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HomeMy WebLinkAboutSoils Reportq AMERICAN CEOSER\1ICES Geotechnical Evaluation Report 33 4 Wheel Drive Rd, Carbondale, CO 81629 Date: February 12,2024; Project No: 0125-WS24 AMERICAN GECSERVICES CFOTFCHNICAL & MATERIALS ENVIRONMENTAL STRUCTURAL ct\4t. F,NCINEERING AND SCIENCE 8882764027 February 12,2024 PROJECT NO: 0314-WS20 CLIENT: Mr. Scott Hankinson Reference: Geotechnical Evaluation Report, 33 4 Wheel Drive Rd, Carbondale, CO 81623 Dear Mr. Hankinson, At your request, we have completed the geotechnical evaluation for the referenced project in accordance with the American GeoServices, LLG (AGS) Proposal. Results of our evaluation and design recommendations are summarized below' PROJECT INFORMATION The site is located as shown in Figure 1 and Figure 2. The proposed development will consist of residential pool/spa construction. We do not anticipate significant site grading for this project' We anticipate the proposed structure will be constructed with light to moderate foundation loads. SCOPE OF WORK Our scope of services included the geologic literature review, soil explorations, geologic hazards evaluation, geotechnical evaluation, and the preparation of this report. Evaluation of any kind of existing structures on and adjacent to the site was beyond our scope of services. ln February 2024,we performed two soil explorations (81 and 82) at approximate locations shown in Figure 2 and collected soil/rock samples. Our soil exploration included logging of soils from soil boring and evaluation of the exposed driveway cuts and other ground cuts. Our explorations extended to a maximum depth of 5 feet below existing ground surface (BGS). All soil/rock samples were identified in the field and were placed in sealed containers and transported to the laboratory for further testing and classification. Logs of all soil explorations showing details of www.americangeoservices.com sma@americangeoservices.com Ph: (888) 276 4027 Fxt (877) 47I 0369 subsurface soil conditions encountered at the site are included in an appendix. The Legend and Notes necessary to interpret our Exploration Logs are also included in an appendix. Data obtained from site observations, subsurface exploration, laboratory evaluation, and previous experience in the area was used to perform engineering analyses. Results of engineering analyses were then used to reach conclusions and recommendations presented in this report. SURFACE CONDITIONS The site is roughly an irregularly shaped parcel of land as shown in Figure 2. Currently the site topography is gently to moderately sloping downwards to the north. At the time of our site visit, there was no visual indication of active slope instability or active landslides in the site vicinity. However, our review of available geology maps and geologic hazards information revealed the presence of landslide geologic hazards and evaporite-related hazards at or immediately adjacent to the site. SUBSURFACE CONDITIONS Subsurface conditions encountered in our explorations and noted in our literature research are described in detail in the Exploration Logs provided in an Appendix and in the following paragraphs. Soil classification and identification is based on commonly accepted methods employed in the practice of geotechnicalengineering. ln some cases, the stratigraphic boundaries shown on Exploration Logs represent transitions between soil types rather than distinct lithological boundaries. lt should be recognized that subsurface conditions often vary both with depth and laterally between individual exploration locations. The following is a summary of the subsurface conditions encountered at the site. Alluvium: Site is primarily underlain by generally medium stiff mixtures of sand-silt (SM, ML) extending to depths of about 1.5-2.5 feet. These soils exhibited low plasticity in the field and in the laboratory. These soils do not represent old debris flow deposit or ancient landslide deposit. Gompfetely to Partially Weathered Bedrock: Below about 1.5-2.5 feet, the site is generally underlain by completely to partially weathered sandstone/mudstone/siltstone formations extending to depths of several tens of feet. Groundwater: Groundwater was not encountered during exploration or at the time of completion of our soil explorations. This observation may not be indicative of other times or at locations other than the site. Some variations in the groundwater level may be experienced in the future. The magnitude of the variation will largely depend upon the duration and intensity of precipitation, temperature and the surface and subsurface drainage characteristics of the surrounding area. Project No: 0125-WS24 February 12,2024 Page No: 2 of 18 GEOLOGIC HAZARDS EVALUATION Expansive/Gollapsible Soils: The site is not underlain by highly expansive clayey soils or clayey sedimentary bedrock materials. The site location is not near known swell hazard zones that pose a significant geotechnical concern. However, local pockets of 'collapsible' soils/materials can occur through the site and may cause settlement in the foundations or flatwork around the site. This is typical of many areas along the Roaming Fork River corridor. Flooding: Proposed construction area is not located within 1O0-yearflood hazard zone; however, a flood hazard evaluation was beyond our scope of services. We recommend hiring an experienced hydrologist to evaluate the flood hazards for the site, or an in-depth evaluation of published flood hazard maps, considering the proximity of the site to the river. Debris Flow: Site is not located within alluvial fans or flood channels. Debris flow hazard at the site is minimal under normal site, topographic, geologic, and weather conditions. However, the site vicinity area may consist of ancient debris flow or ancient landslide deposit, which is currently inactive. Rockfall: Site is not located within rockfall hazard zone. Rockfall hazard atthe site is minimal under normal site, topographic, geologic, and weather conditions. Landsf ides: Our review of available geologic maps and landslide hazard maps did not indicate that recent landslides or recent debris flow had occurred at the site or in the immediate proposed building area. During our site reconnaissance, we did not notice scarps, crevices, depressions, tension cracks in the ground surface, irregular slope toes, exposed surfaces of ruptures without vegetation, presence of distinct fast-growing vegetation, undrained depressions, etc., that are generally indicative of local active and/or inactive landslides or slope instability that would adversely impact the on-site structure at this time, however, a detailed landslide evaluation of any kind or slope stability evaluation under seismic conditions was beyond our scope of services. However, the site is located within the mapped landslide hazard areas surrounding the site (Figure 6). There are potentially mapped landslides and/or ancient landslide deposits close to the site boundaries or within the site boundaries. There is also moderate to high potential for the presence of ciormani ancjior unknown hisioric iancisiicies, deep-seated ancient iandsiides, oi'geologically"- recently developed dormant landslides in the site vicinity close to the site. The site itself is mapped as being situated within the possibly existing active or ancient active landslide mass or an ancient active global landslide. Considering these findings, the site topography, and site geologic conditions, it is our opinion that the site area have 'site-specific Project No: 0125-WS24 February 12,2024 Page No: 3 of 18 landslide hazards' and has some 'inherent' risk associated with slope instability and structural impact from the movement of any global/ancient landslide and local slope movements. Moreover, historically, with construction in such areas, there is always an inherent risk associated with ground movement and/or settlements and related structural damage. The owner should understand these inherent risks related to site vicinity. lf the owner wants to better understand the risks and to eliminate the site-specific landslide hazard risks, then a detailed and comprehensive geotechnical evaluation including deep drilling, detailed slope stability modeling, and a detailed geologic hazards assessment (including global landslide hazards evaluation) should be performed in the site vicinity area to quantify the abovementioned risks and to provide detailed geotechnical design recommendations for comprehensive mitigation measures. Unless these recommended studies are performed, the owner is completely responsible for taking any and all risks associated with any future potential for instability at the site occurring due to landslide hazards in the site vicinity. Evaporite Formations: The site and/or the immediate vicinity area are underlain by Evaporite Formations which consist of significant volumes of relatively highly water-soluble minerals including gypsum, anhydrite and halite (rock salt) interbedded with siltstones and sandstones. These formations are highly susceptible to forming sinkholes due to dissolution of soluble minerals in the bedrock. At the time of our site visit, we did not notice any sinkholes or small depressions in the proposed construction area. lt should be noted that detailed evaluation of this geologic hazard was beyond our scope of services. Historically, with construction in such areas, there is always an inherent risk associated with settlements and related structural damage. The owner should understand these inherent risks related to the site and site vicinity. lf the owner wants to better understand the risks and to eliminate the site-specific sinkhole hazard risks, then a detailed and comprehensive geotechnical evaluation including deep drilling, detailed modeling, and a detailed evaporite hazard assessment should be performed to quantify the abovementioned risks and to provide detailed geotechnical design recommendations for comprehensive mitigation measures. Unless these recommended studies are performed, the owner is completely responsible