United States District Court, N.D. Georgia, Atlanta Division
OPINION AND ORDER
WILLIAM S. DUFFEY, JR. UNITED STATES DISTRICT JUDGE
matter is before the Court on Defendants Terex Corporation
(“Terex Corp.), Terex South Dakota, Inc. (“Terex
SD”), and Terex Utilities, Inc.'s (“Terex
Utilities”) (collectively, “Terex” or the
“Terex Defendants”) Motion for Partial Summary
Judgment Regarding Plaintiff's Claims 
(“Motion for Summary Judgment”).
a products liability action stemming from the failure of a
2002 Terex Hi-Ranger XT 60/70 boom, Serial No. 2021020554
(the “Subject Boom Truck”), an aerial lift
device. Terex XT aerial devices are commonly utilized by tree
trimming companies. The Subject Boom Truck consisted of a
lower boom, upper boom, and bucket, as depicted in the
April 9, 2014, Plaintiff Jeffrey Gaddy
(“Plaintiff”) was in the bucket of the Subject
Boom Truck when the lower boom stub fractured, causing
Plaintiff to fall to the ground. Plaintiff suffered spinal
injuries resulting in paraplegia. Plaintiff claims Terex
negligently manufactured and designed the Subject Boom Truck,
and that it failed to warn him of certain dangers.
Subject Boom Truck was part of Terex SD's XT aerial
device line, which consisted of XT52, XT55, XT58, and XT60
aerial lifts. (Defs.' Statement of Undisputed Material
Facts [317.2] (“DSMF”) ¶7; Pl.'s Resp.
[340.1] (“R-DSMF”) ¶ 7). The line, beginning
with the XT52, was first designed by Terex S.D. in 1996. The
number following the XT designation represents the maximum
height that the bucket platform can reach when fully
extended. The Subject Boom Truck was an XT60, which was
originally designed in 1999. (DSMF ¶5; R-DSMF ¶ 5).
American National Standards Institute (“ANSI”)
sets forth standards for the design of vehicle-mounted
elevating and rotating aerial devices, like the Subject Boom
Truck. (DSMF ¶8; R-DSMF ¶ 8). Section 4 of ANSI
A92.2 (2001) (the “ANSI Standard”) sets forth the
design requirements that apply to the Subject Boom Truck,
including structural safety factors. (See DSMF
¶ 9; R-DSMF ¶ 9). Regarding the Subject Boom
Truck's structural safety factors, the ANSI Standard
provides that “[t]he calculated design stress shall be
based on the combined rate load capacity and weight of the
support structure. For ductile materials, the design stress
shall not be more than 50% of the minimum yield strength of
the material.” (DSMF ¶ 10; R-DSMF ¶ 10).
Thus, the steel boom of the Subject Boom Truck, a ductile
material, needs to meet a safety factor of 2.0 to comply with
the ANSI Standard. (See id.).
standard further requires that, in designing the aerial
device, a manufacturer must consider “stress
concentrations, dynamic loadings, and operation of the device
at ¶ 5 degree slope.” (DSMF ¶ 11; R-DSMF
¶ 11). The ANSI Standard does not provide any specific
direction as to how these three factors should be considered,
allowing manufacturers to exercise their discretion in
considering them. (DSMF ¶¶15-16; R-DSMF
claims that the calculated design safety factors for the
upper and lower booms of the Subject Boom Truck exceeded the
2.0 safety factor in the ANSI Standard. (DSMF ¶13).
Specifically, for the specified minimum yield strength of 70,
000 psi (pounds per square inch), Terex claims the lower boom
stub where the Subject Boom Truck failed had a calculated
design safety factor of 4.0. (Id.). Plaintiff
contends these figures are estimated calculated stresses, and
that Terex knew, pre-production, that its actual stress
numbers far exceeded those estimations. Plaintiff argues
that, had Terex calculated safety factors based on the actual
stresses in its design, its boom would, by a wide margin,
have failed to have a 2.0 safety factor. (See R-DSMF
time the Subject Boom Truck was designed, Terex SD's
calculated design measurements were independently verified by
Terex SD's Director of Engineering, Jon Promersberger, to
ensure their accuracy. (DSMF ¶ 20; R-DSMF ¶ 20).
