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Performance evaluation of retrofitting strategies for non-seismically designed RC buildings using steel braces

Varum, H.; Teixeira-Dias, F.; Marques, P.; Pinto, A.; Bhatti, A.
Fonte: Springer Verlag Publicador: Springer Verlag
Tipo: Artigo de Revista Científica
ENG
Relevância na Pesquisa
26.15%
Recent major earthquakes around the world have evidenced that research in earthquake engineering must be directed to the vulnerability assessment of existing constructions lacking appropriate seismic resisting characteristics. Their retrofit or replacement should be made in order to reduce vulnerability, and consequent risk, to currently accepted levels. In this work, the efficiency of ductile steel eccentrically-braced systems in the seismic retrofitting of existing reinforced concrete (RC) buildings is studied. The retrofit technique studied consists in a bracing system with an energy dissipation device, designed to dissipate energy by shear deformation. The numerical model was calibrated with cyclic test results on a full-scale structure. The models used for the RC frame and masonry represent their real behavior and influence in the global structural response. The steel bracing system was modeled with strut rigid elements. The model for the energy dissipater device reproduces rigorously the behavior of the shear-link observed in the cyclic tests, namely in terms of shear, drift and energy dissipation. With the calibrated numerical model, a series of non-linear dynamic analyses were performed, for different earthquake input motions...

An application of reliability-based robustness assessment of steel moment resisting frame structures under post-mainshock cascading events

Ribeiro, Filipe; Barbosa, André R.; Neves, Luís A.C.
Fonte: Universidade Nova de Lisboa Publicador: Universidade Nova de Lisboa
Tipo: Artigo de Revista Científica
Publicado em //2013 ENG
Relevância na Pesquisa
36.21%
The paper presented herein proposes a reliability-based framework for quantifying the structural robustness considering the occurrence of a major earthquake (mainshock) and subsequent cascading hazard events, such as aftershocks that are triggered by the mainshock. These events can significantly increase the probability of failure of buildings, especially for structures that are damaged during the mainshock. The application of the proposed framework is exemplified through three numerical case studies. The case studies correspond to three SAC steel moment frame buildings of 3-, 9-, and 20- stories, which were designed to pre-Northridge codes and standards. Twodimensional nonlinear finite element models of the buildings are developed using the Open System for Earthquake Engineering Simulation framework (OpenSees), using a finite-length plastic hinge beam model and a bilinear constitutive law with deterioration, and are subjected to multiple mainshock-aftershock seismic sequences. For the three buildings analyzed herein, it is shown that the structural reliability under a single seismic event can be significantly different from that under a sequence of seismic events. The reliability-based robustness indicator used shows that the structural robustness is influenced by the extent by which a structure can distribute damage.

Impacts of lateral code changes associated with the 2006 International Building Code and the 2008 California Building Code

Ratley, Desirée Page
Fonte: Massachusetts Institute of Technology Publicador: Massachusetts Institute of Technology
Tipo: Tese de Doutorado Formato: 96 leaves
ENG
Relevância na Pesquisa
26.08%
The 2008 California Building Code (CBC) will adopt the structural section of the 2006 International Building Code (IBC), which includes alterations to the procedure to determine earthquake design loading, and a drastic move to a complicated method to determine design wind pressures. The implementation of the revised 2006 International Building Code, and the subsequent California adoption of the structural section will have significant effects on the design and construction of structures not only in California, but also the rest of the country. Through a comparison of the design of a steel moment-resisting frame low-rise structure, it was determined that the new code will result in design values that differ from those resulting from the previous codes. In order to compare the relevant codes in different areas of the country, this thesis considers three design scenarios for the low-rise structure: seismic loading in Southern California to compare the 2001 CBC, the 2003 and the 2006 IBC, seismic loading in the Midwest to compare the 2003 IBC and the 2006 IBC, and wind loading in Northern California to compare the 2001 CBC and the 2006 IBC.; (cont.) In the first case, the change from the 2001 CBC to the 2003 IBC was an 8 percent increase in base shear...

