scholarly journals Damage Analyses of Replaceable Links in Eccentrically Braced Frame (EBF) Subject to Cyclic Loading

2019 ◽  
Vol 9 (2) ◽  
pp. 332 ◽  
Author(s):  
Zhanzhong Yin ◽  
Dazhe Feng ◽  
Wenwei Yang
Keyword(s):  
Energy Dissipation ◽  
Cyclic Loading ◽  
Failure Modes ◽  
Rotation Angle ◽  
Experimental Studies ◽  
Hysteresis Curve ◽  
Cross Sectional ◽  
Braced Frame ◽  
Plastic Rotation ◽  
Cyclic Loading Tests

In the current design of steel eccentrically braced frames (EBFs), the yielding link is coupled with the floor beam. This causes the design of cross-sectional dimensions of links to be enlarged, resulting in over-designed structures and foundations, and increasing the cost of the overall structure. In addition, the beams are forecast to sustain severe damage through repeated inelastic deformations under design-level earthquakes, and thus the structure may require extensive repair or need to be replaced. To improve upon these drawbacks, a shear device with replaceable links based on EBFs was designed. The hysteresis curve, the stress distribution, and the deformation of the specimen were obtained by cyclic loading tests of the eight replaceable links. The energy dissipation behavior, the bearing capacity, the failure modes, and the plastic rotation angle of those specimens were analyzed. The results indicated clearly that the links in this shear device had inelastic deformation concentrated in the link showing very stable hysteresis behavior, and damaged links were replaced easily as end-plate connections were adopted. The energy dissipation capacity and the plastic rotation angle of the specimens were mainly dependent on the arrangement of stiffener, length ratio, and welding access holes. Experimental studies performed in this research and the related damage analyses reveal that cracks are the major causes of damage to the EBF and there is a lack of research on real-time monitoring of the onset and development of these cracks in EBF structures. As a future work, this paper proposes a piezoceramic patch transducer-based active sensing approach to monitor the crack onset and development of the EBF when subjected to dynamic loadings.

scholarly journals Low-Cyclic Loading Tests of Self-Centering Variable Friction (SCVF) Brace

2020 ◽  
Vol 2020 ◽  
pp. 1-13
Author(s):  
Qingguang He ◽  
Yanxia Bai ◽  
Weike Wu ◽  
Yongfeng Du
Keyword(s):  
Finite Element ◽  
Friction Coefficient ◽  
Energy Dissipation ◽  
Cyclic Loading ◽  
Variable Friction ◽  
Loading Tests ◽  
Low Cyclic Loading ◽  
Energy Dissipation System ◽  
Cyclic Loading Tests ◽  
Dissipation System

A novel assembled self-centering variable friction (SCVF) brace is proposed which is composed of an energy dissipation system, a self-centering system, and a set of force transmission devices. The hysteretic characteristics and energy dissipation of the SCVF brace with various parameters from low-cyclic loading tests are presented. A finite element model was constructed and tested under simulated examination for comparative analysis. The results indicate that the brace shows an atypical flag-type hysteresis curve. The SCVF brace showed its stable self-centering ability and dissipation energy capacity within the permitted axial deformation under different spring and friction plates. A larger deflection of the friction plate will make the variable friction of this SCVF brace more obvious. A higher friction coefficient will make the energy dissipation capacity of the SCVF brace stronger, but the actual friction coefficient will be lower than the design value after repeated cycles. The results of the fatigue tests showed that the energy dissipation system formed by the ceramic fiber friction blocks and the friction steel plates in the SCVF brace has a certain stability. The finite element simulation results are essentially consistent with the obtained test results, which is conducive to the use of finite element software for calculation and structural analysis in actual engineering design.

scholarly journals Experimental Study on Hysteretic Behavior of the Overlapped K-Joints with Concrete Filled in Chord

2019 ◽  
Vol 9 (7) ◽  
pp. 1456 ◽  
Author(s):  
Wenwei Yang ◽  
Ruhao Yan ◽  
Yaqi Suo ◽  
Guoqing Zhang ◽  
Bo Huang
Keyword(s):  
Plastic Deformation ◽  
Energy Dissipation ◽  
Cyclic Loading ◽  
Bearing Capacity ◽  
Failure Modes ◽  
The United States ◽  
Hysteretic Behavior ◽  
Tensile Failure ◽  
Element Analysis ◽  
Better Than

