MAR APR MAY JUN JUL AUG

VIBRATION CONTROL OF STRUCTURES 3 APRIL 2015

Instructor Course PRESENTED BY:

CHIEW SHING MEI LIEW KOK KEI MUHAMMAD NAIM BIN MAZELAN

111447 111458 113595

TAIPEI 101, TAIWAN

PRESENTATION OUTLINES

Understanding of vibration control systems of structures

Principles associated with mass damper Principles associated with HMD Background of Yokohama Land Mark Tower Application of Hybrid Mass Damper in the

Yokohama Land Mark Tower Summary

In earthquake engineering: A set of technical means aimed to MITIGATE SEISMIC IMPACTS in building and non-building structures for enhancing their seismic fitness. (Wikiversity).

How to control: 1. Dissipate wave energy inside a superstructure e.g. dampers 2. Disperse the wave energy between a wider frequency range 3. Absorb the resonant portions e.g. mass damper Types of vibration control: 1. Passive control (TMD, TLD, viscous fluid and friction, base isolation) 2. Active control (AMD, HMD) 3. Semi-active control (combines features of active and passive control systems)

VIBRATION CONTROL SYSTEMS

Now: Understanding of vibration control systems of structures Next: Background of Yokohama Land Mark Tower

In earthquake engineering: A set of technical means aimed to MITIGATE SEISMIC IMPACTS in building and non-building structures for enhancing their seismic fitness. (Wikiversity).

How to control: 1. Dissipate wave energy inside a superstructure e.g. dampers 2. Disperse the wave energy between a wider frequency range 3. Absorb the resonant portions e.g. mass damper Types of vibration control: 1. Passive control (TMD, TLD, viscous fluid and friction, base isolation) 2. Active control (AMD, HMD) 3. Semi-active control (combines features of active and passive control systems)

Working principles of mass damper: Is a device mounted on structures such as buildings or bridges to reduce

the amplitude of the structures due to the vibrational motions induced by periodic or non-periodic dynamic loading.

Operates effectively to prevent internal discomfort and damage as well as the outright structural failures.

Installed mass damper moves in opposition to the resonance frequency oscillations of the structure by means of pendulum, spring or fluid.

Mass damper that counter-reacts the movement of building guarantees the safety of buildings when subjected to strong wind blow or light seismic wave.

TUNED MASS DAMPER (TMD)

Now: Principles associated with TMD Next: Principles associated with TMD (Con’t)

Response force

Legend

Applied vibrational force

These passive vibration control systems have been widely utilized in many high-rise building structures particularly those located at seismically active zone. These include Taipei 101 at Taiwan and One Rincon Hill at U.S. A.

TUNED MASS DAMPER (TMD)

Now: Principles associated with TMD (Con’t) Next: Principles associated with HMD

Tuned liquid damper (One Rincon Hill)

Pendulum tuned mass damper (Taipei 101)

HMD - Combination of a passive tuned mass damper (TMD) and an active control actuator. Control actuator is used in conjunction with TMD to increase the efficiency

of the HMD as well as its robustness. HMD depends partly on the natural frequency of a structure unlike an

AMD that is independent of the natural frequency. In overall, the added device adopted could reduce the structural response

relies mainly on the natural motion of TMD. Energy and forces required for operating a typical HMD are far less than a

fully active mass damper system of comparable performance.

HYBRID MASS DAMPER (HMD)

Now: Principles associated with HMD Next: Principles associated with HMD (Con’t)

Concept of a HMD (Spencer and Soong, 1999)

Application of HMD system in Sendagaya INTES building in Tokyo (1991): HMD effectively reduces the response at the fundamental mode by 18% and 28% for translation and torsion motions respectively.

HYBRID MASS DAMPER (HMD)

Now: Principles associated with HMD (Con’t) Next: Background of Yokohama Land Mark Tower

Location of Sendagaya INTES in map

11TH

Spencer and Soong (1999) Sendagaya INTES

YOKOHAMA LAND MARK TOWER,

JAPAN

Now: Background of Yokohama Land Mark Tower Next: Background of Yokohama Land Mark Tower (Con’t)

BACKGROUND Located at Minato Mirai 21 (district of Yokohama city). Five-stars hotel (603 rooms), 48 floors of shops, restaurants, clinic and offices, a 360-degree Sky Garden observatory station at 69th floor – Main usage: Hotel and Offices. Completed in 1993 and it had been known as the tallest building in Japan before it was surpassed by other buildings . Currently the 4th tallest structure in Japan. 2 tuned dampers are located 282m (71st Floor) above ground level. Currently has the world’s 2ND fastest elevator-traveling at 45 km/h.

