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Report (5) // Li&Z sck/azctc,' it G P�0 t c�t SoFutuons 1 -ncl July 16, 2008 americastire- 07 -01 -cms Discount Tire Co. 5310 E. Shea Blvd. Scottsdale, AZ 85254 -4700 dwainwright@discounttireco.com Attention: Dan Wainwright GEOTECHNICAL COMPLIANCE America's Tire: New Store — Tigard, Oregon Building Permit No. BUP 2007 -00448 This letter summarizes our observations of geotechnical aspects during construction of the new America's Tire store in Tigard, Oregon. Our services included observation of site stripping, cement amendment of fill, structural fill preparation, retaining wall footing subgrade preparation, retaining wall backfill preparation, building pad and footing subgrade preparation, parking area base rock preparation, and asphalt concrete density testing. Monitoring was completed on a part-time, on -call basis during the duration of construction, with our last visit for on -site work completed on July 7, 2008. Based on our observations, the aforementioned items were completed in general accordance with the intent of the project specifications and our recommendations. Our visits were documented in site visit reports which have been provided to the owner, engineer, and contractors and are attached to this letter. Please call if you have any questions. Sincerely, PROF ���0 F MOPE • Ryan White, MS, PE, GE oiflEGO>M o^' Senior Project Engineer r+44 55 9k N WN Don Rondema, MS, PE, GE !RENEWAI. OATt: L /24 t o I Principal cc: Kathy Peters, Discount Tire Co., kpeters @discounttireco.com Dana Korns, Discount Tire Co., dkorns @discounttireco.com Steve Beiser, Discount Tire Co., Steve.Beiser @discounttireco.com Reg Morris, Baker Construction, rmorris @bakerconstruct.com Todd Harnetiaux, Baker Construction, toddh @bakerconstruct.com Mike Dennis, Bones Construction, mike @bonesco.com . Craig Harris, AAI Engineering, craigh @aaieng.com Walter Barnett, City of Tigard, Walter @tigard - or.gov I/1 1112 7 Street, Oregon City, OR 97045 p 503.657.3487 f 503.722.9946 Gesoiu Ions I ncl SITE VISIT REPORT: Discount Tire - Tigard, Oregon americastire-07-0 1 -cms To: Dan Wainwright, Discount Tire Co., dwainwright @discounttireco.com Visit Date: January 18, 2008 Arrival Time: 2:30 pm Permit #: N/A Weather: 40 °, cloudy Subject: Stripping Observation I arrived on site as requested by Norm of Bones Construction (Bones). I met with Norm and Randy with Bones on- site. The purpose of our visit was to observe site stripping. Reg Morris with Baker Construction was not on -site during our visit. While on -site I discussed cement amendment and construction of the proposed retaining wall. Site Stripping In general, the thick root zone and topsoil had been removed from both the cut and fill areas. The location of the wall had not been staked (surveyor was on -site during our visit) and subsequently had not been stripped /excavated. Wall Construction Randy provided two documents associated with construction of the proposed retaining wall at the site. The wall will consist of a Lock and Load wall designed by David Hall for the wall contractor. The wall layout plan shows embedment of up to 0.8 feet of embedment for the entire length of the wall. Per the table provided with the wall cross - sections, embedment of the wall ranges from 12 inches to .2.5 feet depending on the slope at the toe of the wall. The embedments in the table are consistent with our recommendation of a horizontal offset of 5 feet from the face of the wall to the face of the slope. Due to the current wet conditions, I recommended covering the excavated subgrade with rock following excavation to protect the subgrades from water softening and disturbance. If soft or unsuitable soil conditions are encountered we should be contacted immediately and these areas should remain uncovered. Bones requested clarification on these embedments prior to excavation for the wall footing. I stated that the increasing embedments with steepening slope inclinations was consistent with our recommendations and that 0.8 feet of embedment, as shown on the plan, was not adequate. Further, grid lengths should be based on the total wall height, which includes the exposed height plus the embedment. Steps in the wall footing subgrade to match site topography will result in staggered grid elevations over the length of the wall depending on the total wall heights at those elevations. Cement Amendment Norm indicated that on -site soil would be moved to the fill area and amended in- place, without treating the subgrade where the fill thickness is greater than 1.5 feet. Norm was not aware of what percentage of cement was being proposed for amendment. Based on field observation, moisture contents of the on -site soil is likely on the order of 30 percent we will obtain samples for moisture testing during our next visit. With moisture contents of 30 percent we recommend using a minimum of 6 percent cement. The presence of surface water or wetter soil will likely require increasing this. This report presents opinions formed as a result of our observation of activities relating to geotechnical engineering services. We rely on the contractor to comply with the plans and specifications throughout the duration of the project irrespective of the presence of our representative. Our work does not include quality control, and contractors and subcontractors have no right to rely on our services and reports. Our work does not include supervision or direction of the contractor, the contractor's employees, or agents. Our firm is not responsible for site safety. 1/2 1 1 12 7'h Street, Oregon City, OR 97045 p 503.657.3487 f 503.722.9946 • • • • eo E So ions I ncl Limiting the loose fill thickness to the till depth is critical to achieving adequate mixing and cement content. We will return to the site as contacted to observe preparation of the retaining wall footing subgrade and cement amendment of on -site fill. n /M. ._ Ry. - hite, MS, PE, GE Senior Project Engineer cc: Reg Morris, Baker Construction, tba Todd Harnetiaux, Baker Construction, toddh @bakerconstruct.com Mike Dennis, Bones Construction, mike @bonesco.com Craig Harris, AA! Engineering, craigh @aaieng.com • This report presents opinions formed as a result of our observation of activities relating to geotechnical engineering services. We rely on the contractor to comply with the plans and specifications throughout the duration of the project irrespective of the presence of our representative. Our work does not include quality control, and contractors and subcontractors have no right to rely on our services and reports. Our work does not include supervision or direction of the contractor, the contractor's employees, or agents..Our firm is not responsible for site safety. 2/2 1112 7 Street, Oregon City, OR 97045 p 503.657.3487 f 503.722.9946 • hh 3 G e t opufions lncl SITE VISIT REPORT: Discount Tire - Tigard, Oregon americastire- 07- 01-cros To: Dan Wainwright, Discount Tire Co., dwainwright @discounttireco.com Visit Date: January 23, 2008 Arrival Time: 8:40 am Permit #: N/A Weather: 29 °, sunny Subject: Cement Amendment of Fill, Retaining Wall Footing Subgrade I arrived on site as requested by Norm of Bones Construction (Bones). I met with Norm and Randy with Bones, Reg Morris with Baker Construction, and Hugh O'neal with West Coast Road Recycling (WCRR) (cement amendment contractor) on -site. The purpose of our visit was to observe cement amendment of fill being placed and preparation of the retaining wall footing subgrade. Retaining Wall Footing Subgrade The retaining wall footing subgrade for the planned Lock - and -Load wall had been excavated to subgrade elevation. The exposed soil consisted of silt, clay, and severely weathered rock. In general, the subgrade was very stiff to hard based on penetration resistance with a field probe. Slow seepage was observed in a few areas along the back of the cut, which extended to the back of the planned geo- grids, and will be picked up by the wall drain. Based on our observations, the retaining wall footing subgrade has been prepared in general accordance with the intent of our recommendations. Cement Amendment of Fill When I arrived, an approximately 8 -foot wide flat bench had been "notched" into the site slope above the back of the retaining wall excavation. Cut soil from excavation of the retaining wall footing and building pad had been spread over the "upper" portion of the site for amendment. WCRR was spreading approximately 5 percent cement per square foot and tilling approximately 12 inches. The amended soil was being moved to the lower bench with an excavator, bladed to an approximate lift thickness of 12 inches, tracked with the dozer, and rolled with a vibratory, single -drum, pad -foot roller. Minor to no deflection of the amended soil was observed under the roller. During my visit, approximately 2 feet of fill had been placed and compacted on the lower bench. According to Norm, current plans would likely result in an additional 4 to 5 feet of fill placed. Returned to site 4:00 pm. When I returned, amended had been completed and all the excavated soil had been treated, placed and compacted. The dozer was being used to level out site grades and the large excavator was being used to "track -in" the surface of the amended fill. The slope behind the retaining wall excavation had been cut back into amended soil at approximately I H: I V. According to Norm, approximately I foot of on -site soil will be cut from the building pad and spread over the fill area tomorrow (Thursday) and amended in -place on Friday morning. Operating directly on the amended soils This report presents opinions formed as a result of our observation of activities relating to geotechnical engineering services. We rely on the contractor to comply with the plans and specifications throughout the duration of the project irrespective of the presence of our representative. Our work does not include quality control, and contractors and subcontractors have no right to rely on our services and reports. Our work does not include supervision or direction of the contractor, the contractor's employees, or agents. Our firm is not responsible for site safety. 1/2 1 1 12 7`" Street, Oregon City, OR 97045 p 503.657.3487 f 503.722.9946 Ge tE S c �olu ions I ncl without the full cure time (generally 4 days) could result in disturbance and require repair. Norm was aware of this. Disturbance could be reduced by pushing the next lift of soil out on an advancing pad. We will return to the site Friday morning to observe continued amendment. — 1 Ry. hite, MS, PE, GE Senior Project Engineer cc: Reg Morris, Baker Construction, tba Todd Harnetiaux, Baker Construction, toddh @bakerconstruct.com Mike Dennis, Bones Construction, mike @bonesco.com Craig Harris, AAI Engineering, craigh @aaieng.com • This report presents opinions formed as a result of our observation of activities relating to geotechnical engineering services. We rely on the contractor to comply with the plans and specifications throughout the duration of the project irrespective of the presence of our representative. Our work does not include quality control, and contractors and subcontractors have no right to rely on our services and reports. Our work does not include supervision or direction of the contractor, the contractor's employees, or agents. Our firm is not responsible for site safety. 