Discussion about Silver Bridge Collapse 1967 - Coursework Example

Discussion about Silver Bridge Collapse 1967 Name Institution 1. Introduction In mid-December 1967, the Silver Bridge collapsed a midst a busy traffic in that saw the death of 46 people with 31 vehicles out of the 37 in the bridge collapsing (LeRose, 2001). This incident would remain in the memories of many Americans since it happened at around 5pm when the traffic is always busy in the bridge and that it occurred at a Christmas Eve. Later investigations revealed that the wreckage could have been caused by an eyebar default in the suspension chain (Lonaker, 2006). This was as a result of a minor defect, of about 0.1 inch. Overloading and poor maintenance were thus pointed out as the cause of this collapse. The Bridge connected Knauga Ohio to Point Pleasant in through the Ohio River (Harrison, 2013). Pleasant Point directed traffics into the streets where traffic had to make a right turn at the end of the bridge to stay on route 35 causing stress and overloading but a traffic light at the street intersection also lead to traffic backup leading to more weight stress on the bridge (NIST, 2009). This paper therefore, brings new insights on the causes of the bridge collapse and how it could have been avoided. 2.0 Discussion There were various reasons and causes that both the general public and the engineering community used to describe the Silver Bridge collapse. 2.1 The sharp right turn and traffic light at the Point Pleasant Immediately after finishing the bridge, the traffic was always forced to make a fast and sharp turn to the right in order to stay on the Route 35 (Lonaker, 2006). This sharp turn would later exert more pressure on the end of the bridge by exerting weight on it. Therefore, this pressure led to uneven distribution of weight between left and right side of the bridge would make the bridge sway and vibrate unnecessarily. On the other hand, there was a large traffic light of tower at the Point Pleasant end for controlling the traffic. This would lead to occasional traffic backup on this side of the bridge thus exerting even more pressure on the bridge. From a general point of view, these two factors were rather faulted for the collapse of Silver Bridge. Thus when the new Silver Bridge was built, the traffic lights and the tool booth were removed confirming that they could have played part in the bridge’s collapse. 2.2 The failure of eyerbar chain suspension The bridge was a round 2235 feet long with its support from two chains that were made of steel eyerbars which were then connected to steel pins of 11 inch length (LeRose, 2001). It was therefore wrong for the construction group to use chains as the supporting materials of this large bridge. Chains can as well be as weak as their linking positions. These weakest links can thus cut loose when there is too much pressure exerting on them. This would later describe the weakness of any suspension bridge. What could have happened in this case is that the eye-bar that was heated treated and broke putting pressure on other bridge components or parts. In this case, the remaining steel frames usually buckle and fall down due to the new concentrated stress as was witnessed in the Silver Bridge. Besides, the failure of eyebar chain suspension could have been anticipated. This bridge was constructed in the year 1928, when the vehicles and traffics were much lighter (West Virginia State Agency Directory, 2014). However, 40 years later could have not been the same since America was witnessing increased number of vehicles with heavy traffics. Therefore, the eyerbar suspension could not support the increased weight stress on the Bridge. The bridge was never designed to carry too much weight. 2.3 lack of inspection and maintenance Investigations revealed a tiny crack on the steel which could have occurred during its manufacture (Federal Highway Administration, 2005). This was after a post –mortem that was carried out on the debris of the bridge. Therefore, there was a mishap on the eye-eye bar which would later act as the basis of its malfunctioning. When has a small crack and it is used on areas of heavy impacts like road bridges, the crack widens as the years go by which may lead to the breakage of the metal. However, there should have been a regular check up on the bridge to detect any defects on the construction materials (FHWA, 2011). This crack later became the weakest point of the chain causing a great collapse. A report from the Federal Highway Administration revealed how there had not been a