Limited Geotechnical Engineering Evaluation Classroom Additions Albany County Campus Laramie, Wyoming

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1 Limited Geotechnical Engineering Evaluation Classroom Additions Albany County Campus 2300 Missile Drive, Cheyenne, Wyoming Phone

3 Limited Geotechnical Engineering Evaluation Classroom Additions Albany County Campus PREPARED FOR: Laramie County Community College Mr. Tim Macnamara 1400 College Drive Cheyenne, Wyoming PREPARED BY: STRATA, A Professional Services Corporation 2300 Missile Drive Cheyenne, Wyoming Telephone (307) January 5, 2017

4 TABLE OF CONTENTS Page INTRODUCTION... 1 Project understanding... 2 Existing Conditions... 2 Proposed Construction... 2 FIELD EXPLORATION... 2 LABORATORY TESTING... 3 SUBSURFACE CONDITIONS... 3 GEOTECHNICAL OPINIONS AND RECOMMENDATIONS... 4 Drilled Pier Foundation Design... 5 EVALUATION LIMITATIONS... 5 Plate 1 Appendix A Appendix B Location of Exploratory Borings Exploratory Boring Logs USCS Information Laboratory Test Results by Strata, A Professional Services Corporation. All rights reserved.

5 Limited Geotechnical Engineering Evaluation Classroom Additions Albany County Campus INTRODUCTION STRATA, A Professional Services Corporation (STRATA) is pleased to provide our limited geotechnical engineering evaluation for the classroom additions to be constructed onto the Albany County Campus facility in. The purpose of this evaluation is to assess the subsurface conditions at the two classroom areas and to prepare geotechnical engineering opinions and recommendations that may be used for planning, design and construction of the new classroom foundations that are adjacent to the existing building. The scope of this report is intended solely to address concerns relative to the new classroom addition foundations that are immediately adjacent to the existing building and within the stress influence zone of the existing shallow spread footings supported at frost depth within the overburden soils. The scope of this report specifically excludes geotechnical information relative to other aspects of the project such as, the use of spread footings in other areas of the new additions, floor slabs, drainage and earthworks. We understand that geotechnical information relative to the use of spread footings, slabs on-grade and other aspects of the project is presented in the original geotechnical report prepared by Terracon Consultants for the initial building development; and that the project design team intends to use the original report to the extent possible for the current project. This report must be read, understood and implemented in its entirety. Report portions cannot be relied upon individually without the supporting text of remaining sections, appendices and figures. Our opinion is that the success of the proposed construction will depend on following the report recommendations, good construction practices, and providing the necessary construction monitoring, testing, and consultation to verify that work has been completed as recommended. We accomplished this evaluation referencing our proposal dated November 11, To accomplish our evaluation, STRATA performed the following services: 1. One exploratory boring was drilled to an approximate depth of 19 feet within the eastern classroom addition area. 2. The soils encountered were visually described, classified, and logged referencing the Unified Soil Classification System (USCS). The soil and rock samples were returned to our laboratory for additional visual assessment and testing by Strata, A Professional Services Corporation. All rights reserved.

