[Name of the Writer]

[Name of Instructor]

[Subject]

[Date]

Bridge Collapse

Introduction

The I-35W Mississippi River Bridge was officially known as Bridge 9340. The bridge was long enough about 1907 foot and was serving Minneapolis for forty years. It was an eight- lane, steel truss arch bridge and situated across the Mississippi River in Minneapolis situated in Minnesota, United States. On 1st August, 2007, during an evening hour when it was a rush time. The Bridge collapsed and killed 13 people and injured 145 people Weeks, John A. III (2007). This Bridge was the busiest bridge of Minnesota. It carried 140,000 vehicles daily. According to reports, it was considered that there was a design fault, and collapse was the result of overweight which contributed the catastrophic failure. These types of bridges consist of steel frames of gusset plates. The plates are connected to each node of the bridge.

Discussion

“A half inch difference may cause failure of the structure and design and lead to potential hazards”

Scope and Purpose of I-35W Bridge

Minneapolis is the largest city of Minnesota. This bridge connected the Minneapolis neighborhoods of Down East and Marcy-Holmes. The bridge served as the boundary of Southeast of the “Mississippi Mile”. This Bridge was designed in 1961 by Sverdrup and Parcel, AASHO (American Association of State Highway Officials and now specification standards of now American Association of State Highway and Transportation Officials). The total costs for this project were US$5.2 million. Steel Trusses and Deck were built by Hurcon Inc. and Industrial Construction Company. The construction began in 1964, and the bridge was opened to traffic in 1967.

Fault of Design

On 19th December, 1985, the temperature was -30 degree Fahrenheit (-34 degree centigrade). Cars were experiencing the problem of black ice, and there was an enormous amount of ice on the bridge. It was found that bridge was the most cold weather spot in Twin Cities Freeway System. This is the reason because of the thin layer of black ice formed there. In January 1999, the work started with magnesium chloride solutions in order to remove black ice effects on winter. In October 1999, there was a system installed on the bridge to spray potassium acetate solution, to keep the area clean from black ice. It is expected that potassium acetate may be the cause of bridge collapse. Bridge was monitored annually by Mn/DOT, but there was no inspection report on 2007. This was due to the construction work. There were several reports against the bridge structure after the collapse. In 1990, Federal government declared I-35 W Bridge as structurally deficient (Safety Board2008, November).. This was due to the fact that much corrosion found in its bearing. According to the Study of 2001, it was discovered that there was a cracking in the cross girders at the end of approach spans. The situation was notices, and it was recommended to drill the cracks and addition of supports to girders was necessary in order to avoid further propagation of distortion. The report also showed that there was a lack of ...