scholarly journals A constant friction coefficient model for concave friction bearings

2020 ◽  
Vol 14 (1) ◽  
pp. 112-126
Author(s):  
Dao Dinh Nhan ◽  
Chung Bac Ai
Keyword(s):  
Friction Coefficient ◽  
Numerical Models ◽  
Structural Response ◽  
Time History ◽  
Friction Model ◽  
System Response ◽  
Isolation System ◽  
Constant Friction ◽  
Friction Pendulum ◽  
Friction Bearings

This paper develops a constant friction coefficient model that best represents a velocity-dependent friction model for predicting structural response of buildings isolated with concave friction bearings. To achieve this goal, the effect of friction model on structural response of three hypothetical isolated buildings with different number of stories subjected to different earthquake scenarios was numerically investigated. The structural numerical models of the isolated buildings were developed in OpenSees with superstructure is represented by a shear frame model and isolation system using single friction pendulum bearings is modeled by a 3-D friction pendulum bearing element which accepts different friction models. The numerical models were subjected to 30 pairs of ground motions, representing service earthquake level, design basic earthquake level and maximum considered earthquake level at a strong seismic activity area in the world. The investigation reveals that friction coefficient models significantly affect the structural response and there is no constant friction coefficient model that simultaneously best predicts isolation system response and superstructure response. The constant friction coefficient that best predicts isolation system response produces a large error on prediction of superstructure response and vice versa. Based on the numerical results, a constant friction coefficient model for different criteria was developed. Keywords: friction coefficient model; friction bearing; isolation system; earthquake response; time-history analysis.

scholarly journals The effect of seismic base isolation on structural response of a 12-story hotel building in Padang, Indonesia

2020 ◽  
Vol 156 ◽  
pp. 05026
Author(s):  
Fauzan ◽  
Afdhalul Ihsan ◽  
Mutia Putri Monika ◽  
Zev Al Jauhari
Keyword(s):  
Base Isolation ◽  
Response Spectrum ◽  
Soft Soil ◽  
Structural Response ◽  
Time History ◽  
Seismic Zone ◽  
Isolation System ◽  
Rubber Bearing ◽  
Seismic Base Isolation ◽  
The City

The amount of potential investment in Padang City, Indonesia since 2017 attracted many investors to contribute to the city. One of the investments is a 12-story hotel that will be constructed in By Pass Street of the city. The hotel is located in a high seismic zone area, so the seismic base isolation has been proposed to be used in the hotel building. The main aim of using a seismic base isolation device is to reduce the inertia forces introduced in the structure due to earthquakes by shifting the fundamental period of the structure out of dangerous resonance range and concentration of the deformation demand at the isolation system. An analytical study on the Reinforced Concrete (RC) hotel building with and without rubber bearing (RB) base isolation is carried out using the response spectrum and time history analysis methods. The results show that internal forces and inter-story drift of the building with high damping rubber bearing (HDRB) are lower than that of the fixed base with a remarkable margin. From this study, it is recommended to use the HDRB base isolation for medium and high rise buildings with soft soil in Padang City, Indonesia.

Modelling the response of structure-tuned liquid damper systems under large amplitude excitation using SPH

2021 ◽  
pp. 1-31
Author(s):  
Kevin P. McNamara ◽  
Michael J. Tait
Keyword(s):  
Experimental Data ◽  
Large Amplitude ◽  
Numerical Models ◽  
Model Performance ◽  
Structural Response ◽  
System Response ◽  
Tuned Liquid Damper ◽  
Tall Structures ◽  
Incompressible Sph ◽  
Lower Excitation

