Behaviour of headed studs in composite beams: push-out tests

1988 ◽  
Vol 15 (2) ◽  
pp. 240-253 ◽  
Author(s):  
B. S. Jayas ◽  
M. U. Hosain

This paper briefly summarizes the results of tests conducted on 18 full-size push-out specimens and 4 pull-out specimens. The objective of the project was to study the behaviour of headed studs in composite beams with ribbed metal decks perpendicular and parallel to the steel beam. The longitudinal spacing of the headed studs and the rib geometry of the metal decks were the principal experimental parameters.Five of the push-out specimens had solid concrete slabs, in five specimens the ribbed metal deck was placed parallel to the steel beam, and in the remaining eight specimens the metal deck was perpendicular to the steel beam. In most cases 38 mm deck and 16 × 76 studs were used.Test results obtained by the authors appear to indicate that with some exceptions the current Canadian Standards Association and Load and Resistance Factor Design codes are able to predict stud strength correctly for specimens with solid slabs and with parallel ribbed slabs only when failure occurs owing to stud shearing, i.e., when the studs are spaced sufficiently apart. It is recommended that these codes include a provision to check the possibility of concrete-related failures when the longitudinal stud spacing approaches or falls below six times the stud diameter for solid and parallel ribbed slabs.Stud pull-out was the principal mode of failure in the specimens with perpendicular ribbed metal decks. An equation recently proposed by Hawkins and Mitchell appears to underestimate the capacity for specimens with 38 mm deck. For specimens with 76 mm deck, their equation overestimates the stud capacity. The authors have proposed two separate but similar empirical equations for specimens with 38 and 76 mm deck. Key words: composite beam, headed stud, stud shear capacity, stud pull-out failure, minimum stud spacing, perpendicular deck, parallel deck.

1989 ◽  
Vol 16 (5) ◽  
pp. 712-724 ◽  
Author(s):  
B. S. Jayas ◽  
M. U. Hosain

This paper summarizes the results of tests conducted on four full-size composite beams and two full-size push-off specimens which are companions of the first two beams. In these specimens, the ribbed metal deck was placed perpendicular to the beam span. Concrete pull-out was the principal mode of failure. The ultimate horizontal shear loads observed in the push-off specimens agreed reasonably well with those predicted using an empirical equation proposed by the authors. The predicted values of flexural capacity, calculated indirectly using the same equation, were in good agreement with those observed in the four beam specimens. Key words: composite beam, headed shear stud, stud shear capacity, stud pull-out failure, full-size tests, perpendicular ribbed metal deck.


2019 ◽  
Vol 2019 ◽  
pp. 1-16
Author(s):  
Shuangjie Zheng ◽  
Chen Zhao ◽  
Yangqing Liu

In steel and concrete composite structures, it is unfavourable to install many headed studs or perfobond ribs with narrow spacings at the joints. To solve this problem, a new type of a mixed shear connector was developed by combining a headed stud and perfobond rib at the same steel beam flange. In this paper, totally nine push-out tests were conducted. The main purpose was to compare the failure mode and the load-slip behavior of the headed stud, perfobond rib, and mixed shear connector. Furthermore, 19 nonlinear finite element simulations were performed. The effects of connector dimension and material properties on the structural behaviors of mixed shear connectors were studied. Based on the experimental and parametric study, an analytical equation was finally proposed to evaluate the shear capacity of perfobond rib with a headed stud mixed shear connector.


Author(s):  
Mohammed Abdulhussein Al-Shuwaili ◽  
Alessandro Palmeri ◽  
Maria Teresa Lombardo

