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HomeMy WebLinkAboutContract 45454-A1 (2)STATE OF TEXAS COUNTY OF TARRANT AMENDMENT NO. 1 to AGREEMENT for CONSTRUCTION ADMINISTRATION SERVICES for the POLICE AIR SUPPORT HANGAR at MEACHAM INTERNATIONAL AIRPORT Ill I CITY SECRETARY CONTRACT NO I5L154/1 ` ' WHEREAS, The City of Fort Worth and Charles Willis and Associates, Inc. (Architect) made and entered into City Secretary Contract No. 45454 (The Contract) which was duly authorized by Assistant City Manager, Fernando Costa, the 27th day of March, 2014; and WHEREAS, further amendment is necessary for additional design services to provide structural engineer design services for the revision of the structural concrete slab design; and NOW THEREFORE, City and Architect, acting herein by and through their duly authorized representatives, enter into the following agreement which amends the Contract: 1 Article 1.1, SECTION I — SERVICES OF THE ARCHITECT, a paragraph is added to read as follows: "Provide design services to revise the structural concrete slab design due to unanticipated variations in the subsurface conditions discovered on site. The cost of this Additional Service is $1,980.00. The Additional Services is described more fully in the Charles Willis and Associates, Inc's letter dated June 5, 2014 subject: Proposal for Additional Engineering Services, Redesign of Foundations as Straight Shaft Piers, Fort Worth Police Department Meacham Field Helicopter Facility, Charles Willis & Associates, Inc. Project No. FTW-01, which is attached hereto as Attachment "A" and made a part of this Agreement." 2 Paragraph 1 of SECTION V - COMPENSATION TO ARCHITECT, is amended as follows: "The total compensation for all of the assignments to be performed by Architect as described in CHARACTER AND EXTENT of ARCHITECT'S SERVICES hereof shall be a fixed fee of $42,700.00 plus up to $1,500.00 in reimbursable expenses." 3 All other provisions of this Contract which are not expressly amended herein shall remain in full force and effect. XXXXXXXXXXXXXXXX The Remainder of This Page Is Intentionally Left Blank XXXXXXXXXXXXXXXX RECEIVED JU a r � t ! nil ppg L gf NCB ©Dr!OFI©Ts( il_Wt i!' J o /1Jl''1F t-f fvtirj it i Police Air Support Hangar, Meacham International Airport Page 1 of 2 EXECUTED this the 1'K—day of 7k42-----2014, in Fort Worth, Tarrant County, Texas. By: Charles Willis and Associates, Inc. ti Ch.-aisles A. Willis, AIA, NCARB President APPROVAL RECOMMENDED: By: gre CL:/ C� Douglas Wiersig, PE Director, Transportation & Public Works Dept. APPROV Ek AS 0 FORM AND LEGALITY: By: Douglas W. Black Assistant City Attorney APPROVED: By: �Gl�i4+4O (.II.1.---. Fernando Costa Assistant City Manager RECORDED§ By: ary J. City Secretary M&C Contract Authoriz Date: t vicr OFFICIAL RECORD ©tB'V SECRETARY WORTN9 TX Police Air Support Hangar, Meacham International Airport Page 2 of 2 ALL STRUCTURAL ENGINEERING • June 2, 2014 Mr. Charles Willis Principal Willis Inc. 1161 Corporate Drive, Suite 150 Arlington Texas 76006 Re: Proposal for Additional Engineering Services Redesign of Foundations as Straight Shaft Piers Fort Worth Police Department Meacham Field Helicopter Facility Callahan Engineering Project No. 1216.00 Dear Chuck: x'C l +-kMv-i.rr n,tl We appreciate the opportunity to offer our professional services for the referenced project. Below I have outlined my understanding of your needs, our scope of work, and fee. Scope of Additional Services: Provide design and construction drawings for a revised foundation using straight shaft piers as outlined in the attached Geotechnical Engineering Report provided by Terracon Consultants, Inc. dated 5/30/14. Providing engineering services to design the above listed item(s) is outside the original scope of structural work for the project; therefore we respectfully request additional