Response of earthquake-resistant reinforced-concrete buildings to blast loading

Saatcioglu, M.; Ozbakkaloglu, T.; Naumoski, N.; Lloyd, A.
Fonte: Natl Research Council Canada Publicador: Natl Research Council Canada
Tipo: Artigo de Revista Científica
Publicado em //2009 EN
Relevância na Pesquisa
36.05%
Recent bomb attacks on buildings have raised awareness about the vulnerability of structures to blast effects. The resiliency of structures against blast-induced impulsive loads is affected by structural characteristics that are also important for seismic resistance. Deformability and continuity of structural elements, strength, stiffness, and stability of the structural framing system and resistance to progressive collapse are factors that play important roles on the survivability of buildings under both blast and seismic loads. The significance of these structural parameters on blast resistance of reinforced concrete buildings is assessed through structural analysis. Both local element performance and global structural response are considered while also assessing the progressive collapse potential. The buildings under investigation include 10-storey moment resisting frames with or without shear walls. The blast loads selected consist of different charge-weight and standoff distance combinations. The results are presented in terms of ductility and drift demands. They indicate improved performance of seismic-resistant buildings when subjected to blast loads, in terms of local column performance, overall structural response, and progressive collapse potential.; Murat Saatcioglu...

Seismic performance of reinforced concrete frames.

Kashyap, Jaya
Fonte: Universidade de Adelaide Publicador: Universidade de Adelaide
Tipo: Tese de Doutorado
Publicado em //2009
Relevância na Pesquisa
26.42%
Many intra-tectonic plate regions are considered to have low to moderate seismic risk. However, devastating earthquakes can occur in these regions and result in high consequences in terms of casualties and damage. Non-ductile detailing practice employed in these structures make them prone to potential damage and failure during an earthquake. Furthermore, the use of infill walls is a divisive issue as on positive side dual wall-frame systems have beneficial effects related to strength, stiffness, and ductility. However, if not designed properly infill wall can also lead to undesirable structural failures of complete wall frame system. Although, there has been significant amount of international research in this area, it is worth noting that very little research exists for Australian frames. This thesis presents the experimental and analytical research conducted at The University of Adelaide to gain some insight into the behaviour of typically detailed Australian reinforced concrete frames subjected to ground motions. The main objectives of this research were (1) to investigate the behaviour of non-seismically designed reinforced concrete frames under a 500-YRP earthquake; (2) to determine the different magnitudes of earthquake (YRP) that are likely to cause excessive drifts in or collapse of gravity-load-designed reinforced concrete frames and (3) to investigate the effect of infill walls on the moment-resisting frames subjected to seismic loads. The experimental program consisted of earthquake simulation tests on a 1/5 scale model of a 3-storey reinforced concrete frame and four ½-scale reinforced concrete brick infilled frame specimens subjected to quasi-static cyclic loading. The analytical study included static pushover and non-linear dynamic analyses of the 3-...

In-field simulated seismic testing of as-built and retrofitted unreinforced masonry partition walls of the William Weir house in Wellington

Derakhshan, H.; Dizhur, D.; Lumantarna, R.; Cuthbert, J.; Griffith, M.; Ingham, J.
Fonte: New Zealand Structural Engineering Society Publicador: New Zealand Structural Engineering Society
Tipo: Artigo de Revista Científica
Publicado em //2010 EN
Relevância na Pesquisa
25.96%
Unreinforced masonry (URM) partition walls of William Weir House in Wellington were subjected to out-of-plane forces to investigate the as-built wall characteristic behaviour. The lateral load resisting system of the 1932 reinforced concrete building was scheduled to undergo seismic strengthening, and due to the absence of reliable wall out-of-plane assessment data, consulting engineers adopted an experimental proof-testing approach. A team of student researchers from the University of Auckland tested four URM partition walls by subjecting the walls to out-of-plane uniform pressure applied by means of a system of airbags. The testing included two mid-storey and two top-storey URM partitions, which had developed prior minor structural cracks. The full-scale in-situ testing confirmed that the precracked partitions had sufficient strength to resist the current New Zealand seismic demand, and the experimental programme resulted in substantial financial benefits for the client as none of the walls were identified as demolition or strengthening candidates. In addition to the as-built out-of-plane tests, two tests were conducted on partition walls retrofitted using near surface- mounted (NSM) fibre-reinforced polymer (FRP) strips. The results of the as-built and the retrofitted wall testing are reported...