for taking any and all risks associated with any future potential for instability at the site occurring due to this geologic hazard. Earthquakes: Based on site geology, topography, and our preliminary evaluation, in our opinion, the site is generally not considered to be located within a highly active seismic area. Therefore, anticipated ground motions in the region due to seismic activity are relatively low and do not pose a significanthazard. Ground accelerations in excess of 0.19 to -0.29 are not anticipated to occur at the site. Project No: 0125-WS24 February 12,2024 Page No: 4 of 1 8 Based on the results of our subsurface explorations and review of available literature (Gurrent lnternational Building Code), in our opinion, a site classification "C" may be used for this project. However, this site classification may be revised by performing a site-specific shear wave velocity study. Subsurface soil conditions at the site are not susceptible to liquefaction. Seismically induced slope instability may occur on a global scale impacting not just the site but also the surrounding area, however, such an evaluation was beyond our scope of services. A detailed seismic hazards evaluation of the site was beyond the scope of services. CONCLUSIONS AND RECOMMENDATIONS Based on the results of our geotechnical evaluation, in our opinion, the site is suitable for the proposed construction provided the following recommendations are strictly followed. lt should be noted that our conclusions and recommendations are intended as design guidance. They are based on our interpretation of the geotechnical data obtained during our evaluation and following assumptions: . ProposediFinal site grades will not differ significantly from the current site grades; . Proposed foundations will be constructed on level ground; and o Structural loads will be static in nature. Construction recommendations are provided to highlight aspects of construction that could affect the design of the project. Entities requiring information on various aspects of construction must make their own interpretation of the subsurface conditions to determine construction methods, cost, equipment, and work schedule. Pool Retaining Walls and Subgrades: Considering the presence of medium to high expansive soils near the surface. Moreover, the site is located within a swell hazard zone (Figure 5). Considering these site conditions, we recommend that the proposed pool retaining wall footings and pool subgrades should be designed and constructed in accordance with following criteria: Excavate the subgrade and call us for the inspection and approval of the prepared subgrade prior to the placement of concrete. Foundations bearing upon properly prepared and approved subgrade should be designed for a maximum allowable bearing pressure of 2,000 pounds per square foot (psf). Project No: 0125-WS24 February 12,2024 Page No: 5 of 1 B a a Estimated final structural loads will dictate the final form and size of foundations to be constructed. However, as a minimum, we recommend bearing walls be supported by continuous footings of at least 16 inches in width. Continuous foundation walls should be reinforced in the top and bottom to span an unsupported length of at least 8 feet to further aid in resisting differential movement. Exterior footings should extend below design frost depth of 36 inches. We understand the retaining walls will be designed to be rigid (unyielding), and not free to rotate. Retaining walls for at-rest conditions can be designed to resist an equivalent fluid density of 55 pcf for on-site fill materials if needed only imported granular backfill meeting CDOT Class 1 structural backfill should be used. Retaining walls for unrestrained conditions (free lateral movement) can be designed to resistan equivalentfluid densityof 35 pcf foron- site fill materials and 35 pcf for imported granular backfill or CDOT Class 1 structural backfill. For passive resistance of unrestrained walls, we recommend passive resistance of 300 psf per foot of wall height. A coefficient of friction value of 0.35 may be used for contact between the prepared soil surface and concrete base. The above recommended values do not include a factor of safety or allowances for surcharge loads such as adjacent foundations, sloping backfill, vehicle traffic, or hydrostatic pressure. We should be contacted to provide additional recommendations for any specific site retaining conditions. Retaining wall backfill should be placed in strict accordance with our earthwork recommendations given below. Backfill should not be over-compacted in order to minimize excessive lateral pressures on the walls. Retaining walls should be adequately designed as retaining walls with adequate drainage measures implemented. As a precautionary measure, a drainage collection system (drains or geosynthetic drains) should be included in the wall design in order to minimize hydrostatic pressures. A prefabricated drainage composite or drain board such as the MiraDrain 2000 or an engineer-approved equivalent may be installed along the backfilled side of the retaining walls. a a a a a We estimate total settlement for footings designed and constructed as discussed in this section will be one inch or less, with differential settlements on the order of one-half to three-fourths of the total settlement, not considering landslide hazards and evaporite hazards. Project No: 0125-WS24 February 12,2024 Page No: 6 of 18 Pool Deck: We provide following recommendations for Pool deck areas: a a a a a a Pool deck should be designed and constructed to move independently of pool structure and reinforced to function as an independent unit. Provide slip joints around adjacent structures to allow free vertical movement of the deck. Deck should be designed as 'square' reinforced panels instead of 'rectangular' reinforced panels. Frequent control joints should be provided to reduce problems with shrinkage and cracking according to ACI specifications. Controljoint spacing is a function of slab thickness, aggregate size, slump and curing conditions. The requirements for concrete deck thickness, joint spacing, and reinforcement should be established by the designer, based on experience, recognized design guidelines and the intended slab use. Placement and curing conditions will have a strong impact on the final concrete slab integrity. Deck slabs should be adequately reinforced with welded wire mesh and steel rebar. Structural engineer should include steel rebar in addition to welded wire mesh in order to reduce the risk of differential movement due to bending over 8 feet of unsupported length. Plumbing passing through deck areas should be isolated from the deck slabs and provided with flexible connections to allow for movement. Under deck plumbing should be avoided if possible and should be brought above the deck as soon as possible. Where mechanical/plumbing equipment is supported on deck slabs, we recommend provision of flexible connections with a minimum of 2 inches of allowance for vertical movement. Above recommendations should significantly reduce the potential for cracking pool deck/slabs. However, pool deck cracking cannot be eliminated. Therefore, whenever cracking occurs, immediate measures should be taken to seal the cracks. On a regular basis, all cracks and controljoints should be sealed to minimize water seepage into the subgrades. Pool deck will require maintenance throughout design life. Drainage and Moisture Control: Considering the presence of evaporite hazard at the site and in the site vicinity area, we recommend following drainage and moisture control measures, as a minimum. Any evaporite related hazards and damage caused by that is owner's full responsibility: The entire pool shell and the drainage envelope around the pool should be underlain by an :--^--^^Ll^ -^-L-^^^ ^. '^L ^^ lJ.,^^lan I inar /ar aa' 'irralan{\llllpVllllgaUlU llltilllLlldllti DUt/ll CrD I lyPalUll Llllsl \vr EVurvqrvrrr./' A perimeter underdrain/dewatering system and a base underdrain system should be installed above the Hypalon Liner at the base of the pool and behind the retaining walls to reduce the potential for water seepage into the underlying bedrock strata. The perimeter and base underdrain/dewatering system should be properly designed and connected to the area Project No: 0125-WS24 February 12,2024 Page No: 7 of 18 a a a a a underdrain system (if present) or a sump-pump system for suitable discharge from the pool area. As a minimum, the subsurface drainage system should consist typically of 4-inch minimum diameter perforated rigid PVC or flexible pipes (rigid preferred due to depth of placement) surrounded by at least one pipe diameter of free draining gravel. The pipe should be wrapped in a geosynthetic to prevent fine soils from clogging the system in the future. The pipe should drain by gravity to a suitable all-weather outlet or a sump-pit. Surface cleanouts of the perimeter drain should be installed at minimum serviceability distances around the structure. A properly constructed drain system can result in a reduction of moisture infiltration of the subsurface soils. The entire design and construction team should evaluate, within their respective field of expertise, the current and potential sources of water throughout the life of the structure and provide any design/construction criteria to alleviate the potential for moisture changes. lf recommended drain systems are used, the actual design/layout, outlets, locations, and construction means and methods should be observed by a representative of AGS. Proper surface drainage should be maintained at this site during and after completion of construction operations. The ground surface adjacent to pool areas should be sloped to promote rapid run-off of surface water. We recommend a minimum slope of six inches in the first five horizontal feet for landscaped or graveled areas. These slopes should be maintained during the service life of pool structures. Landscaping should be limited around building areas to either xeri-scaping, landscaping gravel, or plants with low