental testing to investigate feasible sources of passive damping for the seismic design of post-tensioned glue laminated timber structures. These innovative high performance structural systems extend precast concrete PRESSS technology to engineered wood structures, combining the use of post-tensioning bars or cables with large post-tensioned timber members. The combination of these two elements provides elastic recentering to the structure while the addition of damping using a specialised energy dissipation system gives the desirable `flag shaped' hysteretic response under lateral loading. Testing has been performed on a full scale beam-column joint at the University of Basilicata in Italy in a collaborative project with the University of Canterbury, New Zealand. The experimental testing uses engineered wood products, extending the use of laminated veneer lumber (LVL) structures tested in New Zealand to testing of glue laminated timber (glulam) structures in Italy. Current testing is aimed at further improvement of the system through additional energy dissipation systems.
This report summarizes the results of our ground motion evaluation for the proposed FRMWRK Office building to be constructed at 430 NW 10th Avenue in Portland, Oregon. Our geotechnical report for the project was submitted on November 30, 2015 (GeoDesign, 2015). The site is shown relative to surrounding features on Figure 1...