The effect of rotational component of earthquake excitation on the response of steel structures

ce/papers ◽  
2021 ◽  
Vol 4 (2-4) ◽  
pp. 1887-1892
Author(s):  
Nikos Pnevmatikos ◽  
Foteini Konstandakopoulou ◽  
Georgios Papavasileiou ◽  
George Papagiannopoulos ◽  
Pantelis Broukos
Keyword(s):  
Steel Structures ◽  
Rotational Component ◽  
Earthquake Excitation

scholarly journals Influence of Earthquake Rotational Components on the Seismic Safety of Steel Structures

Vibration ◽  
2020 ◽  
Vol 3 (1) ◽  
pp. 42-50
Author(s):  
Nikos Pnevmatikos ◽  
Foteini Konstandakopoulou ◽  
George Papagiannopoulos ◽  
George Hatzigeorgiou ◽  
Georgios Papavasileiou
Keyword(s):  
Seismic Analysis ◽  
Response Spectrum ◽  
Steel Structures ◽  
Rotational Component ◽  
Structural Behaviour ◽  
Earthquake Excitation ◽  
History Analysis ◽  
Rotational Components ◽  
Response History Analysis ◽  
The Impact

In this work a seismic analysis of structure associated with the complete description of ground motion components is performed. All earthquake excitation components corresponding to the six degrees of freedom, translational and rotational ones need to be taken into account for a realistic simulation of structural performance. The impact of the rotational components of an earthquake to the overall response of a steel structure is examined. Typically, in response to the history analyses, the seismic input is descripted by its translational component only, while the rotational components are ignored. This is because the rotational component requires special devices to be recorded in adequate detail. This is one of the reasons why this component is often ignored. With the currently available technology, such an instrument can be constructed and provide detailed records that can be used for the response history analysis of structures. The applicable design codes using a simplified response spectrum analysis accounting for rotational components is proposed and elastic design response spectra are introduced. Another reason why the rotational component was not taken into account in structural analysis is that it does not have significant effect on low-rise buildings. In this work, the analysis results in terms of response and internal forces when accounting for the rotational component is demonstrated. A case study on the response history analysis of symmetrical and non-symmetrical steel structures subjected to earthquake excitation with and without the rotational component of the excitation was performed. Numerical results show that the influence of the rotational component on the structural behaviour is important and should be taken into account in the design process.

The Effects of Various Slippage Loads on the Response Modification Factor of Steel Structures Equipped with Frictional Dampers

2015 ◽  
Vol 15 (06) ◽  
pp. 1450080
Author(s):  
Hamid Rahmani Samani ◽  
Masoud Mirtaheri ◽  
Mojtaba Rafiee
Keyword(s):  
Structural Control ◽  
Steel Structures ◽  
Earthquake Excitation ◽  
Response Modification Factor ◽  
Steel Moment Resisting Frames ◽  
Optimum Energy ◽  
Seismic Design Code ◽  
Moment Resisting ◽  
Modification Factor ◽  
Code Procedure

A common and successful way of structural control is to dissipate the seismic kinetic energy via frictional dampers. Response of a friction damped frame during an earthquake excitation is heavily dependent to the slippage limit of the frictional dampers. Low values of slippage load may lead to excessive deformations while large slippage loads may prevent sliding. Therefore, selecting appropriate values for slippages loads of the dampers is very important in order to have optimum energy dissipating system. Utilizing a response modification factor, the standard seismic design code procedure can be applied to the frames equipped with frictional dampers to determine the value of slippage loads. In this investigation, the response modification factor of steel moment resisting frames equipped with frictional dampers is evaluated considering the effects of various slippage loads. The response modification factor is calculated for two bay widths of 5 m and 7 m in length. It is shown that the optimum slippage load that results in the maximum response modification factor is in the range of 8% to 20% of the total weight of the structure. The taller the structure is, the less the optimum slippage load will be. Finally, an equation is proposed for the response modification factor as a function of the slippage load.

