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This paper focuses on the effect of the decay damage of the ancient timber building (ATB) with the one-way straight mortise-tenon (OWSMT) joints on the seismic performance of the wood frame (WF). The artificial damage simulation method was used to consider the varying degrees of damage to OWSMT joints considering the damage depth and surface damage...
The method for generating maximum amplitude and signal to noise ratio values by using second order high pass Butterworth filter on local seismic magnitude scale calculations is proposed. The test data are signals from local earthquake that have been occurred in Sunda Strait on April 8th 2012. Based on the experimental results, a 8 Hz cutoff frequen...
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... Drifts should ideally be kept below 0.4% where it is expected that more significant damage begins to manifest. Below this threshold, damage is expected to be superficial and easily repairable, while drifts below 0.1% are expected to result in no damage (Christovasilis et al. 2009). It is therefore the designer's prerogative to balance the performance parameters to achieve an acceptable level of structural and economic performance. ...
... The peak interstorey drift was effectively reduced from 0.75% to 0.22%. While this reduction did not achieve the threshold of 0.1%, at which point no damage is expected (Christovasilis et al. 2009), it did succeed in limiting drifts to levels where the interstorey drift causes only superficial and easily repairable damage. This represents a marked improvement when compared to the fixed base drifts, which were approaching a range consistent with moderate levels of damage. ...
In Canada, most single-family wood-frame residential structures in seismically hazardous regions are constructed according to Part 9 of Division B of the National Building Code (or similar provincial standards) using nonengineering methods. These structures are expected to perform well during an earthquake regarding life safety but may sustain severe economic losses. Seismic isolation is an emerging technology that provides excellent life safety and economic performance. While this technology has proven effective at protecting structures from earthquakes, no nonengineering methodologies exist that are compatible with Part 9 methods. This limitation produces significant testing, design, and cost barriers that restrict the application of base isolation on vulnerable Part 9 structures. To eliminate or reduce these cost barriers, a program framework was developed to perform the engineering seismic design and analysis for a base-isolated Part 9 single-family residential structure. The proposed methodology further encourages the application of seismic isolation to Part 9 structures.
... Subsequently, Taylor et al. [28] evaluated the seismic resistance of rainscreen stucco systems for BC residential wood construction by conducting 18 cyclic static tests on full-scale shearwalls with various stucco configurations. The NEESWood Project targeted to "safely increase the height of woodframe construction" by developing a direct displacement-based design philosophy [29]. A full-scale two-story woodframe townhouse with plan dimensions of 7 m by 17 m was tested on the E-Defense (Miki) shake table in Japan. ...
This paper presents fragility curves for conventional low-rise light-frame wood buildings in southwestern British Columbia, Canada, for long duration subduction earthquakes. Computational models of four representative two-story houses (two engineered and two non-engineered) are developed and validated using full-scale shake table testing data. Damage states are evaluated using the Park and Ang damage index. Incremental dynamic analyses are employed for calibrating and assessing the index. Duration effects are investigated by using 30 long duration subduction motions and 30 “spectrally equivalent” short duration crustal motions. The results indicate that the considered houses are more vulnerable to damage under subduction motions which increase the median damage indices of both individual shearwalls and entire lateral systems for all four houses at the same level of ground shaking. The correlation between system damage indices with ground motion duration was dependent on the level of ground shaking and the seismic resistance of the systems. The results further demonstrate that exterior stucco finish greatly reduces the seismic damage and can be used as an effective seismic retrofit strategy for conventional non-engineered wood construction.
... In order to validate this approach, the response of the structure under the three ground motions considered has been evaluated in terms of an equivalent single degree-of-freedom system as shown in Section 7.8 of [42]. For each ground motion, considering a single mode shape of the structure based on the maximum displacements obtained, the maximum base shear and the maximum roof displacement have been transformed in equivalent spectral acceleration and spectral displacement, as shown in Fig. 9, and are illustrated along with the 5%, 10% and 15% damped accelerationdisplacement spectra of the motions. ...
