10-4. From: Christiansen, Eric [mailto:echristiansen@halff.com] Sent: Wednesday, June 01, 2011 12:54 PM To: Eric T. Little Cc: 'Brian J. LaFoy' ; Barnett, Clay ; Nick Jacob Subject: RE: Bella Bridge Meeting Eric, The Bella Bridge deck cracking issue is not a structural concern; it is an issue of long-term durability and maintenance. I understand that Clay is reviewing the use of the Sika overlay product to determine if it addresses the Town’s concerns. Having spoken with Clay earlier today, I know that he will arrive at a solution as soon as practical. Eric C. Eric S. Christiansen, P.E., SECB Senior Structural Engineer HALFF ASSOCIATES, INC. 1201 North Bowser Road Richardson, Texas 75081 Office 214-346-6284 Cell 972-955-2996 Fax 214-739-0095 www.halff.com From: Eric T. Little [mailto:ELittle@udr.com] Sent: Friday, May 27, 2011 9:09 AM To: Christiansen, Eric Cc: 'Brian J. LaFoy'; Barnett, Clay; Nick Jacob; 'brusk@ndmce.com' Subject: FW: Bella Bridge Meeting Eric, See the email below from Brian. We need your opinion on this matter so we can bring it to a close. Thanks, Eric From: Brian J. LaFoy [mailto:blafoy@ndmce.com] Sent: Friday, May 27, 2011 9:07 AM To: 'Clay Barnett'; Eric T. Little Cc: Nick Jacob; Brad Rusk Subject: Bella Bridge Meeting Clay: Bill Light called me yesterday after our meeting. He called to ask me if I really thought the cracking on the bridge warranted the broadcast overlay system. I was clear to him that I had not taken a position on a particular repair system and that I was simply providing The Town and UDR with information to consider with both systems so that they are aware of any "side effects" of each system based on my experience. In summary, I told him what I had already expressed to you and Eric (Little) which is the following: 1. It is my opinion that the Sikadur 55 SLV is an appropriate product to use as crack healer/sealer for the size and quantity of cracking on the bridge. However, if used only in the cracks, I do not believe the appearance of a bridge that is full of patched cracks will be acceptable to The Town and UDR. In my experience, although the product comes in a clear material, you will still see the patched cracks and with the amount of cracking present, I think it will look awful. 2. If they use the Sikadur 55 SLV as a flood coat, which is really how it is intended, then I think you will still accomplish the goal of sealing the cracks and it will look better than just sealing the cracks. The downside to this, in my opinion, is that it can sometimes look "blemishy" over time and have an inconsistent color. Further, as I expressed yesterday, my concern is having the potential for a reduction is skid resistance. Bill indicated to me yesterday that TxDOT uses this system on various interstate highway bridges as an approved product. I don't know that that necessarily changes my concern for a reduction in skid resistance over time - it just means TxDOT doesn't consider it significant enough to be a concern. Further, I have no opinion at this point as to cause of the cracks since I have not been asked to evaluate anything. That is really Eric's (Christiansen) call. However, if he feels that the result of the cracking is a reduction in durability of the bridge deck, then I do not feel the Sikadur 55SLV is appropriate because it is not meant to address durability. 3. So after going through the sequence above: IF, it is a durability issue in Eric's opinion, then I would probably lean toward the broadcast system. If it is not, then The Town and UDR need to just weight the options they've been presented as far as appearance and success of the the product and make a decision. The broadcast system, in my opinion, will look look and accomplish not only sealing the cracks but improving the durability of the bridge deck. But I believe the cost is about 3 times that of the flood coat (assuming a double application). I've done single applications with broadcast overlays but not with Sika products - with their competitor. Bill suggested calling you and seeing if you wanted to go out and look at the bridge he mentioned that has the flood system on it. I told him I thought that would be a good idea. So if he hasn't called you already, he will. Also, maybe it would be helpful for me and Eric (Christiansen) to talk to arrive at the best recommendation for this problem. His opinion on the cause and effect (is it a durability issue) of the cracks really has an impact on the product selection in my opinion. In summary, this was my conversation with Bill yesterday. Let me know if you have any further direction for me at this point. Brian J. LaFoy, P.E. Vice President Nathan D. Maier Consulting Engineers, Inc. 8080 Park Lane, Suite 600 Dallas, Texas 75231 Ph. 214-739-4741 / Fax 214-739-5961 blafoy@ndmce.com