The URL can be used to link to this page

Home My WebLink AboutPermit Field Test & Inspection Report 2005-8-16 '.. -} <3 K & A Engineering, Inc. P.o. Box 23624, Eugene, OR 97402 521 Market St., Suite B, Eugene, OR 97402 (541) 684-9399 Voice (541) 684-9358 FAX pnginppring August 16, 2005 DMH Enterprises 780 S. 57th St. Springfield, OR 97478 Project: 187.05 Subject. Foundation soils Springfield building permit no. COM2005-00377 755 S. 58th S1. PURPOSE AND SCOPE As requested, K & A Engineering, Inc. has completed a limited evaluation of the subject project site. Our understanding is that a new duplex will be constructed at the site. Construction will consist of a conventionally framed structure supported by a conventional cast-in-place concrete spread footing foundation system. The purpose of our evaluation was to detennine the nature and extent of sOil at the site, provide on-site verbal recommendations for foundation pad construction and document our findings and recommendations in thIS report. The scope of our services included visits to the site for visual inspection during excavation, and a written report. FOUNDATION PAD PREPARATION General Site Conditions The project site is located on the east side of the street on a west-facing slope. The slope is not severe and the estimated gradient ranges from 20 to 25%. The slope surface was relatively uniform. There are no indications of slope movement en the site. The ground surface, prior to excavation, did not have a significant amount of vegetation. Subsurface Soil Conditions Soils at the east half of the site consisted of 1.5 to 2.0-feet of dark brown, damp, soft plastic silts over approximately over massive, hard tan/orange sandstone. In the west half the soils consisted of 1.5 to 2.0-feet of tan, damp, soft plastic silty fill over 0.5 to 1.0-feet of dark brown organic silty topsoil over 1.0 to 1.5-feet of dark gray, saturated, soft, highly plastic silt over decomposed or highly weathered tan/orange sandstone. Construction Construction of the foundation pad consisted of excavating and removing the overlying soft silts, topsoil, and highly plastic silt to undisturbed highly weathered tan/orange sandstone. The excavation resulted in three benches into the hillside in the foundation area. ^ . . n f) K & A Engineering, Inc. The upper two benches (in the east 2/3 of the foundation pad) bottomed into massive tan/orange sandstone at depths ranging from 3 to 4-feet. After removing all loose soil and rock, the benches were covered with a thin layer of dense-graded crushed aggregate to provide a smooth, level surface for footing construction. The lower bench (at the west 1/3 of the foundation pad) was excavated to a depth ranging from 3 to 4-feet since soft silty fills and soft highly plastic silts were encountered in this area. After removing all loose soil and rock, 3 to 4-feet of 5-inch open graded crushed quarry stone were placed in the excavation (for the west bench) and seated with the backhoe bucket. The 5-inch quarry stone was covered with 6 to 12-inches of 1 1/2-inch and %-inch minus dense-graded crushed aggregate, in 4-inch lifts, and compacted to provide a smooth, level surface for footing construction. We tested the crushed aggregate for dry density and have determined that the density exceeds 95% of maximum as determined by ASTM 0698. A copy of the fIeld test resu~s are attached to thIs report. - SUMMARY AND RECOMMENDATIONS General Suitability The foundation pad, as constructed, will provide excellent foundation support with no hazards associated with slope movement or heaving soils. We recommend acceptance of the foundation pad, as constructed, by the local building official. Drainage We recommend that a perimeter footing drain be installed along the east, north, and south sides of the foundation. The footing drain consists of a perforated drain pipe covered with at least 12-inches of drain rock that is enveloped in a separation geotextile. To construct the footing drain; 1. First placing the separation geotextile at footing level on the prepared foundation pad. The geotextile should run the length of the footing and be wide enough to wrap around the