Anti-Vibration & Noise Reduction

   Urbanization is a necessary way for the development of modern cities featured by population density and large number of motor vehicles. In recent years, with the increasing investment of infrastructure construction such as highways and railway, vehicle noise has become the main source of noise pollution which has an adverse impact on the daily life of communities. It has attracted great attentions from the government and communities how to improve driving experience, reduce motor vehicle noise and decrease the vibration of motor vehicles on the surrounding buildings.

  

   For bridge expansion joint, Datong INC. has developed GT-Flex Finger Joint for small movement and GT-Rotation Finger Joint for large movement.

  

   GT-Flex Finger Joint dramatically increased the strength and rigidity of the expansion joint system through integrating modular expansion joint with finger joint to form a type “T” finger joint. The leg of the finger can improve the strength and rigidity of joint. And boltless connecting of joint and adjacent structure makes the anchorage more reliable. The continuous finger support can reduce the impact of vehicles, resulting in noise reduction. Based upon large amount of tests, the GT-Flex finger joints can have a noise reduction effect up to 5dB(A) compared to modular joints.

   This joint, which is a cantilever type, may be uneconomical because it means a thicker steel plate. Typically, it is recommended to use for bridge longitudinal movement less than 160mm.

   GT-Flex Finger Joint has been certified by China Highway and Transportation Society (CHTS), with a conclusion “Reach international standard and recommend to form an industry standard with the Ministry of Transport”. It has been exported to many countries and applied in viaduct project of Shanghai middle ring line and traffic hub projects of Chengdu Expo City in Sichuan.

   GT-Rotation Finger Joint is an innovative and patented product. GT-Rotation is designed for finger joints for the simultaneous application of longitudinal and transverse movement, vertical and transverse rotation.

   GT-rotation finger joint is a combination of finger joint and spherical bearing. The finger plate can provide the longitudinal movement and improve driving experience, reduce traffic noise and decrease the vibration. And the spherical bearing provides the rotation about two axes and transverse movement. Since the supported structure of finger, this joint can be used for bridge longitudinal movement up to 3000mm.

   GT-rotation finger joint has been applied in a number of projects such as Jinan Changqing Yellow River Bridge in Shandong Province with a maximum movement capacity of 880mm and Nanning Liangqing Bridge in Guangxi Province with a movement range of 560mm.


   For bridge bearing, Datong Inc. has developed GT- Damping structural bearing for anti-vibration and noise reduction purpose by combining alloy damping materials with structure bearing.

   The vibration frequency of bridge structure due to traffic load is about 30Hz. The alloy damping material has superior performance in anti-vibration for low frequency vibration.

   In order to verify that the influence of alloy damping material for vibration, we have performed the experiments on rubber, alloy damping material and mild steel, respectively. From the test analysis, the alloy damping material have the most effective for anti-vibration, which can reduce the vertical load up to 46% and have a damping ratio 3 times of mild steel.

   GT-damping structure bearing has been applied in the ring road highway of Tianfu New Area in Sichuan province.