- Revision of IAEE Guidelines for Earthquake Resistant Non-Engineered Construction
- A.S. Arya ; T. Boen ; Y. Ishiyama
- Book Title / Journal: Proceedings of the 15th World Conference on Earthquake Engineering, Lisbon, Portugal
- Year: 2012 , Volume: , Series:
- Earthquake engineering
- Keywords: non-engineered construction ; masonry
- Description
- A large majority of houses and buildings in the world can be classified as non-engineered construction, e.g. (1) un-reinforced masonry, (2) confined masonry, (3) wooden construction, (4) earthen construction (adobe or tapial). Most of the loss of life in past earthquakes has occurred due to the collapse of these houses and buildings. Because of the continued use of such construction, it is essential to introduce earthquake resistant features in their construction. The International Association for Earthquake Engineering (IAEE) published the “Guidelines for Earthquake Resistant Non-Engineered Construction” in 1986. More than twenty years have passed since the publication and the guidelines are still used in many parts in the world, the revision of the guidelines was discussed among three of the committee members for the 1986 edition. The revision is going to be completed with the supports of UNESCO and the International Institute of Seismology and Earthquake Engineering (IISEE), JAPAN.
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- Benefits of Vertically Distributed Isolation Devices for an 8-storey Structure with Complex Geometry
- T.J. Sullivan ; A. Lago ; G.M. Calvi
- Book Title / Journal: Proceedings of the 15th World Conference on Earthquake Engineering, Lisbon, Portugal
- Year: 2012 , Volume: , Series:
- Earthquake engineering
- Keywords: complex geometry ; diagrid ; displacement based design ; visco-elastic damper
- Description
- The construction of structures with curved or irregular geometry is becoming increasingly common as modern architects strive to create iconic buildings. However, the realization of complex building forms creates significant challenges in regions of high seismicity, since this introduces significant uncertainties in the likely plastic mechanism, with questions on the likely performance of connections and doubts about the probable loadpaths. This paper examines the benefits of a novel seismic design strategy that uses isolation devices distributed vertically up a building between the exterior structure (of complex-geometry) and the heavy internal core. An innovative Direct DBD methodology is used to design an 8-storey case study building in which viscoelastic devices are used. Non-linear time-history (NLTH) analyses are then conducted on a 3-dimensional model of the building and the results indicate that the target displacement and drifts for both the internal and external structures are well controlled by the design solution.
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- Modeling of Sliding Shear Resistance of Reinforced Masonry Squat Walls
- J. Centeno ; C.E. Ventura ; S. Brzev
- Book Title / Journal: Proceedings of the 15th World Conference on Earthquake Engineering, Lisbon, Portugal
- Year: 2012 , Volume: , Series:
- Earthquake engineering
- Keywords: reinforced masonry ; sliding shear mechanism ; Seismic response
- Description
- This paper presents the results of an ongoing research study on the sliding shear mechanism in reinforced masonry (RM) shear walls. An overview is presented of the current design procedure and its limitations. Findings of previous studies have been used to develop an analytical model that will allow to simulate the sliding shear response of RM shear walls subjected to earthquake ground shaking in a realistic manner, comparable with the results of experimental studies. The proposed analytical model is described in this paper, and the preliminary results are compared with the results of relevant experimental studies.
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- Towards a Direct Displacement-Based Loss Assessment Methodology for RC Frame Buildings
- D.P. Welch ; T.J. Sullivan ; G.M. Calvi
- Book Title / Journal: Proceedings of the 15th World Conference on Earthquake Engineering, Lisbon, Portugal
- Year: 2012 , Volume: , Series:
- Earthquake engineering
- Keywords: displacement-based assessment ; simplified direct loss estimation ; RC frames
- Description
- Various loss assessment methodologies have been proposed and developed over the past few decades to provide risk assessment on a regional scale. There is an increasing need, however, to provide engineers with practical tools for building-specific loss assessment. Recently, progress has been made towards probabilistic building-specific loss models such as the PEER PBEE framework. However, as some consider that comprehensive probabilistic methodologies could be too complex for most practicing engineers, this paper presents a simplified probabilistic loss assessment methodology that builds on a direct displacement-based assessment framework. The simplified methodology attempts to incorporate critical aspects of comprehensive loss assessment models while maintaining a computational onus suitable for the design office. The trial methodology is tested via examination of a 4-storey RC frame building and encouragingly, the direct losses estimated by the new approach are found to be similar to those estimated by the PEER methodology.