In the context of innovative seismic-resistant structures, Cross Laminated Timber (CLT) construction holds an important position at a global level, supported by important full-scale tests and studies of the non-linear behaviour of these structures for severe events, demonstrating excellent performance. The present study aims to transfer current knowledge in the form of modelling approaches applicable to design engineers presenting tools and methodologies pertinent to the daily procedures of professional practice, thus relating to linear static and dynamic analyses. Two different approaches of structural modelling are presented, validated and compared; one that is based on a distributed representation of the connections between the structural panels and a second that is based on a discrete representation. Both models are validated by comparing the time-history responses with the full-scale shake-table test results of a 3-storey CLT structure under three earthquakes, showing in both cases a reliable estimate of the structural response. Finally, a parametric study for the damping coefficient of the structural response is presented and the typical value of 5% is evaluated. It is shown that values greater than 5% can be more applicable in order to compensate for the influence of the friction developed primarily between wall and floor panels on the global energy dissipation capacity of the structure.
... Starting in the late 1980s, testing on full-scale wooden frame houses subjected to earthquake ground motions on a shake table were reported in Japan, Korea, and Greece (Carydis and Vougioukas 1989;Tanaka et al. 1998;Kohara and Miyazawa 1998;Ohashi et al. 1998;Yamaguchi and Minowa 1998;Seo et al. 1999). For single-family houses and two-story houses, full-scale shake table tests were conducted under the Consortium of Universities for Research in Earthquake Engineering (CUREE) project (Fischer et al. 2001;Schierle 2002;Filiatrault et al. 2002;Filiatrault 2001) and the NEESWood project (Filiatrault et al. 2010;Christovasilis et al. 2007). van de Lindt et al. ( , 2012 reported on the full-scale test on a six-story light frame building. ...
Immediately after the 2016 Kumamoto earthquake series, a detailed damage assessment of more than 2,500 wooden houses was conducted at Mashiki Town, Kumamoto. Severe structural and nonstructural components damages were observed for buildings designed after the 2000 building standard law. Results of the field investigation were used to identify vulnerable building type, and in October 2017, a full-scale, two-story, Japanese conventional post and beam wood townhouse was tested under the 2016 Kumamoto earthquake series recorded at the KiK-net station. A triaxial shake table testing facility located in Miki City, Japan, was used. The tested building survived the foreshock and mainshock of the Kumamoto earthquake, and the extent of damage reasonably agreed with the result of the survey around the KiK-net station. Results of the experimental tests will help designers and decision makers to understand the seismic response and damage of the test building and come up with mitigation alternatives.
... Other factors beyond hysteretic model parameters that can influence collapse performance evaluations include use of an alternative definition of the nonsimulated collapse interstory drift based on observations from testing (Christovasilis et al. 2007;Filiatrault et al. 2009;Pei et al. 2012); use of a 0% or near-0% damping assumption coupled with explicit modeling of all sources of energy dissipation, including but not limited to nonstructural wall finish materials; revised and/or additional index model designs to encompass a range of strength and stiffness variations story-bystory over the height of the structure; and inclusion of diaphragm hysteretic response in overall building response using 3D models. Additionally, revised and/or additional index models could be used to address (1) the potential for designer variation in specified shear wall sheathing and nailing to meet design requirements; (2) the potential for variation in specified shear wall type, such as perforated shear walls, shear walls designed for force transfer around openings, or a mixture of high-aspect-ratio and low-aspect-ratio full-height shear walls or combinations thereof; and (3) influence of finish materials such as gypsum wallboard and stucco on shear wall hysteretic response, because these materials have been shown through testing to improve seismic performance (Filiatrault et al. 2002). ...
This paper presents a numerical investigation of the influence of varying three parameters of the cyclic analysis of shear walls in wood-frame structures (CASHEW) 10-parameter wood-frame shear wall hysteretic model that have distinctly different effects on the shape of the backbone curve. The purpose is to assess the sensitivity of wood-frame shear wall collapse performance to changes from the baseline assumptions used to validate the FEMA P695 collapse performance methodology. The variations in backbone curve shape are intended to reflect observed variations in experimental response due to test methods, test boundary conditions, and shear wall aspect ratio. The paper also investigates the influence of including P-delta effects and the use of assumed equivalent viscous damping of 5% of critical. The baseline assumptions exclude P-delta effects and use 1% damping. A total of 126 unique analyses are conducted for six of the FEMA P695 wood-frame shear wall index models ranging from two to five stories. The results show that improved collapse performance (increased adjusted collapse margin ratio) occurs for hysteretic model assumptions that reduce (less negative) postpeak stiffness, increase displacement at peak strength, and increase peak strength intercept. These hysteretic model changes produce improved collapse performance for cases modeled with and without P-delta and for cases modeled with 1% and 5% damping. The inclusion of P-delta effects reduces adjusted collapse margin ratio by an average of 10% relative to the without-P-delta baseline. Use of 5% damping in these models improves adjusted collapse margin ratio by an average of 13% relative to the 1% damping baseline.
