BDTM.109 - Sound Barrier Design
Wednesday, January 05, 2022 at 2:08:55 PM

To all:

Please be advised that the subject Bridge Design Technical Memorandum (BDTM) has been approved by the Bridge Design Engineer Administrator and published on the DOTD Bridge Design Section website for implementation at:

The BDTM "active" index has been updated and posted.

BDTM Summary:

This BDTM publishes a Bridge Design and Evaluation Manual (BDEM) revision, which adds Section 15 Design of Sound Barriers. The new BDEM Section 15 is attached to the BDTM.

The new BDEM Section 15 supplements AASHTO LRFD Bridge Design Specifications, 9th Edition Section 15 by adding DOTD design policy for Sound Barriers. The industry has sound barriers that have been tested in accordance with MASH Test Level 4 (TL-4). The new BDEM Section 15 DOTD design policy addresses and incorporates these tested systems, and includes the following main points (further summarized in the BDTM):

· Defines sound barriers as being MASH TL-4 or Non-MASH TL-4.
· Requires sound barriers to meet MASH TL-4, and provides the conditions where Non-MASH TL-4 sound barriers may be permitted pending an approved Design Waiver.
· Provides design and plan detailing guidance, including requiring designers to coordinate with Environmental Section, Environmental Document, Noise Study, Districts, and all other DOTD Sections to determine all design, construction, access and maintenance requirements for the construction project and for the District during sound barrier service life.
· All of the above bullets are delineated in terms of structure-mounted and ground-mounted sound barriers.

We are also in the process of updating our Sound Barrier NS Item specification to address the MASH testing and other requirements, such as design, construction, drainage, maintenance, aesthetics, etc.

This email notification and BDTM are distributed to all DOTD in-house and consultant bridge designers.

This email notification is copied to those copied on the BDTM, and to Consultant Contracts Services staff in order to distribute the e-mail and BDTM to consultant firms on the DOTD solicitation list. If you are listed as the Principle-In-Charge for a consultant firm, please inform your design staff of this BDTM.

Kelly M. Kemp, P.E.
Assistant Bridge Design Administrator
Section 25 - Bridge and Structural Design Section - Unit 8
LA Dept. of Transportation and Development
Office: (225) 379-1809

Please do not reply to this e-mail from MyDOTD. The originating e-mail account is not monitored by Consultant Contract Services (CCS). If you need assistance with the information in this email, please contact Kelly Kemp directly.