The Tacoma Narrows Suspension Bridge Case Study

The Tacoma Narrows Suspension Bridge - Case Study Example The design also integrated piers along the bridge’s span for support. Additionally, incorporated in the design were several checking cables, as well as, devices proposed to be installed along the bridge’s spans to hold the deck down, preventing it from turning in the wind. Evident from the planning phase, the Authority and suspension bridge specialist, Moisseiff had the sole intention of constructing an affordable and safe bridge to benefit residents of Kitsap and Tacoma. However, the phase was not without flaws and ethical missteps. First, the authority turned down a bridge design previously proven safe, for a narrow suspension bridge design, never constructed before just because it was cheaper. The other design flaw was failure to take into account the actual wind force to which the bridge would be exposed. Additionally, during the planning phase, emphasis was placed on the structural components of the bridge. Of particular interest were the recommended open girders, which were later replaced with solid ones by the local building engineer during design execution. The plan was also flawed in regard to location selection for the bridge construction. The Tacoma Narrows; topography is highly susceptible to winds of high intensity, making it an unsuitable location to put up a suspension bridge (Pinto 221). Question #2 Qualitative risk matrix Likelihood Insignificant 1 Minor 2 Moderate 3 Major 4 Catastrophic 5 A(Almost Certain) M H H E E B(Likely) M M H H E C(Possible) L M M H E D(Unlikely) L M M M H E(Rare) L L M M M Level of Risk: (E)-Extreme Risk (H)-High Risk (m)-Moderate Risk (L)-Low Risk According to the chart above, the level of risk, rather obvious for the Tacoma Narrows Bridge, was high. This is because, the level of risk posed by the bridge necessitated formulation of a detailed action of plan on the way forward, in dealing with the issues arising when the bridge was still under construction. For instance, during construction the attaching t ie-down cables snapped and proved to be ineffective. The bridge was also swayed by the wind presenting critical danger, an aspect attributable to its light weight and its narrow nature. Therefore, the level of risk was undoubtedly high, even though it could not be termed as catastrophic at this early stage. However as time progressed there were indications that the bridge would collapse. This notion rose from the increased number of risk factors that were identifiable on the bridge. For instance, slight winds would make the bridge sway to great levels and even cause wave like oscillations, posing great danger to motorists. This was because; instead of the bridge allowing wind to pass, it was acting like a kite, trapping moving air with its flat sides. Another risk factor warranting the classification of TNB as a high risk structure was, the topography of the Tacoma Narrows which made the bridge weaker, since it lay directly across the path of the wind, thus exposing it to maximum im pact. The engineers also changed some of the recommended design elements thus increasing the structure’s probability of collapsing. All these were major factors that heightened the TNB’s risk level. Even though it was hard for individuals to notice all the risk aspects when the bridge was being built, the engineers should have identified the risk in the design, sighting of the bridge or