Seismic Design of Steel Structures: New Trends of Research and Updates of Eurocode 8

2018 ◽  
pp. 413-438 ◽  
Author(s):  
Raffaele Landolfo
Keyword(s):  
Seismic Design ◽  
Steel Structures ◽  
Eurocode 8

scholarly journals Editorial: New Advances in Seismic Design and Assessment of Steel Structures

2014 ◽  
Vol 8 (1) ◽  
pp. 193-195
Author(s):  
Vincenzo Piluso
Keyword(s):  
Seismic Design ◽  
Steel Structures ◽  
Thematic Issue ◽  
Eurocode 8 ◽  
Braced Frames ◽  
Design Strategies ◽  
Design Procedures ◽  
The Core ◽  
Rbs Connections ◽  
Overall Buckling

In recent years, rapid advances have taken place in earth-quake engineering as applied to steel structures with major emphasis given to (1) development of advanced procedures for seismic performance assessment, (2) development of advanced design procedures for plastic mechanism control, (3) improvements in structural design detailing, (4) better modeling of members and connections for dynamic non-linear analyses, (5) development of new damping devices for supplementary energy dissipation, (6) development of self-centering structural systems, (7) development and testing of new design strategies for reducing structural damage under severe ground motions. Even though such advances have reached in some cases a refinement level justifying their in-troduction in seismic codes, the updating of Eurocode 8 with design criteria and new design strategies reflecting newly developed knowledge is still in delay. In the actual version of Eurocode 8, some advances, such as new structural ty-pologies like braced frames equipped with buckling re-strained braces and dissipative truss moment frames, are still not codified even if they have already gained space in American codes. Because of these rapid advances, weaknesses of Euro-code 8 and new structural typologies to be codified have been recognized and a document focusing on such weak-nesses and new research needs has been published [1]. In particular, the sharing of knowledge obtained has been rec-ognized to be critical to improve the seismic design of steel structures. Therefore, a Thematic Issue on “New Advances in Seismic Design and Assessment of Steel Structures” can be considered timely. Many researchers, all joined by the common interest in design, testing, analysis and assessment of steel structures in seismic areas, have accepted to contribute to this special is-sue. As a result, this thematic issue is composed by eleven contribution covering important design topics for seismic resistant steel structures. Two works [2, 3] are devoted to the seismic design of Concentrically Braced Frames (CBFs), pointing out the drawbacks of the design provisions suggested by Eurocode 8 and also reported in the Italian Technical Code for Construc-tions. In particular, the need to revise the design procedure suggested for columns of CBFs is discussed showing that both the stability and resistance indexes of columns are often exceeded. The results obtained are in agreement with those presented by other researchers [4-8] who recommended de-sign procedures based on a rigorous application of capacity design principles. Also the third manuscript of the thematic issue is devoted to CBFs, but aiming to the development of a new buckling restrained system which can be easily dis-mounted [9]. As it is well known, buckling restrained braces (BRBs) are basically constituted by two parts: an internal slender steel member, known as the “core” and a restraining member, known as the “casing”. The core component has the key role of dissipating energy, while the casing component restrains the brace core from overall buckling in compres-sion. The buckling restraining mechanism can be obtained by enclosing the core (rectangular or cruciform plates, circu-lar rods, etc.) either in a continuous concrete/mortar filled tube or within a “all-steel” casing. Despite of the use of such braces allows to obtain wide and stable hysteresis loops, thus overcoming the main drawbacks of traditional braces due to the poor cyclic response resulting from overall buckling, and their design is already codified in ANSI/AISC 341-10 [10], their use is still not codified in Europe testifying an impor-tant weakness of Eurocode 8. Two papers of the present thematic issue are devoted to beam-to-column connections [11, 12]. The first one [11] presents the results of a wide experimental program recently carried out at Salerno University dealing with extended end plate connections, with and without Reduced Beam Section (RBS), connections with bolted T-stubs and, finally, innova-tive connections equipped with friction dampers. The second work [12] is mainly devoted to the theoretical development of the analysis of the influence of gravity loads on the seis-mic design of RBS connections. In particular, it deserves to be underlined that such influence is commonly neglected in codified rules, such as ANSI/AISC 358-10 [13], because experimental tests constituting the base of the recommended design procedures are typically based on cantilever schemes where gravity loads are not applied.

scholarly journals Methods for conceptual and preliminary seismic design of buildings with steel structure

2019 ◽  
Vol 11 (2) ◽  
Author(s):  
Tiago Ribeiro ◽  
Ana Sousa
Keyword(s):  
Seismic Design ◽  
Steel Structure ◽  
Steel Structures ◽  
Eurocode 8 ◽  
Seismic Action ◽  
The European Union ◽  
Design Standards ◽  
Design Guide ◽  
Current Context ◽  
Earthquake Effects