Due to the insufficient radial stiffness of the steel tube, the cracking of the weld and the plastic deformation of the string often occur under the cyclic loading of the hollow section pipe joint. In order to avoid such a failure, the overlapped K-joints were strengthened by pouring different concrete into the chords. Furthermore, to explore the detailed effect of filling different concrete in a chord on the hysteretic behavior of the overlapped K-joints, six full-scale specimens were fabricated by two forms, which included the circular chord and braces, the square chord and circular braces, and the low cyclic loading tests, which were carried out. The failure modes, hysteretic curves and skeleton curves of the joints were obtained, and the bearing capacity, ductility and energy dissipation of the joints were evaluated quantitatively. The results showed that plastic failure occurs on the surface of the chord of the joints without filling concrete, while the failure mode of the joints filled with concrete in the chords was the tensile failure of the chords at the weld of the brace toe, and the compressive braces had a certain buckling deformation; The strengthening measures of concrete filled with chord can effectively improve the mechanical properties of the K-joints, the delay of the plastic deformation of the chord, and improve the bearing capacity of the K-joints. Contrarily, the ductility coefficient and the energy dissipation ratio of K-joints decreased with the concrete filled in the chord. The hysteretic behavior of the K-joints with a circular chord and brace was slightly better than that of the K-joints with a square chord and circular brace, and the hysteretic behavior of the K-joints strengthened with fly ash concrete, which was better than that of the K-joints strengthened with ordinary concrete. The results of ANSYS (a large general finite element analysis software developed by ANSYS Company in the United States) analysis agreed well with the experimental results.

Experimental studies of a typical sprinkler piping system in hospitals

2016 ◽  
Vol 49 (1) ◽  
pp. 1-12
Author(s):  
Zhen-Yu Lin ◽  
Fan-Ru Lin ◽  
Juin-Fu Chai ◽  
Kuo-Chun Chang
Keyword(s):  
Failure Modes ◽  
Experimental Studies ◽  
Hysteresis Loops ◽  
Research Programme ◽  
Shaking Table ◽  
Piping System ◽  
Improvement Strategy ◽  
Flexible Pipes ◽  
Piping Systems ◽  
Cyclic Loading Tests

Based on the issue of life safety and immediate needs of emergency medical services provided by hospitals after strong earthquakes, this paper aims to introduce a research programme on assessment and improvement strategies for a typical configuration of sprinkler piping systems in hospitals. The study involved component tests and subsystem tests. Cyclic loading tests were conducted to investigate the inelastic behaviour of components including concrete anchorages, screwed fittings of small-bore pipes and couplings. Parts of a horizontal piping system of a seismic damaged sprinkler piping system were tested using shaking table tests. Furthermore, horizontal piping subsystems with seismic resistant devices such as braces, flexible pipes and couplings were also tested. The test results showed that the main cause of damage was the poor capacity of a screwed fitting of the small-bore tee branch. The optimum improvement strategy to achieve a higher nonstructural performance level for the horizontal piping subsystem is to strengthen the main pipe with braces and decrease moment demands on the tee branch by the use of flexible pipes. The hysteresis loops and failure modes of components were further discussed and will be used to conduct numerical analysis of sprinkler piping systems in future studies.

Comparing Hysteretic Behavior of Flexible Piers with Different Stirrup Ratio and Slenderness Ratio

2011 ◽  
Vol 261-263 ◽  
pp. 576-580
Author(s):  
Xiao Jing Yuan ◽  
Fan Liu
Keyword(s):  
Energy Dissipation ◽  
Bearing Capacity ◽  
Slenderness Ratio ◽  
Experimental Studies ◽  
Bridge Engineering ◽  
Hysteretic Behavior ◽  
Hysteresis Curve ◽  
Skeleton Curve ◽  
Displacement Ductility ◽  
Ductility Factor

Flexible piers have been widely used in bridge engineering due to its superior ductility. The stirrup ratio and slenderness ratio were deemed to have a most important impact on hysteretic behavior of them. Five flexible piers were made under static vertical loads and low cyclic horizontal reversed loads. The process of test was introduced and failure mechanism, hysteretic behavior, skeleton curve, ductility, energy dissipation capacity, and stiffness degeneration of flexible piers were analyzed. Experimental studies show that (1) Failure mode of specimen is bending failure and their ductility factor falls between 4.15 and 6.30; (2) displacement ductility factor improves with increasing of the stirrup ratio. Stirrup could greatly improve the capacity on ductility and energy dissipation, while it has little impact on the bearing capacity; (3) ultimate bearing capacity decline with the increase of slenderness ratio, however, when the slenderness ratio member is larger, the hysteresis curve is fuller and energy-dissipation is better.