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- Characteristics Affecting the Vulnerability of Soft Storey Mechanisms
- H.A. Beigi ; T.J. Sullivan ; G.M. Calvi ; C. Christopoulos
- Book Title / Journal: Proceedings of the 15th World Conference on Earthquake Engineering, Lisbon, Portugal
- Year: 2012 , Volume: , Series:
- Earthquake engineering
- Keywords: soft-storey ; post-yield stiffness ; concrete frame retrofit
- Description
- The seismic vulnerability of a six storey RC frame building typical of Italian construction practice from the 1970’s is examined in this work, initially considering two different infill configurations; the first considers full masonry infill and the second considers an open ground storey with full masonry infill above the first floor. Results of incremental dynamic analyses indicate that structures with uniform infill are less likely to collapse. However, it is also recognized that the need to retrofit structures with partial infill should depend on the seismic hazard and acceptable risk. Therefore, to provide insight into the factors affecting the vulnerability of such RC frame structures, the impact of P-Delta effects, post-yield stiffness ratio and ground storey column characteristics are investigated. Results are discussed and because p-delta effects and column axial load ratios are found to affect the vulnerability significantly, an innovative retrofit strategy that considers these characteristics is proposed.
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- Nonlinear Response-History Analysis of Triple Friction Pendulum Bearings (TFPB), Installed Between stories Pendulum Bearings (TFPB), Installed Between Stories
- F. Hamidreza ; G.A. Gholamreza
- Book Title / Journal: Proceedings of the 15th World Conference on Earthquake Engineering, Lisbon, Portugal
- Year: 2012 , Volume: , Series:
- Earthquake engineering
- Keywords: Triple Friction Pendulum Bearing ; inter-story isolation system ; multi-story isolation system
- Description
- In recent years, the damage to the well-designed structures, caused by earthquake, has attracted the attention of engineers to use adaptive seismic isolation systems such as Triple Friction Pendulum Bearings (TFPBs). An adaptive seismic isolator can exhibit different stiffness and damping during its course of motion and consequently award appropriate performance in different hazard levels. This paper investigates application of TFPBs in six stories steel frame structure, while TFPBs is installed at different levels; such as base, first story, third story or combination of them, and each state is compared with fixed-base and base isolated structure. The results indicate that base and first story isolation systems are extremely effective in reduction of maximum drift ratio and story shear force however this effect is diminished by increasing level of isolators. Additionally providing a second isolation level to base isolated structure, leads to a significant reduction in base deformation which is an adequate technique in presence of near-fault ground motion.