moisture requirements. lrrigation should be minimal and limited to maintain plants. Roof downspouts of adjacent residential structures should discharge on splash-blocks or other impervious surfaces and directed away from the pool areas. Ponding of water should not be allowed immediately adjacent to pool areas. It is important to follow these recommendations to minimize wetting or drying of the foundation and subgrade elements throughout the life of the facility. Construction means and methods should also be utilized which minimize improper increases/decreases in the moisture contents of the soils during construction. Again, positive drainage away from the new structures is essential to their successful long- term performance and should be provided during the life of the structure. Deck areas, paved areas, or landscape areas within 10 feet of structures should slope at a minimum grade of 10H:1V away from pool structure. Once again, downspouts from all roof drains of adjacent residential structures, if any, should discharge all water away from the pool areas. Drainage should be created such that surface and subsurface water is diverted away from the pool areas. Project No: 0125-WS24 February 12,2024 Page No: 8 of 18 SHALLOW FOUNDATIONS a Foundations bearing upon properly prepared and approved subgrade should be designed for a maximum allowable bearing pressure of 2,000 pounds per square foot (psf). o Estimated final structural loads will dictate the final form and size of foundations to be constructed. However, as a minimum, we recommend bearing walls be supported by continuous footings of at least 18 inches in width. lsolated columns should be supported on pads with minimum dimensions of 24 inches square. r Exterior footings and footings in unheated areas should extend below design/preferred frost depth of 36 inches. . Continuous foundation walls should be reinforced in the top and bottom to span an unsupported length of at least 8 feet to further aid in resisting differential movement. As a minimum, additional reinforcement as shown in Figure 7 should be placed. r Foundation/stem walls should be adequately designed as retaining walls and adequate drainage measures should be implemented as shown in Figure L We estimate total seftlement for foundations designed and constructed as discussed in this section will he one inch or less, with differential settlements on the order of one-half to three- fourths of the total settlement, not considering landslide hazards and evaporite hazards. STRUCTURAL FLOOR & CRAWL SPACE (lF REQUIRED) We understand a structural/framed floor with crawl space may be used for this project. The grade beams (if used) and floor system should be physically isolated from the underlying soil materials with crawl-space type construction. The void or crawl space of minimum of 6 inches or whatever minimum current Uniform Building Code (UBC) requirement is. For crawl-space construction, various items should be considered in the design and construction that are beyond the scope of geotechnical scope of work for this project and require specialized expertise. Some of these include design considerations associated with clearance, ventilation, insulation, standard construction practice, and local building codes. lf not properly drained and constructed, there is the potential for moisture to develop in crawlspaces through transpiration of the moisture/groundwater within native soils underlying the structure, water intrusion from snowmeit anci precipiiation, anci suriace runoii or infiitration of waier through ii-i-igation of iawr-rs and landscaping. ln crawl space, excessive moisture or sustained elevated humidity can increase the potential for mold to develop on organic building materials. A qualified professional engineer in building systems should address moisture and humidity issues. Pro.ject No: 0125-WS24 February 12,2024 Page No: 9 of 1 8 GRAWL SPACE PERIMETER/UNDERDRAIN SYSTEM (lF REQUIRED) ln order for the crawl space to remain free of moisture, it is important that drainage recommendations are properly implemented, and adequate inspections are performed priorto the placement of concrete As a minimum, subgrade beneath a structural floor system should be graded so that water does not pond. Perimeter drains and under-slab drains should be installed in conjunction with a sump pump system to eliminate the potential for ponding and any subsequent damage to foundation and slab elements. The lot-specific perimeter dewatering, and underdrain systems should be properly designed and connected to the area underdrain system or a sump-pump system for suitable discharge from the lot. a a a a SLAB-ON-GRADE AND PERTMETER/UNDERDRAIN SYSTEM (lF REQUIRED) Groundwater is not expected to be at depths below the proposed foundation levels if excavation is performed during dry seasons. ln order to assure proper slab-on-grade construction (if used), following recommendations should be strictly followed: A perimeter dewatering system should be installed to reduce the potential for groundwater entering slab-on-grade areas. The lotspecific perimeter dewatering should be properly Drainage recommendations illustrated in Figure 8 should be implemented. The subsurface drainage system should consist typically of 4-inch minimum diameter perforated rigid PVC or flexible pipe (rigid preferred due to depth of placement) surrounded by at least one pipe diameter of free draining gravel. The pipe should be wrapped in a geosynthetic to prevent fine soils from clogging the system in the future. The pipe should drain by gravity to a suitable all- weather outlet or a sump-pit. Surface cleanouts of the perimeter drain should be installed at minimum serviceability distances around the structure. A properly constructed drain system can result in a reduction of moisture infiltration of the subsurface soils. Drains which are improperly installed can introduce settlement or heave of the subsurface soils and could result in improper surface grading only compounding the potential issues. The underdrain system should consist of adequate lateral drains and a main drain, regular clean out and inspection locations, and proper connections to the sump-pump system for discharge into suitable receptacles located away from the site. The entire design and construction team should evaluate, within their respective field of expertise, the current and potential sources of water throughout the life of the structure and provide any design/construction criteria to alleviate the potential for moisture changes. lf recommended drain systems are used, the actual design/layout, outlets, locations, and construction means, and methods should be observed by a representative of AGS. Project No: 0125-WS24 February 12,2024 Page No: 10 of 18 a a a designed and connected to the area underdrain system or a sump-pump system for suitable discharge from the lot. As a minimum, drainage recommendations illustrated in Figure 8 should be implemented. The subsurface drainage system should consist typically of 4-inch minimum diameter perforated rigid PVC or flexible pipe (rigid preferred due to depth of placement) surrounded by at least one pipe diameter of free draining gravel. The pipe should be wrapped in a geosynthetic to prevent fine soils from clogging the system in the future. The pipe should drain by gravity to a suitable all-weather outlet or a sump-pit. Surface cleanouts of the perimeter drain should be installed at minimum serviceability distances around the structure. A properly constructed drain system can result in a reduction of moisture infiltration of the subsurface soils. Drains which are improperly installed can introduce settlement or heave of the subsurface soils and could result in improper surface grading only compounding the potential issues. The entire design and construction team should evaluate, within their respective field of expertise, the current and potential sources of water throughout the life of the structure and provide any design/construction criteria to alleviate the potential for moisture changes. lf recommended drain systems are used, the actual design/layout, outlets, locations, and construction means, and methods should be observed by a representative of AGS. The "Slab Performance Risk" associated with native soils is "Low". Therefore, the slab can be constructed as a slab-on-grade provided the owner is aware that there is still potential risk of some slab movement due to presence of possibly collapsible soils. The actual slab movements that will occur on a particular project site are very difficult, if not impossible, to predict accurately because these movements depend on loads, evapo- transpiration cycles, surface and subsurface drainage, consolidation characteristics, swell index, swell pressures and soil suction values. The actual time of year during which the slab-on-grade is constructed has been found to have a large influence on future slab-on-grade movements. Slab heaves or settlements are normally defined in terms of "total" and "differential" movement. "Total" movement refers to the maximum amount of heave or settlement that the slab may experience as a whole. "Differential" movement refers to unequal heave or settlement that different points of the same slab may experience, sometimes over relatively short horizontal distances. Differential movements are arbitrarily determined to be one-half of the total movement in soils exhibiting Low Slab Performance Risk. Greater differential movements can occur in areas where expansive soils have been encountered and where the natural soils abruptly transition to fill material. For design of floor slabs, a modulus of subgrade reaction of 200 pounds per cubic inch (pci) may be used. Based on the results of our analyses, we believe that interior floor slabs designed as Project No: 0125-WS24 February 12,2024 PageNo:11of18 recommended above and constructed as recommended in following paragraphs could result in "total" movement of approximately up to 1-inch with "differential" movement on the order of half the total movement. We recommend that the construction