The document discusses the research work done in three stages (RPS) to analyze stress concentration factors (SCF) in steel connections under cyclic loading. In RPS 1, literature on steel connections was reviewed and ABAQUS was used to model and validate the behavior of a welded moment connection. RPS 2 identified stress concentration problems and modeled prequalified connections in ABAQUS to analyze load-displacement behavior and SCF. RPS 3 conducted parametric studies to analyze SCF and cyclic behavior of a type 1 connection using ABAQUS. The research concluded that reinforcements like stiffeners can reduce SCF, and haunched connections have the lowest SCF and highest stiffness.

1. Points Discussed in RPS 1
 Literature Survey
Connections shortlisted for study
Cyclic loading protocols and its details
Intro to ABAQUS
Finite element mesh sensitivity analysis and optimization for
connection geometry
Software verification is done by comparing standard moment
connection cyclic loading data with abacus data
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2. Conclusive points of RPS 1
 Pre Qualified welded connections can be used for further study
Sufficient research literature is available
Mesh sensitivity analysis shows that 20mm element size is sufficient
SAC protocol loading can be used to study the cyclic behavior of steel
connections
Nonlinear hysteretic behavior of steel connection achieved in
ABAQUS is well matched with tested data of the connection.
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3. Points Discussed in RPS 2
 Stress concentration problem identified in steel connections and
literature reviewed
Pre-qualified connections designed as per AISC and IS code guidelines
FEM modeling done in ABAQUS
Load vs Displacement behavior
Maximum von mises stress vs load behavior
Stress concentration factor vs load behavior
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4. Conclusive points of RPS 2
 Parallel sections can satisfy all the design requirement
SCF factor in haunch connection is lowest
Stiffness of haunch connection is highest
High plastic strain in web region of column so diagonal stiffener of
doubler plate is required
SCF factor stay linear in elastic stage and decreases as in the plastic
stage
Reinforcements in connections like column web stiffener plats and
brackets reduces SCF
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5. Type of Connections
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6. RPS 3 Points
A) Parametric study of type 1 connection for SCF
Sectional properties as per IS code
Applied loading as per beam design
Connection matrix
Connection design check for reinforcements
Considered non dimensional factors for parametric study
ABAQUS modeling and results
Linear regression equation development and check
Conclusions
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7. RPS 3 Points
B) Parametric study of type 1 connection for SCF
Specimens for cyclic behavior
Applied SAC loading protocol
Nonlinear cyclic behavior analysis results of ABAQUS
Conclusions
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8. SCF factor
• When an engineering component is being subjected to fluctuation loads, its
life is adversely affected because premature failure takes place through the
surface
• Fatigue is a phenomenon featured by the decay of the member’s strength
progressively leads to the appearance of cracks and eventually sudden and
catastrophic failure of the member
• Many factors control fatigue life of welded joints. Joint type, joint loading and
detailing of the joint are among the most critical factors that must be
considered. The type of the loading depends mainly on the type of the
structure.
• The localized peak stresses are defined as the nominal stresses multiplied by
stress concentration factor (SCF).
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9. • Hot spot stresses are usually defined as the maximum or peak
geometric stresses that occur where cracks would initially be
nucleated
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10. 1.5 Nominal stresses
• The nominal stresses are the maximum stresses that develop in the member
when being subjected to forces.
• Theses stresses are based on the elastic behavior of the member and derived
from the basic beam theory. Due to weld components, stress raisers are not
considered in normal stress calculation, Determining the nominal stresses is
a straightforward task.
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11. Type of connections
Type 1
Type 2
Type 3 Type 4
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12. Study of building under EQ loading and member selections
For the selection of section for the research study the real geometrical
building with real earthquake loading has been selected and has been
designed according to IS 800 : 2007
Building is designed in STAAD Pro.
The bottom part of building at plinth and below plinth is of RCC
Clear height of building is 4m
One direction the moment frame and in another direction the braced frame
with shear connections has been designed.
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13. geometry of building
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14. Loading consideration
• Earthquake loading has been considered as per IS 1893 : 2016 part 1.
• The building is considered in zone 3 type with damping of 2%.
• Z = 0.16, R = 4 as per IS 1893:2005 part 4, I = 1
• Dead load of 150mm thick slab and outer peripheral brick wall load has been
considered.
• Live load of 4 kN / m2 considered for medium industrial usages as per IS 872
part 2
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15. Load combinations for plastic steel design of steel structures as per IS 1893
part 4 cl. 7.3.1
• 1.7 DL + 1.7 LL
• 1.7 DL + 1.7 EQX
• 1.7 DL – 1.7 EQX
• 1.7 DL + 1.7 EQZ
• 1.7 DL – 1.7 EQZ
• 1.3 DL + 1.3 LL + 1.3 EQX
• 1.3 DL + 1.3 LL – 1.3 EQX
• 1.3 DL + 1.3 LL + 1.3 EQZ
• 1.3 DL + 1.3 LL – 1.3 EQZ
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16. Sectional properties
• All main beams were assigned with IPE300 / NPB300 as per
IS 22778:2004 code for parallel beam sections.
• All secondary beams were assigned with NPB 140
• All columns are provided with HE200A
• Fy = 250 Mpa with Fu = 420 Mpa material properties has been
considered in the design
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17. STAAD model of building
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18. Design output
and Unity check
• Load case 1.3 DL + 1.3 LL –
1.3 EQX is governing in the
design.
• So max end moment and
shear for which the connection
should be designed is as
follows
• Mu = 80 kN.m and Vu = 84.01
kN
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19. Connection design
• Type 1 & Type 2 Connection design
• For bending A = 2 * 150 mm (width of beam flange) = 300 mm2
• Ixx = 2 x 150 x (150)^2 = 6.75 x 10^6 mm4
• Z = Ixx / Y = (6.75 x 10^6) / 150 = 45 x 10^3
• Normal stress = 4 kN / 300 mm = 0.013 kN / mm
• Bending stress = (80 x 10^3) / (45 x 10^3) = 1.77 kN / m
• Vector sum of both stresses = 1.77 kN / m
• Weld Size = (1.77 x 10^3) / (510 x (1.73 x 1.25)) = 7.514 < 10.7 (flange thickness of IPE300 beam)
• So full flange will be grove weld with may welding access hole may be provided.
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20. • For Shear
• Dimension available = 300 – 10.7 x 2 -15 = 263.6 let’s 200 mm
• Weld size = 84 x 10^3 / (0.7 x 2 x 260 x (510 / (1.73 x 1.25)) = 0.979 mm
• So minimum 5mm filet weld size is adopted.
• Column check for stiffeners
Check =0.4 √ (Af / 1.1) = 0.4 x √ ( 150 x 10.7) / 1.1 = 15.27 > 10 mm = tfc
• Hence the column stiffeners is required for sufficient rigidity
• K = tfc + twc = 10 + 6.5 = 16.5
• Local web yielding
• Pbf = Fwc x twc x (5K + tfb) / 1.1
= 250 x 10 x (5 x 16.5 + 10.7) / 1.1
= 211.81 kN
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