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- Analytically Derived Fragility Curves for Unreinforced Masonry Buildings in Urban Contexts
- D. D’Ayala ; E. Kishali
- Book Title / Journal: Proceedings of the 15th World Conference on Earthquake Engineering, Lisbon, Portugal
- Year: 2012 , Volume: , Series:
- Earthquake engineering
- Keywords: Vulnerability functions ; masonry ; performance based assessment
- Description
- Masonry buildings are the most common form of dwelling worldwide and at the same time one of the most vulnerable to seismic action. Large numbers of casualties and substantial economic losses are associated with masonry building partial and total collapses in urban and rural areas. Usually studies of vulnerability of masonry structures are conducted within an empirical framework, based on past observation and historic damage data. However empirical approaches have limitation in terms of regional applicability and comparison among different
typological and geographical context. The paper presents an analytical approach, FaMIVE, based on limit state analysis, which allows defining capacity curves and performance points for masonry structures. The analytical development of the procedure from derivation of the ultimate capacity to the identification of the damage states in terms of drift, to the convolution of the capacity and spectral curves to identify performance points for given level of shaking is presented. Fragility curves are then derived. An application to masonry structures in Turkey shows the advantages of this approach. This work was carried out within the framework of the WHE-PAGER project (http://pager.world-housing.net/)
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- Prediction of Higher-Mode Response of Tall RC Wall Buildings
- D. Pennucci ; T.J. Sullivan ; G.M. Calvi
- Book Title / Journal: Proceedings of the 15th World Conference on Earthquake Engineering, Lisbon, Portugal
- Year: 2012 , Volume: , Series:
- Earthquake engineering
- Keywords: performance-based design ; tall buildings ; higher-mode response
- Description
- Recent years have seen a great expansion of the tall building industry, even in areas characterised by high seismicity. With the increase of structural height, the importance of higher-modes in the dynamic response of buildings becomes predominant. However, the effects that ductility has on the response of higher-modes is not yet well understood, and traditional design procedures, based on response spectrum analysis, do not allow for an accurate estimation of higher-mode response of ductile systems. In this study a new approach for estimating the ductile higher-mode response is presented. The procedure consists of a modal analysis combination based on the so-called “substitute structure method”, in which structural properties are suitably modified to account for the
effects of ductility development. The method requires only elastic analysis and can be easily implemented at early stages of design. The proposed approach is validated against the results of an extensive non-linear time history investigation in which several RC wall systems are analysed. It is shown how the proposed methodology gives an improved prediction over the most traditional response spectrum approach for a wide range of different structural parameters and without a significant increase in computational requirements.
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- Simplified Assessment of Railway Masonry Bridges Seismic Capacity
- G. Tecchio ; P. Zampieri ; F. da Porto ; C. Modena ; A. Prota ; G Manfredi
- Book Title / Journal: Proceedings of the 15th World Conference on Earthquake Engineering, Lisbon, Portugal
- Year: 2012 , Volume: , Series:
- Earthquake engineering
- Keywords: Masonry arch bridges ; seismic assessment ; Limit state analysis
- Description
- Masonry arch bridges represent the greatest portion of all the bridges in use in the Italian railway network. The
typological characteristics of these structures were identified on a large stock of 380 bridges located in high
seismicity areas, subdividing them into a set of homogeneous classes. Subsequently a parametrical analysis was performed for each class, in order to calculate the seismic capacity of
the bridges: appropriate ranges for geometrical and mechanical parameters, i.e. span length, arch thickness, spantorise ratio, pier height, etc. were considered, and the limit horizontal load multiplier was calculated for each
relevant collapse mechanism. Finally, envelope curves representing the seismic capacity expressed in terms of limit horizontal acceleration were derived, the input data of which are only easily detectable geometric parameters. These curves can be used for a simplified vulnerability assessment of railway masonry arch bridges, and for prioritizing further investigations and retrofit interventions.
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- Seismic Behaviour of Masonry Arches with Tie-Rods: Dynamic Tests on a Scale Model
- C. Calderini ; S. Lagomarsino ; M. Rossi ; G. Decanio ; M.L. Mongelli ; I. Roselli
- Book Title / Journal: Proceedings of the 15th World Conference on Earthquake Engineering, Lisbon, Portugal
- Year: 2012 , Volume: , Series:
- Earthquake engineering
- Keywords: masonry arches ; Shaking table tests ; displacement capacity
- Description
- In arches and vaults, tie-rods play a decisive role in the control of horizontal thrusts produced by both permanent and seismic loadings. For these reasons, still today tie-rods are widely used as reliable technique for the reinforcement of masonry buildings. Usually, steel bars similar in size and shape to ancient ones and fixed to stonework by means of bolts or plates are adopted. However, some innovative solutions to improve the technique were recently proposed. The common aim of such solutions is to increase the displacement capacity and dissipation of the arch-pillars-rod system under seismic actions. In this paper, the effectiveness of flexible tie-rods to improve the seismic response of arch-pillars system is assessed by mean of shaking table tests and simple analytical models developed in the framework of performance-based design.
