2020 SCIENCELINE  
Journal of Civil Engineering and Urbanism  
Volume 10, Issue 2: 13-20; March 25, 2020  
ISSN-2252-0430  
DOI: https://dx.doi.org/10.29252/scil.2020.jceu2  
Comprehensive Performance Evaluation of the Composite  
Connection of Steel Joist Embedded in Concrete Girder  
Behnam Abbasalizade1 and Mahdi Chavoshi2  
1Postgraduate Student, Faculty of Engineering, University of Tabriz, Tabriz, Iran  
2Postgraduate Student, Faculty of Engineering, University of Bonab, Bonab, Iran  
Corresponding author’s Email: behnamcivil1369@gmail.com  
ABSTRACT  
Great deal of studies has been, so far, conducted on the performance of Composite Reinforced Concrete-Steel  
(RCS) beam-to-column connections. This paper deals with performance of composite connection of embedded steel  
joist in concrete girder with appropriate numerical analysis. The proposed model is validated by experimental data  
presented in reference studies. performance of connection of steel beam to concrete girder are, however, assessed  
through different approaches including influences of embedment ratio, double web angle, size of web angle, tie  
distances, studs, steel beam with flanges cut in connection zone and plates in web of steel beam. As a result, an  
appropriate embedment ratio is offered to achieve maximum bending capacity of the connection. Using double web  
angles at the embedment region, however, reduce the ratio. Damage analyses show that bending capacity of the  
concrete girder slightly reduces in the connection zone. Better performance of steel plate installed in web at  
connection zone is also observed among composite connection approaches. Using low tie distances at connection  
zone increases capacity by 10%. Performance of double web angle is, further, compared under hysteretic and  
monotonic loadings. The ratio of L/h in hysteretic behavior of connection was 20% higher than that of monotonic  
loading.  
Key words: Composite Beam-To-Column Connection, Embedment Length, Bending Capacity, Steel Joist-Concrete  
Girder Connection  
INTRODUCTION  
(Salvatore et al., 2005). Some researches were done on the  
behaviour of confined concrete using Drucker-Pruger type  
plasticity model in ABAQUS (Yu et al., 2010). A finite  
element model of composite frames was developed using  
shell elements (Bursi et al., 2005). An experimental model  
was used to evaluate the strength deterioration and damage  
propagation of RCS connections (Chou and Chen, 2010).  
Sustained damages to RCS connection in high seismic risk  
zones were investigated (Parra-Montesinos et al., 2003).  
The seismic behaviour of the steel beam-to-reinforced  
concrete column connection with and without floor slab  
was studied (Cheng and Chen, 2004). Composite frame  
structures having high-strength concrete columns confined  
by continuous compound spiral ties and steel beams were  
studied (Li et al., 2012). Seismic behaviour of RCS frames  
based on FEMA-356 and allowable rotation criterion were  
assessed (Farahmand Azar et al., 2013). It is desirable to  
design the coupling beams as shear-yielding members  
since a shear-critical coupling beam exhibits a better  
energy dissipation mode than a flexure-critical coupling  
beam (Park and Yun, 2005). Some researchers have been  
carried out on the interaction of shear force-bending  
In recent years, composite connections have gained  
popularity among researchers due to the optimal usage of  
concrete and steel in resisting the applied forces to the  
structures. Few specific guidelines are available for the  
connection of steel secondary beams embedded in  
reinforced concrete girder. For this reason, investigating  
the behaviour of composite connections is of paramount  
importance. Their applications include column base  
connections in steel structures, embedded steel coupling  
beams in RC shear walls and RCS frames. Furthermore,  
roof systems having steel joists incorporated in concrete  
frames reduce the overall weight of the structure, and  
therefore the seismic loads applied to it. Ease of  
concreting, elimination of framework, capability to cover  
long spans in powerhouses (attributed to the high moment  
of inertia of steel profiles) and reduction in cost and  
construction time are some advantages of these roof  
systems. Currently few guidelines are available for steel  
joists embedded in concrete girder. Moment-resisting  
frame structures of high ductility class were studied  
To cite this paper: Abbasalizade B and Chavoshi M (2020). Comprehensive Performance Evaluation of the Composite Connection of Steel Joist Embedded in Concrete Girder. J.  