Seismic Performance of a 3D Full-scale High-ductile Steel-concrete Composite Moment-resisting Frame-Part II: Test Results and Analytical Validation

BRACONI Aurelio; BURSI Oreste S.; FABBROCINO Giovanni; SALVATORE Walter; TAUCER Fabio; TREMBLAY Robert
Fonte: JOHN WILEY & SONS LTD Publicador: JOHN WILEY & SONS LTD
Tipo: Articles in Journals Formato: CD-ROM
ENG
Relevância na Pesquisa
26.08%
This paper presents the results of a multi-level pseudo-dynamic seismic test program that was performed to assess the performance of a full-scale three-bay, two-storey steel¿concrete composite moment-resisting frame built with partially encased composite columns and partial-strength beam-to-column joints. The system was designed to develop a ductile response in the joint components of beam-to-column joints including flexural yielding of beam end plates and shear yielding of the column web panel zone. The ground motion producing the damageability limit state interstorey drift caused minor damage while the ultimate limit state ground motion level entailed column web panel yielding, connection yielding and plastic hinging at the column base connections. The earthquake level chosen to approach the collapse limit state induced more damage and was accompanied by further column web panel yielding, connection yielding and inelastic phenomena at column base connections without local buckling. During the final quasi-static cyclic test with stepwise increasing displacement¿amplitudes up to an interstorey drift angle of 4.6%, the behaviour was ductile although cracking of beam-to-end-plate welds was observed. Correlations with numerical simulations taking into account the inelastic cyclic response of beam-to-column and column base joints are also presented in the paper together. Inelastic static pushover and time history analysis.; JRC.G.5-European laboratory for structural assessment

Performance evaluation of retrofitting strategies for non-seismically designed RC buildings using steel braces

VARUM Humberto; TEIXEIRA-DIAS Filipe; MARQUES Paulo; PINTO VIEIRA Artur; QADIR-BHATTI Abdul
Fonte: SPRINGER Publicador: SPRINGER
Tipo: Articles in Journals Formato: Online
ENG
Relevância na Pesquisa
16.14%
Recent major earthquakes around the world have evidenced that research in earthquake engineering must be directed to the vulnerability assessment of existing constructions lacking appropriate seismic resisting characteristics. Their retrofit or replacement should be made in order to reduce vulnerability, and consequent risk, to currently accepted levels. In this work, the efficiency of ductile steel eccentrically-braced systems in the seismic retrofitting of existing reinforced concrete (RC) buildings is studied. The retrofit technique studied consists in a bracing system with an energy dissipation device, designed to dissipate energy by shear deformation. The numerical model was calibrated with cyclic test results on a full-scale structure. The models used for the RC frame and masonry represent their real behavior and influence in the global structural response. The steel bracing system was modeled with strut rigid elements. The model for the energy dissipater device reproduces rigorously the behavior of the shear-link observed in the cyclic tests, namely in terms of shear, drift and energy dissipation. With the calibrated numerical model, a series of non-linear dynamic analyses were performed, for different earthquake input motions...