Location of Yokohama

GENERAL STRUCTURAL INFORMATION:

YOKOHAMA LAND MARK TOWER,

JAPAN

Now: Background of Yokohama Land Mark Tower (Con’t) Next: Background of Yokohama Land Mark Tower (Con’t)

Building Type Skyscraper (Tall Building)

Main Structural System Trussed tube (Framed Tube Structure)

Main Structural Materials Structural steel and Reinforced concrete (RC)

Facade System (Material) Curtain wall (Granite)

Design Requirement (Vibrational Control

System)

Earthquake-proof Structure (Hybrid Mass Damper)

Rankings Global Ranking #95 Tallest in the World Regional Ranking #43 Tallest in Asia National Ranking #2 Tallest in Japan City Ranking #1 Tallest in Yokohama

YOKOHAMA LAND MARK TOWER, JAPAN

Now: Background of Yokohama Land Mark Tower (Con’t) Next: Application of HMD in Yokohama Land Mark Tower

APPLICATION OF HMD IN YOKOHAMA LAND MARK TOWER

Now: Application of HMD in Yokohama Land Mark Tower Next: Application of HMD in Yokohama Land Mark Tower (Con’t)

Two 170 – tonnes of multi-step pendulum HMD were installed in the Landmark Tower at first floor of the building’s penthouse to improve residential habitability. Each unit HMD contained an additional pendulum mass installed in the centre of a three-nested steel structure with the three frames connected by triplicating wire ropes. The HMD arranges an actuator and a damper in parallel. Since the damper dissipates vibration energy, a certain degree of reliability is ensured, even though the failure could be generated by active system.

Multistage Pendulum in Land Mark Tower

APPLICATION OF HMD IN YOKOHAMA LAND MARK TOWER

Now: Application of HMD in Yokohama Land Mark Tower (Con’t) Next: Application of HMD in Yokohama Land Mark Tower (Con’t)

It automatically becomes operational and switched between an active control state and a passive control state as directed by the sway of the building when the system senses accelerations in excess of 0.02 m/s^2. An active system with many motors driven ball screw can move the pendulum in two directions and tune it from a period of 6 s to 4.3 s through the use of a natural period regulator in order to correspond to natural modes of the tower.

DUOX System adopted in Landmark Tower

APPLICATION OF HMD IN YOKOHAMA LAND MARK TOWER

Now: Application of HMD in Yokohama Land Mark Tower (Con’t) Next: Application of HMD in Yokohama Land Mark Tower (Con’t)

Variable orifice dampers were installed between each frame to insure stability and safety.

The damping coefficient is 3,000 Ns/cm when the device stops and 300 Ns/cm while the system is functioning, which corresponds to the optimum damping coefficient for a passive TMD. The efficiency of the system allowed designers to use 20% of the mass that would have been required in a passive tuned mass damper system.

Yokohama Land Mark Tower

APPLICATION OF HMD IN YOKOHAMA LAND MARK TOWER

Now: Application of HMD in Yokohama Land Mark Tower (Con’t) Next: Summary

The hybrid mass damper uses 20% of the energy input that have been required from an active mass driver.

The end result is a system that increases the equivalent structural damping to more than 10 %.

This hybrid system can reduce until 50% of vibrations induced by wind and moderate earthquakes. Yokohama Land

Mark Tower

SUMMARY

Now: Summary Next: References and Ending

High-rise building structures are susceptible to vibrational motions due to the seismic impact from earthquake and the laterally acting wind force. Vibration control systems become utmost important for such

structures to have mitigated from damage caused by ground seismic waves and wind load.

Vibration control systems can be classified into passive control, active control and semi-active control which enhance the building seismic fitness. Yokohama Landmark Tower implemented Hybrid Mass Damper as its vibration control system. HMD is the combination of a tuned mass damper and the control actuator which is used to increase the efficiency of HMD and its robustness. In Yokohama Landmark Tower, HMD operates automatically and switches between active control state and passive control state when excess acceleration is detected. The hybrid system can reduce until 50% of vibrations induced by wind and moderate earthquake.

We referred to the following: http://web-japan.org/atlas/architecture/arc10.html http://en.japantravel.com/view/yokohama-landmark-tower http://www.emporis.com/buildings/105181/yokohama-

landmark-tower-yokohama-japan http://www.ce.tuiasi.ro/~bipcons/Archive/80.pdf

REFERENCES

Now: Introduction to the selected full scale structure Next: Vibrational control system adopted in Yokohama Landmark tower

THE END THANK YOU FOR YOUR KIND

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