It was first brought up in our meeting on April 1st, where it was stated that the bridge landings may have to be raised “slightly” to accommodate the new bridge design. I was thinking on the order of 3” – 4” which possibly could have been accommodated. In our meeting of last Thursday, the 8th, the bridge landings now were being raised 2 feet above the previous design, hardly what one would consider “slightly”. Without having a set of park plans immediately available to review the proposed landings, paths and associated grading at that time to see if it was feasible, I said I would look into whether retaining walls would be able to solve the grade changes. I was also unaware that UDR had completed the walls, fencing and on-site walkways at that corner of the Savoye One building that are impacted by this bridge landing. On Friday afternoon, I received a hand sketch from Albert Halff that showed their reasoning and basis for raising the bridge and landings. I reviewed this design on Monday and it became apparent to me that raising these landings will create additional problems, and thus the email stating my concerns about the current bridge design. The attached photos show the Savoye One building corner nearest where the bridge landing will be installed (the bridge landing is actually attached to this corner of the walls). Note that the current proposed elevation by Albert Halff for the bridge landings would be at the exact same height as the retaining wall shown. I think further thought and discussion is needed. ________________________________ From: Lea Dunn [mailto:ldunn@addisontx.gov] Sent: Tuesday, April 13, 2010 3:46 PM To: Bruce Dunne; Nancy Cline; Clay Barnett; 'echristiansen@halff.com' Cc: Tom Lamberth Subject: RE: Vitruvian Park - South Pedestrian Bridge Bruce: I appreciate and understand your concerns but it would have been better if you had raised them during our preliminary meetings with Halff when this subject was discussed. Please be prepared to discuss and review this issue at our Thursday meeting so that we can finalize our decision and move forward. If you have any questions, please give me a call. Thanks, Lea Lea Dunn Deputy City Manager 972-450-7037 ldunn@addisontx.gov From: Bruce Dunne [mailto:bdunne@icon-engineers.com] Sent: Monday, April 12, 2010 7:04 PM To: Lea Dunn; Nancy Cline; Clay Barnett Cc: Tom Lamberth Subject: Vitruvian Park - South Pedestrian Bridge During our bridge meeting last Thursday, Albert Halff had proposed raising the abutments and adjacent grading by 2 feet to accommodate the “off-the-shelf” bridge that they had chosen. This was in order to provide 2 feet of freeboard above the 100 year flood elevation. I said I would look at the grading along the creek embankment and the existing Savoye One building to see if the grade change could be accommodated, thinking we would be able to construct some retaining walls to make up the extra two feet of grade change. After further thought, I remembered why the bridge was set at the elevations currently shown on the park drawings. The initial design intent for the bridge was to be a thin, sleek profile. Victor Lissiak looked into the pre-fab bridges and found that you cannot get one that is 150 feet long without the structure being nearly 3 feet thick from top of pavement to bottom of the beam. That is the reason why we chose to pay Victor an additional fee to design the bridge from scratch in order to have a profile more on the order of 8” thick. That said, it would be very difficult and expensive to redesign the abutments and associated grading to raise the bridge 2 feet as proposed. Savoye One has an existing retaining wall immediately adjacent to the abutment landing on the northwest side of the creek. If the bridge is raised, the abutment and landing would be higher than this retaining wall. In addition, the proposed jogging path would need to be constructed as a handicap ramp on each side of the abutment, complete with handrails, and designed with a switchback or a serpentined path in order to accommodate the difference in grade. I think we need to investigate further options for this bridge that will not raise the grades that are currently in place. BRUCE F. DUNNE, P.E. President icon Consulting Engineers, Inc. Bicentennial Financial Center 250 W. Southlake Blvd., Suite 117 Southlake, Texas 76092 Phone: (817) 552-6210 Fax: (817) 552-3126 Mobile: (817) 707-9711 ****************************************************************************************************************** This e-mail and any files or attachments transmitted with it contains Information that is confidential and privileged. This document may contain Protected Health Information (PHI) or other information that is intended only for the use of the individual(s) and entity(ies) to whom it is addressed. If you are the intended recipient, further disclosures are prohibited without proper authorization. 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