Push-out tests (POTs) have been widely exploited as an alternative to the more expensive full-scale bending tests to characterize the behaviour of shear connections in steel-concrete composite beams. In these tests, two concrete slabs are typically attached to a steel section with the connectors under investigation, which are then subjected to direct shear. The results allow quantifying the relationship between applied load and displacements at the steel-concrete interface. Since this relationship is highly influenced by the boundary conditions of POT samples, different experimental setups have been used, where the slabs are either restricted or free to slide horizontally, as researchers have tried to reduce any discrepancy between POT and full-scale composite beam testing. Based on a critical review of various POT configurations presented in the dedicated literature, this paper presents an efficient one-sided POT (OSPOT) method. While OSPOT and POT specimens are similar, in the proposed OPSPOT setup only one of the two slabs is directly loaded in each test, and the slab is free to move vertically. Thus, two results can be obtained from one specimen, i.e. one from each slab. A series of POTs and OSPOTs have been conducted to investigate the behaviour and the shear resistance of headed stud connectors through the two methods of testing. The results of this study than were compared with those of different POTs setups conducted by other researchers. The new OSPOT results show in general an excellent agreement with the analytical predictions offered by both British and European standards, as well as the estimated shear resistance proposed other researchers in the literature. These findings suggest that the proposed one-sided setup could be used as an efficient and economical option for conducting the POT, as it has the potential not only to double the number of results, but also to simplify the fabrication of the samples, which is important in any large experimental campaign, and to allow testing with limited capacity of the actuator. 


2011 ◽  
Vol 8 (1) ◽  
pp. 29-34
Author(s):  
M. Youcef ◽  
M. Mimoune ◽  
F. Mimoune

This paper describes the reliability analysis of shear connection in composite beams with profiled steel sheeting. The profiled steel sheeting had transverse ribs perpendicular to the steel beam. The level of safety of shear connection, and failure modes were determinate. An extensive parametric study was conducted to study the effects on the safety and behaviour of shear connection by changing the profiled steel sheeting geometries, the diameter and height of headed stud, as well as the strength of concrete. We compared the level safety calculated using the American specification, British standard and European code for headed stud shear connectors in composite slabs with profiled steel sheeting perpendicular to the steel beam. It is found that the design overestimated the level safety of shear connection.


2018 ◽  
Vol 64 (2) ◽  
pp. 97-110
Author(s):  
V. Jayanthi ◽  
C. Umarani

AbstractShear connectors are designed in steel-concrete composite construction to transmit the longitudinal shear, to prevent separation of steel and concrete slabs, and also to increase the structural efficiency of the whole system. In this study, the performances of different types of shear connectors in steel-concrete composite specimens are evaluated by conducting push-out tests under monotonic loading conditions. An ISMB 200 @ 25.4 kg/m universal steel beam measuring 400 mm and a reinforced cement concrete slab measuring 300 mm with a breadth of 200 mm and a thickness of 200 mm reinforced with 8 mm diameter steel rods are used for the experimental study. The results reveal that the load-slip relationships for various types of shear connectors and failure mechanisms are obtained to identify those shear connectors which are more relevant to the steel - concrete composite members.


Author(s):  
Valentino Vigneri ◽  
Christoph Odenbreit ◽  
Matthias Braun

For composite beams using novel steel sheeting, the current Eurocode 4 rules sometimes overestimate the load bearing capacity of the shear connector. This is due to the larger rib heights and the smaller rib widths in comparison with the old studies, which have been carried out to calibrate the current design equations. The RFCS Project “DISCCO” investigated this phenomena and the working group under mandate M515, CEN/TC250/SC4/SC4.T3 is enhancing this equation and working on a proposal to be taken over in the new version of Eurocode 4.The proposed new equation covers the failure behaviour of the shear connection more in detail. The test results show, that the failure consists in a combined concrete cone and stud in bending. Due to the geometry of novel steel sheeting, the load bearing capacity of the headed stud shear connector is no more limited by its shear capacity, but by its bending capacity.A 3D non-linear finite element model is developed and validated through the support of the DISCCO push-out tests. A good agreement between numerical and experimental results in terms of force-slip behaviour is achieved. Special attention of this work lies on the numerical evaluation of the number of plastic hinges ny: a stress-based procedure is presented and the results are compared to the equations presented for new Eurocode 4.The numerical simulations show that the upper plastic hinge moves up as the slip increases due to the progressive crushing of the concrete in the rib. From the parametric study, it turns out that ny is linearly proportional to the embedment depth. Compared to pre-punched hole decking, through-deck welding specimen activates less plastic hinges in the studs because of the higher stiffness provided at the base of the stud.


