Zoning Board of Adjustment (BOA)

City of Haslet Agenda Zoning Board of Adjustment (BOA) Meeting Monday, June 15, 2020 at 6:30 PM Meeting by Videoconference and Teleconference Notice is hereby given of a Meeting of the Haslet Zoning Board of Adjustment (BOA) to be held on Monday, June 15, 2020, at 6:30 PM, by video conference and teleconference, which can be joined by any member of the public remotely by calling 1 (866) 899-4679 and entering access code 754-874-277 or by joining online from a computer, tablet or smartphone at https://www.gotomeet.me/HasletCityCouncil/city-of-haslet-city-council-meeting, for the purpose of considering the following agenda items: Page 1. CALL TO ORDER AND ANNOUNCE A QUORUM PRESENT 2. ADMINISTER OATH OF OFFICE TO ALL MEMBERS 3. PUBLIC HEARINGS AND ACTION ITEMS 3.A. To consider a request to vary the interior side yard setback requirement of 3 - 10 Chapter 14, Exhibit A, Section 3.2.4 of the Code of Ordinances of the City of Haslet for construction of a 24 ft. by 30 ft. canopy attached to an existing accessory building. The subject property contains one acre, is in the R-2 Residential Suburban Density 2 zoning district, is described as Lot 13, Block 1, Haslet Park Addition, City of Haslet, Tarrant County, Texas, and is more commonly known as 217 Odessa Drive, Haslet TX. 1) Staff Presentation 2) Public Hearing 3) Discussion 4) Action SR-20-185 - Pdf 3.B. To consider a request to vary the paving requirement of Chapter 14, Exhibit A, 11 - 31 Section 5.5.8.B.2 of the Code of Ordinances of the City of Haslet to allow the use of asphalt, rather than concrete, for a residential driveway. The subject property is approximately five acres, is in the R-1 Residential Suburban Density 1 zoning district, is described as Lot 5, Block 4, Hugh White Estates, City of Haslet, Tarrant County, Texas, and is more commonly known as 2209 White Lane, Haslet TX. 1) Staff Presentation 2) Public Hearing 3) Discussion 4) Action SR-20-190 - Pdf If you have a disability that requires special arrangements and you plan to attend this public meeting, please contact the City Secretary at (817) 439-5931 within 72 hours of the meeting. Reasonable accommodations will be made to meet your needs at the meeting. Zoning Board of Adjustment (BOA) Agenda June 15, 2020 4. EXECUTIVE SESSION The Board of Adjustment may enter into Executive Session during the meeting to seek legal advice from its attorney on any posted agenda item, or to discuss any item that is authorized by the Texas Open Meetings Act to be discussed in closed session, including: 4.A. Section 551.071, Government Code, – Consultation with Attorney; A governmental body may not conduct a private consultation with its attorney except: (1) when the governmental body seeks the advice of its attorney about: (A) pending or contemplated litigation; or (B) a settlement offer; or (2) on a matter in which the duty of the attorney to the governmental body under the Texas Disciplinary Rules of Professional Conduct of the State Bar of Texas clearly conflicts with this Chapter 5. CONSIDER AND ACT ON ANY ITEMS FROM EXECUTIVE SESSION 6. ADJOURN CERTIFICATION I hereby certify that the above notice was posted on the bulletin board at the Haslet Community Center Building at 105 Main Street, Haslet, Texas on Friday, June 12, 2020 before 5:00 p.m. Dianna Buchanan, City Secretary Certification of Notice of Meeting was removed on _________________________,2020 at______________a.m./p.m. by _______________________. Zoning Board of Adjustment (BOA) Agenda June 15, 2020 Page 2 of 31  Agenda Item #3.3.A. Zoning Board of Adjustment (BOA) STAFF REPORT MEETING: Zoning Board of Adjustment (BOA) - 15 Jun 2020 STAFF CONTACT: Walter E. Reeves, Jr. , AICP, Planning Director DEPARTMENT: Planning SUBJECT: To consider a request to vary the interior side yard setback requirement of Chapter 14, Exhibit A, Section 3.2.4 of the Code of Ordinances of the City of Haslet for construction of a 24 ft. by 30 ft. canopy attached to an existing accessory building. The subject property contains one acre, is in the R-2 Residential Suburban Density 2 zoning district, is described as Lot 13, Block 1, Haslet Park Addition, City of Haslet, Tarrant County, Texas, and is more commonly known as 217 Odessa Drive, Haslet TX. 1) Staff Presentation 2) Public Hearing 3) Discussion 4) Action ATTACHMENTS: Attachment 1 Location Map Attachment 2 EXECUTIVE SUMMARY BACKGROUND INFORMATION: The property owner has submitted a request for a variance to the interior side yard setback requirement of the R-2 Residential Suburban Density 2 zoning district in order to construct a 24 ft. X 30 ft. canopy/owning on the front of an existing accessory building on property identified as Lot 13, Block 1, Haslet Park Addition and more commonly known as 217 Odessa Drive (Attachment 1). The existing accessory structure is ten (10) feet from the side property line. The proposed canopy would "square up" with both sides of the existing accessory structure (30 feet) and extend twenty-four (24) feet towards front (Odessa Drive) side of the property (Attachment 2). Pursuant to Chapter 14, Exhibit A, Table 2.4-1, notice was published in the Star-Telegram and notice was placed in the mail to all property owners within 200 feet of the subject property on June 4, 2020. Pursuant to Chapter 14, Exhibit A, Section 2.5.5.G, the Zoning Board of Adjustment (ZBA) shall not approve a variance unless it finds that the criteria in Local Government Code (LGC) Section 211.009(a)(3) are met. Four (4) members of the Board must be present in order to act on any variance request and in order to grant a variance 75% of the voting Board members (4 members) must vote in favor of the proposed variance. if four (4) votes in favor of the requested variance are not achieved, the variance request is deemed "denied. The criteria of LGC Section 211.009(a)(3) are: The variance is not contrary to the public interest. The public interest involved with this request is the required fifteen (15) foot interior side setback. That setback is intended to assure a minimum amount of Page 3 of 31  Agenda Item #3.3.A. undeveloped open space on each property subject to the R-2 district regulations. This is probably the most important criteria to address in this request, as answers to the other three criteria flow from a determination on this criteria. The existing accessory building is approximately 900 square feet (30 ft. X 30 ft.) and approximately 150 square feet of that building is within the required side yard setback. While the application materials indicate that the request is for a 2.5 ft. variance from the corner post of the canopy, the actual variance required is measured from edge of the canopy, not the post, as the canopy meets the definition of a "structure" in the Zoning Ordinance definitions. The actual variance required is five feet and the encroachment of the canopy would result in a 120 square foot loss of 'open space." Given that all of the area to be covered by the canopy is either paved or graveled and that the abutting neighbor is in favor of the variance (Attachment 2) it is hard to see what public interest, other than the loss of 120 square feet of paved and graveled "öpen space" is served in finding that the variance is contrary to the public interest. Due to special conditions, a literal enforcement of the ordinance would result in unnecessary hardship. The location of the existing accessory structure could be considered a "special condition". While an awning/canopy can be constructed that would meet the required fifteen (15) foot setback, such a canopy would not "square up" with the western side of the structure and would leave one of the two garage doors partially uncovered. If the Board believes that granting the variance is not contrary to the public interest, and believe that the existing accessory structure is a "special condition," it would follow that literal enforcement would result in unnecessary hardship. The spirit of the ordinance is observed. There would still be a ten foot strip of "open space" between the existing accessory structure and the canopy. If the Board determines that the variance is not contrary to the public interest, and that there is a special condition such that literal enforcement of the ordinance would result in unnecessary hardship, the Board could determine that the spirit of the ordinance is observed by the remainder of the interior side yard setback. Substantial justice is done. If the Board has determined that the previous three criteria are met, it would logically follow that substantial justice has been done. Finally, pursuant to Chapter 14, Exhibit A, Section 2.5.5 H, any party aggrieved by the Board's decision has ten (10) days to appeal to a court of record in the appropriate county. In this case, that would be Tarrant County. RECOMMENDATION(S): Staff recommends approval of the requested variance to allow a 24' X 30' canopy to be attached to an existing accessory structure to encroach no more than 5 feet into the required interior side yard setback. SUGGESTED MOTION: I move we approve the requested variance to allow a 24' X 30' canopy to be attached to an existing accessory structure to encroach no more than 5 feet into the required interior side yard setback. James Quin, City Administrator Approved - 09 Jun 2020 Rob Allibon, City Attorney Approved - 08 Jun 2020 Page 4 of 31  Agenda ItemCity of Haslet #3.3.A. 101 Main St. Haslet ,TX 76052 www.haslet.org (817) 439-5931 Attachment 1 / 0 0.065 0.13 Sources: Esri, HERE, Garmin, Intermap, increment P Corp., GEBCO, USGS, FAO, NPS, NRCAN, GeoBase, IGN, Kadaster NL, Ordnance Survey, Esri Japan, mi METI, Esri China (Hong Kong), (c) OpenStreetMap contributors, and the GIS User Community, Halff Legend polygonLayer Incorporated Override 1 ETJ Override 2 Page 5 of 31 Parcels ATTACHMENT 2 Agenda Item #3.3.A. Page 6 of 31 Agenda Item #3.3.A. Page 7 of 31 Agenda Item #3.3.A. Page 8 of 31 Agenda Item #3.3.A. Page 9 of 31 Agenda Item #3.3.A. Page 10 of 31  Agenda Item #3.3.B. Zoning Board of Adjustment (BOA) STAFF REPORT MEETING: Zoning Board of Adjustment (BOA) - 15 Jun 2020 STAFF CONTACT: Walter