tailieunhanh - Sound Walls and Railings

Sound Walls and Railings Sound Walls Introduction • Selection Of Sound Walls • Design Considerations • Ground-Mounted Sound Walls • Bridge-Mounted Sound Walls • Independent Sound Wall Structures 62 Farzin Lackpour Parsons Brinckerhoff-FG, Inc. Bridge Railings Introduction • Vehicular Railings • Bicycle Railings • Pedestrian Railings • Structural Specifications and Guidelines for Bicycle and Pedestrian Railings Fuat S. Guzaltan Parsons Brinckerhoff-FG, Inc. Sound Walls Introduction Need for Sound Walls Population growth experienced during past decades in metropolitan areas has prompted the expansion and improvement of highway systems. As a direct result of these improvements, currently 90 million people in the United States live close to high-volume, high-speed highways | Lackpour F. Guzaltan . Sound Walls and Railings. Bridge Engineering Handbook. Ed. Wai-Fah Chen and Lian Duan Boca Raton CRC Press 2000 62 Sound Walls and Railings Farzin Lackpour Parsons Brinckerhoff-FG Inc. Fuat S. Guzaltan Parsons Brinckerhoff-FG Inc. Sound Walls Introduction Selection Of Sound Walls Design Considerations Ground-Mounted Sound Walls Bridge-Mounted Sound Walls Independent Sound Wall Structures Bridge Railings Introduction Vehicular Railings Bicycle Railings Pedestrian Railings Structural Specifications and Guidelines for Bicycle and Pedestrian Railings Sound Walls Introduction Need for Sound Walls Population growth experienced during past decades in metropolitan areas has prompted the expansion and improvement of highway systems. As a direct result of these improvements currently 90 million people in the United States live close to high-volume high-speed highways. Rush-hour traffic on a typical high-volume high-speed urban highway generates noise levels in the 80 to 90 dBA range. Within 50 to 100 yd 45 to 90 m from the highway due to absorption by the ground cover the noise level dissipates to about 70 to 80 dBA. This ambient noise level in comparison with a 50 to 55 dBA noise level in an average quiet house is very intrusive to the majority of people and should be further reduced to at least 60 to 70 dBA level by implementing noise abatement measures. Design Noise Levels In 1982 the Federal Highway Administration FHWA published the Procedures for Abatement of Highway Traffic Noise and Construction Noise in the Federal Aid Highway Program Manual and therein established the acceptable noise levels at the location of the receivers houses schools etc. after the installation of the sound walls. This publication regulates the average allowable noise levels L h and the peak allowable noise levels L10 h the noise level that is exceeded more than 10 of the given period of time used to measure the allowable noise .