Answer:
Three ways that real-life earthquake conditions may differ from those made by a shaking table are:
Duration: Real-life earthquakes can last for several minutes or even hours, while shaking table tests are typically limited to a few seconds or minutes. The longer duration of real-life earthquakes can result in more widespread damage and greater impacts on structures.
Frequency content: Real-life earthquakes can have complex frequency content, with energy distributed across a wide range of frequencies. Shaking table tests, on the other hand, typically focus on reproducing specific frequency components or waveforms. This can make it difficult to accurately replicate the full range of ground motions that can occur during a real earthquake.
Spatial variability: Real-life earthquakes can have significant spatial variability, with different parts of the ground experiencing different levels of shaking. Shaking table tests, however, typically apply uniform shaking to the entire structure or model. This can make it challenging to accurately replicate the localized damage that can occur during a real earthquake.