Civil Eng. Urban., 10 (2): 13-20. DOI: https://dx.doi.org/10.29252/scil.2020.jceu2  
13  
Abbasalizade and Chavoshi, 2020  
moment in steel joist-concrete girder connections and  
between steel joist and concrete slab, “tie” option is used  
in ABAQUS to simulate the behaviour. Loading and  
boundary conditions of the verified model are shown in  
figure 2 in which two ends of the concrete girder are  
completely fixed and the load is transmitted to the  
concrete slab via four plates.  
proposed some equations (Yu et al., 2011). In this study, a  
specific length of steel joist was embedded in concrete  
with an angle shear connector. Hence, embedment length  
and its calculation are crucial.  
MATERIAL AND METHODS  
Validation of finite element model  
Finite element model  
In order to corroborate the proposed finite element  
model, load-displacement diagram of the simulated model  
was compared with the experimental model in figure 3.  
Also, Crack pattern of the aforementioned models is  
shown in figure 4. 12354 8-node linear brick, reduced  
integration (C3DR8) solid elements plus 397 2-node linear  
3-D (T3D2) truss elements were employed to the model.  
Details of reinforcements and their properties are shown in  
Tables 1 and 2. Mid-span force-displacement relationship  
of the steel joist is shown in figure 5. As it can be seen  
model behaves linearly till the 25mm deflection  
(corresponding force, 390kN). Afterwards, when the load  
reaches 550kN, steel joist slips inside the concrete girder  
causes failure and damage.  
A. General descriptions  
In order to simulate the real behaviour of the  
connection, four components need to be modelled:  
1) Contact between steel joist and concrete girder in  
the embedded region.  
2) Contact between steel joist and concrete slab.  
3) Interaction between reinforcing bars and  
concrete.  
4) Contact between anchor bars and concrete girder.  
B. Material model  
The mechanical behaviour of concrete was simulated  
using a Concrete Damaged Plasticity (CDP) model for  
which the pertinent parameters were estimated by uniaxial  
stress. Stress- strain relationship is shown in figure 1.  
C. Material Modelling Of Reinforcing Bars  
Regardless of the reinforcement service stage and  
Bauschinger effect in their stress strain relationships, ties  
and longitudinal reinforcements are assumed ideally  
elasto-plastic for simplification (Li et al., 2012).  
Figure 2. Loaded and meshed model  
Figure 1. Stress–strain relationship of reinforcement (Li et  
al., 2012)  
D. Contact model between concrete-reinforcing  
bars, concrete and steel  
Interaction model between concrete and bars is of  
embedded type and frictional behaviour has been adopted  
for the contact between steel joist and concrete girder with  
friction coefficient of 0.7. Moreover, assuming no slip  
Figure 3. Specimen model (Yu et al., 2011)  
14  
J. Civil Eng. Urban., 10 (2): 13-20, 2020  
RESULTS AND DISCUSSION  
Table 1. Details and size of specimen  
Detailed parameters of the specimen  
Finite element investigation of steel joist concrete  
girder connection  
Longitudinal  
reinforcement  
Length  
(mm)  
Section (mm2)  
Tie  
Member  
A. Overview  
D12  
@200  
Girder  
Slab  
320*900  
12-D20&8-D20  
2000  
-
As mentioned in previous sections, ABAQUS  
software was used for evaluating the performance of  
composite connection of steel joist embedded in concrete  
girder. The new finite element method was employed to  
investigate the influence of embedment length of steel  
joist in concrete girder on the bending capacity of the  
connection as well as the performance of double web  
angle shear connectors embedded in concrete based on the  
specifications outlined in Table 3. L/h is the embedment  
ratio where L is the embedment length and h is the height  
if the steel joist. Besides, angle shear connectors of  
(a×a×b) are of leg length, a, and thickness of, b.  