1992 ◽  
Vol 19 (1) ◽  
pp. 1-10 ◽  
Author(s):  
M. R. Veldanda ◽  
M. U. Hosain

This paper summarizes the results of tests performed on 48 push-out specimens to investigate the feasibility of using perfobond rib type shear connectors in composite beams with ribbed metal decks placed parallel to the steel beams. The perfobond rib shear connector is a flat steel plate containing a number of holes. The results indicate that perfobond rib connectors can be effectively used in composite beams with ribbed metal decks placed parallel to the steel beams. An appreciable improvement in performance was observed in test specimens when additional reinforcing bars were passed through the perfobond rib holes. Shank shear was the principal mode of failure in specimens with headed studs. In specimens with perfobond rib, failure was triggered by the longitudinal splitting of the concrete slab, followed by the crushing of concrete in front of the perfobond rib. Key words: composite beam, shear connector, perfobond rib, headed stud, push-out test, metal deck.


2016 ◽  
Vol 2 (2) ◽  
pp. 52-62 ◽  
Author(s):  
Hamid Eskandari ◽  
Tahereh Korouzhdeh

This study presents exact solution analysis for the cost optimization of Composite Beams (CB) based on the Load and Resistance Factor Design (LRFD) specifications. Matlab code formulation is applied to analysis of sensitivity for various parameters such as cost of concrete, steel beam, span length, concrete slab thickness, compressive strength of concrete, steel beams space and shear connectors on CB. Almost 20 thousands design were analysed to obtain various contour which be found that it is feasible, efficient and effective and capable in optimization of composite beam designs.The obtained results represent that many of the contour are capable by achieving substantial cost savings for composite materials. Therefore, the analysis can be developed for practical designs to structural designers. A parametric study was also conducted to investigate the effects of IPE, IPB, INP profiles, UNP size and thickness of slabs and beam length on the cost optimization of CB.


Author(s):  
Ana Maria Pascual ◽  
Ulrike Kuhlmann ◽  
Jakob Ruopp ◽  
L. Stempniewski

The capacity of the headed studs when they are close to the edge may be limited by the splitting forces in the concrete. In the Eurocode 4 Part 2 Annex C the shear capacity under this particular arrangement of the studs, which is directly dependent on the distance to the edge, is formulated. In addition, the geometrical restrictions to prevent the failure by pull-out of the studs are also given in clause C1 (2). These rules are based on push-out tests for the edge position where tension forces in the lying studs spread over the width of the specimen in this unfavorable way. Nonetheless, the current limits lead to extremely long studs and represent a severe restriction, and on the other hand, it is still an open question whether in real buildings or bridge girders the tension stresses that produce the pull-out appears in the same way as in the push out tests. In this paper the revision of these restrictions is presented together with a research for the alternative use of EN 1992-4 plus RFCS Project INFASO for the verification of the tension loads on the studs. 


1994 ◽  
Vol 21 (4) ◽  
pp. 614-625 ◽  
Author(s):  
E. C. Oguejiofor ◽  
M. U. Hosain

This paper summarizes the results of 40 push-out test specimens with a new type of shear connector called perfobond rib. This connector is a flat steel plate with a number of holes punched through. The test specimens were designed to study the effect of a number of parameters on the shear capacity of the connection. These were the number and spacing of rib holes, transverse reinforcement, and compressive strength of concrete. The main objective of this study was to derive an expression for predicting the capacity of perfobond rib connector based on the results of the parametric study.The test results indicate that the shear capacity of the perfobond rib connector increases with the number of rib holes as long as the hole spacing is at least 2.25 times the diameter of the holes. The effect of increasing the transverse reinforcement ratio from 0.27% to 0.36% was an increase of approximately 16% in the shear capacity of the connection. Similarly, an increase of 36% in the shear connection capacity was achieved due to a 63% increase in concrete strength.An expression for computing the shear capacity of perfobond rib connectors is proposed. A regression analysis, which is based on a model that takes into account the contributions of concrete dowels formed by the rib holes, the transverse reinforcement, and the strength of concrete, was used in the derivation. Key words: composite beam, perfobond rib connector, headed stud, push-out test, compressive strength of concrete, transverse reinforcement.


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