clear and systematic inspection on the bridge for monitoring the bridge’s existing conditions. Since the bridges serve a large population, there ought to be measures put to ensure regular monitoring and assessment of the conditions so as to anticipate any failure. There should be a National Bridge Inspection Program (NBIP) like the one America has today which was not present at that time (Thomason, 2013). The federal government for sure must allocate funds for maintenance of main bridges since it is the same who paid their taxes that perished in such fatal Bridge collapse. Bridges must be inspected at a 24-hour basis and if a bridge has structural deficiencies, its permitted load must be reduced until repair and closure becomes an option when the bridge is unsafe (Amedudzi & McNeil, 2008). 2.4 failure of the anchorage design/poor anchorage Since the structure had a unique design, it ought to have had an innovative anchorage design. For a tall bridge, it must have been built in a strong ground that could support the heavy weights. For instance, the bedrock which anchored Silver Bridge was at a considerate depth making ordinary gravity anchorage quite impractical (Manning, 2014). Tall bridges must have a strong trough made of concrete and should be tall enough relative to the length and of the bridge. Engineering constructions at Silver Bridge put little effort on the anchorage design thus they built unusual support that would lead to the easy collapse of the bridge. 2.5 Corrosion cracking from stress Corrosion cracking occurs due to stresses and form brittle cracks in normal sound materials through simultaneous and frequent tensile stresses and corrosive environments. Therefore Silver Bridge faced corrosion stress due to corrosion fatigue that combined with cyclic stresses making the disaster inevitable in such a corrosive surrounding or environment. These corrosion factors had a weakening effect entire structure by primarily affecting the whole eye-bar. 3.0 Conclusion The collapse of Silver Bridge in 1967 brought new insights into bridge constructions. People lost their lives and the federal government had to probe the cause of this fateful event. Firstly, the sharp right turn as well as a traffic light at the right side of the bridge or Point Pleasant made the backup vehicles to exert pressure on this side of this bridge. This would prompt the removal of this traffic light. Secondly, the chain suspension has been determined as the structural failure that led to collapse of the bridge. The eye bar gave in to increased weight from the vehicles and it finally broke apart. This bridge was built in 19828 when vehicles were lighter with little traffic but it could not support the heavier traffic forty years later. In addition, there was no maintenance on the bridge since post-mortem examination revealed a crack on the steel bar which may have occurred during manufacturing of the eye-bar. On the other hand, it is also imperative to fault anchorage design that could not support the whole structure. Finally, corrosion cracking that result from excess stressful and corrosive environment continually weakened the bridge to its collapse. References Amedudzi, A. A & McNeil, S. (2008). Infrastructure Reporting and Asset Management: Best Practices and Opportunities. New York City: Virginia. Federal Highway Administration, (2005). Silver Bridge Collapse. Retrieved from http://35wbridge.pbworks.com/w/page/900751/Silver%20Bridge%20Collapse FHWA, (2011). Public Roads: Bridge Research leading the way to the future. https://www.fhwa.dot.gov/publications/publicroads/95summer/p95su23.cfm Harrison, H. (October 2013). Dec. 15, 1967-Silver Bridge Collapse in Point Pleasant Kills 46(Part 1). Retrieved from www.wchstv.com/newsroom/rememberwhen/rem131006_28.shtml LeRose, C. (October 2001). The collapse of the Silver Bridge, West Virginia Historical Society Quarterly, 15(4). Lonaker, T. (2006). Silver Bridge Collapse: The Long Day, retrieved from Manning, J.R. (2014). Historic and Notable Bridges Of USA: The Collapse of The Silver bridge bridgehunt.com. Retrieved from http://bridgehunter.com/oh/gallia/silver/ NIST, (2009). The collapse of the Silver Bridge: NBS Determines Cause. Retrieved fromhttp://museum.nist.gov/exhibits/silverbridge/ Thomason, R. (2013). US Code - Section 151: National bridge inspection program. Retrieved from http://codes.lp.findlaw.com/uscode/23/1/151 West Virginia State Agency Directory, (2014). Silver Bridge. Retrieved from http://www.transportation.wv.gov/highways/bridge_facts/Modern-Bridges/Pages/Silver.aspx Read More