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MASON STREET INFRASTRUCTURE PROJECT - FDP230016 - SUBMITTAL DOCUMENTS - ROUND 1 - Geotechnical (Soils) Report
CTL|Thompson, Inc. Denver, Fort Collins, Colorado Springs, Glenwood Springs, Pueblo, Summit County – Colorado Cheyenne, Wyoming and Bozeman, Montana HIBDON/MASON 24/7 SHELTER SWC HIBDON COURT AND MASON STREET FORT COLLINS, COLORADO Prepared for: DENVER RESCUE MISSION C/O SHOPWORKS ARCHITECTURE 301 West 45th Avenue Denver, Colorado 80216 Attention: Chad Holtzinger Project No. FC10,520.000-125-R1 October 25, 2022 GEOTECHNICAL INVESTIGATION DRAFT Table of Contents DENVER RESCUE MISSION C/O SHOPWORKS ARCHITECTURE HIBDON/MASON 24/7 SHELTER CTL|T PROJECT NO. FC10,520.000-125-R1 SCOPE ...................................................................................................................................... 1 SUMMARY ................................................................................................................................ 1 SITE CONDITIONS ................................................................................................................... 2 PROPOSED CONSTRUCTION ................................................................................................. 3 INVESTIGATION ....................................................................................................................... 4 SUBSURFACE CONDITIONS ................................................................................................... 5 Natural Soil ............................................................................................................................. 5 Bedrock .................................................................................................................................. 5 Groundwater ........................................................................................................................... 5 GEOLOGIC HAZARDS .............................................................................................................. 6 Seismicity ............................................................................................................................... 7 SITE PREPARATION ................................................................................................................ 7 Sub-Excavation ...................................................................................................................... 7 Excavation .............................................................................................................................. 8 Fill and Backfill ....................................................................................................................... 9 Stabilization ............................................................................................................................ 9 Dewatering ............................................................................................................................10 Utilities ...................................................................................................................................10 FOUNDATIONS ........................................................................................................................11 FLOOR SYSTEMS ...................................................................................................................12 Structurally Supported Floors ................................................................................................14 Exterior Flatwork....................................................................................................................15 LATERAL LOADS .....................................................................................................................15 POND CONSTRUCTION ..........................................................................................................16 PAVEMENTS ............................................................................................................................17 SURFACE AND SUBSURFACE DRAINAGE ............................................................................19 CONCRETE ..............................................................................................................................21 CONSTRUCTION OBSERVATIONS ........................................................................................22 GEOTECHNICAL RISK ............................................................................................................23 LIMITATIONS ...........................................................................................................................24 DRAFT Table of Contents, Continued DENVER RESCUE MISSION C/O SHOPWORKS ARCHITECTURE HIBDON/MASON 24/7 SHELTER CTL|T PROJECT NO. FC10,520.000-125-R1 FIG. 1 – LOCATIONS OF EXPLORATORY BORINGS ON GOOGLE IMAGE FIG. 1B – LOCATION OF EXPLORATORY BORINGS ON PROPOSED DEVELOPMENT PLAN FIG. 2 – GROUNDWATER DEPTH AND ELEVATION APPENDIX A – SUMMARY LOGS OF EXPLORATORY BORINGS APPENDIX B – LABORATORY TEST RESULTS AND TABLE B-I APPENDIX C – FLEXIBLE AND RIGID PAVEMENT MATERIALS, CONSTRUCTION AND MAINTENANCE GUIDELINES DRAFT DENVER RESCUE MISSION C/O SHOPWORKS ARCHITECTURE 1 of 24 HIBDON/MASON 24/7 SHELTER CTL|T PROJECT NO. FC10,520.000-125-R1 SCOPE This report presents the results of our Geotechnical Investigation of the Hibdon/Mason 24/7 Shelter planned at the southwest corner of Hibdon Court and Ma- son Street in Ft. Collins, Colorado (Fig. 1). The purpose of our investigation was to eval- uate the subsurface conditions to provide geotechnical design and construction criteria for the project. The scope was described in the Service Agreement (DN 22-0318) dated July 6, 2022. Evaluation of the property for the possible presence of potentially hazard- ous materials (Environmental Site Assessment) was not included in our scope. This report was prepared from data developed during field exploration and recon- naissance, field and laboratory testing, engineering analysis of field and laboratory data, and our experience. It includes our opinions and recommendations for design criteria and construction details for foundations, floor systems, pavements, slabs-on-grade, lat- eral earth loads, and drainage precautions. Other types of construction may require re- vision of this report and the recommended design criteria. A summary of our conclu- sions and recommendations follows. Detailed design criteria are presented within the report. SUMMARY 1. Strata found in our exploratory borings consisted of about 6 to 11 feet of sandy clay over 10 to 14 feet of clayey, silty, gravelly sand and underlain by claystone bedrock. Claystone bedrock was encountered in four borings at depths of 18 to 22 feet. The clay is expansive. 2. Groundwater was encountered during drilling in all the borings at depths of 8 to 11 feet. When the test holes were checked after drilling on August 31, 2022, water was measured in five borings at depths of 8 to 9.5 feet or ap- proximate elevations 4970.5’ to 4973’. The remaining borings had caved at depths of 4.5 to 8 feet. Our experience suggests groundwater may be present near depths where caving occurred. Depending on grading plans, groundwater could be encountered during utility installation. Excavations that extend near groundwater levels may necessitate stabilization and temporary construction dewatering. Groundwater may fluctuate seasonally and rise or develop in response to development, precipitation, landscape irrigation and changes in land-use. DRAFT DENVER RESCUE MISSION C/O SHOPWORKS ARCHITECTURE 2 of 24 HIBDON/MASON 24/7 SHELTER CTL|T PROJECT NO. FC10,520.000-125-R1 3. The presence of expansive soil constitutes a geologic hazard. There is risk that slabs-on-grade and foundations may experience heave or settle- ment and damage. We believe the recommendations presented in this re- port will help to control risk of damage; they will not eliminate that risk. Slabs-on-grade and, in some instances, foundations may be damaged by soil movements. 4. We judge footing foundations can be used with calculated movement of about 1-inch or less provided they are constructed on well-compacted fill, as discussed in Sub-Excavation. Existing soils may be re-used as new fill provided debris, vegetation/organics, contaminated soils (if any) and other deleterious materials are removed. Design and construction criteria are pre- sented in the report. 5. The expansive clay presents risk of damaging movement to pavement systems. We recommend sub-excavating 3 feet below pavement areas to improve pavement performance. Parking areas will need a minimum of 6 inches of concrete or full depth asphalt, while access drives will need a minimum of 6 inches of concrete or 7 inches of full depth asphalt. Compo- site section alternatives are also presented in our report. Further design and criteria are presented in the report. 6. Surface drainage should be designed, constructed, and maintained to pro- vide rapid removal of runoff away from the buildings and off pavements and flatwork. Water should not be allowed to pond adjac ent to the build- ings or on pavements or flatwork. 