An Analytical Mechanical Model for the Seismic Assessment of Bell Towers

2014 ◽  
Vol 624 ◽  
pp. 97-105
Author(s):  
Sergio Lagomarsino ◽  
Daria Ottonelli ◽  
Serena Cattari
Keyword(s):  
Seismic Response ◽  
Mechanical Model ◽  
Main Body ◽  
Seismic Action ◽  
3D Fem ◽  
Fem Model ◽  
Bell Tower ◽  
Preliminary Validation ◽  
Proposed Model ◽  
Displacement Based

The paper describes the analytical model, recently proposed in the Perpetuate Project, aimed to assess the seismic response of the shaft of bell towers, of which the vulnerability to the seismic action has been dramatically testified also by the recent events (as that which hit L’Emilia region in 2012). As main novelties, the model follows the Displacement Based Approach (DBA) for the seismic verification and catches both the shear and combined bending and compression response of the main body of bell towers. In order to clarify the application and to provide a preliminary validation of the proposed model, the seismic response of the bell tower of the San Carlo Church in Castellazzo Bormida (Al, Italy) has been studied. It includes also a detailed analysis on a 3D FEM model aimed to support the calibration of some parameters which the model is founded on in case of quite irregular bell towers characterized by non symmetric boundary conditions that can significantly affect their dynamic behavior, as the case analyzed.

THE EFFECTS ON SHAPE-MODELING OF CONCRETE GRAVITY DAMS IN EARTHQUAKE RESPONSE ANALYSES

2015 ◽  
Vol 2 (1) ◽  
Author(s):  
Tatsuo Nishiuchi
Keyword(s):  
Seismic Response ◽  
High Elevation ◽  
Earthquake Response ◽  
Basement Rock ◽  
Gravity Dams ◽  
3D Fem ◽  
Fem Model ◽  
Concrete Gravity Dams ◽  
Contraction Joints ◽  
Non Linear

To clarify the effects of seismic response of concrete gravity dams under large earthquake, finite element method (FEM) analyses were carried out. In analyses, the height of dam and material properties of concrete and basement rock are same. The 2-dimensional (2D) and the 3-dimensional (3D) FEM model were made and used in earthquake response analyses. The contraction joints between dam block are concerned in 3D non-linear FEM analysis. In the case of same height of dam, the numerical results of damage states and placements in dam are different between 2D FEM model and 3D FEM model, due to the effect of difference in vibration mode of dam. In the 2D FEM model, the damage of top in cross-section becomes remarkable. In the 3D FEM model, the damage of attachment between dam body and basement rock at high-elevation becomes remarkable. The damage of 3D FEM model is smaller than that of 2D FEM model for the same acceleration level of earthquake. The influence of seismic response on contraction joints of 3D non-linear FEM dam model is smaller, which is as same as that of 3D linear FEM dam model. From the above results, the 2D FEM model gives a conservative assessment compared to the 3D FEM model.

Seismic Response Analysis of Tower Crane in Consideration of the Building-Crane Interaction

2013 ◽  
Vol 353-356 ◽  
pp. 1981-1985 ◽  
Author(s):  
Bing Ai ◽  
Jia Lin Yang ◽  
Zeng Zhuang Pei
Keyword(s):  
Seismic Response ◽  
Seismic Analysis ◽  
Dynamic Responses ◽  
Response Analysis ◽  
Analysis Method ◽  
Ansys Software ◽  
Seismic Response Analysis ◽  
3D Fem ◽  
Fem Model ◽  
Tower Crane

Interaction between buildings and tower has not been considered in former research..In this paper an integrated seismic analysis method is proposed considering the interaction between the building and the tower crane. A 3D-FEM model of the building and the crane is established with ANSYS software and seismic responses such as the displacement, the acceleration and the stress of the crane are analyzed. The sensitivity of the stiffness of the building on the dynamic responses is also analyzed. The results with consideration of the building-crane interaction, is higher than the results without interaction, and it becomes more significant with the increase of stiffness of the building.