E. Reeves, Jr. , AICP, Planning Director DEPARTMENT: Planning SUBJECT: To consider a request to vary the paving requirement of Chapter 14, Exhibit A, Section 5.5.8.B.2 of the Code of Ordinances of the City of Haslet to allow the use of asphalt, rather than concrete, for a residential driveway. The subject property is approximately five acres, is in the R-1 Residential Suburban Density 1 zoning district, is described as Lot 5, Block 4, Hugh White Estates, City of Haslet, Tarrant County, Texas, and is more commonly known as 2209 White Lane, Haslet TX. 1) Staff Presentation 2) Public Hearing 3) Discussion 4) Action ATTACHMENTS: Attachment 1 Attachment 2 Attachment 3 EXECUTIVE SUMMARY BACKGROUND INFORMATION: The property owner has submitted a request for a variance to allow the use of asphalt in replacing a failing concrete driveway on property identified as Lot 5, Block 4, Hugh White Estates and more commonly known as 2209 White Lane (Attachment 1). The existing concrete driveway is failing and the applicant proposes to replace it with three (3) inches of Type "D" hot mix asphalt. The driveway is approximately 14 feet wide and 725 feet in length (Attachment 2). Also accompanying this application is a geotechnical report that does not support the use of asphalt as appropriate in this situation, but instead makes recommendations on the type of foundation to used on the property (Attachment 3). Pursuant to Chapter 14, Exhibit A, Table 2.4-1, notice was published in the Star-Telegram and notice was placed in the mail to all property owners within 200 feet of the subject property on June 4, 2020. Pursuant to Chapter 14, Exhibit A, Section 2.5.5.G, the Zoning Board of Adjustment (ZBA) shall not approve a variance unless it finds that the criteria in Local Government Code (LGC) Section 211.009(a)(3) are met. Four (4) members of the Board must be present in order to act on any variance request and in order to grant a variance 75% of the voting Board members (4 members) must vote in favor of the proposed variance. if four (4) votes in favor of the requested variance are not achieved, the variance request is deemed "denied. The criteria of LGC Section 211.009(a)(3) are: Page 11 of 31  Agenda Item #3.3.B. The variance is not contrary to the public interest. Chapter 14, Exhibit A, Section 5.5.8.B.2 of the Code of Ordinances of the City of Haslet states;"All parking areas, drive aisles, and fire lanes shall be of concrete paving unless alternative paving materials are approved as part of a siteplan." The existing concrete driveway is failing and the applicant is requesting to use asphalt as the replacement paving material rather than concrete. Concrete is a longer lasting and more durable material than asphalt. This standard has been adopted as part of both the City's zoning and subdivision regulations. Since the adoption of this standard, all other "parking areas, drive aisles, and fire lanes" within the City have been constructed with concrete, with the exception of the BNSF Auto Storage Lot, which was approved with asphalt for the parking area through the site plan approval process. Asphalt would be a lesser standard and it is hard to see how the public interest would be served by varying this requirement. Due to special conditions, a literal enforcement of the ordinance would result in unnecessary hardship. There are no special conditions associated with this request. The applicant has provided a geotechnical report and Mr. Travis Attanasio, City Engineer, provides the following comments; "The only sentence concerning paving is such “Areas that will underlay fill or pavement should be proof-rolled prior to fill operations.” As this does not address pavement thickness or type I would not accept this report as supporting evidence." Absent any special condition, it is hard to imagine how literal enforcement would result in unnecessary hardship. The spirit of the ordinance is observed. To allow the use of asphalt in the absence of any special condition would be contrary to the spirit of the ordinance and would be granting a special privilege to a single property owner. Substantial justice is done. As none of the preceding three criteria are met, granting of the requested variance would result in substantial justice being done. Finally, pursuant to Chapter 14, Exhibit A, Section 2.5.5 H, any party aggrieved by the Board's decision has ten (10) days to appeal to a court of record in the appropriate county. In this case, that would be Tarrant County. RECOMMENDATION(S): Staff recommends denial of the request to vary the requirement of Chapter 14, Exhibit A, Section 5.5.8.B.2 of the Code of Ordinances of the City of Haslet to allow asphalt as the paving requirement rather than concrete for Lot 5, Block 4, Hugh White Estates. SUGGESTED MOTION: I move we deny the requested variance to vary the requirement of Chapter 14, Exhibit A, Section 5.5.8.B.2 of the Code of Ordinances of the City of Haslet to allow asphalt as the paving requirement rather than concrete for Lot 5, Block 4, Hugh White Estates. James Quin, City Administrator