2/2 1 1 12 7' Street, Oregon City, OR 97045 p 503.657.3487 f 503.722.9946 • G e t ch son ions I ncl SITE VISIT REPORT: Discount Tire - Tigard, Oregon americastire- 07- 0I-cros To: Dan Wainwright, Discount Tire Co., dwainwright @discounttireco.com Visit Date: January 25, 2008 Arrival Time: 9 :00 am Permit #: N/A Weather: 32 °, sunny Subject: Cement Amendment I arrived on site as requested by Norm of Bones Construction (Bones). I met with Norm and Randy with Bones, and Reg Morris with Baker Construction on -site. The purpose of our visit was to observe cement amendment of both fill being placed over the southern portion of the site and amendment of the subgrade in the cut areas on the northern portion of the site. Newly Amended Soil When I arrived I observed slow seepage at the corner of the building pad excavation where the deepest cut was. The cement spreader' and tiller had both gotten stuck prior to my arrival. Norm stated that the soft, wet soil would be spread over the amended area to the west, amended and tilled, then pushed back into the corner of the building pad. Following this initial amendment, the entire pad would likely be treated a second time. According to Norm approximately 12 to 18 inches of fill had been spread over the southern "fill area" yesterday. This soil included brown silt from the on -site cut and trench spoils from nearby. The trench spoils were gray and contained occasional debris such as plastic and wood. The trench spoils only made up a small percentage of the soil being amended and was primarily used in the southeastern corner, adjacent to the construction entrance. Approximately 5 percent cement was being spread over both the cut and fill areas and tilled to a depth of up to 18 inches. Following tilling, the amended soil was rough graded with a dozer and compacted using a single drum, vibratory pad -foot roller. Minor to no deflection was observed under the roller in the fill areas. Minor to moderate deflection was observed under the roller over the cut area (prior to excavating and replacing with amended soil). Based on our observations, the cement amendment is progressing as planned. The finished surface should be fine graded by either rolling with a smooth drum roller or track walking the surface. The amended areas should not be trafficked by construction equipment within four days of completion. Previously Amended Soil I evaluated the fill soil that was amended on Wednesday by probing the perimeter of the recently spread fill and the fill slope behind the cavation for the wall. The surface of the amended soil was very stiff to hard. the Ry hite, MS, PE, GE Senior Project Engineer cc: Kathy Peters, Discount Tire Co., kpeters @discounttireco.com Dana Korns, Discount Tire Co., dkorns@discounttireco.com Steve Beiser, Discount Tire Co., Steve.Beiser@discounttireco.com Reg Morris, Baker Construction, tba Todd Harnetiaux, Baker Construction, toddh@bakerconstruct.com Mike Dennis, Bones Construction, mike @bonesco.com Craig Harris. AAI Engineering, craigh @aaieng.com This report presents opinions formed as a result of our observation of activities relating to geotechnical engineering services. We rely on the contractor to comply with the plans and specifications throughout the duration of the project irrespective of the presence of our representative. Our work does not include quality control, and contractors and subcontractors have no right to rely on our services and reports. Our work does not include supervision or direction of the contractor, the contractor's employees, or agents. Our firm is not responsible for site safety. I/ 1 1 12 7`" Street, Oregon City, OR 97045 p 503.657.3487 f 503.722.9946 • e 5oiu ions 1ncl SITE VISIT REPORT: Discount Tire - Tigard, Oregon americastire- 07- 0I-cros To: Dan Wainwright, Discount Tire Co., dwainwright @discounttireco.com Visit Date: January 30, 2008 Arrival Time: 9:00 am Permit #: N/A Weather: 35 ° , rain Subject: Retaining Wall Rock Leveling Course I arrived on site as requested by Reg Morris of Baker Construction to observe preparation of the crushed rock leveling course for the new Lock - and -Load retaining wall. I met with Reg on -site. The building pad, parking area, and retaining wall subgrades had all been covered with crushed rock prior to my arrival. The leveling course for the retaining wall was generally 4 to 6 inches thick and well- keyed. Ponded water was present over the middle 20 percent of the wall and the entire lower (SW) corner of the wall excavation was full of water. The water should be removed from the excavation prior to starting wall construction. Based on our observations, the crushed rock leveling course for the retaining wall has been prepared in general accordance with the intent of our recommendations. We must be contacted to evaluate the retaining wall backfill when construction of the wall begins. We will return to the site as contacted. Ryan-White, MS, PE, GE Senior Project Engineer cc: Kathy Peters, Discount Tire Co., kpeters @discounttireco.com Dana Korns, Discount Tire Co., dkorns @discounttireco.com Steve Beiser, Discount Tire Co., Steve.Beiser @discounttireco.com Reg Morris, Baker Construction, tba Todd Harnetiaux, Baker Construction, toddh @bakerconstruct.com Mike Dennis, Bones Construction, mike @bonesco.com Craig Harris, AAI Engineering, craigh @aaieng.com • This report presents opinions formed as a result of our observation of activities relating to geotechnical engineering services. We rely on the contractor to comply with the plans and specifications throughout the duration of the project irrespective of the presence of our representative. Our work does not include quality control, and contractors and subcontractors have no right to rely on our services and reports. Our work does not include supervision or direction of the contractor; the contractor's employees, or agents. Our firm is not responsible for site safety. I/I 1 1 12 7 Street, Oregon City, OR 97045 p 503.657.3487 f 503.722.9946 • solu tions 1 nci SITE VISIT REPORT: Discount Tire - Tigard, Oregon americastire- 07- 01-cros To: Dan Wainwright, Discount Tire Co., dwainwright @discounttireco.com Visit Date: February 5, 2008 Arrival Time: 9:00 am Permit #: N/A Weather: 37 °, showers Subject: Retaining Wall Rock Leveling Course, Storm Detention Pipe Backfill I arrived on site as requested by Jeremy of Centerstone Corp. (retaining wall contractor) to observe the current conditions of the rock leveling course and surface water seepage into the wall footing area. I met with Jeremy and Steve Pfeifer of Centerstone Corp. on -site. While on -site I also observed preparation of the storm detention pipe backfill at the crest of the slope above the retaining wall footing excavation. Retaining Wall Leveling Course and Surface Water Seepage When I arrived on -site I observed that water was flowing through the retaining wall footing excavation toward the low corner. Centerstone had excavated a shallow trench along the back of the grid zone to help direct runoff. However, the wall footing subgrade appeared to slope to the face of the wall, which required lateral trenches to direct the water to the back trench. Due to soil slough from above, the presence of water, and the foot traffic in the footing excavation, there are localized areas where the rock has been contaminated with silt. • • In order to adequately compact the rock leveling course it will be necessary to remove the majority of the water from within the base rock. This is being accomplished with the aforementioned trench while pumping from the low corner of the excavation. Approximately 3 to 6 inches of additional rock is necessary to get the leveling course to top of rock grade according to Steve. Steve proposed installing a layer of clean, angular drain rock in the low area and capping it with 3 /4 -inch minus to bring that area to grade. In my opinion, this is a suitable approach provided the rock leveling course can be adequately compacted and "well- keyed ". We must be contacted to evaluate the rock leveling course when it is.at grade, prior to starting wall construction. Storm Detention Pipe Backfill While on -site I observed that the storm detention pipe was being backfilled with on -site silt, previously excavated from the trench. The pipe appeared to have been surrounded and capped with a thin layer of clean medium sand. The silt was being placed in lifts over the approximate 4 -ft wide trench and compacted using a trench wheel on an excavator. The moisture content of the silt was slightly wet of optimum (approximately 20 percent) and contained variable amounts of rock. Following placement and compaction of 2 lifts (approximately 10 to 12 inches total) of fill, I evaluated the stiffness by driving a 3 /4 -inch diameter field pin 12 inches with a 4 -lb hammer. Blow counts ranged from 5 to 6 indicating the silt fill had not been adequately prepared. I talked to both Herb and Brad of Bones Construction regarding the backfill materials and preparation. In my opinion it will be difficult to get adequate compaction of this material using a trench wheel. I recommended using thing lifts with some form of pad foot roller, which Brad stated they had nearby. This report presents opinions formed as a result of our observation of activities relating to geotechnical engineering services. We rely on the contractor to comply with the plans and specifications throughout the duration of the project irrespective of the presence of our representative. Our work does not include quality control, and contractors and subcontractors have no right to rely on our services and reports. Our work does not include supervision or direction of the contractor, the contractor's employees, or agents. Our firm is not responsible for site safety. 1/2 1 1 12 7 Street, Oregon City, OR 97045 p 503.657.3487 f 503.722.9946 • Ge Soiutions I ncl There is some risk using silt as backfill in this area during wet conditions. If the moisture content of the silt fill increase, adequate compaction will not be possible. I the stockpile or installed backfill gets wet as a result or rain or runoff, at least portions, if not the majority of, the material will need to be removed and replaced: If construction traffic will operate in this area, the silt backfill should be covered with a minimum of 24 inches of crushed rock. The above risks can be avoided by using clean granular material to backfill the full depth of the trench. We will return to the site as contacted. • Rya kite, MS, PE, GE Senior Project Engineer cc: Kathy Peters, Discount Tire Co., kpeters @discounttireco.com Dana Korns, Discount Tire Co., dkorns @discounttireco.com Steve Beiser, Discount Tire Co., Steve.Beiser @discounttireco.com Reg Morris, Baker Construction, tba Todd Harnetiaux, Baker Construction, toddh @bakerconstruct.com Mike Dennis, Bones Construction, mike @bonesco.com Craig Harris, AA! Engineering, craigh @aaieng.com • This report presents opinions formed as a result of our observation of activities relating to geotechnical engineering services. We rely on the contractor to comply with the plans and specifications throughout the duration of the project irrespective of the presence of our representative. Our work does not include quality control, and contractors and subcontractors have no right to rely on our services and reports. Our work does not include supervision or direction of the contractor, the contractor's employees, or agents. Our firm is not responsible for site safety. 