FINE-TUNING OF MODELLING STRATEGY TO SIMULATE THERMO-MECHANICAL BEHAVIOUR OF DOUBLE FRICTION PENDULUM SEISMIC ISOLATORS UST ESTIMATOR

2019 ◽  
Vol 3 (Special Issue on First SACEE'19) ◽  
pp. 165-172
Author(s):  
Vincenzo Bianco ◽  
Giorgio Monti ◽  
Nicola Pio Belfiore
Keyword(s):  
Multibody Dynamics ◽  
Mechanical Behaviour ◽  
Mechanical Model ◽  
Dynamic Behaviour ◽  
Experimental Testing ◽  
Fine Tuning ◽  
Proposed Model ◽  
Modelling Techniques ◽  
Friction Pendulum

The use of friction pendulum devices has recently attracted the attention of both academic and professional engineers for the protection of structures in seismic areas. Although the effectiveness of these has been shown by the experimental testing carried out worldwide, many aspects still need to be investigated for further improvement and optimisation. A thermo-mechanical model of a double friction pendulum device (based on the most recent modelling techniques adopted in multibody dynamics) is presented in this paper. The proposed model is based on the observation that sliding may not take place as ideally as is indicated in the literature. On the contrary, the fulfilment of geometrical compatibility between the constitutive bodies (during an earthquake) suggests a very peculiar dynamic behaviour composed of a continuous alternation of sticking and slipping phases. The thermo-mechanical model of a double friction pendulum device (based on the most recent modelling techniques adopted in multibody dynamics) is presented. The process of fine-tuning of the selected modelling strategy (available to date) is also described.

scholarly journals Improved Modeling of a Multi-Level Inverter for TACS to Reduce Computational Time and Improve Accuracy

Energies ◽  
2021 ◽  
Vol 14 (4) ◽  
pp. 849
Author(s):  
Sung-An Kim
Keyword(s):  
Mechanical Model ◽  
Simulation Software ◽  
Computational Time ◽  
Electrical Model ◽  
Conventional Model ◽  
Switching Operation ◽  
Air Compressor ◽  
Power Semiconductors ◽  
Proposed Model ◽  
Multi Level

A modeling of a turbo air compressor system (TACS), with a multi-level inverter for driving variable speed, combining an electrical model of an electric motor drive system (EMDS) and a mechanical model of a turbo air compressor, is essential to accurately analyze dynamics characteristics. Compared to the mechanical model, the electrical model has a short sampling time due to the high frequency switching operation of the numerous power semiconductors inside the multi-level inverter. This causes the problem of increased computational time for dynamic characteristics analysis of TACS. To solve this problem, the conventional model of the multi-level inverter has been proposed to simplify the switching operation of the power semiconductors, however it has low accuracy because it does not consider pulse width modulation (PWM) operation. Therefore, this paper proposes an improved modeling of the multi-level inverter for TACS to reduce computational time and improve the accuracy of electrical and mechanical responses. In order to verify the reduced computational time of the proposed model, the conventional model using the simplified model is compared and analyzed using an electronic circuit simulation software PSIM. Then, the improved accuracy of the proposed model is verified by comparison with the experimental results.

scholarly journals Near-Fault Seismic Response Analysis of Bridges Considering Girder Impact and Pier Size

Mathematics ◽  
2021 ◽  
Vol 9 (7) ◽  
pp. 704
Author(s):  
Wenjun An ◽  
Guquan Song ◽  
Shutong Chen
Keyword(s):  
Seismic Response ◽  
Bending Moment ◽  
Expansion Method ◽  
Response Analysis ◽  
Seismic Action ◽  
Transient Wave ◽  
Cross Sectional ◽  
Displacement Response ◽  
Near Fault ◽  
Continuous Girder Bridge

Given the influence of near-fault vertical seismic action, we established a girder-spring-damping-rod model of a double-span continuous girder bridge and used the transient wave function expansion method and indirect modal function method to calculate the seismic response of the bridge. We deduced the theoretical solution for the vertical and longitudinal contact force and displacement response of the bridge structure under the action of the near-fault vertical seismic excitation, and we analyzed the influence of the vertical separation of the bridge on the bending failure of the pier. Our results show that under the action of a near-fault vertical earthquake, pier-girder separation will significantly alter the bridge’s longitudinal displacement response, and that neglecting this separation may lead to the underestimation of the pier’s bending damage. Calculations of the bending moment at the bottom of the pier under different pier heights and cross-sectional diameters showed that the separation of the pier and the girder increases the bending moment at the pier’s base. Therefore, the reasonable design of the pier size and tensile support bearing in near-fault areas may help to reduce longitudinal damage to bridges.