Approved - 08 Jun 2020 Rob Allibon, City Attorney Approved - 08 Jun 2020 Page 12 of 31  Agenda ItemCity of Haslet #3.3.B. 101 Main St. Haslet ,TX 76052 www.haslet.org Location Map (817) 439-5931 / 0 0.065 0.13 Sources: Esri, HERE, Garmin, Intermap, increment P Corp., GEBCO, USGS, FAO, NPS, NRCAN, GeoBase, IGN, Kadaster NL, Ordnance Survey, Esri Japan, METI, Esri China (Hong Kong), (c) OpenStreetMap contributors, and the GIS mi User Community, Halff Legend polygonLayer Incorporated Override 1 ETJ Override 2 Page 13 of 31 Parcels ATTACHMENT 2 Agenda Item #3.3.B. Page 14 of 31 Agenda Item #3.3.B. Page 15 of 31  ATTACHMENT 3 Agenda Item #3.3.B. geotechnical and construction materials consultants November 15, 2016 Report No. 17039G Melchiros Architecture 600 E Rosedale Street, Suite 104 Fort Worth, Texas 76104 ATTN: Mr. Matthijs Melchiros Phone: 817-653-3007 Email: matthijs@melarch.com RE: Geotechnical Investigation White Lane Residence 2209 White Lane Haslet, Texas Gentlemen: Presented herein is the report of a geotechnical investigation conducted by Henley-Johnston & Associates, Inc. for the above referenced project. We appreciate the opportunity to provide this report to you. If we can be of further service or if you desire any additional information, please do not hesitate to call. Signed, HENLEY-JOHNSTON & Associates, Inc. The seal appearing on this Jordan Scoville, E.I.T. James F. Phipps, P.E. document was authorized by Project Manager Vice President James F. Phipps, P.E. 84778 on November 15, 2016. Firm Registration No.: F-1238 Copies submitted (1) Melchiros Architecture – Mr. Matthijs Melchiros (1) Mr. Jim Shivers (1) Stovall Structural Engineers – Mr. Elliott Stovall Page 16 of 31  Agenda Item #3.3.B. INDEX INVESTIGATION AND ANALYSIS 1 Introduction 1 Field and Laboratory Investigation 1 Surface and Subsurface Conditions 1 Potential Vertical Movement Analysis 2 DESIGN AND CONSTRUCTION RECOMMENDATIONS 3 Introduction 3 Foundation Recommendations 3 Construction Considerations 6 Earthwork Recommendations 7 Construction Testing and Observation 8 Plates Page 17 of 31  Agenda Item #3.3.B. Report No. 17039G November 15, 2016 INVESTIGATION AND ANALYSIS Introduction This report presents the results of a subsurface investigation performed for a proposed single- family residence to be located at 2209 White Lane in Haslet, Texas. The purpose of this investigation was to evaluate subsurface conditions and provide recommendations for design and construction of the foundation. It was anticipated that a ground-supported slab would be used to provide foundation support of the residence. This investigation was conducted in accordance with the “Recommended Practice for the Design of Residential Foundations” produced by the Texas Section American Society of Civil Engineers. This report is specific to this site. Persons using the recommendations herein for projects and/or designs not covered by this report do so at their own risk. Field and Laboratory Investigation Subsurface conditions were evaluated using two soil borings. Locations of the borings were dictated by site accessibility and are presented on Plate 1. Borings were drilled using a truck- mounted rig equipped with continuous flight augers and extended to a depth of 25 feet below existing (October 2016) grades. Drilling and sampling were done in general accordance with ASTM methods and standards. Relatively undisturbed samples of cohesive soil and weathered shale were obtained with three-inch diameter thin-walled Shelby tubes. Weathered limestone was evaluated using the TxDOT Cone Penetration Test (TCP). All samples were transported to our laboratory for visual classification and testing. Soils were visually classified according to the Unified Soil Classification System (USCS). Rock materials were described using standard geological nomenclature. The Boring Logs and a key to terms and symbols used on the logs are attached. Selected samples were tested to evaluate engineering properties, soil movement, and confirm visual classification. Tests conducted included Atterberg Limits (ASTM D-4318) and moisture content determinations (ASTM D-2216). A free-swell test and an absorption pressure-swell test were conducted to evaluate the potential for soil related heave. The strength of a selected sample was investigated by the Unconfined Compression test. Results of the laboratory tests are presented on Plates 2 and 3. Surface and Subsurface Conditions At the time of the field investigation the property was occupied by an existing structure. Within the depths drilled, subsurface conditions consisted of clay soils over severely weathered to Page 18 of 31 -1-  Agenda Item #3.3.B. Report No. 17039G November 15, 2016 weathered limestone, and severely weathered to slightly weathered shale within the Lower Cretaceous Pawpaw Formation, Weno Limestone, and Denton Clay undivided. At the surface, residual clay soils were encountered. These clays were brown in appearance, moderately plastic, contained varying amounts of limestone fragments, and continued to depths of ½-foot to 2 feet