measures outlined in the following paragraphs be followed to reduce potential damage to floor slabs, should excessive wetting of the subsurface soils occur: r Design and construct the floor slab to move independently of bearing members (floating slab construction). Provide slip joints around exterior walls and interior columns to allow free vertical movement of the slabs. Frequent controljoints should be provided at about 10 feet spacing in the floor slab to reduce problems with shrinkage and cracking according to ACI specifications. Controljoint spacing is a function of slab thickness, aggregate size, slump and curing conditions. The requirements for concrete slab thickness, joint spacing, and reinforcement should be established by the designer, based on experience, recognized design guidelines and the intended slab use. Placement and curing conditions will have a strong impact on the final concrete slab integrity. Floor slabs should be adequately reinforced with welded wire mesh and steel rebar. Structural engineer should include steel rebar in addition to welded wire mesh in order to reduce the risk of differential movement due to bending over I feet of unsupported length. The need for a vapor barrier will depend on the sensitivity of floor coverings to moisture. lf moisture sensitive floor coverings are proposed for portions of the proposed structure, a capillary break material, typically consisting of "clean" gravel, should be considered. We can provide additional recommendations if this is the case. a o a Provided gravel is desired below the slab, a layer of 4 to 6 inches can be used. Plumbing passing through slabs should be isolated from the slabs and provided with flexible connections to allow for movement. Under slab plumbing should be avoided if possible and should be brought above the slab as soon as possible. lf slab-bearing partitions are used, they should be designed and constructed to allow for movement. A minimum of 2 inches of void space (as illustrated in Figure 3) should be maintained below or above partitions. lf the void is provided at the top of partitions, the connections between the interior, slab-supported partitions and exterior foundation supported walls should allow for differential movement. Where mechanical equipment and HVAC equipment are supported on slabs, we recommend provision of a flexible connection between the furnace and ductwork with a minimum of 2 inches of vertical movement. Project No: 0125-WS24 February 12,2024 Page No: 12ol 18 RETA|NTNG WALL (tF REQUIRED) Retaining walls for at-rest conditions can be designed to resist an equivalent fluid density of 55 pcf for on-site fill materials if needed only imported granular backfill meeting CDOT Class 1 structural backfill should be used. Retaining walls for unrestrained conditions (free lateral movement) can be designed to resist an equivalent fluid density of 35 pcf for on-site fill materials and 35 pcf for imported granular backfill or GDOT Class 1 structural backfill. For passive resistance of unrestrained walls, we recommend passive resistance of 300 psf per foot of wall height. A coefficient of friction value of 0.35 may be used for contact between the prepared soil surface and concrete base. The above recommended values do not include a factor of safety or allowances for surcharge loads such as adjacent foundations, sloping backfill, vehicle traffic, or hydrostatic pressure. We should be contacted to provide additional recommendations for any specific site retaining conditions. Retaining wall backfillshould be placed in strict accordance with our earthwork recommendations given below and as illustrated in Figure 8. Backfill should not be over-compacted in order to minimize excessive lateral pressures on the walls. As a precautionary measure, a drainage collection system (drains or geosynthetic drains) should be included in the wall design in order to minimize hydrostatic pressures. A prefabricated drainage composite or drain board such as the MiraDrain 2000 or an engineer-approved equivalent may be installed along the backfilled side of the basement foundation wall. EARTHWORK CONSTRUCTION Site grading should be carefully planned so that positive drainage away from all structures is achieved. The following earthwork recommendations should be followed for all aspects of the project. Fill material should be placed in uniform horizontal layers (lifts) not exceeding 8 inches before compacting to the required density and before successive layers are placed. lf the contractor's equipment is not capable of properly moisture conditioning and compacting 8-inch lifts, then the lift thickness shall be reduced until satisfactory results are achieved. Clays or weathered sandstone/claystone bedrock (if encountered) should not be re-used onsite except in landscaped areas. lmported soils should be approved by AGS prior to placement. Frl/ placement observations and fill compacfion fesfs should be performed by AGS Engineering in order to minimize the potential for future problems. Fill material should not be placed on frozen Project No: 0125-WS24 February 12,2024 Page No: 13 of 18 ground. Vegetation, roots, topsoil, the existing fill materials, and other deleterious material to depth of approximately 6 inches should be removed before new fill material is placed. On-site fill to be placed should be moisture treated to within 2 percent of optimum moisture content (OMC) for sand fill and from OMC to 3-4 percent above OMC for clay and weathered bedrock. Fill to be placed in wall backfill areas and driveway areas and all other structural areas should be compacted to 95% of Standard Proctor (ASTM D 698) dry density or greater. Compaction in landscape areas should be 85% or greater. lmported structural fill should consist of sand or gravel material with a maximum particle size of 3 inches or less. ln addition, this material shall have a liquid limit of less than 30 and a plasticity index of 15 or less. Structural fill should also have a percent fine between 15 to 30 percent passing the No. 200 sieve. Structural fill should be moisture conditioned to within 2 percent of OMC and compacted to at least 95 percent of Standard Proctor (ASTM D698) dry density. ln our opinion, the materials encountered at this site may be excavated with conventional mechanical excavating equipment. For deeper excavations, heavier equipment with toothed bucket may be required. Although our soil explorations did not reveal "buried" foundation elements or other structures or debris within the building footprint, these materials may be encountered during excavation activities. Debris materials such as brick, wood, concrete, and abandoned utility lines, if encountered, should be removed from structural areas when encountered in excavations and either wasted from the site or placed in landscaped areas. Temporary excavations should comply with OSHA and other applicable federal, state, and local safety regulations. ln our opinion, OSHA Type A/B soils should be encountered at this site during excavation. OSHA recommends maximum allowable unbraced temporary excavation slopes of 1 : 1 (H:V) for Type A/B soils for excavations up to 1 0 feet deep. Permanent cut and fill slopes are anticipated to be stable at slope ratios as steep as 2H:1V (horizontal to vertical) under dry conditions. New slopes should be revegetated as soon as possible after completion to minimize erosion. We recommend a minimum of 12feet of clearance between the top of excavation slopes and soil stockpiles or heavy equipment or adjacent structures. This setback recommendation may be revised by AGS once the project plans are available for review. lf braced excavations or shoring systems are to be used or needed, they should be reviewed and designed by AGS. lt should be noted that near-surface soils encountered at the site will be susceptible to some sloughing and excavations should be periodically monitored by AGS's representative. Project No: 0125-W524 February 12,2024 Page No: 14 of 18 The proposed excavation should not adversely impact any existing structures. Proper shoring and/or underpinning should be used to maintain the stability of the existing structure as well as the excavated faces of the new construction area. It should be noted that the above excavation recommendations are commonly provided by local consultants. The evaluation of site safety during construction, stability of excavated slopes and cuts, and overall stability of the adjacent areas during and after construction is beyond our scope of services. At your request, we can provide these services at an additional cost. During construction in wet or cold weather, grade the site such that surface water can drain readily away from the building areas. Promptly pump out or otherwise remove any water that may accumulate in excavations or on subgrade surfaces and allow these areas to dry before resuming construction. Berms, ditches and similar means may be used to prevent storm water from entering the work area and to convey any water off-site efficiently. lf earthwork is performed during the winter months when freezing is a factor, no grading fill, structural fill or other fill should be placed on frosted or frozen ground, nor should frozen material be placed as fill. Frozen ground should be allowed to thaw or be completely removed prior to placement of fill. A good practice is to cover the compacted fill with a "blanket" of loose fill to help prevent the compacted fill from freezing overnight. The "blanket" of loose fill should be removed the next morning prior to resuming fill placement. During cold weather, foundations, concrete slabs-on-grade, or other concrete elements should not be constructed on frozen soil. Frozen soil should be completely removed from beneath the concrete elements, or thawed, scarified and re-compacted. The amount of time passing between excavation or subgrade preparation and placing concrete should be minimized during freezing conditions to prevent the prepared soils from freezing. Blankets, soil cover or heating as required may be utilized to prevent the subgrade from