Seismic design of CLT Buildings: Definition of the suitable q-factor by numerical and experimental procedures

2013 ◽  
pp. 118-125 ◽  
Keyword(s):  
Seismic Design ◽  
Q Factor ◽  
Definition Of

scholarly journals Analysis of Equivalent Diaphragm Vault Structures in Masonry Construction under Horizontal Forces

Heritage ◽  
2020 ◽  
Vol 3 (3) ◽  
pp. 989-1017
Author(s):  
Pier Silvio Marseglia ◽  
Francesco Micelli ◽  
Maria Antonietta Aiello
Keyword(s):  
Seismic Design ◽  
Complex Geometry ◽  
Geometrical Parameters ◽  
Masonry Building ◽  
Masonry Construction ◽  
Horizontal Connections ◽  
Historical Masonry ◽  
Side Walls ◽  
Definition Of ◽  
The Ideal

In seismic areas, masonry construction is prone to brittle failures due to the mechanical behavior of the constituent materials and to the low capacity of force redistributions. The redistribution capacity is mainly due to the presence of horizontal connections upon the walls and to the stiffness of the roof, which is typically a vaulted structure. The modeling of the global behavior of a masonry building, taking into account the accurate stiffness of the vaults, is a major issue in seismic design and assessment. The complex geometry of the vaults can be considered as an equivalent plate, able to replicate the stiffness behavior and the force redistribution capacity of the real vault. In this study, the efforts of the authors are addressed to the definition of a plate, able to replace the vaulted surfaces in a global numerical model. The ideal diaphragm is considered as a generally orthotropic plate with the same footprint and the same thickness of the original vault. An extended parametric study was conducted in which the mechanical and geometrical parameters were varied, such as the vault thickness, its dimensions, the constraint conditions, and the possible presence of side walls. The results are presented and discussed herein, with the aim of providing useful information to the researchers and practitioners involved in seismic analyses of historical masonry construction.

scholarly journals Considerations for a "design" earthquake

1972 ◽  
Vol 5 (2) ◽  
pp. 47-50
Author(s):  
G. L. Evans
Keyword(s):  
Soil Properties ◽  
Seismic Design ◽  
Soil Mass ◽  
Soil Dynamics ◽  
Simplifying Assumptions ◽  
Acceleration Method ◽  
Risk Magnitude ◽  
Definition Of ◽  
Design Earthquake ◽  
Relative Factors

Any structure is only as good as its foundation material. Under earthquake the properties of foundation materials can change drastically. Recent advances in soil dynamics indicate that the simplifying assumptions on which our seismic building code is based, are not adequate to cater for the variations in foundation conditions. The code provides
clear definition of seismic design forces, in terms of acceleration and period, but ignores any possible effects of displacement, velocity or wavelength. Currently available methods of design and analysis can provide for calculation of ground period, displacements, velocities, accelerations and stress values at any point in a soil mass. Although not perhaps suitable
for detailed code recommendations these methods can be used by designers where needed and the code could contain simplified but conservative data on the use of such methods, The design forces to be imposed on a structure and variations of these are defined exactly in the code, but these are not matched by the definition of base motions, which are influenced by magnitude of the earthquake, distance and soil properties. It should be possible to provide for a "design earthquake" which takes into account, type of structure, nature of
 risk, magnitude of earthquake, distance from active seismic areas and soil properties. Even relative factors, initially based on overseas research, relating these things would provide a more rational basis for seismic effects on structures than the simplified structure mass acceleration method used at present.

scholarly journals Safety of Nuclear Power Plants with Respect to the Fault Displacement Hazard

2020 ◽  
Vol 10 (10) ◽  
pp. 3624
Author(s):  
Tamás János Katona
Keyword(s):  
Seismic Design ◽  
Nuclear Power ◽  
Power Plants ◽  
Nuclear Power Plants ◽  
Ground Displacement ◽  
Design Basis ◽  
Hazard Level ◽  
Definition Of ◽  
Fault Displacement ◽  
Probabilistic Criteria