compensation for this engineering work. Additional Fee Proposal: Callahan Engineering's fee for the additional services described herein will be the lump sum of Eighteen Hundred ($1,800.00) dollars Professional Services Agreement: The rights, duties, and obligations of the Client, GRW Wdlis, Inc., and the Engineer, Callahan Engineering Inc., will be performed in accordance with the terms and conditions of the Agreement for Professional Services between Client and Engineer dated May 22, 2001, which is fully incorporated herein by reference. CALLAHAN ENGINEERING INC 817 W. TUCKER ST. FORT WORTH TX 76104 817.335.3909 (v) 817.335.3908 (0 Mr. Charles Willis June 2, 2014 Page 2 of 2 Thank you for the opportunity to submit this proposal. We look forward to working with your firm on this project. Sincerely, Accepted: 4 Title: Patrick K. Callahan, PE President Date: CALLAHAN ENGINEERING INC 817 W. TUCKER ST. FORT WORTH TX 76104 817.335.3909 (v) 817.335.3908 (f) May 30, 2014 City of Fort Worth Architectural Services 410 W. 13th Street Fort Worth, Texas 76102-4616 Attn: Mr. Alfonso Meza E: alfonso.meza@fortworthtexas.gov Re: Geotechnical Engineering Report FWPD Aviation Administration Building 310 Gulfstream Road Fort Worth, Texas Terracon Project Number: 95145056 Dear Mr. Meza: lierrecon Terracon Consultants, Inc. (Terracon) has completed the geotechnical engineering services for the referenced project. This study was performed in general accordance with our proposal number P95140346 (Revised), dated May 28, 2014. This report presents the findings of the subsurface exploration and provides geotechnical recommendations concerning the design and construction of foundations for the proposed project. Project Description The project site is located at 310 Gulf Stream Road in Fort Worth, Texas. It is planned to construct a new, two-story structure with an approximate footprint of 19,859 square feet. The building will have a structurally supported floor slab with a void space between the slab and underlying soil. We understand that the maximum column loads will be on the order of 120 kips. Fill materials have been placed at the site to develop the pad prior to our investigation. Field Exploration Description Subsurface conditions were explored by drilling two borings to depth of about 40 feet at the approximate location indicated on the Boring Location Plan on Exhibit A-1. The borings were performed using a truck -mounted drill rig. Samples of the soils encountered in the boring were obtained using thin -walled tube and split -barrel sampling procedures. The samples were tagged for identification, sealed to reduce moisture loss, and taken to the laboratory. The load carrying capacity of the bedrock in the borings was evaluated utilizing the Texas Department of Transportation cone penetration test. Field Togs of the borings were prepared by the drill crew. These logs include visual classifications of the materials encountered as well as interpretation of the subsurface conditions between samples. The boring Togs included with this letter represent the engineer's interpretation of the field logs and includes modifications based on visual evaluation of the Ter'acon Consultants, Inc. 2501 East Loop 820 North Fort Worth, Texas 76118 Registration No. F-3272 P [817] 268 8600 F (817) 268 8602 terracon.com Environmental 0 Facilities • Geotechnical • Materials Proposal for Geotechnical Engineering Services FWPD Aviation Administration Building Fort Worth, Texas May 30, 2014 Terracon Project Number 95145056 lierrecon samples. The boring logs are presented on Exhibits A-2 and A-3. General notes to log terms and symbols are presented on Exhibit A-4 Subsurface Conditions Fill materials consisting of dark brown and brown clays with limestone and concrete fragments were present to depths of about 12 to 17 feet in the borings. Tan and