Application of AASHTO LRFD Specifications to Design of Sound Barriers

Overview

The current design criteria for sound barriers are based on the AASHTO Standard “Guide Specifications for Design of Sound Barriers” dated 1989 and interims through 2002. The content of the AASHTO Guide Specifications for design of sound barriers is not consistent with the requirements of the AASHTO LRFD bridge design specifications. The load and load combinations of the AASHTO LRFD section 3.4.1 do not conform to the ones specified in AASHTO guide specifications article 1.2.1 and 1.2.2. The vehicular impact load and load factors used for design of sound barriers adjacent to roadways are different from the ones required by LRFD Specifications. The LRFD design guidelines for sound barriers shall include all applicable loads, load combinations, and limit states relevant to sound barriers. Primary loads for design of sound barriers are wind under strength limit state, earthquake and vehicular impact loads under extreme event limit state. The objective of this research was to develop specifications and commentary for the design of sound barriers to be incorporated in the AASHTO LRFD Bridge Design Specifications.