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Kajima's Advanced Structural Control and Base Isolation Technologies

Seismic Structural Control System

HiDAX

  • All-Round High Performance
  • Applicable in a wide range of structures
  • Compact
  • Durable and reliable
  • HiDAX drastically reduces the vibration caused by major earthquakes and wind events.
  • From skyscrapers to low-rise buildings and civil engineering structures such as bridges. It is also cost-effective in seismic-upgrading of existing buildings.

image:Instalation Site

Installation Site

Specifications of a Standard Device

Type 2MN-type 1.5MN-type
Maximum force capacity 2.1MN 1.5MN
Maximum stroke ±60mm ±60mm
Maximum velocity 250mm/s 250mm/s
Diameter and length ø380x
1400mm
ø340x
1400mm
Weight 850kg 750kg

Line up

HiDAX-e

Latest Model

  • Simple
  • Easy to use
  • Eco-friendly

HiDAX-u

Latest Model

  • Hybrid Type
  • Simple and Sensitive

HiDAX-s

  • Speed and Sensitivity
  • All in One
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HiDAX Operating Principles

The mechanical model of the oil damper installed into the building with bracing elements is represented by a serial model involving a spring k and dashpot C.

There is an optimum damping coefficient Copy for the conventional oil damper that maximizes the energy absorption. HiDAX breaks through this conventional damper's limitation by changing C (valve opening) at a turnaround point of vibration, and provides almost twice the vibration energy absorption of the conventional devices.

In addition to the control valve, HiDAX also houses a relief valve that keeps the damper force below the permissible load to protect the device from unexpected overload.

image:Mechanical Model of Oil Damper and Brace

Mechanical Model of Oil Damper and Brace

image:Force-Velocity Relation of HiDAX

Force-Velocity Relation of HiDAX

image:Force-Displacement Relation and Behavior of HiDAX

Force-Displacement Relation and Behavior of HiDAX

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HiDAX Performance Test

Performance test on full-scale device

In various performance tests on a full-scale device, HiDAX has demonstrated theoretically expected frequency-independent performance, even for minute vibrations of ±0.1mm. It passed the 600,000-cycle durability test with ease. HiDAX showed stability and reliability when subjected to complex loadings, while the simple analytical model enabled precise simulations.

image:Performance test on full-scale device

image:The Results of HiDAX-e

The Results of HiDAX-e

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image:Comparison of Energy Absorption Capacity

Comparison of Energy Absorption Capacity

Results of seismic response analysis

This is a seismic response simulation of a 14-story building, based on a precise analytical model derived from experiments. HiDAX reduces vibration-induced deformation by approximately half compared to the state with no damper installed.

image:Seismic Response Analysis Results

Seismic Response Analysis Results

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Control Effects in Actual Building

Performance verification involving induced vibration test

A large scale vibration test was carried out an 11-story building. The upper figure shows the obtained resonance curves. Blue indicates the results when the HiDAX damping coefficient C was set to Cmin, and green shown the results when C was set to Cmax. Red is the result when HiDAX control functions normally. Compared with the lower figure which shows theoretical curves based on a simple analytical model, HiDAX reduces response to approximately half the critical level (point P) predicted for conventional oil dampers. With HiDAX, the building's damping ratio increased significantly--from 1.1% to 5.6%.

image:Chubu Electric Power Gifu Building

Chubu Electric Power Gifu Building
Use: Office
Stories: 11 floors
Structure: steel
HiDAX-s: 42 units

image:Resonance Curves of the Top Floor(Experimental Results)

Resonance Curves of the Top Floor(Experimental Results)

image:Theoretically Predicted Resonance Curves for Conventional Oil Damper Based on Simple Analytical Model

Theoretically Predicted Resonance Curves for Conventional Oil Damper Based on Simple Analytical Model

image:Test Results of Control-State-Changeover Experiment

Test Results of Control-State-Changeover Experiment
This shows the Displacement of the top floor with the excitation force kept constant. When HiDAX was changed to control-state(the power was switched on), and the vibration amplitude rapidly diminished.

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Performance assessment involving earthquake/wind observations

The Bandaijima Building in Niigata city generated important data during the 2004 Niigata Chuetsu earthquake. If the HiDAX unit had not been installed, longer duration massive sway motion about three times that actually experienced might have occurred.

Data gathered as a typhoon approached the building also suggested that many residents would have experienced significant, persistent vibrations without HiDAX. Statistical analysis of wind-induced vibration showed that the building's damping ratio rose significantly -- from about 1% to 4.2%.

image:Bandaijima Building

Bandaijima Building
Use: Offices, Hotel
Stories: 31 floors
Structure: steel
(CFT:column)
HiDAX-s: 72 units

image:Resonance Curves of the Top Floor (Experimental Results)

Resonance Curves of the Top Floor (Experimental Results)

image:Top Floor Acceleration During Typhoon

Top Floor Acceleration During Typhoon

image:Free Vibration Waves Obtained Through Statistical Analysis Using Observed Records

Free Vibration Waves Obtained Through Statistical Analysis Using Observed Records