Seismic base isolation for steel structures

1985 ◽  
Vol 12 (1) ◽  
pp. 73-81
Author(s):  
S. F. Stiemer ◽  
B. B. Barwig
Keyword(s):  
Base Isolation ◽  
Steel Structures ◽  
Experimental Tests ◽  
Shaking Table ◽  
Earthquake Ground Motion ◽  
Experimental Investigations ◽  
Steel Buildings ◽  
Earthquake Excitation ◽  
Isolation System ◽  
Base Isolation System

Base isolation is a strategy for a design of buildings in areas where seismic loads govern. It enables the reduction of earthquake excitation to an acceptable level, without an increase of structural acceleration. This paper presents the results of the experimental investigations of various schemes of first-storey designs for steel buildings with base isolation.A scaled-down steel frame building was used for the shaking table tests, which were conducted in the Earthquake Simulator Laboratory of the University of British Columbia. The base-storey design was altered while the dynamic response of the frame was recorded. The base isolation consisted of steel roller bearings with parallel steel yield rings, to limit excessive displacements and provide wind restraint.The proposed base storey is substantially different from conventional solutions. The variation in the base-storey design was aimed at the elimination of the blind base storey or double foundation in order to increase the economy of the base-isolation system. The experimental tests showed suitable design approaches, and analytical studies to optimize them will follow.It was verified that uncoupling of buildings from the earthquake ground motion is relatively simple to achieve. Certain restraint is required to resist wind and other horizontal loads. This is usually achieved by mechanical fuses or energy absorbers. A solid state energy absorber was used in the described tests. Key words: base-isolation system for buildings, earthquake-resistant steel structures, experimental investigations, retrofit system.

Influence of Rotational Component of Earthquake Excitation to the Response of Steel Slender Frame

2019 ◽  
Vol 968 ◽  
pp. 294-300 ◽  
Author(s):  
Nikos G. Pnevmatikos ◽  
Georgios S. Papavasileiou ◽  
Fotini D. Konstandakopoulou ◽  
George Papagiannopoulos
Keyword(s):  
Time History ◽  
Response Spectra ◽  
Steel Frame ◽  
Rotational Component ◽  
Earthquake Excitation ◽  
History Analysis ◽  
Rotational Components ◽  
Internal Forces ◽  
Elastic Design ◽  
The Impact

This work is about the influence of rotational component of earthquake excitation to the response of high steel slender frames. In most of studies seismic input is being represented by translational only component of ground accelerations while the rotational one is ignored. This was due to the luck of records which measure the rotational component. Nowadays, technology provides such an instruments and relative records can be found. Elastic design response spectra for rotational components are introduced in regulations. Furthermore, the rotational component was not taken into account since its influence in low structures is not significant. In this paper the results in response and in internal forces of rotational component to the slender steel frame is examined. Time history analysis of a ten-story steel frame with and without rotational excitation component is performed. From the numerical results it is shown that the impact of rotational component in response and the internal forces of the frame is significant and should not be ignored to the design of structures.

scholarly journals Problems of Collisions Between Adjacent Steel Structures under Earthquake Excitation / Problemy Zderzeń Pomiędzy Sąsiadującymi Konstrukcjami Stalowymi Poddanymi Obciążeniom Sejsmicznym

2016 ◽  
Vol 20 (1) ◽  
pp. 147-158
Author(s):  
Barbara Sołtysik ◽  
Robert Jankowski
Keyword(s):  
Ground Motions ◽  
Structural Response ◽  
Steel Structures ◽  
Experimental Tests ◽  
Separation Distance ◽  
Structural Elements ◽  
Earthquake Excitation ◽  
Significant Damage ◽  
High Level ◽  
Strong Ground

Abstract Nowadays, the high level of urbanization forces the engineers to design closelyseparated structures and to take into account many factors influencing their response, including collisions between them due to insufficient separation distance during moderate to strong ground motions. Recent observations as well as experimental and numerical investigations have confirmed that interactions between structures may lead to significant damage of structural elements and even to its total collapse. The aim of this paper is to investigate the influence of collisions between three insufficiently separated models of steel structures on structural response under earthquake excitation. The experimental tests as well as numerical analyses have been conducted in the study.

scholarly journals A Passive Rotary System for Seismic Risk Mitigation of Steel Structures

2014 ◽  
Vol 2 (2) ◽  
pp. 72 ◽  
Author(s):  
Ricky Chan ◽  
Peter Wong
Keyword(s):  
Earthquake Engineering ◽  
Risk Mitigation ◽  
Steel Structures ◽  
Earthquake Risk ◽  
Earthquake Excitation ◽  
Ground Shaking ◽  
Floor Slabs ◽  
Seismic Risk Mitigation ◽  
Displacement Based ◽  
Bracing System

