EchelonStrike2016 wrote:
During construction of the Quebec Bridge in 1907, the bridge’s designer, Theodore Cooper, received word that the suspended span being built out from the bridge’s cantilever was deflecting downward by a fraction of an inch. Before he could telegraph to freeze the project, the whole cantilever arm broke off and plunged, along with seven dozens workers, into the St. Lawrence River. It was the worst bridge construction disaster in history. As a direct result of the inquiry that followed, the engineering “rules of thumb” by which thousands of bridges had been built went down with the Quebec Bridge. Twentieth-century bridge engineers would thereafter depend on far more rigorous applications of mathematical analysis.
Which one of the following statements can be properly inferred from the passage?
(A) Bridges built before about 1907 were built without thorough mathematical analysis and, therefore, were unsafe for the public to use.
(B) Cooper’s absence from the Quebec Bridge construction site resulted in the breaking off of the cantilever.
(C) Nineteenth-century bridge engineers relied on their rules of thumb because analytical methods were inadequate to solve their design problems.
(D) Only a more rigorous application of mathematical analysis to the design of the Quebec Bridge could have prevented its collapse.
(E) Prior to 1907 the mathematical analysis incorporated in engineering rules of thumb was insufficient to completely assure the safety of bridges under construction.
The question requires us to find a logical inference from the given statements, i.e., the passage.
The passage provides the following information:
-The context is the construction of the Quebec Bridge in 1907; the bridge’s designer, Theodore Cooper, received word that the suspended span being built out from the bridge’s cantilever was deflecting downward by a fraction of an inch.
- Before he could telegraph to freeze the project, the whole cantilever arm broke off and plunged, along with seven dozens workers, into the St. Lawrence River.
- It was the worst bridge construction disaster in history. As a direct result of the inquiry that followed, the engineering “rules of thumb” by which thousands of bridges had been built went down with the Quebec Bridge.
-Twentieth-century bridge engineers would thereafter depend on far more rigorous applications of mathematical analysis.
As can be seen from the above-mentioned information, the process of measurement on which bridge construction were based played an important role and after the disaster, were changed as it was felt that the previous process was inadequate.This option mentions bridges that are already built and have been in use for a considerable amount of time. This option does not deal with the process of construction during which the measurements play an important role. So, Option A can be eliminated.All the sentences in the passage mention measurements, so the indication is that a lack of proper measurements probably had something to do with the disaster. There is no information to indicate that Cooper’s absence created the problem or that his presence could have averted the disaster. So, Option B can be eliminated.The passage only states that there were engineering “rules of thumb” by which thousands of bridges had been built; there is no mention or indication of any other method of measurement. In fact, the passage states that twentieth-century bridge engineers would thereafter depend on far more rigorous applications of mathematical analysis. So, Option C can be eliminated.This option has the adverb ‘only’, which is to be treated with caution. The passage describes an incident and mentions a result of that incident. There is no information to indicate what might have prevented the incident. The passage does state that twentieth-century bridge engineers would thereafter depend on far more rigorous applications of mathematical analysis, but that is not enough information to suggest that nothing else would have prevented the disaster. So, Option D can be eliminated.Option E states that the mathematical analysis incorporated in engineering rules of thumb prior to 1907 was insufficient to completely assure the safety of bridges under construction. This option sums up the idea that the disaster was probably caused by a gap in the process of measurement. Therefore E is the most appropriate option.Jayanthi Kumar.