freezing. GENERAL DRAINAGE Proper drainage is criticalfor achieving long-term stability and overall success. ln general, where interior floor elevations are situated at an elevation below proposed exterior grades, we recommend installation of perimeter drains around the exterior grade beam and foundations as illustrated in Figure 8. ln addition, drain laterals that span the crawl space are recommended to prevent ponding of water within the crawlspace (if used). lf necessary, AGS can provide further recommendations for the exterior drain system and a typical drain detail. Project No: 0125-WS24 February 12,2024 Page No: 15 of 18 Groundwater was encountered at depth at the time of our explorations. However, based on the weather and surface water run-off conditions in the site vicinity area during construction, site may require pumping and other dewatering methods during construction. Proper surface drainage should be maintained at this site during and after completion of construction operations. The ground surface adjacent to buildings should be sloped to promote rapid run-off of surface water. We recommend a minimum slope of six inches in the first five horizontal feet for landscaped or graveled areas. These slopes should be maintained during the service life of buildings. lf necessary, adequate interceptor drains should be installed on uphill sides to intercept any surface water run-off towards the site. Landscaping should be limited around building areas to either xeri-scaping, landscaping gravel, or plants with low moisture requirements. No trees should be planted or present within 15 feet of the foundations. lrrigation should be minimal and limited to maintain plants. Roof downspouts should discharge on splash-blocks or other impervious surfaces and directed away from the building. Ponding of water should not be allowed immediately adjacent to the building. It is important to follow these recommendations to minimize wetting or drying of the foundation elements throughout the life of the facility. Construction means and methods should also be utilized which minimize improper increases/decreases in the moisture contents of the soils during construction. Again, positive drainage away from the new structures is essential to the successful performance of foundations and flatwork and should be provided during the life of the structure. Paved areas and landscape areas within 10 feet of structures should slope at a minimum grade of 10H:1V away from foundations. Downspouts from all roof drains, if any, should cross all backfilled areas such that they discharge all water away from the backfill zones and structures. Drainage should be created such that water is diverted away from building sites and away from backfill areas of adjacent buildings. CONCRETE CONSTRUCTION Concrete sidewalks and any other exterior concrete flatwork around the proposed structure may experience some differential movement and cracking. While it is not likely that the exterior flatworks can be economically protected from distress, we recommend following techniques to reduce the potential long-term movement: Scarify and re-compact at least 12 inches of subgrade material located immediately beneath structures. Project No: 0125-WS24 February 12,2024 Page No: 16 of 18 a . Avoid landscape irrigation and moisture holding plants adjacent to structures. No trees should be planted or present within 15 feet of the foundations. . Thicken or structurally reinforce the structures. We recommend Type l-ll cement for all concrete in contact with the soil on this site. Calcium chloride should not be added. Concrete should not be placed on frost or frozen soil. Concrete must be protected from low temperatures and properly cured. LIMITATIONS Detailed geologic hazards evaluation of any kind was beyond our scope of services, therefore, no warranty of any kind is made regarding geologic hazards present at the site. Evaluation of any kind of existing structures on the site was beyond the scope of services. Recommendations contained in this report are based on our field observations and subsurface explorations, limited laboratory evaluation, and our present knowledge of the proposed construction. lt is possible that soil conditions could vary between or beyond the points explored. lf soil conditions are encountered during construction that differ from those described herein, we should be notified so that we can review and make any supplemental recommendations necessary. lf the scope of the proposed construction, including the proposed loads or structural locations, changes from that described in this report, our recommendations should also be reviewed and revised by AGS. Our Scope of Work for this project did not include research, testing, or assessment relative to past or present contamination of the site by any source. lf such contamination were present, it is very likely that the exploration and testing conducted for this report would not reveal its existence. lf the Owner is concerned about the potential for such contamination, additional studies should be undertaken. We are available to discuss the scope of such studies with you. No tests were performed to detect the existence of mold or other environmental hazards as it was beyond Scope of Work. Local regulations regarding land or facility use, on and off-site conditions, or other factors may change over time, and additional work may be required with the passage of time. Based on the infanr{ar{ r rca nf fho rannrf rrrifhin ^na rraar frnm fha r{afa nf rannr} nranarafinn AllQ marrrrrv rvyvrr Yrrrrrrrr vrr9 Jvsr rrvrrr rrrv vqlv vr rvyvrr lJrvPsrsrrvrrr nvv rrrsJ recommend additionalwork and report updates. Non'compliance with any of these requirements by the client or anyone else will release AGS from any liability resulting from the use of this report by any unauthorized party. Client agrees to defend, indemnify, and hold harmless AGS from any claim or liability associated with such unauthorized use or non-compliance. Project No: 0125-WS24 February 12,2024 Page No: 17 of 18 ln this report, we have presented judgments based partly on our understanding of the proposed construction and partly on the data we have obtained. This report meets professional standards expected for reports of this type in this area. Our company is not responsible for the conclusions, opinions or recommendations made by others based on the data we have presented. Refer to American Society of Foundation Engineers (ASFE) general conditions included in an appendix. This report has been prepared exclusively for the client, its' engineers and subcontractors for the purpose of design and construction of the proposed structure. No other engineer, consultant, or contractor shall be entitled to rely on information, conclusions or recommendations presented in this document without the prior written approval of AGS. We appreciate the opportunity to be of service to you on this project. lf we can provide additional assistance or observation and testing services during design and construction phases, please call us at 1 8882764027. Sincerely, Sam Adettiwar, MS, PE, GE Senior Engineer Attachments Project No: 0125-W524 February 12,2024 Page No: 18 of 18 FIGURES FIGURE 1: SITE LOCATION MAP AMERICAN CEOSERVICES tft ,!Urt0li . rfi !ri*tsgda*{a*(nn+ E m I :@ SITE F 1 1-,-.. .H_I:g-; tiEr] iAspea lree $Cfrtce 'P'" ---"jh; ..1a- 7 i SITE t TION gLOCA I *Q't !!r' ir* *$ LY j .1 otcAEo ?o aRoAooi ' {d.3,Zoorr; 16 Scale:9O28+ I ooort I--r - ----:TI.- -dfg!r REFERENCE: GOOGLE MAPS N USGS TOPOGRAPHIC MAPS AMERICAN CEOSERVICES r{fl J?dJ{!t. @f arw4ri l*l\e**- NOTE: SCHEMATIC PLAN TO SHOWAPPROXIMATE SUBSURFACE EXPLORATION LOCATION ONLY; NOT SURVEYED N LEGEND: 9o=r,cNATES suBSURFAcE EXpLoMTToN LocATroN, By AMERT.AN GEosERVrcES, LLc. , FEBRUAR' 2024 sEE EXPLORATION LOG IN APPENDIX FOR FURTHER DETAILS. REFERENCE: GARFIELD COUNTY COLORADO GIS FIGURE 2: SCHEMATIC SITE PLAN r\.tull:R tLr\t! C 1 .05LRv !L L-5 li"li ?:6..il1:: . r.a N rn:(n9..ri it{r {,tFrV FIGURE 3: GEOLOGIC MAP wvc. , -r .i, ': fi!3: J .i wd', I i I 'A itl I I lrtrl l-)'ii LEGEND tlvl Str*am-channel, floot'l-plain, and low-terruce depositri (Hclocene and late Pleistocene)-Mustlv prxrrlv surted. clast-srrpparterl g:avel in.r srrnt{v or silty nratrix. lnclutJes terrar-ss rtp ln atrortt l2 fl nbove modern rir"er level Sheetwrsh deposits llfol{reene and lrte Plelstocen*}- lfrrhl:lv silty F,rnd, snrdy silt, *ru<l clnvr.v :iill !{i:pr'$it{\'l irr ephrmcral .ilrd itt('rnlitteilt str'irarJr r'.rllc1,s, rrrr g$rtth.r lrillshrpus, ancl in basinal .rreas Young,er terrace alluviunr (late Pleistocenel-futortly fl corly sortcr{, clasl-supptrrted, lrrcallv I'oulds,rv pelrhlu and robbk' gravr'l rn ir $ttfld tttld sill matlir. I)e1:r*siterl ar llhrcial (rutwash. tJnd*rlrcs t('rrnc('s l"l-{5 ft alrovc moricrn strcam ltvcl. Ivla1,' incluilt' finr*graincd overbank clcposit: Marool Fo:malion (Lower Permian? and Upper Perrnsvlvanianl-ll*d hods rrl riiln(l:itcnu, c(rnglomt.ralu, nrrrtl'tonr'. sillston(, .rIil sh.'h,rrrd milror, tlrin bcds il[.g,rJy lir]rc$toiru. lr)p r)f lor[rntidn n(tt elinol(5rl ir quird 1.1 rtg,kl Eagle Valley Formation (Middle PennsylvaIien)-Rudilirh-brolvn, gral', reddish-gray, .rn!i lan siltstrrrq.. slt.llt'. t;rndstortc, livPsum, dnd cnrhon.rte rock: u'hirh ale grad,tdonill belrveel atrd irrtcrtrlrguulg rvitJr llru [ti]rlron li.lflnAlioI lrrd li.rgie V,rlley Evaporit* Collapse dcposits {}leisloer.nr and lete Tertiary}- Hokifi)grnsouji clt'prr*iF of :lightll' trr highly rlrkrm*d bcdr$tk anrl overlling unctr,hrrutetl trt nrorleralely dcfornrerl surfici.rl dcposiis. I-.ncallr, inclurl{s largr int.rct blocks of basalt (Tb) th.rt.rrr. lorvertl lrv roll.rpric. Scveral fllrvr in lhrsc blocks rtere gr-trlrenrically .rnalvzcd. Formeel in rfsf()nsr to difft'n:ntiol r:trllapse resulting from dissr:lutirn uI rurdcrlving rvaprrr:ite PFm Pc OTcd Qtv REFERENCE: U.S. GEOLOGICAL MAPS N OTcd .ts AMERICAN CET)SERYICES tEl,l?r',{nI| " rmdrtrndrr+'ir*rrm FIGURE 4: SOIL SURVEY MAP LEGEND Aspen-Gypsum Area, Colorado, Parts cf Eagle, Garfield, and Fitkin Counties (COGSSI Aspen-Gypsurn Area, Colorado, Parts @ of Eagle, Garfleld, and Pitkin Countlee (co6ss) 106 Brownsto 7,9 15.0VoF{ap Unit llap Unit Hame Acres in AOI 4.9 Percent , stonY sandy loams, 12 to 50 , percent slopes, extrcmely stony Totals for Area of Interest Symbol of AOI 35 35 4Z 55 Ernpedrado loam, 5 to 12 percent slopes Ernpedrado 9 4a/a 7Bla Zo/a 5Va 52,5 ltll}.Oqb 4 rloam, 12 to 25 lpercent slopes ,Fluvaquents,0 ,to 10 percent ,slopes Gypsum land- Gypsiorthlds 'complex, 12 to '65 percent slopes 6.9 1 3. 