The hazard of permanent ground displacements/deformations can challenge the safety of the nuclear power plants. Increasing knowledge of the hazard and development of methods for structure–fault–displacement interaction motivates the designing of nuclear power plants for permanent ground displacement instead of abandoning the sites that could be affected by this kind of hazard. For the design basis, permanent ground displacement should be defined at the hazard level that complies with the probabilistic criteria for accounting for the natural hazards in the design that also ensure compliance with probabilistic safety criteria. In this paper, a procedure is proposed for the definition of the design basis permanent ground displacement that is based on the deaggregation of seismic design basis hazard. The definition of the displacement for the margin evaluation is also proposed. The feasibility of safe design is also demonstrated for the proposed definition of design basis hazard via qualitative judgement on the sensitivity of the structures, systems and components ensuring the fundamental safety functions with respect to the permanent ground displacement that is supported by existing case studies.

scholarly journals Comparative study of codes for the seismic design of structures

2012 ◽  
Vol 5 (6) ◽  
pp. 812-819
Author(s):  
S. H. C. Santos ◽  
S. S. Lima ◽  
A. Arai
Keyword(s):  
Seismic Design ◽  
Response Spectra ◽  
Soil Liquefaction ◽  
Eurocode 8 ◽  
South American ◽  
The South ◽  
Seismic Zonation ◽  
Seismic Force ◽  
Western Border ◽  
Definition Of

A general evaluation of some points of the South American seismic codes is presented herein, comparing them among themselves and with the American Standard ASCE/SEI 7/10 and with the European Standard Eurocode 8. The study is focused in design criteria for buildings. The Western border of South America is one of the most seismically active regions of the World. It corresponds to the confluence of the South American and Nazca plates. This region corresponds roughly to the vicinity of the Andes Mountains. This seismicity diminishes in the direction of the comparatively seismically quieter Eastern South American areas. The South American countries located in its Western Border possess standards for seismic design since some decades ago, being the Brazilian Standard for seismic design only recently published. This study is focused in some critical topics: definition of the recurrence periods for establishing the seismic input; definition of the seismic zonation and design ground motion values; definition of the shape of the design response spectra; consideration of soil amplification, soil liquefaction and soil-structure interaction; classification of the structures in different importance levels; definition of the seismic force-resisting systems and respective response modification coefficients; consideration of structural irregularities and definition of the allowable procedures for the seismic analyses. A simple building structure is analyzed considering the criteria of the several standards and obtained results are compared.

scholarly journals The Reactive and Radiation Electromagnetic Energies of Antennas: A New Formulation

2020 ◽  
Author(s):  
gaobiao xiao
Keyword(s):  
Additional Term ◽  
Radiation Energy ◽  
Q Factor ◽  
Small Sphere ◽  
Radiation Fields ◽  
Accurate Definition ◽  
Long Time ◽  
Whole Space ◽  
Definition Of ◽  
New Formulation

<p>It is required to calculate the stored reactive energy of an antenna in order to evaluate its Q factor. Although it has been investigated for a long time, some issues still need further clarification. The main difficulty involved is that the reactive energy of an antenna tends to become infinitely large when integrating the conventionally defined energy density in the whole space outside a small sphere containing the antenna. The reactive energy is usually made to be bounded by subtracting an additional term associated with the radiation fields. However, there exists no well-accepted accurate definition for this additional term that is valid for all cases. By re-checking the definition of reactive energies, a new formulation is proposed in this paper which can separate the reactive energy and the radiation energy explicitly based on source-potentials. The clearly defined reactive energy is bounded without necessity to subtract that additional term, and the resultant formulae are easy to implement.</p>

scholarly journals Comparative Study of Codes for Seismic Design of Structures

2013 ◽  
Vol 9 (1) ◽  
pp. 1-12 ◽  
Author(s):  
Sergio Hampshire De C. Santos ◽  
Luca Zanaica ◽  
Carmen Bucur ◽  
Silvio De Souza Lima
Keyword(s):  
Seismic Design ◽  
Model Building ◽  
Seismic Analysis ◽  
Response Spectra ◽  
Soil Conditions ◽  
Seismic Zonation ◽  
Seismic Input ◽  
Local Soil ◽  
Seismic Force ◽  
Definition Of

