Notlarımı karıştırırken, Earthquake Geotechnical Engineering (Deprem Mühendisliği diyebiliriz) dersi kapsamında yaptığımız sunumun notlarını buldum
yavaştan onları paylaşaym, ilerde dersi alacak olan arkadaşların işine yarayabilir.. Notlar İngilizce olduğu için şaşırmayın baştan söyleyeyim..
Modal Tests
The model tests can be divided into two categories, namely,those performed under gravitational field of earth (generally called shaking table tests) and those performed under higher gravitational field (centrifuge tests).
Both shaking table and centrifuge model tests have certain advantages and limitations. Shaking table tests have the advantage of well controlled large amplitude, multi-axis input motions and easier experimental measurements and their use is justified if the purpose of the test is to validate the numerical model or to understand the basic failure mechanisms.
Shaking Table Test
Shaking table research has provided valuable insight into liquefaction, post-earthquake settlement, foundation response and lateral earth pressure problems. For the models used in shaking tables, soil can be placed, compacted and instrumented relatively easily. Though higher gravitational stresses cannot be produced in a shaking table test, the contractive behaviour associated with high normal stresses at significant depths can be simulated by placing soil very loosely during model preparations.
In order to reproduce actual earthquake data, a six degree of freedom shaking table is essential. It is a very complex electro-hydraulic system which is very expensive and requires high maintenance and operational costs. However, when the response and failure mechanisms of earth structures like embankment, retaining wall, quay wall are of importance, single horizontal translational degree of freedom shaking tables are sufficient. The cost of actuators for shaking table exponentially increases as the payload increases. Considering these factors, a manual shaking table was designed and fabricated which can be seen below.

Centrifuge Test
A geotechnical centrifuge is used to accurately conduct model tests in studying geotechnical problems such as strength, stiffness and capacity of foundations for bridges and buildings. It makes use of centrifugal acceleration to match soil stresses in a 1/50 scale model. So, for a model container 1 m deep filled with soil, subjected to a centrifugal acceleration of 50 g, the pressures and stresses will be increased by that factor of 50.
The purpose of this centrifuge modeling and testing is to discuss the problem and results of liquefaction on building soil. Recent earthquakes have accurately provided indication on the damaging effects of liquefaction on the built environment. The series of centrifuge tests involving buildings placed on top of a uniformly layered soil deposit have been performed to determine the dominant mechanisms involved with liquefaction induced buildings.
In conclusion, the basic concept of this testing technique is to create a scale model similar in every respect to a prototype and to subject the model to an acceleration such that the increase in self-weight stresses is equivalent to those at corresponding points in the prototype. With this method, the investigator can observe, in a short period of time, a sequence of events that is analogous to that occurring in the prototype over a long period of time.