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HomeMy WebLinkAbout6101 PHEASANT CT - CORRESPONDENCE - 2/1/1998AKM Engineering Consultants, Inc. Mr. David B. Higgins Long & Jaudon, P.C. February 1, 1998 1600 Ogden Street Project No. Denver, Colorado 80218 96-2864-F Subject: Repair Recommendations Homeowners: David Munn and Bonnie Munn Asido Address: 6101 Pheasant Court, Lot 1, Paragon Point Subdivision, Filing 43, Fort Collins, Colorado Court Case: Munn v. The Genesee Company, Inc. File Reference No.: 0112-2604 Reference: Soil and Foundation Investigation, Prepared by CTL Thompson, Inc., Job No. 26,867, Dated December 16, 1997 Mr. Higgins: The following recommendations are made to replace the basement concrete floor slab with a structural floor and underpin the existing foundation walls with new piers. Also included are recommendations to install a new perimeter drain system and construct a new concrete front porch. The basement structural floor framing plan is designed based on the assumption that the subject structure was constructed in accordance to the foundation plans prepared for the subject residence by Foundation Engineering Consulting Engineers, Job No. 1713Z-1-1d-1, dated September 3, 1993. The superstructure framing members such as floor joists, headers, beams, columns, etc. were not designed or checked by this office. The structural floor framing plan is designed based on the assumption that the existing foundation walls were constructed to support lateral pressure from the foundation backfill material. No investigation was performed to determine the stability of the foundation walls. Due to the expansive soils known to exist in this area and the limitations listed above, there are no guarantees regarding the future performance of the structure, including the new structural floor. THE CONTRACTOR SHALL INSPECT THE PREMISES AND SHALL NOTIFY THE ENGINEER OF ANY DISCREPENCIES PRIOR TO START OF CONSTRUCTION. 1. A copy of this report and the building permit card shall remain on -site at all times. 14A West Dry Creek Circle • Littleton, Colorado 80120 Phone (303) 730-6816 • Fax (303) 730-8091 February 1, 1998 Project No. 96-2864-F Page 2 2. The cleaning and storage of material in the subject residence shall be performed by others. 3. The contractor shall schedule a pre -construction meeting with the homeowner, engineer, contractor, and a representative of The Genesee Company. 4. Contractor shall take necessary precautions to minimize dust in the upper levels of the residence. 5. Contractor shall take necessary precautions not to damage the landscaping material. Contractor shall take pictures and document the existing landscaping and shall re -store any damaged landscaping to its original condition. 6. Contractor shall perform the above project in accordance to standard practice. 7. This report does not list all procedures and materials necessary to complete this project. Contractor shall be responsible to provide all materials and services necessary to complete the project. Concrete Slabs on Grade: 1. All exterior concrete slabs that are replaced shall have a minimum compressive strength of 3,500 p . s . i . in 28 days and have minimum 1-1/4 inch deep control joints at a maximum of 8 feet on center. All exterior concrete slabs that are replaced shall be isolated from the exterior of the residence with a minimum of 1/2 inch expansion material. 2. Remove and replace the front entry concrete sidewalk. The new concrete sidewalk shall be constructed on thoroughly compacted fill and shall be isolated from the new driveway concrete slab with minimum of 1/2 inch expansion material. 3. Remove and replace the driveway and the garage concrete floor slab and excavate backfill material as necessary to install new piers and perimeter drain. The new floor slabs shall be isolated from the foundation walls and superstructure with a minimum of 1/2 inch expansion material. Provide control joints at a maximum of 10 feet on center in the garage floor slab and driveway. Provide a control joint in the garage floor slab, approximately 2 feet away from the foundation walls. 4. Remove and replace the existing rear concrete patio with a new concrete patio slab at its original dimensions. The new concrete patio shall be isolated from the foundation walls and superstructure and shall be constructed in accordance to the detail on Sheet S-1. February 1, 1998 Project No. 96-2864-F Page 3 Re -leveling Residence: 1. Install 24" square cribbing and hydraulic jacks (20 tons minimum) under the existing foundation walls at a maximum of 12 feet on center. 2. A foundation elevation survey shall be performed by this office prior to the re -leveling operation. 3. Re -level the foundation walls. At this point the contractor shall raise the lower sections of the foundation walls to meet the higher sections. This office should be notified to observe the foundation wall re -leveling. It may be necessary to excavate the foundation backfill material in order to re -level the foundation walls. 