6 Classroom Additions Albany County Campus File: WY16316A Page 2 3. Laboratory testing was performed in general accordance with ASTM procedures including in-situ moisture, Atterberg limits, grain-size analysis and consolidation. We utilized these laboratory results to help characterize the soil and rock properties for use in our engineering analyses. 4. Engineering analyses were performed in order to provide geotechnical design and construction recommendations for the new foundations adjacent to the existing building. PROJECT UNDERSTANDING Existing Conditions The project is located on the Albany County Campus at 1125 Boulder Drive in Laramie, Wyoming. The Campus site is situated on the east side of Boulder Drive, south of the Farm Bureau and east of the Laramie Rec Center. The existing building is a single-story, metal framed structure with masonry veneer and slab on-grade floor. The structure is comprised of two square buildings that are connected at the corners with a tall steel-frame structure with glass atrium area. The existing building is supported on spread footing foundations that presumably bear at a minimum 42-inch frost depth. The overall site slopes down to the west at an approximate 2 percent grade. Proposed Construction The new classroom additions will be situated on the southern corners of each of the two main buildings and within areas that are currently paved patios. The new structures will each be approximately 40 feet by 45 feet and will utilize similar steel framing and masonry veneer as the existing buildings. Elevation Structural Design reports the maximum column and wall loads are 16 kips and 1.4 kips per linear foot, respectively. Tolerable settlement criteria for the additions have not been specifically defined, although in our conversations with the design team it was agreed that differential movements between the existing and new structures should be minimal. We assume that differential movements on the order of ½-inch or less are acceptable. FIELD EXPLORATION STRATA drilled a single exploratory boring within the proposed eastern classroom addition on December 14, The boring was advanced to an approximate depth of 19 feet. The location of the boring is presented on Plate 1 and the log of boring is presented in Appendix A. The boring was staked in the field by Strata personnel and the ground surface elevation at the boring was determined based on a survey referencing the finished floor elevation of the existing building by Strata, A Professional Services Corporation. All rights reserved.

7 Classroom Additions Albany County Campus File: WY16316A Page 3 STRATA advanced the boring using a CME-55 track-mounted drill rig equipped with 4- inch diameter solid-stem augers. An experienced geotechnical engineer logged and visually classified the soil encountered in the boring referencing the Unified Soil Classification System (USCS). Soil samples were obtained within the boring via 2-inch and 2.5-inch outside diameter split-barrel samplers driven with a 140-pound automatic hammer falling 30 inches. The N values presented on the logs have not been corrected for sampler size, overburden stress or hammer efficiency. Sampling was performed in general conformance with ASTM D1586 and samples were collected at selected depth intervals as indicated on the logs. LABORATORY TESTING The soil samples collected in the field were returned to our laboratory for further classification and testing in accordance with ASTM procedures. We completed the following laboratory testing, the results of which are presented on the boring logs and in Appendix B: Natural moisture content Sieve analyses Plasticity indices Consolidation SUBSURFACE CONDITIONS The soil conditions encountered in the boring generally consist of unconsolidated sand, silt and clay overlying siltstone bedrock. A more specific discussion of each stratum encountered is presented below: Silty clayey sand (SC-SM) Below a thin surficial layer of landscaping gravel, medium dense, reddish-brown silty clayey sand extended to an approximate depth of 3 feet. The sand fraction of the soil consisted of fine to medium grained particles and the silty clay fraction exhibited low plasticity. Poorly graded sand with silt (SP-SM) Below the silty clayey sand layer, reddish-brown poorly graded sand with silt extended to an approximate depth of 4.5 feet. The sand fraction varied from fine to medium grained and the relative density of the soil was loose. Silty sand (SM) Below the poorly graded sand layer, medium dense, reddish brown, silty sand extended to an approximate depth of 8 feet. This soil is effectively a residual siltstone/sandstone material that is weathered to the point that little to no structure remains. The sand fraction was primarily of fine grained particle size and the silt fraction was non-plastic Siltstone bedrock Below the silty sand layer, moderately hard, reddish-brown siltstone extended to the maximum depth of exploration by Strata, A Professional Services Corporation. All rights reserved.