Abstract The tuned liquid damper (TLD) is a system used to reduce the response of tall structures. Numerical modelling is a very important tool when designing TLDs. Many existing numerical models are capable of accurately capturing the structure-TLD system response at serviceability levels, covering the range where TLDs are primarily intended to perform. However, these models often have convergence issues when considering more extreme structural excitations. The goal of this study is to develop a structure-TLD model without convergence limitations at large amplitude excitations. A structure-TLD numerical model where the TLD is represented by a 2D incompressible SPH scheme is presented. The TLD contains damping screens which are represented by a force term based on the Morison equation. The performance of the model is assessed by comparing to experimental data for a structure-TLD system undergoing large amplitude excitations consisting of four-hour random signals and shorter transient signals. The model shows very good agreement with the experimental data for the structural response. The free surface response of the TLD is captured accurately by the model for the lower excitation forces considered, however as the excitation force is increased there are some discrepancies. The large amplitude excitations also result in SPH fluid particles penetrating the boundaries, resulting in degradation of the model performance over the four-hour simulations. Overall, the model is shown to capture the response of a structure-TLD system undergoing large amplitude excitations well.

Seismic Isolation Retrofit of an Office Building Using Friction Pendulum System

2014 ◽  
Vol 578-579 ◽  
pp. 1361-1365
Author(s):  
Lin Liu ◽  
Xuan Min Li ◽  
Wei Tian
Keyword(s):  
Seismic Isolation ◽  
Base Isolation ◽  
Time History ◽  
Nonlinear Behavior ◽  
Office Building ◽  
Nonlinear Time History Analysis ◽  
Isolation System ◽  
Pendulum System ◽  
Nonlinear Time History ◽  
Friction Pendulum

Friction Pendulum Systems have been used as base isolation systems for both new construction and retrofit around the world. This paper presented its implementation in an office building located in Shanghai. To evaluate its impact on seismic performance of the retrofitted structure, models are needed to capture the intricate nonlinear behavior of both structural components and isolator elements. Nonlinear time history analysis of the building for the original and retrofitted cases was conducted to assess the efficiency of the isolation system at the high earthquake level. The numerical results indicate that the retrofitted structure experiences significantly less damage and less deformation due to the shake isolation and energy dissipation through the isolators.

scholarly journals Energy Response Analysis of Continuous Beam Bridges with Friction Pendulum Bearing by Multihazard Source Excitations

2020 ◽  
Vol 2020 ◽  
pp. 1-17
Author(s):  
Bing Li ◽  
Bin Wang ◽  
Shaohua Wang ◽  
Xiao Wu
Keyword(s):  
Finite Element ◽  
Friction Coefficient ◽  
Structural Response ◽  
Analytical Modelling ◽  
Continuous Beam ◽  
Energy Response ◽  
Isolated Bridge ◽  
Friction Pendulum ◽  
Isolated Bridges ◽  
Isolation Period

Based on the principle of conservation of energy, analytical modelling of the energy response of continuous beam bridges with friction pendulum bearing (FPB) was carried out for foundation-induced vibrations. A three-dimensional finite element analysis of a multispan continuous concrete girder bridge with FPB was established using the nonlinear time-history method to verify the accuracy of analytical modelling. The influence of the friction coefficient and isolation period of the FPB on the energy response of isolated bridge was then investigated under multihazard source excitations (e.g., El Centro and Taft waves) with different dominant periods and durations. The variations of structural response energy, sliding displacement, energy dissipation ratio, and acceleration of the isolated bridges are plotted. The results of analytical modelling and finite element simulation show good agreement. In addition, there exist particular values of the friction coefficient and isolation period of FPB, for which the structural response energy of the isolated bridges attains the minimum value. The optimal parameters of FPB are greatly influenced by seismic waves, and the friction coefficient of FPB should be increased with the increase of seismic fortification intensity. In addition, the energy dissipation capacity of FPB used in isolated bridge is excellent.

scholarly journals Seismic Isolation System using U-Shaped Steel Damper

2019 ◽  
Vol 8 (4) ◽  
pp. 12336-12339
Keyword(s):  
Seismic Isolation ◽  
Base Isolation ◽  
Structural Response ◽  
Time History ◽  
Earthquake Ground Motion ◽  
Isolation System ◽  
Isolation Technique ◽  
Base Isolation System ◽  
The Time Domain ◽  
External Forces