4. The steel columns supporting the first floor steel beam should be adjusted during the foundation re -leveling process to correct the racked doors in the upper levels. New Pier Construction: 1. Contractor shall locate all utility lines prior to drilling the new piers. 2. Install (34) new 10 and 12 inch diameter concrete piers in accordance to the details shown in the attached Sheet S-1. All new piers shall be drilled to a minimum depth of 30 feet, with a minimum penetration of 10 feet into competent bedrock. The final location of the new piers shall be field verified. The final depth of the new piers, pier length and bedrock penetration shall be inspected and approved by CTL Thompson, Inc-.. 3. New 10 inch diameter piers shall be reinforced with three #5 grade 60 reinforcing bars for the entire length of the pier. New 12 inch diameter piers shall be reinforced with three #6 grade 60 reinforcing bars. Reinforcing bars shall be caged 2 feet from the ends and a maximum of 6 feet on center. The concrete shall be placed in the pier hole immediately after the completion of the drilling operation if groundwater is encountered. 4. All concrete for the piers shall be pea gravel with a minimum compressive strength of 7000 p.s.i. in 28 days. All concrete shall be placed at a 6 to 7 inch slump. 5. The new piers should be connected to the existing foundation walls in accordance to the pier haunch details on Sheet S-1. Saw cut and remove the face of the foundation footing at the pier locations. 6. The Soil Engineer and a representative of this office should be notified to inspect the installation of the new piers to assure proper bedrock penetration and haunch construction. February 1, 1998 Project No. 96-2864-F Page 4 7. Install 6 inch void between the new piers under all the garage, crawlspace and basement foundation walls. Structural Floor Installation• 1. Provide temporary support for the furnace, water heater, and basement staircase. 2. Remove the existing basement concrete floor slab. The foundation walls should be braced using pipe jacks prior to the removal of the existing floor system. The contractor is fully responsible for providing adequate lateral supports for the basement foundation walls to avoid any lateral movement .of these -foundation Walls-. We are available to review the lateral support details upon request. 3. Remove and replace underground sewer pipes, as necessary in compliance with the current Uniform Building Codes (UBC). 4. Remove sufficient soil from the basement area to allow a minimum of 22 inches of air space below the new structural floor sheathing. S. Provide adjustable 3-1/2 inch, Schedule 40, steel pipe columns in accordance to sheets S-2 and S-3. The existing columns should be removed and the first floor system should be re -leveled prior to installing the new columns. The new steel columns under the structural floor shall be welded (1/4" fillet weld) to the steel plate embedded in the new caissons. The existing columns may be altered and reused as necessary. 6. Slope the soil under the foundation walls as indicated in the attached details. Special care should be taken not to change the recommended slope for the soil under the new structural floor. 7. Install a perimeter drain in the basement, crawlspace and garage areas in accordance to the perimeter drain details on Sheets S-2 and S-3. The final location of the sump pit shall be field verified by a representative of this office and the homeowner. The "Little Giant" Model 8-CBA or equal sump pump shall be installed in the new sump pit. 8. A new lateral "spider" drain system shall be installed in accordance to Sheet S-2 under all of the applicable exterior basement and garage foundation walls. Perforated pipes wrapped in gravel and a filtering membrane shall be installed under the existing basement foundation walls in an attempt to drain any trapped water in the exterior excavations into the new interior perimeter drain system. 9. Construct the basement structural floor as indicated in Sheets S-2 and S-3. The new floor shall consist of W6 x 9 steel joists spaced February 1, 1998 Project No. 96-2864-F Page 5 at 24 inches on center, unless otherwise noted. Construct double steel joists under the water heater. 10. Provide mechanical ventilation for the crawlspace under the new structural floor in accordance with the local building codes. The ventilation should be properly designed and should contain a minimum of two intake pipes and two exhaust fans (Fantech Model FR150 or equal). 11. Provide a simplified lighting system in the crawlspace area under the new structural floor. The crawlspace accesses should be installed in the structural floor in accordance to the details on Sheets S-2 and S-3. 