In structural mechanics there are several occasions where a linearized formulation of the original nonlinear problem reduces considerably the computational effort for the response analysis. In a broader sense, a linearized formulation can be viewed as a first-order expansion of the dynamic equilibrium of the system about a `static¿ configuration; yet caution should be exercised when identifying the `correct¿ static configuration. This paper uses as a case study the rocking response of a rigid block stepping on viscoelastic supports, whose non-linear dynamics is the subject of the companion paper, and elaborates on the challenge of identifying the most appropriate static configuration around which a first-order expansion will produce the most dependable results in each regime of motion. For the regime when the heel of the block separates, a revised set of linearized equations is presented, which is an improvement to the unconservative equations published previously in the literature. The associated eigenvalues demonstrate that the characteristics of the foundation do not affect the rocking motion of the block once the heel separates.

Seismic response of free standing un-anchored objects is required to be studied in Nuclear Power Plants (NPPs) for their own integrity and potential interaction with the surrounding seismically qualified safety systems. Rocking response of a rigid body subject to seismic excitation is not very well covered in the nuclear standards except for an approximate method given in ASCE 43-05 where the design basis earthquake (DBE) response spectrum for the NPPs given in the United States Nuclear Regulatory Commission (USNRC) regulatory guide 1.60 (known as NBK spectrum developed by Newmark, Blume and Kapur (1973)) is considered as seismic input. This study evaluates existing seismic design criteria for unanchored objects that are vulnerable to rocking and overturning inside nuclear power plants. The original work of Newmark et al (1973) is revisited in order to obtain the NBK spectra at unusual damping (8.4% for example), required in order to follow the ASCE 43-05 method. Eight earthquake records are selected from Newmark et al (1973) with varying Peak Ground Accelerations (PGAs) representing strong to moderate ground motions. Rocking response of rigid bodies to various earthquakes is determined by three methods: 1. The ASCE 43-05 method utilizing the NBK spectrum, 2. The ASCE 43-05 method utilizing the response spectrum of the earthquake records, and 3. solving the equations of motion of a rigid body for the earthquake records. Rocking spectra by these three methods created for eight earthquake records are compared with one another. It is concluded that the ASCE 43-05 method provides inaccurate predictions of the response. Considering the significant level of effort required to implement the ASCE 43-05 method, its inherent contradictions, and its inconsistent conservatism in estimating the seismic demands on rocking objects, it is concluded that the results obtained by nonlinear time history analysis are more accurate, reliable and less time consuming than those by the ASCE 43-05 method. The use of nonlinear dynamic analysis is recommended to obtain the pure planar rocking response of unanchored objects in nuclear facilities. / Thesis / Master of Applied Science (MASc)

Conventional fixed base walls are typically characterized by yielding that results in permanent damage, residual drifts and costly losses due to the service shutdown for structural repairs. Controlled rocking masonry walls have been developed as a solution to prevent structural damage when seismic events take place. These systems purposely allow the wall to rock from its foundation and have an uplift at the base, thus replacing the typical yielding at the base of conventional fixed-base walls. Controlled rocking masonry walls have traditionally been controlled by using unbonded post-tensioning strands to provide the self-centering behaviour. Although post-tensioning has shown favourable results, its implementation is difficult in practical applications, and post-tensioning losses due to yielding of the strands at large deformations can reduce their self-centering ability. In order to overcome such issues, an alternative controlled rocking system for masonry walls was developed recently, which is designed to self-center through vertical gravity loads only, instead of the post-tensioning tendons. The rocking response of this alternative system is controlled by using energy dissipation devices, so the system is referred to as Energy Dissipation-Controlled Rocking Masonry Walls (ED-CRMWs). The vertical gravity loads are primarily transferred to the ED-CRMWs from the floor slab at each level. Therefore, the wall-slab interaction should be investigated in order to ensure a fully resilient system. In this regard, the current study identifies and categorizes the potential issues that are expected to occur due to the interaction between the wall rocking mechanism and the floor slab, and then investigates the most common of these issues using a parametric study. The parametric study focuses on the vertical incompatibility of displacements that a hollow- core slab suffers when its supporting walls uplift by different displacements during seismic events. Three different spans, four different cross-sections and two different alternatives of prestress configurations are considered in this study. The models were developed using ABAQUS 6.18 commercial software. The results show the cracking/yielding behaviour of the slabs and their displacement capacities at five different stages. The obtained results are promising for the usage of hollow-core slabs on ED-CRMWs or similar systems that require this interaction, as the range of displacement capacities can accommodate many of the vertical displacement incompatibilities expected in many potential situations. / Thesis / Master of Applied Science (MASc)