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- An Experimental Study on the Out-Of-Plane Stability of Reinforced Masonry Shear Walls Under In-Plane Reversed Cyclic Loads
- N. Azimikor ; B. Robazza ; K. Elwood ; D.L. Anderson ; S. Brzev
- Book Title / Journal: Proceedings of the 15th World Conference on Earthquake Engineering, Lisbon, Portugal
- Year: 2012 , Volume: , Series:
- Earthquake engineering
- Keywords: reinforced masonry ; shear walls ; Seismic resistance
- Description
- This paper presents results of an ongoing two-phase experimental research program on the out-of-plane instability of reinforced masonry (RM) shear walls under seismic loading. Phase 1 involves testing of five reinforced masonry uniaxial specimens under reversed cyclic tension and compression. The specimens represented the end zone of a RM shear wall. The purpose of the testing was to gain insight into the factors influencing out-of-plane instability. The design parameters considered in the study include longitudinal reinforcement ratio and height-to-thickness (h/t) ratio. An analytical model was proposed to estimate the magnitude of critical tensile strain leading to out-of-plane instability. Phase 2 involves experimental and
analytical study of full-scale RM shear wall specimens subjected to reversed-cyclic lateral loading, with the main objective to develop a rational analysis procedure and criteria for assessing the out-of-plane stability of these walls. This paper presents the results of Phase 1 experimental study and explains the Phase 2 experimental
program.
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- In-situ Test for the Shear Strength Evaluation of Masonry: the Case of a Building Hit by L’Aquila Earthquake (Italy)
- M. Candela ; S. Cattari ; S Lagomarsino ; M Rossi ; R. Fonti ; E. Pagliuca
- Book Title / Journal: Proceedings of the 15th World Conference on Earthquake Engineering, Lisbon, Portugal
- Year: 2012 , Volume: , Series:
- Earthquake engineering
- Keywords: in-situ shear test ; masonry ; in-plane behaviour
- Description
- The assessment of historical masonry mechanical parameters, in particular of the shear strength, is one of the
most critical issues related to historical buildings preservation and safety evaluation in seismic area: this is due to the difficulty in performing reliable tests without making an excessive impact on the structure. Many doubts
related to L’Aquila masonry quality, arisen during post-earthquake rehabilitation and reconstruction, might be
solved by destructive in-situ tests. To this aim, a masonry building severely damaged by the 2009 L’Aquila earthquake was chosen as able to execute an in-situ shear tests. The building has been selected by considering different aspects, like as: safety of worker; accessibility; representativeness of masonry for typical historical buildings in the Abruzzo region. This paper focuses on the procedures to carry out the experimental campaign, the analysis of results and their comparison with reference ranges proposed in the Italian Code for Structural Design.
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- What can we do about earthquakes? Towards a systematic approach to seismic risk mitigation.
- David Alexander
- 2012 New Zealand Society of Earthquake Engineering Conference, Paper 001.
- Book Title / Journal:
- Year: 2012 , Volume: , Series:
- Earthquake engineering
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- The influence of pounding on member demands in low rise buildings.
- G.L. Cole ; R.P. Dhakal ; A. Carr ; D.K. Bull
- 2012 New Zealand Society of Earthquake Engineering Conference, Paper 026.
- Book Title / Journal:
- Year: 2012 , Volume: , Series:
- Earthquake engineering
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- Experiments on reinforced concrete frames with brick infill.
- Shyh-Jiann Hwang ; Fu-Pei Hsiao ; Tsung-Chih Chiou
- 2012 New Zealand Society of Earthquake Engineering Conference, Paper 085.
- Book Title / Journal:
- Year: 2012 , Volume: , Series:
- Earthquake engineering
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