The provisions to determine the deflection of gypsum wallboard (GWB) sheathed shearwalls available in the Canadian and American standards are limited to nailed shearwalls and are rudimentary compared to the wood based sheathing equations. There is currently no fastener slip model for the GWB sheathed shearwalls that are fastened with GWB screws. A main goal of this study is to improve the existing equations for nailed GWB sheathed shearwalls and develop a suitable analytical expression that can be used for GWB fastened with screws. In total, 270 GWB sheathed joints were subjected to reversed cyclic loading with variations including GWB type, thickness, fastener type, fastener size and manufacturers. The power model type is used to develop the fastener slip equations for nails and screws, which have GWB density and fastener diameter as equation inputs. The accuracy of the developed model is then validated by comparing the tested full-scale GWB sheathed shearwall deflection to the deflection calculated using the newly proposed fastener slip models. The proposed equation is a significant improvement to the existing code provisions. Component testing was performed on the fasteners (center point bending test) and the GWB (dowel bearing test). The results of these tests were used to determine the joint capacity based on the European Yield Model. It was also found that the shearwall capacity could be predicted by considering the joint level capacity while accounting for the number of joints at a panel edge. The joint level and full-scale experimental results are also validated with the use of an analysis program (SAPWood) to model the joint level hysteresis as a hysteretic spring with 10 model fitting parameters. The developed joint level hysteretic model was then used to represent the fasteners connecting the sheathing panels to the lumber framing in the construction of the full-scale shearwall model.

Light-frame wood construction is frequently used in the U.S. High wind events, such as hurricanes, may cause severe damage to these structures by breaking the roof envelope. This study focuses on computing reliability indices of roof sheathing panels exposed to high wind events while considering a time and spatially varying wind load. A procedure is developed that links probabilistic and dynamic finite element analysis codes. The results show that a few critical panels are most susceptible to damage, while most panels have significantly higher reliability indices than previous studies based on simplified analyses have shown. By setting a target reliability index, panel nail spacing can be adjusted to provide a more uniform level of safety over the entire roof.

The behavior of wood shear walls has been the focus of researchers and engineers for many years due to their availability in the North American construction landscape. A review of the established literature showed that most of the research have focused on the shear wall behavior as a whole with no investigation specifically targeting the individual components of its deflection. Also, little to no attention has been given to the investigation of the cumulative effects especially when the out-of-plane diaphragm stiffness is considered. The current study aims at investigating the effects of construction details variation on the behavior of the shear walls and evaluating whether the current deflection equation, as per wood design standard (CSA 2014) can adequately predict the overall wall stiffness. A total of 27 full-scale single-storey walls, with different construction details and aspect ratios, were tested under either static or monotonic (as both are the same) loading. The parameters that were varied in the testing were the stud size and spacing, nail diameter and spacing, sheathing panel type and thickness and hold-down anchoring system/type. For the two-storey walls, two different loading cases were considered, namely where the load was applied at the top or bottom storey only. The results showed that the strength and stiffness correlated almost directly to the inverse of the wall aspect ratio. There was no clear trend when considering the effect of the walls’ aspect ratios on ductility. Unexpectedly, walls with aspect ratios not permitted according to the wood design standard (4:1 and 6:1) followed similar strength and stiffness trends and had sufficient ductility ratios as those with smaller aspect ratios. This observation explains in part some of the discrepancies found between engineering calculations and behavior of actual building with light frame wood shear walls. Significant discrepancies were found when comparing the various deflection constituent with those estimated using the design expression. Adding more end studs and changing the size of the studs had no significant effect on the overall wall capacity and little effect on its stiffness. Reducing the stud spacing had, as expected, no effect on the wall capacity; however, the results showed that the bending stiffness was affected by the overall number of studs in the wall and not solely by the end studs. Shear walls sheathed with plywood panels exhibits slightly higher peak load and initial stiffness than those with OSB, which was mainly attributed to the greater panel thickness, and possibly density, of the plywood. Both sheathing types provided similar levels of ductility, as expected. Thicker sheathing increased the capacity and stiffness of the wall with no significant change observed in ductility ratio. The wall strength was significantly affected by the nail diameter and nail spacing, but no difference was observed when the nail edge/end distance was increased. The results also showed that discrete hold-down system behaved in a non-linear manner with a significantly greater initial stiffness than that assumed in design. The study also showed that having continuous hold-down connections has a positive effect on the capacity, stiffness and ductility of the wall when compared with discrete hold-downs. Having no hold-down adversely affects the wall capacity and stiffness, but did not affect the ductility of the wall. For the two-storey walls, the deflection estimated based on the cumulative effect assumption showed slight differences when compared with that observed in the experimental study. It was observed that the majority of the cumulative effect stems from the rigid body rotation due to deformation in the hold-down devices. A Computer shear wall model (through SAP2000) was developed using linear “frame” and “membrane” elements for the framing and sheathing members, respectively, whereas the sheathing to framing nails and hold-down were modeled using nonlinear springs. It was found that the model was capable of predicting the peak load, ultimate deflection and yield loads with reasonable accuracy, but overestimated the initial stiffness and ductility of the walls. In general, when the force-displacement curves were compared it was evident that the model was capable of predicting the wall behaviour with reasonable accuracy. When investigating the cumulative effects using the model, the results clearly showed that the assumption of cumulative effects due to rigid body rotation is valid for stacked shearwalls with no consideration for the floor diaphragm. The effect of the diaphragm on the behavior of the shear walls, in particular its out-of-plane rigidity was simulated by modeling the floors as beam. The out of plane stiffness of the shear walls was investigated for idealized (infinitely stiff or flexible) as well as “realistic”. The results showed reductions in the shearwall deflection in the magnitude of approximately 80% considering the out of plane rigidity of the diaphragm. It was also concluded that considering conservative estimates of out of plane stiffness might lead to a very significant reduction in deflection and that assuming the floor diaphragm to be infinitely rigid out of plan seems reasonable. For diaphragms supported on multiple panels further reduction in the deflection was observed. More work, particularly at the experimental level, is needed to verify the finding obtained in the numerical investigation related to the effect of out of plane diaphragm stiffness.