below existing grades. Severely weathered to weathered limestone was encountered directly underlying the clay soils. This weathered limestone was soft to hard (rock hardness classification), tan in appearance, and continued to a depth of 6 feet below existing grades. Weathered to slightly weathered shale was present below the weathered limestone. This weathered shale was laminated, soft, reddish-brown and gray in appearance, and extended through the termination depths of the borings. It possessed the engineering quality of CH clay, as noted in the laboratory summary, and contained some iron staining. Based on soil moisture and pocket penetrometer values, the residual soil profile was generally dry at the time of the field investigation. Ground water was not noted during the field investigation within the depths drilled. The presence and depth to ground water will vary depending upon seasonal rainfall amounts. When present, ground water will perch within the open cracks and fissures of the weathered rock. Potential Vertical Movement Analysis Subsurface conditions at the site are comprised of clay soils and weathered shale. Potential Vertical Movements (PVM) related to soil at this site will be a combination of seasonal movements within the upper clays, and heave within the weathered shale. For clay soils, movements are associated with changes in seasonal moisture conditions. After periods of rain, the clays expand resulting in heave of overlying elements. During dry seasons, these soils shrink resulting in settlement of ground-supported features. In weathered shale, movements are associated with an increase in subsurface moisture after construction of the foundation. These movements are manifested as a gradual and sustained heave of the foundation. Potential Vertical Movements (PVM) were evaluated using TxDOT Method 124E 1 and results of the free-swell tests. Based on this analysis, total soil movements from a dry to saturated state are anticipated to be on the order of 2 to 3 inches. This is considering that less than 2 feet of fill 1 “Method for Determining the Potential Vertical Rise, PVR.” Texas Department of Transportation Method Tex-124-E, 1978. Page 19 of 31 -2-  Agenda Item #3.3.B. Report No. 17039G November 15, 2016 is placed below the foundation under controlled conditions as outlined in the Earthwork Recommendations section. If the foundation were to be constructed over a dry subgrade and/or the subgrade soils were given unlimited access to moisture, such as from leaking irrigation or utility lines, greater amounts of movement should be anticipated. DESIGN AND CONSTRUCTION RECOMMENDATIONS Introduction It is anticipated that a ground-supported foundation will be used for structural support. Considering potential vertical movements of 2 to 3 inches, remedial earthwork is not considered necessary for this site. Recommendations for design and construction of the foundation are presented in the following sections. Foundation Recommendations Current literature indicates 4 to 4-1/2 inches is the maximum amount of movement a ground supported, stiffened slab can withstand. Considering potential vertical movements of 2 to 3 inches, a ground supported, stiffened slab may be used if some post-construction movement is acceptable. If no movement can be tolerated, a suspended floor coupled with a pier and beam foundation should be used. Recommendations for this type of foundation can be provided upon request. Ground-Supported Foundation Recommendations A ground-supported foundation may be either conventionally reinforced or post-tensioned. A conventionally reinforced foundation may be designed using the Wire Reinforcement Institute (WRI) and/or the Building Research and Advisory Board (BRAB) 2 method. For this site, an Average Weighted Plasticity Index (PIw) of 28 was recommended. Considering slopes of less than 5% for a graded site, and using an unconfined compressive strength (Qu) of 4.0 kips per square foot (ksf), a Slope Correction Factor (CS) of 1.0 and an Over-Consolidation Correction Factor (CO) of 0.85 should be used with the WRI Method. This results in an Effective PI of 24. A Climatic Rating (CW ) of 20 is considered appropriate for this site. Based on the above values, a Support Index (C) of 0.87 is applicable for the BRAB Method, and a value of 0.09 (1-C) should be used for a WRI design. With the WRI method, a cantilevered 2 Building Research Advisory Board, “Report 33 to the Federal Housing Administration Criteria for Selection and Design of Residential Slab-on-Ground,” Publication 1571 National Academy of Sciences, Washington, D.C., 1968. Page 20 of 31 -3-  Agenda Item #3.3.B. Report No. 17039G November 15, 2016 length (lc) of 3.6 feet was derived using the previous information. It is recommended the lc be increased by a factor of 1.5 with a minimum length of 6 feet for analysis purposes 3. Design of post-tensioned slabs is based on the Edge Moisture Variation Distance (em), and the anticipated Differential Movements (ym) that can occur over this distance em. The em is based on the amount of