Experimental Research on the Influence of the Pile Type and Stirrup on the Seismic Performance of PHC Piles

2012 ◽  
Vol 256-259 ◽  
pp. 2079-2084 ◽  
Author(s):  
Tie Cheng Wang ◽  
An Gao ◽  
Hai Long Zhao
Keyword(s):  
Energy Dissipation ◽  
Cyclic Loading ◽  
Seismic Performance ◽  
High Strength Concrete ◽  
High Strength ◽  
Loading Tests ◽  
Energy Dissipation Capacity ◽  
Pile Type ◽  
Cyclic Loading Tests ◽  
Reversed Cyclic

The influence of the pile type and the stirrup on the seismic performance was evaluated based on the results of reversed cyclic loading tests on the four prestressed high strength concrete (PHC) piles. It is indicated that the AB-type pile has the better seismic performance than the A-type pile from the results. The bearing capacity does not increase obviously with decreasing of the stirrup spacing and increasing of the stirrup diameter. The degradation of stiffness does not decrease significantly with decreasing of the stirrup spacing and increasing of the stirrup diameter. The energy dissipation capacity is improved with increasing of the stirrup diameter and decreasing of the stirrup spacing.

scholarly journals Experimental Studies on Seismic Performance of Precast Steel Reinforced Concrete Frame and Connections

2015 ◽  
pp. 349-357
Author(s):  
Xiang Hu ◽  
Weichen Xue ◽  
Yanbo Sun ◽  
Chenguang Li
Keyword(s):  
Reinforced Concrete ◽  
Energy Dissipation ◽  
Cyclic Loading ◽  
Seismic Performance ◽  
Experimental Studies ◽  
Frame Structures ◽  
Seismic Zone ◽  
Reversed Cyclic Loading ◽  
Steel Reinforced Concrete ◽  
Reversed Cyclic

A new type of precast steel reinforced concrete (PSRC) frame, which were composed of composite steel reinforced concrete (CSRC) beam, PSRC column and cast-in-situ (CIS) joint, were proposed in this paper. The assemble technique used in the ordinary steel structures were adopted in PSRC frames to improve the construction efficiency. The seismic performance of PSRC frame structures was investigated based on the test results of connections and frame. Firstly, full-scale internal connection specimens, including a CIS connection specimen RCJ-1 and a PSRC connection specimen PCJ-1, were tested under low reversed cyclic loading. Results revealed that both the specimens RCJ-1 and PCJ-1 exhibited similar performance in terms of loading capacity, stiffness degradation and energy dissipation. The ductility of specimen PCJ-1 was about 3.81, which was a little lower than the specimen RCJ-1. Then, a 1/3-scale PSRC frame structure specimen, namely PCF-1, was tested under low reversed cyclic loading. Results showed that the PSRC frame specimen PCF-1 was failed in mixed failure mechanism, which provide good energy dissipation capacity. The ductility coefficient of PCF-1 was about 3.45 indicating that the PCF-1 behaved in ductility manner. The results of this investigation could enrich the data available documenting the behavior of PSRC frame, and contribute to enlarge the application of PSRC frame structures in seismic zone.

scholarly journals Experimental Study on Energy Dissipation Performance and Failure Mode of Web-Connected Replaceable Energy Dissipation Link

2019 ◽  
Vol 9 (15) ◽  
pp. 3200 ◽  
Author(s):  
Zhanzhong Yin ◽  
Zhaosheng Huang ◽  
Hui Zhang ◽  
Dazhe Feng
Keyword(s):  
Finite Element ◽  
Energy Dissipation ◽  
Finite Element Simulation ◽  
Rotation Angle ◽  
Frame Structure ◽  
Seismic Events ◽  
Mechanical Behaviors ◽  
Braced Frame ◽  
Element Simulation ◽  
Section Size

