Design for Disassembly: Towards the resilient and sustainable ABC of the future
Sebastian Varela, Ph.D.
Structural Engineer III
Freese and Nichols Inc., Fort Worth, Texas
1
Emerging Cu-Al-Mn (CAM) Shape Memory Alloy (SMA) Recently developed by
researchers in Japan
Easier to machine
Lower material cost
Still work in progress: low yield strength and hysteretic energy dissipation, production of large diameter bars
4
Design for Disassembly (DfD)
5
Extraction of
natural resources
Processing into
materials
Assembly into
bridges
Bridge use
Waste for
dumping
Demolition
Extraction of
natural resources
Processing into
materials
Assembly into
bridges
Bridge use
Waste for dumping
(minimal)
Disassembly
Reuse
Objectives
6
Study viability of superelastic CAM SMA + ECC for bridge columns: 0.4% permanent drift @ 12% max drift in CIP col
Utilize advanced materials to mitigate bridge damage and permanent drift: full post-earthquake functionality with minimal or no repairs
Develop and test resilient and earthquake-resistant replaceable plastic hinge elements, connections, and bridge columns and systems
Determine the influence of reusing column components: DfD
Key results
10
Japan seismic design specifications limit permanent drift to 1%
Saiidi & Ardakani(2013): 1% can be safely accommodated by a wide range of RC bridges
Original
Reassembled
2-span bridge models (bridge 1&2)
12
CE bent
NR bent
NE bent
30’
30’
RC blocks Safety frame
Safety
columns
Shake table
Steel plates
PT deck
N
3’-7 1/2”
8’-3 1/2”
Assembly/disassembly time-lapse
13
https://www.youtube.com/watch?v=RBwIRGUn52k
Bridge 2 test video
14
https://www.youtube.com/watch?v=dsoYeRELhSo
Typical state of plastic hinges after testing bridge 2 (reassembled)
NE bent – North EPH
CE bent – South EPH 15
Permanent DriftsBridge 1 (original) – Run 4 (175% x DE):
16
BentMaximum
drift (%)
Permanent
drift (%)
NE 5.60 0.26
NR 5.68 0.18
CE 5.58 0.07
Bridge 2 (reassembled) – Run 7 (260% x DE):
BentMaximum
drift (%)
Permanent
drift (%)
NE 9.95 0.26
NR 8.95 0.15
CE 7.90 0.08
Conclusions Innovative concept for resilient and sustainable bridges
was successfully developed and tested dynamically on ¼ scale single column and 2-span bridge models
The advanced materials and detailing result in minimal damage and permanent column drifts: increased functionality after strong earthquakes
The new system facilitates reuse of components: mitigate environmental impact
The system has the potential of expediting and facilitating maintenance, repair, and upgrade of elements: ABC
18
Thank you! Questions?
19
http://wolfweb.unr.edu/homepage/saiidi/NSF-PFI/index.html
Top Related