In the mid-nineteenth century, urban areas faced a significant architectural constraint: buildings rarely exceeded six stories. While masonry techniques could support taller structures, the primary limiting factor was the lack of a safe mechanism for vertical transport. Existing hoists, suspended by simple hemp ropes, were notoriously prone to snapping, making them far too dangerous for passenger use. Elisha Otis revolutionized this landscape in 1852 by inventing the safety elevator, which featured a spring-operated utility brake that automatically engaged if the hoisting cable broke. Otis’s innovation immediately resolved the public's deep-seated fear of falling. By guaranteeing passenger safety, this invention catalyzed a massive shift in urban design, prompting architects to design much taller buildings. Consequently, the commercial value of upper floors—previously considered undesirable due to the strenuous climb—skyrocketed, paving the way for the modern skyscraper and transforming the density of cities worldwide.
According to the passage, Elisha Otis’s invention of the safety elevator directly caused which of the following changes in nineteenth-century cities?
- A dramatic increase in the height of buildings and the commercial value of their upper floors.Cevap
- BA sudden rise in the value of upper floors, which inspired engineers to design a safer braking system.
- CThe development of masonry techniques that could support structures taller than six stories.
- DThe widespread use of hemp ropes to operate passenger and cargo hoists.