The fatalities and injuries are our major overall concern. This is the starting point of the incident. And the cost to replace the bridge was $234 million, for a grand total of almost half a billion dollars. AEM provided the cause of collapse of the I35-W Bridge. The increase in dead load was a result of two previous repairs. The second bridge was substantially heavier than the first. factors, and estimate the time-to-failure of a bridge through FTA. At Quebec, the greatest bridge in the world was under construction in 1907 under severe financial constraints, with inadequate funds provided for either engineering work or the bridge itself. The lives of those injured and killed in this incident are the top priority in this situation, so we start with our safety goal and work directly backwards to injuries and fatalities. The reason gusset plates are not considered important to the load rating is that there is a general assumption that gusset plates (the key joints on the bridge) are stronger than the parts they connect. The Royal Commission Report, which investigated the collapse and identified the engineering and procedural errors that had lead to it, remains a pioneering document in the field of forensic engineering. In the rush following the final financial arrangements of 1903, the necessity of revising the assumed weights was overlooked both by the engineers of the Phoenix Bridge Company and by those of the Quebec Bridge Company, with the result that the bridge members would have been considerably over-stressed after completion. This hypothesis clarified why the low-speed wind 68 km/h caused the tremendous oscillatory motions and decimation of the Tacoma Narrows Bridge. A highest oscillation amplitude of 1 m was observed. It was at time of construction the longest cantilever bridge in the world with clear span of 1800 ft. His health was poor and because of this, he never visited the site once construction began on the superstructure. He eventually became vice president of the company. Lost your password? On 30 October 2022, a pedestrian suspension bridge over the Machchhu River in the city of Morbi in Gujarat, India, collapsed, causing the deaths of at least 135 people and injuries to more than 180 others. Remember, gusset plates are joints that support other parts. The toppling or failure of the pier three was the initiation of the collapse which resulted in the collapse of span three and four. The entire south half of the bridge, approximately 189 MN (19,000 tons) of steel, fell into the waters of the St. Lawrence within 15 seconds. These constraints had delayed engineering analysis and led to adoption of unconservative specifications. He allowed 145 MPa (21 ksi) for normal loading and 165 MPa (24 ksi) under extreme loading conditions. The bridge collapsed during evening rush hour, and there was roadwork underway on the bridge. A recent review of the history of the bridge and the two collapses was written by Middleton (2001). 56, Sept. 14, pg. The reaction that takes place when the sulphates in the marine waters enter the concrete, the abrasive effect created by the sulphates in sea water is not as severe as the effect of sulphates in the ground and underground waters. This engineer would, in a sense, be double-checking Coopers work and ultimately have the final authority. Depending on what level of detail you need to be able to solve your problem, you have the option of demonstrating as few or as many causes as necessary by using a Cause Map to perform root cause analysis rather than listing causes or attempting to pinpoint a root cause and stopping at that. The following points describe the findings of the PWA report: The PWA finally inferred that the Tacoma Narrows Bridge failed due to its extraordinary flexibility, lightness, and narrowness. Early on in the investigation several possibilities that could have caused the fracture of the gusset plate were considered, and later refuted. Over time, some of the member deflections increased. Engineers and others in charge must be open minded to the ideas of the laborers, many of which have years of hands on experience. This process continues as we build our Cause Map. More importantly, it was the only one of the three that was fatal. The lessons learned from the case had many important impacts on the engineering profession, particularly in Canada and the U.S. Support for this research was provided by the National Science Foundation under the project Developing Case Studies in Failures and Ethics for Engineering Educators, project number DUE 0127419. Tennessee State Route 69 Bridge Collapse Case Study Introduction & Overview. The top chords for the anchor and cantilever arms in the Quebec Bridge were slightly curved, for aesthetic reasons. It was repaired and placed into the structure. In his haste to get to his destination, he neglected to send the information. I have evolved another theory, which is a possible if not the probable one. The National Transportation Safety Board (NTSB) conducted a thorough investigation after the incident. American Society of Civil Engineers, New York, New York. The process of designing, building and inspecting the bridge had plenty of assumptions. These measures could have reduced the lift and oscillation. Solution #13: Add Specific Training on Gusset Plate Inspections Middleton, William D. (2001). Because there was insufficient design thickness of the gusset plate, as is evidenced by its inch thickness rather than the standard 1 inch. Firstly, the sidewalks and curbs of the bridge started to collapse with the crumbling of street-lights. However, better design and engineering have clearly not eliminated the risk of the bridge collapse. That way, we can continue to consider this impact while we (or other researchers) continue to gather research about this impact. At the time this error was discovered, a large portion of the fabrication had been completed and a considerable amount of bridge erection was finished. The Public Works Administration (PWA) created a board of engineers to investigate the incident. It was ignored in the absence of the chief engineer. TWO. The presence of sulphates in