This paper presents the analysis of the structural and thermal behaviour of an timber-concrete prefabricated composite wall system, the Concrete Glulam Framed Panel (CGFP) which is a panel made of a concrete slab and a structural glulam frame. The research analyses the structural performance with quasi-static in-plane tests, focused on the in-plane strength and stiffness of individual panels, and the thermal behaviour of the system with steady state tests using an hot box apparatus. The results validate the efficacy of proposed system ensuring the resistance and the dissipative structural behaviour through the hierarchy response characterized by the wood frame, the braced reinforced concrete panel of the singular module and by the rocking effects of global system.
This report is prepared for Softwood Lumber Board (SLB) by the NHERI TallWood Project team in order to provide a brief and timely update on the progress and preliminary research findings from the NHERI TallWood Project. This report is focused on the full-scale shake table test of a two-story mass timber building conducted during the summer of 2017 at NHERI@UC San Diego outdoor shake table.
The shake table test described in this report was conducted during a three-month period from June to August 2017. As the research team is still working on processing and analyzing the data obtained from the experiments, this report only discusses preliminary findings in a qualitative manner. The research team is expected to produce additional reports and publications based on the test results in the near future.
International Journal of Design & Nature and Ecodynamics
Technological developments and social trends can create demand for new building functionalities, necessitating the adaptation of existing buildings. This paper presents the development of a modular building structural system that provides for the harmonization between the structural and functional lifespans of a building in order to achieve greater sustainability. The limitations of the existing prefabricated urban buildings with respect to their adaptability are contrasted with the proposed solution. The use of prefabricated engineered materials, such as cross laminated timber (CLT) and CLT-concrete composites, in conjunction with a modular system, reduces any climatic effects. The inherent advantages of incorporating detachable connections allows for the necessary structural adaptability, subsequently harmonizing and elongating the structural and functional lifespans. The resulting sustainable concept, when applied to residential buildings, could serve as a solution to address projections of future urban growth.
New Zealand Society for Earthquake Engineering Conference
April 27-29, 2017, Wellington, New Zealand
Pres-Lam is a post-tensioned rocking timber technology that has been developed over the last decade at the University of Canterbury. Pres-Lam overcomes a major challenge in timber construction, the development of a high strength moment connection, by tying mass timber elements together with high-strength steel post-tensioned tendons. In seismic areas, additional reinforcing can be added to the system increasing capacity as well as providing hysteretic damping. In 2010 Pres-Lam moved from laboratory testing to onsite implementation and has now been used in the construction of numerous building in New Zealand and around the world. This paper will present the lateral load design of the first Pres-Lam structure to be built in the United States: the Peavy Building at Oregon State University, Corvallis, Oregon. Peavy is a three-storey mass timber building within the College of Forestry. A glulam and CLT gravity structure support the timber-concrete-composite floor, which is made up of CLT panels spanning between glulam beams. The lateral load carrying capacity is provided in the two orthogonal directions by Pres-Lam walls fabricated from Cross Laminated Timber (CLT). The paper will present an overview of the design philosophy and the main motivations for the use of the Pres-Lam system, discuss the requirements for U.S. code compliance, and review the nonlinear time-history analysis of the Pres-Lam structure.
Project contact is Luca Sorelli at Université Laval
Hybrid wood-concrete structures are emerging in the multi-storey wood building market, as they provide effective solutions in terms of lightness, rigidity, vibration and fire resistance (Yeoh et al., 2010, Dagenais et al., 2016). This project aims to reduce the cost of these hybrid floors by reducing the time of construction by prefabrication technology with emphasis on use. In addition, the goal is to explore the use of Ultra High Performance Fiber Composite Concrete (UHPC) to reduce the thickness of the wood slab, and also the use of ductile connections to increase the reliability of the floor (Habel and Gauvreau). 2008, Zhang and Gauvreau 2014, Auclair-Cuerrier et al 2016a). Finally, the concrete slab improves the diaphragm behavior of the floor to seismic actions.
This paper describes numerical modelling to predict the fire resistance of engineered timber floor systems. The floor systems under investigation are timber composite floors (various timber joist and box floor cross sections), and timber-concrete composite floors. The paper describes 3D numerical modelling of the floor systems using finite element software, carried out as a sequential thermo-mechanical analysis. Experimental testing of these floor assemblies is also being undertaken to calibrate and validate the models, with a number of full scale tests to determine the failure mechanisms for each floor type and assess fire damage to the respective system components. The final outcome of this research will be simplified design methods for calculating the fire resistance of a wide range of engineered timber floor systems.
The objective of this research is to characterize concrete-insulation-MTP connection properties, develop structural design procedures for strength and deflection of MTP-concrete composite floors (may account for two-way action) and test MTP-concrete strip beam and full-size floor.
Project contact is Luca Sorelli at Université Laval
To minimize the built-in energy of the floor, we need to replace the current system with lighter solutions that retain the key features for robustness and maintenance, and are cost-effective and easy to build (Spadea et al., 2015). This project aims to explore innovative flooring solutions that make up a light wood load-bearing structure reinforced underneath by naturally occurring polymeric fibers (FRP) (Bencardino and Condello 2016), which work well in tension, and above an Ultra-Thin Ultra High Performance Concrete Slab (UHPC) that works exceptionally well in compression. Considering the application of very large floors in multi-storey buildings, the following key questions will be addressed: 1) what form should such a system have, 2) how will this be analyzed, and what mode of failure will be desirable? (3) what practical limitations would be imposed by constructability, (4) what would be the gain on economic cost and environmental impact from a life cycle analysis point of view, and (5) is possible to use biosourced epoxy for connections. The methodology consists of: (i) systems analysis and shape optimization using finite element numerical techniques, (ii) connection shear tests, and (iii) proof of concept on a beam prototype.
The objective of this research is to conduct acoustic testing of MTP-concrete floor systems with STS and notched timber connections, develop optimum construction details for various occupancy requirements and generate design guide that addresses various performance attributes, including structural, vibration, acoustics and possibly fire.
The wood engineering community has dedicated a significant amount of effort over the last decades to establish a reliable predictive model for the load-carrying capacity of timber connections under wood failure mechanisms. Test results from various sources (Foschi and Longworth 1975; Johnsson 2003; Quenneville and Mohammad 2000; Stahl et al. 2004; Zarnani and Quenneville 2012a) demonstrate that for multi-fastener connections, failure of wood can be the dominant mode.
In existing wood strength prediction models for parallel to grain failure in timber connections using dowel-type fasteners, different methods consider the minimum, maximum or the summation of the tensile and shear capacities of the failed wood block planes. This results in disagreements between the experimental values and the predictions. It is postulated that these methods are not appropriate since the stiffness in the wood blocks adjacent to the tensile and shear planes differs and this leads to uneven load distribution amongst the resisting planes (Johnsson 2004; Zarnani and Quenneville 2012a).
The present study focuses on the nailed connections. A closed-form analytical method to determine the load-carrying capacity of wood under parallel-to-grain loading in small dowel-type connections in timber products is thus proposed. The proposed stiffness-based model has already been verified in brittle and mixed failure modes of timber rivet connections (Zarnani and Quenneville 2013b).