The Hartford Arena, with a seating capacity of 5000 spectators was completed in 1973. While computer use is an integral part of design and analysis nowadays, the construction of the Hartford Arena involved one of the earliest applications of computers to the analysis of complex frame structures. The arena used only four columns to support the roof and this minimized obstruction for spectators. The roof was a three-dimensional truss structure about 3 m deep, and approximately 91m by 110 m, suspended about 25 m above the ground.
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On January 18, at 4:15 a.m. the roof of the arena collapsed onto the central court during a heavy snowfall. The collapse occurred in the middle of the night, missing the spectators who had packed the arena earlier in the evening, by a few hours. Failure investigations revealed the snow load at the time of the collapse was estimated to less than half the rated load of the roof. The design of the structural steel had several errors, attributed to an “ oversimplified computer analysis”. The engineers had heavily depended on computer analysis for the safety of the design. The stress analysis software neglected the fact that structural rods in compression buckle at a stress far lower than the yield strength of steel, which is the limit for rods in compression. The error could have been discovered by simply comparing the stress generated by the computer against the Euler buckling equation. The design engineers were negligent or incompetent. They subjugated their judgement to the computer. Lesson learned from the collapse was that, computer program validation should be routine due diligence. Engineers are responsible for verifying that the results obtained by using software are accurate, reliable and acceptable. The Engineer must have suitable knowledge of the engineering principles in the work being conducted and is responsible for the appropriate application of the principles.
An engineer should perform 5 tests when using commercial software. These tests include; dummy runs, approximate calculations, theoretical calculations, advanced methods and complete duplication.
Dummy Run – Performing calculations with known answers in order verify the values
Approximate Analysis – Create a simplified version of your project and see if the final values correspond to the original values
Theoretical Calculations – Perform calculations using the necessary formulas gathered during your engineering career/academia to validate the results
Advanced Methods – Create more advanced procedures to verify the values
Duplication – Recreate your project using different software to ensure that the original software was correct
The engineers working on the Hartford Arena neglected to carry out any of the aforementioned tests, and in turn, disregarded public welfare. The Code of Ethics subjects professional engineers to regard public welfare as paramount, otherwise, the engineer is acting in an unethical manner. Neglecting to ensure the accuracy of stress calculations on an arena that houses thousands of people is unethical to say the least.
The roof collapse becomes even more frightening after realizing that when the truss was put into place, there was significant deflection. The deflection was so large that the original window panels were not able to fit. One would hope that construction would be halted and the validation tests (which should have already been completed) would begin once the significant truss movement was detected. This was not the case and, therefore, the Hartford Arena collapsed.
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