2/2 1 1 12 r Street, Oregon City, OR 97045 p 503.657.3487 f 503.722.9946 6 solutions I ncl SITE VISIT REPORT: Discount Tire - Tigard, Oregon americastire- 07- 01-cros To: Dan Wainwright, Discount Tire Co., dwainwright @discounttireco.com Visit Date: February 5, 2008 Arrival Time: 3:30 pm Permit #: N/A Weather: 40 °, showers Subject: Storm Detention Pipe Backfill, Retaining Wall Construction I arrived on site as arranged with Herb of Bones Construction to evaluate preparation of the storm detention pipe backfill. While on -site I also observed construction of the retaining wall at the west end. Storm Detention Pipe Backfill When I arrived I observed that Herb was operating a small, dual drum, vibratory, pad -foot roller on the fill. As discussed, he stated the previously installed fill had been removed then placed and compacted in 6 inch lifts. The backfill consisted of on -site silt that was slightly wet of optimum moisture. I evaluated the surface of the fill, which was near subgrade elevation, at two locations by driving a 3 /4 -inch diameter field pin I2- inches with a 4 -lb hammer. Resulting blow counts were 10 for each test. Based on our observations and testing, the backfill is being installed in general accordance with the intent of our recommendations. Retaining Wall Construction Construction of the wall had started at the low point at the western corner with the first course of blocks in place. Crushed rock was being compacted in the counterfort zone with medium sand behind that. A layer of geogrid had been placed under the wall over the rock leveling course. The backfill had not been compacted during my visit. The 4 -inch diameter socked, perforated drain pipe had been placed at the back of the grid zone with fabric underneath and surrounded in angular drain rock. I recommended lapping the fabric over the top of the drain rock per the detail in the wall design. We will return to the site as contacted. Rya kite, MS, PE, GE Senior Project Engineer cc: Kathy Peters, Discount Tire Co., kpeters @discounttireco.com Dana Korns, Discount Tire Co., dkorns @discounttireco.com Steve Beiser, Discount Tire Co., Steve.Beiser @discounttireco.com Reg Morris, Baker Construction, tba Todd Harnetiaux, Baker Construction, toddh @bakerconstruct.com Mike Dennis, Bones Construction, mike @bonesco.com Craig Harris, AAI Engineering, craigh @aaieng.com This report presents opinions formed as a result of our observation of activities relating to geotechnical engineering services. We rely on the contractor to comply with the plans and specifications throughout the duration of the project irrespective of the presence of our representative. Our work does not include quality control, and contractors and subcontractors have no right to rely on our services and reports. Our work does not include supervision or direction of the contractor, the contractor's employees, or agents. Our firm is not responsible for site safety. I 1 1 12 7 Street, Oregon City, OR 97045 p 503.657.3487 f 503.722.9946 Ge tech� solutions I ncl SITE VISIT REPORT: Discount Tire - Tigard, Oregon americastire- 07- 01-cros To: Dan Wainwright, Discount Tire Co., dwainwright @discounttireco.com Visit Date: February 6, 2008 Arrival Time: 2:00 pm Permit #: N/A Weather: 42 °, showers Subject: Retaining Wall Construction, Storm Detention Pipe Backfill I arrived on site as arranged with Jeremy of Centerstone Corp. (retaining wall contractor) to observe wall construction and with Herb of Bones Construction to evaluate the storm detention pipe backfill. I met with Herb and Reg Morris of Baker Construction on -site. Retaining Wall Construction When I arrived on -site I observed that third course of blocks had been placed at the southwest corner. Crushed rock was being compactd in the counterfort zone, with medium sand being used behind that. This is the first course of blocks that continues east across the majority of the wall. Blocks had only been placed approximately '/, of the way across the wall. The Centerstone crew stated that the middle section of wall, as shown on the wall layout detail, steps up. Because the subgrade is continuous, crushed rock structural fill is being used through this area. I contacted Steve to discuss this approach. He planned on being at the site tomorrow to evaluate this option with the possibility of adding blocks along this section of wall. Based on our observations, the wall is being constructed in accordance with our recommendations. Storm Detention Pipe Backfill While on -site I observed that the storm detention pipe had been backfilled to grade. Excavation of the rock surfacing confirmed it was at least 12 inches thick at the surface. According to Reg, the silt soil being used was placed in approximately 6 inch thick lifts and compacted with a small remote control dual drum pad -foot roller. The moisture contents appeared consistent with those observed yesterday afternoon and appear to be slightly above optimum. I evaluated the silt fill by driving a' /4 -inch diameter field pin 12 inches with a 4 -lb hammer. Resulting blow counts average approximately 10 for the three tests completed over the eastern 2/3 of the pipe backfill. Based on our observations and testing, the silt backfill observed has been prepared in general accordance with the intent of our recommendations. We will return to tJ as tacted. Ryan ite, MS, PE, GE Senior Project Engineer cc: Kathy Peters, Discount Tire Co., kpeters @discounttireco.com Dana Korns, Discount Tire Co., dkorns @discounttireco.com Steve Beiser, Discount Tire Co., Steve.Beiser @discounttireco.com Reg Morris, Baker Construction, tba Todd Harnetiaux, Baker Construction, toddh @bakerconstruct.com Mike Dennis, Bones Construction, mike @bonesco.com Craig Harris, AA! Engineering, craigh @aaieng.com This report presents opinions formed as a result of our observation of activities relating to geotechnical engineering services. We rely on the contractor to comply with the plans and specifications throughout the duration of the project irrespective of the presence of our representative. Our work does not include quality control, and contractors and subcontractors have no right to rely on our services and reports. Our work does not include supervision or direction of the contractor, the contractor's employees, or agents. Our firm is not responsible for site safety. I/I 1 1 12 7`" Street, Oregon City, OR 97045 p 503.657.3487 f 503.722.9946 G ex oiutions Incl SITE VISIT REPORT: Discount Tire - Tigard, Oregon americastire- 07- 01-cros To: Dan Wainwright, Discount Tire Co., dwainwright @discounttireco.com Visit Date: February 7, 2008 Arrival Time: 1:20 pm Permit #: N/A Weather: 48 ° , showers Subject: Retaining Wall Construction I arrived on site as arranged with Reg Morris of Baker Construction to observe continued construction of the Lock - and -Load retaining wall at the site. I met with Steve Pfeifer of Centerstone and the Centerstone crew on -site. When I arrived on -site I observed that third course of blocks had been placed across the entire width of the wall. The eastern end was being backfilled during my visit. Crushed rock was being compactd in the counterfort zone, with medium sand being used behind that in the backfill /grid zone. Blocks had been placed all the way across the wall in lieu of removing 12 blocks at the middle of the wall as discussed yesterday with Steve. I evaluated both the crushed rock and sand backfill at four locations along the wall by driving a 3 /4 -inch diameter field pin 12 inches with a 4 -lb hammer. Resulting blow counts were between 10 and 11. Based on our observations and testing, the wall backfill tested to -date has been prepared in general accordance with the intent of our recommendations and the specifications. We will return to the site as contacted. Ryan kite, MS, PE, GE Senior Project Engineer cc: Kathy Peters, Discount Tire Co., kpeters @discounttireco.com Dana Korns, Discount Tire Co., dkorns @discounttireco.com Steve Beiser, Discount Tire Co., Steve.Beiser @discounttireco.com Reg Morris, Baker Construction, tba Todd Harnetiaux, Baker Construction, toddh @bakerconstruct.com Mike Dennis, Bones Construction, mike @bonesco.com Craig Harris. AAI Engineering, craigh @aaieng.com This report presents opinions formed as a result of our observation of activities relating to geotechnical engineering services. We rely on the contractor to comply with the plans and specifications throughout the duration of the project irrespective of the presence of our representative. Our work does not include quality control, and contractors and subcontractors have no right to rely on our services and reports. Our work does not include supervision or direction of the contractor, the contractor's employees, or agents. Our firm is not responsible for site safety. I/I 1 1 12 7 Street, Oregon City, OR 97045 p 503.657.3487 f 503.722.9946 • G solutions I ncl SITE VISIT REPORT: Discount Tire - Tigard, Oregon americastire- 07- 01-cros To: Dan Wainwright, Discount Tire Co., dwainwright @discounttireco.com Visit Date: February I I, 2008 Arrival Time: 1:20 pm Permit #: N/A Weather: 45 ° , cloudy Subject: Retaining Wall Construction I arrived on site as arranged with Reg Morris of Baker Construction to observe continued construction of the Lock - and -Load retaining wall at the site. I met with Reg on -site. When I arrived on -site I observed that the majority of the wall was backfilled and compacted to a level of 4 blocks. I evaluated the compacted backfill by driving a 3 /4 -inch diameter field pin 12 inches with a 4 -lb hammer. Resulting blow counts indicated the backfill was being prepared in general accordance with the intent of our recommendations. Based on our observations and testing, the retaining wall backfill is being prepared in general accordance with the intent of specifications and our recommendations. We will return to the site tomorrow afternoon to evaluate continued backfill preparation for the wall. "(—... Rya hite, MS, PE, GE Senior Project Engineer cc: Kathy Peters, Discount Tire Co., kpeters @discounttireco.com Dana Korns. Discount Tire Co., dkorns @discounttireco.com Steve Beiser, Discount Tire Co., Steve.Beiser @discounttireco.com Reg Morris, Baker Construction, tba Todd Harnetiaux, Baker Construction, toddh @bakerconstruct.com Mike Dennis, Bones Construction, mike @bonesco.com Craig Harris, AAI Engineering, craigh @aaieng.com • This report presents opinions formed as a result of our observation of activities relating to geotechnical engineering services. We rely on the contractor to comply with the plans and specifications throughout the duration of the project irrespective