| 英文摘要 |
In recent years, overpass projects have been frequently seen in the construction of freeways and expressways in our country and long-span or continuous beam bridges have been mostly adopted for new bridges, therefore the type and gap of expansion joints have become increasingly innovative and expansive, and the structure more complicated, resulting in more frequent and obvious damages of expansion joints. As for the maintenance and replacement of bridge expansion joints, it is not only difficult but also very dangerous to maintain traffic during work. Particularly, it is not easy to ensure maintenance quality working under open traffic stress, with vibration caused by traffic flow, and in a confined space. In the meantime, extremely high social cost and price will be paid for the maintenance work. Presently, the biggest problem that challenges driving safety and comfort lies in the unevenness or damage of the expansion joints on freeways and expressways, which not only cause noises affecting the living quality of residents on both sides of the road, but also decrease the comfort and safety of driving on freeways and expressways. In view of the fact that the bridge expansion joints on freeways and expressways have caused problems one after another, the residents along the line have repeatedly petitioned against the noise caused by cars driving pass the expansion joints, and the bumps and jumps produced by the expansion joints have caused discomfort to drivers passing by, it is necessary to make a thorough inquiry of the jumps and noises caused by the expansion joints. Content of the project includes collecting information on the control methods for expansion joints on freeways and expressways adopted by foreign countries, conducting low frequency noise measurement for overpass expansion joints on freeways and expressways, formulating improvement measures for our country based on measuring results, analyzing the type, number, and handling of petitions against noises caused by overpass expansion joints on freeways and expressways in our country, and proposing goals for regulations on improvement.
The achievements of the 2011 study of control methods and improvement measures on low frequency noise produced by land transportation system (overpass expansion joints) include:
1. Collected information on the control methods, noise properties, low frequency noise-related issues, noise mitigation measures, noise control techniques, noise measuring methods, and related regulations for overpass expansion joints on freeways and expressways in foreign countries.
2. Completed low frequency noise measurement for overpass expansion joints on freeways and expressways as follows:
(1)Measured low frequency noise of overpass expansion joints on freeways at 7 locations (totally 36 measurements) and statistically analyzed their results.
(2)Measured low frequency noise of overpass expansion joints on expressways at 6 locations (totally 22 measurements) and statistically analyzed their results.
3.Formulated improvement measures for our country based on measuring results and proposed countermeasures, control techniques, control methods, and improvement measures for overpass expansion joints on freeways and expressways.
4.Analyzed the type, number, and handling of petitions against noises caused by overpass expansion joints on freeways and expressways in our country, and proposed improvement regulations.
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