gray fat and lean clays with calcareous deposits and nodules and limestone layers were present beneath the fill materials to depths of about 22 and 23 feet. Tan limestone with clay layers was then encountered and extended to a depth of about 29 feet. Gray limestone with shale layers was then encountered in the borings and extended to the boring termination depths of about 40 feet. Groundwater was not encountered during drilling or at completion of drilling the borings. Discussion The proposed building can be supported on straight drilled shafts situated in the gray limestone that was present at a depth of about 29 feet in the borings. Drilled shaft design recommendations are provided below. Design Parameter Bearing stratum Allowable end bearing Allowable skin friction -compression Allowable skin friction -tension Minimum penetration to develop end bearing Penetration to develop skin friction Minimum center to center spacing to develop full skin friction Groups of 3 or more shafts spaced closer than 2.5 shaft diameters Recommendation Gray limestone 50,000 psf 7,500 psf 6,000 psf 2 feet or 1 shaft diameter, whichever is greater Depth below any temporary casing set in limestone 2.5 times the diameter of the larger shaft. Closer spacing may require some reduction in skin friction and/or changes in installation sequences and should be evaluated by Terracon. As a general reduction guide: varies linearly from the 100% value at a spacing of 2.5 diameters to 50% of the design value at 1.0 diameter. Should be evaluated on a case by case basis by Terracon. Alternative installation sequences may be needed to allow for a minimum of 48 hours concrete curing time, before installation of adjacent shafts. Minimum shaft diameter 18 inches Settlement Less than 1/2 inch for maximum Toads of 120 kips The drilled shafts may be subject to uplift as a result of heave in the overlying clay soils. The magnitude of these loads varies with the shaft diameter, soil parameters, and particularly the in - situ moisture levels at the time of construction. The shafts must contain sufficient continuous vertical reinforcing and embedment depth into the shale to resist the net tensile load. For Responsive Resourceful Reliable 2 Proposal for Geotechnical Engineering Services FWPD Aviation Administration Building Fort Worth, Texas May 30, 2014 Terracon Project Number 95145056 lierracon conditions encountered at the site, the uplift load can be approximated by assuming a uniform uplift of 1,800 psf over the shaft perimeter for a depth of 10 feet. The construction of all drilled shafts should be observed by experienced geotechnical personnel during construction to confirm: 1) the bearing stratum; 2) the minimum bearing depth; 3) that groundwater seepage, if encountered, is correctly handled; and 4) that the shafts are within acceptable vertical tolerance. Recommendations for drilled shaft construction are presented in the following table. Item Drilled shaft installation specification Top of shaft completion Time to complete Installation methods Groundwater control Recommendation Current version of American Concrete Institute's "Standard Specification for the Construction of Drilled Piers" ACI 336. Enlarged (mushroom -shaped) top in contact with the clays should not be allowed. Drilled shaft construction should be completed within 8 hours in a continuous manner to reduce side wall and base deterioration. Shaft excavations should be installed using dry methods. The concrete should have a slump of 6 inches plus or minus 1 inch and be placed in a manner to avoid striking the reinforcing steel during placement. Seepage was not observed in the borings, but could- be encountered during installation of the straight shafts, particularly during wet periods of the year. Rapid placement of steel and concrete may permit shaft installation to proceed; however, seepage