8 Classroom Additions Albany County Campus File: WY16316A Page 4 Groundwater Groundwater was not encountered at the time of drilling. Based on the moisture content data for the various material within the foundation influence zone, we do not anticipate significant effects associated with groundwater. However, numerous factors can contribute to the presence or fluctuation of groundwater levels. The evaluation of these factors is beyond the scope of this study. GEOTECHNICAL OPINIONS AND RECOMMENDATIONS The primary concern for the support of the new building columns is differential movements between the existing and new foundations. The existing spread footing foundations supported on soil are assumed to have reached a condition of equilibrium and for the purpose of this study can be taken to be stable with no expected additional movements. On the other hand, any new footings can be expected to settle to some extent due to the addition of foundation loads. For practical purposes, it can be taken that the total settlements of the new foundations will define the differential movements between the new and existing foundations. In addition, new spread footings can impose additional stresses on the adjacent existing footings, resulting in potential additional movements of the existing footings. In order to maintain strain compatibility between the existing footings and adjacent new footings, it is necessary to limit the potential settlement of the new footings to a negligible value. For this reason, and based on the conditions encountered and our knowledge of the site, it is our opinion that the limited column supports for the classroom additions that are adjacent to the existing building should be supported on the siltstone bedrock. There are at least three feasible alternative foundation systems that can provide adequate support, including drilled piers, helical piers and direct footing embedment in the siltstone. Based on our initial conversations with Mr. Ken Tobin and Mr. Jeremy Tuck of the design team, we understand that conventional drilled piers are preferred due to availability of local contractors and cost. Therefore, design and construction recommendations for drilled piers are presented in the following sections. The recommendations presented reflect our understanding of the proposed classroom addition locations, configuration, loading conditions, existing topography, existing geotechnical data, and subsurface conditions as encountered. Subsurface conditions may vary from what was observed during our subsurface evaluation and the extent of this variation is unknown and will not be known until construction, and may impact foundation design and construction cost and/or schedule by Strata, A Professional Services Corporation. All rights reserved.

9 Classroom Additions Albany County Campus File: WY16316A Page 5 Drilled Pier Foundation Design The following design and construction recommendations should be observed for drilled pier foundation systems for the proposed classroom structure supports located adjacent to the existing building foundations. 1. Design straight shaft drilled piers using a maximum allowable end bearing pressure of 9,000 psf. 2. Piers must penetrate the competent siltstone bedrock a minimum of one foot. We anticipate pier lengths may vary from approximately 8 to 10 feet. Provide a contingency in the pier schedule to allow for additional length to be added in the field. Reinforce the full length of drilled piers as required per ACI. 3. Design piers with a minimum diameter of 16 inches to facilitate proper cleaning, observation of the pier hole, and concrete placement. 4. Use a concrete with a fluid mix with a slump range of 6 to 8 inches so that it will fill voids between reinforcing steel and the pier hole. Construct individual piers and place concrete immediately after the excavation is performed. 5. We anticipate only single piers will be used at each column location. However, if multiple piers are used then capacity reduction factors and minimum pier spacing must be included in the pier design. We can provide these values if requested. 6. We anticipate the use of a tremie and concrete pump to place the pier concrete. Due to anticipated raveling and sloughing of the overburden sands, pier concrete quantities may exceed calculated neat-line volumes. EVALUATION LIMITATIONS This geotechnical engineering evaluation has been prepared to assist the planning, design and construction of the new classroom column foundations adjacent to existing building. Our services consist of professional opinions and recommendations made in accordance with generally accepted geotechnical engineering principles and practices as they exist in Wyoming at the time of this report. The geotechnical recommendations provided herein are based on the premise that an adequate program of tests and observations will be conducted during construction in order to document compliance with our recommendations and to confirm conditions exposed during subgrade preparations. Further, the method of exploration used allows observation of a relatively small sample of the subsurface conditions at the site. Variations may exist beyond the exploration locations. These variations would not be apparent until construction. Where such variation does by Strata, A Professional Services Corporation. All rights reserved.

10 Classroom Additions Albany County Campus File: WY16316A Page 6 exist, it may affect the options and recommendations presented in this report, as well as construction timing and costs by Strata, A Professional Services Corporation. All rights reserved.

$12/28/2016 8:31:01 AM - V:\STRATA - CHEYENNE PROJECTS\L\LARAMIE COMMUNITY COLLEGE\WY16316A ALBANY COUNTY CAMPUS\DRAFTING\WY16316A PLATE 1.$ COMPRISES A PORTION OF STRATA'S REPORT AND THE TEXT OF THE REPORT CONTAINS ESSENTIAL INFORMATION: BEFORE UTILIZING THIS PLAN FOR ANY PURPOSE WHATSOEVER, THE REPORT SHOULD BE READ COMPLETELY.