3D FEM model to simulate Brownian motion inside trabecular tissue from human femoral head

2021 ◽  
pp. 1-8
Author(s):  
Fabiano Bini ◽  
Andrada Pica ◽  
Simone Novelli ◽  
Raffaella Pecci ◽  
Rossella Bedini ◽  
...  
Keyword(s):  
Brownian Motion ◽  
Femoral Head ◽  
3D Fem ◽  
Fem Model

scholarly journals Seismic rocking effects on a mine tower under induced and natural earthquakes

2021 ◽  
Vol 21 (2) ◽  
Author(s):  
Piotr Adam Bońkowski ◽  
Juliusz Kuś ◽  
Zbigniew Zembaty
Keyword(s):  
Seismic Response ◽  
Ground Motion ◽  
Ground Surface ◽  
Tall Buildings ◽  
Earthquake Ground Motion ◽  
Seismic Action ◽  
Seismic Effects ◽  
Copper Ore ◽  
Rotational Components ◽  
Natural Earthquakes

AbstractRecent research in engineering seismology demonstrated that in addition to three translational seismic excitations along x, y and z axes, one should also consider rotational components about these axes when calculating design seismic loads for structures. The objective of this paper is to present the results of a seismic response numerical analysis of a mine tower (also called in the literature a headframe or a pit frame). These structures are used in deep mining on the ground surface to hoist output (e.g. copper ore or coal). The mine towers belong to the tall, slender structures, for which rocking excitations may be important. In the numerical example, a typical steel headframe 64 m high is analysed under two records of simultaneous rocking and horizontal seismic action of an induced mine shock and a natural earthquake. As a result, a complicated interaction of rocking seismic effects with horizontal excitations is observed. The contribution of the rocking component may sometimes reduce the overall seismic response, but in most cases, it substantially increases the seismic response of the analysed headframe. It is concluded that in the analysed case of the 64 m mining tower, the seismic response, including the rocking ground motion effects, may increase up to 31% (for natural earthquake ground motion) or even up to 135% (for mining-induced, rockburst seismic effects). This means that not only in the case of the design of very tall buildings or industrial chimneys but also for specific yet very common structures like mine towers, including the rotational seismic effects may play an important role.

scholarly journals Influence of end Contsrains on the Global Behaviour of a Box Girder

2016 ◽  
Vol 6 (1) ◽  
pp. 7-15
Author(s):  
Daniela Mihaela Boca ◽  
A. Faur ◽  
A. Boca
Keyword(s):  
Prestressed Concrete ◽  
Transport Infrastructure ◽  
Box Girders ◽  
3D Fem ◽  
Important Data ◽  
Box Girder ◽  
Fem Model ◽  
Global Behaviour ◽  
Applied Forces ◽  
Precast Prestressed Concrete

Abstract This study aims to presents the importance of end constrains, boundary conditions and position of the applied forces regarding the design of precast/prestressed concrete box girders. The study is based on a destructive test which was performed on a 37.1 m span single-cell prestressed concrete box girder. The scope of the test was to certify the usage of such girders for the new Transylvania motorway bridges. The test is numerically reproduced through a full 3D FEM model implemented in SAP2000. The influence of the end diaphragms is considered by analysing the beam’s behaviour to six loading conditions: one of which is replicating the loadings during the test, while the others are conceived as real vertical and horizontally loading scenarios. The results obtained for the girders with and without end constrains are compared. The performances of both design solutions in the presence of prestressing are highlighted where applicable. It is considered that the results of this study may provide very important data if considering that Romania has an urgent need to realize a modern and an adequate transport infrastructure.

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