7. The design and construction criteria for foundations and floor system alter- natives in this report were compiled with the expectation that all other rec- ommendations presented related to surface drainage, landscaping irriga- tion, backfill compaction, etc. will be incorporated into the project and that the owner or property manager will maintain the structures, use prudent irrigation practices and maintain surface drainage. It is critical that all rec- ommendations in this report are followed. SITE CONDITIONS The Hibdon/Mason 24/7 Shelter Site is located at the southwest corner of Hibdon Court and Mason Street in Ft. Collins, Colorado (Fig. 1 and Photo 1). The site is cur- rently vacant land adjoined by some commercial and manufacturing buildings to the south, single-family residential homes to the west, Mason Street to the east, and addi- tional vacant land with single-family residences to the north. According to the Larimer DRAFT DENVER RESCUE MISSION C/O SHOPWORKS ARCHITECTURE 3 of 24 HIBDON/MASON 24/7 SHELTER CTL|T PROJECT NO. FC10,520.000-125-R1 County Assessor, the site is part of a larger parcel. The proposed development is spread across two properties with parcel numbers “9702100918 and 9702100007” with a land acreage of 7.5 and 5.2 acres, respectively, according to the assessor. Mason Street was developed between 2014 and 2016, bisecting one of the parcels. Cache la Poudre River is less than ½-mile south of the site, Terry Lake and Long Pond are about ¾-mile northeast, Larimer and Weld Canal is ½-mile north, and Lindenmeier Lake is 1 ¼ miles east of the site. Dry Creek cuts through the site. Photo 1 – Google Earth© Aerial Site Photo, June 2021 PROPOSED CONSTRUCTION A conceptual site plan provided to CTL by Shopworks Architecture indicates de- velopment will consist of two structures with office and living/community space, paved parking, and possible plaza areas. We anticipate the structures will be three to four sto- ries with no below-grade areas. DRAFT DENVER RESCUE MISSION C/O SHOPWORKS ARCHITECTURE 4 of 24 HIBDON/MASON 24/7 SHELTER CTL|T PROJECT NO. FC10,520.000-125-R1 We understand this project is still in the conceptual phase. Construction and grading plans are not available at this time. The current site layout differs from the plan used to lay out our borings and we recommend additional drilling once site plans are more finalized to confirm recommendations presented in this report remain appropriate. INVESTIGATION We investigated subsurface conditions on August 18, 2022 by drilling and sam- pling nine exploratory borings at the approximate location shown on Fig. 1. Prior to drill- ing, we contacted the Utility Notification Center of Colorado and local sewer and water districts to identify locations of buried utilities. Boring location and elevations are approx- imate and were determined using a Leica GS18 GPS unit referencing the North Ameri- can Datum of 1983 (NAD83). The borings were drilled using 4-inch diameter, continu- ous-flight, solid-stem auger and truck-mounted CME-45 drill rig. We obtained samples at approximate 2 to 10-foot intervals using 2.5-inch diameter (O.D.) modified California barrel samplers driven by blows of an automatic 140-pound hammer falling 30 inches. Our field representative was present to observe drilling operations, log the strata en- countered, and obtain samples. Graphical log of the boring, including results of field penetration resistance tests and a portion of laboratory test data are presented in Ap- pendix A. Samples were returned to our laboratory where they were examined and testing was assigned. Laboratory tests included moisture content, dry density, particle-size analysis (percent silt and clay-sized particles passing the No. 200 sieve), gradation, At- terberg limits, swell-consolidation, standard Proctor, unconfined compressive strength, and water-soluble sulfate concentration. Swell-consolidation tests were performed by wetting the samples under approximate overburden pressures (the pressure exerted by overlying soils). Results of laboratory tests are presented in Appendix B and summa- rized in Table B-I. DRAFT DENVER RESCUE MISSION C/O SHOPWORKS ARCHITECTURE 5 of 24 HIBDON/MASON 24/7 SHELTER CTL|T PROJECT NO. FC10,520.000-125-R1 SUBSURFACE CONDITIONS Strata found in our exploratory borings consisted of about 6 to 11 feet of sandy clay over 10 to 14 feet of clayey, silty, gravelly sand underlain by claystone bedrock. Claystone bedrock was encountered in four borings at depths of 18 to 22 feet . Some of the pertinent engineering characteristics of the soil and bedrock are described in the fol- lowing paragraphs. Natural Soil Natural soils consisted of about 6 to 11 feet of sandy clay over 10 to 14 feet of clayey, silty, gravelly sand. The clay was medium stiff to very stiff and the sand was me- dium dense to very dense based on field penetration resistance tests. One clay sample did not swell, and three samples swelled 1.7 to 3.1 percent when wetted. The low to moderate swelling samples were encountered in the upper five feet of the borings. Four samples of sandy clay contained 73 to 91 percent fines (passing the No. 200 sieve) and one exhibited moderate plasticity with a liquid limit of 44. Four sand samples contained 3 to 7 percent fines. We judge the sand to be non-expansive. Bedrock Claystone bedrock was encountered at depths of 18 to 22 feet below existing grade or approximate elevations of 4958 to 4960 feet. The bedrock was very hard. Groundwater Groundwater was encountered during drilling in all the borings at depths of 8 to 11 feet. When the test holes were checked after drilling on August 31, 2022, water was measured in five borings at depths of 8 to 9.5 feet or approximate elevations 4970.5’ to 4973’. The remaining borings had caved at depths of 4.5 to 8 feet. Our experience sug- gests groundwater may be present near depths where caving occurred. Depending on DRAFT DENVER RESCUE MISSION C/O SHOPWORKS ARCHITECTURE 6 of 24 HIBDON/MASON 24/7 SHELTER CTL|T PROJECT NO. FC10,520.000-125-R1 grading plans, groundwater could be encountered during utility installation . Excavations that extend near groundwater levels may necessitate stabilization and temporary con- struction dewatering. Groundwater may fluctuate seasonally and rise or develop in re- sponse to development, precipitation, landscape irrigation and changes in land-use. GEOLOGIC HAZARDS Colorado is a challenging location to practice geotechnical engineering. The cli- mate is relatively dry and the near-surface soils are typically dry and comparatively stiff. These soils and related sedimentary bedrock formations react to c hanges in mois- ture conditions. Some of the soils swell as they increase in moisture and are referred to as expansive soils. Other soils can compress significantly upon wetting and are identi- fied as compressible soils. Much of the land available for develop ment east of the Front Range is underlain by expansive clay or claystone bedrock near the surface. The soils that exhibit compressible behavior are more likely west of the Continental Divide; how- ever, both types of soils occur throughout the state. Covering the ground with buildings, pavements, flatwork, etc., coupled with land- scape irrigation and changing drainage patterns, leads to an increase in subsurface moisture conditions. As a result, some soil movement due to heave or settlement is in- evitable. It is critical that precautions are taken to increase the chances that the founda- tions and slabs-on-grade will perform satisfactorily. Engineered design of grading, foun- dations, slabs-on-grade, and drainage can mitigate, but not eliminate, the effects of ex- pansive and compressible soils. After construction, property managers must assume re- sponsibility for maintaining the structure and use appropriate practices regarding drain- age and landscaping. Expansive soil is present at this site which constitutes a geologic hazard. There is risk that ground heave or settlement will damage slabs-on-grade and foundations. The risks can be mitigated, but not eliminated, by careful design, construction, and maintenance procedures. Expansive soil should be removed and replaced as discussed DRAFT DENVER RESCUE MISSION C/O SHOPWORKS ARCHITECTURE 7 of 24 HIBDON/MASON 24/7 SHELTER CTL|T PROJECT NO. FC10,520.000-125-R1 in Sub-Excavation. We believe the recommendations in this report will help reduce risk of foundation and/or slab damage; they will not eliminate that risk. Slabs-on-grade and, in some instances, foundations may be affected. Maintenance will be required to reduce risk. Seismicity The soil and bedrock are not expected to respond unusually to seismic activity. According to the 2021 International Building Code (IBC, Standard Penetration Re- sistance method), and based upon the results of our investigation, we judge the site classifies as Site Class C. SITE PREPARATION We believe there are no geotechnical constraints at this site that preclude devel- opment. The following discussion presents our opinions and recommendations for site development. Sub-Excavation Expansive clay was encountered in the upper 5 feet of our exploratory borings. Expansive soils present risk of damaging heave for foundations, slabs-on-grade, and pavements, and are not recommended in its current condition to support new construc- tion. We estimate total potential ground heave at the existing ground surface of 1.2 to 2.5 inches considering a 20-foot depth of wetting. Proposed grades and finished floor elevations are not known at this time. We believe sub-excavation to a depth of 5 feet below lowest foundation element will be necessary to mitigate expansive clay and allow use of shallow foundations and slab-on-grade floors for the structure. This recommen- dation should be re-evaluated once the site plan is finalized and additional drilling is per- formed. DRAFT DENVER RESCUE MISSION C/O SHOPWORKS ARCHITECTURE 8 of 24 HIBDON/MASON 24/7 