Located on one of the most active seismic regions in the world, Taiwan suffers from frequent earthquakes caused by the Circum Pacific Seismic Belt. In fact, about twenty significantly strong earthquakes have been recorded in the history of Taiwan. To compensate for this, earthquake hazard needs to be taken into account in all civil engineering constructions to ensure sufficient resistance against the shakes. The National Center for Research on Earthquake Engineering (NCREE) was established in 1990. Since then, this institution has worked endlessly to upgrade seismic resistant design standards for all constructions and provides feedback to the engineering community through research and development.
It is hoped that through the coordinated activities of NCREE, the enthusiasm to conduct high-quality research will be stimulated to bring out the full potential of its participants. These activities will include the holding of seminars and workshops on a regular basis in which knowledge can be advanced and continually improved. In addition, special emphasis has been and will continually be given to technology transfer to the engineering professions for enhanced seismic-resistant designs.
Today, research in earthquake engineering has entered a new level of interactive examinations between theory and experiment based on pure theory. Secondly, seismic resistant design standards have been established to make research results applicable in the engineering community. NCREE uses the prototype of on-site experimental workstations along with integrated research projects, along with the large simulation laboratory to perform related earthquake resistant tests. It is the goal of the National Center for Research on Earthquake Engineering to achieve breakthroughs on future research in the earthquake-engineering field.
Tri-axial Seismic Shaking Table:
The seismic simulator in the NCREE possesses 6 degrees of freedom to simulate earthquake motion in 3 axes. Major earthquakes occurred in the world can be reproduced by the seismic simulator in the NCREE.The size of the shaking table of the seismic simulator is 5m X 5M and its mass is 27tons. Structural model with maximum payload 50 tons can be accommodated on the table. The shaking table is a box shaped structure so that high bending and torsional stiffness can be achieved with limited mass of the table.
The shaking table is driven by 12 hydraulic actuators 4 actuators for each axis. The hydraulic power is provided by 2 electrical pumps and 3 diesel pumps which offer a total flow rate of 1,235 gpm with a working pressure of 210kg/cm2, The weight of the shaking table and the structural model is balanced by 4 static supports.
The reaction forces of the actuators are provided by the reaction mass which is 16m (length) X 16(width) X 7.6m(height in dimension and about 4,000 tons in mass. In order to further improve the quality of the testing environment, the reaction mass is isolated from the fixed foundation by 96 air springs and 80 dampers.
Reaction Wall & Strong Floor Testing System:
The reaction wall and strong floor provide the need for large-scale structural and earthquake engineering experimental facilities. This intergraded facility has the capability to perform large or full scale seismic tests by using various experimental methods, such as traditional quasi-static tests, cyclic loading tests and pseudodynamic tests.
The L-shaped reaction wall in this center adopts the cell type design with stepwise arrangement of wall heights including 15m, 12m, 9m and 6m and the respective wall width of 15.5m, 15.5m, 12m and 12m.The reaction wall consists of two 1.2m thick reinforced and post-tensioned concrete plates, which are parallel at a distance of 2.6m, and was enhanced with a 0.4m thick reinforces concrete plate in between at an interval of 3m. The strong floor was designed as a reinforced concrete slab which has a size of 60 x1.2m thick. The specified compressive strength of the concrete for both the reaction wall and strong floor is 350 kg/cm2.
There are 18sets of static hydraulic actuators and 6 sets of dynamic hydraulic actuators in this laboratory. Their detailed characteristics are listed in the table. Five hydraulic hard-line ports are appropriately located in the reaction wall and strong floor. These ports provide for a total of 1325 gpm hydraulic power supply and return as a drain line. The working pressure for the hydraulic system is 210 kg/cm2.