PROGRESSIVE COLLAPSE PERFORMANCE OF STEEL CONNECTION WITH EFFICIENT SEISMIC DESIGNS

International Research Journal of Engineering and Technology (IRJET) e-ISSN: 2395-0056
Volume: 10 Issue: 07 | Jul 2023 www.irjet.net p-ISSN: 2395-0072
© 2023, IRJET | Impact Factor value: 8.226 | ISO 9001:2008 Certified Journal | Page 56
PROGRESSIVE COLLAPSE PERFORMANCE OF STEEL CONNECTION WITH
EFFICIENT SEISMIC DESIGNS
SREEDEVI K1, ADILA ABDULLA KUNJU2
1Sreedevi K, Dept of civil Engineering, ICET Mulavoor, Kerala
2Adila Abdulla Kunju, Dept of civil Engineering, ICET Mulavoor, Kerala
---------------------------------------------------------------------***---------------------------------------------------------------------
Abstract - Corrugated plates are utilized in place of the flat
web of the beam at the region near to the column face, known
as the curved corrugated web RBS, in order to reduce the
beam's flexural strength and assure hinge formation in this
area. The corrugated web's application lowers the beam's
flange width-to-thickness ratio while boosting lateral and
torsional stability in the lowered section zone. To describe the
design process and determine the resistance to progressive
collapse, FEM is employed. Several models are built using the
provided details of the beam and column sections after the
numerical model's validation. Then, taking into account the
three possible depths for the corrugatedcells, thesemodelsare
examined under cyclic loading. Connections without RBS and
with RBS such as flange cut (FC-RBS), areusedforcomparison.
The findings demonstrate that the proposed connection
induces the formation of plastichinges inRBSzone, preventing
failure at the beam column junction. This recommended
connection performs better than the conventional FC-RBS
connection in terms of yield strength, rotation capacity,
ductility, and load bearing capacity.
Key Words: RBS connection, Corrugated web, Cyclic
loading, Seismic behavior
1. INTRODUCTION
Steel moment frame connections can be secured against
brittle failure by using Reduced Beam Section (RBS)
connections, which include weakening the beam near to the
column face. This technique makes sure that the beam has
less flexural strength in the RBS zone than in any other
adjacent regions, causing plastic hinges to develop here. By
preventing nonlinear behavior from spreading to the
connection, this aids in reducing brittle failure in this
location. Researchers have proposed a number of methods
for reducing the beam's moment capacity at the area where
the plastic hinge is gradually developed. The most common
RBS connection, referred known as ‘dog bone connection’,is
made by cutting off the beam's flange just beyond the
column face in order to ensure flexural yielding there. This
cut can be made using a straight cut, a tapered cut, or a
radius cut. Due to its enhanced seismic performance, the
Radius Cut RBS (RC-RBS) connection has been included to
the AISC 358-16.
When considerabledeformationoccurs,connections with
flange or web reduction may affect the mechanical
characteristics and produce structural displacement. In
particular, the web-reduction created a discontinuous force
transmission path, which subjected the beam web to an
additional concentrated force. Because ofthis, itisnecessary
to evaluate the load carrying capacity, deflection, and
cracking of beams with flange and web reductions, which
can be evaluated indirectly by their ability to sustain
progressive collapse.
Prior research concentrated mainly on how connections
performed with or without RBS. In this study, a new type of
RBS connection is created to allow for connections with
better ductility, load carrying capacity and energy
absorption. It has been feasible to compare the common
weld connections (W-RBS), traditional RBSconnections(FC-
RBS), and the new RBS connection (CW-RBS) using
numerical validation. The deformation, failure modes, load
carrying capacity, rotation capacity, moment capacity,
ductility, yield point, stress concentration, and strain
distribution are explained and analyzed in detail.
1.1 Corrugated Web RBS
It is possible to construct steel moment frames with more
acceptable seismic responses by using corrugated web RBS
connections, which have advantages over traditional RBS
connections. The corrugatedweb's geometryintheRBSzone
can also be changed in order to further enhance these
connections' seismic performance. In this study, a novel
corrugated web RBS connection, the curved cell web RBS
(CW-RBS) is presented. In the proposed connection, a full-
capacity rigid connection ismade by welding the beam using
Complete Joint Penetration (CJP) to the column's flange. In a
region close to the column, the beam's web is cut, and the
removed portion is replaced by a cell formed of two
corrugated plates. The cell is constructed using two curved
plates, known as the curved cell web RBS (CW-RBS)
connection. The paper goes into considerable detail in the
next part to describe both the design approach and the
suggested connection. The development of a finite element
model and its validation using the available empirical data
are then covered in the following parts. The model was
created for assessing the resistance to progressive collapse.
The examination of the beam's inelastic behavior in the RBS
zone and the energy dissipation capacity of the suggested
connection in comparison to conventional RBS is shown at
the end of the paper.