COMPRISES A PORTION OF STRATA'S REPORT AND THE TEXT OF THE REPORT CONTAINS ESSENTIAL INFORMATION: BEFORE UTILIZING THIS PLAN FOR ANY PURPOSE WHATSOEVER, THE REPORT SHOULD BE READ COMPLETELY.

THESE LOCATIONS AND INFORMATION WERE ADDED TO EXISTING PLANS OF THE SITE PREVIOUSLY PREPARED BY OTHERS AND NO CHECK OF ACCURACY, CURRENCY, APPROPRIATENESS, ETC.

11 12/28/2016 8:31:01 AM - V:\STRATA - CHEYENNE PROJECTS\L\LARAMIE COMMUNITY COLLEGE\WY16316A ALBANY COUNTY CAMPUS\DRAFTING\WY16316A PLATE 1.DWG - MARIE TAYLOR BOULDER DRIVE BASE IMAGE CREATED FROM: GOOGLE EARTH (Dated ) LEGEND: B-1 B-1 EXPLORATORY BORING DRILLED NOVEMBER 12, 2016 LARAMIE GRAND AVE (HWY 80) PROJECT SITE THIS PLAN COMPRISES A PORTION OF STRATA'S REPORT AND THE TEXT OF THE REPORT CONTAINS ESSENTIAL INFORMATION: BEFORE UTILIZING THIS PLAN FOR ANY PURPOSE WHATSOEVER, THE REPORT SHOULD BE READ COMPLETELY. THIS PLAN IS INTENDED TO HELP VISUALIZE THE INFORMATION PROVIDED IN THE REPORT. THESE LOCATIONS AND INFORMATION WERE ADDED TO EXISTING PLANS OF THE SITE PREVIOUSLY PREPARED BY OTHERS AND NO CHECK OF ACCURACY, CURRENCY, APPROPRIATENESS, ETC., OF INFORMATION PROVIDED BY OTHERS WAS PERFORMED, SINCE SUCH CHECKS WERE NOT PART OF STRATA'S SCOPE OF SERVICES Missile Drive Cheyenne, Wyoming PHONE: CLIENT: Laramie County Community College Albany County Campus Classroom Additions EXPLORATION LOCATION I-80 VICINITY MAP NOT TO SCALE Project No.: Date: Drawn By: N SCALE IN FEET (APPROXIMATE) PLATE Copyright: STRATA WY16316A December MAT

12 APPENDIX A Exploratory Boring Log USCS Information

$STRATA BOREHOLE - STRATA.GDT - 1/5/17 14:06 - X:\STRATA - CHEYENNE PROJECTS\L\LARAMIE COUNTY COMMUNITY COLLEGE\WY16316A ALBANY COUNTY CAMPUS\ELECTRONIC LOGS\LCCC CLASSROOM ADDITION.$

13 STRATA BOREHOLE - STRATA.GDT - 1/5/17 14:06 - X:\STRATA - CHEYENNE PROJECTS\L\LARAMIE COUNTY COMMUNITY COLLEGE\WY16316A ALBANY COUNTY CAMPUS\ELECTRONIC LOGS\LCCC CLASSROOM ADDITION.GPJ USCS Description LANDSCAPING ROCK SILTY CLAYEY SAND, (SC-SM) reddish brown, fine to medium sand, medium dense, moist, trace gravel POORLY GRADED SAND WITH SILT, (SP-SM) reddish brown, fine to medium sand, loose, moist, trace gravel SILTY SAND, (SM) light brown, fine sand, medium dense, moist, highly weathered residual siltstone, varies to sandy silt SILTSTONE, reddish brown, medium hard, damp, trace clay Elevation based on finish floor of existing building = ' Borehole Terminated at 19.2 Feet. Elevation Symbol Sample Type Project Name: Classroom Additions - Albany County Campus SPT Blows Per 6 Inches /6.0" /6.0" /2.0" /2.0" 100+ Dry Density (pcf) TEST RESULTS Pocket Penetrometer, TSF % Passing No. 200 Sieve PL MC LL non-plastic non-plastic BORING LOG Project #: WY16316A Client: Laramie County Community College 1 Date Drilled: 12/22/2016 Drill Rig: CME 55 Borehole Dia.: 4" SFA Groundwater Depth: N.E. Depth (ft) SC- SM SP- SM SM Drilled By: Strategic Expl. SPT - N Logged By: T. Olson SPT, N-Value Remarks Note: BGS = Below Ground Surface Sheet 1 Of 1