of the presence of our representative. Our work does not include quality control, and contractors and subcontractors have no right to rely on our services and reports. Our work does not include supervision or direction of the contractor, the contractor's employees, or agents. Our firm is not responsible for site safety. I/I 1 112 7 Street, Oregon City, OR 97045 p 503.657.3487 f 503.722.9946 Ge solutions 1 ncl SITE VISIT REPORT: Discount Tire - Tigard, Oregon americastire- 07- 0I -cros To: Dan Wainwright, Discount Tire Co., dwainwright @discounttireco.com Visit Date: February 8, 2008 Arrival Time: 3:30 pm Permit #: N/A Weather: 48 °, showers Subject: Retaining Wall Construction I arrived on site as arranged with Reg Morris of Baker Construction to observe continued construction of the Lock - and -Load retaining wall at the site. I met with Steve Pfeifer of Centerstone and the Centerstone crew on -site. When I arrived on -site I observed that the majority of the wall was backfilled to a level of 2 blocks, with the 3 row of blocks in -place with the backfill remaining to be compacted. I evaluated the compacted backfill at the east end of the wall where the next lift of backfill had not yet been spread. The backfill was evaluated by driving a 3 /4 -inch diameter field pin 12 inches with a 4 -lb hammer. Resulting blow counts indicated the backfill was being prepared in general accordance with the intent of our recommendations. - The geo -grid exposed at the top of the counter at the western corner had only been placed perpendicular to, the southern portion of the wall and not the western edge. Steve stated that there should be grid in both directions • and directed the crew to add a second layer of grid in the correct orientation. Two new lengths of geo -grid replaced the original and the area would be backfilled. We will return to the site Monday afternoon as requested by Marcos with Centerstone. Rya hite, MS, PE, GE Senior Project Engineer cc: Kathy Peters, Discount Tire Co., kpeters @discounttireco.com Dana Korns, Discount Tire Co., dkorns @discounttireco.com Steve Beiser, Discount Tire Co., Steve.Beiser @discounttireco.com Reg Morris, Baker Construction, tba Todd Harnetiaux, Baker Construction, toddh @bakerconstruct.com Mike Dennis, Bones Construction, mike @bonesco.com Craig Harris, AAI Engineering, craigh @aaieng.com This report presents opinions formed as a result of our observation of activities relating to geotechnical engineering services. We rely on the contractor to comply with the plans and specifications throughout the duration of the project irrespective of the presence of our representative. Our work does not include quality control, and contractors and subcontractors have no right to rely on our services and reports. Our work does not include supervision or direction of the contractor, the contractor's employees, or agents. Our firm is not responsible for site safety. I /1 1 1 12 7th Street, Oregon City, OR 97045 p 503.657.3487 f 503.722.9946 G Solutions I ncl tffl ch SITE VISIT REPORT: Discount Tire - Tigard, Oregon americastire- 07- 0I-cros To: Dan Wainwright, Discount Tire Co., dwainwright @discounttireco.com Visit Date: February II, 2008 Arrival Time: 1:20 pm Permit #: N/A Weather: 45 °, cloudy Subject: Retaining Wall Construction I arrived on site as arranged with Reg Morris of Baker Construction to observe continued construction of the Lock - and -Load retaining wall at the site. I met with Reg on -site. When I arrived on -site I observed that the majority of the wall was backfilled and compacted to a level of 4 blocks. I evaluated the compacted backfill by driving a' /cinch diameter field pin 12 inches with a 4 -lb hammer. Resulting blow counts indicated the backfill was being prepared in general accordance with the intent of our recommendations. Based on our observations and testing, the retaining wall backfill is being prepared in general accordance with the intent of specifications and our recommendations. We will return to the site tomorrow afternoon to evaluate continued backfill preparation for the wall. – 75 — L AJA 7‘ Ryan,White, MS, PE, GE Senior Project Engineer cc: Kathy Peters, Discount Tire Co., kpeters @discounttireco.com . Dana Korns, Discount Tire Co., dkorns @discounttireco.com Steve Beiser, Discount Tire Co., Steve.Beiser @discounttireco.com Reg Morris, Baker Construction, tba Todd Harnetiaux, Baker Construction, toddh @bakerconstruct.com Mike Dennis, Bones Construction, mike @bonesco.com Craig Harris, AAI Engineering, craigh @aaieng.com This report presents opinions formed as a result of our observation of activities relating to geotechnical engineering services. We rely on the contractor to comply with the plans and specifications throughout the duration of the project irrespective of the presence of our representative. Our work does not include quality control, and contractors and subcontractors have no right to rely on our services and reports. Our work does not include supervision or direction of the contractor, the contractor's employees, or agents. Our firm is not responsible for site safety. I 1 1 12 7` Street, Oregon City, OR 97045 p 503.657.3487 f 503.722.9946 • G olutions I ncl SITE VISIT REPORT: Discount Tire - Tigard, Oregon americastire-07-0 I -cms To: Dan Wainwright, Discount Tire Co., dwainwright @discounttireco.com Visit Date: February 12, 2008 Arrival Time: 1:30 pm Permit #: N/A Weather: 45 °, cloudy Subject: Retaining Wall Construction I arrived on site as arranged with Reg Morris of Baker Construction to observe continued construction of the Lock - and -Load retaining wall at the site. When I arrived on -site I observed that the majority of the wall was backfilled and compacted to a level of 5 blocks. The 6th row was being set and leveled during my visit. I evaluated the compacted backfill by driving a 3 /4 -inch diameter field pin 12 inches with a 4 -lb hammer. Resulting blow counts of indicated the backfill was being prepared in general accordance with the intent of our recommendations. Based on our observations and testing, the retaining wall backfill is being prepared in general accordance with the intent of specifications and our recommendations. We will return to the site tomorrow afternoon to, evaluate continued backfill preparation for the wall. n Rya kite, MS; PE, GE Senior Project Engineer cc: Kathy Peters, Discount Tire Co., kpeters @discounttireco.com Dana Korns, Discount Tire Co., dkorns @discounttireco.com Steve Beiser, Discount Tire Co., Steve.Beiser @discounttireco.com Reg Morris, Baker Construction, tba Todd Harnetiaux, Baker Construction, toddh @bakerconstruct.com Mike Dennis, Bones Construction, mike @bonesco.com Craig Harris, AAI Engineering, craigh @aaieng.com This report presents opinions formed as a result of our observation of activities relating to geotechnical engineering services. We rely on the contractor to comply with the plans and specifications throughout the duration of the project irrespective of the presence of our representative. Our work does not include • quality control, and contractors and subcontractors have no right to rely on our services and reports. Our work does not include supervision or direction of the contractor, the contractor's employees, or agents. Our firm is not responsible for site safety. I /1 1 1 12 7th Street, Oregon City, OR 97045 p 503.657.3487 f 503.722.9946 G o t lutions I ncl SITE VISIT REPORT: Discount Tire - Tigard, Oregon americastire- 07- 01-cros To: Dan Wainwright, Discount Tire Co., dwainwright @discounttireco.com Visit Date: February 13, 2008 Arrival Time: 12:40 pm Permit #: N/A Weather: 45 ° , cloudy Subject: Retaining Wall Construction I arrived on site as arranged with Reg Morris of Baker Construction to observe continued construction of the Lock - and -Load retaining wall at the site. I met with Reg on -site When I arrived on -site I observed that the majority of the wall was backfilled and compacted to a level of 6 blocks. The 7th row was being set and leveled during my visit. I evaluated the compacted backfill by driving a 3 /4 -inch diameter field pin 12 inches with a 4 -lb hammer. Resulting blow counts of indicated the backfill was being prepared in general accordance with the intent of our recommendations. According to Marcos with Centerstone, the backfill is being compacted with both the large, hand - operated vibratory plates and a small smooth drum roller. Based on our observations and testing, the retaining wall backfill is being prepared in general accordance with the intent of specifications and our recommendations. We will return to the site tomorrow afternoon to evaluate continued backfill preparation for the wall. Ryan) hite, MS, PE, GE Senior Project Engineer cc: Kathy Peters, Discount Tire Co., kpeters @discounttireco.com Dana Korns, Discount Tire Co., dkorns @discounttireco.com Steve Beiser, Discount Tire Co., Steve.Beiser @discounttireco.com Reg Morris, Baker Construction, rmorris @bakerconstruct.com Todd Harnetiaux, Baker Construction, toddh @bakerconstruct.com Mike Dennis, Bones Construction, mike @bonesco.com Craig Harris, AAI Engineering, craigh @aaieng.com This report presents opinions formed as a result of our observation of activities relating to geotechnical engineering services. We rely on the contractor to comply with the plans and specifications throughout the duration of the project irrespective of the presence of our representative. Our work does not include quality control, and contractors and subcontractors have no right to rely on our services and reports. Our work does not include supervision or direction of the contractor, the contractor's employees, or agents. Our firm is not responsible for site safety. I/I 1 1 12 7`" Street, Oregon City, OR 97045 p 503.657.3487 f 503.722.9946 G e solutions 1 ncl SITE VISIT REPORT: Discount Tire - Tigard, Oregon americastire- 07- 0I-cros To: Dan Wainwright, Discount Tire Co., dwainwright @discounttireco.com Visit Date: February 14, 2008 Arrival Time: 1:45 pm Permit #: N/A Weather: 50 °, partly cloudy Subject: Retaining Wall Construction I arrived on site as arranged with Reg Morris of Baker Construction to observe continued construction of the Lock - and -Load retaining wall at the site. I met with the Centerstone (retaining wall subcontractor) crew on -site When I arrived on -site I observed that the majority of the wall was backfilled and compacted to a level of 7 blocks. The 8th row was being set and leveled during my visit. I evaluated the compacted backfill by driving a 3 /4 -inch diameter field pin 12 inches with a 4 -lb hammer. Resulting blow counts indicated the backfill was being prepared in general accordance with the intent of our recommendations. According to Marcos with Centerstone, the backfill is being compacted with both the large, hand - operated vibratory plates and a small smooth drum roller. Based on our observations and testing, the retaining wall backfill is being prepared in general accordance with the intent of specifications and our recommendations. We will return to the site tomorrow to evaluate continued backfill preparation for the wall. n Ryan kite, MS, PE, GE Senior Project Engineer cc: Kathy