Steel flexural yielding arms can be an effective energy dissipation device for several seismic force resisting systems, including controlled rocking masonry walls. In controlled rocking masonry walls, uplift of the wall from the foundation is allowed in a way that can localize damage and minimize post-earthquake residual drifts. However, along with other modes of failure, sliding of the rocking walls can increase drifts and damage if not adequately addressed. Controlled rocking systems have different alternatives to prevent sliding, which include the use of additional mechanical components (e.g. metal stoppers) at the corners to resist lateral forces while allowing the wall rocking motion. However, these mechanical components hinder the constructability of the wall in some cases. The use of an energy dissipation device (i.e. steel flexural yielding arm) to also prevent the wall sliding mechanism has not been fully explored to date. The development of an easily replaceable energy dissipation device with the ability to simultaneously resist sliding demands is expected to maintain the overall performance of controlled rocking masonry walls, while also enhancing post-earthquake repairability. The objective of the current study is to experimentally investigate the effect of axial forces on the behaviour of steel flexural yielding arms under cyclic loading. In this respect, the study first presents a description of the experimental program, test setup, and instrumentation. Next, the experimental results of the tested specimens are discussed in terms of the effect of axial forces on the load, displacement, and energy dissipation capacities of the tested devices. Finally, new design equations that account for axial forces are proposed and verified against the experimental data along with a finite element model. Based on the results, recommendations are given for the further development of externally attached and replaceable flexural yielding arms for controlled rocking masonry walls. / Thesis / Master of Applied Science (MASc) / Controlled rocking masonry walls can be a cost-efficient alternative to traditional masonry shear walls because of their enhanced performance, specifically to reduce and localize structural damage induced by seismic loads. However, a controlled rocking wall requires additional energy dissipation devices or post-tensioning techniques to compliment the rocking wall to achieve the desired performance. This thesis explores and improves a type of energy dissipation device for controlled rocking masonry walls and aims to provide detailed design specifications for professional engineers. A design and considerations from previous studies are discussed, followed by the experimental validation, and finally new design equations are proposed for this type of reliable, flexural energy dissipation device.

Controlled Rocking Steel Braced Frames (CRSBFs) have been developed as a high-performance structural solution to resist seismic forces, due to their ability to minimize structural damage and self-centre the structure back to its original position after an earthquake. A CRSBF is intentionally allowed to uplift and rock on its foundation, which acts as the nonlinear mechanism for the system rather than member yielding and buckling. While the CRSBF is in the rocking phase, the response of the system is controlled by prestressing which anchors the frame to the foundation and energy dissipation devices which are engaged by uplift. Although CRSBFs have shown promising structural performance, an assessment of the overall effectiveness of this system must also consider the performance of nonstructural components which have a significant impact on the safety and economic performance of the system. The purpose of this thesis is to compare the performance of nonstructural components in buildings with CRSBFs to their performance in a conventional codified system such as a buckling restrained braced frame (BRBF), while also investigating which design parameters influence nonstructural component demands in CRSBFs. The responses of various types of nonstructural components, including anchored components, stocky unanchored components that slide, and slender unanchored components that rock, are determined using a cascading analysis approach where absolute floor accelerations generated from nonlinear time-history analyses of each structural system are used as input for computing the responses of nonstructural components. The results show that the trade-off of maintaining elastic behaviour of the CRSBF members is, in general, larger demands on nonstructural components compared to the BRBF system. The results also show that the stiffness of the frame and vibration of the frame in its elastic higher modes are the main influencers for nonstructural component demands in buildings with CRSBFs, while energy dissipation has a minimal impact. / Thesis / Master of Applied Science (MASc) / Controlled Rocking Steel Braced Frames (CRSBFs) have been proposed as a high-performance structural system that resists earthquake forces on buildings. This system has the ability to minimize damage to structural members and self-centre the building back to its original position after an earthquake, two characteristics that are typically not achieved by current conventional systems. However, an assessment of the CRSBF’s overall effectiveness cannot be limited to the consideration of only the structural skeleton, as the performance of nonstructural components (e.g. architectural elements, mechanical and electrical equipment, furnishings, and building contents) that are not part of the structural skeleton can have a significant impact on the safety and economic performance of earthquake resisting systems. This thesis compares the demands on nonstructural components in buildings with CRSBFs to their demands in a more conventional system during earthquake motions. The results show that the trade-off for avoiding damage to structural members in the CRSBFs is often higher demands on the nonstructural components.

