- Seismic Assessment of a 15-Story Building Damaged in the Chile Earthquake of February 27th 2010
- M. Kohrangi ; 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: seismic assessment ; Chile earthquake
- Description
- This paper considers the seismic assessment of a 15-storey RC structural wall building, Alto Rio,
located in the city of Concepción that collapsed in the M8.8 Chile earthquake of Feb 27th 2010. Different methods of assessment, based on FEMA356, are applied to examine if the observed damage could have been anticipated. Results show that FEMA356 assessment methods would have identified that the building was likely to be damaged in a major earthquake. Severe irregularities and discontinuity of walls at the base of the structure, in general, and lack of ductile detailing in walls and coupling beams are identified as the likely reasons for the damage. In addition to this assessment, the design procedures that are expected to have been used for the original design of the building are reviewed. The results showed that in applying the code design procedure, wall axial tensile forces were probably underestimated and improved capacity design procedures should be implemented.
PDF |
- Seismic Design of Cable-stayed Bridges. The South Crossing Bridge in Guayaquil, Ecuador
- G.M. Calvi ; M. Moratti ; A. Villani ; D. Pietra ; R. Pinho
- Book Title / Journal: Proceedings of the 15th World Conference on Earthquake Engineering, Lisbon, Portugal
- Year: 2012 , Volume: , Series:
- Earthquake engineering
- Keywords: Cable-Stayed Bridges ; Seismic Design ; Viscous Damper
- Description
- Seismic design of long-span Cable-Stayed bridges has received a strong input in the latest decades, from both conceptual design and construction point of view, thanks to latest examples of design and
realizations of long-span Cable-Stayed bridges in high seismic areas where some of them have already
proved the success of the newly adopted conceptual designs. Within the proposed approach, the structural performance is ensured through the adoption of passive dissipation devices together with structural configurations substantially new for such kind of bridges. The confidence gained towards
this innovative approach for seismic protection of long-span bridges further promotes the attempt to
adopt those challenging structures as means for bridging morphological and economical gaps which
for long time have distressed the natural evolution of commercial flows and economical growth of entire countries, particularly of those highly prone to natural hazards such as earthquakes. The paper
illustrates the case study of the South Crossing Bridge in Guayaquil, Ecuador, from preliminary evaluations till the final design solutions adopted for its seismic protection.
PDF |
- 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.
PDF |
- 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.
PDF |
- 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.
PDF |
- 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.
PDF |
- Is direct displacement based design valid for long span bridges?
- L. Petrini ; G.M. Calvi ; G. Adhikari
- 14th World Conference on Earthquake Engineering, Beijing, China
- Book Title / Journal:
- Year: 2008 , Volume: , Series:
- Earthquake engineering
PDF |
- New methods for assessment and design of structures in seismic zones: present state and research needs
- S. Pampanin ; M. Dolsek ; G.M. Calvi ; P. Fajfar
- International Workshop on Mitigation of Seismic Risk, Belgirate (VB), Italy.
- Book Title / Journal:
- Year: 2000 , Volume: , Series:
- Earthquake engineering
PDF |
