scholarly journals Removable friction dampers for low-damage steel beam-to-column joints

2021 ◽  
Author(s):  
Massimo Latour ◽  
Mario D'Aniello ◽  
Gianvittorio Rizzano ◽  
Vincenzo Piluso ◽  
Mariana Zimbru ◽  
...  
Keyword(s):  
Structural Damage ◽  
Vertical Direction ◽  
Experimental Tests ◽  
Steel Plates ◽  
Friction Dampers ◽  
Steel Moment Resisting Frames ◽  
First Case ◽  
Lower Beam ◽  
Moment Resisting ◽  
Design Requirements

Beam-to-column joints equipped with friction dampers are promising solutions to improve the performance of steel moment resisting frames due to the possibility to guarantee large dissipation capacity limiting the structural damage under severe seismic conditions. In this paper, the experimental tests and the numerical simulations of two types of joints are shown and discussed with the aim of developing pre-qualified configurations. The friction dampers are designed to be easily removable from both the lower beam flange and the column face by means of bolted connections. The devices are composed of a stack of steel plates conceived to assure symmetrical friction. The friction surface is set in vertical direction in first case and in horizontal direction in the second type. The experimental tests confirmed the effectiveness of both examined joints and the finite element analyses allowed characterizing their local response, thus providing additional insights to improve the design requirements.

scholarly journals EXPERIMENTAL RESPONSE OF A LOW-YIELDING, SELF CENTERING, ROCKING COLUMN BASE JOINT WITH FRICTION DAMPERS

2021 ◽  
Author(s):  
Massimo Latour ◽  
Gianvittorio Rizzano
Keyword(s):  
Energy Dissipation ◽  
The Self ◽  
Friction Dampers ◽  
Steel Moment Resisting Frames ◽  
Moment Resisting ◽  
Restoring Forces ◽  
Energy Dissipation System ◽  
Unloading Stiffness ◽  
Column Bases ◽  
Column Base

The sliding hinge joint (SHJ) is a supplemental energy dissipation system for column bases or beam-to-column connections of steel Moment Resisting Frames (MRFs). It is based on the application of symmetric/asymmetric friction dampers to develop a dissipative mechanism alternative to the column/beam yielding. This typology was initially proposed in New Zealand and, more recently, is starting to be tested and applied also in Europe. While on the one hand this technology provides great benefits such as the damage avoidance, on the other hand, due to the high unloading stiffness of the dampers in tension or compression, its cyclic response is typically characterized by a limited self-centering capacity.To address this shortcoming, the objective of the work herein presented is to examine the possibility to add to these connections also a self-centering capacity proposing new layouts based on a combination of friction devices (providing energy dissipation capacity), pre-loaded threaded bars and disk springs (introducing in the joint restoring forces).In this paper, as a part of an ongoing wider experimental activity regarding the behavior of self-centering connections, the attention is focused on the problem of achieving the self-centering of the column bases of MRFs by studying a detail consisting in a column-splice equipped with friction dampers and threaded bars with Belleville disk springs, located above a traditional full-strength column base joint. The main benefits obtained with the proposed layout are that: (i) the self-centering capability is obtained with elements (threaded bars and Belleville springs) which have a size comparable to the overall size of the column-splice cover plates; (ii) all the re-centering elements are moved far from the concrete foundation avoiding any interaction with the footing. The work reports the main results of an experimental investigation and the analysis of a MRF equipped with the proposed column base joints.

Damage Avoidance Self-Centering Steel Moment Resisting Frames (MRFs) Using Innovative Resilient Slip Friction Joints (RSFJs)

2018 ◽  
Vol 763 ◽  
pp. 726-734 ◽  
Author(s):  
Ashkan Hashemi ◽  
Pouyan Zarnani ◽  
Farhad Mohammadi Darani ◽  
Armin Valadbeigi ◽  
George Charles Clifton ◽  
...  
Keyword(s):  
Experimental Tests ◽  
Steel Moment Resisting Frames ◽  
Residual Drift ◽  
Moment Resisting Frames ◽  
Moment Resisting ◽  
Gap Opening ◽  
Ductile Behavior ◽  
Design Earthquake ◽  
Determining Factor ◽  
Damage Avoidance

