BDTM.112 Swing Span Maximum Starting Torque
Wednesday, April 12, 2023 at 6:36:21 AM

To all:

1. The subject Bridge Design Technical Memorandum (BDTM) has been approved by the Bridge Design Engineer Administrator and is published on the DOTD Bridge Design Section website at:

http://wwwsp.dotd.la.gov/Inside_LaDOTD/Divisions/Engineering/Bridge_Design/Pages/Technical-Memoranda.aspx


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

BDTM Summary:
This BDTM publishes a revision to LADOTD Bridge Design and Evaluation Manual (BDEM), Part II, Volume 2, Section 5.4.3, with red line and clean copies attached to the BDTM. Revisions are summarized as follows:

· The wind load to be used for the determination of swing span movable bridge Maximum Starting Torque is reduced from the previous value of 10 psf minimum to 7 psf minimum.
· The commentary is revised to direct designers to ASCE 7 for wind load calculation.
· The background for this revision is addressed in commentary C5.4.3 (attached).

2. This notification email and BDTM are:
· Distributed to all DOTD in-house and consultant bridge designers.
· Copied to those copied on the BDTM.

3. This email requests the copied Consultant Contracts Services staff to distribute this e-mail and BDTM to consultant firms on the DOTD solicitation list.

4. This email requests consultant firm Principle-In-Charge to inform your design staff of this BDTM.

Thanks,
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
DOTD Internal Quick Dial: 3-1809

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.