SHELTER CTL|T PROJECT NO. FC10,520.000-125-R1 The bottom of sub-excavated areas should extend laterally at least 5 feet beyond the outside edge of footing. Sub-excavation should provide more uniform support condi- tions for footings and slab-on-grade floors and reduce potential differential movements. The extent and depth of removal should be surveyed. Special attention should be paid to compaction in the corners along the edges of excavation, as large equipment cannot easily access these areas. We recommend sub-excavation fill below buildings be mois- ture conditioned between 1 and 4 percent above optimum moisture content and com- pacted to at least 95 percent of standard Proctor maximum dry density. Our representa- tive should be present full time to observe and test compaction of sub -excavation fill during placement. Excavation We believe the soils penetrated by our exploratory bo rings can be excavated with typical heavy-duty equipment. We recommend the owner and the contractor become fa- miliar with applicable local, state and federal safety regulations, including the current Occupational Safety and Health Administration (OSHA) Exca vation and Trench Safety Standards. We anticipate the sand will classify as Type C soils, which require maximum side slope inclinations of 1½:1 (horizontal:vertical) for temporary excavations in dry con- ditions. The clay will likely classify as Type B soils, which require maximum slope incli- nations of 1:1 (horizontal:vertical) for temporary excavations in dry conditions, respec- tively. Excavations will require flatter slopes below groundwater and where seepage is present. The contractor’s “competent person” is required to identify the soils encoun- tered in the excavations and refer to OSHA standards to determine appropriate slopes. Stockpiles of soils and equipment should not be placed within a horizontal distance equal to one-half the excavation depth, from the edge of the excavation. A professional engineer should design excavations deeper than 20 feet, if any. DRAFT DENVER RESCUE MISSION C/O SHOPWORKS ARCHITECTURE 9 of 24 HIBDON/MASON 24/7 SHELTER CTL|T PROJECT NO. FC10,520.000-125-R1 Fill and Backfill The on-site soil is generally suitable for reuse as new fill, provided debris, organ- ics/vegetation and other deleterious materials are substantially removed. We expect the fill will require screening to properly remove debris. Soil particles larger than 3 inches in diameter should not be used for fill unless broken down. If imported fill is necessary for general site grading purposes, it should ideally consist of soil having a maximum parti- cle size of 2 inches, between 25 and 50 percent passing a No. 200 sieve, a liquid limit less than 30, and a plasticity index less than 15. Potential fill materials should be sub- mitted to our office for approval prior to importing to the site. Prior to fill placement, debris, organics/vegetation and deleterious materials should be substantially removed from areas to receive fill. The surface to be filled should be scarified to a depth of at least 8 inches, moisture conditioned and compacted to the criteria below. Subsequent fill should be placed in thin (8 inches or less) loose lifts, moisture conditioned to within 2 percent of optimum moisture content for sand and between 1 and 4 percent above optimum for clay, and compacted to at least 95 percent of standard Proctor maximum dry density (ASTM D 698). Our experience indicates fill and backfill can settle, even if properly compacted to the criteria provided above. Factors that influence the amount of settlement are depth of fill, soil type, degree of compaction, and time. The length of time for the compression to occur can be a few weeks to several years. The degree of compression of the recom- mended fill under its own weight will likely be 1 percent of the fill depth. Any improve- ments placed over backfill should be designed to accommodate movement. Stabilization Soft, wet soils in excavations should be removed or stabilized, if encountered. Soft excavation bottoms can likely be stabilized by crowding crushed rock into the soils until firm. Acceptable rock materials include, but are not limited to, No. 2 and No. 57 DRAFT DENVER RESCUE MISSION C/O SHOPWORKS ARCHITECTURE 10 of 24 HIBDON/MASON 24/7 SHELTER CTL|T PROJECT NO. FC10,520.000-125-R1 rock. Crushed rock on a layer of geosynthetic grid or woven fabric can also be used, which should reduce the amount of aggregate needed to stabilize the subgrade. Typi- cally, a biaxially woven fabric such as Mirafi 600x (or equal) or geogrid (su ch as Tensar BX1100 or equal) topped with 8 to 12 inches of 1 to 5 -inch crushed rock will provide a stable working surface. Dewatering Groundwater may be encountered in utility excavations. Temporary construction dewatering systems may be required to properly install deep utilities (if any) in areas of shallow groundwater. We believe dewatering for excavations which penetrate less than 3 to 5 below the groundwater surface may be accomplished using conventional sump and pump methods in utility trenches. We recommend the sump pits be at least 3 feet deeper than the bottom of the deepest excavation. Deeper excavations may require more elaborate dewatering (such as well points). The City of Fort Collins, Larimer County and/or the Colorado Department of Pub- lic Health and Environment may require dewatering permits. Our experience indicates periodic environmental testing is usually required with these permits, with reporting. Per- mitting requirements may also influence the construction schedule. Utilities Water, storm sewer and sanitary sewer lines are often constructed beneath slabs and pavements. Compaction of utility trench backfill can have a significant effect on the life and serviceability of floor slabs, pavements and exterior flatwork. We recommend utility trench backfill be placed and compacted as outlined above. Our experience indi- cates use of self-propelled compactors results in more reliable performance compared to fill compacted by an attachment on a backhoe or trackhoe. The upper portion of the trenches should be widened to allow the use of a self-propelled compactor. During con- DRAFT DENVER RESCUE MISSION C/O SHOPWORKS ARCHITECTURE 11 of 24 HIBDON/MASON 24/7 SHELTER CTL|T PROJECT NO. FC10,520.000-125-R1 struction, careful attention should be paid to compaction at curblines and around man- holes and water valves. The placement and compaction of utility trench backfill should be observed and tested by our firm. If soft or loose soils are encountered, removal and replacement with compacted fill or stabilization by crowding 1.5 to 3-inch nominal sized crushed rock or recycled con- crete until the base of excavation does not deform more than 1-inch when compactive effort is applied may be necessary. Special attention should be paid to backfill placed adjacent to manholes as we have observed conditions where settlement in excess of 1 percent has occurred after completion of construction. Flowable fill may be considered at critical utility crossings where it would be difficult to achieve adequate compaction. Fill should be moisture-conditioned and compacted to the specifications outlined in Fill and Backfill. The placement and compaction of utility trench backfill should be observed and tested by a representative of our firm during construction. FOUNDATIONS Our investigation indicates expansive clay is present at the anticipated founda- tion levels. The expansive clay should be mitigated as discussed in Sub-Excavation. Provided sub-excavation is performed as recommended, we believe footing foundations are appropriate for the structure. We estimate 1-inch or less of movement is possible af- ter sub-excavation. Design criteria for footing foundations developed from analysis of field and laboratory data and our experience are presented below. 1. Footings should be constructed on new, moisture conditioned and well- compacted fill as discussed in Sub-Excavation, or firm, natural sandy soils. Soils loosened during foundation excavation or in the forming pro- cess should be removed and replaced with new well-compacted fill prior to placing concrete. 2. Footings should be designed for a maximum allowable soil pressure of 2,500 psf with a minimum deadload of 800 psf. This may be increased by 1/3 to allow for short term loading DRAFT DENVER RESCUE MISSION C/O SHOPWORKS ARCHITECTURE 12 of 24 HIBDON/MASON 24/7 SHELTER CTL|T PROJECT NO. FC10,520.000-125-R1 3. A coefficient of friction can be used to resist lateral translation between concrete foundation elements and fill taken as 0.35. 4. Equivalent fluid densities for at-rest pressure and passive resistance pre- sented in the LATERAL LOADS portion of this report can be used in the design of spread footings. 5. Footings should have a minimum width of 16 inches. Foundations for iso- lated columns should have minimum dimensions of 20 inches by 20 inches. Larger sizes may be required depending upon the loads and struc- tural system used. 6. Foundation walls and grade beams should be well-reinforced. We recom- mend reinforcement sufficient to span an unsupported distance of at least 10 feet, where applicable. Reinforcement should be designed by the struc- tural engineer. 7. The completed foundation excavations should be observed b y a repre- sentative of our firm to confirm subsurface conditions are as anticipated. 