Peters, Discount Tire Co., kpeters @discounttireco.com Dana Korns, Discount Tire Co., dkorns @discounttireco.com Steve Beiser, Discount Tire Co., Steve.Beiser@discounttireco.com • Reg Morris, Baker Construction, rmorris @bakerconstruct.com Todd Harnetiaux, Baker Construction, toddh @bakerconstruct.com Mike Dennis, Bones Construction, mike@bonesco.com Craig Harris, AAI Engineering, craigh@aaieng.com This report presents opinions formed as a result of our observation of activities relating to geotechnical engineering services. We rely on the contractor to comply with the plans and specifications throughout the duration of the project irrespective of the presence of our representative. Our work does not include quality control, and contractors and subcontractors have no right to rely on our services and reports. Our work does not include supervision or direction of the contractor, the contractor's employees, or agents. Our firm is not responsible for site safety. l 1 1 12 T Street, Oregon City, OR 97045 p 503.657.3487 f 503.722.9946 6 s ex to ch olutions Incl SITE VISIT REPORT: Discount Tire - Tigard, Oregon americastire- 07- 0I-cros To: Dan Wainwright, Discount Tire Co., dwainwright @discounttireco.com Visit Date: February 15, 2008 Arrival Time: 9:00 am Permit #: N/A Weather: 45 °, sunny Subject: Retaining Wall Construction I arrived on site as arranged with Reg Morris of Baker Construction to observe continued construction of the Lock - and -Load retaining wall at the site. I met with Reg on -site When I arrived on -site I observed that the majority of the wall was backfilled and compacted to a level of 8 blocks. The 9th row was being set and leveled during my visit. I evaluated the compacted backfill by driving a 3 /4 -inch diameter field pin 12 inches with a 4 -lb hammer. Resulting blow counts of indicated the backfill was being prepared in general accordance with the intent of our recommendations. According to Marcos with Centerstone, the backfill is being compacted with both the large, hand - operated vibratory plates and a small smooth drum roller. Based on our observations and testing, the retaining wall backfill is being prepared in general accordance with the intent of specifications and our recommendations. Marcos stated that the current row of blocks being set will be the top of the wall and will be backfilled approximately half way with sand, with the surface comprised of compacted crushed rock. We will return to the site Monday morning to evaluate the final lift of backfill for the wall. Ryan hite, MS, PE, GE Senior Project Engineer cc: Kathy Peters, Discount Tire Co., kpeters @discounttireco.com Dana Korns, Discount Tire Co., dkorns @discounttireco.com Steve Beiser, Discount Tire Co., Steve.Beiser @discounttireco.com Reg Morris, Baker Construction, rmorris @bakerconstruct.com Todd Harnetiaux, Baker Construction, toddh @bakerconstruct.com Mike Dennis, Bones Construction, mike @bonesco.com Craig Harris, AAI Engineering, craigh @aaieng.com This report presents opinions formed as a result of our observation of activities relating to geotechnical engineering services. We rely on the contractor to comply with the plans and specifications throughout the duration of the project irrespective of the presence of our representative. Our work does not include quality control, and contractors and subcontractors have no right to rely on our services and reports. Our work does not include supervision or direction of the contractor, the contractor's employees, or agents. Our firm is not responsible for site safety. I/ 1 1 12 7 Street, Oregon City, OR 97045 p 503.657.3487 f 503.722.9946 G lutions Incl SITE VISIT REPORT: Discount Tire - Tigard, Oregon americastire- 07- 0I-cros To: Dan Wainwright, Discount Tire Co., dwainwright @discounttireco.com Visit Date: February 18, 2008 Arrival Time: 1:30 pm Permit #: N/A Weather: 58 °, sunny Subject: Foundation Subgrade Preparation I arrived on site as arranged with Norm of Bones Construction. I met with Norm, Randy of Bones Construction, and Reg Morris of Baker Construction on -site When I arrived on -site I observed the continuous footing along gridline A had been excavated to approximately subgrade elevation from gridline 2 to gridline 8 (northeast building corner). The footings had been overexcavated approximately 4 inches to account for the addition of 4 inches of crushed rock in the base of the footing excavations. The subgrades consisted of silt containing variable amounts of clay and rubblized basalt fragments. Penetration resistance with a 3 /4 -inch diameter foundation probed indicated the subgrades were generally medium stiff to very stiff. Approximately 2 to 3 inches of was present in the low areas of the excavation. The crushed rock in the base of the footings can be compacted until well -keyed using hand - operated equipment. Based on our observations and testing, the aforementioned footing subgrades have been prepared in general accordance with the intent of our recommendations. We will return to the site tomorrow to observe additional footing excavations. Ryan hite, MS, PE, GE • Senior Project Engineer cc: Kathy Peters, Discount Tire Co., kpeters @discounttireco.com Dana Korns, Discount Tire Co., dkorns @discounttireco.com Steve Beiser, Discount Tire Co., Steve.Beiser @discounttireco.com Reg Morris, Baker Construction, rmorris @bakerconstruct.com Todd Harnetiaux, Baker Construction, toddh @bakerconstruct.com Mike Dennis, Bones Construction, mike @bonesco.com Craig Harris, AA! Engineering, craigh @aaieng.com This report presents opinions formed as a result of our observation of activities relating to geotechnical engineering services. We rely on the contractor to comply with the plans and specifications throughout the duration of the project irrespective of the presence of our representative. Our work does not include quality control, and contractors and subcontractors have no right to rely on our services and reports. Our work does not include supervision or direction of the contractor, the contractor's employees, or agents. Our firm is not responsible for site safety. I/ 1 1 12 7` Street, Oregon City, OR 97045 p 503.657.3487 f 503.722.9946 6 ex to solutions Incl SITE VISIT REPORT: Discount Tire - Tigard, Oregon americastire- 07- 01-cros To: Dan Wainwright, Discount Tire Co., dwainwright @discounttireco.com Visit Date: February 19, 2008 Arrival Time: 1:45 pm Permit #: N/A Weather: 50 °, sunny Subject: Off Site Storm and Sanitary Sewer Trench Backfill I arrived on site as arranged with Norm of Bones Construction. I met with Norm, Herb of Bones Construction, and Reg Morris of Baker Construction on -site When I arrived on -site I observed the continuous footing along gridline A was being formed and excavation of the remaining footings would begin tomorrow. Herb stated that compaction of the off -site storm and sanitary trench backfill had been completed. The depth of cover ranged from approximately 2.0 to 3.5 feet at the south end, 7.0 to 9.0 feet near the mid -point (north- south), and 6.0 to 7.0 for approximately the northern third. The east -west portion of both trenches was backfilled with crushed rock due to the relatively shallow depth of cover. The remainder was backfilled with screenings (medium angular sand) and topped with 6 to 12 inches of crushed rock. Due to the proximity of the pipes to one another a single, wider trench was excavated, with both pipes installed in that trench. The trench backfill was evaluated by driving a 3 /4 -inch diameter field pin 12 inches with a 4 -lb hammer. Testing was completed at the.surface of the trench where the depth of cover was less than 6 feet, with the addition of a 3 -ft deep test in areas where the trenches were deeper. Resulting blow counts indicated that, in general, the aforementioned trench backfill had been adequately prepared. Two areas were identified as having inadequate compaction: the section of trench below the stairs, approximately mid way along the trench north - south, and a section at the north end, where the backfill appeared "wetter ". These areas were identified to Herb on -site and relayed to Reg prior to leaving the site. Based on our observations and testing, with the exception of the two identified areas, the aforementioned trench backfill has been prepared in general accordance with the intent of our recommendations. We will return to the site tomorrow as scheduled. Ryan hjte, MS, PE, GE Senior Project Engineer cc: Kathy Peters, Discount Tire Co., kpeters @discounttireco.com Dana Korns, Discount Tire Co., dkorns @discounttireco.com Steve Beiser, Discount Tire Co., Steve.Beiser @discounttireco.com Reg Morris, Baker Construction, rmorris @bakerconstruct.com Todd Harnetiaux, Baker Construction, toddh @bakerconstruct.com Mike Dennis, Bones Construction, mike @bonesco.com Craig Harris, AAI Engineering, craigh @aaieng.com This report presents opinions formed as a result of our observation of activities relating to geotechnical engineering services. We rely on the contractor to comply with the plans and specifications throughout the duration of the project irrespective of the presence of our representative. Our work does not include quality control, and contractors and subcontractors have no right to rely on our services and reports. Our work does not include supervision or direction of the contractor, the contractor's employees, or agents. Our firm is not responsible for site safety. I 1 1 12 7 Street, Oregon City, OR 97045 p 503.657.3487 f 503.722.9946 G e S p o lut ions I nci SITE VISIT REPORT: Discount Tire - Tigard, Oregon americastire- 07- 0I-cros To: Dan Wainwright, Discount Tire Co., dwainwright @discounttireco.com Visit Date: February 25, 2008 Arrival Time: 9:00 am Permit #: N/A Weather: 50 ° , mostly cloudy Subject: Footing Subgrades I arrived on site as arranged with Reg Morris of Baker Construction to observe footing subgrades. I met with Randy and Herb of Bones Construction, and Reg on -site When I arrived on -site I observed that footings B I, C I, Line 8 from A to B.9, Line 7 from A to D, and the trash enclosure wall footing had been excavated to approximately subgrade elevation. Footing C I contained a thin layer of silt fill that did not get adequately amended and was soft based on probing. I recommended to Rand that the soft soil in the corner of the footing be removed. Randy agreed. A sand backfilled trench was observed crossing footing C I. We understand the pipe in this trench will be terminated outside the building. This will result in a trench under the footing with no pipe. The backfill in the trench was loose based on probing and should be recompacted prior to forming the footing. Herb agreed. Approximately 6 to 12 inches of water was present in the observed eastern footings. The water was being pumped out of the excavations during my visit. All water must be removed from the footing excavations prior to pouring. In general, the footing subgrades consisted of cement amended silt or stiff native silt containing clay that was very stiff to hard based on probing. Soft soil at the surface of the subgrade at the north end of line 7 should be removed prior to rocking. We will return to the