stevey
Structural
- Feb 19, 2003
- 11
I am involved in a design process of an architecturally elaborate bridge, made up of both precast and CIP elements. The bridge is being designed and constructed by a State agency, but will be turned over to our City for ownership/maintenance upon completion.
My question regards recommendations for the surface finish for the bridge. The State agency has 3 progessive classes of finish which begins with general surface finish (essentially just removal of bulges, fins, rock pockets, etc.), Class 1 finish - general finish plus grinding and coating with latex paint, and Class 2 finish - all of the above plus an intermediate floating (i.e. sacking) of the surface before coating.
At the City, we typically don't paint our bridges because of (later) appearance and maintenance issues (i.e repainting), but we do sack the finish (a Class 2 finish, as above, but no paint). I would be satisfied with this finish type on this bridge, too, but the architect is very concerned that grinding by an over enthusiastic worker will remove or round over his sharp detail lines, and that the floating process would give a rough texture, and round over details even more.
Assuming we can address the architect's concerns by carefully spelling out the acceptable surface finish guidelines, I'm wondering if anybody has any experience/recommendations for the application of a pigmented surface sealer (probably concrete gray)in lieu of the paint? The majority of our surfaces would be the railings, and vertical faces of columns, piers, outside faces of girders, and fairly extensive modular approach walls. Would a pigmented sealer look OK? How long would these sealers last on surfaces that are not subject to traffic loads? We would also like some graffiti protection on the piers and approach walls, though. Incidentally, in our City and State we do not use salts for the infrequent snow/ice removal, so we don't need an elaborate protection system.
Any advice would be greatly appreciated.
Thanks.
Steve R. Yates
City of Portland Oregon
Office of Transportation Engineering
My question regards recommendations for the surface finish for the bridge. The State agency has 3 progessive classes of finish which begins with general surface finish (essentially just removal of bulges, fins, rock pockets, etc.), Class 1 finish - general finish plus grinding and coating with latex paint, and Class 2 finish - all of the above plus an intermediate floating (i.e. sacking) of the surface before coating.
At the City, we typically don't paint our bridges because of (later) appearance and maintenance issues (i.e repainting), but we do sack the finish (a Class 2 finish, as above, but no paint). I would be satisfied with this finish type on this bridge, too, but the architect is very concerned that grinding by an over enthusiastic worker will remove or round over his sharp detail lines, and that the floating process would give a rough texture, and round over details even more.
Assuming we can address the architect's concerns by carefully spelling out the acceptable surface finish guidelines, I'm wondering if anybody has any experience/recommendations for the application of a pigmented surface sealer (probably concrete gray)in lieu of the paint? The majority of our surfaces would be the railings, and vertical faces of columns, piers, outside faces of girders, and fairly extensive modular approach walls. Would a pigmented sealer look OK? How long would these sealers last on surfaces that are not subject to traffic loads? We would also like some graffiti protection on the piers and approach walls, though. Incidentally, in our City and State we do not use salts for the infrequent snow/ice removal, so we don't need an elaborate protection system.
Any advice would be greatly appreciated.
Thanks.
Steve R. Yates
City of Portland Oregon
Office of Transportation Engineering
