Expertly Speaking

Structural Analysis of Annealed Glass Windows


Brandon Erickson, P.E., S.E., Structural Engineer

Case Synopsis: The plaintiff, a teenage boy, was preparing for practice with his high school wrestling team when he suffered a serious injury to his arm. The injury occurred while he and his teammates were moving wrestling mats, which were rolled and stacked in the school cafeteria when not in use. In the course of endeavoring to move the top-most rolled mat, the plaintiff’s arm broke through one of the adjacent windows causing permanent damage to his arm.

Expert Analysis: In his deposition the plaintiff claimed to have only “touched” the glass window, which then reportedly shattered and broke, allowing his arm to be cut on the shards of glass as it passed through the plane of the broken window. An examination of the window wall revealed that the glass used in the windows was annealed, not tempered glass (often referred to as safety glass). Plaintiff’s counsel argued the presence of safety glass would have prevented injury to his client. The school’s defense counsel argued that notwithstanding the presence of annealed glass, the window would not have broken under the conditions described by the plaintiff, suggesting that instead the plaintiff was “roughhousing” while leveraged against the window to move the mat. Defense counsel requested a structural engineering analysis of the window system to quantify the force required to cause the glass panes to break.

Fortunately, the remaining original windows in the cafeteria wall were still intact and available for diagnostic testing. A custom-designed and constructed testing mechanism was conceived and employed to quantify the breaking strength of the windows. All elements were precisely replicated to the same conditions that occurred during the incident, including a prosthetic hand and testing apparatus to move it with similar force and angle. Prior to conducting the physical tests on the windows, engineering calculations were performed to predict the force at which the windows would break. The calculations were based upon the material properties of the glass chards collected from the broken window, which was deemed identical to the unbroken windows that were tested. These calculations served as a means of comparison with the forthcoming test data, and aided in the development of the testing mechanism to ensure it was capable of delivering sufficient force to the windows.

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Staging Collisions: Can Physical Evidence Determine Intent of Parties Involved?


R. Scott King, BSME, Principal Automotive / Mechanical Engineer

A good friend of my consistently preached at educational seminars across the country that “Collision reconstruction is application of the laws of physics to physical evidence left as a result of a collision.” He also encouraged his listeners to trifurcate their traffic collision cases into their basic components: The vehicle, roadway, and driver. Indeed, these mantras formed the framework within which virtually all his collision reconstruction analyses were performed. However, it has always been understood that physical evidence (including vehicle event data) often do not enable a reliable understanding of the intent of the parties involved in a collision.

Recently, five people from the New Orleans area were indicted on federal fraud charges for alleged staged collisions with commercial motor vehicles. The accused actors in these alleged schemes not only planned and executed the collisions but utilized at least one attorney to bring the knowingly fraudulent claims and a small network of medical professionals to create false and inflated medical records. In each case, reconstructing the collisions in the typical, conventional manner allowed reconstruction engineers to establish the pre-crash vehicle speeds, the collision dynamics, and the forces involved. Bio-medical engineers could also evaluate the claimed injuries in terms of those collision forces. All this engineering led to whatever conclusions the physical evidence and science permitted; however, it was only through a variety of “red-flags” that insurance investigators uncovered a pattern.

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Seatback Strength


John R. Yannaccone, P.E., Sr. Mechanical Engineer

In 1966, the National Traffic and Motor Vehicle Safety Act established a set of safety standards for motor vehicles and established the National Highway Safety Bureau, now known as the National Highway Traffic Safety Administration (NHTSA). The Federal Motor Vehicle Safety Standard (FMVSS) 207, which focuses on the strength of vehicle seats, was among the standards established. FMVSS 207 includes a requirement for the strength of the seatback, which is tested by applying a rearward force near the top of the seatback and limits the post-test deformation after the seat is subjected to a specified moment or torque (a force applied at a distance). For decades, engineers have argued the FMVSS 207 requirements are inadequate for the safety of occupants in rear impacts.

When a vehicle is struck from behind, the seatback provides the primary means of restraint to the occupant. When the seatback deforms rearward, it can result in several issues. Once the seat reaches around 45° recline angle, it starts to lose the ability to retain the occupant and they begin to slide up the seatback. This can result in the occupant impacting the rear seat with their head or being ejected from under the seatbelt, exposing the occupant to a wide range of injuries. In addition to affecting the front seat occupants of the vehicle, this deformation of a seatback can expose backseat occupants to potential injuries.

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multi-car-accident

Reconstruction of Multi-Vehicle Collisions


Justin P. Schorr, Ph.D., Principal Collision Reconstruction / Transportation Engineer

Multi-vehicle collisions, sometimes involving dozens of vehicles, typically occur during periods of adverse weather conditions such as snow, ice, and/or fog (some may recall the recent 20+ vehicle collision in Pennsylvania). When these collisions occur on high-speed, limited-access highways, there can be severe consequences as a result of the multiple impacts (at the time of this writing it has been reported that there were 2 fatalities and over 35 people sent to the hospital as a result of the aforementioned pile-up in Pennsylvania). However, from a reconstruction standpoint, with so many vehicles involved, how does one define the dynamics of the collision?

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Fighting Fury with Forensics


Laurence R. Penn, Forensic Animation/Video Specialist

If you’re a regular streaming TV subscriber, you’ve probably heard of or even seen the documentary on Netflix, “Don’t F**K with Cats: Hunting an Internet Killer.” Likely, you don’t remember the events that took place in 2010; but, as the title undoubtedly suggests, what transpired and is expertly told in the original series is disturbing, unsettling, and saddening to say the least. This article will delve into the story, revealing some of the twists exposed along the way, so consider this to be your spoiler alert.

Facebook and YouTube were about five years old at the time, and this is around when social media posts, photos and videos began being coined as “going viral.” One such video was that of an unidentified male fatally harming kittens. As the video spread, a group started to band together online to try and identify the individual to put them to justice for their utterly heinous act. The team used clues evident in the background of the video footage such as doorknobs, electrical outlets, furniture, and even appliances to locate geographically where the videos were filmed. Eventually, another video surfaced of the same individual performing more atrocious violent acts on poor, defenseless felines. This, of course, drives the online group to double and triple their efforts in identifying the monster before he moves on to harm any other creature or, as history has proven, person. Various clues left by the animal killer leads the online team to discover his name and numerous social media fan pages containing photos of himself posing in exotic places all over the world, supposedly as some highly successful and handsome male model. Yet, something about some of the photos isn’t right. As more and more information is uncovered, and with the help of some of the photos, the elusive and always changing location of the man is identified, just moments too late, by architecture and roadways in the photos and GPS data contained in the metadata.

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Let’s Find the Contractor


Kenneth A. Kandrac, CFI, Fire Cause and Origin Expert

An attached single-family dwelling along a Jersey Shore river was the scene of a major structure fire. The insured’s college age son was in a third-floor room studying. While in a second-floor living room, the insured observed smoke flashing past the windows. Within a few minutes a first-floor smoke detector sounded. Going to the first-floor, the insured observed fire venting from the laundry room, and within seconds he was driven from the first-floor to the exterior of the home. He immediately called for his son, who quickly responded, but could not exit via the interior stairway and was forced to jump from a second-floor window.

The investigation revealed a well-involved fire in an electric clothes dryer. Fire patterns on the dryer were consistent with an extensive lint buildup. Continuing evaluation of the fire patterns and fire extension within the first-floor showed an unusual configuration for the routing of the metal exhaust duct for the dryer vent. The builder had decided to route the exhaust from the laundry room near the front of the structure to the rear wall adjacent to a parking lot, an extended run for metal duct.

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