rates could be sufficient to require the use of temporary casing for installation of the straight shafts. The casing should be seated below groundwater with all water and most loose material removed prior to beginning the design penetration. Care must then be taken that a sufficient head of plastic concrete is maintained within the casing during extraction. We appreciate the opportunity to be of service to you on this project. If you have any questions concerning this report, or if we may be of further service, please contact us. Sincerely, Terracon Consultants, Inc. e.4.00vk Texas Registration #3272 ®r0,9 O •�• T74oO44 .Oa e' Y, e• ;cS� 00 * 0 * : wle ce ,R YL C. P E D RAZA If 040 .33%104754. • Cheryl C. Pedraza, P.E. Project Manager cc: 4141 4/1 o 'SheCNsCO/ ° e� NALO\a Christopher W. Eddy, P.E. Geotechnical Department Manager jack.durham@fortworthgov.org Responsive Resourceful Reliable 3 0 (1) 0 J a) 1 L_ J 0 L 0 a 0 J : CAD\fort worth\2014\95145056.dw. THIS, DR4 r NG SHOULD NOSED SEPARATELY FROM ORIGINAL REPORT. Prod Mngr. DraAn By. Checked By: Approved By. CCP CDD CCP CWE Proed No. Scale: Date: 95145056 AS SHOWN 05130/14 Consulting Engineers and Scientists (Registrat'on No.: F-3272) 2501 EAST LOOP 820 N. FORT WORTH, TX 76118 PH. (817) 268-8600 FAX. (817) 268-8602 BORING LOCATION PLAN FWPD AVIATION ADMINISTRATION BUILDING 810 GULFSTREAM ROAD FORT WORTH, TEXAS EXHIBIT A-1 THIS BORING LOG IS NOT VALID IF SEPARATED FROM ORIGINAL REPORT. SITE: BORING LOG NO. BA PROJECT: FWPD Aviation Administration Building 310 Gulfstream Road Fort Worth, Texas o LOCATION See Exhibit A-1 U W c9 t DEPTH FILL - FAT CLAY (CH), with limestone fragments, dark brown and brown, stiff 12.0 FAT CLAY (CH), with calcareous nodules and deposits, tan, very stiff 16.0 with limestone layers at 15' LEAN CLAY (CL), tan, very stiff 19.0 FAT CLAY (CH), shaley, with calcareous nodules, tan and gray, hard 22.0 29.0 40.0 LIMESTONE, with clay layers, tan LIMESTONE, with shale layers, gray Boring Terminated at 40 Feet 5 CLIENT: City of Fort Worth Fort Worth, Texas SAMPLE TYPE 10— MIME 15- 20— STRENGTH TEST TEST TYPE 1.75 (HP) 3-4-4 N=8 4-5-8 N=13 8-11-4 N=15 4-7-11 N=18 w W z F- WZ ? Q� a�� o 1- 1- U 0<0 <0 0 Page 1 of 1 ATTERBERG LIMITS Z� �_ Ow LL-PL-PI 3.5(HP) I I 1 I I I 4.5+ (HP) I 15-17-19 N=36 25— ®I 100/0.5" 30— \I 100/0.25" 411 35— 100/1.25" 1 100/0.75" 1 I I I 1 Stratification lines are approximate. In -situ, the transition may be gradual. Hammer Type: Automatic Advancement Method: Notes: Dry Auger Abandonment Method: Borings backfilled with soil cuttings upon completion. WATER LEVEL OBSERVATIONS No seepage encountered during drilling Dry upon completion of drilling lierracon 2501 East Loop 820 North Fort Worth, Texas Boring Started: 5/25/2014 Boring Completed: 5/25/2014 Drill Rig: Driller: Doyle Project No.: 95145056 Exhibit: A-2 PERCENT FINES 0 0 0 u_ to 44r T cp J J 0 z 0 0 J 1- 0 CL 0 a w o' Boring Terminated at 40 Feet 0 2 0 o: LL 0 a. (0 Advancement Method: Dry Auger 0 zAbandonment Method: Borings backfilled with soil cuttings upon completion. 0 SITE: BORING LOG NO. B-2 PROJECT: FWPD Aviation Administration Building 310 Gulfstream Roan Fort Worth, Texas GRAPHIC LOG LOCATION See Exhibit A-1 DEPTH FILL - FAT CLAY (CHI, with limestone and concrete fragments, dark brown and brown, very stiff to hard 7.0 LEAN CLAY (CL), with calcareous deposits and limestone layers, tan, very stiff 29.0 LIMESTONE, with clay layers, tan LIMESTONE, with shale layers, gray z 2 0 SQ 40.0 WATER LEVEL OBSERVATIONS No seepage encountered during drilling Dry upon completion of drilling 5 CLIENT: City of Fort Worth Fort Worth, Texas • 10- 15— SAMPLE TYPE XI XI u. 4.5+ (HP) 14-12-10 N=22 5-10-12 N=22 37-28-35/2" 12-12-50/3" 20-15-7 N=22 20— X 4-8-11 N=19 25— iihk I 100/0.5" 30— 1161 100/0.25" STRENGTH TEST 1 6' 0 o:� w F-w 0 0 Page 1 of 1 