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Home My WebLink AboutContract 45454-A1 AMENDMENT NO. 1 to AGREEMENT for CONSTRUCTION ADMINISTRATION SERVICES for the POLICE AIR SUPPORT HANGAR at MEACHAM INTERNATIONAL AIRPORT STATE OF TEXAS § § CITY SECRETARY CONTRACT NO.!�Y�(A'11' COUNTY OF TARRANT § 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 27 th 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 1A, 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 OFFICIAL RECORD CITY O SECRETAIM FT- WRTH, TX J RECEIVED JUN ., 6 Police Air Support Hangar,Meacham International Airport Page 1 of 2 EXECUTED this the 001—clay of ,`2014, in Fort Worth, Tarrant County, Texas. Charles Willis and Associates, Inc. APPROVED: By: By: Cb6des A., Willis, AIA, NCARB Fernando Costa President Assistant City Manager APPROVAL R'MCOMMENDED: RECORDED n' C.1-- ", By: By: �7�j z Wiersig, PE KA a ry J. C" %—S) 0 Director, Transportation & Public 4morks Dept. City Secretary .%.7 -0 APPROVIWj RM AND LEGALITY: M&C R r Contract Authoriz By: Douglas W. Black Date: 00 000000 Assistant City Attorney R ORD OFFJCJAI,ii EC I effy"SECRETARY FT W0101111411 TX .............. Police Air Support Hangar,Meacham International Airport Page 2 of 2 t�►LL. A-��,ac+tM�r"All STRUCTURAL-" 7 ENGINEERIN ate. 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: 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 Willis,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. CALIAHAN 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: 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(fl May 30, 2014 Irerracon City of Fort Worth Architectural Services 410 W. 1 3th Street Fort Worth, Texas 761024616 Attn: Mr. Alfonso Meza : alfonso.meza@fortworthtexas.gov Re: Geotechnical Engineering Report PD Aviation Administration Building 310 Gulfstream Road Fort Worth, Texas Terracon Project Number: 9514505 Dear Mr. Meza: 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 Worth, Texas. It is planned to construct a new, two-story structure with an approximate footprint of 19,659 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 - . 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, d 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 logs 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 logs included with this letter represent the engineer's interpretation of the field logs and includes modifications based on visual evaluation of the Derr;mmn Cons dt nts, lncw 2501 East Loop 820 North Fgtt Wwlh, texas 761.18 Re l traUen too.F-3272 P 18,17`1 ir68 0600 F !81 71 268 8602 tarrecon.com . Environmental JIB Facilities Geotechnical Materials Proposal for Geotechnical Engineering Services FWPD Aviation Administration Building a Fort Worth,Texas 1rerracon May 30, 2014 111111111! Terracon Project Number 95145056 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 Recommendation ............ ....... Bearing stratum Gray limestone Allowable end bearing 50,000 psf -.-......................... ..............................---............................-.................. Allowable skin friction-compression 7,500 psf ................ .................. ............................. ............................................ Allowable skin friction-tension 6,000 psf .......... ......................-111..........--.........----...........I...... Minimum penetration to develop end 2 feet or I shaft diameter, whichever is greater bearing ........... ....... ......... Penetration to develop skin friction 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 Minimum center to center spacing to in installation sequences and should be evaluated by develop full skin friction 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. Groups of 3 or more shafts spaced Alternative installation sequences may be needed to allow closer than 2.5 shaft diameters 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 form loads 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, sail 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 Responsivew Resourceful a Reliable 2 Proposal for Geotechnical Engineering Services FWPD Aviation Administration Building iiu Fort Worth, Texas Ire rracan May 30, 2014 ow Terra con Project Number 95146056 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 Recommendation ........................... ............................_.-.......... ...... .......... Drilled shaft installation Current version of American Concrete Institute's "Standard Specifi cation for specification the Construction of Drilled Piers"ACI 336, ..................11-...... .................