14 MAJOR DIVISIONS GRAPH SYMBOL LETTER SYMBOL TYPICAL NAMES COARSE GRAINED SOILS FINE GRAINED SOILS GRAVELS SANDS CLEAN GRAVELS GRAVELS WITH FINES CLEAN SANDS SANDS WITH FINES SILTS AND CLAYS LIQUID LIMIT LESS THAN 50% SILTS AND CLAYS LIQUID LIMIT GREATER THAN 50% GW GP GM GC SW SP SM SC ML CL OL MH CH OH PT Well-Graded Gravel, Gravel-Sand Mixtures. Poorly-Graded Gravel, Gravel-Sand Mixtures. Silty Gravel, Gravel- Sand-Silt Mixtures. Clayey Gravel, Gravel- Sand-Clay Mixtures. Well-Graded Sand, Gravelly Sand. Poorly-Graded Sand, Gravelly Sand. Silty Sand, Sand-Silt Mixtures. Clayey Sand, Sand-Clay Mixtures. Inorganic Silt, Sandy or Clayey Silt. Inorganic Clay of Low to Medium Plasticity, Sandy or Silty Clay. Organic Silt and Clay of Low Plasticity. Inorganic Silt, Micaceous Silt, Plastic Silt. Inorganic Clay of High Plasticity, Fat Clay. Organic Clay of Medium to High Plasticity. Peat, Muck and Other Highly Organic Soils. Standard 2-Inch OD Split-Spoon Sample Groundwater After 24 Hours BG Baggie Sample California 2.5-Inch OD Split-Spoon Sample Indicates Date of Reading BK Bulk Sample Rock Core Shelby Tube 3-Inch OD Undisturbed Sample Groundwater at Time of Drilling RG Ring Sample Shorthand Notation: BGS = Below Existing Ground Surface N.E. = None Encountered HSS = Hollow Stem Auger SSS = Solid Stem Auger

15 APPENDIX B Laboratory Test Results

16 CONSOLIDATION TEST RESULTS ASTM D 2435 (Method A) Project: Classroom Addition Albany County Campus Client: LCCC Project Number: WY16316A Lab Number: B-1 at 7' Sample Classification: Reddish Brown SILTY SAND (SM) Sample: In-Situ Tube (Condition: Good) Date Tested: 12/30/16 By: JF Sample Dry Unit Weight: pcf Moisture Content: 10.0% Water ksf -1.4 Vertical Strain, % Load, ksf -4.9

B-1 BORE LOCATION PLAN. EXHIBIT Drawn By: 115G BROOKS VETERINARY CLINIC CITY BASE LANDING AND GOLIAD ROAD SAN ANTONIO, TEXAS.

B-1 BORE LOCATION PLAN. EXHIBIT Drawn By: 115G BROOKS VETERINARY CLINIC CITY BASE LANDING AND GOLIAD ROAD SAN ANTONIO, TEXAS. N B-1 SYMBOLS: Exploratory Boring Location Project Mngr: BORE LOCATION PLAN Project No. GK EXHIBIT Drawn By: 115G1063.02 GK Scale: Checked By: 1045 Central Parkway North, Suite 103 San Antonio, Texas 78232