The Second Industrial Revolution, which can be dated from 1870 to 1914, affected the fabric of American society in a number of ways.
First, it helped to create a truly transcontinental America, one that no longer had a frontier. The revolution allowed a railroad boom that brought people all across America and led Frederick Jackson Turner to declare that the West was closed. This meant that the US was no longer a frontier society with empty land to push into.
Second, it helped to create demand for massive waves of immigrants to work in the factories of the East. This changed American society by making it more diverse. It forced America to figure out how to deal with masses of poor workers in the cities and how to assimilate large numbers of immigrants from countries that had not previously sent immigrants to the US.
Finally, the revolution created a consumer society in the US. This revolution was based more on consumer goods than on massive industrial machinery. This meant that it created things that people used to make their lives easier and more fun. Evidence of this change was seen as early as the 1920s, when American society became more focused on leisure and on consumerism.
These were three of the most important ways in which the Second Industrial Revolution impacted the fabric of American society.