... This project started in 2006 with a full-scale seismic shake-table benchmark test of 2-story wood-frame townhouse building at the University at Buffalo, New York. Major findings from the first benchmark test of the structure have been described by Christovasilis et al. (2009), Filiatrault et al. (2008), and Filiatrault et al. (2010. The test building (with a footprint of 7 × 18.3 m) was tested at five different test phases for ordinary and strong near-field ground motions. ...
Wood-frame shear wall structures are commonly used for residential and nonresidential buildings. Extensive research has been performed on these structures to accurately model their behavior due to dynamic loads. Among the various system parameters that affect the response, damping has been identified as a complex energy-dissipation phenomenon that varies from the wood material level to the wood-frame shear wall and diaphragm assembly level to the full structural system level. Connections and nonstructural components and finishes also influence the damping characteristics. Although it is known from physical testing that damping behavior is highly nonlinear and dependent on the amplitude of deformation, it is almost universally represented mathematically with linear viscous models that are amplitude-independent. Given that the viscous damping model is not consistent with observed behavior, it is necessary to develop improved analytical models. A first step in developing such models is to review the available literature on the physical testing of wood-frame shear wall structures and learn how damping is manifested at all levels of the system hierarchy. To this end, a comprehensive review has been completed using literature available over the last several decades. The purpose of this paper is to provide a summary of the review, with the desired result that the paper can serve as a reference for the development of rational damping models and improved procedures for the analysis of wood-frame shear wall structures.
... Folz and Filiatrault [5] used experimental test results from the projects for an implementation and verification of a developed simple numerical model formulated in Folz and Filiatrault [6]. As a part of a NEESWood project, a full-scale shake table test of a two-story house (Christovasilis, Filiatrault and Wanitkorkul [7]) and a series of shake table tests on a six-storey light-frame wood building (van de Lindt, Pei and Pryor [8], van de Lindt et al. [9]) were conducted. In Europe, a fullscale shake table test on a three-storey timber-framed building sheathed with OSB boards (Piazza et al. [10]) and fibre-plaster boards (Piazza et al. [11]) was performed as a part of a SERIES project. ...
Behaviour of the timber-frame panel buildings under the horizontal forces is largely dependent on the type of the chosen design approach. The distribution of the horizontal forces along the timber-framed wall elements is thus influenced by the stiffness of the diaphragm, the stiffness of the wall elements and their connection with one another. However, there is a dilemma whether all the contributions that have an effect on the stiffness of the timber-framed walls are taken into account or not. The factors that influence the stiffness of the wall are the hold-down anchoring, the influence of the walls with openings and the timber-glass wall elements and the influence of the vertical loads. This paper numerically analyses the behaviour of the three-storey timber-frame panel building under the horizontal forces, using different design approaches. The basic approaches are upgraded by including different contributions to the stiffness of the timber-framed walls. Using different design approaches, a comparison of the horizontal force distribution among the walls, vibration periods and horizontal deformations of the building is being made. The results show that the design approach used has a great influence on the distribution of horizontal forces along the walls and the horizontal deformation of the building itself. Taking into account full-height timber-framed walls only, the horizontal deformations of the building could be underestimated.
... Furthermore, other sources of variability, such as wood species, moisture content, and nail type, are often neglected, and slight differences in the data introduce epistemic uncertainty, whereas load protocols followed during experimental tests can also result in data sets that are challenging to match/predict. An example of typical variability modeling wood shear walls is presented by considering the single fastener tests conducted by Christovasilis et al. (2009b) and summarized by Koliou (2014) and for 8d common and 10d common nails connected to 7=16-inch OSB with either 2 × 4 or 2 × 6 Hem-Fir framing (Table 3). The specimens used to develop the statistics of the hysteretic parameters of the CUREE model were nominally identical, yet the COV values were significant for some parameters and less significant for others. ...