12. Re -install the basement staircase so it is bearing on the structural floor. The elevation of the structural floor should be set so the existing basement staircase meets the Uniform Building Codes. Modify the bottom 3 feet of the framing walls around the staircase to compensate for the new structural floor. The final elevation of the basement structural floor must be verified by this office prior to construction. 13. Provide a metal drain pan under the water heater with a discharge pipe connecting to the floor drain. 14. Re -install the finishing material to its original condition. 15. The above repairs may cause cosmetic damage to the superstructure. The cosmetic damage should be repaired in a minimum of 45 to 60 days after the completion of the structural floor construction. Adjust and repair as necessary all doors, including the main garage door. General Recommendations: 1. Remove the existing front porch and replace with a new structural concrete porch constructed in accordance to the details on Sheet S-2. 2. Re -level the first floor near the south wall cantilever. Attach the cantilever -supporting double 2x10 beam to the existing first floor steel beams in accordance to the details on Sheet S-2. 3. All foundation wall cracks will be evaluated and any cracks greater than -1./32-of an inchshall- be epoxy -injected. 4. Remove and replace any damaged exterior brick veneer after completion of the foundation repairs. 5. Exterior surface of all exposed basement foundation walls shall be waterproofed prior to the backfilling operation. February 1, 1998 Project No. 96-2864-F Page 6 6. Backfill the excavation a minimum of 7 days after the placement of the concrete with non -expansive fill containing a minimum of 50 percent clay. The backfill material should have a low permeability rate and should be compacted to avoid future settlement. 7. The wood steps leading to the garage service door should be removed and replaced with "hinged" steps. 8. The surface grading around the residence should be improved to achieve a minimum slope of 10 percent in the first 10 feet away from the foundation walls. The first 10 feet (5 feet minimum on sides) of area surrounding the exterior foundation walls shall be covered with landscape fabric and decorative rock. Relocate any sprinkler heads which spray water within 10 feet of the foundation walls. Equip all downspouts and hose bibbs with concrete splash blocks a minimum length of 4 feet. The subject splash blocks shall slope downward and away from the foundation walls. Exposure of water to the foundation backfill material will apply exoas-aive lateral pressure on the foundation walls and structural floor, which may cause failure of the structural floor. 9. Relocate any sprinkler boxes or valves a minimum of 8 feet away from the foundation walls. A foundation elevation survey should be conducted at the time of the cosmetic repair construction. •. Contractor shall notify AKM Engineering Consultants, Inc. to perform the following observations: a. Pre -construction meeting with the homeowner, contractor, and a representative of the builder. b. A foundation elevation survey prior to slab removal. C. Foundation re -leveling observation. d. Pier installation observations. e. On -site observation after all the foundation walls have been exposed. f. Interior perimeter drain trench observation. g. Interior perimeter drain material observation. h. Structural floor observation prior to placement of the plywood sheathing. February 1, 1998 Project No. 96-2864-F Page 7 i. Front porch reinforcing observation prior to placement of concrete. j. Initial re -grading observation and meeting. k. Surface grading observation. 1. Final observation with the homeowner, contractor, and a representative of the builder after all repair work is completed. A final foundation elevation survey will be conducted at this time. LIMITATIONS• The opinions and comments rendered in this report are based solely upon information obtained from readily visible elements of the home (i.e., elements which do not require the removal of cladding, sheathing, or covering of any kind) unless specifically noted. As a result of these limitations, latent structural damages may exist which were not detected. Due to the limitations noted above and the expansive soils known to exist on this site, no warranties regarding the future performance of the structure including the repaired areas are expressed, implied, written or otherwise. The Client will hold harmless, indemnify and defend the Engineer from and against any and all claims arising out of the professional services we have provided. Please contact us if you have any questions regarding this report or if we can be of further assistance. AKM Engineering Consultants, Inc. `••K K=F' j • = 7 3 • _ q0 4,, Jch Rickauer, E.I.T. Ali C.// �,��� .E. Sta f Engineer Project neer