1.2 Review on Literature
Using radial cuts in the beam flange and circular aperture
in the beam web, Huiyun Qiao et al. (2020) [1] described a
new reduced beam section (RBS) connection that enables
more ductile connections.Ninedistinctspecimenswerebuilt
and evaluated in the investigation under a scenario of
removing the central column, without an RBS (RBS-0), with
flange reductions (RBS-1), and seven with web and flange
reductions (RBS-2). According to the findings, the RBS-0
specimen with brittle failure was ineffective at resisting
progressive collapse. While RBS-1 outperformed RBS-0 in
terms of ductility and resistance, it still needed to be
strengthened in order to withstand progressive collapse
after fracture. RBS-2 with web apertures created an arch
structure to release energy through ongoing deformations.
The diameter and the distance of the web opening, which
were associated with the emergence of archingandcatenary
action, were also two significant elements in RBS-2 that
affected its mechanical property.
2.MODELLING,ANALYSISANDPARAMETRICSTUDY
ON NOVEL CURVED CELL WEB REDUCED BEAM
SECTION
This chapter deals with the analysis andparametric studyon
novel curved cell web reduced beam section and finding the
optimum performance. Four models are created using
ANSYS as per the AISC provisions. The differentmodelsused
are CW-RBS 75x170x80mm, CW-RBS 50x130x80mm, CW-
RBS 75x130x80mm and CW-RBS 50x170x80mm. The
dimension details and material properties of the curved cell
web RBS are in Table 1 and 2 respectively.
Table -1: Dimension details
Section Dimension
Beam 200 × 100 × 5.5 × 8 mm
Column 250 × 250 × 9 × 14 mm
Table -2: Material properties
Fig -1: Geometric notations of CW-RBS
Fig -2: Geometric dimensions of RBS zone
Table -3: Limits for the geometric dimensions
Limits Max Min
0.5 bf ≤ a ≤ 0.75 bf 50mm 75mm
0.65db ≤ b ≤ 0.85db 130mm 170mm
0.1 bf ≤ c ≤ 0.25 bf 10mm 25mm
d = 0.4bf, 0.6bf ,0.8bf 40mm,60mm,80mm
CW-RBS is modelled in ANSYS with different specimen
dimensions like CW-RBS 75x170x80mm, CW-RBS
50x130x80mm, CW-RBS 75x130x80mm and CW-RBS
50x170x80mm. Modelling is done by using element type
SOLID186. CW-RBS is modelled using hexahedral which is a
20-noded mesh. Programme controlled coarse mesh is
adopted for meshing the column and beams. Load is applied
as displacement of 10mm according to displacement
convergence method.
Fig -3: Model of CWRBS
Analysis is carried out tostudytheperformanceofCW-RBS
with different dimensions. Nonlinear static structural
analysis is carried out in ANSYS. Load carrying capacity
and deformation is studied. The deformation diagramsare
shown in Fig 4 to 7.
Steel
Young’s modulus (E) =2 ×105 MPa
Poisson’s ratio (µ)= 0.3
Density (ρ) = 7850 kg/m3