the cement matrix can cause a chemical reaction. After another routine inspection, chord A9L was placed under observation when its initial deflection of 19 mm () had increased to 57 mm (2 ) in less than two weeks. These chords have been hit by those suspended beams used during the erection, while they were being put in place or taken down. However, the rigidity against static and dynamic loads couldn't be found using the same method. That helps us, because we now have a better understanding of the situation as well as more room for solutions. With a site selected, bridge design proposals poured in (p. 26, Middleton, 2001). After the collapse, the government took over the design and construction of the new bridge. These were questioned by the bridge engineer for the Railways and Canals as being unusually high. BM Bridge Masters Common reasons for bridge failures, Christopher J. However, the project did not gather momentum until 1887, when a group of businessmen and political leaders came together and formed the Quebec Bridge Committee. Download Product Flyer is to download PDF in new tab. Joachim Scheer, Linda Wilharm (Translator) ISBN: 978-3-433-02951- May 2010 321 Pages . However, it also suffered a partial collapse when the middle span fell into the river. Download Product Flyer is to download PDF in new tab. The last piece of information we want to record is the frequency of the incident. (1907a). He replaced the stiffening trusses with plate girders of lesser weight that left the Tacoma Narrows Bridge with only 35% of the stiffness of the Golden Gate Bridge. To clarify, this is a photo of a gusset plate: Interstate 35W Bridge Main Truss Node (National Transportation Safety Board photo). Engineering Record (ER). Unfortunately, that solution became a cause in our Cause Map of the more recent bridge collapse. They relayed a message back by telephone, saying that it was safe to resume work on the bridge. Engineering Record (ER). Sometimes, when looking at a past incident, a lack of evidence may leave things uncertain. The increase in volume due to the swelling leads to cracks in the concrete. But when they are not properly sized, this may not happen. What must be the maximum dry density of Granular Sub Base & Wet Mix Macadam used What is the Safe Bearing Capacity values for Different Soils? Bridges are one of the most important structures of transportation networks. Download Product Flyer is to download PDF in new tab. It was assumed that the final authority rested with Theodore Cooper. During construction, the two erected spans of the steel superstructure suddenly collapsed and fell into the Tennessee River. Of the three ironworkers working on the steel . Another advancement was the formation of two organizations, the American Institute for Steel Construction in 1921, and the American Association of State Highway and Transportation Officials in 1914. Finished Papers. The new units stresses were accepted anyway based solely on Coopers reputation (Holgate, et al., 1908). The Safety Goal is where we will start. The designer of the Tacoma Narrows Bridge wanted the bridge to have a sleek appearance, that is why the stiffening truss girder was not adopted. Collapse of the Point Pleasant Bridge On a cold winter evening, the bridge suddenly collapsed due to the failure of the connection between the eyebar to the first joint on the north side of the bridge. You will receive a link and will create a new password via email. The winds reached speeds of 40-45 . Which is the code used for the design of the RCC Bridge? The completed piers would stand approximately 8 m (26.5 ft.) above the highest water level. Fortunately, security cameras and traffic monitoring allow us to pinpoint the exact time when the bridge began to fall: 6:05 p.m. on August 1, 2007. Worked for Phoenix Bridge Company, Chief Engineer for Phoenix Bridge Company, Bridge Inspector, Civil Engineering Graduate from Princeton, hired by Cooper, Chief Designing Engineer for Phoenix Bridge Company, Commissioned to review design work on the bridge after the collapse, The collapse of the Quebec Bridge resulted from the failure of the lower chords in the anchor arm near the main pier. The 19th-century bridge had reopened five days earlier, in time for Diwali and the Gujarati New Year . His method of accounting for railroad loads on bridge structures became widely used (p. 37, Middleton, 2001). The bridge designer, Leon Moisseiff, wanted to give the bridge a sleek appearance without utilizing stiffening trusses. These characteristics helped the wind force, which occurred on the failure day, to cause the torsional motions that led to the collapse of the bridge. The Anchor Pier Towers of the Quebec Bridge (1907), Engineering Record, Vol. The immediate cause of failure was found to be the buckling of compression chords A9L and A9R. These butt splices were bolted to allow for movement. Cooper insisted on retaining full control of the project, even at a considerable distance. The full Cause Map based on the information found in the NTSB report has more than 50 causes, but even more detail can be added for clarification or if additional information arises as part of the investigation. The deaths and injuries took place because the main span of the bridge collapsed. However, Norman McLure wrote, One thing I am reasonably sure of, and that is that the bend has occurred since the chord has been under stress, and was not present when the chords were placed. While this dispute of how the bend occurred in chords, 7L and 8L was going on, McLure reported to Cooper another occurrence of a similar bend in chords 8L and 9L (pp. These hold-down ties were proposed as temporary measures, and one of the holding ties broke seven days after installation. Copyright 2000-document.write(new Date().getFullYear()) by John Wiley & Sons, Inc., or related companies. Each bridge span was 30 m (100 ft) long, three travel lanes wide, with a 53 skew. The bridge collapsed during construction on August 29, 1907, killing eighty-six workers. The mass of the hogging side spans dragged the towers 4 m toward the shore, and the crumbling bridge, at last, came to rest. No clear chain of command existed. Gusset plates are not generally considered essential to the load rating and they were excluded to simplify overall analysis. Another source of sulphate is the recycled concrete used as aggregate. The failure of the West Gate Project was a result of poor project management procedures at all levels of the project. The message from Cooper reached the Phoenixville office at 1:15 p.m. Wear effect: If concrete surfaces are subjected to friction effect, they lose mass after a long time. At around 3:00 p.m. Phoenixvilles chief engineer returned to his office. 