8. Excessive wetting of foundation soils during and after construction can cause heave or softening and consolidation of foundation soils and result in footing movements. Proper surface drainage around the buildings is critical to control wetting. FLOOR SYSTEMS We anticipate the main floor levels of the buildings will have several uses, such as common areas, living space, lobbies, and mechanical/storage areas. Provided sub- excavation is performed, slab-on-grade floors can be used with anticipated potential movements on the order of 1-inch. If sensitive floor finishes will be used or movement cannot be tolerated, we recommend use of a structurally supported floor system . Slabs-on-grade are suitable, provided the potential movement and risk of distress are acceptable to the owner. Where conventional slabs-on-grade are used, we recom- mend the following design and construction criteria. These recommendations will not prevent movement. Rather, they tend to reduce damage if movement occurs. DRAFT DENVER RESCUE MISSION C/O SHOPWORKS ARCHITECTURE 13 of 24 HIBDON/MASON 24/7 SHELTER CTL|T PROJECT NO. FC10,520.000-125-R1 1. Slabs should be placed directly on the natural sand or properly moisture conditioned, well-compacted fill. The 2018 International Building Code (IBC) requires a vapor retarder be placed between the base course or subgrade soils and the concrete slab-on-grade floor. The merits of installa- tion of a vapor retarder below floor slabs depend on the sensitivity of floor coverings and building use to moisture. A properly installed vapor retarder (10 mil minimum) is more beneficial below concrete slab-on-grade floors where floor coverings, painted floor surfaces or products stored on the floor will be sensitive to moisture. The vapor retarder is most effective when concrete is placed directly on top of it, rather than placing a sand or gravel leveling course between the vapor retarder and the floor slab. The placement of concrete on the vapor retarder may increase the risk of shrinkage cracking and curling. Use of concrete with reduced shrinkage characteristics including minimized water content, maximized coarse ag- gregate content, and reasonably low slump will reduce the risk of shrink- age cracking and curling. Considerations and recommendations for the in- stallation of vapor retarders below concrete slabs are outlined in Section 5.2.3.2 of the 2015 report of American Concrete Institute (ACI) Comm ittee 302, “Guide to Concrete Floor and Slab Construction (ACI 302.1R-15).” 2. Slab-bearing partition walls should be designed and constructed to allow at least 2 inches of slab movement. If the slip joint is provided at the top of partitions, the connection between slab-supported partitions and founda- tion-supported walls should be detailed to allow differential movement. The property owner/manager should monitor partition voiding and other connections, and re-establish the gap when it closes to less than ½-inch. 3. Plumbing and utilities that pass through the slab should be isolated from the slabs and constructed with flexible couplings. Utilities, as well as elec- trical and mechanical equipment should be constructed with sufficient flex- ibility to allow for movement. 4. A modulus of subgrade reaction of 100 pci can be sued for the on-site soils, or similar new fill. This may be increased by 1/3 to allow for short term loading. 5. HVAC systems supported by the slabs (if any) should be provided with flexible connections capable of withstanding at least 2 inches of move- ment. 6. Exterior flatwork and sidewalks should be separated from the structure. These slabs should be detailed to function as independent units. Move- ment of these slabs should not be transmitted to the foundations. DRAFT DENVER RESCUE MISSION C/O SHOPWORKS ARCHITECTURE 14 of 24 HIBDON/MASON 24/7 SHELTER CTL|T PROJECT NO. FC10,520.000-125-R1 7. The American Concrete Institute (ACI) recommends frequent control joints be provided in slabs to reduce problems associated with shrinkage crack- ing and curling. To reduce curling, the concrete mix should have a high aggregate content and a low slump. If desired, a shrinkage compensating admixture could be added to the concrete to reduce the risk of shrinkage cracking. We can perform a mix design or assist the design team in select- ing a pre-existing mix. Structurally Supported Floors To our knowledge, there are no soil treatments combined with slab-on-grade floors that will result in the same reduction in risk of floor movement (relative to the risk inherent for a floor slab placed directly on the natural soils), as would be provided by a structural floor. If floor movement cannot be tolerated, then a structurally supported floor should be used. A structural floor is supported by the foundation system. Design and construction issues associated with structural floors include ventilation and lateral loads. Where structurally supported floors are installed over a crawl space, the required air space d e- pends on the materials used to construct the floor and the potential expansion of the un- derlying soils. Building codes require a clear space of 18 inches between exposed earth and untreated wood floor components. For non -organic floor systems, we recommend a minimum clear space of 8 inches. This minimum clear space should be maintained be- tween any point on the underside of the floor system (including beams and floor drain traps) and the soils. A slab-on-void system may also be considered. Void form should be chosen to break down quickly after the slab is placed. A sand or gravel leveling base below the void form should not be used. We recommend against the use of wax or plastic-coated boxes unless provisions are made to allow water vapor to penetrate the boxes, resulting in softening. DRAFT DENVER RESCUE MISSION C/O SHOPWORKS ARCHITECTURE 15 of 24 HIBDON/MASON 24/7 SHELTER CTL|T PROJECT NO. FC10,520.000-125-R1 Where structurally supported floors are used, utility connections including water, gas, air duct, and exhaust stack connections to floor supported appliances should be capable of absorbing some deflection of the floor. Plumbing that passes through the floor should ideally be hung from the underside of the structural floor and not lain on the bottom of the excavation. It is prudent to maintain the minimum clear space below all plumbing lines; this configuration may not be achievable for some parts of the installa- tion. Control of humidity in crawl spaces is important for indoor air quality and perfor- mance of wood floor systems. We believe the best current practices to control humidity involve the use of a vapor retarder or vapor barrier (10 mil) placed on the soils below accessible subfloor areas. The vapor retarder/barrier should be sealed at joints and at- tached to concrete foundation elements. Exterior Flatwork We recommend exterior flatwork and sidewalks around the building be isolated to reduce the risk of transferring slab movement to the structure. One alternative would be to construct the inner edges of the flatwork on haunches or steel angles bolted to the foundation walls and detailing the connections such that movement will cause less dis- tress to the building, rather than tying the slabs directly into the building foundations. Construction on haunches or steel angles and reinforcing the sidewalks and other exte- rior flatwork will reduce the potential for differential settlement and better allow them to span across foundation wall backfill. Frequent control joints should be provided to re- duce problems associated with shrinkage. Panels that are approximately s quare per- form better than rectangular areas. LATERAL LOADS Foundation walls and grade beams should be designed to resist lateral earth pressures. The amount of pressure on a wall is a function of the wall height, type of DRAFT DENVER RESCUE MISSION C/O SHOPWORKS ARCHITECTURE 16 of 24 HIBDON/MASON 24/7 SHELTER CTL|T PROJECT NO. FC10,520.000-125-R1 backfill, drainage conditions, slope of the backfill surface, and the allowable rotation of the wall. The building foundation walls will be essentially rigid and unable to rotate to mobilize the strength of the backfill soils. Therefore, they should be designed for an "at rest" earth pressure condition. For walls that are free to rotate slightly, an “active” earth pressure resistance can be used. A “passive” earth pressure resistance can be used to resist sliding and overturning. Passive resistance requires movement to generate re- sistance. We have tabulated equivalent fluid density values for on-site soil used as backfill in lateral earth pressure restraint design below. These values assume that backfill will be moisture-conditioned and compacted as described previously. The values do not in- clude allowances for surcharge loads such as adjacent foundations, sloping backfill, ve- hicle traffic, or hydrostatic pressure. LATERAL EQUIVALENT FLUID DENSITIES LOAD CONDITION CLAY Active Equivalent Fluid Density (pcf) 50 At Rest Equivalent Fluid Density (pcf) 65 Passive Equivalent Fluid Density (pcf)* 300* *Assumes backfill will not be removed. POND CONSTRUCTION We encountered 6 to 9 feet of sandy clay underlain by clean to slightly silty sand in the detention pond borings. Groundwater was encountered at depths of 8 to 11 feet (Elev. 4968.5 to 4973.5) at the time of drilling. During the delayed water checks the pond borings had caved at depths of 4.5 to 7.5 feet. Our experience suggests ground- DRAFT DENVER RESCUE MISSION C/O SHOPWORKS ARCHITECTURE 17 of 24 HIBDON/MASON 24/7 SHELTER CTL|T PROJECT NO. FC10,520.000-125-R1 water may be present near depths where caving occurred . The CDPHE will likely not al- low the mixing of storm water and groundwater. This should be taken into consideration when planning the location and