Abstract This paper presents a comparative evaluation among some international, European and American, seismic design standards. The study considers the criteria for the analysis of conventional (residential and commercial) buildings. The study is focused on some critical topics: definition of the recurrence periods for establishing the seismic input; definition of the seismic zonation and shape of the design response spectra; consideration of local soil conditions; definition of the seismic force-resisting systems and respective response modification coefficients; definition of the allowable procedures for the seismic analysis. A model for a standard reinforced concrete building (“Model Building”) has been developed to permit the comparison among codes. This building has been modelled with two different computer programs, SAP2000 and SOFiSTiK and subjected to seismic input according to the several seismic codes. The obtained results compared are leading to some important conclusions.

scholarly journals Seismic design of acceleration-sensitive non-structural elements in New Zealand: State-of-practice and recommended changes

2021 ◽  
Vol 54 (4) ◽  
pp. 243-262
Author(s):  
Muhammad Rashid ◽  
Rajesh Dhakal ◽  
Timothy Sullivan
Keyword(s):  
New Zealand ◽  
Seismic Design ◽  
Design Procedure ◽  
International Perspective ◽  
Eurocode 8 ◽  
Engineering Systems ◽  
Structural Elements ◽  
Seismic Loadings ◽  
Improved Design ◽  
Definition Of

Acceleration-sensitive non-structural elements not only constitute a significant portion of a building’s component inventory, but also comprise components and systems that are indispensable to the operational continuity of essential facilities. In New Zealand, Section 08 of the seismic loadings standard, NZS 1170.5: Earthquake Actions, and a dedicated standard, NZS 4219: Seismic Performance of Engineering Systems in Buildings, address the seismic design of non-structural elements. This paper scrutinizes the design provisions for acceleration-sensitive non-structural elements in NZS 1170.5 and NZS 4219, and provides an international perspective by comparing with the design provisions for non-structural elements specified in ASCE 7-16, the latest ATC approach and Eurocode 8. This is followed by a detailed discussion on the improvements required for component demand estimation, the need for design criteria that are consistent with performance objectives, definition of realistic ductility factors, and recommendations for the future way forward in the form of an improved design procedure and its application through a new seismic rating framework.

scholarly journals Seismic Design of Grana Cheese Cold-Formed Steel Racks

Buildings ◽  
2020 ◽  
Vol 10 (12) ◽  
pp. 246
Author(s):  
Claudio Bernuzzi ◽  
Marco Simoncelli
Keyword(s):  
Seismic Design ◽  
Response Spectrum ◽  
Time History ◽  
Steel Columns ◽  
Steel Members ◽  
Cold Formed Steel ◽  
European Standards ◽  
Definition Of ◽  
Nonlinear Time History ◽  
Grana Cheese

Since few years ago only one typology of racks was used to store Grana cheese wheels for aging, which was designed focusing on the sole static behavior. Battened steel columns made by vertical tubes welded to horizontal angles were connected by means of wood boards supporting the wheels. In 2012, a strong earthquake occurred in Emilia Romagna (Italy) and a great number of these structures collapsed owing to the absence of checks for resistance against earthquakes. This catastrophic event plus the need to maximize the structural efficiency led to the development of a new typology of rack systems based on the use of cold-formed steel members. Owing to an extremely limited state-of-the-art on these modern cheese rack, design is carried out in agreement with the standard provisions calibrated and proposed for adjustable pallet racks, despite the non-negligible differences between these structural systems. The paper is focused on the comparison between the available seismic design approaches for cheese rack in order to highlight their main advantages and limits. In particular, among the four design approaches admitted in the European standards, the modal response spectrum analysis (MRSA) and the nonlinear time-history (NLTH) have been considered and the associated results compared in terms of maximum safety index of the members, global displacements and interstorey drifts. Research outcomes stress the differences associated with the considered approaches in terms of expected performance underlining the importance of an accurate definition of the behavior (q-) factor.

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