site tomorrow as scheduled to observe the remainder of the footing subgrades. Ryan /kite, MS, PE, GE Senior Project Engineer cc: Kathy Peters, Discount Tire Co., kpeters @discounttireco.com Dana Korns, Discount Tire Co., dkorns @discounttireco.com Steve Beiser, Discount Tire Co., Steve.Beiser @discounttireco.com Reg Morris. Baker Construction. rmorris @bakerconstructcom Todd Harnetiaux, Baker Construction, toddh @bakerconstruct.com Mike Dennis, Bones Construction, mike @bonesco.com Craig Harris, AAI Engineering, craigh @aaieng.com Walter Barnett, City of Tigard, walter @tigard- or.gov This report presents opinions formed as a result of our observation of activities relating to geotechnical engineering services. We rely on the contractor to comply with the plans and specifications throughout the duration of the project irrespective of the presence of our representative. Our work does not include quality control, and contractors and subcontractors have no right to rely on our services and reports. Our work does not include supervision or direction of the contractor, the contractor's employees, or agents. Our firm is not responsible for site safety. I /I 1 1 12 7 Street, Oregon City, OR 97045 p 503.657.3487 f 503.722.9946 • Ge te c � h solutions I ncl SITE VISIT REPORT: Discount Tire - Tigard, Oregon americastire- 07- 0I-cros To: Dan Wainwright, Discount Tire Co., dwainwright @discounttireco.com Visit Date: February 26, 2008 Arrival Time: 9:00 am Permit #: N/A Weather: 50 °, partly sunny Subject: Footing Subgrades, Offsite Trench Backfill. I arrived on site as arranged with Reg Morris of Baker Construction to observe footing subgrades for the new building. I met with Reg on -site. Footing Subgrades When I arrived on -site I observed that footings all footings observed during yesterdays visit had been covered with approximately 4 inches of crushed rock that was well keyed. Footings C.5 -I.5, D -2.5, D -4, D -5 had all be excavated and covered with approximately 4 inches of well keyed crushed rock. According to Reg, the pipe that passed through footing C I had been cut back outside the new building and the trench backfill compacted. The trench backfill was dense based on penetration resistance with a field probe. In general, the footing subgrades consisted of cement amended silt or native silt that was medium stiff to stiff based on probing. Based on our observations, the all the footing subgrades have been prepared in general accordance with the intent of the specifications and our recommendations. Offsite Trench Backfill Herb indicated yesterday that the trench backfill that had not been suitably prepared would be recompacted. I re- evaluated the two areas identified during our 2.19.08 visit. I evaluated the backfill by driving a 3 /4 -inch diameter field pin 12 inches with a 4 -lb hammer. Resulting blow counts averaged greater than I I indicating the trench backfill had been adequately prepared. We will return to the site as requested. 4. Ryanx/hite, MS, PE, GE Senior Project Engineer cc: Kathy Peters, Discount Tire Co., kpeters @discounttireco.com Dana Korns, Discount Tire Co., dkorns @discounttireco.com Steve Beiser, Discount Tire Co., Steve.Beiser @discounttireco.com Reg Morris, Baker Construction, rmorris @bakerconstruct.com Todd Harnetiaux, Baker Construction, toddh @bakerconstruct.com Mike Dennis, Bones Construction, mike @bonesco.com Craig Harris, AAI Engineering, craigh @aaieng.com Walter Barnett, City of Tigard, walter @tigard- or.gov This report presents opinions formed as a result of our observation of activities relating to geotechnical engineering services. We rely on the contractor to comply with the plans and specifications throughout the duration of the project irrespective of the presence of our representative. Our work does not include quality control, and contractors and subcontractors have no right to rely on our services and reports. Our work does not include supervision or direction of the contractor, the contractor's employees, or agents. Our firm is not responsible for site safety. • I/I 1 1 12 7` Street, Oregon City, OR 97045 p 503.657.3487 f 503.722.9946 G s o cb s Incl SITE VISIT REPORT: Discount Tire - Tigard, Oregon americastire- 07- 0I-cros To: Dan Wainwright, Discount Tire Co., dwainwright @discounttireco.com Visit Date: March 5, 2008 Arrival Time: 10:50 am Permit #: N/A Weather: 50 °, partly sunny Subject: Sidewalk Subgrade Preparation. I arrived on site as arranged with Norm of Bones Construction to observe preparation of the sidewalk subgrades in the ODOT ROW fronting Highway 99. I met with Norm and Randy of Bones Construction and Reg Morris of Baker Construction. The existing sidewalk had been demolished since our last visit. The exposed soils were consistent with those documented in our previous site visit report: silt with variable amounts of crushed rock, asphalt, and occasional boulders. On -site silt fill containing variable amounts of rock had been spread over the back (southern) portion of the sidewalk subgrade over approximately the western half of the sidewalk, creating a triangular (wedge) fill that was approximately 6 to 8 inches thick. The silt was visibly wet of optimum moisture with penetration from the small, single drum, pad -foot roller on the order of 4 to 5 inches deep. I recommended to norm that due to the current "wet conditions" silt soils are not suitable for use as structural fill. The silt soild could be amended with cement or replaced with clean granular fill such as sand or gravel. Norm proposed using the base rock that had been removed from the adjoining parking lot during demolition for installation of off -site utilities. The proposed material appeared to contain approximately 6 percent fines and was generally well - graded, 3 /4 -inch minus crushed rock. Based on our observations, the observed material is suitable for use fill as proposed. Norm indicated that the on -site silt fill would be removed later today and replaced. I relayed my observations to Reg prior to leaving the site. We will return to the site as contacted. Rya kite, MS, PE, GE Senior Project Engineer cc: Kathy Peters, Discount Tire Co., kpeters @discounttireco.com Dana Korns, Discount Tire Co., dkorns @discounttireco.com Steve Beiser, Discount Tire Co., Steve.Beiser @discounttireco.com Reg Morris, Baker Construction, rmorris @bakerconstruct.com Todd Harnetiaux, Baker Construction, toddh @bakerconstruct.com Mike Dennis, Bones Construction, mike @bonesco.com Craig Harris, AAI Engineering, craigh @aaieng.com This report presents opinions formed as a result of our observation of activities relating to geotechnical engineering services. We rely on the contractor to comply with the plans and specifications throughout the duration of the project irrespective of the presence of our representative. Our work does not include quality control, and contractors and subcontractors have no right to rely on our services and reports. Our work does not include supervision or direction of the contractor. the contractor's employees, or agents. Our firm is not responsible for site safety. I /I 1 1 12 7`' Street, Oregon City, OR 97045 p 503.657.3487 f 503.722.9946 e_p to I ncl SITE VISIT REPORT: Discount Tire - Tigard, Oregon americastire- 07- 01-cros To: Dan Wainwright, Discount Tire Co., dwainwright @discounttireco.com Visit Date: March 3, 2008 Arrival Time: 2:40 pm Permit #: N/A Weather: 45 °, partly sunny Subject: Footing Subgrades, Offsite Trench Backfill. I arrived on site as arranged with Norm of Bones Construction to observe stripping for the sidewalk in the ODOT ROW fronting Highway 99. Norm was not on -site during my visit. An approximate 10 ft wide area had been stripped for the entire width of the project site. The stripped area extended generally south of the existing sidewalk which we understand will be demolished, tomorrow. According to Norm, the new sidewalk will be underlain by a minimum of 6 inches of compacted crushed rock. The exposed subgrade consisted of silt, angular gravel, asphalt rubble, and boulders. In general, the topsoil and thick root zone had been removed. Thin zones of grass roots and /or topsoil were present in a few localized areas. Native soil backfill, used to fill the water line trench supplying the new fire hydrant near the intersection was soft to depths of greater than 2 feet based on penetration resistance with a field probe. Loose, soft, and saturated soil, localized areas of fine roots and topsoil, should be removed from the subgrade prior to placing the rock. If the aforementioned trench backfill will be under the sidewalk, the backfill should be removed and replaced with clean, granular structural fill. In general, provided the localized areas described above are prepared as recommended, the sidewalk subgrade within the ODOT ROW will have been prepared in general accordance with the intent of our recommendations. We will return to the site as contacted. Rya kite, MS, PE, GE Senior Project Engineer cc: Kathy Peters, Discount Tire Co., kpeters@discounttireco.com Dana Korns, Discount Tire Co., dkorns @discounttireco.com Steve Beiser, Discount Tire Co., Steve.Beiser @discounttireco.com Reg Morris, Baker Construction, rmorris@bakerconstruct.com Todd Harnetiaux, Baker Construction, toddh@bakerconstruct.com Mike Dennis, Bones Construction, mike @bonesco.com Craig Harris, AAI Engineering, craigh @aaieng.com Walter Barnett, City of Tigard, walter@tigard- or.gov This report presents opinions formed as a result of our observation of activities relating to geotechnical engineering services. We rely on the contractor to comply with the plans and specifications throughout the duration of the project irrespective of the presence of our representative. Our work does not include quality control, and contractors and subcontractors have no right to rely on our services and reports. Our work does not include supervision or direction of the contractor, the contractor's employees, or agents. Our firm is not responsible for site safety. I/ 1 1 12 7 Street, Oregon City, OR 97045 p 503.657.3487 f 503.722.9946 • Ge tech� solutions 1 ncl SITE VISIT REPORT: Discount Tire - Tigard, Oregon americastire- 07- 0I-cros To: Dan Wainwright, Discount Tire Co., dwainwright @discounttireco.com Visit Date: March 8, 2008 Arrival Time: 10:10 am Permit #: N/A Weather: 50 °, showers Subject: Sidewalk Base Rock Preparation. I arrived on site as requested by Reg Morris to observe preparation of the sidewalk base rock in the ODOT ROW fronting Highway 99. Nobody was on -site during my visit. When I arrived, I observed that that crushed rock had been spread and compacted over the sidewalk subgrade (excluding approximately I foot behind the curb where the temporary fence was anchored). The rock was clean, • angular, ' /cinch minus. In general the rock was approximately 4 to 6 inches thick. Crushed rock fill was present along the back of the sidewalk alignment in a few locations and was generally less than 12 inches thick. The rock appeared to have been compacted with a small smooth drum roller where the rock section was thicker, and a vibratory plate where the rock section was thinner. I evaluated the base rock using a ' /cinch diameter probe. Resulting penetration indicated the crushed rock was generally dense to very dense and had been suitable prepared. • Based on our observations, the base rock for the aforementioned sidewalk has been prepared in general accordance with the intent of our recommendations. We will return to the site as contacted. • A Ryanite, MS, PE, GE Senior Project Engineer cc: Kathy Peters, Discount Tire Co., kpeters @discounttireco.com Dana Korns, Discount Tire Co., dkorns @discounttireco.com Steve Beiser, Discount Tire Co., Steve.Beiser @discounttireco.com Reg Morris, Baker Construction, rmorris @bakerconstruct.com Todd Harnetiaux, Baker Construction, toddh @bakerconstruct.com Mike Dennis, Bones Construction, mike @bonesco.com Craig Harris, AAI Engineering, craigh @aaieng.com This report presents opinions formed as a result of our observation of activities relating to geotechnical engineering services. We rely on the contractor to comply with the plans and specifications throughout the duration of the project irrespective of the presence of our representative. Our work does not include quality control, and contractors and subcontractors have no right to rely on our services and reports. Our work does not include supervision or direction of the contractor, the contractor's employees, or agents. Our firm is not responsible for site safety. I/I 1 1 12 7th Street, Oregon City, OR 97045 p 503.657.3487 f 503.722.9946 • Solutions Incl SITE VISIT REPORT: Discount Tire - Tigard, Oregon americastire- 07- 01-cros To: Dan Wainwright, Discount Tire Co., dwainwright @discounttireco.com Visit Date: March I I, 2008 Arrival Time: 9:55 am Permit #: N/A Weather: 45 °, showers Subject: Sidewalk Subgrade - Old Trench Backfill. I arrived on site as arranged with Brad of Bones Construction (Bones) to re- evaluate the sidewalk subgrade for the sidewalk base in the ODOT ROW fronting Highway 99. I met with Norm and Randy of Bones and Reg Morris of Baker Construction on -site. The purpose of this visit was to evaluate the depth and extent of old utility trench backfill that crosses under the planned new sidewalk. The trench backfill appears to be associated with a waterline that crosses the northeastern corner of the site. Due to the trenches location in the formerly grass covered ROW, it appears it was backfilled with on -site silt with variable amounts of sand and gravel, prior to construction of the Americas Tire facility. The backfill is soft to depths of 18 to 24 inches, which we understand is likely the full depth of the trench. According to Norm a large portion of that area of the sidewalk subgrade will be disturbed as.a result of lower the gas line the crosses the same area. Norm stated that the soft backfill could be removed and replaced with clean, granular fill in conjunction with the gas line work. I relayed my observations to Reg prior to leaving the site. We will return to the site as contacted. X.J .•-" Ryart Qhite, MS, PE, GE Senior Project Engineer • cc: Kathy Peters, Discount Tire Co., kpeters @discounttireco.com Dana Korns, Discount Tire Co., dkorns @discounttireco.com Steve Beiser, Discount Tire Co., Steve.Beiser@discounttireco.com Reg Morris, Baker Construction, rmorris @bakerconstruct.com Todd Harnetiaux, Baker Construction, toddh @bakerconstruct.com Mike Dennis, Bones Construction, mike@bonesco.com Craig Harris, AAI Engineering, craigh@aaieng.com This report presents opinions formed as a result of our observation of activities relating to geotechnical engineering services. We rely on the contractor to comply with the plans and specifications throughout the duration of the project irrespective of the presence of our representative. Our work does not include quality control, and contractors and subcontractors have no right to rely on our.services and reports. Our work does not include supervision or direction of the contractor, the contractor's employees, or agents. Our firm is not responsible for site safety. I /1 1 1 12 7 Street, Oregon City, OR 97045 p 503.657.3487 f 503.722.9946 • Ge soiutions I ncl SITE VISIT REPORT: Discount Tire - Tigard, Oregon americastire- 07- 0I-cros To: Dan Wainwright, Discount Tire Co., dwainwright @discounttireco.com Visit Date: April 8, 2008 Arrival Time: 2:10 pm Permit #: N/A Weather: 50 °, occasional showers Subject: Sidewalk Subgrade - Old Trench Backfill. I arrived on site as arranged with Norm of Bones Construction (Bones) to observe installation of the drain and associated rock chimney along the northern embedded building wall. I met with Norm and Reg Morris of Baker Construction on -site. When I arrived I observed that the drain had been installed starting at the northwestern building corner and installed along the north side of the building to within approximately 30 feet of the northeastern building corner. A 6 -inch diameter perf pipe was being surrounded by angular drain rock and enclosed by a thick, non -woven geotextile fabric. The chimney drain was being brought to within approximately I foot of the adjacent ground surface, with the rock fully enclosed /covered. Based on our observations, the drain is being constructed in general accordance with our recommendations. We will return to the site as contacted. 4. RyarvViihite, MS, PE, GE Senior Project Engineer cc: Kathy Peters, Discount Tire Co., kpeters @discounttireco.com Dana Korns, Discount Tire Co., dkorns @discounttireco.com Steve Beiser, Discount Tire Co., Steve.Beiser @discounttireco.com Reg Morris, Baker Construction, rmorris @bakerconstruct.com Todd Harnetiaux, Baker Construction, toddh @bakerconstruct.com Mike Dennis, Bones Construction, mike @bonesco.com Craig Harris, AAI Engineering, craigh @aaieng.com This report presents opinions formed as a result of our observation of activities relating to geotechnical engineering services. We rely on the contractor to comply with the plans and specifications throughout the duration of the project irrespective of the presence of our representative. Our work does not include quality control, and contractors and subcontractors have no right to rely on our services and reports. Our work does not include supervision or direction of the contractor. the contractor's employees, or agents. Our firm is not responsible for site safety. I/ 1 1 12 7` Street, Oregon City, OR 97045 p 503.657.3487 f 503.722.9946 • G yI1 ec ions Inc' SITE VISIT REPORT: Discount Tire - Tigard, Oregon americastire- 07- 0I-cros To: Dan Wainwright, Discount Tire Co., dwainwright @discounttireco.com Visit Date: May 9, 2008 Arrival Time: 3:00 pm Permit #: N/A Weather: 50 °, partly sunny Subject: Observe Slab Rock and Thickened Edge Footings. I arrived on site as arranged with Norm of Bones Construction (Bones) to observe preparation of the slab rock and preparation of the thickened edge footing subgrades. Slab Rock When I arrived I observed that the slab rock had been compacted and was generally dense based on probing. The " room" at the western end of the building had several shallow trench excavations opened with the silt/rock excavation spoils stockpiled directly on the slab rock. The surface of the slab rock in the main area and the eastern room was generally dense of loose at the surface as a result of recent foot traffic and operation of the hydraulic lift. Prior to pouring the slab, the loose surficial slab rock should be recompacted. Areas of slab rock contaminated with silt, in the west and main rooms< must be replaced with clean crushed rock and compacted as structural fill prior to pouring the slab. Thickened Edge Footing Subgrades The thickened edge footing subgrades around the western perimeter and along the southern side of the building were composed of silt or cement amended structural fill. Water was present in the footing excavations at the west end of the building. A few inches of crushed rock had been placed in the base of the footing excavations. In general, where silt was present the subgrades were medium stiff to stiff. Where cement amended silt was present the subgrades were hard. Water should be removed and the crushed rock in the base of the footing excavation should be recompacted until "well- keyed" prior to forming/pouring the thickened edge footings. Conclusions Based on our observations, provided the identified areas are repaired as recommended, the slab rock and thickened . edge footing subgrades will have been prepared in general accordance with the intent of our recommendations. We will return to the site as contacted. Rya kite, MS, PE, GE Senior Project Engineer cc: Kathy Peters, Discount Tire Co., kpeters @discounttireco.com Dana Korns, Discount Tire Co., dkorns @discounttireco.com Steve Beiser, Discount Tire Co., Steve.Beiser @discounttireco.com Reg Morris, Baker Construction, rmorris @bakerconstruct.com Todd Harnetiaux, Baker Construction, toddh @bakerconstruct.com Mike Dennis, Bones Construction, mike @bonesco.com Craig Harris, AAI Engineering, craigh @aaieng.com This report presents opinions formed as a result of our observation of activities relating to geotechnical engineering services. We rely on the contractor to comply with the plans and specifications throughout the duration of the project irrespective of the presence of our representative. Our work does not include. quality control, and contractors and subcontractors have no right to rely on our services and reports. Our work does not include supervision or direction of the contractor, the contractor's employees, or agents. Our firm is not responsible for site safety. I/I 1 1 12 7 t ' Street, Oregon City, OR 97045 p 503.657.3487 f 503.722.9946 Ge sol u tions I ncl SITE VISIT REPORT: Discount Tire - Tigard, Oregon americastire- 07- 01-cros To: Dan Wainwright, Discount Tire Co., dwainwright @discounttireco.com Visit Date: May 19, 2008 Arrival Time: 3:00 pm Permit #: N/A Weather: 85 °, sunny Subject: Observe East Retaining Wall Footing Subgrade. I arrived on site as requested by Norm of Bones Construction (Bones) to observe preparation of footing subgrade for the eastern retaining wall. I met with Norm and Reg Morris of Baker Construction on -site. When I arrived I observed that the retaining wall footing had been excavated to approximately subgrade elevation and covered with a few inches of loose crushed rock. The subgrade consisted of silt that was medium stiff based on penetration resistance with a field probe. Norm stated that a 12 -inch zone of drain rock was planned behind the wall and asked about a drain pipe behind the wall. I stated that a drain pipe should be included. Norm stated that it could be tied into the drain pipe from the existing retaining wall. The new retaining wall footing will be formed on top of the existing retaining wall footing at the west end of the new wall and span the existing drain pipe (located behind the existing retaining wall footing) which is covered with 6 inches of crushed rock. Following connection of the drain pipe, the rock backfill above the pipe and covering the retaining wall footing subgrade should be compacted with hand - operated equipment until well keyed. Norm asked about what could be used for wall backfill. Given the proximity of the entrance drive behind the wall, I