No description available.

Bridge substructures are generally constructed using cast-in-place concrete and designed to undergo inelastic deformation in earthquake events. Although this construction approach has proven to be economical and provides adequate seismic performance through the formation of ductile plastic hinges, there are downsides relating to construction speed and quality, and post-earthquake repairability. This thesis explores two categories of Accelerated Bridge Construction (ABC) connection types, which use precast concrete instead of cast-in-place concrete to offer advantages including increased construction speed and quality. High Damage (HD) ABC connection types emulate the seismic behaviour of cast-in-place construction through the formation of ductile plastic hinges. Controlled Damage (CD) ABC connection types use unbonded post-tensioned precast connections to offer additional advantages including reduced residual drifts, limited and controlled damage and simple repair options. Novel buckling-restrained, fused mild steel energy dissipators suitable for use in CD connections are also developed and tested. These designs utilise 'dry' fabrication to simplify the fabrication process and minimise cost. Half-scale experimental testing is carried out to demonstrate both the assembly processes and behaviour under reversed cyclic uniaxial and biaxial loading representing an earthquake event. Following benchmark testing, repair strategies are applied to the CD connection types and the columns are tested again, representing a subsequent earthquake event. Good results are obtained from all cases with relatively straightforward construction and repair processes. With further developments and testing, the connection types proposed can provide competitive alternatives to conventional bridge pier design with regard to seismic performance and life cycle costs, with the additional benefits associated with precast construction.

Made available in DSpace on 2017-07-10T19:25:02Z (GMT). No. of bitstreams: 1 Priscila Ferri.pdf: 2540438 bytes, checksum: 0e96b497fd0903bba8d9e7c5a5161c00 (MD5) Previous issue date: 2006-07-07 / The objective of this work was to evaluate the efficiencies of protein extration for attainment of proteins leaf concentrate cassava (Manihot esculenta Crantz), using seven methods of extration cited by authors CEREDA & VILPOUX (2003), CHAVES (1987), TUPINAMBÁ & VIEIRA (1979) and FASUYI & ALETOR (2005). The experiment was carried through in the dependences of the State University of the West of the Paraná campus Cascavel, in the laboratory of Sanitation of the course of Agricultural Engineering. The cassava leves had been harvested in third part of the plant with age of 12 months in a property of the city of Cascavel. For the protein extration dehydrated leves had been used, with rude protein texts in dry base of 36.55 % and humidity of 11.27%. Methods 1 and 2 cited by CEREDA & VILPOUX (2003), method 5 cited by CHAVES (1987), method 6 cited by TUPINAMBÁ & VIEIRA (1979) and method 7 of FASUYI & ALETOR (2005) had been the ones that had gotten greaters proteins texts in the concentrates, above of 50%. The biggest incomes of extration had been gotten by methods 2, 5, 6 and 7 with incomes of protein extration above of 35%. Methods 1, 2, 4 and 5 had been tested using two consecutive extrations similar to improve the losses of mass and to increase the extration income, however only occurred the reduction of the losses of mass in the process, not being then necessary the use of two phases of extration. Methods 1, 2, 4 and 5 had been compared, already applied with leves dehydrated, using cool leves. The cassava leves (Manihot esculenta Crantz) cool had been harvested in third part of the plant with age of 9 months with rude protein texts in dry base of 27.70% with 72% of humidity. It did not have difference in the extration incomes, being more advantageous to use dehydrated leves due to possess minors toxic factors and greater durability. Methods 2 and 5 had revealed alternative for attainment of cassava proteins leaf concentrates, due to extration easiness, and not to need equipment and materials that can increase the cost of protein extration, thus making possible one better exploitation of cassava leves. / O objetivo deste trabalho foi avaliar as eficiências de extração de proteínas para obtenção de concentrados protéicos de folhas de mandioca (Manihot esculenta Crantz), utilizando sete métodos de extração descritos por: CEREDA e VILPOUX (2003), CHAVES (1987), TUPINAMBÁ e VIEIRA (1979) e FASUYI e ALETOR (2005). O experimento foi realizado nas dependências da Universidade Estadual do Oeste do Paraná, campus de Cascavel, no Laboratório de Saneamento do curso de Engenharia Agrícola. As folhas de mandioca foram colhidas no terço superior da planta com idade de 12 meses em uma propriedade da cidade de Cascavel. Para a extração de proteínas utilizaram-se folhas desidratadas, com teores de proteína bruta em base seca de 36,55 % e umidade de 11,27%. Os métodos 1 e 2 descritos por CEREDA e VILPOUX (2003), o Método 5 descrito por CHAVES (1987), o Método 6 e descrito por TUPINAMBÁ e VIEIRA (1979) e o Método 7 descritos por FASUYI e ALETOR (2005) foram os que obtiveram maiores teores protéicos nos concentrados, acima de 50%. Os maiores rendimentos de extração foram obtidos pelos métodos 2 e 4, com rendimentos de extração de proteína acima de 35%. Foram testados os métodos 1, 2, 4 e 5, utilizando-se duas extrações consecutivas, a fim de melhorar as perdas de massa e aumentar o rendimento de extração, no entanto somente ocorreu a minimização das perdas de massa no processo, não sendo necessária a utilização de duas fases de extração. Foram comparados os métodos 1, 2, 4 e 5, já aplicados com folhas desidratadas, utilizando-se folhas frescas. As folhas de mandioca (Manihot esculenta Crantz) frescas foram colhidas no terço superior da planta com idade de 9 meses com teores de proteína bruta em base seca de 27,70% com 72% de umidade. Não houve diferença nos rendimentos de extração, sendo mais vantajoso utilizar folhas desidratadas, devido ao menor fator tóxico e maior durabilidade. Os métodos 2 e 5 mostraram-se alternativos para obtenção de concentrados protéicos de folhas de mandioca, devido à facilidade de extração e de não necessitarem de equipamentos e materiais que possam aumentar o custo de extração de proteínas, possibilitando assim um melhor reaproveitamento das folhas de mandioca.