This dissertation presents work targeted to study the effects of diaphragm flexibility on the seismic performance of light frame wood structures (LFWS). The finite element approach is considered for modeling LFWS as it is more detailed and provides a way to explicitly incorporate individual structural elements and corresponding material properties. It is also suitable for capturing the detailed response of LFWS components and the structure as a whole. The finite element modeling methodology developed herein is in general based on the work done by the other finite element researchers in this area. However, no submodeling or substructuring of subassemblages is performed and instead a detailed model considering almost every connection in the shear walls and diaphragms is developed. The studs, plates, sills, blockings and joists are modeled using linear isotropic three dimensional frame elements. A linear orthotropic shell element incorporating both membrane and plate behavior is used for the sheathings. The connections are modeled using oriented springs with modified Stewart hysteresis spring stiffnesses. The oriented spring pair has been found to give a more accurate representation of the sheathing to framing connections in shear walls and diaphragms when compared to non-oriented or single springs typically used by most researchers in the past. Fifty six finite element models of LFWS are created using the developed methodology and eighty eight nonlinear response history analyses are performed using the Imperial Valley and Northridge ground motions. These eighty eight analyses encompass the parametric study on the house models with varying aspect ratios, diaphragm flexibility and lateral force resisting system. Torsionally irregular house models showed the largest range of variation in peak base shear of individual shear walls, when corresponding flexible and rigid diaphragm models are compared. It is also found that presence of an interior shear wall helps in reducing peak base shears in the boundary walls of torsionally irregular models. The interior walls presence was also found to reduce the flexibility of diaphragm. A few analyses also showed that the nail connections are the major source of in-plane flexibility compared to sheathings within a diaphragm, irrespective of the aspect ratio of the diaphragm. A major part of the dissertation focuses on the development of a new high performance nonlinear dynamic finite element analysis program which is also used to analyze all the LFWS finite element models presented in this study. The program is named WoodFrameSolver and is written on a mixed language platform Microsoft Visual Studio .NET using object-oriented C++, C and FORTRAN. This tool set is capable of performing basic structural analysis chores like static and dynamic analysis of 3D structures. It has a wide collection of linear, nonlinear and hysteretic elements commonly used in LFWS analysis. The advanced analysis features include static, nonlinear dynamic and incremental dynamic analysis. A unique aspect of the program lies in its capability of capturing elastic displacement participation (sensitivity) of spring, link, frame and solid elements in static analysis. The program's performance and accuracy are similar to that of SAP 2000 which is chosen as a benchmark for validating the results. The use of fast and efficient serial and parallel solver libraries obtained from INTEL has reduced the solution time for repetitive dynamic analysis. The utilization of the standard C++ template library for iterations, storage and access has further optimized the analysis process, especially when problems with a large number of degrees of freedom are encountered. / Ph. D.

