Project contact is Jianhui Zhou at the University of Northern British Columbia
Summary
Building acoustics has been identified as one of the key subjects for the success of mass timber in the multi-storey building markets. The project will investigate the acoustical performance of mass timber panels produced in British Columbia. The apparent sound transmission class (ASTC) and impact insulation class (AIIC) of bare mass timber elements as wall and/ or floor elements will be measured through a lab mock-up. It is expected that a database of the sound insulation performance of British Columbia mass timber products will be developed with guidance on optimal acoustical treatments to achieve different levels of performance.
In many mass timber buildings, CLT or nail laminated timber (NLT) floors are designed with a concrete topping to improve acoustic separation, reduce vibration or act as a fire barrier. Little research has examined the fire behavior of these floor systems, but some preliminary tests involving LVL show that they may be able to meet three-hour fire resistance ratings, which could potentially open up the use of mass timber in Type I buildings, representing a large market opportunity. This project will test the behavior of composite floors under fire loading conditions considering the following parameters: shear connector type, mass timber panel types and thicknesses and concrete thicknesses. It will also test and validate an innovative fire research methodology using radiant panels.
Facilitation of Acoustics Testing for Sustainable Mass Timber Technologies, Leading to Publication of Open Source Acoustics Data for Standard Acoustics Scenarios
Project contact is Kevin Van Den Wymelenberg at the University of Oregon
Summary
Our aim is to support the acceptance and increase market share of sustainable mass timber construction technologies such as Cross Laminated Timber (CLT), Mass Plywood Panel (MPP), Glue Laminated Timber (GLT), and Nail Laminated Timber (NLT), by lowering or eliminating barriers due to lack of acoustics data for mass timber construction assemblies. Currently, sustainable mass timber projects carry the cost of required acoustics testing, impairing their economic feasibility. With our new acoustics testing facility, testing supported by this grant will produce common acoustics data on the assemblies most in market demand. These data will be hosted in an online open-access database, supporting rapid growth in this industry. Increasingly specialized testing scenarios will be more easily accommodated, as this facility is located closer to USFS source materials and production facilities than currently operating facilities and is designed specifically for the specialized requirements of testing mass timber assemblies. Since sustainable mass timber technologies allow increased utilization of lower quality timber, and timber with insect damage, increasing the market share of mass timber will increase utilization of USFS timber, specifically that which might otherwise remain on-site unused. With removal of this type of timber, fire load will be lessened as well. Initial testing supported by this grant will include mass timber assemblies constructed with lower quality and smaller dimension timber.
Project contact is Shiling Pei at the Colorado School of Mines
Summary
Nail and Dowel Laminated Timber (NLT and DLT) are efficient technologies to build mass timber floor systems directly out of dimension lumber. It is relatively inexpensive to construct and has substantial potential to help expand the mass timber building market, particularly when the floor spans mainly in one direction. There have been multiple NLT projects constructed in the seismic region, which represents a large portion of the CLT construction market. The lateral design of NLT/DLT floor systems is currently based on very conservative assumptions (essentially equating its performance to a traditional joist-sheathing light-frame wood floor system) due to this lack of validated performance examples. This project will systematically demonstrate the potential of NLT/DLT floor systems under extreme lateral loads through component level testing and full-scale building level shake table tests. Through collaboration with manufacturers and designers (StructureCraft and Magnusson Klemencic Associates (MKA)), several full-sized NLT/DLT floor will be tested to failure in the structural engineering laboratory at Colorado State University. Based on component level test results, 2 or 3 floors of NLT/DLT diaphragms will be incorporated into a (planned) full-scale 10-story full-scale mass timber building that will be tested on the world’s largest outdoor shake table for demonstration and education/outreach.
Project contact is Shiling Pei at the Colorado School of Mines
Summary
NHERI Tallwood project is an effort to develop and validate a resilient-based seismic design methodology for tall wood buildings. The project started in September 2016 and will last till 2020. The project team will validate the design methodology through shake table testing of a 10-story full-scaled wood building specimen at NHERI@UCSD. It will be the world's largest wood building tested at full-scale.
Project contact is Jianhui Zhou at the University of Northern British Columbia
Summary
The impact sound perceived in the lower volume in a building is radiated by the vibration of the ceiling transmitted from the vibration of the floor generated by an impact source in the upper volume. Thus, the dynamic behaviour of a floor is one crucial intermediate step to understand the impact sound insulation performance of such a floor. A key to reducing the impact sound is to isolate the structural floor from the subfloor. Floating floor construction is a common way of improving the impact sound insulation, which is to float a concrete topping on the mass timber floor with an elastic layer in between. There are two types of floating floor solutions, a) with a continuous elastic layer and b) with point bearing elastic mounts as shown in Figure 1. This study will investigate both solutions and will provide guidance on how to adopt both solutions for mass timber floors with an exposed ceiling.
The objectives of this project are:
1. To measure the sound insulation performance of mass timber floors with full-scale concrete topping on various continuous elastic interlayer materials
2. To measure the sound insulation performance of mass timber floors with full-scale concrete topping on discrete elastic load mounts