recommended the wall be backfilled with clean, crushed rock structural fill. I talked to Reg about this on -site and he confirmed that the wall would be backfilled with crushed rock. We will return to the site tomorrow as requested by Norm to observe excavation for the I0 -ft deep oil /water separator at the east end of the buiding. Ryan hire, MS, PE, GE Senior Project Engineer cc: Kathy Peters, Discount Tire Co., kpeters @discounttireco.com Dana Korns, Discount Tire Co., dkorns @discounttireco.com Steve Beiser, Discount Tire Co., Steve.Beiser @discounttireco.com Reg Morris, Baker Construction, rmorris @bakerconstructcom Todd Harnetiaux, Baker Construction, toddh @bakerconstruct.com Mike Dennis, Bones Construction, mike @bonesco.com Craig Harris, AAI Engineering, craigh @aaieng.com This report presents opinions formed as a result of our observation of activities relating to geotechnical engineering services. We rely on the contractor to comply with the plans and specifications throughout the duration of the project irrespective of the presence of our representative. Our work does not include quality control, and contractors and subcontractors have no right to rely on our services and reports. Our work does not include supervision or direction of the contractor, the contractor's employees, or agents. Our firm is not responsible for site safety. I/I 1 1 12 T Street, Oregon City, OR 97045 p 503.657.3487 f 503.722.9946 • G Solutions Incl SITE VISIT REPORT: Discount Tire - Tigard, Oregon americastire- 07- 0I-cros To: Dan Wainwright, Discount Tire Co., dwainwright @discounttireco.com Visit Date: May 22, 2008 Arrival Time: 9:00 am Permit #: N/A Weather: 50 °, cloudy Subject: Observe Oil/Water Separator Excavation Subgrade. I arrived on site as requested by Norm of Bones Construction (Bones) to observe the base of the excavation for the oil /water separator at the southeast corner of the new building. I met with Norm, Randy of Bones, and Reg Morris of Baker Construction on -site. When I arrived, the majority of the excavation had been completed. The exposed soil at the base of the excavation consisted of very stiff to hard silt/clay. The overlying soils consisted of silt and clay with variable amounts of basalt rubble, with one small boulder (2' x 2') encountered in the top 5 feet. The excavation was approximately 10 feet deep. Slow seepage was observed at a depth of approximately 8 to 9 feet below the surrounding ground surface. According to Randy, 6 to 12 inches of crushed rock, tamped until well- keyed, would be placed in the base of .the excavation. Clean granular fill, such as sand or crushed rock, will be used as backfill, compact in lifts around the perimeter of the oil /water separator. Based on our observations, the base of the excavation for the oil -water separator is suitable for the support of the planned structure. We will return to the site as contacted. Rya hite, MS, PE, GE Senior Project Engineer cc: Kathy Peters, Discount Tire Co., kpeters @discounttireco.com Dana Korns, Discount Tire Co., dkorns @discounttireco.com Steve Beiser, Discount Tire Co., Steve.Beiser @discounttireco.com Reg Morris, Baker Construction, rmorris @bakerconstruct.com Todd Harnetiaux, Baker Construction, toddh @bakerconstruct.com Mike Dennis, Bones Construction, mike @bonesco.com Craig Harris, AAI Engineering, craigh@aaieng.com • This report presents opinions formed as a result of our observation of activities relating to geotechnical engineering services. We rely on the contractor to comply with the plans and specifications throughout the duration of the project irrespective of the presence of our representative. Our work does not include quality control, and contractors and subcontractors have no right to rely on our services and reports. Our work does not include supervision or direction of the contractor, the contractor's employees, or agents. Our firm is not responsible for site safety. I/ 1 1 12 7 Street, Oregon City, OR 97045 p 503.657.3487 f 503.722.9946 • G solutions I ncl SITE VISIT REPORT: Discount Tire - Tigard, Oregon americastire- 07- 0I-cros To: Dan Wainwright, Discount Tire Co., dwainwright @discounttireco.com Visit Date: May 22, 2008 Arrival Time: 9:00 am Permit #: N/A Weather: 50 °, cloudy Subject: Observe Oil/Water Separator Excavation Subgrade. I arrived on site as requested by Norm of Bones Construction (Bones) to observe the base of the excavation for the oil /water separator at the southeast corner of the new building. I met with Norm, Randy of Bones, and Reg Morris of Baker Construction on -site. When I arrived, the majority of the excavation had been completed. The exposed soil at the base of the excavation consisted of very stiff to hard silt/clay. The overlying soils consisted of silt and clay with variable amounts of basalt rubble, with one small boulder (2' x 2') encountered in the top 5 feet. The excavation was approximately 10 feet deep. Slow seepage was observed at a depth, of approximately 8 to 9 feet below the surrounding ground surface. According to Randy, 6 to 12 inches of crushed rock, tamped until well- keyed, would be placed in the base of the excavation. Clean granular fill, such as sand or crushed rock, will be used as backfill, compact in lifts around the perimeter of the oil /water separator. Based on our observations, the base of the excavation for the oil -water separator is suitable for the support of the planned structure. We will return to the site as contacted. Rya hite, MS, PE, GE Senior Project Engineer cc: Kathy Peters, Discount Tire Co., kpeters @discounttireco.com Dana Korns, Discount Tire Co., dkorns@discounttireco.com Steve Beiser, Discount Tire Co., Steve.Beiser @discounttireco.com Reg Morris, Baker Construction, rmorris @bakerconstruct.com Todd Harnetiaux, Baker Construction, toddh @bakerconstruct.com Mike Dennis, Bones Construction, mike @bonesco.com Craig Harris, AA! Engineering, craigh @aaieng.com This report presents opinions formed as a result of our observation of activities relating to geotechnical engineering services. We rely on the contractor to comply with the plans and specifications throughout the duration of the project irrespective of the presence of our representative. Our work does not include quality control, and contractors and subcontractors have no right to rely on our services and reports. Our work does not include supervision or direction of the contractor, the contractor's employees, or agents. Our firm is not responsible for site safety. 1/1 1 1 12 7 Street, Oregon City, OR 97045 p 503.657.3487 f 503.722.9946 / /y(o,Z sid faetaKfZ*fi d 0 2e 0 7 co 1/5 RECEIVED AUG 2 3 2007 CITY OF TIGARD BUILDING DIVISION AMERICA'S TIRE .COMPANY STORM WATER_ REPORT & CALCULATIONS 99W & 68' Parkway Tigard, Oregon / '�� , p PR OA" r` (/ .58 t L �� Ca r 19 it . "Q" t � q�G N. t' • /0 / /l?� I EXPIRES: 6/30; 0'7 I October 18`", 2006 AAI PROJECT NUMBER: A06027.11 AAI ENGINEERING 4875 S.W. Griffith Drive Suite 300 Beaverton, Oregon 97005 PH 503.620.3030 FX 503.620.5539 EMAIL: crai ah(Eafghaninc.corn AMERICA'S TIRE COMPANY Project Overview The America's Best Tire building is located at 99W and 68` Parkway in Tigard, Oregon. The project will include a new building and a water quality / water quantity facility. The existing site consists of moderately sloped grassy terrain. The proposed building footprint is approximately 6,440SF and the proposed impervious paving is 14,145SF. The total proposed impervious area for the site is 20,585SF. The total site area is 34,170SF. The water quality and quantity facility required for this project will be designed according to the requirements outlined in the "Design and Construction Standards for Sanitary Sewer and Surface Water Management" by Clean Water Services, dated March 2004. The stormwater quality will be accomplished using an existing mechanical device. Stormwater Management builds the device specified for this project. The water quality treatment capacity for this device was accomplished using 0.36in over a 4 -hour period over the post - development impervious area. After the mechanical water quality device, the storm water from the lot will be detained in an underground storage system. The stonnwater will be released into an extension of the existing stormwater system in 68"' Parkway. The stormwater from the lot will be detained and released at pre - development levels for the 2 -year, 10 -year, and 25- year,.24- hour design storm events. Conveyance pipe sizing was performed using HydroCAD 8.00 to model the flow through the stormwater system. Conveyance flows were determined using the Santa Barbara Unit Hydrograph method for the 25 -year, 24 -hour design storm event. Conveyance pipe 0.463D S 2 sizing was performed using Manning's Equation (O = ), where D is pipe 77 diameter in feet, S is pipe slope in feet /feet, and n is the Manning's Coefficient and is • based on the pipe material. A value of 0.013 (concrete) was used for this project and is conservative if PVC piping is utilized for the project. Design storm rainfall distributions for the required design events were determined using 'the rainfall data in Section 1.2.c.1, Appendix A, in R &O 04 -09. All stormwater events were modeled as Type lA NCRS distributions. Please see the attached calculations showing that the on -site stormwater system meets the said requirement. AMERICA'S TIRE COMPANY Water Quality Design Water quality was calculated for this site using a total of 0.36 inches falling within a 4- hour period over 100% of the new impervious parking, building, sidewalk and drive lane area (20,585SF). The Contech Stormwater Solutions deep 1- Cartridge StormFilter Catch Basin treats a water quality flow (Q) up to 0.34cfs. The deep 1- cartridge catch basin has a built -in high flow bypass capable of passing up to a 1.80cfs flow. The deep SFCB has in internal permanent pool elevation 2' below the rim of the catch basin. This will cause some acceptable surcharging of the leading up to the SFCB, but will not cause any adverse effects, as the water level will still be below the invert elevations for the preceding catch basins building downspouts. The devices will have a built in high flow bypass for the difference in the water quality flows and the 25YR. flows, as tabulated below. Table 1 StormFilter CatchBasin Data Water Treatment peak Max. StormFilter Standard / Quality Capacity Flowrate Allowable Catch Basin Deep Flowrate Flowrate Flowrate (cfs) (cfs) (cfs) (cfs) CB2 Deep 0.017 0.034 0.11 1.80 CB4 Deep 0.026 0.034 0.17 1.80 • The Water Quality Volume is the expected stonmwater runoff volume from the water quality storm. Water Quality Volume (WQV) = 0.36iia. x Area 12in../ • /ft. _ 0.36in. x 20,585,ft. 12 in./ • /. f t. Water Quality Volume = 618 3 The Water Quality Flow is the expected design flow from the water quality storm. Water Quality Flow (WQF) = W01 _ 61 ft. 14,400 sec. 14,400 sec . Water Quality Flow (WQF) = 0.043 f 3 sec = 0.043cfs • AMERICA'S TIRE COMPANY Total Filter Calculations 449 gPm Number of Filters, Nn areal gPn� car! cart. Qcar� = 15 gPn� cart. 449 gp • N s / = 0.043c =1.28 15 gpn / /cart. A total of 2 Contech Stormwater Solutions StormFilters will be required. • • • • •