Most of the research on high strain rate effects on wood since the 1950s has been on impact loading. Very limited work has been conducted on full-scale wood specimens under blast loading. In North America, the prevalence of these structures makes them susceptible to unintended blast effects. The question on how to retrofit and protect these structures against blast loads has still not been addressed adequately, and design provisions for new wood structures against blast are not comprehensive. Far-field explosion effects were simulated using the University of Ottawa shock tube. Twenty-five light-frame wood stud walls were tested dynamically. The research program aimed to determine the response of light-frame wood stud walls to blast loads that correspond to the heavy to blow-out damage levels. The results showed that, under idealized simply supported end conditions, the stud walls failed in flexure. Under heavier loads, ripping of sheathing commonly used in light-frame wood structures was observed, which caused premature failure of the assembly because the load was not fully distributed to the studs. The use of stiffer sheathing or reinforcing the sheathing provided a better load path and the wall was capable of reaching its full capacity. The effect of using realistic boundary connection details was investigated, and the results showed that typical connection detailing performed poorly under blast loads. Designed steel brackets connecting the studs to the rim-joist allowed for the studs to reach their full capacity. An analytical single degree-of-freedom model was generated using material properties obtained from static testing. The model was validated using the experimental results from the shock tube testing. Also, a catcher system consisting of welded-wire-mesh was incorporated into the wall system in order to diminish debris throw.

A inovação tecnológica é resultante de um processo social, movido por agentes e necessidades selecionadas. A tecnologia é um instrumento útil e dirigido por interessados que influenciam decisões sobre o processo produtivo. É importante compreender como ocorre este processo de inovação na indústria da construção civil sob este aspecto teórico. Raramente, a questão sobre a seletividade das inovações é esboçada por pesquisadores da área. Portanto, é necessário adotar uma visão sistêmica, delineando os agentes articuladores e as necessidades elencadas para efetivação das mudanças. Para aprofundar este tema, selecionou-se o caso da implementação do sistema wood frame no Brasil a partir do ano de 2010. No histórico geral do país, desde a segunda metade do século XX, a indústria da construção em madeira foi pouco disseminada e apresentou poucas inovações tecnológicas. Mas, em 2009, o setor madeireiro se mobilizou mediante a denominada Comissão Casa Inteligente para transformar e incrementar sua produção. Como resultado desta ação conjunta, em 2012, o sistema construtivo leve em madeira denominado wood frame foi introduzido no programa habitacional Minha Casa Minha Vida (PMCMV) financiado por agentes públicos. Para compreender esta mudança no cenário brasileiro, esta tese tem como objetivo analisar como ocorreu esta introdução do sistema inovador wood frame na produção de habitação no Brasil. Para isso, sob a visão sistêmica, esta pesquisa busca responder o que motivou esta transformação técnica, quais agentes participaram deste processo, como se articularam para promover o wood frame e quais resultados obtiveram. Esta análise contribui para demonstrar como as articulações entre setor produtivo, Estado e instituições de ensino e pesquisa podem ser eficazes para promover as mudanças técnicas no setor de construções. / Technological innovation is the result of a social process guided by agents and selected needs. Technology is an instrument directed by the interested who influence decisions about the production process. It is important to comprehend how this innovation process occurs in the civil construction industry with this point of view. The issue about the selectivity of innovations is rarely outlined by researchers in this area. Therefore, it is necessary to understand how the process of technological innovation occurs under a systemic vision, outlining its agents and their selected needs to implement the changes. On this basis, for this research was selected the case of implementation of wood light frame construction in Brazil in the year of 2010. In the history of Brazil, since mid-XX century, the wood construction industry wasnt very disseminated and have presented few technological transformations. However recently, since 2009, the timber sector has been mobilizing through a committee to transform and increase its production. As a result of this joint action, in 2012, the wood light frame construction was introduced in the social housing program entitled Minha Casa Minha Vida (MCMV) funded by public agents. To understand this change in the scenario of wood construction in Brazil, this thesis aims to analyze how the introduction of the innovative wood frame system occurred in the production of social housing. For this, this research analyzes what motivated this technological change, which agents participated on this process, how they articulated and what results they outcome. This analysis contributes to demonstrate how the articulations between productive sector, state and educational institutions can be effective in promoting technical changes in the construction sector