5.5 10 N REFERENCE: WEB SOIL SURVEY Showalter- Morval complex, 15 to 25 percent lslopes 2r+"8. 47 A,\'TERICAN CLSSIRYICES iq{ z:fj q4i . .Fi*{itr.t{riF{Oiealrfr-"':v FIGURE 5: COLLAPSIBLE SOILS MAP $ - l- gtlloo I ! t.. I) I 'i * strd,locnrroru *l II .t I I I I I I I Legend Co [l a psa b l e_5 o i ls-ut/ itl'r Me e ke n EG-1 4 Eslian {uiind-blown) deposits EG-14 Dune and she,ec sand deposits EG-14 Cretacesus and Tertiary F*rmatinns ::l:,, EG- 1 4 E*,iapor{te ForrFrati ons N REFERENCE COLORADO GEOLOGICAL SURVEY I F Colorado-la ndsli de-inventory-new /.1,i-i - ,i conrFiled landslides-fronr LiDAR-and-.other-mapsI compiled-landslid es-from-24K-maps &a5.J CrsGf, compiled-landelldes-from-48- 1 00K-maps,I compiled-landslid es-from-H8 l 04 li-maps I compiled-l ancislicl esJrom-250K-mapsI 6eologicQ'uddslndex tr * :\ o r-) -{L ,t ;1;t irl,!tr :. : ...1: 11 $gr lna L:" rsl 't.'! a ' : f il -* REFERENCE: COLORADO LANDSLIDES INVENTORY j\\L-egend N A,UT[IT, ICA N CIC-TilIV ICLS dta t'r, + 4'r -.r-'{riirE('d(arlilqd'nV FIGURE 6: LANDSLIDES HMARD FIGURE 7: TYPICAL DETAILSAMERICAN CEOSERVICES 888.276.4027 - rmcrichgslen iKcom NOTESI A. ADDITIONAL REINFORCEMENT, #4 CONTINUOUS BAR, BOTTOM OF FOOTING. B. ADDITIONAL REINFORCEMENT, #4 A1 48" C/C, TOP OF FOOTING.RETAINING WALL DIMENSIONS AND REINFORCEMENT TO BE DONE BY PROJECT STRUCTURAL ENGINEER BASED ON GEOTECHNICAL RECOMMENDATIONS. C, REINFORCEMENT AS PER STRUCTURAL ENGINEER'S DESIGN. AS A MINIMUM, USE #4 NT 48" CIC. CONCRETE FOOTING TO BE DIMENSIONED BY PROJECT STRUCTURAL ENGINEER BASED ON GEOTECHNICAL RECOMMENDATIONS. ADDITIONAL FOOTING REINFORCEMENT DETAIL NEW INTERIOR PART WALL NOTES: D. 4Od NAILS EVERY 24" THROUGH BOTTOM PLATE INTO PRE.DRILLED HOLES OF THE FLOOR PLATE. WALL FINISH WALL BASE BOARD NAILED ONLY TO BASE PRESSURE TREATED 2'X4" BASE PLATE SECURED WITH 3" CONCRETE NAILS OR EQUIVALENT PLATE;TOP IS FREE 3'MIN VOID SPACE SPACER-SAME THICKNESS AS WALL FINISH MATERIAL CONCRETE BASEMENT SLAB "FLOAT' (FLOATING WALL DETAIL) ,k *y"f"l::*H5:tERV rcFs FIGURE 8: DRAINAGE DETAILS FLEXIBLE ADHESIVE EQUIVALENT, 4" ABOVE GROUND; MAINTAIN LEAK-FREE COMPACTED EARTH BACKFILUSOIL CAP (DO NOT USE rF STEM WALL rS DESIGNED AS A RETAINING WALL. IN CASE OF RETAINING WALL, USE FREE-DRAINING CRUSHED ROCK FILL TO AVOID HYSROSTATIC PRESSURE. OVER.EXCAVATION (sEE NOTE B) LEAK-FREE AND ADEQUATE CAPACIry DOWNSPOUTS MINIMUM 3" THICK DECORATIVE GRAVEL, RocK oR ennr uYei AT LEAST 4 FT LONG 20 MIL THICK POLY SHEET LINER AT LEAST 4FT LONG; EXTEND 4' ABOVE GROUND & 36" BELOW GROUND DOWNSPOUT & MOISTURE BARRIER DETAIL EXTEND DOWNSPOUT BEYOND DECORATIVE LAYER, 10H:1V GMDE; WITHOUT CAUSING ADVERSE IMPACT ON ADJACENT PROPERTIES; DISCHARGE ONTO SPLASH BLOCKS. 4 6'MlN l- OFFSET FOR ANY SPRINKLER HEADS; PART CIRCLE SPRAYING AWAY FROM BUILDING SLOPE TO DRAIN AWAY FROM STRUCTURE, 10H:1V (sEE DOWNSPOUT DETATL) FOUNDATION/STEM WALL - POLYETHYLENE FILM GLUED TO FOUNDATION WALL AND EXTENDED BELOWTHE DRAIN AS SHOWN MIRAFI 140 N FILTER FABRIC OR EQUIVALENT f- IzSI-AB-ON-GRADE WITH EXPANSION JOTNTS OR CRAWL€PACE-) 12" MINI 6'MIN FREE.DRAINING CLEAN CRUSHED ROCI(GRAVEL EXCAVATED TRENCH, NEARVERTICALTO 0.5H:1V \-,SUBGRADE, IN-SITU SOIN ,AFF TIA-F A\(oEEr\\,,rErr, PERIMETER OR FOUNDATION DRAIN DETAIL NOTES: A.4-INCH DIAMETER PERFORATED PIPE PLACED 2" ABOVE DRAIN SUBGRADE EMBEDDED IN FREE-DRAINING GMVEL OR CRUSHED ROCK ENVELOPE WITH 2% GRADE TO SUMP PIT OR DISCHARGED TO A SUITABLE RECEPTACLE SUCH THAT ON.SITE AS WELL AS OFF.SITE STABILITY IS NOT ADVERSELY IMPACTED. B. DEPTH BASED ON OPEN HOLE INSPECTION, FOR SHALLOW FOUNDATION OPTION. C. ALL FOUNDATION OR OVER-EXCAVATED SUBGRADES MUST BE INSPECTED AND APPROVED BY A GEOTECHNICAL ENGINEER. APPENDIX B1 Project Number 012s-ws24 Soil Auger and Dynamic Cone Penetrometer (DCP) Ground Elevation See FiguresGeologisVEngineer SMA Date Drilled 02-12-2024 Total Depth of Borehole 5 Feet Borehole Diameter 4 OD lnches Depth to Water Not Encountered cDoJ .9 CL (E Lo Description / Lithology oo CLoo g CL E Go c oo =-9E Fo-o E ao oootr s o .9o = (, CL oo s J o- s JJ s o;o tr .9{.4g CL Eoo t: , d. !-:: ,:, l'.j:',, '. J t- ':,^ SM/ ML SANDY SILT to SILTY SAND, with GRAVEL/COBBLES, medium to fine grain, tan,dry to damp, medium stiff (ALLUVTUM) Completely to partially weathered BEDROCK (POSSTBLY SANDSTONEiMUDSTONE/ STLTSTONE) -2.5- -5.0- 50+ t GM End of Exploration. Groundwater was not encountered during or at the completion of drilling At completion, borehole was backfilled with soil cuttings. Soil/bedrock descriptions are based on subsurface explorations and observation of on-site exposed cuts. ,l- *|:5,}:."$SHtERVT.ES Page 1 82 Project Number 0125-WS24 Soil Auger and Dynamic Cone Penetrometer (DCP) GeologisVEngineer SMA Ground Elevation See Figures Date Drilled 02-12-2024 Total Depth of Borehole 5 Feet Borehole Diameter 4 OD lnches Depth to Water Not Encountered u,oJ o CL(E (9 Description / Lithology oo CLoo g CL E(so tr oo =-9o F o-o s o oootr s o .2o = o CL oo s J o- s JJ s o! at o g CL Eoo sM/ ML SANDY SILT to SILTY SAND, with GRAVEL/COBBLES, medium to fine grain, tan,dry to damp, medium stiff (ALLUVTUM) Completely to partially weathered BEDROCK (POSST BLY SANDSTONE/MU DSTONE/ STLTSTONE) -2.5- trn 50+ l GM End of Exploration. Groundwater was not encountered during or at the completion of drilling. At completion, borehole was backfilled with soil cuttings. Soil/bedrock descriptions are based on subsurface explorations and observation of onsite exposed cuts. AMERICAN GEOSERVICES-tt-*'?8S,U 6,@7 - redtug@re^ic6oB Page 1 V NMTRICNN CEOSERVICES DESCRIPTIVE TERMINOLOGY & SOIL CLASSIFICATION UNIFIED SOIL CLASSIFICATION SYSTEM UNIFIED SOIL CLASSIFIGATION AND SYMBOL CHART LABORATORY CLASSIFICATION CRITERIA COARSE-GRAINED SOILS (more than 50% of material is larger than No. 200 sieve size.) GW Well-graded gravels, gravel-sand mixtures, little or no fines "" = +f sreater than 4; c" = D10 " D6-!!9-0 between 1 and 3GW GP Poorly-graded g ravels, gravel-sand mixtures, little or no fines GP Not meeting all gradation requirements for GW GM Silty g ravels, gravel-sand-silt mixtures GM Atterberg limits below'4" line or P.l. less than 4 GC Clean Gravels than 5% Gravels with fines lhan 12% GRAVELS More than 50% of coarse fraction larger than No. 4 sieve size Clayey gravels, gravel-sand-clay mixtures GC Atterberg limits above "A" line with P.l. greater than 7 Above "A" line with Pl. between 4 and 7 are borderline cases requlring use of dual symbols SW Well-graded sands, gravelly sands little or no fines ", = + sreater than o, "" = -l!LO, ** between I and 3 SW SP Poorly graded sands, gravelly sands, little or no fines SP Not meeting all gradation requirements for GW SM Silty sands, sand-silt mixtures Atterberg line or Pl.SM limits below "A" less than 4 sc Clean Sands than 5% Sands with fines than 1 SANDS 50% or more of coarse fraction smaller than No. 4 sieve size Clayey sands, sand-clay mixtures sc Atterberg limits above "A" line with P.l. greater than 7 Limits plotting in shaded zone with P.l. between 4 andT are borderline cases requiring use of dual symbols. (50% or more of material is smaller than No. 200 sieve size.) FINE-GRAINED SOILS ML Determine percentages of sand and gravel from grain-size curve. Depending on percentage of fines (fraction smaller than No. 200 sieve size), coarse-grained soils are classilied as follows: Less than 5 percent .. More than 12 percent . 5to12percent....... GW Gq SW, SP....,... cM, GC,SM,SC Borderllne cases requiring dual Symbols CL lnorganic silts and very fine sands, rock flour, silty of clayey fine sands or clayey silts with slight plasticity lnorganic clays of low to medium plasticity, gravelly clays, sandy clays, silty clays, lean clays PLASTICIry CHART SILTS AND CLAYS Liquid limit less than 50% OL Organic silts and organlc silty clays of low plasticity MH lnorganic silts, micaceous or dialomaceous fine sandy or silty soils, elastic silts CH lnorganic clays of high plasticity, fat clays SILTS ANN CLAYS Liquid limit 50% or greater OH Organic clays of medium to high plasticity, organic silts HIGHLY ORGANIC sorLs :1-2 PT Peat and other highly organic soils 60 sx50 o-fao u.lctZa^ E20F6J10 o- CH A =u NE: CL MH (OH ML8 )L;L+llt .! 0 10 20 30 40 50 60 70 80 90 100 LTQUlD LrMlr (LL) (%) 0 DESCRIPTIVE TERMINOLOGY & SOIL CLASSIFICATION IELD TESTING DEFINITIONS FOR CONSISTENCY OF COHESIVE sorLs NCY STP (BPF) VERY SOFT EXPLORATION LOGS 0-1 t-4 PP (TSF) LESS THAN 0.25 o.rb - o.sSOFT MEDIUM STIFF STI VERY STIFF HARD DD WD MC PL LL PI oc DRY DENSITY (PCF) WET DENSITY (PCF) MOISTURE CONTENT (%) PLASTTC LrMrT (%) LTQUtD LtMtT (%) PLASTICIry INDEX oRGANtC CONTENT (%) SATU RATION PERCENT (7o) SPECIFIC GRAMry COHESION ANGLE OF INTERNAL FRICTION UNCONFINED COMPRESSION STRENGTH PERCENT PASSING THE #2OO SIEVE CALIFORNIA BEARING RATIO VANE SHEAR POCKET PENETROMETER DRIVE PROBE STANDARD PENETMTION TEST BLOWS PER FOOT (N VALUE) SHELBY TUBE SAMPLE GROUND WATER ROCK QUALIry DESIDNATION TEST PIT BORING HAND AUGER 5-B 9-15 16-30 0.5 - 1.0 1.0 - 2.0 2.0 - 4.0 30+ DIAMETER 0NcHES) >120 12-120 3-12 314-3 1t4 - 3t4 4.75 MM OVER 4,0 RELATIVE DENSIry OF COHESIONLESS SOILS DENSITY s PT (BPF) VERY 0-4 LOOSE 5-10 MEDIUM DENSE 11-30 c o SG QU DENSE VERY DENSE PARTICLE SIZE IDENTIFICATION 31 -50 50+ SIEVE NO.