Highway Overcrossings Research Articles

The Santa Barbara earthquake of 13 august, 1978

AbstractAlthough the Santa Barbara earthquake was only a moderate seismic event, it was the most destructive earthquake in the United States in 1978 causing more than $7 million damage and at least 65 injuries. Reported Richter magnitudes ranged from 5–1 to 5–7, but estimates based on strong motion records yielded about 5–8. Due to the geologic features of the earthquake, the intensity of strong shaking was geographically asymmetrical, being much larger in the Goleta area north and west of the epicentre. Peak ground accelerations of 0–40 g were recorded near Goleta, while 0–23 g was recorded closer to the epicentre in Santa Barbara. The duration of strongest shaking was only about 2–3 s. The earthquake caused light cracking of shear walls in multi‐storey reinforced concrete structures, as well as damage to highway overcrossings, many mobile homes and to rooftop mechanical equipment. Presented in this paper are the results of preliminary investigations of the engineering features of this earthquake.

Laboratory Model Testing for Earthquake Loading

Two types of facilities used at the University of California, Berkeley, for laboratory syudy of earthquake response characteristics of typical structures are described: (1)A 20-ft square shaking table; and (2)a variety of controlled loading devices. Shaking table tests of a 0.7 scale concrete building frame, a 1/30 scale highway overcrossing, and a 1/3 scale liquid storage tanks are mentioned. Controlled loading facility testing of concrete and steel members, joints, and subassemblages is described and typical results presented to demonstrate typical behavior mechanisms. Note that loading rate has only a minor influence on the behavior of concrete specimens, so earthquake response behavior can be evaluated by pseudo-static testing procedures. Other comparative advantages and disadvantages of the two types of testing facilities are presented.