Fig -4: Deformation of CW-RBS75x170x80
1.2 Results and discussion
The result obtained from the Nonlinear static structural
analysis of curved cell web RBS likeCW-RBS75x170x80mm,
CW-RBS 50x130x80mm, CW-RBS 75x130x80mm and CW-
RBS 50x170x80mm are compared with flange cut RBS.
Table -4: Comparison of results
Section
a
mm
b
mm
d
mm
Wmax
mm
Pmax
kN
%
RBS-FC - - - 246.06225.31 -
CW-RBS75X170X40 75 170 40 308.12329.17 46.10
CW-RBS75X170X60 75 170 60 341.05 426.6 89.34
CW-RBS75X170X80 75 170 80 401.05502.72123.12
CW-RBS50X130X80 50 130 80 437.35 523.2 132.21
CW RBS75X130X80 75 130 80 407.84522.79132.03
CW RBS50X170X80 50 170 80 405.67 493.4 118.99
Section
Θmax
=
Wmax/L
%
Mmax
=
Pmax
x L
Yield
Point
mm
%
Ductility
=
Wmax/
Yield
Point
RBS-FC 0.1871 - 296.28 60.07 - 4.10
CW-RBS
75 X170X40
0.2343 25.23432.86100.09 66.62 3.08
CW-RBS
75X170X60
0.2594 38.62560.98100.09 66.62 3.41
CW-RBS
75X170X80
0.3050 63.00661.08100.09 66.62 4.01
CW-RBS
50X130X80
0.3326 77.76688.01100.09 66.62 4.37
CW RBS
75X130X80
0.3101 65.76687.47100.09 66.62 4.07
CW RBS
50X170X80
0.3085 64.88648.82100.09 66.62 4.05

Table -5: Stress concentration and strain distribution in
beam and column
section
stress concentration in
beam (MPa)
strain distribution
in beam
RBS-FC 484.93 1.05
CW-RBS
75x170x40
485 1.846
CW-RBS
75x170x60
485 1.7747
CW-RBS
75x170x80
485 1.6503
CW-RBS
50x130x80
485 1.4062
CW RBS
75 x130x80
485 1.5619
CW RBS
50x170x80
485 1.677
section
stress concentration in
column (MPa)
strain distribution
in column
RBS-FC 93.81 0.00060
CW-RBS
75x170x40
119.6 0.00107
CW-RBS
75x170x60
123.97 0.00113
CW-RBS
75x170x80
129.47 0.00113
CW-RBS
50x130x80
137.96 0.00106
CW RBS
75 x130x80
128.02 0.00111
CW RBS
50x170x80
127.29 0.00108
Fig -8: Load deflection comparison
3. CONCLUSIONS
 Since the maximum load anddeflection wasobtainedfor
the specimen CW-RBS 75x170x80, the optimum value
for d is 80 mm and the maximum load carrying capacity
and rotation capacity is obtained for the specimen CW-
RBS 50x130x80.
 From the study of implementing novel curved
corrugated web reduced beam section when compared
with FC-RBS, it was found that,
o Load carrying capacity was increased by
132.21%
o Rotation capacity was increased by 77.76%
o Yield strength was increased by 66.62%
o Considerable increase in ductility is also
observed.
o Stress concentration in beam is 485 MPa andin
column is 137.96 MPa
o Strain distribution in beam is 1.4062 and in
column is 0.00106
 Since stress concentration in beam and strain
distribution in beam is more than column, the proposed
connections cause plastic hinges to emerge in the RBS
zone, thereby preventing failure at the beam column
junction.
 Beam column connection with RBS shows better
performance than beam columnconnectionwithoutRBS
because the load carrying and rotation capacity were
increased by 42.56% and 185.86% respectively.
 Delaying the rotation capacity and force capacity
increases the progressive collapse life of the connection.

REFERENCES
[1] Huiyun Qiao, Yu Chen (2020) Experimental study on
beam to column connection with RBS against progressive
collapse
[2] Ali Mansouri, Mohammad, Ehsan Fereshtehpour
(2021) Two novel corrugated web reduced beam section
connections for steel moment frames
[3] Mahmoud R. Maheria, Ashkan Torabib (2019)
Retrofitting external RC beam-column joints of an ordinary
MRF through plastic hinge relocation using FRP laminate
[4] Aboozar Saleh, Seyed Rasoul Mirghaderi, Seyed
Mehdi Zahrai (2016) Cyclic testing of tubular web RBS
connections in deep beams, School of Civil Engineering, The
University of Tehran
[5] Liangjie Q, Roberto T Leon, Mathew R Eatherton,
Jonathan L Paquette (2021) Parametric investigation on
the design of RBS moment connection with jumbo beams
and columns
[6] Seyed Rasoul Mirghaderi, ShahabeddinTorabian, Ali
Imanpour (2010) Seismic performance of the Accordion
Web RBS connection
[7] ThomasAlexanderHorton,ImanHajirasouliha, Buick
Davison, Zuhal Ozdemir (2021) More efficient design of
reduced beam sections (RBS) for maximum seismic
performance
[8] Ali Imanpoura, Shahabeddin Torabianb, Seyed
Rasoul Mirghaderic (2019) Seismic design of the double
cell accordion web reduced beam section

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