Assessment of capacity design of columns in steel moment resisting frames with viscous dampers

Karavasilis, Theodore L.

doi:10.1016/j.soildyn.2016.06.006

Cited by 33 publications

(9 citation statements)

References 25 publications

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“…The same work provided evidence that the formation of column plastic hinges in steel MRFs with viscous dampers does not necessarily lead to worst collapse resistance. A recent work extended the study of Seo et al (2014) to the case of 10-story and 20-story buildings and showed a clear trend of tall steel MRFs with viscous dampers to develop plastic mechanisms that involve column plastic hinges (Karavasilis 2016). The latter work also revealed that column plastic hinges are not particularly detrimental in terms of the collapse resistance and reparability of steel MRFs with viscous dampers.…”

Section: Introductionmentioning

confidence: 61%

Modified capacity design rule for columns in tall steel MRFs with linear viscous dampers within the framework of Eurocode 8

Kariniotakis

Karavasilis

2017

Bull Earthquake Eng

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Seismic design codes enforce a set of capacity design rules for steel moment-resisting frames (MRFs) to promote a ductile sway plastic mechanism that involves plastic hinges in beams and column bases. Previous research showed that these capacity design rules may not be effective for tall steel MRFs with viscous dampers under strong earthquakes due to high axial forces in columns. To address this issue, steel MRFs with linear viscous dampers of different stories are designed according to Eurocode 8 along with using a slightly modified conservative capacity design rule. According to this rule, the axial force for the capacity design of a column in the force path of viscous dampers is calculated as the envelope of the axial force from the peak drift state, and, the axial force from the peak velocity state times a scale factor. This envelope axial force value along with the bending moment and shear force from the peak drift state are used to carry out the capacity design of the column by using the formulae of Eurocode 8, i.e. in the same way with a column of a steel MRF without dampers. Incremental dynamic analyses for 44 earthquake ground motions show that the modified conservative capacity design rule results in steel MRFs with viscous dampers that have plastic mechanisms similar to those of steel MRFs without dampers. Moreover, the proposed capacity design rule becomes stricter for buildings with more than 10 stories to address that available analysis methods for structures with dampers underestimate the peak damper forces in the lower stories of yielding tall steel MRFs. More work is needed to extend the findings of this work to the case of steel MRFs with nonlinear viscous dampers.

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Section: Introductionmentioning

confidence: 61%

Modified capacity design rule for columns in tall steel MRFs with linear viscous dampers within the framework of Eurocode 8

Kariniotakis

Karavasilis

2017

Bull Earthquake Eng

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“…10 that the addition of dampers slightly increased the base shear compared to the bare frame, in the order to 10-15% for the considered distributions. It should be noted that the presence of NVDs may also increase the axial force in the columns, which may require supplemental strengthening of foundations and columns in view of capacity design principles (Karavasilis 2016). Generally, the most critical columns are those located near the supporting braces where the dampers are installed.…”

Section: Seismic Performance Assessmentmentioning

confidence: 99%

Multi-level performance-based design optimisation of steel frames with nonlinear viscous dampers

Domenico

Hajirasouliha

2021

Bull Earthquake Eng

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This paper presents a practical multi-level performance-based optimisation method of nonlinear viscous dampers (NVDs) for seismic retrofit of existing substandard steel frames. A Maxwell model is adopted to simulate the behaviour of the combined damper-supporting brace system, with a fractional power-law force–velocity relationship for the NVDs, while a distributed-plasticity fibre-based section approach is used to model the beam-column members thus incorporating the nonlinearity of the parent steel frame in the design process. The optimum height-wise distribution of the damping coefficients of NVDs satisfying given performance requirements is identified via a uniform damage distribution (UDD) design philosophy. The efficiency of the proposed multi-level performance-based design optimisation is illustrated through nonlinear time-history analysis of 3-, 7- and 12-storey steel frames under both artificial and natural spectrum-compatible earthquakes. Sensitivity analysis is performed to investigate the effects of initial height-wise damping distribution, convergence factor and uncertainty in design ground-motion prediction on the optimisation strategy. The efficiency of the final optimum design solution is also investigated by using drift-based, velocity-based, and energy-based UDD approaches to identify the most efficient performance index parameter for optimisation purposes. It is found that regardless of the selected performance parameter, the optimum damping distribution identified by the proposed methodology leads to frames exhibiting lower maximum inter-storey drift, local damage (maximum plastic rotation) and global damage index compared to an equal-cost uniform damping distribution. However, using drift-based UDD approach generally results in a better seismic performance. It is shown that the proposed UDD optimisation method can be efficiently used to satisfy multiple performance objectives at different intensity levels of the earthquake excitation, in line with performance-based design recommendations of current seismic codes. The proposed method is easy to implement for practical design purposes and represents a simple yet efficient tool for optimum seismic retrofit of steel frames with NVDs.

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“…The behavior of these devices strictly depends on the fluid velocity. Viscous fluid dampers are very versatile and can be designed to allow unconstrained slow thermal motions as well as to provide controlled damping of a structure to protect from wind or earthquakes (Del Gobbo et Al., 2018; Karavasilis et Al., 2016;; De Domenico and Ricciardi 2019). They are typically employed in flexible structures subjected to large and rapid movements like bridges and tall buildings.…”

Section: Introductionmentioning

confidence: 99%

Parametric investigation of the cyclic response of hysteretic steel dampers in braced buildings

Gandelli¹,

Domenico²,

Quaglini³

2021

Preprint

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Hysteretic steel dampers have been effectively used to improve the seismic performance of framed buildings by confining the dissipation of seismic energy into sacrifical, replaceable devices which are not part of the gravity framing system. The number of cycles sustained by the dampers during the earthquake is a primary design parameter, since it can be associated to low-cycle fatigue, with ensuing degradation of the mechanical properties and potential failure of the system. Current standards, like e.g. the European code EN 15129, indeed prescribe, for the initial qualification and the production control of hysteretic steel dampers, cyclic tests in which the devices are assessed over ten cycles with amplitude equal to the seismic design displacement dbd. This paper presents a parametric study focused on the number of effective cycles of the damper during a design earthquake in order to assess the reliability of the testing procedure proposed by the standards. The study considers typical applications of hysteretic steel dampers in low- and medium rise steel and reinforced concrete framed buildings and different ductility requirements. The results point out that the cyclic engagement of the damper is primarily affected by the fundamental period of the braced building and the design spectrum, and that, depending on these parameters, the actual number of cycles can be substantially smaller or larger that that recommended by the standards. A more refined criterion for establishing the number of cycles to be implemented in testing protocols is eventually formulated.

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Assessment of capacity design of columns in steel moment resisting frames with viscous dampers

Cited by 33 publications

References 25 publications

Modified capacity design rule for columns in tall steel MRFs with linear viscous dampers within the framework of Eurocode 8

Modified capacity design rule for columns in tall steel MRFs with linear viscous dampers within the framework of Eurocode 8

Multi-level performance-based design optimisation of steel frames with nonlinear viscous dampers

Parametric investigation of the cyclic response of hysteretic steel dampers in braced buildings

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