CENTERCORE STRENGTHENING
SYSTEM FOR UNREINFORCED MASONRY BEARING WALL BUILDINGS
The CenterCore strengthening system consists of a reinforced
grouted core placed in the center of an existing unreinforced masonry wall. The core is
provided by coring a vertical hole from the top continuously through the wall into the
existing footing or basement wall.
The core achieved by this oil-well drilling technique may be
four (100mm) to six (150mm) inches in diameter, depending on the thickness of the existing
unreinforced masonry wall and the strengthening required. The drilling is a dry process
with the debris removal handled by a vacuum and filter system that keeps the dust to a
minimum. Reinforcing steel is placed in the center of the hole, usually a #6 (#20m) to #9
(#25m) bar, and a polyester-sand grout is pumped from the top of the wall to the bottom
such that the core is filled from the bottom under pressure controlled by the height of
the grout.
The placement of the grout under pressure provided by the
height of the core, provides a beneficial migration of the grout into all voids adjacent
to the core shaft. The strong bonding of the grout to the inner and outer wythes of brick
provides a "homogeneous" structural element much larger than the core itself.
This reinforced "homogeneous" vertical beam provides strength to the wall with a
capacity to resist both in-plane shear and out-of-plane bending. Anchors for lateral ties
may be accomplished at the core for connecting roof and intervening floor diaphragms.
The main benefit of the CenterCore system to the structure is
a nondestructive strengthening of the bearing walls where strength is expected as opposed
to a secondary adjacent structure such as Shotcrete or steel frames. The advantage of the
CenterCore system to the owner is the minimal site/interior disturbance and no disfiguring
of the internal or external fabric to accomplish safe resistance to future ground shaking.
Malaga Cove Plaza, PVE, CA - This
historic landmark located in the City of Palos Verdes Estates was built using unreinforced
masonry. BQE utilized its innovative CenterCore technology to
strengthen the building without disturbing the current tenants.
Fullerton Police Department, Fullerton, CA
- This historic landmark building was designed to resist strong ground motions. The
design is currently in progress. A PML study was also performed.
City Hall Building, Fullerton, CA
- BQE Inc. was chosen by the City of Fullerton to retrofit the main City Hall
building. The contract was awarded based on our expertise in the field of seismic
strengthening and our well known state-of-the-art computer analysis capabilities. A PML
study of the building was also performed.
Jet Rag retail center, Los Angeles CA
- This famous retail center located at the 825 N La Brea Avenue was designed by
Keith Greco. For this project Keith choose to create an avante grade design featuring a
series of bombs thrusting through the windows. BQE Inc. did the structural design and
retrofit for the building. The design challenge was highly recognized by the engineering
community and earned a fourpage article in the Modern Steel magazine in Feb 1998. (See
Bombs Away)
Armani of Santa Monica, CA - Located
at 185 Pier Avenue in the City of Santa Monica, this historic building housed the famous
Armani store. BQE Inc. was responsible for the seismic retrofit of this historic landmark.
Malaga Cove Plaza, PVE, CA - This
historic landmark located in the City of Palos Verdes Estates was built using unreinforced
masonry. BQE utilized its innovative 
Fullerton Police Department, Fullerton, CA
- This historic landmark building was designed to resist strong ground motions. The
design is currently in progress. A PML study was also performed.
City Hall Building, Fullerton, CA
- BQE Inc. was chosen by the City of Fullerton to retrofit the main City Hall
building. The contract was awarded based on our expertise in the field of seismic
strengthening and our well known state-of-the-art computer analysis capabilities. A PML
study of the building was also performed.
Jet Rag retail center, Los Angeles CA
- This famous retail center located at the 825 N La Brea Avenue was designed by
Keith Greco. For this project Keith choose to create an avante grade design featuring a
series of bombs thrusting through the windows. BQE Inc. did the structural design and
retrofit for the building. The design challenge was highly recognized by the engineering
community and earned a fourpage article in the Modern Steel magazine in Feb 1998. (See
Bombs Away)
Armani of Santa Monica, CA - Located
at 185 Pier Avenue in the City of Santa Monica, this historic building housed the famous
Armani store. BQE Inc. was responsible for the seismic retrofit of this historic landmark.