-
23-D8  
-
-
-
Steel  
Beam  
HN400×220×10×12  
5000  
Table 2. Properties of Materials  
Compression  
strength (N/mm2)  
Tensile strength  
(N/mm2)  
Specimen  
Concrete girder & slab  
Steel reinforcement  
Steel beam  
20.1  
1.84  
2.05  
2.05  
369.7  
360.8  
B. Influence of embedment ratio (L/h) on the  
bending capacity of connection  
Table 3. Details and size of cantilever model  
In order to investigate the so-called parameters, steel  
joist was modelled like a cantilever IPE240 beam as  
shown in figure 6. A 200mm displacement was applied to  
the free end of the cantilever and the load vs. displacement  
diagram which is indicative of the bending capacity of the  
capacity was drawn. Furthermore, steel joist was analysed  
under several embedment ratios (Figure 7) in concrete  
girder and a comparison was made with the fixed type  
(load vs. displacement) for each ratio. Based on the  
results, it is seen that L/h=1.78 provides the maximum  
bending capacity and acts like a rigid connection. Table 4  
lists the increase in stiffness in relation to the given  
embedment ratios. Figure 8 also shows validity of the ratio  
with IPE270.  
Detailed parameters of the specimen  
Longitudinal  
reinforcement  
Length  
(mm)  
Member  
Section (mm2)  
Tie  
D10  
@200  
Girder  
Slab  
300*400  
-
7-D20  
5000  
-
23-D8  
-
-
Steel  
Beam  
IPE150  
-
1500  
600  
500  
400  
300  
200  
100  
0
Experimental  
Numerical  
0
20  
40  
60  
80  
Steel beam midspan deflection (mm)  
Figure 5. Comparison of load-displacement diagram  
obtained from numerical and experimental analyses  
Figure 4.  
experimental models (Yu et al., 2011)  
Crack pattern of the numerical and  
Figure 6. Embedded steel beam in concrete girder  
15  
Abbasalizade and Chavoshi, 2020  
Table 4. Increase of bending capacity and failure force in  
relation to (L/h)  
on capacity of connection. As can be seen, thickness of  
angle has negligible effect on rigidity of connection while  
high efficiency of angle height is apparent.  
L/h  
Capacity increasing (%)  
Failure force  
0.57  
1
1.78  
-
31  
24  
7.64  
13.24  
16.95  
Figure 9. Connection detail of double web angle  
(40×40×4) in embedded region  
Figure 7. Influence of embedment ratio on the bending  
capacity of the connection  
25  
20  
15  
10  
rigid connection  
Connection With angle40x40x4(L/h=1)  
connection without angle(L/h=1)  
5
0
0
50  
100  
150  
200  
250  
Canteliver beam deflection (mm)  
Figure 10. Bending capacity of the embedded connection  
with web shear connector  
Figure 8. Load-deflection of IPE270  
Table 5. Effect of angle size on bending capacity  
increasing  
C. Investigation of the double web angle  
connection in the embedment region  
Size  
Capacity increasing (%)  
Angle 30×30×3  
Angle 30×30×4  
Angle 30×30×5  
Angle 40×40×4  
-
3
2
In order to investigate the influence of web shear  
connector in the bending capacity of the connection,  
double web angle shear connectors were employed in the  
embedment region (L/h=1). As shown in figure 9, a  
nonlinear static analysis was carried out with the same  
boundary conditions as before. Moreover, a comparison  
was made between the load-displacement curves of the  
analysis with that of the cantilever beam (Figure 10).  
Results indicate that the connection with L/h=1 and double  
web angle connections (L 40×40×4) yields the maximum  
bending capacity. Therefore it is deduced that this  
connection provides economical detailing with a decrease  
of 40% in embedment length when compared to the  
L/h=1.78 case. In addition according to figure 10, for a  
given L/h ratio, shear connector increases the bending  
capacity by 20%. Table 5, reports effect of size of angles  
11  
Influence of ties distances in connection on the  
bending capacity of the connection  
Sensitivity of connection capacity to ties distances is  
assessed considering distances equal to 25, 50 and  
100mm. Figure 11 demonstrates that as ties distances  
decrease, capacity of connection increases.  
Influence of studs in connection on the bending  
capacity of the embedment region  
Another detail of connection is evaluated based on  
using studs in steel beams web. Studs with 25mm diameter  
and length of 250mm are modeled in both sides of steel  
16  
J. Civil Eng. Urban., 10 (2): 13-20, 2020  
beam as shown in figure 12. Rigidity of connection  
increases in this detail as seen in figure 13. Further  
modelling is carried out with one stud in both sides of steel  
web which is shown in figure 14. Figure 15 shows  
sensitivity of this connection to diameter of stud. It is seen  
that effectiveness of diameter of stud on rigidity of  
connection is insignificant.  