In the current design method of the eccentrically braced frame structure, the energy dissipation link and the frame beam are both designed as a whole. It is difficult to accurately assess the degree of damage through this method, and it is also hard to repair or replace the energy dissipation link after strong seismic events. Meanwhile, the overall design approach will increase the project’s overall cost. In order to solve the above mentioned shortcomings, the energy dissipation link is designed as an independent component, which is separated from the frame beam. In this paper, the energy dissipation link is bolted to the web of the frame beam. Both finite element simulation and test study of eight groups of energy dissipation links have been completed to study their mechanical behaviors, and the energy dissipation links have been studied in the aspects of length, cross section, and stiffener spacing. The mechanical behaviors include the energy dissipation behavior, bearing capacity, stiffness, and plastic rotation angle. The results indicate clearly that the hysteretic loop of links in the test and finite element analysis is relatively full. By comparing the experimental and finite element simulation data, it can be found that the general shape and trend of hysteretic loop, skeleton curve, and stiffness degradation curve are basically the same. The experiment data explicitly shows that the energy dissipation link of web-connected displays good ductility and stable energy dissipation ability. In addition, the replaceable links possess good rotational capacity when the minimum rotation angle of each specimen in the test is 0.16 rad. The results of the experiment show that the energy dissipation capacity of the link is mainly related to the section size and the stiffening rib spacing of the link. The energy dissipation ability and deformation ability of the link is poorer as the section size becomes larger; meanwhile, these abilities are reduced with the decrease of the stiffening spacing. The experiment result shows that the damage and excessive inelastic deformations are concentrated in the link to avoid any issues for the rest of the surrounding elements, and the links can be easily and inexpensively replaced after strong seismic events. The results are thought provoking, as they provide a theoretical basis for the further study of the eccentrically braced frame structure with replaceable links of web-connected. In future work, the author aims to carry out his studies through optimized design methodology based on the yielding criterion.

scholarly journals Behavior of RC Eccentric Corner Beam-Column Joint under Cyclic Loading: An Experimental Work

2019 ◽  
Vol 5 (2) ◽  
pp. 295 ◽  
Author(s):  
Ali Basha ◽  
Sabry Fayed
Keyword(s):  
Energy Dissipation ◽  
Cyclic Loading ◽  
Experimental Work ◽  
Failure Modes ◽  
The Other ◽  
Experimental Result ◽  
Cyclic Loads ◽  
Shear Reinforcement ◽  
Column Joint ◽  
Fixed End

The present research investigates experimentally the behavior of the reinforced concrete BCJ joint under quasi-static cyclic loads for different mount of the shear reinforcement. The specimen consisted of two columns and two beams; one is a free end and the other is a fixed end. The shear reinforcement of the joint was 1Ø6 mm, 2Ø6 mm, and 3Ø6 mm. Three specimens were tested under quasi-static cyclic loading up to failure. The cracking loads, ultimate loads, deflection of the free end of the loaded beam, crack patterns and failure modes for BCJ were recorded and analyzed at each cycle. Also energy dissipation and stiffness degradation of all specimens were discussed. The experimental result indicates that the increase in the amount of the stirrups of the joint transmitted the main failure into the column far away from the joint. The increase in the amount of joint stirrups enhanced the joint capacity. The stirrups are most effective in is the middle third part of the BCJ than others two parts.

scholarly journals Study on an Innovative Flange Bolted-Welded Connection

2015 ◽  
Vol 9 (1) ◽  
pp. 870-875
Author(s):  
Yufeng Jiao ◽  
Guo Zhao
Keyword(s):  
Bearing Capacity ◽  
Failure Modes ◽  
Experimental Studies ◽  
High Strength ◽  
Bottom Flange ◽  
Load Bearing Capacity ◽  
Load Bearing ◽  
Hybrid Joint ◽  
Welded Connection ◽  
Cyclic Loading Tests

This paper proposes a new type of spliced joint, named flange bolted-welded hybrid joint, which is designed to splice I-shape beam to facilitate the construction of industrialized buildings. The flange, welded with the bottom beam flange as well as the web close to bottom flange, are jointed by high strength bolts. Stiffening plate is welded at top of the flange while downhand welding and high strength friction grip bolts are used for the top beam flange and the beam web, respectively. The connection reduces the construction period and costs. In this paper, monotonic and reversed cyclic loading tests were conducted on three full-scale specimens of this innovative joint to investigate its load-bearing capacity, energy-dissipating capacity and failure modes. The results indicate that the joint has high load-bearing capacity and great ductility. The failure mode is due to the slippage of flange bolts as well as the gap development between the two flange plates. The experimental studies enabled improvement of the design of the connection to be used in moment-resisting steel frame structures.

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