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HomeMy WebLinkAboutObservation of Excavation 11.12.2025ca 01( KURTZ & ASSOCIATES INCORPORATED Structural Consultants 5012 County Road 154 Phone (970) 945-6305 Glenwood Springs, CO 81601 RECEIVED FIELD OBSERVATION REPORT GARFIELI3 COUNTY COMMUNITY DEVELOPMENT (2) Pages To: Bulldog Construction, LLC Date: 11 /1212025 Attn: Alejandro Adame Re: Boulder Retaining Walls 100 River Bend Way 934 River Bend Way Glenwood Springs, Co. Ironbridge Subdivision THE FOLLOWING WAS OBSERVED: The purpose of this field observation was to observe the completed construction of a set of two dry -stack boulder retaining walls adjacent to the residence. The boulder retaining walls were constructed on each side of a uncovered exterior stairway which creates access to the lower, basement level of the home at 934 River Bend Way. At this time the house construction is complete and the adjacent boulder retaining walls are complete. The basement level doorway has been recently saw -cut in the existing concrete basement wall. The stairway is built with stone treads and it extends from the driveway to the front wall of the home. The boulder walls are located between the attached garage and the entry porch. The garage extends 7'-8" out from the front wall of the home, and the entry porch is 5'-4" deep. I understand that the basement foundation walls have been stabilized by the installation of a hydraulically driven steel pier `under -pinning' system. I understand that the attached garage has a relatively shallow system of foundation walls and footings (i.e. `frost walIs'), and that the garage foundation walls are not `under -pinned.' I understand that the concrete entry porch is `under- pinned.' The home's entry faces west towards River Bend Way so that the two retaining walls border the north and south sides of the exterior stair. The top of the two boulder walls is approximately level and is just above the finish grade at the front of the home. The height of the walls varies linearly as the stair descends to the basement level. The maximum wall height = 8'4'. The walls are constructed with 18" to 20" diameter boulders, and the walls are not vertical. The walls are battered away from the stairs at 2 over 12 (horizontal over vertical). I understand that each wall is protected with a subgrade collection drain (i.e. a French drain), and that the collection drains are connected to the perimeter subsurface collection drain which serves the house. That collection drain system outflows to a storm sewer. Note that the significant batter reduces the 2 horizontal design earth pressure by almost 50%, Both the north boulder wall and the south boulder wall are well constructed and have been built with a below grade `French drain.' All aspects of the boulder wail construction, including the subgrade `French drain' are structurally acceptable. Nate that boulder retaining walls are, in general, relatively flexible when compared to reinforced concrete retaining walls. The boulder walls and the south wall of the garage should regularly monitored. (See attached partial plan.) Lateral movement of the boulder wall adjacent to the garage could lead to vertical displacement of the southwest corner of the garage foundation. It is my professional opinion that the boulder retaining walls, as constructed, are structurally appropriate, stable and structurally acceptable. �` V" a•e� L�11 4� O° k,n,1AY I[U yli 4r r" 1874� m • s . °1•a�1°°t�°f_ �Cf •f i da2 � s, �' BV d Job Code T By Date 1(1QT j p4j �af 7 CONSULTING ENGINEERS Checked -. SheetOf