Pseudodynamic Tests on a Full-Scale 3-Storey Precast Concrete Building: Global Response

NEGRO Paolo; BOURNAS DIONYSIOS; MOLINA RUIZ Francisco Javier
Fonte: ELSEVIER SCI LTD Publicador: ELSEVIER SCI LTD
Tipo: Articles in Journals Formato: Printed
ENG
Relevância na Pesquisa
16.14%
In the framework of the SAFECAST Project, a full-scale three-storey precast building was subjected to a series of pseudodynamic (PsD) tests in the European Laboratory for Structural Assessment (ELSA). The mock-up was constructed in such a way that four different structural configurations could be investigated experimentally. Therefore, the behaviour of various parameters like the types of mechanical connections (traditional as well as innovative) and the presence or absence of shear walls along with the framed structure were investigated. The first PsD tests were conducted on a dual frame-wall precast system, where two precast shear wall units were connected to the mock up. The first test structure sustained the maximum earthquake for which it had been designed with small horizontal deformations. In the second layout, the shear walls were disconnected from the structure, to test the building in its most typical configuration, namely with hinged beam-column connections by means of dowel bars (shear connectors). This configuration was quite flexible and suffered large deformations under the design level earthquake. An innovative connection system, embedded in the precast elements, was then activated to create emulative beam-column connections in the last two structural configurations. In particular...

Experimental assessment of a three storey full-scale precast structure. SAFECAST Project: Work Package 4, Technical Report

NEGRO Paolo; BOURNAS DIONYSIOS; MOLINA RUIZ Francisco Javier; VIACCOZ Bernard; MAGONETTE Georges; CAPERAN Philippe
Fonte: Publications Office of the European Union Publicador: Publications Office of the European Union
Tipo: EUR - Scientific and Technical Research Reports Formato: Online
ENG
Relevância na Pesquisa
16.14%
In the framework of the SAFECAST Project, a full-scale three-storey precast building was subjected to a series of pseudodynamic (PsD) tests in the European Laboratory for Structural Assessment (ELSA) at the Joint Research Centre of the European Commission. The mock-up was constructed in such a way that four different structural configurations could be investigated experimentally. Therefore, the behaviour of various parameters like the types of mechanical connections (traditional as well as innovative) and the presence or absence of shear walls along with the framed structure were investigated. The first PsD tests were conducted on a dual frame-wall precast system, where two precast shear wall units were connected to the mock up. The first test structure sustained the maximum earthquake for which it had been designed with small horizontal deformations. In the second layout, the shear walls were disconnected from the structure, to test the building in its most typical configuration, namely with hinged beam-column connections by means of dowel bars (shear connectors). This configuration was quite flexible and suffered large deformations under the design level earthquake. An innovative connection system, embedded in the precast elements...

The role of claddings in the seismic response of precast structures: the SAFECLADDING full-scale tests

NEGRO Paolo; LAMPERTI TORNAGHI MARCO
Fonte: European Association for Earthquake Engineering Publicador: European Association for Earthquake Engineering
Tipo: Contributions to Conferences Formato: CD-ROM
ENG
Relevância na Pesquisa
25.91%
The knowledge gained with different research projects, focused on seismic performance of precast reinforced-concrete buildings and during different earthquakes, permits to observe that the frame resisting systems, if designed for seismic actions, maintain their efficiency. On the contrary, the façade cladding and the connections between structure and panels, can meet with failure. These observations draw the attention to the need of further research on this field. The SAFECLADDING Project was started to tackle this issue with the aim to Improve Fastening Systems of Cladding Panels for Precast Buildings in Seismic Zones. It is a Research Project for SMEs associations, granted by EU FP7 which involves seven industrial partners: enterprises, European or national associations of precast concrete producers; four universities and the European Laboratory for Structural Assessment (ELSA). The SAFECLADDING Project analyses the ways to improve the performance of existing buildings, as well as the new ones. Three different Approaches can be followed to enhance the connections in frame-cladding system: Isostatic, Integrated, and Dissipative. The experiment, the mock-up and the test sequence were designed to assess the most common cladding systems using the same frame structure. The mock-up is a single-storey building made by six square columns...