Figure 14. Detail of one stud in embedded region  
(a)  
Figure 11. Effect of ties distances on connection capacity  
(b)  
Figure 15. Effectiveness of diameter of stud on rigidity of  
connection; (a) 25mm; (b) 30mm  
Figure 12. Detail of studs in embedded region  
Influence of steel without flanges on the bending  
capacity of the embedment region  
I-shape steel beams transmit bending moments  
through flanges while angles and stiffeners are used to  
make rigidity of this detail of connection. It is noted that  
holes made in web of beam are considered to bars of  
concrete beam in practical operations. Details are shown in  
figure 16. This kind of connection gives more damages to  
concrete girder in embedded region due to lack of flanges  
as seen in figure 17. Figure 18 shows that rigidity of this  
connection decreases by 17% respect to presence of  
concrete girder only.  
Figure 13. Effect of studs on rigidity of connection at  
embedded region  
17  
Abbasalizade and Chavoshi, 2020  
Figure 19. Modelling of connection with steel plate in  
embedded region  
Figure 16. Detail of steel without flanges at embedded  
region  
Figure 20. Effectiveness of steel plate on capacity of  
connection  
Figure 17. Tensile damages of connection at embedded  
region  
Figure 21. Comparison of semi rigid connections  
Hysteretic behaviour of the double web angle  
connection in the embedment region  
Figure 18. Reduction of connection rigidity in case of  
steel without flanges in embedded region  
A cantilever beam with length of 1.5m using double  
web angles (L 40×40×4) and L/h=1 connected to a 30 by 40  
cm concrete girder with 2m length is subjected to hysteretic  
loading. Loading protocol is shown in figure 22.  
Connection capacity subjected to both monotonic and  
hysteretic loadings at L/h=1 is compared in figure 23.  
Latter shows lower capacity respect to former. The capacity  
of connection increases as embedment length increases and  
reaches as high as monotonic loading capacity with L/h=1.  
Figure 24 shows that the hysteretic loading capacity of  
connection with L/h=1.2 is as high as monotonic loading  
capacity with L/h=1.  
Influence of steel plate on the bending capacity of  
the embedment region  
Steel plates are used to analyze capacity of connection  
rigidity as modeled in figure 19. Figure 20 shows that this  
detail reduces rigidity of connection up to 8%. Taking into  
account all kinds of abovementioned connections, it is  
concluded that semi rigid (or hinged) connection is  
approached with L/h=1 and using steel plate in web of  
steel joist. Capacity of both details is observed in figure  
21. Concrete damage in embedded area is reduced using  
steel plate. Higher capacity of this detail is apparent.  
18  
J. Civil Eng. Urban., 10 (2): 13-20, 2020  
double web angle shear connectors reduces this ratio to  
L/h=1. In other words, the interaction between the double  
web angles and concrete prevents the slipping of the steel  
joist inside the concrete girder. Using shear connectors and  
studs at connection zone can decrease length of  
embedment and help connection be more practical.  
Bending capacity of the concrete girder was also reduced  
by 10% in presence of steel joist under analysis of  
concrete damage plasticity. Further conclusions can be  
drawn as below:  
1. Using low tie distances at connection zone  
increases capacity by 10%.  
Figure 22. Hysteretic loading protocol  
2. The more studs at connection area, the more  
rigidity of connection  
3. The ratio of L/h in hysteretic behavior of  
connection was 20% higher than that of monotonic  
loading.  
4. In couple steel beam embedded in concrete shear  
wall, presence of shear connector can be ignored by  
embedding length of beam as much as twice of steel beam  
height.  
5. Using plates installed in steel beam web at  
connection zone shows better capacity than that of steel  
beam with flanges cut at connection area.  
Figure 23. Comparison of connection capacity under  
hysteretic and monotonic loadings (L/h=1)  
DECLARATIONS  
Authors’ contributions  
Authors of this research paper have directly  
participated in the planning, execution, or analysis of this  
study and have read and approved the final version  
submitted.  
Conflict of interest  
We hereby state that, there is no conflict of interest  
whatsoever with any third party.  
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In this paper, a numerical analysis through ABAQUS  
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