When designing large structures such as bridges, ships, dams, and various modes of transportation, engineers must determine what methods and materials should be used in order to design, build and maintain the structure for a long period of time. A strict code of ethics must be followed in order to reduce possible harm and tragedy. Although this process is used in an attempt to minimize design errors and possible failures, unknown factors such as population increase, natural disasters, and lack of manpower can cause the design to fail. structure. This is the case for the I-35W bridge over the Mississippi River and the Mianus River bridge. The Mianus River Bridge failure occurred on June 28, 1983. About one hundred feet of the northbound bridge collapsed into the Mianus River, causing three deaths. The bridge itself was built in 1958 as part of I-95, a highway connecting Florida and Maine. It was designed in the pins and hangers style which was mainly used in the 1950s in order to reduce the cost of construction. The bridge is located in Greenwich, Connecticut and was comprised of three lanes traveling in each direction and was supposed to be monitored and maintained by the Connecticut Department of Transportation. At some point during the use of the bridge, it was decided to cover the drainage holes in the bridge, which prevented any accumulation of water. This decision, coupled with the fact that the bridge was considered a failure critical bridge, caused it to fail. As the water was not directed to a drainage source, it would settle in the cracks and foundations, which would later affect the axles of the bridge. Once the lower pin failed in the bridge, too much stress was placed on the upper pins...... middle of paper ...... once the bridge was completed. Because the pin-and-hanger style bridge was often considered a failure-critical bridge, it is no longer used in new bridge construction in the United States since the collapse of the Mianus River Bridge. Many have decided to equip pin and hanger type bridges with a type of safety net called a "catcher's glove", which is a beam placed under the beam in order to catch it in the event of a bridge failure. Additionally, modernization of the bridge with larger gussets was considered. Regarding the I-35 Minnesota Bridge, if the water discharge points were left open, the bridge would not have collected water and caused corrosion of the axles and possible failure of the bridge. By preparing for any natural events that the bridge might interact with while in use during the design process, further failures could also be avoided..