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HomeMy WebLinkAbout181214_Engineer's Field Report #1Engineer’s Field Report Client:City of Renton Project:Allura at Tiffany Park – Cantilevered Concrete Retaining Wall Contractor: 728 134th St SW, Suite 200 Everett, WA 98204 Ph: 425 741-3800 Fax: 425 741-3900 www.reidmiddleton.com Project No:262017.070 Page 1 of 5 Date:December 11, 2018 Time:9:00 AM / PM to 10:00 AM / PM Weather:Light Rain Temp:51 F to 51 F Est % Completion:100% (wall)Conformance with Schedule:UNKNOWN Contractor Work Force and Equipment (including subcontractors): None. Narrative (day’s operations, contractor production, unusual conditions or problems encountered, discussions, deficiencies noted/corrected, inspections performed, etc.): Present at Site: Ann Fowler, City of Renton Patrick Decaro, City of Renton Brian Moon, Reid Middleton Purpose of Visit: To observe cracks in an approximately 160’ long, 20’ high cantilevered reinforced concrete retaining wall that was constructed approximately 3 months ago. See Photo 1. Observations: 1. Near -vertical cracks were observed in the exposed face of the retaining wall at approximately 8 to 16 feet spacing the entire length of the wall. Most of the cracks appear to run full height and occur randomly in the wall, although some cracks appear to emanate from 3” diameter weep holes at the bottom of the wall. See Photo 2. 2. Similar cracks were observed in the concrete railing/parapet at the top of the retaining wall. See Photo 3. 3. Observed cracks range from hairline in width to larger (3 to 15 mils). Moisture stains are visible through some of the cracks. See Photo 4. 4. Finish grade at the bottom of wall is in close proximity to the weep holes and in some instances the weep holes are below finish grade and obscured from sight. See Photo 5. 5. Some subsidence of the landscaped soil was observed at the top of the wall at the northwest end. See Photo 6. Information or Action Required: 1. Cracks appear to be the result of normal shrinkage of concrete. No observed indications of distress were observed in the wall at this time. 2. Drawings provided to us by the City of Renton indicate that vertical construction joints are required in the wall at 20-feet maximum spacing and that horizontal reinforcement in the wall is to be terminated at the joints. It does not appear that construction joints were installed in accordance with the drawings. A single vertical expansion joint was observed in the wall at approximately mid-length of the wall. This expansion joint is not identified on the provided drawings. Engineer’s Field Report Client:City of Renton Project:Allura at Tiffany Park – Cantilevered Concrete Retaining Wall Contractor: 728 134th St SW, Suite 200 Everett, WA 98204 Ph: 425 741-3800 Fax: 425 741-3900 www.reidmiddleton.com Project No:262017.070 Page 2 of 5 3. Cracks do not appear to require any remedial action at this time although cracks should be monitored for additional growth. Cracks wider than hairline may result in moisture infiltration and become a source for reinforcing bar corrosion over the useful life of the wall. 4. Reid Middleton will install a crack-width gauge on the face of the wall so that the City of Renton can monitor the wall periodically and determine if cracks continue to grow over time. 5. We recommend that finish grade at bottom of wall be adjusted to keep weep holes clear of obstructions and debris. Disclaimer: The comments described here were based from a limited site visit performed to review general conformance with the plans and details. This site visit is not to be interpreted as an official inspection, nor is it intended to verify or direct contractor means or methods. Inspection should be provided by the independent inspection agency or the building official, as required by the project specifications and local jurisdictions. Report By: Brian Moon, SE Engineer’s Field Report Client:City of Renton Project:Allura at Tiffany Park – Cantilevered Concrete Retaining Wall Contractor: 728 134th St SW, Suite 200 Everett, WA 98204 Ph: 425 741-3800 Fax: 425 741-3900 www.reidmiddleton.com Project No:262017.070 Page 3 of 5 Photo 1. Elevation of wall (looking northwest) Photo 2. Typical crack in wall. Engineer’s Field Report Client:City of Renton Project:Allura at Tiffany Park – Cantilevered Concrete Retaining Wall Contractor: 728 134th St SW, Suite 200 Everett, WA 98204 Ph: 425 741-3800 Fax: 425 741-3900 www.reidmiddleton.com Project No:262017.070 Page 4 of 5 Photo 3. Typical cracking in railing/parapet wall. Photo 4. Moisture stain at crack. Engineer’s Field Report Client:City of Renton Project:Allura at Tiffany Park – Cantilevered Concrete Retaining Wall Contractor: 728 134th St SW, Suite 200 Everett, WA 98204 Ph: 425 741-3800 Fax: 425 741-3900 www.reidmiddleton.com Project No:262017.070 Page 5 of 5 Photo 5. Finish grade partially blocking weep hole. Photo 6. Soil subsidence at northwest end of wall.