Seismic base isolation of a building by using natural materials - shake table testing and numerical modeling


Seizmička izolacija osnove građevine
s uporabom prirodnih materijala -
testiranje s potresnom platformom
i numeričko modeliranje

This project was funded by the Croatian Science Foundation under the number IP-06-2016-5325.
Research team members are grateful for support.

Project summary

The primary objective of the project is creation and experimental verification of an innovative concept for reducing seismic forces acting on low and middle high buildings by using aseismic layer made of natural materials below foundation. Two solutions of such layer are planned. The intention is to make an efficient, rational and easy-to-implement concept, with its wide practical application. First, the effectiveness of the planned aseismic layers would be experimentally tested on the model of a rigid building, by varying several their technical - technological parameters, in order to transfer seismic acceleration (force) on the building as less as possible. The first aseismic layer is predicted as consisted only of natural stone pebbles, and the other of the natural stone pebbles in combination with a thin layer of a "sliding" material.

Afterwards, the behaviour of real buildings with the above mentioned non-seismic layers would be experimentally tested under different earthquakes. Simplified reduced models of buildings that simulate their dynamic characteristics well would be used. Four one-degree models with different stiffness would be tested to simulate the behaviour of buildings with different stiffness. The same building models would be tested for the case without the aseismic layer, in order to verify the effectiveness of the predicted seismic isolation.

If the results of the study would confirm expectations, the proposed concept of seismic isolation would have the following advantages compared to conventional seismic isolation using discrete, technically complex and expensive systems: rationality, simplicity, sustainability, market expansion, eligibility for poorer countries, etc. One of the objectives of the project is the development of numerical models for reliable seismic analysis of planar structures with the planned seismic isolation, as well as the proposal of simple engineering expressions for the calculation of the shear strength capacity and deformability of the aseismic layer.

It is believed that the successful implementation of the proposed project would provide a valuable contribution to the development of science and practice in the concerned area.

Project team

  • Prof. Jure Radnić, Ph.D. (FGAG Split, Croatia)
  • Prof. Amr S. Elnashai, Ph.D. (College of Engineering, The Pennsylvania State University, USA)
  • Prof. Atilla Ansal, Ph.D. (Özyeğin University, School of Engineering, Istanbul, Turkey)
  • Prof. Domagoj Matešan, Ph.D. (FGAG Split, Croatia)
  • Assoc. prof. Nikola Grgić, Ph.D. (FGAG Split, Croatia)
  • Goran Baloević, Ph.D. (FGAG Split, Croatia)
  • Ivan Banović (FGAG Split, Croatia)

Project leader prof. Jure Radnić is a recognized expert with extensive experience in the field of design, numerical modelling and experimental testing of structures (including the area of earthquake engineering and structural dynamics), and educational (teaching) work. He is the author of the shake-table intended to perform the proposed experimental research and already has realized several similar projects. He would plan and lead the proposed research and actively participated in all stages of its implementation.

Prof. Amr S. Elnashai is a world recognized expert in the field of earthquake engineering and structural dynamics. He is the Dean of Department of Engineering at the Pennsylvania State University. He is also the founder and editor in chief of the Journal of Earthquake Engineering and a member of the British Royal Academy of Engineering. He would participate in design and creation of planned seismic isolation of a building, problem solving of model testing and dissemination of research results.

Prof. Atilla Ansal is a world recognized expert in the field of geotechnical earthquake engineering. He is a professor at the University of Ozyegin, Istanbul, and a tenured professor at many leading universities in the world. He is the President of the European Association for Earthquake Engineering and Engineering Seismology and chief editor of the Bulletin of Earthquake Engineering. He would participate in the design and creation of the proposed aseismic layers of soil, problem solving of model tests related to soil - structure problems and dissemination of research results.

Prof. Domagoj Matešan is an experienced researcher in the field of numerical modelling of behaviour of structures under static and dynamic loading. He would participate in the development of a numerical model for simulation of the behaviour of structures with seismic base isolation and dissemination of research results.

Associate Professor Nikola Grgić (thesis: Experimental investigation and numerical modelling of the behaviour of slender reinforced concrete columns in seismic conditions) and postdoctoral researcher Goran Baloević (thesis: Experimental investigation and numerical modeming of masonry-infilled concrete and steel frames under static and dynamic loading) have experience in implementation of similar research projects using the shake-table, the development of models for testing and implementation of tests (management of the shake-table), measurements and processing of measured results. They would participate in the design and implementation of aseismic layers and building models, in performing of all tests with the shake-table, in processing of test results and the in dissemination of research results.

Phd student Ivan Banović, MSc. (Expert Associate at FGAG) works on a doctoral thesis in the field of seismic isolation of buildings. It is envisaged for him to participate in all phases of the project.

Project goals

  1. The development of an efficient and widely applicable solutions for reducing seismic forces on buildings using continuous seismic isolation under their foundations, so that buildings could be more rational (cheaper) to build, more safer under an earthquake, with minimal damage of building under an earthquake (rational maintenance), and with minimal displacements under an earthquake (increasing the quality of usage, i.e. reducing the unpleasant psychological feeling of building user under an earthquake).
  2. Search for two effective aseismic layers below foundation of a building made from natural materials (innovative concept), with intention to reduce seismic forces on buildings as much as possible (for at least 15 %), so they could fulfil expectations stated in Objective 1. One aseismic layer would be made only from natural stone pebbles, and the other one from natural stone pebbles combined with other natural or some cheap material.
  3. Experimental proof using a shake-table that previously stated aseismic layers can adequately reduce seismic forces on structures.
  4. Application of at least one patent proposal for technical and technological solutions of considered aseismic layers.
  5. Incentives on further scientific research with the appliance of natural and cheaper materials for seismic base isolation of a building.
  6. Development of nonlinear numerical model for reliable seismic analysis of structures with aseismic layer of natural materials below foundation, as well as proposition of simple expressions for simplified engineering calculation of generated horizontal seismic forces and displacements of structures with the proposed seismic isolation.
  7. Issuing research results in prestigious world journals.
  8. Strengthening scientific cooperation with leading foreign scientists in the field of structural dynamics and earthquake engineering.
  9. Contribution to qualification for young scientists.