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Structural Health Monitoring and Post-Occupancy Performance of Mass Timber Buildings

Timeline: 
2016 - 2019
Project Lead: Mariapaola Riggio
Abstract: TDI researchers measured a wide range of performance indicators of CLT, both within a controlled laboratory setting and within occupied buildings outfitted with sensors. The goals were to generate monitoring protocols, acquire benchmark data about the holistic performance of CLT buildings (which will ultimately help define performance standards for CLT systems) and to explore how monitoring might reduce market barriers for CLT.
 

Performance of a CLT Modular Building Utilizing Low Value Pine Lumber from Logs Harvested in Pacific NW Forest Restoration Programs

Timeline: 
2019 - 2021

Research Team: Mariapaola Riggio and Lech Muszynski

Abstract: The objective of this project is to design, build, deploy, instrument, monitor and publicize a demonstration modular unit made from cross-laminated timber (CLT) using low-grade Ponderosa pine (PP). The demonstration unit will highlight the viability of large-volume production of modular units that can be used in low- and mid-rise structures.

Testing of a Cross-Laminated Timber Pier-and-Spandrel Seismic Retrofit Solution for Unreinforced Masonry Buildings

Timeline: 
2018 – 2019

Project Lead: Andre R. Barbosa

Introduction: Over the past several decades, thousands of unreinforced masonry (URM) buildings were constructed in the United States (US), many in highly seismic regions, such as the Pacific Northwest and California. URM bearing walls perform well when compressed under gravity loads, however they are extremely weak when resisting lateral loads (e.g. earthquake loads). Because earthquake forces are bidirectional, URM walls experience both in-plane and out-of-plane loading. To combat the in-plane failure of URM walls, a cross-laminated timber (CLT) pier-and-spandrel seismic retrofit solution was developed and testing during this research project. CLT is an engineered wood product that consists of layers of laminated timber boards glued together, so that each layer is oriented perpendicular to the adjacent layer(s). CLT is an attractive building material because it is renewable, promotes fast installation, and possesses a high strength-to-weight ratio.

Framework Project - Splice Testing

Timeline: 
2016 - 2018

Research Team: Andre Barbosa, Arijit Sinha, Christopher Higgins, Rajendra Soti

Abstract: This testing project focuses on structural testing to generate data that can be used to support the performance-based design of the framework project to be built in Portland, Oregon, namely in support of facilitating the design of rocking CLT walls. Specifically, this phase of testing would be developed using panels manufactured by DR Johnson. The testing being addressed in this scope of work includes CLT crushing tests and CLT wall panel tests.

Mass Plywood Panels (MPP): Performance, Design, and Application

Timeline: 
2019 - 2021
Project Team: Fred Kamke, Arijit Sinha
Abstract: This project aims to achieve two primary tasks: (1) to fill in the gaps in terms of mechanical performance of MPP, and then to create a performance, design, and application guidline for industry, and (2) to characterize the hygrothermal performance of MPP and correlate climatice conditions to bond performance, mechanical performance, and manufacturing standards.

Mass Plywood (MPP) Concrete Composite Floor Systems

Timeline: 
2019 - 2021
Project Team: Andre Barbosa, Arijit Sinha
Abstract: In order to facilitate adoption of new mass timber products into practice, physical testing is required to understand and predict structural behavior. While extensive testing has been conducted at Oregon State on basic engineering properties of mass plywood panels (MPP) and MPP-to-MPP connections, there exists no experimental data on connections between MPP and other timber members (e.g. glulam) or on composite behavior of MPP with a concrete topping. Previous testing on CLT concrete-composite systems looked at different CLT-to-concrete connection systems, with HBV shear connectors-steel plates partially embedded in the timber with epoxy resin- as a strong candidate in terms of strength and stiffness performance. This project will focus on exploring the performance of MPP-concrete composite systems with HBV connectors.

Design, Construction, and Maintenance of Mass Timber Post-Tensioned Shear Walls

Timeline: 
2019 - 2021
Project Lead: Mariapaola Riggio
Abstract: Earthquake engineers are focusing on performance-based design solutions that minimize damage, downtime, and dollars spent on repairs by designing buildings that have no residual drift or “leaning” after an event. The development of timber post-tensioned (PT), self-centering rocking shear walls addresses this high-performance demand. The system works by inserting unbonded steel rods or tendons into timber elements that are prestressed to provide a compressive force on the timber, which will pull the structure back into place after a strong horizontal action. But, because these systems are less than fifteen years old with just four real-world applications, little information is known regarding best practices and optimal methods for engineering design, construction and/or tensioning procedures, and long-term maintenance considerations. This project intends to contribute knowledge by testing both cross-laminated timber (CLT) and mass plywood panel (MPP) walls through testing of anchorage detailing, investigating tensioning procedures for construction, determining the contributions of creep on prestress loss over time, and comparing all laboratory test data to monitoring data from three of the four buildings in which this technology has been implemented, one of which is George W. Peavy Hall at Oregon State University. This will be accomplished by testing small- and full-scale specimens in the A.A. “Red” Emmerson Advanced Wood Products Laboratory, and small-scale specimens in an environmental chamber.

Cross-Laminated Timber Fasteners Solutions for Tall Wood Buildings

Timeline: 
2016 - 2019
Project Lead: Arijit Sinha
Abstract: Constructing buildings with cross-laminated timber (CLT) requires development of novel panel attachment methods and mechanisms. Architects and engineers need to know the engineering strength properties of connected panels, especially in an earthquake-prone area. This project will improve knowledge of three types of wall panel connections: wall-to-floor, wall-to-wall, and wall-to- foundation. A common method of joining panels is to use metal-plate-connectors with screw fasteners. Testing will determine the strength properties of metal connectors applied with different types and sizes of screw fasteners. A novel fastening system will be developed. The strength and stiffness parameters established will be validated using full-scale shear wall tests. The data will be used to develop a modeling tool that engineers can use when designing multi-story buildings to be constructed with CLT panels.

Behavior of CLT Diaphragm Panel-to-Panel Connections with Self-tapping Screws

Timeline: 
2016 - 2019
Project Lead: Thomas Miller
Abstract: Understanding how roof and floor systems (commonly called diaphragms by structural engineers) that are built from Pacific Northwest-sourced cross-laminated timber (CLT) panels perform in earthquake-prone areas is a critically needed area of research. These building components are key to transferring lateral forces from wind and earthquakes into the shear walls and down to the foundation. The tests performed in this project will provide data on a commonly used approach to connecting CLT panels within a floor or roof and the performance of the overall system and the screw fasteners. Structural engineers will directly benefit through improved design guidance. A broader benefit will be increased confidence in the construction of taller wood buildings in communities at greater risk for earthquakes.