During my summer internship, I noticed how one or two pages are dedicated to information about the structure of beams, columns, and walls. I noticed that every detail was specified to an exact measurement, and wondered how engineers decided what dimensions, materials, etc. each element needs to be. After doing some research, I figured out that the first things I needed to know were building loads.

Buildings loads are the forces that buildings must sustain throughout their lifetime. Engineers categorize them separately under dead loads, live loads, and environmental loads. Dead loads are forces that are permanently exerted on the building. This mainly concerns the weight of the building itself and how its materials, like concrete or steel, contribute to that. Live loads are temporary forces created using the building. People walking, furniture being placed, and vehicles are some examples of live loads that engineers need to account for in the structure of the building. Finally, environmental loads are forces from nature such as wind, rain, and snow as well as occasional natural disasters like earthquakes and floods. Engineers create a code that takes into account all of these forces working together and then design structural elements of the building to prevent these forces from causing damage.

For example, buildings in the Bay Area are constantly under threat from potential earthquakes. Engineers needed to account for this threat by introducing structural elements to keep the forces in check. They consider the symmetry of buildings when designing earthquake safe structures. Structures that cause uneven weight distribution make the building susceptible to breaking when under the stress of an earthquake, while symmetrical design helps keep forces spread evenly resulting in a lower likelihood of cracks and breaks in the building. Another element of buildings that make them resistant to earthquakes is using lightweight material. Walls and roofs made of lightweight material are less likely to collapse under stress from earthquakes, making them a preferred choice in the bay area. 

Engineers need to account for these forces that structures face every day more than just making the building strong. Every design choice made in the structural supports like columns and beams help to keep buildings safer from forces that everyday people may not notice.

Above is a video that details methods that engineers use to make buildings earthquake proof: