scholarly journals Statics and Kinematics in Cyclic Behaviour of Semi-Rigid Steel Structures

2016 ◽  
Vol 6 (2) ◽  
pp. 25-32
Author(s):  
Corina - Ana Moldovan
Keyword(s):  
Constitutive Relation ◽  
Steel Structures ◽  
Numerical Results ◽  
The Other ◽  
Base Shear ◽  
Seismic Behaviour ◽  
End Plate ◽  
Cyclic Behaviour ◽  
Lateral Displacements ◽  
Seismic Forces

Abstract The contribution presents a set of seismic analyses of multi - storey steel structures with semi-rigid beam column connections acted upon by seismic actions. Semi-rigidity of the structures beam to column connections is conferred by two types of beam to column connections: top and seat and web angle (TSW) and end-plate (EP) joints. Computed numerical results are associated to two classes (static and kinematic) of seismic behaviour parameters expressing the two contradictory effects of semi-rigidity. On one hand, the lateral flexibility induces larger lateral displacements while, on the other hand, it attracts smaller base shear seismic forces. Also, the constitutive relation M − θr induced into semi- rigid beam column connections by seismic actions is presented. The results are presented in their numerical form and in a comparative graphical manner allowing for relevant comments and conclusions

scholarly journals Investigating the Effect of Viscous Damper on Seismic Behavior of Steel Dual Frames with Divergent Bracing Affected by Near and Far Fields Earthquake to Fault

2017 ◽  
Vol 3 (7) ◽  
pp. 526-536 ◽  
Author(s):  
Hamid Reza Ashrafi ◽  
Mozafar Shokri Rad ◽  
Yahya Adineh Far ◽  
Peyman Beiranvand ◽  
Soroush Dadgar
Keyword(s):  
Seismic Behavior ◽  
Time History ◽  
Base Shear ◽  
Dual Systems ◽  
Viscous Dampers ◽  
Seismic Behaviour ◽  
Non Linear ◽  
Waste Energy ◽  
Lateral Displacements ◽  
3D Software

Current study is sought to study the effect of linear and nonlinear liquid viscous dampers on steel frames having dual systems of bending frame and divergent bracing. These frames were first designed according to regulations of Iran’s 2800 standard and tenth chapter of national regulations of construction (planning and performing steel construction) through equivalent static method then frames were modelled again in non-linear analysis software and time history non-linear analyses were done on them with installing viscous dampers on these frames using recorded near and far faults. In this study the effect of viscous dampers will be investigated on seismic behaviour of mentioned frames and results will be proposed in form of maximum graphs of relative displacements, stories lateral displacements, base shear maximum, waste energy graphs and dampers’ force-displacements. All non-linear analyses have been done in PERFORM-3D software.

scholarly journals Evaluation of timber floor in-plane retrofitting interventions on the seismic response of masonry structures by DEM analysis: a case study

2021 ◽  
Author(s):  
Alessandra Gubana ◽  
Massimo Melotto
Keyword(s):  
Seismic Response ◽  
Masonry Wall ◽  
Masonry Building ◽  
Masonry Structures ◽  
Seismic Behaviour ◽  
Cyclic Behaviour ◽  
Out Of Plane ◽  
Dem Analysis ◽  
Side Walls ◽  
Seismic Forces

Abstract The seismic response of existing masonry structures is strongly influenced by floor and roof in-plane properties. An in-plane strengthening intervention is often needed on traditional timber floors to overcome their low in-plane stiffness and to preserve historical buildings. In this study, the effect of un-stiffened and stiffened timber floors on the seismic behaviour of an existing listed masonry building is investigated with dynamic non-linear analyses by means of the Discrete Element Method (DEM). With this approach, the failure processes and collapse sequences of masonry structures can be followed in detail. A previously developed model of the floor cyclic behaviour, based on experimental data, is here applied in the DEM models of the masonry building. Different seismic ground accelerations, different floor types and different wall-to-diaphragm connections are considered. The results highlight the effectiveness of the analysed floor strengthening solution in reducing the out-of-plane displacements of masonry walls. With adequate connections, the reinforced floor is able to transfer the seismic forces to the shear resistant walls up to the shear-sliding collapse of the side walls of the structure. A comparison with the ideal rigid diaphragm case confirms the good performance of the strengthened floors. The small observed out-of-plane displacements are compatible with the masonry wall capacity, and the reinforced floor hysteretic cycles contribute to dissipating part of the input energy. Moreover, different designs of the connections can also cap the transferred seismic forces to an acceptable level for seismic resistant walls.

