Behaviour of bolted link-column joints in eccentrically braced frames

1995 ◽  
Vol 22 (4) ◽  
pp. 745-754 ◽  
Author(s):  
T. Ramadan ◽  
A. Ghobarah

Current seismic provisions require that shear links in eccentrically braced frames be fully welded to the column flanges at the link-column joint. Since field welding may have its disadvantages, the use of bolted extended end-plate connection is examined. An experimental program is conducted to assess the response of extended end-plate connections of link-column joints in eccentrically braced frames. Six link-column joint specimens are tested using a cyclic load that represents the severe load reversals that the frame may be subjected to during strong earthquakes. The specimens are selected on the basis of different connection designs. Measurements of forces, strains, and displacements are made. Interaction curves relating the shear force and moment acting on links with semirigid connections are developed. The slip tendency and energy dissipation capacity of the different specimens are compared. On the basis of the test results, a design procedure is developed for the bolted extended end-plate link-column connection. It is concluded that bolted extended end-plate connections can be used for link-column joints of eccentrically braced frames. In properly designed connections bolt slippage was not measured even at high shear forces that are characteristic of link-column joint. Existing guidelines for the design of extended end-plate link-column joints are modified to account for the variable shear force and moment associated with links of different lengths. Key words: steel, frame, eccentric, braced, bolted, end plate, link, connection.

1996 ◽  
Vol 23 (1) ◽  
pp. 277-286 ◽  
Author(s):  
S. Mourad ◽  
R. M. Korol ◽  
A. Ghobarah

Extended end-plate connections have been widely used in moment-resisting steel frames with W-shape columns, due to their sufficient stiffness and moment capacity. In addition, such connections are easy to install and permit good quality control. Extended end-plate connections can also be employed in moment-resisting frames with hollow structural section columns by using high strength blind bolts. These bolts have been developed for installation from one side only where the rear side of the connection is inaccessible. In this study, a quantitative procedure for detailing and designing beam extended end-plate connections for rectangular hollow structural section columns using high strength blind bolts is proposed. The design procedure is consistent with the design philosophy given in limit-state codes. The proposed design is based on the results obtained from an experimental program and an analytical study. Key words: design, end plate, connection, hollow section, blind bolts, steel, frame.


2014 ◽  
Vol 1025-1026 ◽  
pp. 878-884
Author(s):  
Jong Wan Hu ◽  
Jun Hyuk Ahn

This paper is principally performed to survey end-plate connection are described in the next part based on ideal limit states. The determination of end-plate based on the full plastic strength of the steel beam in accordance with 2001 AISC-LRFD manual and AISC/ANSI 358-05 Specifications. The bolted connections considered herein were performed to include the end-plate component of moment connections. This study is intended to investigate economic design for end-plate connections. In addition, the proposed end-plate model is evaluated by comparing the required factored bolt strength. The end-plates using 8 high strength bolts with wider gages demonstrated this design. The equations belonging to the step-by-step design procedure are described based on complete proving of design. Finally, new design methodology is applied to end-plate connections suggested in this study.


2013 ◽  
Vol 284-287 ◽  
pp. 1330-1333
Author(s):  
Poi Ngian Shek ◽  
M.Md. Tahir ◽  
Cher Siang Tan ◽  
Arizu Sulaiman

A series of retrofitted extended end-plate connections have been tested experimentally and evaluated using the component method specified in Eurocode 3. The component method decomposed the end-plate connection into several components, including the tension zone, compression zone, vertical and horizontal shear zone that occurred at the bolt, end-plate, beam and column. Based on the theoretical model, the moment resistance and the initial stiffness of a connection can be predicted. Four experimental tests on the retrofitted extended end-plate connections have been conducted to verify the proposed design method. From the experiment tests, all moment resistance of the connections showed good agreement with theoretical predictions, which establish a reliable foundation to predict the moment resistance of the retrofitted end-plate connection. All initial stiffnesses calculated from theoretical predictions do not represent the actual behaviour of tested connection. All tested connections can be classified as partial strength based on EC 3: Part 1.8, in condition the welding capacity is at least 50% higher than the capacity calculated from the component method.


2015 ◽  
Vol 9 (1) ◽  
pp. 653-665
Author(s):  
Shizhe Chen ◽  
Chao Zhou ◽  
Zhan Wang

To investigate the influence of end-plate stiffeners on the initial rotational stiffness of extended end-plate internal joints, an experimental program was carried out to investigate the rotational behavior of the joints. Two finite element methods (FEMs) were proposed using ABAQUS software. The stress distribution, plastic development, and deformation characteristics of extended end-plate joints were determined from a comparison of the results of experiments and numerical analyses, and a calculation method for the initial tensile stiffness of the end-plate stiffener was proposed. This investigation presented herein demonstrates that (1) the angle and thickness of the stiffener strongly influence the initial tensile stiffness of the joint; and (2) component-based FEMs can accurately reflect the entire loading process of joints in a simple and efficient manner.