Plaintiff's expert, Nathan Morrill, P.E., stated that any
design that meets a calculated design safety factor of 2.75
adequately considers the factors set forth in the ANSI
Standard and otherwise complies with the ANSI Standard
requirements. (DSMF ¶¶ 18, 21; R-DSMF
Strain Gage Testing and Internal Standards
1999, as part of its analysis and verification of the XT60
design, Terex S.D. retained All Test & Inspection, Inc.
(“All Test”) to conduct strain gauge tests on the
Subject Boom. (DSMF ¶¶ 21-22, R-DSMF ¶¶
21-22; see also Pl.'s Statement of Additional
Material Facts  (“PSAF”) ¶¶ 25,
29, 45-46). Strain gauge testing measures how much a
material changes shape when a force is applied on the object,
and it is utilized to determine measured, or actual, stresses
in a design. (DSMF ¶ 22; R-DSMF ¶ 22; PSAF ¶
contends that the strain gauge testing on the XT60 boom
showed that Terex's theoretical calculations did not
adequately account for the actual stresses in the boom.
Although the hand-calculated theoretical stress in the boom
failure area, an area of stress concentration, was 17, 625
psi, (PSAF ¶ 40; Defs.' Resp. to PSAF  R-PSAF
¶ 40), All Test's strain gauge testing showed that
the stress in that area was actually 35, 300 psi, (PSAF
¶ 41; R-PSAF ¶ 41).
contends that Terex's internal design safety standard
required that its booms meet a 2.0 safety factor based on the
actual, rather than calculated, stresses. (PSAF ¶ 44).
Terex argues that it had an internal safety factor of 2.75
for calculated stress, which it claims accounted for measured
stresses, dynamic loading, and a 5 degree slope. (R-PSAF
points to several of All Test's reports to Terex S.D.
regarding strain gage testing of multiple previous boom
models. The reports state that the object of the tests was to
test for compliance with the ANSI Standard, and that the
“structural safety factor used to evaluate the stress
levels was 50% of the minimum material yield strength,
” that is, a 2.0 safety factor. The test reports stated
that certain “areas do not meet the requirements called
for in [the ANSI Standard].” (PSAF ¶¶ 21-24).
Plaintiff presents evidence that, because of these reports,
Terex redesigned the failing areas of these booms and
retested them later. (PSAF ¶¶ 21-23). A Terex S.D.
internal report states that “[m]easured stresses should
not exceed 50% of the material's yield stress.”
(PSAF ¶ 24). Terex S.D. presents evidence that this
statement appears under the header “Objective”
because it was Terex SD's goal to “go above and
beyond what is required by ANSI.” ([318.27] at
Subject Boom Truck was manufactured in September 2002. (DSMF
¶ 31; R-DSMF ¶ 31). The manufacturing process
begins with the purchase of component parts, each of which is
inspected for compliance with the purchase order and part
number. (DSMF ¶¶ 34, 36-37; R-DSMF ¶¶ 34,
36-37). The component parts are welded at Terex SD's
plant in Huron, South Dakota, (“Huron Plant”),
then delivered to Terex SD's plant in Watertown, South
Dakota (“Watertown Plant”) for final assembly.
(DSMF ¶¶ 36, 42; R-DSMF ¶¶ 36, 42).
Following assembly, Terex S.D. conducted a final inspection,
which included load testing to twice the rated load limit of
the Subject Boom Truck. (DSMF ¶ 44; R-DSMF ¶ 44).
On or about October 4, 2002, the Subject Boom Truck was
certified compliant. (DSMF ¶¶ 43-44; R-DSMF
the main structural components of the lower boom stub where
the subject failure occurred was a lower boom tube,
identified as part no. 444195. This boom tube was designed as
a hollow rectangular steel beam with a length of 113 inches,
and was to be manufactured of steel with a minimum yield
strength of 70, 000 psi. (DSMF ¶¶ 32-33; R-DSMF
¶¶ 32-33). At the time the Subject Boom Truck was
manufactured, Terex S.D. ordered part no. 444195 from
Defendant Joseph T. Ryerson & Son, Inc.
(“Ryerson”). (DSMF ¶ 34; R-DSMF ¶ 34).
Each purchase order submitted to Ryerson specified that part
no. 444195 was to be cut to a length of 113 inches and was to
consist of steel with a minimum yield strength of 70, 000
psi. (DSMF ¶ 35; R-DSMF ¶ 35). Part no. 444195 was
the only component on the Subject Boom Truck ...