SEISMIC ENGINEERING RESEARCH INFRASTRUCTURES FOR EUROPEAN SYNERGIES. Full-scale experimental validation of a dual eccentrically braced frame with removable links (DUAREM)

SABAU GABRIEL ALEXANDRU; POLJANSEK Martin; TAUCER Fabio; PEGON Pierre; MOLINA RUIZ Francisco Javier; TIRELLI Daniel; VIACCOZ BERNARD; STRATAN Aurel; DUBINA Dan; IOAN CHESOAN Adriana
Fonte: Publications Office of the European Union Publicador: Publications Office of the European Union
Tipo: EUR - Scientific and Technical Research Reports Formato: Online
ENG
Relevância na Pesquisa
16.21%
Conventional seismic design philosophy is based on dissipative structural response, which implicitly accepts structural damage under the design earthquake load thus leading to significant economic losses. Different strategies can be employed in order to reduce damage to structures under moderate to strong earthquakes such as base isolation and various implementations of active and semi-active structural control. Other strategies rely on supplemental damping conferred to the structure through various devices. These solutions require specialized knowledge at the design stage and during erection, careful maintenance and high initial cost. Another option constitutes a conventional design with replaceable dissipative members, easy to substitute even after strong earthquake, and thus reducing the repair costs. A system with removable dissipative elements has to fulfil two requirements to be efficient. Firstly, inelastic deformations should occur in removable elements only. Secondly, the damaged dissipative elements must be replaceable. Replacing the elements is more efficient if the structure does not have large permanent deformations. These two concepts were implemented in a dual structure, obtained by combining steel eccentrically braced frames (with removable bolted links) and moment resisting frames. The bolted links provide the energy dissipation capacity...

Dual-Steel Eccentrically Braced Frames with Bolted Links – Simulation of Safe Removal Process

IOAN CHESOAN Adriana; STRATAN Aurel; DUBINA Dan; TAUCER Fabio
Fonte: Technical University of Cluj-Napoca Publicador: Technical University of Cluj-Napoca
Tipo: Articles in periodicals and books Formato: Online
ENG
Relevância na Pesquisa
16.08%
Current seismic design philosophy is based on dissipative structural response, which implicitly accepts damage to the main structure and significant economic losses. Repair of the structure is often impeded by the permanent (residual) drifts of the structure. The proposed research aims at reducing the repair costs and downtime of a structure hit by an earthquake, and consequently more rational design approach in the context of sustainability. These objectives are to be attained through removable dissipative members and re-centring capability of the structure, concepts that are to be implemented in a dual structure, obtained by combining steel eccentrically braced frames with removable bolted links with moment resisting frames. The bolted links are intended to provide the energy dissipation capacity and to be easily replaceable, while the more flexible moment resisting frames would provide the necessary re-centring capability to the structure. The columns of the structure are to be realised from high strength steel, in order to keep these members in the elastic range even under strong seismic input. Practical solutions regarding order in which bolted links need to be replaced are proposed. In order that the link removal process to be a safe one...

Parameterized Seismic Reliability Assessment and Life-Cycle Analysis of Aging Highway Bridges

Ghosh, Jayadipta
Fonte: Universidade Rice Publicador: Universidade Rice
ENG
Relevância na Pesquisa
26.21%
The highway bridge infrastructure system within the United States is rapidly deteriorating and a significant percentage of these bridges are approaching the end of their useful service life. Deterioration mechanisms affect the load resisting capacity of critical structural components and render aging highway bridges more vulnerable to earthquakes compared to pristine structures. While past literature has traditionally neglected the simultaneous consideration of seismic and aging threats to highway bridges, a joint fragility assessment framework is needed to evaluate the impact of deterioration mechanisms on bridge vulnerability during earthquakes. This research aims to offer an efficient methodology for accurate estimation of the seismic fragility of aging highway bridges. In addition to aging, which is a predominant threat that affects lifetime seismic reliability, other stressors such as repeated seismic events or simultaneous presence of truck traffic are also incorporated in the seismic fragility analysis. The impact of deterioration mechanisms on bridge component responses are assessed for a range of exposure conditions following the nonlinear dynamic analysis of three-dimensional high-fidelity finite element aging bridge models. Subsequently...