2019 ◽  
Vol 29 ◽  
pp. 02008
Author(s):  
Dominiq Jakab ◽  
Aurel Stratan ◽  
Dan Dubina

During the European research project entitled EQUALJOINTS (European pre-Qualified steel JOINTS) [1], which recently concluded, the matter of providing a set of pre-qualification procedures for moment resisting beam-to-column connections which are currently used in Europe has been addressed. During the experimental campaign 24 specimens with bolted extended end-plate connections with haunches were tested. The current paper presents the numerical model which has been developed such that numerical testing may be performed to further investigate specific details. In what concerns the material, an isotropic material model has been calibrated and used based on tensile tests of coupons extracted from the specimens to model the actual plastic behaviour. Moreover, the imperfections of the beam have been taken into account using a bucking analysis to model as accurate as possible the specimens tested. The interaction between parts has been modelled using contacts with different interaction laws. The model used for the bolt has been calibrated such that the preloading and failure replicate the behaviour of the actual bolts used in the experiments.


2013 ◽  
Vol 680 ◽  
pp. 205-210
Author(s):  
Ikhlas S. Sheet ◽  
Umarani Gunasekaran

An experimental program under cyclic load is performed on two half-scale interior moment end-plate connections to concrete filled tubular (CFT) columns. Flat and curved stiffened extended end-plates were welded to the steel beams in the shop, and bolted on the site to the square and circular CFT column tubes respectively, using steel rods passing through the column. The experimental results demonstrated that both circular and rectangular end-plate connections showed similar performance in a ductile manner and the stiffener elements were effective to form the plastic hinges away from the welding zone, also the proposed curved end-plate connection with rods passing through the column in “X” shape was effective. The test specimens showed a plastic rotations capacity of 0.054 radian.


2019 ◽  
Vol 2019 ◽  
pp. 1-11 ◽  
Author(s):  
Rongqian Yang ◽  
Xuejun Zhou

In order to study the mechanical behavior of bolted beam-column connections, the accuracy and applicability of the finite element model were firstly validated according to the published experiments on end-plate connections using ABAQUS. Then, in order to discuss the mechanical behavior of connections, three semirigid connections which are convenient for prefabricated construction, including top-and-seat angle connections with web and ear plate, extended end-plate connection, and T-stub connection, were examined using numerical simulation analysis to study and compare their capacity, hysteretic behavior, ductility, and degradation characteristics in detail. The results showed that the finite element models that were built could effectively simulate the load bearing behavior of bolted connections under both single-direction loading and cyclic loading. The three connections showed good load bearing capacity. The connectors significantly affected the energy dissipation capacity under load. The extended end-plate connection demonstrated the best performance in both mechanical behavior and manufacture and installation, so it would therefore be the preferred option.


2013 ◽  
Vol 321-324 ◽  
pp. 1766-1769
Author(s):  
Jian Li Zhao

Extend end-plat bolted connections are widely used in steel frames. The rotational stiffness has great influence on steel frame stiffness and deformation. The decrease of the frame lateral stiffness, due to connection rotational deformability, leads to the increase of the period of vibration and the frame sensitivity to second-order effects. This thesis divides the end plate into several parts equivalent to different Timoshenkos beams to determine their contribution to rotational stiffness of the connection. Then stiffness of all parts and bolts is given, and then the component method is used to calculate rotational initial stiffness of extended end-plate connections. Comparisons with results of ANSYS and related tests show that the proposed equations have excellent precision. And the calculating process is simple and easily applicable in practice.


Vestnik MGSU ◽  
2019 ◽  
pp. 179-187
Author(s):  
Ruslan I. Bagautdinov ◽  
Zaur S. Daurov ◽  
Yuriy P. Komarov ◽  
Nikolaiy N. Mostovskiy

Introduction. One of the greatest accents in the steel structures researches is the optimization of the design model. It is possible to reduce the cost of steel structures, optimize moment distribution and dynamic characteristics of the frame using the finite secant stiffness, which can be obtained by the described in the paper numerical modeling method. There are a lot of perspectives for the engineer in the field of numerical modeling. Most of them are possible to implement in the design procedure nowadays, but it is important to develop methods and standards for numerical modeling, in order to obtain convenient tools and reliable results. In order to study this issue in more depth, the “moment - turn” curve was studied, maximum stress values were determined, and rigidity and strength characteristics were prepared for each type of joint for structural analysis. Materials and methods. In the program Ansys was modelling three types of steel joints: end-plate connections, double web-angle connections and top and seat angle connections. Results. For three types of joints was obtained ultimate moment, location of destruction and moment-rotation curve. For extended end-plate connections was comparison of the obtained curve with experimental data. Conclusions. Three types of steel joints were modeled in the paper. The numerical modeling results show good correlation with the experimental ones. The data about the behavior of the joints were extracted and analyzed. As result, “moment-angle of rotation” curves were obtained. Finite secant stiffness of the joints for considering steel structures was obtained in the analysis. The resulting finite secant stiffness can be used in the steel frames design procedure.


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