Higher seismic performance can be achieved by localizing the inelastic deformation in the connections (fuses) and minimizing the residual drift that are often a determining factor in whether a structure can be repaired or re-occupied after an earthquake. This paper introduces the self-centering damage avoidance steel Moment Resisting Frames (MRFs) using innovative Resilient Slip Friction Joints (RSFJs). The RSFJ provides self-centering and energy dissipation in one compact package requiring no post-event maintenance. In this concept, the beam is connected to the column through a pinned joint at the top, an RSFJ at the bottom and a slotted web plate for transferring the shear forces, when required. The RSFJ allows for gap opening in the connection upon loading and then re-centers the system when unloading. Furthermore, a secondary fuse within the RSFJ is considered to keep maintaining a ductile behavior in the system in case of an earthquake larger than the design earthquake. The conducted experimental tests confirmed the outcomes of this study.

scholarly journals On the Seismic Response of Protected and Unprotected Middle-Rise Steel Frames in Far-Field and Near-Field Areas

2014 ◽  
Vol 2014 ◽  
pp. 1-11 ◽  
Author(s):  
Dora Foti
Keyword(s):  
Seismic Response ◽  
Ground Motions ◽  
Near Field ◽  
Shaking Table ◽  
Far Field ◽  
Base Shear ◽  
Friction Dampers ◽  
Steel Moment Resisting Frames ◽  
Damage Indices ◽  
Moment Resisting

Several steel moment-resisting framed buildings were seriously damaged during Northridge (1994); Kobe (1995); Kocaeli, Turkey (1999), earthquakes. Indeed, for all these cases, the earthquake source was located under the urban area and most victims were in near-field areas. In fact near-field ground motions show velocity and displacement peaks higher than far-field ones. Therefore, the importance of considering near-field ground motion effects in the seismic design of structures is clear. This study analyzes the seismic response of five-story steel moment-resisting frames subjected to Loma Prieta (1989) earthquake—Gilroy (far-field) register and Santa Cruz (near-field) register. The design of the frames verifies all the resistance and stability Eurocodes’ requirements and the first mode has been determined from previous shaking-table tests. In the frames two diagonal braces are installed in different positions. Therefore, ten cases with different periods are considered. Also, friction dampers are installed in substitution of the braces. The behaviour of the braced models under the far-field and the near-field records is analysed. The responses of the aforementioned frames equipped with friction dampers and subjected to the same ground motions are discussed. The maximum response of the examined model structures with and without passive dampers is analysed in terms of damage indices, acceleration amplification, base shear, and interstory drifts.

Experimental Tests on Extended Stiffened End-Plate Joints within Equal Joints Project

2018 ◽  
Vol 763 ◽  
pp. 406-413 ◽  
Author(s):  
Mario D'Aniello ◽  
Roberto Tartaglia ◽  
Silvia Costanzo ◽  
Giuseppe Campanella ◽  
Raffaele Landolfo ◽  
...  
Keyword(s):  
Mechanical Behavior ◽  
Experimental Tests ◽  
The Other ◽  
Analytical Models ◽  
Project Design ◽  
Design Rules ◽  
Steel Moment Resisting Frames ◽  
End Plate ◽  
Other Hand ◽  
Moment Resisting

Bolted extended stiffened end-plate beam-to-column joints are commonly used for steel moment resisting frames in seismic areas. In the framework of European codes, EN 1993:1-8 provides the design rules and the analytical models to predict the mechanical behavior of the joints. On the other hand, EN 1998-1 specifies the required performance for seismic resistant joints. Within EQUALJOINTS project design rules have been developed and experimental tests were carried out to seismically prequalify extended stiffened end-plate joints. In this paper the proposed design rules are discussed and results of the experimental tests are described.

Performance-based assessment of seismic-resilient steel moment resisting frames equipped with innovative column base connections

Structures ◽  
2021 ◽  
Vol 32 ◽  
pp. 1646-1664
Author(s):  
Elena Elettore ◽  
Annarosa Lettieri ◽  
Fabio Freddi ◽  
Massimo Latour ◽  
Gianvittorio Rizzano
Keyword(s):  
Steel Moment Resisting Frames ◽  
Moment Resisting Frames ◽  
Performance Based Assessment ◽  
Moment Resisting ◽  
Base Connections ◽  
Column Base
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