Eric, I will discuss this with Nancy. We are going to meet with Dallas County sometime next week. Perhaps we can discuss it with them. Thanks, Clay Barnett, P.E. Town Engineer Town of Addison 16801 Westgrove Drive Addison, TX 75001-2818 Office: (972) 450-2857 -----Original Message----- From: Christiansen, Eric [mailto:echristiansen@halff.com] Sent: Friday, March 19, 2010 11:21 AM To: Nancy Cline; Clay Barnett Subject: RE: Bridge Railing Height at Vitruvian Park Folks, How do you want to proceed? Is the Town still comfortable with the 42" pedestrian rail, or would you rather increase the height? Please let us know. Thanks, Eric Eric S. Christiansen, P.E., SECB, LEED AP Senior Structural Engineer HALFF ASSOCIATES, INC. 1201 North Bowser Road Richardson, Texas 75081 Phone 214-346-6284 Fax 214-739-0095 Cell 972-955-2996 www.halff.com From: Jonathan Toffer [mailto:JONATHAN.TOFFER@dallascounty.org] Sent: Thursday, March 18, 2010 1:20 PM To: Christiansen, Eric; Cline, Nancy S.; Barnett, Clay Cc: Tushar Solanki; Yashar Farahmand; Antoinette Bacchus; Alberta Blair Subject: RE: Bridge Railing Height at Vitruvian Park Eric, Thank you for sharing information related to the bridge railing height. AASHTO may have recently allowed for 42-inch tall railing heights, however due to the proposed bridge conditions and past experiences Dallas County strongly recommends additional consideration of taller railings to better protect the safety of both pedestrians and bicyclists. There will be a significant vertical drop-off from the proposed bridges. The decision to implement vertical bars on the proposed railings is an appropriate choice to discourage climbing on the railing. With the mixed-use, medium-density nature of this development there will likely be many diverse users (e.g. pedestrians, bicyclists, rollerbladers, skateborders) of the pathways on the bridges resulting in a greater potential for collisions. Taller railings would provide an additional measure of safety in the event that collisions do occur near the bridge edge. For several recent Dallas County led bike/ped projects, some including TxDOT involvement, railing heights of greater than 42-inches have been used. Attached is one photo from the White Rock Lake bridge during busy conditions showing the benefit of both the taller rail height (54-inch) and the inclusion of a rub rail. Will the proposed bridge railings also include rub rails? Various options could achieve a taller railing height while meeting other design considerations. The railing could be mounted to a curb to provide additional height to a 42-inch railing. The example in the attached photo "Railing on elevated concrete" demonstrates how the railing height can be increased with an elevated concrete base. One concern seems to be how taller railings could obstruct the views from the bridge. Please view the attached examples that illustrate how obstructions from taller rails can be minimized. While these are not intended to be perfect applications for this project these images should convey how obstructions from a taller railing can be minimized to preserve clear views from the bridge. Please let us know if you have any questions or would like any other examples to consider. Ultimately, if the design engineer and Town of Addison are both comfortable with the 42-inch railing height then the design can proceed with this specification since it at least meets the minimum railing height per AASHTO. Thanks, Jonathan Toffer Transportation Planner Dallas County Public Works 411 Elm Street, 4th Floor Dallas, Texas 75202 214.653.6417 ________________________________ From: Christiansen, Eric [echristiansen@halff.com] Sent: Friday, March 12, 2010 4:52 PM To: Yashar Farahmand Cc: Cline, Nancy S.; Barnett, Clay; sstrickland@addisontx.gov; Jonathan Toffer; Tushar Solanki Subject: Bridge Railing Height at Vitruvian Park Yashar, I appreciate your update. I'm curious if it would be helpful for the County to know where TxDOT stands on this issue. The 2007 edition of the AASHTO LRFD Bridge Design Specifications states in Section 13.9 that the minimum height of a bicycle rail should be 42" (See attached). This is different from previous editions which mandated the use of 54" tall rails. Eventually, TxDOT released a memo (See the second sentence of the second paragraph on page 2 of the second attachment) in April of 2009 that stated "bicycle-specific rails are no longer necessary with the recent reduction in minimum bicycle rail height from 54-inch to 42-inch." This action eliminated TxDOT pedestrian/bicycle rails that were taller than 42". In consideration of TxDOT's actions, Halff would recommended the 42" bicycle rail height for the Vitruvian Park project. Is it possible Dallas County would reconsider its position? Please let me know if we can be of further assistance. Sincerely, Eric Christiansen- Eric S. Christiansen, P.E., SECB, LEED AP Senior Structural Engineer HALFF ASSOCIATES, INC. 1201 North Bowser Road Richardson, Texas 75081 Phone 214-346-6284 Fax 214-739-0095 Cell 972-955-2996 www.halff.com From: Yashar Farahmand [mailto:Yashar.Farahmand@dallascounty.org] Sent: Friday, March 12, 2010 1:20 PM To: Cline, Nancy S.; Christiansen, Eric; Barnett, Clay Cc: sstrickland@addisontx.gov; Jonathan Toffer; Tushar Solanki Subject: Bridge Railing Height Afternoon All, After speaking with others here at the county, I found that the minimum railing height that the county is installing on other trail project bridges is 54" and as such that is what the county would request to see on the Vetruvian Bridges as well. Thank you Yashar Farahmand E.I.T. Dallas County Public Works 214-653-6176