In the present paper base isolation system is analyzed and its seismic behavior is investigated using U-shaped steel dampers as an isolator by placing it at the bottom of the structure. It is the most popular way of protecting the structure using control techniques for earthquake ground motion. The dampers significantly reduced damage factors such as displacement and drift. To reduce structural response to external forces, which can be accomplished through the use of special protective systems. So to prevent these damages, seismic isolation technique can be used for newly constructed structures. The time history analysis of the time domain on this structure is conducted by using SAP2000 software

scholarly journals Performance comparisons of triple friction pendulum bearings with different sliding surface properties

2021 ◽  
Vol 4 (3) ◽  
pp. 151-162
Author(s):  
Muhamad Zulfakar ◽  
Ali İhsan Karakaş
Keyword(s):  
Friction Coefficient ◽  
Surface Properties ◽  
Friction Surface ◽  
Time History ◽  
Radius Of Curvature ◽  
Sliding Surface ◽  
Base Shear ◽  
Finite Element Program ◽  
Element Program ◽  
Friction Pendulum

In this study the time history analyses are carried out three dimensionally for a simple five-story concrete structure seismically isolated incorporating triple friction pendulum bearings with different sliding surface properties with the help of the ABAQUS finite element program. The altering friction surface properties are friction coefficient and radius of curvature. The performances of the various isolators are compared with each other as well as with those of a fixed based structure. For this purpose, maximum relative story displacements, story accelerations and column base shear forces are investigated as seismic reactions. According to the analysis results it can be stated that the seismic reactions of isolated structures are significantly reduced when compared to those of the fixed supported structure. Additionally, when triple friction pendulum bearing isolators with different friction coefficients and friction surface radii are compared, it can be observed that increasing the friction coefficient increases the reactions of the structure while increasing the friction surface radii decreases the reactions

Research on Seismic Isolation Properties for DFPS System

2010 ◽  
Vol 163-167 ◽  
pp. 4342-4345
Author(s):  
Nan Ge ◽  
Hai Bin Chen ◽  
Xing Guo Wang
Keyword(s):  
Friction Coefficient ◽  
Seismic Isolation ◽  
Optimum Combination ◽  
Seismic Action ◽  
Isolation System ◽  
Pendulum System ◽  
Slipping Friction ◽  
Friction Plate ◽  
Friction Pendulum ◽  
Plate System

A theoretical analyzing approach about a novel seismic isolation system, DFPS (Double Slipping-Surfaced Friction Plate System), is presented in this paper. Its governing equation is similar to that of the FPS friction pendulum system with single slipping surface. It is shown that the inter-storey drift resulted from seismic action could be drastically decreased on buildings equipped with DFPS system. If an optimum combination of slide radius and slipping friction coefficient is adopted, the seismic isolation effectiveness could be as high as 90%.

scholarly journals Shaking table tests of a base isolated structure with Double Concave Friction Pendulum bearings

2015 ◽  
Vol 48 (2) ◽  
pp. 136-144 ◽  
Author(s):  
Felice C. Ponzo ◽  
Antonio D. Cesare ◽  
Gianmarco Leccese ◽  
Domenico Nigro
Keyword(s):  
Base Isolation ◽  
Experimental Testing ◽  
Design Procedure ◽  
Time History ◽  
Shaking Table ◽  
Shaking Table Tests ◽  
Isolation System ◽  
Sliding Surfaces ◽  
Residual Displacements ◽  
Friction Pendulum