Pre-test numerical simulations and experimental program on a dual eccentrically braced frame with replaceable links

STRATAN Aurel; IOAN CHESOAN Adriana; DUBINA Dan; D'ANIELLO Mario; LA MANNA AMBROSINO Giovanni; LANDOLFO Raffaele; TAUCER Fabio; POLJANSEK Martin
Fonte: Politecnico di Torino Publicador: Politecnico di Torino
Tipo: Contributions to Conferences Formato: Online
ENG
Relevância na Pesquisa
16.08%
The repair costs and downtime of a structure hit by an earthquake can be significantly reduced by adopting removable dissipative members and providing the structure with re-centring capability. These two concepts were implemented in a dual structure, obtained by combining steel eccentrically braced frames (with removable bolted links) and moment resisting frames. The bolted links provide the energy dissipation capacity and are easily replaceable, while the more flexible moment resisting frames provide the necessary re-centring capability. The solution will be validated by full-scale pseudo-dynamic test of a three-storey model of a steel structure with re-centring capability at the European Laboratory for Structural Assessment (ELSA) at the Joint Research Centre in Ispra within the framework of Transnational Access of the SERIES Project financed by the European Commission. The paper presents pre-test numerical simulations performed on a dual eccentrically braced frame with replaceable links. Both local performance of bolted links and overall system performance were investigated.; JRC.G.4-European laboratory for structural assessment

Three-Dimensional Nonlinear Analysis of Tall Irregular Steel Buildings Subject to Strong Ground Motion

Krishnan, Swaminathan
Fonte: California Institute of Technology Publicador: California Institute of Technology
Tipo: Report or Paper; PeerReviewed Formato: application/pdf
Publicado em 01/01/2003
Relevância na Pesquisa
16.16%
Strong ground motion from a nearby fault has frequency content in the same range as the natural frequencies of tall buildings. This may have serious repercussions and is the topic of this dissertation. Buildings are designed per building code standards. But, are the code provisions adequate? Strong motion from large earthquakes has been recorded only in recent times in the near-source region. Have the current codes used this information to update tall structure design guidelines? Considerable damage has been observed in tall buildings from the Northridge, Kobe, Turkey, and Taiwan earthquakes. How will tall buildings designed per the latest code regulations perform if they were to be shaken by any of these earthquakes? This thesis attempts to answer these questions. Tall buildings by their nature are computationally intensive to analyze. They consist of thousands of degrees of freedom and when subjected to strong ground motion from a nearby source, exhibit inelastic response. Modeling this inelastic response requires an iterative approach that is computationally expensive. Furthermore, a large class of buildings, classified as irregular, exhibits complex behavior that can be studied only when the structures are modeled in their entirety. To this end...

An Assessment to Benchmark the Seismic Performance of a Code-Conforming Reinforced-Concrete Moment-Frame Building

Haselton, Curt B.; Goulet, Christine A.; Mitrani-Reiser, Judith; Beck, James L.; Deierlein, Gregory G.; Porter, Keith A.; Stewart, Jonathan P.; Taciroglu, Ertugrul
Fonte: Pacific Earthquake Engineering Research Center Publicador: Pacific Earthquake Engineering Research Center
Tipo: Report or Paper; PeerReviewed Formato: application/pdf
Publicado em /08/2008
Relevância na Pesquisa
26.24%
This report describes a state-of-the-art performance-based earthquake engineering methodology that is used to assess the seismic performance of a four-story reinforced concrete (RC) office building that is generally representative of low-rise office buildings constructed in highly seismic regions of California. This “benchmark” building is considered to be located at a site in the Los Angeles basin, and it was designed with a ductile RC special moment-resisting frame as its seismic lateral system that was designed according to modern building codes and standards. The building’s performance is quantified in terms of structural behavior up to collapse, structural and nonstructural damage and associated repair costs, and the risk of fatalities and their associated economic costs. To account for different building configurations that may be designed in practice to meet requirements of building size and use, eight structural design alternatives are used in the performance assessments. Our performance assessments account for important sources of uncertainty in the ground motion hazard, the structural response, structural and nonstructural damage, repair costs, and life-safety risk. The ground motion hazard characterization employs a site-specific probabilistic seismic hazard analysis and the evaluation of controlling seismic sources (through disaggregation) at seven ground motion levels (encompassing return periods ranging from 7 to 2475 years). Innovative procedures for ground motion selection and scaling are used to develop acceleration time history suites corresponding to each of the seven ground motion levels. Structural modeling utilizes both “fiber” models and “plastic hinge” models. Structural modeling uncertainties are investigated through comparison of these two modeling approaches...