55, January 26, pgs. Quebec Bridge 25-Jan-19 Majzoob Mohammed Arbab 1. The construction was started in April 1977 and finished in October 1979. Nowadays, concrete production with long durability has started to gain importance besides focusing on high strength. Cause Mapping any incident requires first asking four questions: If you were facilitating a Cause Mapping session all of those who might have knowledge of the I-35 Bridge collapse an asked for the reason it fell, you would hear: It was the initial structure of the bridge., Yes, but if periodic inspections had included the proper steps, the collapse could have been bypassed. Dawson printer to the King Ottawa. 321Pages. A cantilever bridge was proposed as the most feasible design to bridge the harsh, icy waters of the St. Lawrence River. Numerous researchers accepted that this clarification disregards the significant inquiry concerning how wind, arbitrary in nature, could produce a periodic impulse. Cooper met with Schreiber personally. Royal Commission Quebec Bridge Inquiry Report. McLure continued to argue that the bends in the members had occurred after they were installed. Two months later the company awarded contracts to the Phoenix Bridge Company for construction of the superstructure and to the Davis Firm for construction of the substructure. However, this positive feature may disappear as a result of a chemical process called carbonation. Univ. The bridge was designed for static and dynamic loads using the same method. In an ideal column each part would take its share of the load and no connection would be required. There had already been a three-day strike over working conditions, and the workers who had not agreed with the new terms had left. McLure will be over at five oclock. Coopers reasoning for informing the Phoenixville office rather than directly relaying it to the site, was that he felt that action would be taken faster if the information went to the site through Phoenixville. Unfortunately, because of a few centimeters thickness of shell layer reinforce steel begin to rust. This is where debate between decision makers becomes constructive. A cantilever bridge was proposed as the most feasible design to bridge the harsh, icy waters of the St. Lawrence River. The top 5.8 m (19 ft.) of each pier was made of solid granite. All rights reserved. The PWA's hypothesis, in any case, isn't the only clarification. 4.7/5. Examine if you cannot find evidence of the blow, and make inquiries of the men in charge. McLure did as he was instructed, and reported back to Cooper that there was no evidence of such an incident (p. 74, Middleton, 2001). As for the error going unnoticed, the State of Minnesota may be able to find really solid solutions in this part of the Cause Map. The basic configuration of a cantilever bridge is shown in figure 1. This paper describes the failure and its causes and suggests engineering lessons to be learned. For example, to break a window requires both something to strike it and the glass to be fragile enough to break. This story is a few younger male who case study analysis tacoma narrows bridge failure is Blessed to satisfy a girl of his goals. Solution #10: Educate on the Importance of Gusset Plates These were not listed, contributing to an eventual incomplete review process. Cooper, although the most experienced, seemed to be the most confused by the problem. Presented By Things Simplified ( A New Perspective ) 2. The second attempt to bridge the St. Lawrence was not without problems. Bridge Failure Cases. Deflections were first noticed as early as mid-June, and were reported to Cooper by his on-site inspector, Norman McLure. Comparison of Assumed and Actual Dead Load. Otherwise, the company would pay $5,000 per month after this deadline to the Quebec Bridge Company until the project was finished (Holgate et al., 1908, Middleton, 2001). When you join you get additional benefits. 92-94. Montreal already had the Grand Trunk railway system, which passes through it from the west connecting it to Toronto. Reading time: 1 minuteDifferent modes of failures of bridge structures under different stages of load either man-made or natural cause, is necessary to develop strong and highly sustainable structures. Freeze and thaw effect: If the concrete is exposed to frost immediately after mixing, frozen water volume increases by about 9% and it is moved toward the gaps in the concrete. But it does show that when you are building a Cause Map to perform extensive Root Cause Analysis of an incident, you may see a cause in multiple places. Root Cause Analysis Solutions for the I-35 Bridge Collapse. Subsequent inspections turned up more deflecting chords in August. Compression members had been cambered, so that under load the joints would line up and could be riveted together. Erection of the superstructure portion of the bridge did not begin until July 22, 1905. A contributing variable may have been slippage of a band that held the cables. Engineering Record (ER). University at Buffalo School of Engineering and Applied Sciences (, COVID-19 Discipline-Specific Online Teaching Resources, Peer Review & Editorial Office Management, The Editor's Role: Development & Innovation, People In Research: Interviews & Inspiration, General & Introductory Civil Engineering & Construction. Updated: 01 Nov 2022, 05:58 AM IST PTI. Since the Cause Map is created from the perspective of the State of Minnesota as the principal organization, we have filled out our outline from the States perspective.
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