The lack of empirical data regarding earthquake damage or losses has propelled the development of dozens of analytical methodologies for the derivation of fragility and vulnerability functions. Eac...

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Current Challenges and Future Trends in Analytical Fragility and Vulnerability Modeling

Seismic resilient steel structures: A review of research, practice, challenges and opportunities

Dual seismic-resistant steel frame with high post-yield stiffness energy-dissipative braces for residual drift reduction

A beam-to-column connection with visco-elastic and hysteretic dampers for seismic damage control

Earthquake Engng Struct Dyn. 2020;49:261–284. Summary The achievement of adequate performance objectives for buildings under increasing seismic intensities is not only related to the performance of structural members but also to the behavior of nonstructural elements. The need to properly design nonstructural elements for earthquakes has been largely demonstrated in the last few years and has become an important objective within the earthquake engineering community. A crucial aspect in the proper design of nonstructural elements is the definition of the seismic demand in terms of both absolute acceleration and relative displacement floor response spectra. In the first part of this study, relative displacement and absolute acceleration floor response spectra were computed for four reinforced concrete moment‐resisting archetype frames via dynamic time‐history analyses and were compared with floor response spectra predicted by means of two recent simplified methodologies available in the literature. It was observed that one of the existing methodologies is generally unable to predict consistent absolute acceleration and relative displacement floor response spectra. An improved procedure is developed for estimating consistent floor response spectra for building structures subjected to low and medium‐high seismic intensities. This new procedure improves the predictions of a relative displacement floor response spectrum by constraining its ordinates at long nonstructural periods to the expected peak absolute displacement of the floor. The resulting acceleration and relative displacement response spectra are then consistently related by the well‐known pseudo‐spectral relationship over the entire nonstructural period range. The effectiveness of the proposed methodology was appraised against floor response spectra computed from nonlinear time‐history analyses.

Consistent floor response spectra for performance‐based seismic design of nonstructural elements

Experimental analysis of seismic resistant composite steel frames with dissipative devices

Welded fuses for dissipative beam-to-column connections of composite steel frames: Numerical analyses

Numerical investigations of repairable dissipative bolted fuses for earthquake resistant composite steel frames

Steel storage racks are typically made of thin-walled cold formed steel profiles, which prove to be the most versatile, economic and sustainable elements for industrial rack construction. Their lightweight structural systems are usually designed to resist heavy load units, reaching considerable heights. However, the global behavior of storage racks under seismic actions is much less predictable than the behavior of steel buildings made of standard steel profiles and connections, mainly due to the perforations in their thin walled upright columns, and their semi-rigid beam-column and base plate joints. Full scale experimental investigations are greatly needed in order to understand and quantify the global performance of storage racks, and improve their design for seismic actions. For the first time in Europe, thanks to the funding provided by Research Fund for Coal and Steel (RFCS), an extensive full-scale push-over testing program has been carried out on 8 fully-loaded pallet racking specimens (4 unbraced and 4 braced racks), provided by 4 different international rack producers. This paper presents the experimental results of full scale push-over tests performed in the down-aisle (longitudinal) direction on fully-loaded unbraced specimens. In particular, experimental global capacity curves of the tested specimens are presented, discussing the key factors influencing the racks’ response, as well as the failure mechanisms of the different rack typologies. Furthermore, the behavior factor (q) values of each specimen are derived from re-analysis of the test results. Vulnerability of unbraced racks to soft-storey mechanism is demonstrated, highlighting its causes. Design guidelines are provided in order to guarantee a globally homogenous ductility under seismic actions, along with the new safety requirements for the design of the floor connections of unbraced racks.

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Alper Kanyilmaz

Papers

Experimental analysis of seismic resistant composite steel frames with dissipative devices

Welded fuses for dissipative beam-to-column connections of composite steel frames: Numerical analyses

Numerical investigations of repairable dissipative bolted fuses for earthquake resistant composite steel frames

Experimental assessment of the seismic behavior of unbraced steel storage pallet racks

Reducing the seismic vulnerability of existing elevated silos by means of base isolation devices