Baltimore Bridge Disaster, Decision Patterns & more …
Authored by John Fitch (PPI Course Presenter and Principal Consultant)
In a sense, any previously made decision, whether successful or unsuccessful, can serve as a pattern/template to jump-start the analysis for a current decision. Any information object associated with the decision may also be used to inform a current choice – criteria, alternatives, performance estimates, risks, derived requirements, analysis tasks, or implementation tasks.
However, experience has shown that the greatest value generated by the use of a decision pattern lies in the decisions (questions to be answered), the relationship among decisions (DBS structure), and the criteria pattern for each decision.
A decision pattern enables timely, proactive identification of important project decisions and reduces the risk that a critical decision will be overlooked or discovered late in the project. Overlooked decisions will get the “leftovers” of resource and performance budgets that have been consumed by other choices and often lead to loss of stakeholder value (and goodwill) through dropped features or non-compliant performance.
Each decision in the pattern is typically given a short title (often dropping the implied term “Choose” for the sake of brevity) and a more complete scope description expressed as ... Read more (26-minute read)
In the early hours of a seemingly ordinary Tuesday, the city of Baltimore, USA was struck by a tragedy that would affect the nation. The Francis Scott Key Bridge, a vital connector in the region’s transportation network, met a catastrophic fate as it collapsed into the Patapsco River following a collision with the cargo ship Dali. The incident claimed the lives of six individuals, left several others injured or missing, and raised profound questions about the structural integrity and safety of our infrastructure.
A Detailed Account of the Unfolding Tragedy
The cargo ship Dali, a massive vessel measuring 300 meters (985 feet) in length, issued a distress call moments before the collision, indicating a loss of power. Despite attempts to regain control, the ship struck the bridge at a speed of approximately 14.5kph (9 mph), causing a significant section of the 2.6 km long (1.6 miles) structure to collapse into the water below. At the time of the collision, eight construction workers were on the bridge, engaged in routine maintenance work, filling potholes on the span. The rapidity of the collapse left little time for escape, leading to a tragic loss of life and a desperate search for survivors.
Investigations and Structural Integrity Concerns
The National Transportation Safety Board (NTSB) swiftly initiated an investigation to uncover the precise cause of the collision and the subsequent bridge failure. The focus has been on recovering data from the ship’s electronics and examining the structural integrity of the bridge. Preliminary findings suggest that the bridge, despite being a relatively modern structure, may not have been equipped to withstand the impact of a vessel as large as the Dali.
The Francis Scott Key Bridge, built in the 1970s, was designed with certain safety features to protect against collisions. Modern bridges are typically constructed with protections for the piers or columns that support them, such as “sacrificial dolphins” or artificial islands that prevent ships from reaching the bridge piers. However, the sheer size and velocity of the Dali may have ... Read more (5-minute read)
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Answered by Robert Halligan (PPI Managing Director and Course Presenter)
The aim is to maximize the difference between the risk-reduction benefit of verification of satisfaction of the requirement and the cost of achieving that benefit, giving an optimum verification requirement that drives verification design (how we will verify). The optimum verification requirement is usually best decided upon by discussion by a group of three engineers experienced in both verification and development, although a rigorous method also exists.
Non-functional requirements are those in sections 4.1, 4.2, and 4.5 to 4.10 of a well-structured system requirements specification. They are all requirements engineering ... Read full answer (1-minute read)
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7 个月Very important