depth of proposed detention ponds. Permeability of the on-site clay is considered to be negligible, and we estimate permeability rates on the order of 10 to 50 inches per hour for the on-site sand. We rec- ommend inlet/outlet pipes be bedded in a relatively impervious material such as clay or flow fill to reduce piping and soil erosion along the sides. Cutoff walls can be installed or a cradle may be constructed of concrete or flow fill that can support the pipe. Hand com- paction of embankment fill soils may be required around the pipes to reduce potential seepage between the outside of the pipes and fill. PAVEMENTS The project will include automobile parking and access drives. We assume all paved areas will be private. The performance of a pavement structure is dependent upon the characteristics of the subgrade soil, traffic loading and frequency, climatic con- ditions, drainage and pavement materials. As part of our investigation for this project, we drilled three borings in the proposed area of automobile parking and access drives based on the initial site plan. We considered Larimer County Urban Area Street Stand- ards (LCUASS, repealed and reenacted April 1, 2007) in combination with laboratory data and our experience to develop pavement design criteria. Subgrade soils generally classified as A-6 according to AASHTO criteria. Remolded Unconfined Compressive Strength testing was conducted on two composite samples of soils from our pavement borings. For our pavement design, we have tabu- lated a modulus of subgrade reaction of 14,561 psi considering lab test results. Samples obtained in our pavement borings swelled 1.8 to 6.6 percent. We rec- ommend sub-excavation to a depth of 3 to 5 feet below bottom of pavement section to DRAFT DENVER RESCUE MISSION C/O SHOPWORKS ARCHITECTURE 18 of 24 HIBDON/MASON 24/7 SHELTER CTL|T PROJECT NO. FC10,520.000-125-R1 improve pavement performance. Subgrade should be proof-rolled with a loaded, tan- dem-axle dump truck to disclose soft/loose areas. These areas should be reworked and compacted. Subgrade areas that pass proof-roll should be stable enough to pave. We are assuming flexible hot mix asphalt (HMA) pavement is planned for the parking lots. Rigid portland cement concrete (PCC) pavement should be considered for trash enclosure areas and where the pavement will be subjected to frequent turning of heavy vehicles. Pavement section alternatives are provided below. SUMMARY OF RECOMMENDED MINIMUM PAVEMENT ALTERNATIVES Hot Mix Asphalt (HMA) + Aggregate Base (ABC) Full Depth Asphalt Portland Cement Con- crete (PCC)* Parking Areas 4" HMA + 8" ABC 6” 6" PCC Access Drives 5" HMA + 6" ABC 7” 6"PCC Trash Enclosures - - 6" PCC Our experience indicates problems with asphalt pavements can occur where heavy trucks drive into loading and unloading zones and turn at low speeds. In areas of concentrated loading and turning movements by heavy trucks, such as at entrances and trash collection areas, we recommend a 6-inch or thicker Portland cement concrete pad be constructed at loading docks and dumpster locations, or other areas where trucks will stop or turn. The concrete pads should be of sufficient size to accommodate truck turning, trash pickup and delivery/loading areas. A section of 7 inches can be used if ex- tra durability is desired. The design of a pavement system is as much a function of paving materials as supporting characteristics of the subgrade. All soils that will support pavements should be scarified, moisture conditioned, and compacted prior to paving. The quality of each construction material is reflected by the strength coefficient used in the calculations. If the pavement system is constructed of inferior material, then the life and serviceability of the pavement will be substantially reduced. Materials and placement methods should conform to the requirements of the Larimer County Urban Area Street Standards. All DRAFT DENVER RESCUE MISSION C/O SHOPWORKS ARCHITECTURE 19 of 24 HIBDON/MASON 24/7 SHELTER CTL|T PROJECT NO. FC10,520.000-125-R1 materials planned for construction should be tested to confirm their compliance with pro- ject specifications. Control joints should separate concrete pavements into panels as recommended by ACI. No de-icing salts should be used on paving concrete for at least one year after placement. Routine maintenance, such as sealing and repair of cracks and overlays at 5 to 7-year intervals, are necessary to achieve long-term performance of an asphalt sys- tem. We recommend application of a rejuvenating sealant such as fog seal after the first year. Deferring maintenance usually results in accelerated deterioration of pavements leading to higher future maintenance costs. A primary cause of early pavement deterioration is water infiltration into the pave- ment system. The addition of moisture usually results in softening of the subgrade and eventual failure of the pavement. We recommend drainage be designed for rapid re- moval of surface runoff. Curb and gutter should be backfilled and the backfill compacted to reduce ponding adjacent to the pavements. Final grading of the subgrade should be carefully controlled so that design cross-slope is maintained and low spots in the sub- grade which could trap water are eliminated. Seals should be provided between curb and pavement and at all joints to reduce moisture infiltration. Landscaped areas and de- tention ponds in pavements should be avoided. Recommended material properties and construction criteria for pavements are provided in Appendix C. These criteria were developed from analysis of the field and la- boratory data and our experience. If the materials cannot meet these recommendations, then the pavement design should be re-evaluated based upon available materials. SURFACE AND SUBSURFACE DRAINAGE Water from irrigation frequently flows through relatively permeable backfill placed adjacent to buildings and collects on the surface of less permeable soils occurring at the DRAFT DENVER RESCUE MISSION C/O SHOPWORKS ARCHITECTURE 20 of 24 HIBDON/MASON 24/7 SHELTER CTL|T PROJECT NO. FC10,520.000-125-R1 bottom of excavations. This process can cause wet or moist below-grade conditions af- ter construction. There are no below-grade areas planned at this time with exception to the elevator/stairwell core pit, if planned. These areas would merit use of a drain. Alter- natively, they can be designed and constructed to be water tight. Buoyancy effects should be considered. Our experience indicates moist conditions can develop in crawl spaces (if con- structed), resulting in isolated instances of damp soils, musty smells, and, in rare cases, standing water. Crawl spaces should be well ventilated, depending on the use of a va- por retarder/barrier and the floor material selected. Performance of foundations, pavements and flatwork is influenced by the mois- ture conditions existing within the foundation or subgrade soils. The risk of wetting the foundation and floor subgrade soils can be reduced by carefully planned and main- tained surface grades and drainage. Excessive wetting before, during and/or after con- struction may cause movement of foundations and slabs-on-grade. We recommend the following precautions be observed during construction and maintained at all times after construction is completed. 1. Wetting or drying of open foundation, utility and earthwork excavations should be avoided. 2. Positive drainage should be provided away from the improvements. Paved surfaces should be sloped to drain away from the additions. A minimum slope of 1 percent is suggested. More slope is desirable. Concrete curbs and sidewalks may “dam” surface runoff and disrupt proper flow. Use of “chase” drains or weep holes at low points in the curb should be consid- ered to promote proper drainage. 3. Backfill around foundations should be moistened and compacted accord- ing to criteria presented in Fill and Backfill. Areas behind curb and gutter should be backfilled and well compacted to reduce ponding of surface wa- ter. Seals should be provided between the curb and pavement to reduce infiltration. 4. Landscaping should be carefully designed to minimize irrigation. Plants used close to foundation walls should be limited to those with low moisture DRAFT DENVER RESCUE MISSION C/O SHOPWORKS ARCHITECTURE 21 of 24 HIBDON/MASON 24/7 SHELTER CTL|T PROJECT NO. FC10,520.000-125-R1 requirements. Irrigation should be limited to the minimum amount suffi- cient to maintain vegetation. Application of more water will increase likeli- hood of slab and foundation movements and associated damage. Land- scaped areas should be adequately sloped to direct flow away from the improvements. Use of area drains can assist draining areas that cannot be provided with adequate slope. 5. Impervious plastic membranes should not be used to cover the ground surface immediately surrounding foundations. These membranes tend to trap moisture and prevent normal evaporation from occurring. Geotextile fabrics can be used to control weed growth and allow evaporation. 