Since 2004 there have been multiple devastating tsunamis around the globe triggered by large magnitude earthquakes; with the most recent being the Tohoku, Japan tsunami in March 2011. These tsunamis have caused significant loss of life and damage to the coastal communities impacted by these powerful waves. The resulting devastation has raised awareness of the dangers of tsunamis and the Network for Earthquake Engineering Simulation (NEES) housesmash project (NEEShousesmash), was started to investigate several different areas of tsunami inundation. The work presented in the following two manuscripts was performed at the O.H. Hinsdale Wave Lab and Gene D. Knudson Wood Engineering Lab, which are located at Oregon State University. This work represents a small portion of the total NEEShousesmash project, and is focused on improving the knowledge and predictability of tsunami loading and structural performance. The first manuscript investigates tsunami wave impact on full scale light-frame wood walls, and compares the measured forces to calculated values using the linear momentum equation, previously evaluated by Cross (1967). The results show for each wave height tested a peak transient force followed by a sustained quasi-static force, with a ratio of transient force to quasi-static force of 2.2. The results also show that the linear momentum equation did an acceptable job of predicting the measured transient forces on the walls to within ±10%, and that increased wall flexibility, 2x4 vs. 2x6 dimensional lumber, resulted in lower measured transient forces when subjected to similar tsunami wave heights. These results are important for practical use because the linear momentum equation is a simple equation to use, that only requires a couple of site specific input variables. The second manuscript is a continuation of the work done in the wave lab for the first manuscript. These experiments provide a starting point for expanding the testing of the structural response and performance of larger scale structures subjected to tsunami wave loads. By simulating tsunami loading in a traditional structures laboratory, the inherent limits of testing structural performance in small scale tsunami laboratory facilities is removed. The results show that a light-frame wood shear wall, built to current standards, is susceptible to premature failures from concentrated impact loads at intermediate heights compared to the design strength at full height. It is also shown that the out-of-plane walls subjected to both elastic and inelastic loads behave like a one way slab with minimal load sharing between adjacent studs. The failures observed during the hydrodynamic wave testing of the nailed connection between the bottom plate and studs was successfully reproduced, and shows that current construction standards are not fully utilizing the available capacity of each stud when subjected to tsunami waves. The reinforcement of this connection with traditional metal brackets would help increase the capacity of the out-of-plane wall to resist tsunami wave loads. / Graduation date: 2012

A inovação tecnológica é resultante de um processo social, movido por agentes e necessidades selecionadas. A tecnologia é um instrumento útil e dirigido por interessados que influenciam decisões sobre o processo produtivo. É importante compreender como ocorre este processo de inovação na indústria da construção civil sob este aspecto teórico. Raramente, a questão sobre a seletividade das inovações é esboçada por pesquisadores da área. Portanto, é necessário adotar uma visão sistêmica, delineando os agentes articuladores e as necessidades elencadas para efetivação das mudanças. Para aprofundar este tema, selecionou-se o caso da implementação do sistema wood frame no Brasil a partir do ano de 2010. No histórico geral do país, desde a segunda metade do século XX, a indústria da construção em madeira foi pouco disseminada e apresentou poucas inovações tecnológicas. Mas, em 2009, o setor madeireiro se mobilizou mediante a denominada Comissão Casa Inteligente para transformar e incrementar sua produção. Como resultado desta ação conjunta, em 2012, o sistema construtivo leve em madeira denominado wood frame foi introduzido no programa habitacional Minha Casa Minha Vida (PMCMV) financiado por agentes públicos. Para compreender esta mudança no cenário brasileiro, esta tese tem como objetivo analisar como ocorreu esta introdução do sistema inovador wood frame na produção de habitação no Brasil. Para isso, sob a visão sistêmica, esta pesquisa busca responder o que motivou esta transformação técnica, quais agentes participaram deste processo, como se articularam para promover o wood frame e quais resultados obtiveram. Esta análise contribui para demonstrar como as articulações entre setor produtivo, Estado e instituições de ensino e pesquisa podem ser eficazes para promover as mudanças técnicas no setor de construções. / Technological innovation is the result of a social process guided by agents and selected needs. Technology is an instrument directed by the interested who influence decisions about the production process. It is important to comprehend how this innovation process occurs in the civil construction industry with this point of view. The issue about the selectivity of innovations is rarely outlined by researchers in this area. Therefore, it is necessary to understand how the process of technological innovation occurs under a systemic vision, outlining its agents and their selected needs to implement the changes. On this basis, for this research was selected the case of implementation of wood light frame construction in Brazil in the year of 2010. In the history of Brazil, since mid-XX century, the wood construction industry wasnt very disseminated and have presented few technological transformations. However recently, since 2009, the timber sector has been mobilizing through a committee to transform and increase its production. As a result of this joint action, in 2012, the wood light frame construction was introduced in the social housing program entitled Minha Casa Minha Vida (MCMV) funded by public agents. To understand this change in the scenario of wood construction in Brazil, this thesis aims to analyze how the introduction of the innovative wood frame system occurred in the production of social housing. For this, this research analyzes what motivated this technological change, which agents participated on this process, how they articulated and what results they outcome. This analysis contributes to demonstrate how the articulations between productive sector, state and educational institutions can be effective in promoting technical changes in the construction sector