drainrock and still proVide a 12-inch minimum overlap at the top. 2. Next place the perforated drainpipe on the geotextlle with the perforations facing down. 3. Cover the top and sides of the drainpipe with drain rock. 4. Cover the dmin iOck with the separation geotextile, overlapping the fabric on top of the iOck a minimum of 12-inches. The footing drain should be placed as low as possible in the excavation, preferably at the base of the granular fill. We recommend that a drain be installed at the west edge of the coarse quarry stone fill to collect groundwater that may accumulate in the fill. This drain may consist of a solid drainpipe that extends into the quarry stone fill. All footing drains and the quarry stone drain should be routed to the city storm drain system. Project: 187.05 Client: OMH Enterprises 755 S. 58th St., Springfield, OR Page 2 of 3 August 16, 2005 K & A Engineering, Inc. I SPECIFICATIONS Foundation Drain Perforated drainpipe should consist rigid ADS 3000 Triple Wall pipe. The perforations should be placed down. The foundation drain should NOT be connected to the rdof drain unless the connection is made downhill of the foundation utilizing a backflow prevention device that prbhibits roof drainage from backing up into the foundation drain system. Drain Rock Drain rock should consist of clean, durable, 1 1f2-inch round rock. The rock should be placed over and to the side of the perforated pipe so that the pipe has a mimmJm of 12-inches of cover. The drain rock should be covered with separation geotextile Separation Geotextile Separation geotextile should be placed on the grade (at footmg level) prior to placement of the perforated pipe so that after the pipe is laid and drain rock place, the gedtextile can completely wrap around the drain rock. Separation geotextile shall consist of a polypropylene non-woven needle-punched fabric that is stabilized against degradation from ultraviolet light exposure (sunlight). The fabric should meet the specifications for Amoco ProPex 4535. LIMITATIONS OF THIS REPORT This report has been prepared for the exclusive use of DMH Enterprises and its subcontractors for the subject proposed structure. This geotechnical investigation, analysis, and recommendations meet the standards of care of competent geotechnical engineers providing similar services at the time these services were provided. We do not warrant or guarantee these recommendations, site surface, or subsurface conditions. Exploration test holes indicate sOil conditions only at specific locations (i.e. the test hole locations) to the depths penetrated. They do not necessarily reflect soiVrock materials or groundwater conditions that exist between or beyond exploration locations or limits. The scope of our services does not include construction safety precautions, techniques, sequences, or procedures, except as specifically reGommended in this r~port. QLli services should not be interpreted as an environmental assessment of site conditions. Thank you for the opportunity to be of service. Please call us if you have questions or need further assistance. Sincerely, ~:~~ Michael Remboldt, P.E. K & A Engineering, Inc. EXPIRES !,L(w ~ Project: 187.05 Client: DMH Enterprises 755 S. 58th St., Springield, OR Page 3 of 3 August 16, 2005 , , Density of Soil and Soil-Aggregates In-Place ASTM 02922 and 03017 Project: 187.05 Site Address: 755 S 58th Street Permit No: COM2005-00377 Date: 8/19/2005 Density Test Type1:/DT-4" Operator: I CCD Material Type:13/4" (-) Springfield Quarry Maximum Dry Denstiy, pcfl 141.0 Standardization and Reference Check A Density (Standard Deviations) (S.D.) 0.3 A Moisture, (S.D:) 0.19 Moist - - 01)' Density, Density, Water Compaction, Test No. pet per Content, % % Remarks 1 156.7 145.7 7.5 103.3% 2 150.1 141.6/ 6.0 100.4% 3 144.71 135.9' 6.51 96.4%1 4 147.51 139.1 6.1 98.7% I I I j I I j I j I I I I I I Average: 99.7% Std. Dev.: 2.93% 1 DIrect Transmission (DT) (specify deprh, in.) or Air Gap Backscatter (AGB) (specifiy(1)ouchable or (U)ntouchable mode Test performed using Seaman Nuclear Corp model C-300, SN 21113 Client DMH Enterprises Project 187.05 K & A Engineering, Inc. 8/19/2005