Energy Absorbing Beam-Column Connections
BEB801 – Project 1
Keagan Leamy n8329559
Presentation Overview
• Problem Overview
• Research Background• Concrete Connection Types
• Energy Dissipation Devices
• Proposed System• Model
• Loading
• Results
• Conclusion
Problem Overview
Beam-Column connections are vulnerable locations in a structure, especially under seismic loading.
𝐹 𝑡 = 𝑀 𝑢 + 𝐶 𝑢 + 𝐾 𝑢
Dynamic Energy = Energy to Vibrate Structure + Energy absorbed + Energy to deform structure
Aim to increase energy absorbed, reducing energy to vibrate and deform structure
Cyclic Loading
Boundary Conditions used for Seismic Loading, Cantilever
Column (Xue & Zhang, 2014)
Concrete Connection Types
• Monolithic Cast-In-Place
• Precast
• Ductile Connection
• Moment Connection
• Composite Beams
Monolithic Cast-In-Place
Example Reinforced Concrete Connection Geometry and
Steel Layout (Li & Pan, 2004)
Monolithic Cast-In-Place
Typical Failure mode and Flexural Cracks of a Monolithic Connection
(Parastesh, Hajirasouliha, & Ramezani, 2014)
Flexural Cracks began to form in both column and beam at half theoretical ultimate load
Precast - Ductile
Example Precast Ductile Connection Geometry and Steel
Layout (Khaloo & Paratesh, 2003)
Precast - Ductile
Typical Failure mode and Flexural Cracks of a Precast
Ductile Connection (Khaloo & Paratesh, 2003)
Connection prevented
crack propagation
from beam to column
Precast - Moment
Example Precast Moment Connection Geometry and Steel
Layout (Parastesh, Hajirasouliha, & Ramezani, 2014)
Precast - Moment
Typical Failure mode and Flexural Cracks of a Precast Moment
Connection (Parastesh, Hajirasouliha, & Ramezani, 2014)
Cracks occurred at connection zone, preventing flexural cracks to form in beam
Composite Beams
Example Composite Beam Column Geometry and Steel Layout
(Xue & Zhang, 2014)
Composite Beams
Typical Failure mode
and Flexural Cracks of
a Composite Beam
Section (Xue & Zhang,
2014)
Severe Cracking due to
neutral axis being closer to
slab.
Performance very similar to
cast-in-place systems
Energy Dissipation Devices
• Friction Damper
• Shear Links
• Viscoelastic Damper
Energy Dissipation Devices
Idealised Hysteresis Loops of Energy Dissipation Devices (Constantinou, Soong, & Dargush, 1998)
Friction Damper
Prototype Friction Damper (Morgen & Yahya, 2004)
Designed to aid with gap
opening behaviour of post
tensioned pre cast beams.
Increased energy dissipation of
specimen significantly.
Friction Damper
Simplified Numerical Model for Friction Damper (Valente,
2013)
Energy Dissipated by
structure decreased as
energy dissipation was
concentrated in device.
This reduced the plastic
demand of the structure.
Shear-Links
Schematic Diagram of an Aluminium Shear Link Included
into a Chevron-type OCBF (Rai & Wallace, 1998)
Viscoelastic Damper
Picture of Viscoelastic-Wall Dampers (Liu, Wang, & Ren,
2015)
Proposed System
Proposed System
Proposed System - Control
Parameter Value
Stiffness: 𝒌 =𝟏𝟐𝑬𝑰
𝑳𝟑 = 0.527 × 106𝑁/𝑚𝑚
Mass (kg) 6932.2kg
Circular Frequency of Vibration: 𝝎 =
𝒌
𝒎(rad/sec)
= 8.72𝑟𝑎𝑑/𝑠𝑒𝑐
Period of Vibration: 𝑻 =𝟐𝝅
𝝎(sec) 0.72sec
Frequency: 𝒇 =𝟏
𝑻1.4 Hz
Proposed System - Control
-1.5
-1
-0.5
0
0.5
1
1.5
0 1 2 3 4 5 6 7
Forc
e (
kN
)
Time (s)
Force vs Time Graph
Proposed System - Control
Proposed System - Device
Variable Parameter Value
Breadth b (mm) 450
Thickness d (mm) 40
Length L (mm) 270
Mass (kg) 38.151
Young’s Modulus E (Mpa) 200 000
Second Moment of
Area 𝐼 =𝑏𝑑3
12(𝑚𝑚4)
2.4 × 106
Axial Stiffness=𝐴𝐸
𝐿(𝑁/𝑚𝑚)
13.333 × 106
Lateral Stiffness=12𝐸𝐼
𝐿3(𝑁/𝑚𝑚)
0.293 × 106
Proposed System - Device
Proposed System - Results
Proposed System - Results
-15
-10
-5
0
5
10
15
0 1 2 3 4 5 6 7
Dis
pla
cem
ent
(mm
)
Time (sec)
Comparrison in Displacement vs Time with and without Device
Control Device
Proposed System - Results
-30
-20
-10
0
10
20
30
-0.4 -0.3 -0.2 -0.1 0 0.1 0.2 0.3 0.4
Forc
e (
kN
)
Displacement (mm)
Hysterises Loop For Device
Conclusion