Throughout the last two decades, seismic design standards evolved to ever more comprehensive and detailed prescriptions, stressing out the need for design methods that deal with earthquake effects not as actions, but as a design philosophy. The Eurocode 8 adoption as national law throughout the European Union countries and informally in many parts of Africa, Asia and Latin America is the pretext for the current study. It aims to provide some guidance to the seismic design of steel structures as well as to the Eurocode 8 implementation by the designers.Some lines on the preliminary design of structural systems were written based on several real cases of structures designed taking into account the seismic action. Such a content is, usually, relevant in any design guide, given its value in enhancing the design technical and economical content. However, it is now of utter significance at the current context as an essential tool to facilitate the safety checking of several code requirements.Some of the Eurocode 8 prescriptions are then decoded, explained and justified based on the supportive bibliography. The information is subsequently ordered as a design guide, where some procedures are proposed to cope with the code interrelated prescriptions and one structural solution is proposed in order to overcome a design challenge while complying with the code.One last but not less relevant addressed issue is the fact that some Eurocode 8 prescriptions may be reviewed, in the eyes of a designer, given its practical outcome. Such issues are identified, explained and some slight code adjustments are suggested.

Global Behavior Factor of Frames with Eccentric Bracings and Relationships with the Ductility Requirements

2013 ◽  
Vol 330 ◽  
pp. 948-953
Author(s):  
Mohamed Oussalem Mechiche ◽  
Ali Bouheraoua ◽  
Farid Chalah ◽  
Ourida Hellal ◽  
Abderrahim Bali
Keyword(s):  
Seismic Design ◽  
Steel Frames ◽  
Steel Structures ◽  
Global Behavior ◽  
Eurocode 8 ◽  
Seismic Loads ◽  
Earthquake Energy ◽  
Behavior Factor

During alternate loading cycles, as during earthquakes, the structure behavior becomes inelastic. This is particularly the case for steel structures. They show a better ability to absorb earthquake energy. This energy dissipating capacity is described by the q global behavior factor as used in the Eurocode 8. However, in other earthquake codes, it is expressed by R letter and in others only the X and V shapes bracing systems are taken into account in the seismic design. In this work, a method for determining the global q behavior factor is presented for eccentrically braced steel frames that are designed to resist seismic loads.

scholarly journals Parametric Analysis of Rotational Effects in Seismic Design of Tall Structures

2021 ◽  
Vol 11 (2) ◽  
pp. 597
Author(s):  
Milan Sokol ◽  
Rudolf Ároch ◽  
Katarína Lamperová ◽  
Martin Marton ◽  
Justo García-Sanz-Calcedo
Keyword(s):  
Seismic Design ◽  
Parametric Study ◽  
Tall Buildings ◽  
Soil Parameters ◽  
Eurocode 8 ◽  
Tall Structures ◽  
Rotational Components ◽  
Different Types ◽  
Depth Study

This paper uses a parametric study to evaluate the significance of the rotational components of Earth’s motion in a seismic design. The parametric study is based on the procedures included in Eurocode 8, Part 6. Although the answer to the question of when the effects of rotational components are important is quite a complex one and requires a more in-depth study, our aim was to try to assess this question in a relatively quick manner and with acceptable accuracy. The first part of the paper is devoted to derivation of a simple formula that can be used for expressing the importance of rotational components in comparison with the classic seismic design without their usage. The quasi-static analysis, assuming inertial forces, is used. A crucial role plays the shape of the fundamental mode of the vibration. Due to simplicity reasons, well-known expression for estimation of the first eigenmode as an exponential function with different power coefficients that vary for different types of buildings is used. The possibility of changing the soil parameters is subsequently included into the formula for estimation of the fundamental frequency of tall buildings. In the next part, the overall seismic analyses of complex FEM models of 3D buildings and chimneys are performed. The results from those analyses are then compared with those from simplified calculations. The importance of the soil characteristics for determination of whether it is necessary to take into account the rotational effects is further discussed.