This paper presents a novel bracing system designed for earthquake risk mitigation for steel structures. It involves a rotary system which a Chebyshev linkage connected to the ground and the building frame. Upon earthquake excitation, movement of structure floor slabs causes a rotational motion in the disc. Displacement-based dampers are installed between the rotary system and the ground which damp the structural vibrations. The system amplifies the travel of the dampers and efficiency is enhanced. In addition, the cross-brace members are always in tension, permitting the use of very slender sections. The paper first reviews the governing equations of the system, followed by a physical model demonstration. A 3-degree-of-system model with the proposed rotary system was subjected to simulated ground shaking. Acceleration on top floor was measured. Results demonstrated that proposed system effectively supresses the vibrational characteristics of the structure, and represents a viable and inexpensive solution to mitigate seismic risks.Keywords: Earthquake engineering, passive energy dissipation

scholarly journals Numerical Investigation on the CFRP Strengthened Steel Frame under Earthquake

2020 ◽  
Vol 995 ◽  
pp. 123-129
Author(s):  
T. Tafsirojjaman ◽  
Sabrina Fawzia ◽  
David Thambiratnam
Keyword(s):  
Seismic Performance ◽  
Steel Structure ◽  
Steel Structures ◽  
Steel Frame ◽  
Earthquake Excitation ◽  
Carbon Fibre Reinforced Polymer ◽  
Earthquake Load ◽  
Bare Steel ◽  
Real Earthquake ◽  
Normal Thickness

Steel structures are commonly used in seismic regions of the world because of its strength and ductility. However, these structures are still prone to damage during an earthquake. With this risk of seismic damage, the strengthening of steel structures is a major concern in order to resist the dynamic loads resulted from earthquakes. This report investigates the potential for the use of Carbon Fibre Reinforced Polymer (CFRP) to strengthen the rigid steel frame under a real earthquake load. This research will be undertaken using Strand7, a finite element (FE) analysis software. To validate the accuracy of this research, the finite analysis results have been compared to the available experimental study by the Authors. First, both FE models of a five-story bare steel frame and CFRP strengthened steel frame has been developed. Then the predicted numerical results of bare steel frame and CFRP strengthened steel frame under earthquake excitation are compared. The results indicated an increase in the seismic performance of the steel structure due to the strengthened with CFRP. The CFRP strengthened steel frame showed 15% less tip deflection compared to bare steel frame. Further analysis on the strengthening capabilities of higher thickness CFRP was performed to assess the effect of the thickness of CFRP and the higher thickness CFRP showed better seismic performance compare to normal thickness CFRP by reducing 34.38% of tip deflection.

CAD Of Anticorrosive Protection Of Steel Structures

2019 ◽  
pp. 18-23
Keyword(s):  
Protective Coating ◽  
Computer Aided Design ◽  
Steel Structures ◽  
Cost Effective ◽  
Operating Conditions ◽  
Computational Tool ◽  
Protection Method ◽  
Cost Effective Method ◽  
The Cost ◽  
Aided Design

The choice of cost-effective method of anticorrosive protection of steel structures is an urgent and time consuming task, considering the significant number of protection ways, differing from each other in the complex of technological, physical, chemical and economic characteristics. To reduce the complexity of solving this problem, the author proposes a computational tool that can be considered as a subsystem of computer-aided design and used at the stage of variant and detailed design of steel structures. As a criterion of the effectiveness of the anti-corrosion protection method, the cost of the protective coating during the service life is accepted. The analysis of existing methods of steel protection against corrosion is performed, the possibility of their use for the protection of the most common steel structures is established, as well as the estimated period of effective operation of the coating. The developed computational tool makes it possible to choose the best method of protection of steel structures against corrosion, taking into account the operating conditions of the protected structure and the possibility of using a protective coating.

Technology for Anticorrosive Protection of Steel Structures by Coatings Based on Rapid-Setting Bitumen-Latex Emulsion

2016 ◽  
Vol 12 (1) ◽  
pp. 28-35
Author(s):  
H.M. Nykyforchyn ◽  
◽  
V.A. Chervatyuk ◽  
V.I. Marukha ◽  
Z.V. Slobodyan ◽  
...  
Keyword(s):  
Steel Structures ◽  
Rapid Setting
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