AlTLERBERGIMITS L_' a z� oLL-PL-PI 35— 116..1 100/1" I I I I I I 4a� Lt 100/0.5" Stratification lines are approximate. In -situ, the transition may be gradual. Hammer Type: Automatic 11-effect:In 2501 East Loop 820 North Fort Worth, Texas Notes: Boring Started: 5/25/2014 Boring Completed: 5/25/2014 Drill Rig: Driller: Doyle Project No.: 95145056 Exhibit: A-3 PERCENT FINES GENERAL NOTES DESCRIPTION OF SYMBOLS AND ABBREVIATIONS SAMPLING 1 Auger Split Spoon Shelby Tube Texas Cone Grab Sample I I Macro Core Rock Core No Recovery WATER LEVEL a_ et Water Initially Encountered Water Level After a Specified Period of Time Water Level After a Specified Period of Time Water levels indicated on the soil boring Togs are the levels measured in the borehole at the times indicated. Groundwater level variations will occur over time. In low permeability soils, accurate determination of groundwater levels is not possible with short term water level observations. FIELD TESTS (HP) Hand Penetrometer (T) Torvane (b/f) Standard Penetration Test (blows per foot) (PID) (OVA) (TCP) Photo -Ionization Detector Organic Vapor Analyzer Texas Cone Penetrometer DESCRIPTIVE SOIL CLASSIFICATION Soil classification is based on the Unified Soil Classification System. Coarse Grained Soils have more than 50% of their dry weight retained on a #200 sieve; their principal descriptors are: boulders, cobbles, gravel or sand. Fine Grained Soils have less than 50% of their dry weight retained on a #200 sieve; they are principally described as clays if they are plastic, and silts if they are slightly plastic or non -plastic. Major constituents may be added as modifiers and minor constituents may be added according to the relative proportions based on grain size. In addition to gradation, coarse -grained soils are defined on the basis of their in -place relative density and fine-grained soils on the basis of their consistency. LOCATION AND ELEVATION NOTES Unless otherwise noted, Latitude and Longitude are approximately determined using a hand-held GPS device. The accuracy of such devices is variable. Surface elevation data annotated with +/- indicates that no actual topographical survey was conducted to confirm the surface elevation. Instead, the surface elevation was approximately determined from topographic maps of the area. SnREN GTH TERMS RELATIVE DENSITY OF COARSE -GRAINED SOILS (More than 50% retained on No. 200 sieve.) Density determined by Standard Penetration Resistance Includes gravels, sands and silts. CONSISTENCY OF FINE-GRAINED SOILS (50% or more passing the No. 200 sieve.) Consistency determined by laboratory shear strength testing, field visual -manual procedures or standard penetration resistance Descriptive Term Standard Penetration or Ring Sampler Descriptive Term Unconfined Compressive (Density) N-Value Blows/Ft. (Consistency) Strength, Qu, tsf Blows/Ft. Ve rY Loose Loose Medium Dense Dense Very Dense 0 3 4-9 10 - 29 30 - 50 > 50 i i 0-6 7-18 19-58 59 - 98 > 99 RELATIVE PROPORTIONS OF SAND AND GRAVEL pescriptive Term(sl of other constituents Trace With Modifier percent of Pry Weight < 15 15-29 > 30 RELATIVE PROPORTIONS OF FINES Desc intive Ter Isl. of other constituents Trace With Modifier Percent of Dry Weight < 5 5-12 > 12 Very Soft Soft Medium -Stiff Stiff Very Stiff Hard less than 0.25 0.25 to 0.50 0.50 to 1.00 1.00 to 2.00 2.00 to 4.00 > 4.00 Standard Penetration or Ring Sampler N-Value Blows/Ft Blows/Ft. 0 1 <3 2-4 4-8 8-15 15-30 > 30 GRAIN SIZE TERMINOLOGY Mgioc Comnpnenti of Sample Boulders Cobbles Gravel Sand Silt or Clay Term Non -plastic Low Medium High Particle Size 3-4 5-9 10 - 18 19-42 > 42 Over 12 in. (300 mm) 12 in. to 3 in. (300mm to 75mm) 3 in. to #4 sieve (75mm to 4.75 mm) #4 to #200 sieve (4.75mm to 0.075mm Passing #200 sieve (0.075mm) PLASTICITY DESCRIPTION Plasticity Index 0 1-10 11 - 30 > 30 lierracon Exhibit A-4