#200 = CBR = VS= PP DP= SPT = BPF = SH= GW RQD = TP= l|= HA= NO.4 10 MEDIUM FINE SILT CLAY .075 MM , 2,OMM : NO.40 .425 MM NO- 200 <0.005 MM FEW GRAINS ARE DISTINGUISHABLE IN THE FIELD OR WITH HAND LENS. GRAINS ARE DISTINGUISHABLE WITH THE AID OF A HAND LENS. MOST GRAINS ARE DISTINGUISHABLE WITH THE NAKED EYE. V'- GRoUNDWATERLEVEUSEEPAGE ENCOUNTERED DURING EXPLOMTION Y - sTATtc 6RSUNDWATER LEVEL WITH DATE MEASURED GRAIN SIZE GRAINED MEDIUM GRAINED COARSE GRAINED <0.04 tNcH 0 tttCH 0.04-0.2 tNcH NAME BOULDER COBBLE GRAVEL COURSE COARSE FINE SAND DESCRIPTIVE TERMINOLOGY & SOIL CLASSIFICATION SPT EXPLORATIONS: STANDARD PENETRATION TESTING IS PERFORMED BY DRIVING A 2 - INCH O.D. SPLIT- SPOON INTO THE UNDISTURBED FORMATION AT THE BOTTOM OF THE BORING WITH REPEATED BLOWS OF A 140 - POUND PIN GUIDED HAMMER FALLTNG 30 tNCHES. NUMBER OF BLOWS (N VALUE) REQUIRED TO DRIVE THE SAMPLER A GIVEN DISTANCE WAS CONSIDERED A MEASURE OF SOIL CONSISTENCY. SH SAMPLING: SHELBY TUBE SAMPLING IS PERFORMED WITH A THIN WALLED SAMPLER PUSHED INTO THE UNDISTURBED SOIL TO SAMPLE 2.0 FEET OF solL. AIR TRACK EXPLORATION: TESTING IS PERFORMED BY MEASURING RATE OF ADVANCEMENT AND SAMPLES ARE RETRIEVED FROM CUTTINGS. HAND AUGUR EXPLORATION TESTING IS PREFORMED USING A 3.25' DIAMETER AUGUR TO ADVANCE INTO THE EARTH AND RETRIEVE SAMPLES. DRIVE PROBE EXPLORATIONS: THIS'RELATIVE DENSIry" EXPLORATION DEVICE IS USED TO DETERMINE THE DISTRIBUTION AND ESTIMATE STRENGTH OF THE SUBSURFACE SOIL AND DECOMPRESSED ROCK UNITS. THE RESISTANCE TO PENETRATION IS MEASURED IN BLOWS-PER-1/2 FOOT OF AN 11-POUND HAMMER WHICH FREE FALLS ROUGHLY 3.5 FEET DRIVING THE 0.5 INCH DIAMETER PIPE INTO THE GROUND. FOR A MORE DETAILED DESCRIPTION OF THIS GEOTECHNICAL EXPLORATION METHOD, THE SLOPE STABILIry REFERENCE GUIDE FOR NATIONAL FORESTS IN THE UNITED STATES, VOLUME I, UNITED STATES DEPARTMENT OF AGRICULTURE, EM-7170-13, AUGUST 1994, P. 317- 321. CPT EXPLOMTION: CONE PENETROMETER EXPLORATIONS CONSIST OF PUSHING A PROBE CONE INTO THE EARTH USING THE REACTION OF A 2O-TON TRUCK, THE coNE RESISTANCE (aC) AND SLEEVE FRTCTION (FS) ARE MEASURED AS THE PROBE WAS PUSHED INTO THE EARTH. THE VALUES OF QC AND FS (tN TSF) ARE NOTED AS THE LOCALTZED INDEX OF SOIL STRENGTH. SUBROUNDED COARSE GRAINED ROUNDED ANGULARTTY OF SUBANGULNR SIMILAR TO ANGULAR BUT HAVE ROUNDED EDGES. PARTICLES HAVE NEARLY PLANE SIDES BUT HAVE WELL ROUNDED CORNERS AND EDGES. COARSE GRAINED PARTICLES HAVE SMOOTHLY CURVED SIDES AND NO EDGES. MOIST WET WEATHERED STATE SOIL MOISTURE MODIFIER DRY ABSENCE OF MOISTURE; DUSTY, DRY TO TOUCH DAMP BUT NO VISIBLE WATER VISIBLE FREE WATER NO VISIBLE SIGN OF ROCK MATERIAL WEATHERING; PERHAPS SLIGHT DISCOLORATION IN MAJOR DISCONTINUIry SURFACES. INDICATES WEATHERING OF ROCK MATERIAL AND DISCONTINUITY SURFACES. ALL THE ROCK MATERIAL MAY BE DISCOLORED BY WEATHERING AND MAY BE SOMEWHAT WEAKER EXTERNALLY THAN ITS FRESH CONDITION. rnesH SLIGHTLY WEATHERED MODEMTELY WEATHERED HIGHLY WEATHERED COMPLETELY WEATHERED LESS THAN HALF OF THE ROCK MATERIAL IS DECOMPOSED AND/OR DISINTEGRATED TO SOIL. FRESH OR DISCOLORED ROCK IS PRESENT EITHER AS A CONTINUOUS FMMEWORK OR NS CORE STONES. MORE THAN ANIT OT THE ROCK MATERIAL IS DECOMPOSED AND/OR DISINTEGRATED TO SOIL. FRESH OR DISCOLORED ROCK IS PRESENT EITHER AS DISCONTINUOUS FMMEWORK OR AS CORE STONE. ALL ROCK MATERIAL IS DECOMPOSED AND/OR DISINTEGRATED TO SOIL. THE ORIGINAL MASS STRUCTURE IS STILL LARGELY INTACT. RESIDUAL SOIL ALL ROCK MATERIAL IS CONVERTED TO SOIL, THE MASS STRUCTURE AND MATERIAL FABRIC IS DESTROYED. THERE IS A LARGE CHANGE IN VOLUME, BUT THE SOIL HAS NOT BEEN SIGNIFICANTLY TRANSPORTED. Map Unit Description: Showalter-Morval complex, 15 to 25 percent slopes*-Aspen-Gypsum Area, Colorado, Parts of Eagle, Garfield, and Pitkin Counties Aspen-Gypsum Area, Golorado, Parts of Eagle, Garfield, and Pitkin Gounties 95-Showalter-Morval complex, 15 to 25 percent slopes Map Unit Setting National map unit symbol: iqTv Elevation: 7,000 to 8,500 feet Mean annual precipitation: 14 to 16 inches Mean annual air temperature: 42 to 44 degrees F Frost-free period: 80 to 90 days Farmland classification: Not prime farmland Map Unit Composition Showalter and similar soils: 45 percent Morual and similar so/s; 35 percent Minor components: 20 percent Estimates are based on obseruations, descriptions, and transects of the mapunit. Description of Showalter Setting Landform: Alluvial fans, terraces, valley sides Landform position (three-dimensional) : Tread Down-slope shape : Linear Across-s/op e sh ape : Li near Parent material: Alluvium derived from basalt Typicalprofile Hl - 0 to 8 inches: very stony loam H2 - 8 to 39 inches.' very cobbly clay H3 - 39 to 60 inches.' very cobbly clay loam Properties and qualities S/ope; 15 to 25 percent Depth to restrictive feature: More than 80 inches Drainage c/ass; Well drained Runoff class; Very high Capactty of the most limiting layer to transmit water (Ksat): Moderately low to moderately high (0.06 to 0.20 in/hr) Depth to water table: More than 80 inches Frequency of flooding: None Frequency of ponding: None Calciu m carbonate, maxim um content: 1 0 percent Available water supply, 0 to 60 inches: Low (about 5.5 inches) lnterpretive groups Land capability classification (inigated): None specified Land capability classification (nonirrigated): 7s Hydrologic Soil Group: C Ecologicalslte; R048AY303CO - Loamy Slopes L[iDA - , Natural Resources :Conservation Service Web Soil Survey National Cooperative Soil Survey 2t1312024 Page 1 of 2 Map Unit Description: Showalter-Morval complex, 15 to 25 percent slopes--Aspen-Gypsum Area, Colorado, Parts of Eagle, Garfield, and Pitkin Counties Other vegetative classificafion: LOAMY SLOPES (null31) Hydric sol/ ratngj No Description of Morval Settlng Landform: Alluvial fans Down-slope shape: Linear Across-s/ope shape : Linear Parent material: Alluvium derived from basalt Typical profile H1 -0to7 inches: loam H2 - 7 to 19 inches: clay loam H3 - 19 to 60 inches.' loam Properties and qualities S/ope; 15 to 25 percent Depth to restrictive feature: More than 80 inches Drainage c/ass; Well drained Runoff class; Very high Capacity of the most limiting layer to transmit water (Ksat): Moderately high (0.20 to 0.60 in/hr) Depth to water table.' More than 80 inches Frequency of flooding: None Freque ncy of pondrng; None Calciu m carbonate, maximu m content: 25 percent Maximum salinity: Nonsaline to slightly saline (0.0 to 4.0 mmhos/cm) Available water supply, 0 to 60 inches: High (about 9.3 inches) lnterpretive groups Land capability classification (inigated): None specified Land capability classification (nonirrigated): 6e Hydrologic Soil Group: C Ecologicalslfe; R048AY292CO - Deep Loam Other vegetative classificaflon; DEEP LOAM (null_11) Hydric so/ rafing; No Minor Components Other soils Percent of map unit:20 percent Hydric so/ rafing: No Data Source lnformation Soil Survey Area: Aspen-Gypsum Area, Colorado, Parts of Eagle, Garfield, and Pitkin Counties Survey Area Data: Version 14, Aug 23,2023 I,[iDA - Natural Resources Conservation Service Web Soil Survey National Cooperative Soil Survey 2t13t2024 Page2 of 2 Map Unit Description: Gypsum land-Gypsiorthids complex, 12 to 65 percent slopes--Aspen- Gypsum Area, Colorado, Parts of Eagle, Garfield, and Pitkin Counties Aspen-Gypsum Area, Colorado, Parts of Eagle, Garfield, and Pitkin Gounties 55-Gypsum land-Gypsiorthids complex, 12 to 65 percent slopes Map Unit Sefting National map unit symbol: jq6f Elevation: 5,990 to 9,820 feet Mean annual precipitation: 10 to 15 inches Mean annual air temperature: 39 to 46 degrees F Frost-free period: 80 to 105 days Farmland classification; Not prime farmland Map Unit Gomposition Gypsum land:65 percent Gypsiorthids and similar soils: 2O percent Minor components: 15 percent Esfmafes are based on obseruations, descriptions, and transects of the mapunit. Description of Gypsum Land Typicalprofile Hl - 0 to 60 inches; gypsiferous material Properties and qualities S/ope; 12 to 65 percent Depth to restrictive feature:0 inches to paralithic bedrock Runoffclass; Very high Capacity of the most limiting layer to transmit water (Ksat); Very low (0.00 to 0.00 in/hr) Maximum salinity: Moderately saline to strongly saline (8.0 to 32.0 mmhos/cm) Available water supply, 0 to 60 inches: Very low (about 0.0 inches) Interpretive groups Land capability classification (irngated) : None specified Land capability classification (nonirrigated): 8s Hydric so/ rafing; No Description of Gypsiorthids Setting Landform : Mountains, drainageways, hills Landform position (two-dimensional) : Shoulder La ndform position (th ree-di me n si on al) : Mountainfl ank, side slope Down-slope shape: Linear Across-s/op e s h ape : Li near Parent material: Mixed colluvium and/or mixed residuum I.TiI}A - Natural Resources ,Conseryation Service Web Soil Survey National Cooperative Soil Survey 2t13t2024 Page 1 of2 Map Unit Description: Gypsum land-Gypsiorthids complex, 12 to 65 percent slopes--Aspen- Gypsum Area, Colorado, Parts of Eagle, Garfield, and Pitkin Counties Typical profile Hl - 0 to I inches: fine sandy loam H2 - 8 to 23 inches; fine sandy loam H3 - 23 to 39 inches; fine sandy loam H4 - 39 to 43 inches.' weathered bedrock Properties and qualities S/ope; 12 to 50 percent Depth to restrictive feature: 10 to 40 inches to paralithic bedrock Drainage c/ass; Well drained Runoff class: Medium Capacity of the most limiting layer to transmit water (Ksat): Moderately low to high (0.06 to 2.00 inihr) Depth to water table: More than 80 inches Frequency of floodrng; None Frequency of pondrng: None Calcium carbonate, maximum content: 1 0 percent Gypsum, maximum content: 1 2 percent Maximum salinity: Slightly saline to moderately saline (4.0 to 8.0 mmhos/cm) Available water supply, 0 to 60 inches: Low (about 5.5 inches) lnterpretive groups Land capability classification (irrigated) : None speclfled Land capability cl assification (noni rrigated) : 8s Hydrologic Soil Group: B Hydric so/ rafing; No Minor Components Other soils Percent of map unit: 15 percent Hydric so/ rafing; No Data Source Information Soil Survey Area: Aspen-Gypsum Area, Colorado, Parts of Eagle, Garfield, and Pitkin Counties Survey Area Data: Version 14, Aug 23,2023 t,EiDA--Natural Resources Gonservation Service Web Soil Survey National Gooperative Soil Survey 211312024 Page 2 ol 2 IMPORTANT INFORMATION ABOUT YOUR GEOTECHNICAL ENGINEERING REPORT As,the client of a consulting geotechnical engineer, you should know that site subsurface conditions