6. Roof drains should be directed away from the additions and discharge be- yond backfill zones or into appropriate storm sewer or detention area. Downspout extensions and splash blocks should be provided at all dis- charge points. Roof drains can also be connected to buried, solid pipe out - lets. Roof drains should not be directed below slab-on-grade floors. Roof drain outlets should be maintained. CONCRETE Concrete in contact with soil can be subject to sulfate attack. We measured wa- ter-soluble sulfate concentrations of 0.20 to 0.80 percent in three samples, with an aver- age of 0.55 percent. As indicated in our tests and ACI 318-19, the sulfate exposure class is Severe or S2. SULFATE EXPOSURE CLASSES PER ACI 318-19 Exposure Classes Water-Soluble Sulfate (SO4) in Soil A (%) Not Applicable S0 < 0.10 Moderate S1 0.10 to 0.20 Severe S2 0.20 to 2.00 Very Severe S3 > 2.00 A) Percent sulfate by mass in soil determined by ASTM C1580 For this level of sulfate concentration, ACI 318-19 Code Requirements indicates there are special cement type requirements for sulfate resistance as indicated in the ta- ble below. DRAFT DENVER RESCUE MISSION C/O SHOPWORKS ARCHITECTURE 22 of 24 HIBDON/MASON 24/7 SHELTER CTL|T PROJECT NO. FC10,520.000-125-R1 CONCRETE DESIGN REQUIREMENTS FOR SULFATE EXPOSURE PER ACI 318-19 Exposure Class Maximum Water/ Cement Ratio Minimum Compressive Strength (psi) Cementitious Material Types A Calcium Chloride Admixtures ASTM C150/ C150M ASTM C595/ C595M ASTM C1157/ C1157M S0 N/A 2500 No Type Restrictions No Type Restrictions No Type Restrictions No Restrictions S1 0.50 4000 IIB Type with (MS) Designation MS No Re- strictions S2 0.45 4500 V B Type with (HS) Designation HS Not Permitted S3 Option 1 0.45 4500 V + Pozzolan or Slag Cement C Type with (HS) Designation plus Pozzolan or Slag Cement C HS + Pozzolan or Slag Cement C Not Permitted S3 Option 2 0.4 5000 V D Type with (HS) Designation HS Not Permitted A) Alternate combinations of cementitious materials shall be permitted when tested for sulfate resistance meet- ing the criteria in section 26.4.2.2(c). B) Other available types of cement such as Type III or Type I are permitted in Exposure Classes S1 or S2 if the C3A contents are less than 8 or 5 percent, respectively. C) The amount of the specific source of pozzolan or slag to be used shall not be less than the amount that has been determined by service record to improve sulfate resistance when used in concrete containing Type V cement. Alternatively, the amount of the specific source of the pozzolan or slab to be used shall not be less than the amount tested in accordance with ASTM C1012 and meeting the criteria in section 26.4.2.2(c) of ACI 318. D) If Type V cement is used as the sole cementitious material, the optional sulfate resistance requirement of 0.040 percent maximum expansion in ASTM C150 shall be specified. Superficial damage may occur to the exposed surfaces of highly permeable con- crete, even though sulfate levels are relatively low. To control this risk and to resist freeze-thaw deterioration, the water-to-cementitious materials ratio should not exceed 0.50 for concrete in contact with soils that are likely to stay moist due to surface drain- age or high-water tables. Concrete should have a total air content of 6 percent ± 1.5 percent. We advocate damp-proofing of all foundation walls and grade beams in contact with the subsoils. CONSTRUCTION OBSERVATIONS This report has been prepared for the exclusive use of Shopworks Architecture and your design team for the purpose of providing geotechnical design and construction DRAFT DENVER RESCUE MISSION C/O SHOPWORKS ARCHITECTURE 23 of 24 HIBDON/MASON 24/7 SHELTER CTL|T PROJECT NO. FC10,520.000-125-R1 criteria for the proposed project. The information, conclusions, and recommendations presented herein are based upon consideration of many factors including, but not lim- ited to, the type of structures proposed, the geologic setting, and the subsurface condi- tions encountered. The conclusions and recommendations contained in the report are not valid for use by others. Standards of practice evolve in geotechnical engineering. The recommendations provided are appropriate for about three years. If the project is not constructed within about three years, we should be contacted to determine if we should update this report. We recommend that CTL | Thompson, Inc. provide construction observation ser- vices to allow us the opportunity to verify whether soil conditions are consistent with those found during this investigation. If others perform these observations, they must accept responsibility to judge whether the recommendations in this report remain appro- priate. GEOTECHNICAL RISK The concept of risk is an important aspect with any geotechnical evaluation pri- marily because the methods used to develop geotechnical recommendations do not comprise an exact science. We never have complete knowledge of subsurface condi- tions. Our analysis must be tempered with engineering judgment and experience. Therefore, the recommendations presented in any geotechnical evaluation should not be considered risk-free. Our recommendations represent our judgment of those measures that are necessary to increase the chances that the structures will perform satisfactorily. It is critical that all recommendations in this report are followed during con- struction. Owners or property managers must assume responsibility for maintaining the structures and use appropriate practices regarding drainage and landscaping. Improve- ments after construction should be completed in accordance with recommendations provided in this report and may require additional soil investigation and consultation. DRAFT DENVER RESCUE MISSION C/O SHOPWORKS ARCHITECTURE 24 of 24 HIBDON/MASON 24/7 SHELTER CTL|T PROJECT NO. FC10,520.000-125-R1 LIMITATIONS Our borings were spaced to obtain a reasonably accurate picture of subsurface conditions at this site. The boring is a representative of conditions encountered only at the location drilled. Subsurface variations not indicated by the boring are p ossible. We believe this investigation was conducted in a manner consistent with the level of care and skill ordinarily used by geotechnical engineers practicing under similar con- ditions. No warranty, express or implied, is made. If we can be of further service in dis- cussing the contents of this report, or in the analysis of the influence of the subsurface conditions on the design of the addition or any other aspect of the proposed construc- tion, please call. CTL | THOMPSON, INC. Abhinav Jakilati Staff Engineer Reviewed by: Erin Beach, P.E., P.G. Geotechnical Project Manager Via e-mail: chad@shopworksarc.com rieko@shopworksarc.com DRAFT HIBDON CTE. WILLOX LN.HICKORY ST.COLLEGE AVE.SITEMASON ST.| DRAFT HIBDON COURTFL=4978.11STM MHRIM=4979.03INV IN=4974.91 (NE)INV OUT=4974.83 (SE)12" RCP12" R C P STM MHRIM=4978.59INV IN=4976.04 (N)INV OUT=4976.03 (W)12" RCPSTM INLETGRT=4978.93INV IN=4976.23 (N)INV IN=4976.53 (W)INV OUT=4976.21 (S)215.7 LF 12" RCP @ 0.08%28.9 LF 12"RCP @ 5.47%GRT=4978.93INV OUT=4976.53 (S)38.6 LF 12"RCP @ 0.78%FL=4975.87FL=4975.1513.3 LFCULVERT @ 5.4%FL=4981.61FL=4980.1513.1 LF CULVERT @ 11.1%OTHER ENDOF LINE NOT FOUNDOTHER ENDOF LINE NOT FOUND'NO TRESPASSING"REFLECTIVEBARRICADE"STOP"SAN MHRIM=4979.91INV IN=4973.06 (N)INV IN=4973.01 (W)INV OUT=4972.91 (S)12" PVC12" PVCSAN MHRIM=4979.78INV IN=4974.83 (W)INV OUT=4974.78 (E)SAN MHRIM=4979.15INV IN=4974.43 (W)INV OUT=4974.35 (E)331.3 LF 6" PVC @ 0.40%70.6 LF 6" PVC @ 0.50%(R) WEST 986'(R) SOUTH262.8'(R) EAST 986'(R) NORTH 262.8'(R) WEST 300.00'28.9'19.0'(R) NORTH 60.00'(R) EAST 275.00'(R) SOUTH 161.80'PARCEL 2LOT 222,632 sq. ft.0.520 ac.PARCEL 3257,921 sq. ft.5.921 ac.PARCEL 3257,921 sq. ft.5.921 ac.GATEGATEGATEb1475 p94110' UTILITY EASEMENTBK 1572 PG 322BK 1572 PG 32120' UTILITY EASEMENTPER PLAT OF BREWSUB. FIRST FILINGUTILITY EASEMENTBK 1658 PG 746UTILITY EASEMENTBK 1658 PG 746ELECTRIC EASEMENTBK 1475 PG 941ELECTRIC EASEMENTBK 1475 PG 941RIALROAD R.O.W.AGREEMENTBK 813 PG 276' UTILITY EASEMENTPER PLAT OF BREWSUB. FIRST FILINGRIGHT OF WAYEASEMENTBK 929 PG 30RIGHT OF WAYBK 1743 PG 63224' ACCESS EASEMENTREC. NO. 20140038802FND #4 REBARNO CAPFND #4 REBARNO CAPFND #4 REBARNO CAP1 STORYBLOCK1STORYMETALSSELEC FESMVAULT ELEC VAULTELEC VAULT ELEC CABLEWVWVHYDh2oDCABLED VAULT ELEC CELEC ELEC ELEC S4980498149814981498149814981498049814980497749774978 4978497949814982498049764977497849794981498149804976497749784979498149814980497649764980498149804979 49794979497949794980497849784979497 9 49784978498049804981498149804980498149804982498049794981498249814978 497 9 498049804980HIBDON CTE. WILLOX LN.HICKORY ST.COLLEGE AVE.SITEMASON ST.| DRAFT HIBDON COURTFL=4978.11STM MHRIM=4979.03INV IN=4974.91 (NE)INV OUT=4974.83 (SE)12" RCP12" R C P STM MHRIM=4978.59INV IN=4976.04 (N)INV OUT=4976.03 (W)12" RCPSTM INLETGRT=4978.93INV IN=4976.23 (N)INV IN=4976.53 (W)INV OUT=4976.21 (S)215.7 LF 12" RCP @ 0.08%28.9 LF 12"RCP @ 5.47%GRT=4978.93INV OUT=4976.53 (S)38.6 LF 12"RCP @ 0.78%FL=4975.87FL=4975.1513.3 LFCULVERT @ 5.4%FL=4981.61FL=4980.1513.1 LF CULVERT @ 11.1%OTHER ENDOF LINE NOT FOUNDOTHER ENDOF LINE NOT FOUND'NO TRESPASSING"REFLECTIVEBARRICADE"STOP"SAN MHRIM=4979.91INV IN=4973.06 (N)INV IN=4973.01 (W)INV OUT=4972.91 (S)12" PVC12" PVCSAN MHRIM=4979.78INV IN=4974.83 (W)INV OUT=4974.78 (E)SAN MHRIM=4979.15INV IN=4974.43 (W)INV OUT=4974.35 (E)331.3 LF 6" PVC @ 0.40%70.6 LF 6" PVC @ 0.50%(R) WEST 986'(R) SOUTH262.8'(R) EAST 986'(R) NORTH 262.8'(R) WEST 300.00'28.9'19.0'(R) NORTH 60.00'(R) EAST 275.00'(R) SOUTH 161.80'PARCEL 2LOT 222,632 sq. ft.0.520 ac.PARCEL 3257,921 sq. ft.5.921 ac.PARCEL 3257,921 sq. ft.5.921 ac.GATEGATEGATEb1475 p94110' UTILITY EASEMENTBK 1572 PG 322BK 1572 PG 32120' UTILITY EASEMENTPER PLAT OF BREWSUB. FIRST FILINGUTILITY EASEMENTBK 1658 PG 746UTILITY EASEMENTBK 1658 PG 746ELECTRIC EASEMENTBK 1475 PG 941ELECTRIC EASEMENTBK 1475 PG 941RIALROAD R.O.W.AGREEMENTBK 813 PG 276' UTILITY EASEMENTPER PLAT OF BREWSUB. FIRST FILINGRIGHT OF WAYEASEMENTBK 929 PG 30RIGHT OF WAYBK 1743 PG 63224' ACCESS EASEMENTREC. NO. 20140038802FND #4 REBARNO CAPFND #4 REBARNO CAPFND #4 REBARNO CAP1 STORYBLOCK1STORYMETALSSELEC FESMVAULT ELEC VAULTELEC VAULT ELEC CABLEWVWVHYDh2oDCABLED VAULT ELEC CELEC ELEC ELEC S4980498149814981498149814981498049814980497749774978 4978497949814982498049764977497849794981498149804976497749784979498149814980497649764980498149804979 49794979497949794980497849784979497 9 49784978498049804981498149804980498149804982498049794981498249814978 497 9 498049804980| DRAFT DENVER RESCUE MISSION C/O SHOPWORKS ARCHITECTURE HIBDON/MASON 24/7 SHELTER CTL|T PROJECT NO. FC10,520.000-125-R1 APPENDIX A LABORATORY TEST RESULTS DRAFT ELEVATION - FEETSUMMARY LOGS OF EXPLORATORY BORINGSDENVER RESCUE MISSION C/O SHOPWORKS ARCHITECTURE FIG. A-1 4,940 4,945 4,950 4,955 4,960 4,965 4,970 4,975 4,980 4,985 4,940 4,945 4,950 4,955 4,960 4,965 4,970 4,975 4,980 4,985 ELEVATION - FEETWC=17.7DD=108SW=1.7 WC=25.6DD=96SW=0.0 TH-1 El. 4980.3 10/12 7/12 50/12 50/3 50/1 24/12 16/12 50/9 50/1 50/2 50/1 50/1 WC=16.1DD=113SW=3.1 WC=11.3-200=3 TH-2 El. 4980.9 18/12 36/12 50/9 50/2 50/1 WC=17.9DD=113SW=2.2 TH-3 El. 4980.3 HIBDON/MASON 24/7 SHELTER CTL|T PROJECT NO. FC10520-125-R1 DRAFT 4,940 4,945 4,950 4,955 4,960 4,965 4,970 4,975 4,980 4,985 4,940 4,945 4,950 4,955 4,960 4,965 4,970 4,975 4,980 4,985 ELEVATION - FEETELEVATION - FEETSUMMARY LOGS OF EXPLORATORY BORINGSDENVER RESCUE MISSION C/O SHOPWORKS ARCHITECTURE FIG. A-2 13/12 17/12 WC=6.3DD=96LL=25 PI=11-200=58 20/12 P-1 El. 4981.5 WC=15.0DD=112UC=6,863 WC=17.7DD=112SW=1.8SS=0.20 WC=12.8DD=102LL=37 PI=21-200=75 15/12 27/12 WC=11.8DD=111SW=6.6SS=0.80 P-2 El. 4980.3 WC=15.0DD=109UC=5,544 7/12 15/12 32/12 P-3 El. 4979.9 WC=11.0DD=106LL=30 PI=16-200=81 WC=16.5DD=109SW=2.1SS=0.64 19/12 HIBDON/MASON 24/7 SHELTER CTL|T PROJECT NO. FC10520-125-R1 DRAFT INDICATES DEPTH WHERE HOLE CAVED. 1. WATER LEVEL MEASURED AFTER DRILLING ON AUGUST 31, 2022. 3. 2. DENVER RESCUE MISSION C/O SHOPWORKS ARCHITECTURE FIG. A-3 4,940 4,945 4,950 4,955 4,960 4,965 4,970 4,975 4,980 4,985 4,940 4,945 4,950 4,955 4,960 4,965 4,970 4,975 4,980 4,985 ELEVATION - FEETELEVATION - FEETSUMMARY LOGS OF EXPLORATORY BORINGS LEGEND: BULK SAMPLE COLLECTED FROM AUGER CUTTINGS. DRIVE SAMPLE. THE SYMBOL 10/12 INDICATES 10 BLOWS OF A 140-POUND HAMMER FALLING 30 INCHES WERE REQUIRED TO DRIVE A 2.5-INCH O.D. SAMPLER 12 INCHES. WATER LEVEL MEASURED AT TIME OF DRILLING. CLAYSTONE, MOIST, VERY HARD, GREY THE BORINGS WERE DRILLED ON AUGUST 18TH, 2022 USING 4-INCH DIAMETER CONTINUOUS-FLIGHT AUGERS AND A TRUCK-MOUNTED DRILL RIG. NOTES: CLAY, SANDY AND/OR SILTY, SLIGHTLY MOIST TO WET, MEDIUM STIFF TO VERY STIFF, BROWN (CL) BORING LOCATIONS AND ELEVATIONS ARE APPROXIMATE AND WERE DETERMINED BY A REPRESENTATIVE OF OUR FIRM USING A LEICA GS18 GPS UNITREFERENCINGTHENORTHAMERICAN DATUM OF 1983 (NAD 83). INDICATES MOISTURE CONTENT (%). INDICATES DRY DENSITY (PCF). INDICATES SWELL WHEN WETTED UNDER APPROXIMATE OVERBURDEN PRESSURE (%). INDICATES COMPRESSION WHEN WETTED UNDER APPROXIMATE OVERBURDEN PRESSURE (%). INDICATES LIQUID LIMIT. INDICATES PLASTICITY INDEX. INDICATES PASSING NO. 200 SIEVE (%). INDICATES UNCONFINED COMPRESSIVE STRENGTH (psf). INDICATES WATER-SOLUBLE SULFATE CONTENT (%). 4. SAND, GRAVELLY, CLEAN TO SLIGHTLY SILTY, WET, MEDIUM DENSE TO VERY DENSE, BROWN (SP) WC DD SW COM LL PI -200 UC SS - - - - - - - - - THESE LOGS ARE SUBJECT TO THE EXPLANATIONS, LIMITATIONS AND CONCLUSIONS IN THIS REPORT. WC=14.5DD=103LL=44 PI=24-200=91 WC=3.1-200=7 19/12 30/12 44/12 D-1 El. 4980.4 WC=7.0DD=98-200=73 14/12 WC=4.4-200=7 9/12 44/12 7/12 D-2 El. 4976.3 WC=15.0DD=97-200=82 WC=10.0DD=105-200=84 25/12 WC=4.9-200=5 10/12 24/12 50/8 D-3 El. 4981.6 HIBDON/MASON 24/7 SHELTER CTL|T PROJECT NO. FC10520-125-R1 DRAFT DENVER RESCUE MISSION C/O SHOPWORKS ARCHITECTURE HIBDON/MASON 24/7 SHELTER CTL|T PROJECT NO. FC10,520.000-125-R1 APPENDIX B SUMMARY OF LABORATORY TEST RESULTS AND TABLE B-I DRAFT DRAFT DRAFT DRAFT DRAFT DRAFT DRAFT DRAFT DRAFT UNCONFINED PASSING WATER- MOISTURE DRY LIQUID PLASTICITY APPLIED COMPRESSIVE NO. 200 SOLUBLE MAXIMUM OPTIMUM DEPTH CONTENT DENSITY LIMIT INDEX SWELL* PRESSURE STRENGTH SIEVE SULFATES DENSITY MOISTURE BORING (FEET)(%)(PCF)(%)(PSF)(PSF)(%)(%)(PCF)(%)DESCRIPTION Bulk-1 109.0 16.0 #N/A D-1 2 7.0 98 73 CLAY, SANDY (CL) D-1 4 14.5 103 44 24 91 CLAY, SANDY (CL) D-1 14 3.1 7 SAND, GRAVELLY (SP) D-2 2 15.0 97 82 CLAY, SANDY (CL) D-2 4 4.4 7 SAND, GRAVELLY (SP) D-3 2 10.0 105 84 CLAY, SANDY (CL) D-3 9 4.9 5 SAND, GRAVELLY (SP) P-1 2 6.3 96 25 11 58 CLAY, SANDY (CL) P-1 4 17.7 112 1.8 500 0.20 CLAY, SANDY (CL) P-2 2 11.8 111 6.6 150 0.80 CLAY, SANDY (CL) P-2 4 12.8 102 37 21 75 CLAY, SANDY (CL) P-3 2 11.0 106 30 16 81 CLAY, SANDY (CL) P-3 4 16.5 109 2.1 500 0.64 CLAY, SANDY (CL) P-1 0-4 15.0 112 6,863 CLAY, SANDY (CL) P-2 0-4 15.0 109 5,544 CLAY, SANDY (CL) TH-1 4 17.7 108 1.7 500 CLAY, SANDY (CL) TH-1 9 25.6 96 0.0 1,100 CLAY, SANDY (CL) TH-2 4 16.1 113 3.1 500 CLAY, SANDY (CL) TH-2 9 11.3 3 SAND, GRAVELLY (SP) TH-3 4 17.9 113 2.2 500 CLAY, SANDY (CL) SWELL TEST RESULTS*ATTERBERG LIMITS STD. PROCTOR (ASTM D698) Page 1 of 1 TABLE B-I SUMMARY OF LABORATORY TESTING * NEGATIVE VALUE INDICATES COMPRESSION. DENVER RESCUE MISSION C/O SHOPWORKS ARCHITECTURE HIBDON/MASON 24/7 SHELTER CTL|T PROJECT NO. FC10520-125-R1 DRAFT DENVER RESCUE MISSION C/O SHOPWORKS ARCHITECTURE HIBDON/MASON 24/7 SHELTER CTL|T PROJECT NO. FC10,520.000-125-R1 APPENDIX C FLEXIBLE AND RIGID PAVEMENT MATERIALS, CONSTRUCTION AND MAINTENANCE GUIDELINES DRAFT DENVER RESCUE MISSION C/O SHOPWORKS ARCHITECTURE C-1 HIBDON/MASON 24/7 SHELTER CTL|T PROJECT NO. FC10,520.000-125-R1 MATERIAL GUIDELINES FOR FLEXIBLE AND RIGID PAVEMENTS Aggregate Base Course (ABC) 1. A Class 5 or 6 Colorado Department of Transportation (CDOT) specified ag- gregate base course should be used. A recycled concrete alternative which meets the Class 5 or 6 designation is also acceptable. 2. Aggregate base course should have a minimum Hveem stabilometer value of 78. Aggregate base course or recycled concrete material must be moisture stable. The change in R-value from 300 psi to 100 psi exudation pressure should be 12 points or less. 3. Aggregate base course or recycled concrete should be laid in thin lifts not to exceed 6 inches, moisture treated to within 2 percent of optimum moisture content, and compacted to at least 95 percent of maximum modified Proctor dry density (ASTM D 1557, AASHTO T 180). The material should be placed without segregation. 4. Placement and compaction of aggregate base course or recycled concrete should be observed and tested by a representative of our firm. Placement should not commence until the underlying subgrade is properly prepared and tested. Hot-Mix Asphalt (HMA) 1. HMA should be composed of a mixture of aggregate, filler, hydrated lime and asphalt cement. Mixes shall be designed with 1 percent lime. Some mixes may require polymer modified asphalt cement, or make use of up to 20 per- cent reclaimed asphalt pavement (RAP). A project mix design is recom- mended and periodic checks on the project site should be made to verify com- pliance with specifications. 2. HMA should be relatively impermeable to moisture and should be designed with crushed aggregates that have a minimum of 80 percent of the aggregate retained on the No. 4 sieve with two mechanically fractured faces. 3. Gradations that approach the maximum density line (within 5 percent between the No. 4 and 50 sieves) should be avoided. A gradation with a nominal maxi- mum size of 1 or 2 inches developed on the fine side of the maximum density line should be used. 4. Total void content, voids in the mineral aggregate (VMA) and voids filled should be considered in the selection of the optimum asphalt cement content. The optimum asphalt content should be selected at a total air void content of about 4 percent. The mixture should have a minimum VMA of 14 percent and between 65 percent and 80 percent of voids filled. 5. Asphalt cement should be PG 58-28 for local streets and PG 64-22 for collec- tors and arterials. DRAFT DENVER RESCUE MISSION C/O SHOPWORKS ARCHITECTURE C-2 HIBDON/MASON 24/7 SHELTER CTL|T PROJECT NO. FC10,520.000-125-R1 6. Hydrated lime should be added at the rate of 1 percent by dry weight of the aggregate and should be included in the amount passing the No. 200 sieve. Hydrated lime for aggregate pretreatment should conform to the requirements of ASTM C 207, Type N. 7. Paving should only be performed when subgrade temperatures are above 40°F and air temperature is at least 40°F and rising. 8. HMA should not be placed at a temperature lower than 245°F for mixes con- taining PG 58-28 and PG 64-22 asphalt, and 290°F for mixes containing poly- mer modified asphalt. The breakdown compaction should be completed be- fore the mixture temperature drops 20°F. 9. The maximum compacted lift should be 3 inches and joints should be stag- gered. No joints should be placed within wheel paths. 10. HMA should be compacted to between 92 and 96 percent of Maximum Theo- retical Density. The surface shall be sealed with a finish roller before the mix cools to 185°F. 11. Placement and compaction of HMA should be observed and tested by a rep- resentative of our firm. Placement should not commence until the subgrade is properly prepared, tested and proof-rolled. Portland Cement Concrete (PCC) 1. Portland cement concrete should meet CDOT Class P concrete and have a minimum compressive strength of 4,500 psi at 28 days and a minimum modu- lus of rupture (flexural strength) of 600 psi. A job mix design is recommended and periodic checks on the job site should be made to verify compliance with specifications. 