scholarly journals Evaluation of timber floor in-plane retrofitting interventions on the seismic response of masonry structures by DEM analysis: a case study

2021 ◽  
Author(s):  
Alessandra Gubana ◽  
Massimo Melotto
Keyword(s):  
Seismic Response ◽  
Masonry Wall ◽  
Masonry Building ◽  
Masonry Structures ◽  
Seismic Behaviour ◽  
Cyclic Behaviour ◽  
Out Of Plane ◽  
Dem Analysis ◽  
Seismic Forces

AbstractThe seismic response of existing masonry structures is strongly influenced by floor and roof in-plane properties. A strengthening intervention is often needed for traditional timber floors to overcome their low in-plane stiffness and to preserve historical buildings. In this study, the effects of unreinforced and reinforced timber floors on the seismic behaviour of an existing listed masonry building are investigated with dynamic non-linear analyses by means of the Discrete Element Method (DEM). With this approach, the failure processes and collapse sequences of masonry structures can be captured in detail. A previously developed model of the floor cyclic behaviour, based on experimental data, is applied herein to DEM models of the masonry building. Different seismic ground accelerations, different floor types and different floor-to-wall connections are considered. The results highlight the effectiveness of the analysed floor strengthening solution in reducing the out-of-plane displacements of masonry walls. With adequate connections, the reinforced floor is able to transfer the seismic forces to the shear-resistant walls up to the shear-sliding collapse of the structural sidewalls. A comparison with the ideal rigid diaphragm case confirms the good performance of the strengthened floors. The small observed out-of-plane displacements are compatible with the masonry wall capacity, and the reinforced floor hysteretic cycles contribute to dissipate part of the input energy. Moreover, different designs of the connections can also cap the transferred seismic forces to an acceptable level for shear-resistant walls.

Observations Regarding Numerical Results Obtained by the Floquet-Method

2013 ◽  
Author(s):  
Till J. Kniffka ◽  
Horst Ecker
Keyword(s):  
Numerical Methods ◽  
Monodromy Matrix ◽  
Mathieu Equation ◽  
Numerical Results ◽  
The Other ◽  
Benchmark Problem ◽  
Stability Studies ◽  
Floquet Method ◽  
System Equations ◽  
Time Periodic

Stability studies of parametrically excited systems are frequently carried out by numerical methods. Especially for LTP-systems, several such methods are known and in practical use. This study investigates and compares two methods that are both based on Floquet’s theorem. As an introductary benchmark problem a 1-dof system is employed, which is basically a mechanical representation of the damped Mathieu-equation. The second problem to be studied in this contribution is a time-periodic 2-dof vibrational system. The system equations are transformed into a modal representation to facilitate the application and interpretation of the results obtained by different methods. Both numerical methods are similar in the sense that a monodromy matrix for the LTP-system is calculated numerically. However, one method uses the period of the parametric excitation as the interval for establishing that matrix. The other method is based on the period of the solution, which is not known exactly. Numerical results are computed by both methods and compared in order to work out how they can be applied efficiently.

scholarly journals Seismic Behavior of RC Buildings with Effect of Staircase and Elevator Core Wall

2019 ◽  
Vol 8 (4) ◽  
pp. 3821-3826
Keyword(s):  
Response Spectrum ◽  
Vital Role ◽  
Base Shear ◽  
Rc Buildings ◽  
Opposite Edge ◽  
Seismic Behaviour ◽  
Response Spectrum Analysis ◽  
Building Model ◽  
Opposite Position ◽  
Better Than

Staircase and elevator are the main structural components in multi-story buildings to enable access to different floor levels. In many Multi-storey buildings staircase and elevator core wall are located at different positions as per the benefits of structure plan and user. The position of the staircase and elevator core wall plays a vital role and changing the position of the stair case and core wall leads torsional irregularity in the plan regular building. The torsion in a building occurs because of eccentricity in the mass and stiffness distributions. The staircase and core wall is an integral part of the building, and its position may change the dynamic characteristic of regular plan building. In this paper, an attempt is made to understand the seismic behaviour of RC buildings with the effect of staircase and elevator core wall with changing position. Six models of 5 storey RC buildings with different positions of staircase and elevator core wall, i.e. ideal frame, Centre, Corner, Edge-Opposite, Edge-Adjacent and Corner with cantilever or balcony are considered. The modelling and analysis is done using ETABS v17. The response spectrum analysis and Modal analysis is performed, and Results of storey displacements, storey drift, storey shear, storey stiffness, base shear and torsion irregularity are discussed. From the results, it can be observed that building model with an edge-opposite position of staircase and elevator core wall performs better than other building model and torsion for it came within the code suggested ratio of 1.2.