Made available in DSpace on 2017-05-12T14:48:23Z (GMT). No. of bitstreams: 1 Priscila Ferri.pdf: 2540438 bytes, checksum: 0e96b497fd0903bba8d9e7c5a5161c00 (MD5) Previous issue date: 2006-07-07 / The objective of this work was to evaluate the efficiencies of protein extration for attainment of proteins leaf concentrate cassava (Manihot esculenta Crantz), using seven methods of extration cited by authors CEREDA & VILPOUX (2003), CHAVES (1987), TUPINAMBÁ & VIEIRA (1979) and FASUYI & ALETOR (2005). The experiment was carried through in the dependences of the State University of the West of the Paraná campus Cascavel, in the laboratory of Sanitation of the course of Agricultural Engineering. The cassava leves had been harvested in third part of the plant with age of 12 months in a property of the city of Cascavel. For the protein extration dehydrated leves had been used, with rude protein texts in dry base of 36.55 % and humidity of 11.27%. Methods 1 and 2 cited by CEREDA & VILPOUX (2003), method 5 cited by CHAVES (1987), method 6 cited by TUPINAMBÁ & VIEIRA (1979) and method 7 of FASUYI & ALETOR (2005) had been the ones that had gotten greaters proteins texts in the concentrates, above of 50%. The biggest incomes of extration had been gotten by methods 2, 5, 6 and 7 with incomes of protein extration above of 35%. Methods 1, 2, 4 and 5 had been tested using two consecutive extrations similar to improve the losses of mass and to increase the extration income, however only occurred the reduction of the losses of mass in the process, not being then necessary the use of two phases of extration. Methods 1, 2, 4 and 5 had been compared, already applied with leves dehydrated, using cool leves. The cassava leves (Manihot esculenta Crantz) cool had been harvested in third part of the plant with age of 9 months with rude protein texts in dry base of 27.70% with 72% of humidity. It did not have difference in the extration incomes, being more advantageous to use dehydrated leves due to possess minors toxic factors and greater durability. Methods 2 and 5 had revealed alternative for attainment of cassava proteins leaf concentrates, due to extration easiness, and not to need equipment and materials that can increase the cost of protein extration, thus making possible one better exploitation of cassava leves. / O objetivo deste trabalho foi avaliar as eficiências de extração de proteínas para obtenção de concentrados protéicos de folhas de mandioca (Manihot esculenta Crantz), utilizando sete métodos de extração descritos por: CEREDA e VILPOUX (2003), CHAVES (1987), TUPINAMBÁ e VIEIRA (1979) e FASUYI e ALETOR (2005). O experimento foi realizado nas dependências da Universidade Estadual do Oeste do Paraná, campus de Cascavel, no Laboratório de Saneamento do curso de Engenharia Agrícola. As folhas de mandioca foram colhidas no terço superior da planta com idade de 12 meses em uma propriedade da cidade de Cascavel. Para a extração de proteínas utilizaram-se folhas desidratadas, com teores de proteína bruta em base seca de 36,55 % e umidade de 11,27%. Os métodos 1 e 2 descritos por CEREDA e VILPOUX (2003), o Método 5 descrito por CHAVES (1987), o Método 6 e descrito por TUPINAMBÁ e VIEIRA (1979) e o Método 7 descritos por FASUYI e ALETOR (2005) foram os que obtiveram maiores teores protéicos nos concentrados, acima de 50%. Os maiores rendimentos de extração foram obtidos pelos métodos 2 e 4, com rendimentos de extração de proteína acima de 35%. Foram testados os métodos 1, 2, 4 e 5, utilizando-se duas extrações consecutivas, a fim de melhorar as perdas de massa e aumentar o rendimento de extração, no entanto somente ocorreu a minimização das perdas de massa no processo, não sendo necessária a utilização de duas fases de extração. Foram comparados os métodos 1, 2, 4 e 5, já aplicados com folhas desidratadas, utilizando-se folhas frescas. As folhas de mandioca (Manihot esculenta Crantz) frescas foram colhidas no terço superior da planta com idade de 9 meses com teores de proteína bruta em base seca de 27,70% com 72% de umidade. Não houve diferença nos rendimentos de extração, sendo mais vantajoso utilizar folhas desidratadas, devido ao menor fator tóxico e maior durabilidade. Os métodos 2 e 5 mostraram-se alternativos para obtenção de concentrados protéicos de folhas de mandioca, devido à facilidade de extração e de não necessitarem de equipamentos e materiais que possam aumentar o custo de extração de proteínas, possibilitando assim um melhor reaproveitamento das folhas de mandioca.

