[Announce-test] Payload possibilities: Collapse Simulation of Shear-Dominated Reinforced Masonry Wall Systems

[announce-test at designsafe-ci.org]

Payload possibilities: Collapse Simulation of Shear-Dominated Reinforced
Masonry Wall Systems

As part of a project aiming to obtain necessary experimental data for
understanding the behavior of reinforced masonry walls, project PI Benson
Shing and his team will be conducting shake table tests at the UC San Diego
experimental facility, starting in April 2018. There are excellent
opportunities for payload experiments, and Shing encourages NHERI
researchers to consider taking advantage of this large-scale test.
Project Summary

Seismic design codes have to ensure that buildings have a low probability
of collapse in the event of a severe earthquake. To develop such standards,
the ability to assess the collapse margin ratios of building systems
designed according to given specifications is of critical importance. Under
severe seismic forces, reinforced masonry (RM) wall structures might
develop complicated nonlinear behavior involving interaction between steel
and masonry. Furthermore, the interaction of structural walls with other
elements in a building system could lead to nonlinear behavior and collapse
mechanisms that were not anticipated in design, including behavior
dominated by diagonal shear cracks. The ability of analytical models to
capture these mechanisms and interactions is essential to have an accurate
assessment of the collapse margin ratio of a building. The main aim of this
project is to obtain necessary experimental data to understand the behavior
of RM wall structures to the point of collapse, and to use the data to
advance and validate refined as well as simplified analytical modeling
methods.

In this project, experimental and numerical studies will be carried out to
quantify: (1) the influence of wall flanges on the shear strength and
ductility of RM walls; (2) the influence of the coupling forces introduced
by horizontal diaphragms in a building on the strength and deformation
capability of the structural system; and (3) the influence of non-seismic
load carrying walls and columns on the drift capacity and collapse
resistance.
Shake-Table Tests

For the experimental study, two full-scale RM wall systems have been
scheduled to be tested to collapse on the outdoor shake table at the UC San
Diego NHERI site. They are identified as Specimens 4 and 5 in the research
proposal. As shown in Figures 1 and 2, these wall systems have different
levels of complexity to examine the influence of walls perpendicular to the
direction of the seismic forces on the performance and collapse resistance
of a wall system.  Both specimens are one-story tall. Each specimen will be
subjected to a sequence of earthquake ground motion records of increasing
intensities till collapse. During a test, cracks developed in the walls
will be marked and recorded, the deformation of the walls and reinforcing
bars will be monitored with displacement transducers and strain gauges, and
the accelerations of the specimen at the roof and base levels will be
measured with accelerometers. After each test with an earthquake ground
motion, the specimen will be subjected to white-noise excitation to
identify any change in the natural frequencies of the structure.
Figure 1 — Plan and elevation views of Specimen 4 Figure 2 — Plan and
elevation views of Specimen 5

The tests are scheduled to be carried out in the time period between April
and October 2018. The test schedules for the two specimens are shown in
Figures 3 and 4.
Figure 3 — Test schedule for Specimen 4 (April 2, 2018 - May 31, 2018) Figure
4 — Test schedule for Specimen 5 (August 1, 2018 - October 31, 2018) Payload
Project Opportunities

The shake-table tests provide payload research opportunities, which could
be supported by the NSF. Examples of possible payload projects include the
deployment and validation of innovative sensing and measuring technologies
as well as system identification techniques for damage assessment.
Interested researchers may contact Dr. Benson Shing, the project PI, at
pshing at ucsd.edu for any information needed for their payload project
planning and proposals to the NSF.

Collapse Simulation of Shear-Dominated Reinforced Masonry Wall Systems
<https://www.nsf.gov/awardsearch/showAward?AWD_ID=1728685&HistoricalAwards=false>
P. Benson Shing, PI
Department of Structural Engineering
University of California, San Diego
Email: pshing at ucsd.edu
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