anticipated annual rainfall and is derived from the Thornthwaite Index (TI). This index is measured in inches and indicates the amount of rainfall above or below the amount needed to support plant growth. It has been found that irrigation and landscaping can increase the TI by several inches. For this project a modified TI range of -10 to +10 was used. Differential movements (ym) for design of slabs can be determined according to the Post- Tensioning Institute (PTI) 4. Differential movements for center lift and edge lift conditions are based on type of clay minerals, velocity of moisture flow through the subgrade, and depth to constant soil suction. If the adverse effects of vegetation, site drainage, and slope have been corrected, differential movements may be calculated using the method presented in the PTI manual. Based on experience in the North Texas area, differential movements for slabs on-ground can approach the total potential movement estimated from laboratory test results. The em and ym values presented in Table 1 were derived using the PTI method. These values were modified considering the effect of irrigation on the TI and the results of the PVM analysis. Values in Table 1 may be used for dry subsurface conditions. Table 1 PTI DESIGN VALUES for DRY SOIL CONDITIONS (PVM = 2 to 3 inches) 2209 White Lane Haslet, Texas Edge Moisture Variation Distance Differential Movement Lift Condition em (ft.) ym (in.) Center Lift 5.0 1.2 Edge Lift 4.3 1.9 3 Recommended Practice for the Design of Residential Foundations, Version 1, Texas Section of the American Society of Civil Engineers (2002), p 10. 4Design and Construction of Post-Tensioned Slabs-on-Ground, 3rd Edition, Post-Tensioning Institute, Phoenix, AZ (2008). Page 21 of 31 -4-  Agenda Item #3.3.B. Report No. 17039G November 15, 2016 Grade beams should penetrate a minimum of 12 inches below finished grade and rest on undisturbed soil or compacted and tested fill. Beams may be sized using an allowable net bearing pressure of 3.0 ksf. This allowable bearing value contains a Factor of Safety of 3 considering a shear failure. The foundation should be designed to conform to the stiffness criteria presented in Table 6.2 of the current PTI Manual for different types of construction. Pier Recommendations If piers will be used for foundation support it is recommended that they be designed as straight- shaft piers and penetrate a minimum of one-foot into the tan, weathered limestone which was encountered at a depth of ½ to 2 feet from existing grades. All piers should have a minimum overall length of 6 feet. Piers should be designed for an allowable end bearing of 20.0 kips per square foot (ksf) considering a Factor of Safety of 3 against a shear or plunging failure. For straight-shaft piers, a skin friction value of 2.5 ksf may be applied to that portion of the pier shaft below the minimum penetration of one foot into the limestone. The weight of the concrete may be neglected when determining foundation loads. Settlements of approximately ½-inch should be anticipated for this allowable bearing capacity. Temperature reinforcing will be adequate to resist uplift forces associated with heaving of the subsurface soils. A minimum one No. 5 vertical bar is recommended. Resistance to uplift will be a function of the dead weight of the concrete in the pier and axial load. A negative skin friction of 1.2 ksf may be used for that portion of a straight shaft pier below the minimum one-foot penetration. Pier shaft excavations should be clean of all debris and dry prior to placement of concrete. Ground water was not encountered during drilling operations within the depths drilled. Ground water may develop after periods of prolonged rainfall and/or irrigation. It is recommended an allowance be made for the use of temporary casing in the event water is encountered during pier construction. Concrete should be placed within eight hours after each shaft is drilled. Excess concrete at the top of the pier shaft should be removed prior to placement of the exterior grade beam. Construction Considerations Expansion joints should be installed at locations selected by the architect to allow for deflection of interior walls. All loose soils, debris, and water should be removed from grade beam and pier excavations prior to placing concrete. The width and depth of grade beams should not vary across the length of the beam. Page 22 of 31 -5-  Agenda Item #3.3.B. Report No. 17039G November 15, 2016 A vapor barrier should be installed below the slab. All penetrations and joints should be sealed to lower the potential for migration of moisture through the floor. Plastic sheeting used for vapor retarders below the slabs should be draped or cut in such a way as to allow concrete to be placed directly against the sidewalls of the grade beam excavations. Sand and gravel should not be used to bed utility lines. Utility excavations should be backfilled using on-site soils placed under controlled conditions as outlined in the Earthwork Recommendations section. As a minimum, a four-foot long clay plug