Construction and Obstacles 1 2 3

Back in the 1850's, people who wanted to build skyscrapers or taller buildings had a huge obstacle. They did not know of one great metal, steel. They only knew how to build buildings with stone or bricks. As a result, they could only build buildings no higher than four or five floors, because if they had wanted build any taller, the lower walls would be so thick in order to support the floors above that there would not be much space left for the rooms or offices! People needed a firm yet thin frame of columns and beams to support the floors above. The big discovery of steel came in the 1860's. Steel was strong and firm, and lighter than stones and bricks. It was the perfect material for building strong, thin skyscraper frames. In the early 20th century, concrete frames, sometimes with steel in it, were used to build skyscrapers.

However, as soon a skyscraper using steel was built, a big problem came up. No one wanted to walk ten or more flights steps up to their home or offices! Wasn't there a better way to transport people? Of course there was! In the 1850's a safety elevator, powered by steam, was invented by Elisha Otis, and in the 1880's electric elevators were invented. (For more information on elevators, refer to Function: elevators) Nowadays, when people want to build a skyscraper, they ask a design architect to design the shape and the style of the skyscraper. After the design architect(s) have decided on these issues, a structural engineer takes over. He or she must design the skyscraper in the shape and style wanted, but also must make sure the structure can support the weight of all the people and furniture on the floors, called the live loads, and also the weight of the building itself, the dead loads. Continue