Hybrid Masonry Seismic Structural Systems:
Material Characterization
Alejandro Zepeda, Texas A&M University, alejandro_zepeda@neo.tamu.edu
REU Site: University of Illinois at Urbana Champaign
PI: Dr. Daniel Abrams, d-abrams@illinois.edu
Mentor: Timothy A. Gregor, gregor2@illinois.edu
What is Hybrid Masonry
• Hybrid Masonry is a new
structural design for earthquakeresistant buildings proposed by
David Biggs at the 10th North
American Masonry conference.
• Hybrid Masonry is a structural
system that incorporate a
reinforced masonry panel within
a steel frame.
• There are three types of Hybrid
Masonry: Type I, Type II, Type III
• In Type I hybrid masonry, steel
plates ( connector plates/ fuse
plate) will connect the masonry
panel to the steel frame.
• In Type II and Type III, headed
studs will be welded to the steel
beam in order to transfer shear
forces to the masonry panel.
Additionally, vertical
compressive forces will be
transferred to the masonry panel
since the gap between the
masonry panel and the beam is
removed from Type II and III.
• Hybrid masonry was designed
for low to mid rise buildings.
Several buildings in the eastern
United States have been built
using this new concept.
Material Testing
• Material testing is an integral part of any research.
• Data from material testing will be used to verify material
properties and define computer models.
• Material testing was performed on all the construction
materials that make up a reinforced masonry wall: concrete
masonry unit, masonry prism, grout, and reinforcement bar.
• All test were performed in accordance with ASTM
specifications.
• Data processing, curing, and analysis followed the test.
• The test results were then compared with ASTM findings.
Reinforcement
Bar #4
Hybrid Masonry Detail (credit: IMI)
Research Team
•
•
•
•
University of Illinois at Urbana-Champaign: Exploratory
studies and large Scale Testing
University of Hawaii at Manoa: Connector plate/ fuses
plate testing
Rice University: Simulation Models
Ryan-Biggs Associates: Outreach and Education
600 Kip MTS uniaxial servo-controlled
hydraulic frame
External Sensor
(Extensometer)
Concrete
Masonry
Block
Sample
Cross
Sectional
Area (in2)
Peak
Compressi
ve Force
(lbs)
Stress
(psi)
1
34.9
151,040
4,328
2
34.8
155,000
4,450
3
34.8
142500
4,091
Grout
Sample
Cross
Sectional
Area (in2)
Peak
Compressi
ve Force
(lbs)
Stress
(psi)
1
9.375
55,588
5,929.38
2
9.1875
46,927
5,107.70
3
9.1875
50,980
5,548.84
Masonry Prism Sample
(Grouted)
Cross Sectional Area
(in2)
Peak Compressive
Force (lbs)
Stress (psi)
1
58.8
228,959
3,891
2
58.8
291,145
4,947
3
58.8
292612
4,972
Masonry Prism Sample
(Un-Grouted)
Cross Sectional Area
(in2)
Peak Compressive
Force (lbs)
Stress (psi)
1
34.8
107,000
3,072
2
34.8
91,091
2,615
3
34.8
137,749
3,955
• Six masonry prisms, three grouted and three un-grouted,
were constructed and tested using ASTM C1314
specifications.
• The prisms were tested with a 600 Kip MTS uniaxial servocontrolled hydraulic frame.
• A uniform axial compression force was applied to the prism
until failure occurred.
• An external sensor measured the prism displacement while
the internal load cell measured the compressive force.
• The data from the extensometer and load cell was used to
form load versus displacement and stress versus strain
plots.
• The prism compressive strength was calculated from the
net cross-sectional area and the peak compressive force.
• The grouted prism had greater values for compressive
strength which confirms previous grout and block
compressive strength data.
• Three concrete masonry units (CMUs) were tested for
compression strength.
• An axial compression force was applied to the blocks at a
rate of 8-19 psi per second.
• The peak compression force was recorded and the
corresponding stress was calculated using the net crosssectional area. The results were recorded in table format.
• The Hilsdor equations can be used to estimate the value of
the compressive strength of the masonry prisms.
Hilsdorf equation
• The results from material testing will be used to estimate
the flexural and shear strength of the reinforced masonry
panel and the overall behavior of the hybrid masonry
structural system.
• The panel strength is necessary to develop and design the
connector plates and also to design the steel frame that will
incase the masonry panel.
• Rice University who is working on the computer simulation
models will refer to the material testing data.
Further Information
• Number 4 rebar was tested using a 100 kip servo controlled
hydraulic frame.
• Four 2-1/2’ specimens were tested for yield strength and
ultimate strength.
• An external sensor was used to measure the displacement of
the specimen while an internal load cell recorded the
corresponding force.
• Stress strain plots were formed to evaluate the properties of
the rebar.
Grout
Sample
• All data collected from Material Testing was archived and
uploaded to the nees.org project page for future use.
• Data summary tables, load versus displacement plots, and
stress versus strain plots were created for prism and
reinforcement test. Summary tables were created for grout
and block testing.
Masonry Prism
External Sensor
(Extensometer)
Concrete Testing Apparatus
Future Usage
Testing Outcomes
𝑓′𝑢𝑑𝑡 + 𝛼𝑓′𝑗𝑡
𝜎𝑦 =
𝑓′𝑢𝑡
𝑓′𝑢𝑑𝑡 + 𝛼𝑓′𝑢𝑡
𝑡𝑗 /𝑡𝑏
𝛼=
4.1
• Three grout samples were prepared following ASTM C476
mixing specifications and prepared using ASTM C1019
specifications.
• After 28 days, the grout samples were tested in a similar
manner as the CMUs and the results tabulated.
For more information on hybrid masonry, please visit the
Hybrid Masonry Seismic Structural Systems project page at
nees.org, or please contact Dr. Abrams (PI) at
d-abrams@illinois.edu.
Literature Cited
Abrams 2011: Abrams, D., “NSF-NEESR Research on Hybrid
Masonry Seismic Structural Systems,” Proceedings of the 11th
North American Masonry Conference, Minneapolis, Minnesota,
June 2011.
Biggs 2007: Biggs, D.T., “Hybrid Masonry Structures,”
Proceedings of 10th North American Masonry Conference, St.
Louis, Missouri, June 2007.
Gregor 2011: Gregor, T., Fahnestock, L.A., Abrams, D.,
“Experimental Evaluation of Seismic Performance for Hybrid
Masonry,” Proceedings of 11th North American Masonry
Conference, Minneapolis, Minnesota, June 2011.
Johnson 2011: Johnson, G., Robertson, I.N., Goodnight, S.,
Ozaki-Train, R., “Behavior of Energy Dissipating Link
Connectors,” Proceedings of 11th North American Masonry
Conference, Minneapolis, Minnesota, June 2011.
Acknowledgements
I would like to thank Dr. Abrams for inviting me to UIUC, Tim
Gregor for guiding my research, Greg Pluta for being a great
NEES site host, Weslee Walton for keeping me organized. I
would also like to acknowledge the NSF for founding our
research through the George E. Brown Jr. Network for
Earthquake Engineering Simulation.
• Connector plate design and testing is being explored at The
University of Hawaii at Manoa.
• Two types of plates are under investigations: strong
connector plates and energy dissipating plates.
• The connector plates are exposed to cyclic loading until
failure occurs.
• The Hysteretic curve shows the load versus deflection.