should be installed below the exterior grade beam where utility lines transition below the foundation. This clay plug should be installed as outlined in the Earthwork Recommendations section. If possible, all utility trenches should be sloped to drain away from the foundation. Positive drainage away from the foundation should be established during construction and maintained throughout the life of the structure. Landscaping beds should be designed and maintained to prevent water from ponding next to the foundation. Ponded water will increase subsurface moisture and consequently increase the potential for heave. Irrigation lines or heads should not be placed directly next to the foundation. It is recommended that all irrigation lines be kept a minimum of five feet from the edge of the residence. If possible, trees should not be planted directly next to the house. Over time, vegetation will desiccate the clays, resulting in shrinkage of the subgrade. This shrinkage will be manifested as settlement of ground supported foundations. All trees should be planted a minimum of 1-1/2 times the mature height of the tree from the foundation. If trees will be planted next to the structure, consideration should be given to installing a vertical root barrier between the tree and the foundation. As a minimum the barrier should consist of a four-inch wide lean concrete wall extending to a depth of 6 feet from finished grade. An alternative is to use a minimum 6-mil thick plastic sheet draped within the excavation and backfilled using sand or gravel. Alternately, a “root-barrier” system similar to that produced by DeepRoot® may be installed around the perimeter of the foundation. Vegetation should be planted outside of the root barrier, away from the foundation. Any trees to be cleared from or within ten feet of the building pad should have the root systems removed and the excavations filled with on-site soils placed under controlled conditions. Soils should be placed as presented in the Earthwork Recommendations section. Earthwork Recommendations Prior to construction, the site should be stripped of all organic soils. Areas that will underlay fill or pavement should be proof-rolled prior to fill operations. Any soft areas should be excavated to firm soils (pocket penetrometer reading of 2.0 tons per square foot or greater), and then filled using on-site materials. On-site soils should be placed in maximum eight-inch loose lifts and Page 23 of 31 -6-  Agenda Item #3.3.B. Report No. 17039G November 15, 2016 compacted to a minimum of 95% of the maximum density as determined by ASTM D-698. Moisture content should be a minimum of +2% above optimum. If additional fill will be required to bring the pad to finished subgrade, on-site soils or equivalent should be used. These soils should be placed and compacted to the moisture and density as outlined above. Excavated limestone used as fill should be reduced to a maximum nominal diameter of 3 inches and placed in maximum 8-inch loose lifts. Limestone fragments should be compacted to a minimum of 95% (ASTM D-698) with moisture contents between –2 and +3 percentage points of optimum. If required, imported select fill should have a Liquid Limit of 30 or less and a Plasticity Index of 5 to 15. Select fill should be placed in maximum 8-inch loose lifts and compacted to a dry density between 95 and 98 percent of the maximum dry density obtained by the Standard Proctor Compaction Test (ASTM D 698). The moisture content of the compacted soils should be maintained between –2 and +2 percent of the optimum value (determined from ASTM D 698). Fill around perimeter grade beams should be on site clay, cleaned of all construction debris and placed in a controlled manner as discussed in the previous paragraph. Use of clean, compacted fill will lower the potential for water to migrate below the slab and into the subgrade soils. Construction Testing and Observation It is recommended that a representative of Henley-Johnston & Associates, Inc. be retained to visually inspect the foundation excavation prior to placement of concrete to confirm proper bearing stratum and adherence with the recommendations of this report. Field density tests should be taken at a rate of two tests per lift of fill to confirm that compaction and soil moisture meet the requirements presented herein. Field density testing must be conducted during placement of fill. Samples of the fill material should be submitted to the testing laboratory a minimum of 72 hours prior to commencing earthwork operations to allow for evaluation of the maximum density and optimum moisture of the fill soils. Page 24 of 31 -7-  Agenda Item #3.3.B. LEGEND SOIL BORING 1 2 WHITE LANE RESIDENCE HJA No.: 17039G 2209 WHITE LANE HASLET, TEXAS DATE: OCTOBER 2016 235 MORGAN AVE. DALLAS, TX 75203 I 214.941.3808 I WWW.HJA-ENG.COM TEXAS FIRM REGISTRATION NO. F-1238 BORING LOCATION PLAN PLATE 1 Page 25 of 31  GEOTECHNICAL INVESTIGATION Agenda Item #3.3.B. REPORT NO. 17039G WHITE LANE RESIDENCE 2209 WHITE LANE HASLET, TEXAS SUMMARY OF INDEX PROPERTIES BORING DEPTH