Wood shear wall systems are the primary elements of seismic force-resisting system (SFRS) in virtually all light-frame wood buildings. Wood-frame buildings are unique because their nonstructural wall finishes, such as gypsum wallboard and stucco, provide significant strength and stiffness relative to that of the intended SFRS. Given the fact that nonstructural wall finishes can consist of multiple layered materials, it is essential to understand and characterize their behavior. The development of accurate and robust numerical models to capture the inelastic behavior of individual shear wall systems and buildings comprised of these wall systems is a critical step when performing nonlinear analyses for either design, evaluation, or upgrade of existing buildings using standards such as ASCE 41-13 [(ASCE 2013). ASCE 41-13: Seismic evaluation and retrofit of existing buildings]. In general, existing modeling approaches do not account for the implementation of residual strength and displacement, which have been observed for light-frame wood buildings during shake-table tests. Furthermore, nonlinear representation of elements in the ASCE 41 standard considers only cyclic envelopes to define the nonlinear response of wood shear wall systems and not full hysteretic properties. To address these challenges, this study was divided into three main parts. The first part focused on the development of an excessive synthesis of wall assembly tests incorporating different wood sheathing materials and material combinations, and the evaluation of their force-displacement response. The second part introduced a new envelope curve proposed for modeling wood-frame wall systems with the parameters of this curve identified for the different material combinations included in the synthesis of Step 1. Finally, the proposed backbone curve was implemented in a case study of a multifamily wood frame building subjected to seismic excitation. Incremental dynamic analyses were conducted considering both the proposed envelope curve and the ASCE 41 modeling recommendations, and the response of the building structure was evaluated for three different performance levels (immediate occupancy, life safety, and collapse prevention) through fragility analysis. The main objective of this study was to introduce a beneficial wall-system level modeling tool for nonlinear analysis of light-frame wood buildings as specified in codes and standards in the United States.
... With detailed damages observed and recorded, [34] the latest numerical models for the timber structures are capable to capture the degradation of strength and energy-absorbing capacity by measuring the damage indexes throughout an earthquake. For example, the Park-Ang damage index, [35] which combines the deformation-based cumulative indexes with the energy-based cumulative indexes, has been used to evaluate the damages in the wood frame systems (e.g., Liang et al [36] ). ...
As one key to the implementation of the performance-based design methodologies for wood structures, the performance objectives and their corresponding limit state criteria are usually correlated with the peak (maximum) interstory drift demands. This paper evaluates the inelastic drift demands including the peak drift and the residual drift for the prototype timber portal frame structural elements. Analytical 2D-framed model representative of the study-case were subjected to a suite of 50 pulse-type earthquake ground motions. In addition, an accumulated damage index is added to the inputs of the nonlinear analyses to account for the damage caused by the previous ground excitations. Larger accumulated damages lead to larger inelastic drifts. Strong correlation is revealed among the drift demands, the peak ground accelerations, and the variables characterizing the nonlinear system behavior. Finally, estimation formulas for the peak and residual drift demands are proposed and validated with the simulated results from nonlinear time-history analyses. Based on the presented formulas, the resilience ratio and the effective elastic drift are further derived to comprehend the nonlinear behavior of such timber made structures.
... The results showed that, for light-frame wood buildings typical of the 1980s to 1990s in California, only moderate damage resulted during a design-level earthquake, while significant and costly damage occurred during the maximum credible earthquake (MCE). The full building and results are available in the project report by Christovasilis et al. [8]. During the CUREE-Caltech wood-frame project, a three-story apartment building with a tuck under garage was tested by Mosalam and Mahin [9] in which they were able to confirm that these types of buildings are prone to torsional response and soft-story collapse. ...
Soft-story wood-frame buildings have been recognized as a disaster preparedness problem for decades. There are tens of thousands of these multi-family three- and four-story structures throughout California and other cities in the United States. The majority were constructed between 1920 and 1970, with many being prevalent in the San Francisco Bay Area in California. The NEES-Soft project was a five-university multi-industry effort that culminated in a series of full-scale soft-story wood-frame building tests to validate retrofit philosophies proposed by (1) the Federal Emergency Management Agency (FEMA) P-807 guidelines and (2) a performance-based seismic retrofit (PBSR) approach developed within the project. Four different retrofit designs were developed and validated at full-scale, each with specified performance objectives, which were typically not the same. This paper focuses on the retrofit design using cross laminated timber (CLT) rocking panels and presents the experimental results of the full-scale shake table test of a four-story 370 m² (4000 ft²) soft-story test building with that FEMA P-807 focused retrofit in place. The building was subjected to the 1989 Loma Prieta and 1992 Cape Mendocino ground motions scaled to 5% damped spectral accelerations ranging from 0.2 to 0.9 g.