2. Portland cement should be Type II “low alkali” and should conform to ASTM C 150. Portland cement should conform to ASTM C 150. 3. Portland cement concrete should not be placed when the subgrade or air tem- perature is below 40oF. 4. Free water should not be finished into the concrete surface. Atomizing nozzle pressure sprayers for applying finishing compounds are recommended when- ever the concrete surface becomes difficult to finish. 5. Curing of the portland cement concrete should be accomplished by the use of a curing compound. The curing compound should be applied in accordance with manufacturer recommendations. 6. Curing procedures should be implemented, as necessary, to protect the pave- ment against moisture loss, rapid temperature change, freezing, and mechani- cal injury. DRAFT DENVER RESCUE MISSION C/O SHOPWORKS ARCHITECTURE C-3 HIBDON/MASON 24/7 SHELTER CTL|T PROJECT NO. FC10,520.000-125-R1 7. Construction joints, including longitudinal joints and transverse joints, should be formed during construction or sawed after the concrete has begun to set, but prior to uncontrolled cracking. 8. All joints should be properly sealed using a rod back-up and approved epoxy sealant. 9. Traffic should not be allowed on the pavement until it has properly cured and achieved at least 80 percent of the design strength, with saw joints already cut. 10. Placement of portland cement concrete should be observed and tested by a representative of our firm. Placement should not commence until the subgrade is properly prepared and tested. DRAFT DENVER RESCUE MISSION C/O SHOPWORKS ARCHITECTURE C-4 HIBDON/MASON 24/7 SHELTER CTL|T PROJECT NO. FC10,520.000-125-R1 FLEXIBLE PAVEMENT CONSTRUCTION GUIDELINES Experience has shown that construction methods can significantly affect the life and serviceability of a pavement system. A site-specific mix design is recommended and periodic checks during the project should be made to verify compliance with specifications. We rec- ommend the proposed pavement be constructed in the following manner: 1. The subgrade should be stripped of organic matter, scarified, moisture condi- tioned and compacted. Subgrade soils should be moisture conditioned to within 2 percent of optimum moisture content, and compacted to at least 95 percent of maximum modified Proctor dry density (ASTM D 1557). 2. Utility trenches and all subsequently placed fill should be moisture condi- tioned, compacted, and tested prior to paving. As a minimum, fill should be compacted to 95 percent of maximum standard Proctor dry density. 3. After final subgrade elevation has been reached and the subgrade com- pacted, the resulting subgrade should be checked for uniformity and all soft or yielding materials should be replaced prior to paving. Concrete should not be placed on soft, spongy, frozen, or otherwise unsuitable subgrade. 4. If areas of soft or wet subgrade are encountered, the material should be sub- excavated and replaced with properly compacted structural backfill. Where ex- tensively soft, yielding subgrade is encountered, we recommend the excava- tion be inspected by a representative of our office. 5. Aggregate base course should be laid in thin, loose lifts no more than 6 inches, moisture treated to within 2 percent of optimum moisture content, and compacted to at least 95 percent of modified Proctor maximum dry density (ASTM D 1557). 6. Asphaltic concrete should be hot plant-mixed material compacted to between 92 and 96 percent of maximum Theoretical density. The temperature at laydown time should be at least 245F. The surface shall be sealed with a fin- ish roller prior to the mix cooling to 185F. 7. The maximum compacted lift should be 3 inches and joints should be stag- gered. No joints should be within wheel paths. 8. Paving should only be performed when subgrade temperatures are above 40F and air temperature is at least 40F and rising. 9. Subgrade preparation and placement and compaction of all pavement mate- rial should be observed and tested. Compaction criteria should be met prior to the placement of the next paving lift. The additional requirements of the Lar- imer County Urban Area Street Standards should apply. DRAFT DENVER RESCUE MISSION C/O SHOPWORKS ARCHITECTURE C-5 HIBDON/MASON 24/7 SHELTER CTL|T PROJECT NO. FC10,520.000-125-R1 RIGID PAVEMENT CONSTRUCTION GUIDELINES Rigid pavement sections are not as sensitive to subgrade support characteristics as flexible pavement. Due to the strength of the concrete, wheel loads from traffic are distributed over a large area and the resulting subgrade stresses are relatively low. The critical factors affecting the performance of a rigid pavement are the strength and quality of the concrete, and the uniformity of the subgrade. We recommend subgrade preparation and construction of the rigid pavement section be completed in accordance with the following recommenda- tions: 1. The subgrade should be stripped of organic matter, scarified, moisture condi- tioned and compacted. Subgrade soils should be moisture conditioned to within 2 percent of optimum moisture content and compacted to at least 95 percent of maximum modified Proctor dry density (ASTM D 1557). 2. After final subgrade elevation has been reached and the subgrade com- pacted, the resulting subgrade should be checked for uniformity and all soft or yielding materials should be replaced prior to paving. Concrete should not be placed on soft, spongy, frozen, or otherwise unsuitable subgrade. 3. The subgrade should be kept moist prior to paving. 4. Curing procedures should protect the concrete against moisture loss, rapid temperature change, freezing, and mechanical injury for at least 3 days after placement. Traffic should not be allowed on the pavement for at least one week. 5. Curing of the portland cement concrete should be accomplished by use of a curing compound in accordance with manufacturer recommendations. 6. Construction joints, including longitudinal joints and transverse joints, should be formed during construction or should be sawed shortly after the concrete has begun to set, but prior to uncontrolled cracking. All joints should be sealed. 7. Construction control and inspection should be performed during the subgrade preparation and paving procedures. Concrete should be carefully monitored for quality control. The additional requirements of the Larimer County Urban Area Street Standards should apply. The design sections are based upon 10-year and 20-year periods. Experience in the Denver area indicates virtually no maintenance or overlays are necessary for a 20-year de- sign period. We believe some maintenance and sealing of concrete joints will help pavement performance by helping to keep surface moisture from wetting and softening or heaving sub- grade. To avoid problems associated with scaling and to continue the strength gain, we rec- ommend deicing salts not be used for the first year after placement. DRAFT DENVER RESCUE MISSION C/O SHOPWORKS ARCHITECTURE C-6 HIBDON/MASON 24/7 SHELTER CTL|T PROJECT NO. FC10,520.000-125-R1 MAINTENANCE GUIDELINES FOR FLEXIBLE PAVEMENTS A primary cause for deterioration of pavements is oxidative aging resulting in brittle pavements. Tire loads from traffic are necessary to "work" or knead the asphalt concrete to keep it flexible and rejuvenated. Preventive maintenance treatments will typically preserve the original or existing pavement by providing a protective seal or rejuvenating the asphalt binder to extend pavement life. Annual Preventive Maintenance • Visual pavement evaluations should be performed each year. • Reports documenting the progress of distress should be kept current to pro- vide information on effective times to apply preventive maintenance treat- ments. • Crack sealing should be performed annually as new cracks appear. 3 to 5-Year Preventive Maintenance • The owner should budget for a preventive treatment (e.g. chip seal, fog seal, slurry seal) at approximate intervals of 3 to 5 years to reduce oxidative embrit- tlement problems. 5 to 10-Year Corrective Maintenance • Corrective maintenance (e.g. full-depth patching, milling and overlay) may be necessary, as dictated by the pavement condition, to correct rutting, cracking and structurally failed areas. DRAFT DENVER RESCUE MISSION C/O SHOPWORKS ARCHITECTURE C-7 HIBDON/MASON 24/7 SHELTER CTL|T PROJECT NO. FC10,520.000-125-R1 MAINTENANCE GUIDELINES FOR RIGID PAVEMENTS High traffic volumes create pavement rutting and smooth, polished surfaces. Preven- tive maintenance treatments will typically preserve the original or existing pavement by providing a protective seal and improving skid resistance through a new wearing course. Annual Preventive Maintenance • Visual pavement evaluations should be performed each spring or fall. • Reports documenting the progress of distress should be kept current to pro- vide information of effective times to apply preventive maintenance. • Crack sealing should be performed annually as new cracks appear. 4 to 8 Year Preventive Maintenance • The owner should budget for a preventive treatment at approximate intervals of 4 to 8 years to reduce joint deterioration. • Typical preventive maintenance for rigid pavements includes patching, crack sealing and joint cleaning and sealing. • Where joint sealants are missing or distressed, resealing is mandatory. 15 to 20 Year Corrective Maintenance • Corrective maintenance for rigid pavements includes patching and slab re- placement to correct subgrade failures, edge damage and material failure. • Asphalt concrete overlays may be required at 15 to 20 year intervals to im- prove the structural capacity of the pavement. DRAFT