The controlled rocking heavy timber wall (CRHTW) is a high-performance structural solution that was first developed in New Zealand, mainly considering Laminated Veneer Lumber (LVL), to resist high seismic loads without sustaining structural damage. The wall responds in bending and shear to small lateral loads, and it rocks on its foundation in response to large seismic loads. In previous studies, rocking has been controlled by both energy dissipation elements and post-tensioning, and the latter returns the wall to its original position after a seismic event. The controlled rocking response avoids the need for structural repair after an earthquake, allowing for more rapid return to occupancy than in conventional structures. Whereas controlled rocking walls with supplemental energy dissipation have been studied before using LVL, this thesis proposes an adapted CRHTW in which the design and construction cost and complexity are reduced for low-to-moderate seismic hazard regions by removing supplemental energy dissipation and using cross-laminated timber (CLT) because of its positive economic and environmental potential in the North American market. Moreover, whereas previous research has focussed on direct displacement-based design procedures for CRHTWs, with limited consideration of force-based design parameters, this thesis focusses on force-based design procedures that are more common in practice. A design and analysis process is outlined for the adapted CRHTW, based on a similar methodology for controlled rocking steel braced frames. The design process includes a new proposal to minimize the design forces while still controlling peak drifts, and it also includes a new proposal for predicting the influence of the higher modes by referring to previous research on the capacity design of controlled rocking steel braced frames. Also, a numerical model is outlined, including both a baseline version and a lower-bound model based on comparison to experimental data. The numerical model is used for non-linear time-history analysis of a prototype design, confirming the expected performance of the adapted CRHTW, and the model is also used for incremental dynamic analyses of three-, six-, and nine-storey prototypes, which show a low probability of collapse. / Thesis / Master of Applied Science (MASc) / The controlled rocking heavy timber wall (CRHTW) is a high-performance structural solution that was developed to resist high seismic loads without sustaining structural damage. The wall responds in bending and shear to small lateral loads, and it rocks on its foundation in response to large seismic loads. In previous studies, rocking has been controlled by both energy dissipation elements and post-tensioning; the latter returns the wall to its original position after a seismic event. This controlled rocking behaviour mitigates structural damage and costly repairs. This thesis explores the value of an adapted CRHTW in which the design and construction costs and complexity are reduced for low-to-moderate seismic hazard regions by using post-tensioning but no supplemental energy dissipation. A design and analysis process is outlined; numerical analysis confirms the expected performance of the adapted CRHTW; and the system is shown to have a low probability of collapse.