LIQUID PLASTIC DUW FINER MOISTURE UNIFIED SOIL NUMBER (ft.) LIMIT INDEX (pcf) #200 CONTENT CLASSIFICATION (%) (%) (%) 1 0.0 – 1.0 13.2 1 1.0 – 2.0 31 14 98.6 12.5 CL 1 2.0 – 3.0 8.1 1 7.0 – 8.0 12.5 1 8.0 – 9.0 12.2 1 9.0 – 10.0 22.4 1 14.0 – 15.0 23.8 1 19.0 – 20.0 20.1 1 24.0 – 25.0 19.2 2 0.0 – 1.0 5.5 2 7.0 – 8.0 19.4 2 8.0 – 9.0 20.8 2 9.0 – 10.0 68 44 99.4 25.7 CH 2 14.0 – 15.0 109.7 18.1 2 19.0 – 20.0 24.8 2 24.0 – 25.0 20.3 SUMMARY OF FREE-SWELL TESTS BORING DEPTH SWELL GAIN IN PERCENT MATERIAL DESCRIPTION NUMBER (ft.) PRESSURE MOISTURE SWELL (psf) (%) (%) 1 1.0 – 2.0 144.0 10.3 0.0 CLAY, very stiff, brown SUMMARY OF ABSORPTION PRESSURE-SWELL TESTS BORING DEPTH SWELL GAIN IN PERCENT MATERIAL DESCRIPTION NUMBER (ft.) PRESSURE MOISTURE SWELL (psf) (%) (%) 2 9.0 – 10.0 3,363.0 7.3 7.2 SHALE, weathered Page 26 of 31 Plate 2  GEOTECHNICAL INVESTIGATION Agenda Item #3.3.B. REPORT NO. 17039G WHITE LANE RESIDENCE 2209 WHITE LANE HASLET, TEXAS SUMMARY OF UNCONFINED COMPRESSION TESTS - SOIL BORING DEPTH PEAK FAILURE MATERIAL DESCRIPTION NUMBER (ft.) STRESS STRAIN (psi) (%) 2 14.0 – 15.0 40.1 3.4 SHALE, weathered Page 27 of 31 Plate 3  Agenda Item #3.3.B. LEGEND, LITHOLOGY, SOIL CONSISTENCY TEXAS FIRM REGISTRATION NO. F-1238 235 MORGAN AVE. DALLAS. TEXAS 75203 I 214.941.3808 I WWW.HJA-ENG.COM & RELATIVE ROCK HARDNESS CLASSIFICATION CONSISTENCIES AND HARDNESS SYMBOLS DESCRIPTIONS SOIL FOR SANDS, GRAVELS & SANDY SILTS Modified from Peck, Hanson & Thornburn (1974) Asphalt or Lignite Consistency Standard Penetration Resistance N Concrete Very Loose Less than 4 Loose 4 to 10 Fill Medium Dense 10 to 30 Gravel or Sandy Gravel; well GW graded Dense 30 to 50 Gravel or Sandy Gravel; poorly Very Dense Greater than 50 GP graded GM Silty Gravel or Silty Sandy Gravel FOR CLAYS AND SANDY CLAYS (COHESIVE SOILS) Clayey Gravel or Clayey Sandy GC Gravel Modified from Peck, Hanson & Thornburn (1974) Standard Unconfined SW Sand or Gravelly Sand, well graded Consistency Compression tsf Penetration Sand or Gravelly Sand; poorly Resistance N SP graded Very Soft Less than 0.25 Less than 2 SM Silty Sand or Silty Gravelly Sand Soft 0.25 to 0.5 2 to 4 Clayey Sand or Clayey Gravelly Medium Stiff 0.5 to 1.0 4 to 8 SC Sand Silts, Sandy Silts, Gravelly Silts, or Stiff 1.0 to 2.0 8 to 15 ML Diatomaceous Soils Low Plasticity Clays, Gravelly Clays Very Stiff 2.0 to 4.0 15 to 30 CL or Sandy Clays Hard Greater than 4.0 Greater than 30 Organic Silts or Low Plasticity OL Organic Clays Micaceous Clays or Diatomaceous RELATIVE HARDNESS MODIFIERS (ROCK) MH Soil (RELATED TO FRESH SAMPLE) Modified from SCS EWP, Tech Guide No. 4 CH High Plasticity Clays Hardness Rule of Thumb Test OH High Plasticity Organic Clays Soft Permits denting by moderate finger pressure Rock Resists denting by fingers but can be penetrated by Firm pencil point to medium to shallow depth Ls Limestone (No. 2 pencil) Sh Shale Very shallow penetration of pencil point, can be Mod. Hard scratched by knife and in some instances cut with knife Mr Marl Ss Sandstone Hard No pencil penetration, can be scratched with knife, can be broken by light to moderate hammer blows Fracture Zone Cannot be scratched by knife, can be broken by Very Hard repeated heavy hammer blows Weathered Zone Page 28 of 31  Agenda Item #3.3.B. LOG OF BORING PROJECT No.: 17039G BORING No.: 1 White Lane Residence STATION: DRILL DATE: 10/31/16 2209 White Lane SHEET: 1 of 1 METHOD: Shelby Tube to 25' Haslet, Texas LOCATION: See Plate 1 GROUND ELEVATION: CORE TxDOT1CPT 2 (inches 3 per 100 blows) 4 5 6 RECOVERED (ft.) MATERIAL DESCRIPTION ELEVATION STANDARD PENETRATION (BPF) SAMPLES DRILLED (ft.) 10 20 30 40 50 60 SYMBOL DEPTH (feet) POCKET PENETROMETER (tsf) (feet) 1 2 3 4 + ++ 0 CLAY, with limestone fragments, very stiff, brown LIMESTONE, severely weathered, soft, tan LIMESTONE, weathered, hard, tan 4 1.75" SHALE, weathered, laminated, slightly calcareous, with iron staining, soft, reddish-brown 8 12 16 20 SHALE, slightly weathered, thinly laminated, calcareous, with iron staining, soft, gray 24 TOTAL DEPTH: 25.0' 28 Ground Water During Drilling (ft.): DRY Ground Water at Completion (ft.): DRY Page 29 of 31  Agenda Item #3.3.B. LOG OF BORING PROJECT No.: 17039G BORING No.: 2 White Lane Residence STATION: DRILL DATE: 10/31/16 2209 White Lane SHEET: 1 of 1 METHOD: Shelby Tube to 25' Haslet, Texas LOCATION: See Plate 1 GROUND ELEVATION: CORE TxDOT1CPT 2 (inches 3 per 100 blows) 4 5 6 RECOVERED (ft.) MATERIAL DESCRIPTION ELEVATION STANDARD PENETRATION (BPF) SAMPLES DRILLED (ft.) 10 20 30 40 50 60 SYMBOL DEPTH (feet) POCKET PENETROMETER (tsf) (feet) 1 2 3 4 + ++ 0 CLAY, with limestone fragments, very stiff, brown LIMESTONE, severely weathered, soft, tan LIMESTONE, weathered, hard, tan 4 1.75 SHALE, weathered, laminated, slightly calcareous, with iron staining, soft, reddish-brown 8 12 16 20 SHALE, slightly weathered, thinly laminated, calcareous, with iron staining, soft, gray 24 TOTAL DEPTH: 25.0' 28 Ground Water During Drilling (ft.): DRY Ground Water at Completion (ft.): DRY Page 30 of 31 Agenda Item #3.3.B. Page 31 of 31