cause more construction problems than any other factor. ASFE/the Association of Engineering Firms Practicing in the Geosciences offers the following suggestions and observations to help you manage your risks. A GEOTECHNICAL ENG.NEERING REPORT IS BASED ON A UNIQUE SET OF PROJECT. SPECIFIC FACTORS Your geotechnical engineering report is based on a subsurface exploration plan designed to consider a unique set of project-specific factors. These factors typically include: the general nature of the structure involved, its size, and conflguration; the location of the structure on the site; other improvements, such asi access roads, parking lots, arid underground utilities; and the additional risk created by scope- of-service limitations imposed by the client. To help avoid costly problems, ask your geotechnical engineer to evaluate how factors that change subsequent to the date of the report may affect the report's recommendations. l Unless your geotechnical engineer indicates otherwise, do not use your geotechnical engineering report: MOST GEOTECHNICAL FINDINGS ARE PROFESSIONAL JUDGMENTS Site exploration identifies actual subsurface conditions only at those points where samples are taken. The data were extrapolated by your geotechnical engineer who then applied judgment to render an opinion about overall subsurface conditions. The actual interface between materials may be far more gradual or abrupt than your report indicates, Actual conditions in areas not sampled may differ from those predicted in your report. While nothing can be done to prevent such situations. you and your geotechnical engineer can work together to help minimize their impact. Retaining your geotechnical engineer to observe construction can be particularly beneficial in this respect. r when the nature of the proposed structure is changed. for example, if an office building will be erected instead of a parking garage, or a refrigerated warehouse will be built instead of an unrefrigerated one; o when the size, elevation. or configuration of the proposed structure is altered; o when the location or orientation of the proposed structure is modified; o when there is a change of ownership; or .for application to an adjacent site. Geotechnical enqineers cannot accept resoonsibilitv for-oroblems that mav occur if thev are'not condulted after factors considered in their report's development have changed. A REPORT'S RECOMMENDATIONS CAN ONLY BE PRELIMINARY The construction recommendations included in your geotechnical engineer's report are preliminary, because they must be based on the assumption that conditions revealed through selective exploratory sampling are indicative of actual conditions throughout a site. Because actual subsurface conditions can be discerned only during earthwork, you should retain your geo- technical engineer to observe actual conditions and to finalize recommendations. Only the geotechnical engineer who prepared the report is fully familiar with the background information needed to determine whether or not the report's recommendations are valid and whether or not the contractor is abiding by applicable recommendations. The geotechnical engineer who developed your report cannot assume responsibility or liability for the adequacy of the report's recommendations if another party is retained to observe construction. SUBSURFACE CONDITIONS CAN CHANGE A geotechnical engineering report is based on condi- tions that existed at the time of subsurface exploration. Do not base construction decisions on a geotechnical engineering report whose adequacy may have been affected by time. Speak with your geotechnical consult- ant to learn if additional tests are advisable before construction starts. Note, too, that additional tests may be required when subsurface conditions are affected by construction operations at or adjacent to the site, or by natural events such as floods, earthquakes, or ground water fluctuations. Keep your geotechnical consultant apprised of any such events. GEOTECHNICAL SERVICES ARE PERFORMED FOR SPECIFIC PURPOSES AND PERSONS Consulting geotechnical engineers prepare reports to meet the specific needs of specific individuals. A report prepared for a civil engineer may not be adequate for a construction contractor or even another civil engineer. Unless indicated otherwise, your geotechnical engineer prepared your report expressly for you and expressly for purposes you indicated. No one other than you should apply this report for its intended purpose without first conferring with the geotechnical engineer. No party should apply this report for any purpose other than that originally contemplated without first conferring with the geotechnical engineer. GEOENVIRONMENTAL CONCERNS ARE NOT AT ISSUE Your geotechnical engineering report is not likely to relate any findings, conclusions, or recommendations about the potential for hazardous materials existing at the site. The equipment, techniques, and personnel used to perform a geoenvironmental exploration differ substantially from those applied in geotechnical engineering. Contamination can create major risks. lf you have no information about the potential for your site being contaminated. you are advised to speak with your geotechnical consultant for information relating to geoenvironmental issues. A GEOTECHNICAL ENGINEERING REPORT IS SUBJECT TO MISINTERPRETATION Costly problems can occur when other design profes- sionals develop their plans based on misinterpretations of a geotechnical engineering report. To help avoid misinterpretations, retain your geotechnical engineer to work with other project design professionals who are affected by the geotechnical report. Have your geotechnical engineer explain report implications to design professionals affected by them. and then review those design professionals' plans and specifications to see how they have incorporated geotechnical factors. Although certain other design professionals may be fam- iliar with geotechnical concerns, none knows 'as much about them as a competent geotechnical engineer. BORING LOGS SHOULD NOT BE SEPARATED FROM THE REPORT Geotechnical engineers develop final boring logs based upon their interpretation of the field logs (assembled by site personnel) and laboratory evaluation of field samples. Geotechnical engineers customarily include only final boring logs in their reports. Final boring logs should not under any circumstances be redrawn for inclusion in architectural or other design drawings. because drafters may commit errors or omissions in the transfer process. Although photographic reproduction eliminates this problem, it does nothing to minimize the possibility of contractors misinterpreting the logs during bid preparation. When this occurs. delays. disputes. and unanticipated costs ara the alltoo-frequent result. To minimize the likelihood of boring log misinterpretation, give contractors ready access to the complete geotechnical engineering report prepared or authorized for their use. (lf access is provided only to the report prepared for you, you shouicj acivise coniraciors of ihe repori's limitations. assuming that a contractor was not one of the specific persons for whom the report was prepared and that developing construction cost estimates was not one of the specific purposes for which it was prepared. ln other words. while a contractor may gain important knowledge from a report prepared for another party, the contractor would be well-advised to discuss the report with your geotechnical engineer and to perform the additional or alternative work that the contractor believes may be needed to obtain the data specifically appropriate for construction cost estimating purposes.) Some clients believe that it is unwise or unnecessary to give contractors access to their geo- technical engineering reports because they hold the mistaken impression that simply disclaiming responsibility for the accuracy of subsurface information always insulates them from attendant liability. Providing the best available information to contractors helps prevent costly construction problems. lt also helps reduce the adversarial ' attitudes that can aggravate problems to disproportionate scale. READ RESPONSIBILITY CLAUSES CLOSELY Because geotechnical engineering is based extensively on judgment and opinion, it is far less exact than other design disciplines. This situation has resulted in wholly unwarranted claims being lodged against geotechnical engineers. To help preverrt tlris problerrt, geoteclrnical engineers have developed a number of clauses for use in their l contracts, reports, and other documents. Responsibility clauses are not exculpatory clauses designed to transfer geotechnical engineers' liabilities to other parties. lnstead, they are definitive clauses that identify where geotechnioal engineers' responsibilities begin and end. Their use helps all parties involved recognize their individual responsibilities and take appropriate action. Some of these definitive clauses are likely to appear in your geotechnical engineering report. Read them closely. Your geotechnical engineer will be pleased to give full and frank answers to any questions. RELY ON THE GEOTECHNICAL ENGINEER FOR ADDITIONAL ASSISTANCE Most ASFE-member consulting geotechnical engineering firms are familiar with a variety of techniques and approaches that can be used to help reduce risks fdr all parties to a constructioh project, from design through construction. Speak with your geotechnical engineer not only about geoiechnicai issues, bui oihers as weii, io iearn about approaches that may be of genuine benefit. You may also wish to obtain certain ASFE publications. Contact a member of ASFE of ASFE for a complimentary directory of ASFE publications. ASFE 8811 Colesville Road/Suite G106/Silver Spring, MD 20910 Telephone: 30 1 I 565-27 33 Facsim i le : 30 1 I 589-20 17 Subsurfqce Explorotions Soil Tesling Eorlhwork nE .RudGMe j ' '-+";".e' t 'a; i l ! I i I t: E e srgn !,:, -iiiii"' r0veme nl Design Droinoge Evoluulions Groundwoter Sludies Environmentul Assels Building Assessmenls 1 I' AMERICAN GEOSERYI CES. COM