Structural Performance of Automated Multi-Depth Shuttle Warehouses (Amsws) Under Low-to-Moderate Seismic Actions

2021 ◽  
Author(s):  
Aleksei Kondratenko ◽  
Alper Kanyilmaz ◽  
Carlo Andrea Castiglioni ◽  
Francesco Morelli ◽  
Mohsen Kohrangi
Keyword(s):  
Seismic Design ◽  
Brittle Failure ◽  
Structural Characteristics ◽  
Time History ◽  
Steel Structures ◽  
Current Approach ◽  
Structural Performance ◽  
Future Design ◽  
The Future ◽  
Base Connections

Abstract Automated Multi-Depth Shuttle Warehouses (AMSWs) are compact storage systems that provide a large surface occupation and therefore maximum storage density. AMSWs represent the future of storage technology, providing substantial savings in terms of cost, space, and energy with respect to traditional warehouses. Currently, designers refer to the standard building codes for the seismic design of AMSWs. Since structural characteristics of AMSWs are considerably different from the steel structures of typical buildings, this current approach used by designers is questionable in terms of safety and efficiency. In this article, the behavior of 5 AMSW structures has been studied performing 150 time-history analyses by direct integration including P-Delta effects. Demand/capacity ratios calculated for each element showed the dominance of the brittle failure mechanism in AMSWs subjected to low-to-moderate seismic actions. These mechanisms mainly took place in upright columns and their base connections prior to the activation of ductile energy dissipation mechanisms of the structure. Based on the results, further improvements have been recommended for the future design provisions, which may lead to a safer seismic design of AMSWs.

Lightweight steel systems: Proposal and validation of seismic design rules for second generation of Eurocode 8

2022 ◽  
Vol 172 ◽  
pp. 108826
Author(s):  
Raffaele Landolfo ◽  
Sarmad Shakeel ◽  
Luigi Fiorino
Keyword(s):  
Seismic Design ◽  
Second Generation ◽  
Eurocode 8 ◽  
Design Rules ◽  
Lightweight Steel

Lateral Force Resisting Systems Made of Cold-Formed Steel Material: Proposal of Seismic Design Criteria for 2nd Generation of Eurocode 8

2021 ◽  
Vol 885 ◽  
pp. 127-132
Author(s):  
Sarmad Shakeel ◽  
Alessia Campiche
Keyword(s):  
Seismic Design ◽  
Shear Walls ◽  
Lateral Force ◽  
Background Information ◽  
Design Criteria ◽  
Eurocode 8 ◽  
Building Structures ◽  
Design Standards ◽  
Design Strength ◽  
Cold Formed Steel

The current edition of Eurocode 8 does not cover the design of the Cold-Formed steel (CFS) building structures under the seismic design condition. As part of the revision process of Euro-code 8 to reflect the outcomes of extensive research carried out in the past decade, University of Naples “Federico II” is involved in the validation of existing seismic design criteria and development of new rules for the design of CFS systems. In particular, different types of Lateral Force Resisting System (LFRS) are analyzed that can be listed in the second generation of Eurocode 8. The investigated LFRS’s include CFS strap braced walls and CFS shear walls with steel sheets, wood, or gypsum sheathing. This paper provides the background information on the research works and the reference design standards, already being used in some parts of the world, which formed the basis of design criteria for these LFRS systems. The design criteria for the LFRS-s common to CFS buildings would include rules necessary for ensuring the dissipative behavior, appropriate values of the behavior factor, guidelines to predict the design strength, geometrical and mechanical limitations.

Seismic Performance Assessment of Existing Steel Buildings: A Case Study

2018 ◽  
Vol 763 ◽  
pp. 1067-1076 ◽  
Author(s):  
Luigi di Sarno ◽  
Fabrizio Paolacci ◽  
Anastasios G. Sextos
Keyword(s):  
Numerical Study ◽  
Central Italy ◽  
Steel Structures ◽  
Eurocode 8 ◽  
Building Structures ◽  
Steel Buildings ◽  
Seismic Performance Assessment ◽  
Masonry Infills ◽  
Main Shocks

Numerous existing steel framed buildings located in earthquake prone regions world-wide were designed without seismic provisions. Slender beam-columns, as well as non-ductile beam-to-column connections have been employed for multi-storey moment-resisting frames (MRFs) built before the 80’s. Thus, widespread damage due to brittle failure has been commonly observed in the past earthquakes for steel MRFs. A recent post-earthquake survey carried out in the aftermath of the 2016-2017 Central Italy seismic swarm has pointed out that steel structures may survive the shaking caused by several main-shocks and strong aftershocks without collapsing. Inevitably, significant lateral deformations are experienced, and, in turn, non-structural components are severely damaged thus inhibiting the use of the steel building structures. The present papers illustrates the outcomes of a recent preliminary numerical study carried out for the case of a steel MRF building located in Amatrice, Central Italy, which experienced a series of ground motion excitations suffering significant damage to the masonry infills without collapsing. A refined numerical model of the sample structure has been developed on the basis of the data collected on site. Given the lack of design drawings, the structure has been re-designed in compliance with the Italian regulations imposed at the time of construction employing the allowable stress method. The earthquake performance of the case study MRF has been then investigated through advanced nonlinear dynamic analyses and its structural performance has been evaluated according to Eurocode 8-Part 3 for existing buildings. The reliability of the codified approaches has been evaluated and possible improvements emphasized.

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