An extensive experimental testing programme named JETBIS project (Joint Experimental Testing of Base Isolation Systems) was developed within the RELUIS II project (Task 2.3.2) and RELUIS III project (Line 6) involving partners from different Italian universities. This paper describes the seismic tests performed by the research unit of University of Basilicata (UNIBAS) on an isolation system based on Double Concave Friction Pendulum (DCFP) bearings. The DCFP bearing contains two separate concave sliding surfaces and exhibits different hysteretic properties at different stages of displacement response. The main objective of this work is to evaluate the horizontal response of the DCFP isolators by means of controlled-displacement tests and shaking table tests. The experimental model was a 1/3 scaled steel framed structure with one storey and one bay in both directions. Four DCFP bearings with equal properties of the sliding surfaces were considered. In this work, three different sliding surface conditions (with and without lubrication) have been studied. The isolated base model was subjected to 8 natural earthquakes of increasing seismic intensities and considering two mass configurations (with both symmetrical and eccentric masses). The reliability of the design procedure considered for the isolation system was verified also when relevant residual displacements occurred due to previous earthquakes. In this paper, the comparisons between the experimental outcomes and the numerical results of nonlinear time-history analyses using SAP2000 are shown.

Convergence Behaviors of Reduced-Order Models for Frictional Contacts

2003 ◽  
Author(s):  
D. Deshmukh ◽  
E. J. Berger
Keyword(s):  
Cyclic Loading ◽  
Numerical Models ◽  
Point Contact ◽  
Structural Response ◽  
System Response ◽  
Physical Parameters ◽  
Single Element ◽  
Interface Behavior ◽  
Frictional Contacts ◽  
Kinematic Behavior

Numerical models to simulate interface behavior of friction connections under cyclic loading are investigated. The question of validity of lower order models in successfully capturing response of friction joints under cyclic loading is addressed. Single-element macroslip models are not capable of capturing localized interface behavior prior to gross interfacial slip. This paper focuses the convergence behavior of a multi-point contact microslip model comprised of Iwan-type elements for different physical parameters such as system response amplitude and kinematic state of the friction joint. It is observed that system dynamics play a significant role in determining the convergence of frictional behavior, especially for tuned damper sets. This behavior is explored using simple linearized models. In addition, the interface kinematic behavior converges at a slower rate than the structural response and therefore requires a higher-order interface model.

scholarly journals Research on Hydroelastic Response of an FMRC Hexagon Enclosed Platform

Symmetry ◽  
2021 ◽  
Vol 13 (7) ◽  
pp. 1110
Author(s):  
Wei-Qin Liu ◽  
Luo-Nan Xiong ◽  
Guo-Wei Zhang ◽  
Meng Yang ◽  
Wei-Guo Wu ◽  
...  
Keyword(s):  
Time Domain ◽  
Numerical Models ◽  
Structural Response ◽  
Deep Ocean ◽  
Surface Model ◽  
Large Area ◽  
Floating Structure ◽  
Small Depth ◽  
Response Amplitude Operators ◽  
Hydroelastic Response

The numerical hydroelastic method is used to study the structural response of a hexagon enclosed platform (HEP) of flexible module rigid connector (FMRC) structure that can provide life accommodation, ship berthing and marine supply for ships sailing in the deep ocean. Six trapezoidal floating structures constitute the HEP structure so that it is a symmetrical very large floating structure (VLFS). The HEP has the characteristics of large area and small depth, so its hydroelastic response is significant. Therefore, this paper studies the structural responses of a hexagon enclosed platform of FMRC structure in waves by means of a 3D potential-flow hydroelastic method based on modal superposition. Numerical models, including the hydrodynamic model, wet surface model and finite element method (FEM) model, are established, a rigid connection is simulated by many-point-contraction (MPC) and the number of wave cases is determined. The load and structural response of HEP are obtained and analyzed in all wave cases, and frequency-domain hydroelastic calculation and time-domain hydroelastic calculation are carried out. After obtaining a number of response amplitude operators (RAOs) for stress and time-domain stress histories, the mechanism of the HEP structure is compared and analyzed. This study is used to guide engineering design for enclosed-type ocean platforms.

Sign in / Sign up

Export Citation Format

Share Document