scholarly journals A Simplified Method for the Design of Steel Beam-to-column Connections

2017 ◽  
Vol 48 (2) ◽  
pp. 79-86
Author(s):  
Imola Kristóf ◽  
Zsanett Novák ◽  
Dezső Hegyi
Keyword(s):  
Failure Modes ◽  
Steel Structures ◽  
Simple Calculation ◽  
Geometric Parameters ◽  
End Plate ◽  
Simplified Method ◽  
Eurocode 3 ◽  
Steel Sections ◽  
The Moment ◽  
Hot Rolled

The moment resistance of beam-to-column connections is frequently utilised in steel structures. Eurocode 3 suggests the component method to analyse such connections, and it implements the equivalent T-stub method to determine the resistance of the end plate of the beam. The latter method requires tedious and concentrated work. A simplified method is suggested to reduce the number of calculations and enable the designer to focus on construction aspects in the pre-design phase, or in education.The resistance of the T-stub covers three possible failure modes: the yield of the plate, the failure of the of the bolt and simultaneous yield. The yield of the plate and simultaneous yield depend on numerous parameters, and they are verified by multiple equations. The failure of the bolts are more easily checked.In the present paper, requirements for geometric ratios are defined for the widely used steel sections to assure failure of the bolts at a lower level of the load than the yield of the plate. These parameters facilitate the simple calculation of the resistance of the bolts instead of the tedious work needed for the end plate resistance.The paper presents a proper explanation for the design rules and the effect of the geometric parameters on the resistance of the end plate. Geometric parameters are suggested for the widely used hot rolled and typical welded beam sections. All the parameters fulfil the requirements of the equivalent T-stub method of Eurocode 3.

Nonlinear Cyclic Behaviour of Precast Concrete Frame Sub-Assemblies With “Dry” End Plate Connection

Structures ◽  
2018 ◽  
Vol 14 ◽  
pp. 124-136 ◽  
Author(s):  
P.K. Aninthaneni ◽  
R.P. Dhakal ◽  
J. Marshall ◽  
J. Bothara
Keyword(s):  
Precast Concrete ◽  
Concrete Frame ◽  
End Plate ◽  
Cyclic Behaviour ◽  
Plate Connection

Numerical Simulation on the Electrophoretic Motion of Multiple Particles in Microchannels

2004 ◽  
Author(s):  
Chunzhen Ye ◽  
Dongqing Li
Keyword(s):  
Numerical Simulation ◽  
Flow Field ◽  
Electric Field ◽  
Particle Motion ◽  
Outer Region ◽  
Numerical Results ◽  
The Other ◽  
Double Layers ◽  
Rectangular Microchannel ◽  
Moving Particle

This paper considers the electrophoretic motion of multiple spheres in an aqueous electrolyte solution in a straight rectangular microchannel, where the size of the channel is close to that of the particles. This is a complicated 3-D transient process where the electric field, the flow field and the particle motion are coupled together. The objective is to numerically investigate how one particle influences the electric field and the flow field surrounding the other particle and the particle moving velocity. It is also aimed to investigate and demonstrate that the effects of particle size and electrokinetic properties on particle moving velocity. Under the assumption of thin electrical double layers, the electroosmotic flow velocity is used to describe the flow in the inner region. The model governing the electric field and the flow field in the outer region and the particle motion is developed. A direct numerical simulation method using the finite element method is adopted to solve the model. The numerical results show that the presence of one particle influences the electric field and the flow field adjacent to the other particle and the particle motion, and that this influences weaken when the separation distance becomes bigger. The particle motion is dependent on its size, with the smaller particle moving a little faster. In addition, the zeta potential of particle has an effective influence on the particle motion. For a faster particle moving from behind a slower one, numerical results show that the faster moving particle will climb and then pass the slower moving particle then two particles’ centers are not located on a line parallel to the electric field.

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