Long-Period Building Response to Earthquakes in the San Francisco Bay Area

Olsen, Anna H.; Aagaard, Brad T.; Heaton, Thomas H.
Fonte: Seismological Society of America Publicador: Seismological Society of America
Tipo: Article; PeerReviewed Formato: application/pdf
Publicado em /04/2008
Relevância na Pesquisa
16.16%
This article reports a study of modeled, long-period building responses to ground-motion simulations of earthquakes in the San Francisco Bay Area. The earthquakes include the 1989 magnitude 6.9 Loma Prieta earthquake, a magnitude 7.8 simulation of the 1906 San Francisco earthquake, and two hypothetical magnitude 7.8 northern San Andreas fault earthquakes with hypocenters north and south of San Francisco. We use the simulated ground motions to excite nonlinear models of 20-story, steel, welded moment-resisting frame (MRF) buildings. We consider MRF buildings designed with two different strengths and modeled with either ductile or brittle welds. Using peak interstory drift ratio (IDR) as a performance measure, the stiffer, higher strength building models outperform the equivalent more flexible, lower strength designs. The hypothetical magnitude 7.8 earthquake with hypocenter north of San Francisco produces the most severe ground motions. In this simulation, the responses of the more flexible, lower strength building model with brittle welds exceed an IDR of 2.5% (that is, threaten life safety) on 54% of the urban area, compared to 4.6% of the urban area for the stiffer, higher strength building with ductile welds. We also use the simulated ground motions to predict the maximum isolator displacement of base-isolated buildings with linear...

Timber frames as an earthquake resisting system in Portugal

Poletti, Elisa; Vasconcelos, Graça; Lourenço, Paulo B.
Fonte: Taylor & Francis Group Publicador: Taylor & Francis Group
Tipo: Parte de Livro
Publicado em //2015 ENG
Relevância na Pesquisa
66.26%
Timber frames are commonly adopted as a structural element in many countries with specific characteristics varying locally, in termsof geometry and materials.Their diffusion in Southern European countries is linked to their good seismic-resistant capacity, but only in the last decade interest has grown for this structural typology, and studies have been performed to better understand their behaviour. In this contribution, a brief state of the art on existing timber frame building typologies is presented, focusing on their seismic-resistant characteristics. Additionally, an overview of possible strengthening solutions, adopted both in practice, and tested experimentally are presented. Their performance when applied to walls and connections is also discussed.

Rocking shear wall foundations in regions of moderate seismicity

van der Merwe,J E; Wium,J A
Fonte: Journal of the South African Institution of Civil Engineering Publicador: Journal of the South African Institution of Civil Engineering
Tipo: Artigo de Revista Científica Formato: text/html
Publicado em 01/01/2013 EN
Relevância na Pesquisa
26.24%
This paper presents a study which investigates the feasibility of a concept to reduce the size of shear wall foundations for earthquake forces in regions of moderate seismicity. The approach is to allow rocking of the shear wall foundation and to include the contribution of a shear wall and reinforced concrete frame to assist as a lateral force-resisting system. A simplified multi degree-of-freedom model with non-linear material properties was used to investigate this lateral-force-resisting system subjected to base accelerations from recorded ground motions. An example building was studied with the shear wall foundation designed to resist 0%, 20%, 40%, 60%, 80% and 100% of the design overturning moment from the seismic event. Non-linear time-history analyses were performed with input from seven scaled ground-motion records. It is shown that the concept warrants more detailed studies and that a significantly reduced shear wall foundation size is possible without failure of the lateral force-resisting system.