Vid projektering av ytterväggar ställs höga krav på funktion och utformning. Ytterväggar har en mängd olika konstruktionslösningar beroende på stomsystem, fasadmaterial och andra förutsättningar. Uppdragsgivaren WSP, vill underlätta kvalitetssäkringen och minska tidsåtgången vid projektering med hjälp av framtagna typdetaljer. Typdetaljerna är utformade med hänsyn till aspekterna fuktsäkerhet, robusthet och kostnad. Intervjuer med konstruktörer, litteraturstudier samt kontakt med produktleverantörer, ligger till grund för arbetet. Utifrån analys av insamlat material har konstruktionslösningar tagits fram utifrån en maximal livslängd. Arbetet har resulterat i två typdetaljer för tung stomme och tre för lätt stomme, med fasadmaterialen puts, tegel samt skivmaterial. Tillhörande teknisk beskrivning, U-värde och kostnadsbild har tagits fram för vardera typdetalj. / Moisture saftey; Robustness; Cost; Exterior wall; Light frame; Heavy frame; Construction details   Abstract på engelska: Function and design have always been critically important when designing exterior walls. Several designs can be possible but are largely dependent upon the framework system, facade material as well as various other considerations. The client, WSP, wish to guarantee quality whilst reducing planning time but also maintaining factors such as moisture safety, robustness and cost. The basis of the work consisted of interviews with designers, revision of literature and product supplier liaison. Based upon analysis of collected material, the designs have been developed to ensure a maximum life span. The result has produced both heavy and light frame designs by utilising plaster, brick and sheet materials for the facade construction. The relevant technical descriptions, U-values and overall cost estimates have been developed for each construction details.

Deliberate and accidental explosions along with the heightened risk of loss of life and property damage during such events have highlighted the need for research in the behaviour of materials under high strain rates. Where an extensive body of research is available on steel and concrete structures, little to no details on how to address the design or retrofitting of wood structures subjected to a blast threat are available. Studies reported in the literature that focused on full scale light-frame wood structures did not quantify the increase in capacity due to the dynamic loading while the studies that did quantify the increase mostly stems from small clear specimens that are not representative of the behaviour of structural size members with defects. Tests on larger-scale specimens have mostly focused on the material properties and not the structural behaviour of subsystems. Advancements in design and construction techniques have greatly contributed to the emergence of taller and safer wood structures which increase potential for blast threat. This thesis presents results on the flexural behaviour of light-frame wood stud walls subjected to shock wave loading using the University of Ottawa shock tube. The emphasis is on the overall behaviour of the wall subsystem, especially the interaction between the sheathing and the studs through the nailed connection. The approach employed in this experimental program was holistic, where the specimens were investigated at the component and the subsystem levels. Twenty walls consisting of 38 mm x 140 mm machine stress-rated (MSR) studs spaced 406 mm on center and sheathed with two different types and sheathing thicknesses were tested to failure under static and dynamic loads. The experimental results were used to determine dynamic increase factors (DIFs) and a material predictive model was validated using experimental data. The implications of the code are also discussed and compared to the experimental data. Once validated, an equivalent single-degree-of-freedom (SDOF) model incorporating partial composite action was used to evaluate current analysis and design assumptions. The results showed that a shock tube can effectively be used to generate high strain-rate flexural response in wood members and that the material predictive model was found suitable to effectively predict the displacement resulting from shock wave loading. Furthermore, it was found that current analysis and design approaches overestimated the wall displacements.