____.................... Top of shaft completion Enlarged (mushroom-shaped) to in contact with the clays should not be allowed. .................... ................ ........................_................. Time to complete 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 Installation methods should have a slump of 6 inches plus or in 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 Groundwater control 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. OF Texas Registration#3272 ...... .................. RYL C. ef 44 r® om R 0• ............. 104764.®.®Ac W Cheryl C. Pedraza, P.E. 4W 1W ChristoperW. Eddy, P�E� Geotechnical Department Manager Project Manager 111111%�\\\VNI A L cc: jack.durham@fbrtworthgov.org Responsive m Resourceful m Reliable 3 ......................... r / P/1 i r %% / 22/ O 4Y h O J C I �f1 O 6 T O J e7+ +T3 O N W fJ C9 O z j" a� M ifs 6 a` O %f CCP �w 9514 EXHIBIT BORING LOCATION PLAN CDD AS SHOWPJ — Min ` uffln =and cion D AVIATION ADMINISTRATION BUILDING ®r q sot EMI'uroP®row. FORT WMN.Tx 76118 810 CvUL�ST'FtE AD A-1 CWE PH.(Bin rAmm FAX,(61n FORT'WORTH,T BORING LOG NO. B-1 Page 1 of 1 PROJECT: FWPD Aviation Administration CLIENT: City of Fort Worth Building Fort Worth,Texas SITE: 310 Gulfstream Road Fort Worth,Texas LOCATION Sm Exhibit A®1 p STIR TE A E ssRG W 10 !fi a N aPI 0 <c C o c7 DEP v� " a FILL d FAT CLAY(CHI,with limestone fragments,dark 1.75 HP brown and brown,stiff -4 N=8 _. N®13 ®..._.. 8-11-4 _... N=15 -. 4-7-11 1 12.0 FAT CLAY(CHi,with calcareous nodules and deposits, tan,very stiff 16.o with limestone layers at 1 ` LM CLAY(CLl,tan,very stiff 19.0 CL FAT CLAY(CHI,shaley,with calcareous nodules,tan q and hard 1517-19 —_ 22.0 g ya -. N=38 y LIMESTONE,with clay layers,tan 0 2 10010.5°° 29.0 LIMESTONE,with shale layers,gray 3 100/0,25" 4 o c� 0 100/1.25„ 0 w e� ae 0 40.0 � 100/0.75" Boring Terminated at 40 Feet S2 1K 0 Stratifi on lines are appraxln e.In-situ,the transition may be gradual. Hammer Type: Automatic a Advancement Meth: Notes: Dry Auger q 0 Abandonment ° Borings bacIdIlled with sail cAnge upon completion. ° WATER LEVEL OBSERVATIONS . Baring n 2 0lExhlbit Boring : 14 —ft seepage encourntefed during drilling Ddfl Rig: tler:Dry upon compledw of drilling 2 0 t East t p set N h fort orth,Texas Proled .:95145058 A-2 BORING LOG NO. B-2 Page I of 1 PROJECT: FWPD Aviation Administration CLIENT: City of Fort Worth Building Fort Worth,Texas SITE: 310 Gulfstream Road Fort Worth,Texas S ATTERBERG LOCATION Exhibit A-1 CO as liM"s W UJ F eat u WQ:w.a z LL® -PI v a 0 ' y H cx FILL d FAT CLAY(CH),with limestone and concrete 4. +(H } fragments,dark brown and n,very stiff to hard 14-12-1 tlm _N=22 .. 5 5-10-12 37-28-35/2" 12-12-5013" 1 _ 15 N=22 17.0 LLAN CLAY(CLI,with calcareous deposits and limestone layers,tan,very stiff 2 4-8-11 N=19 y 23.0 LIMESTONE,with clay layers,tan 2 10010.5" �...� 29.0 LIMESTONE,with shale layers,gray 0 10010.25" 0 t3 0 3 ud c� 0 40.0 .5" Boring Terminated at 40 Feet c� 0 0 stratification lines are approximate.in-situ,the transition may be gradual. Hammer"type: Automatic vWt Advancement Method: IL Dry Auger z Abandonment m Borings Iled with soil cuttings upon completion. e� WATER LEVEL OBSERVATIONS � ---.------ww---. Boring 14 Boring : 14 -� Ado eracoern dt�rinq drfll�ng rerracan _._ .� Drill Rig: Driller e DW upon completion of dnllerg ,.�� _ 2501 East Wnp 820 North f olt Wodh,Pemis Project .:85143058 Exhibit: A-3 GENERAL NOTE D�SCRI{sTIQN QF Sit IM ABBREt/tATIQNS water initially (HP) Hand penetrometer Encountered Auger Split on w r Level After a ( T � Sp Pert Time 0 w Water fl Period of Ti F (bit) Standard Penetration rn T (blows per toot) a illy Tub f° J Water levels indicated 'I boring F` (Pro) PhoWloniaation Detector 0: logs are the levels measured in the ILI borehole at the times indicated. r j (OVA) Organic Vapor Analyzer Texas Co Rik Core 4 Groundwater level variations °b r LL over time.In low permeability soils, (TCP) Tema Cam Penetrometer accurate delortnination of groundwater levels is not possible with short term ter level observations. Grab Sample No Recovery ESC � T(V S IL CLASSIFICATION N 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 ing to the relative proportions based on grain size.In addition to gradation,coarse-gained soils are defined on the basis of their"ace relative density and fine-grained soils on the basis of their consistency. LOCATIQN ASV® LEVAI QN NOTES Unless otherwise noted,Latitude and Longitude are approximately determined using a hand-held GS 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. RELATIVE DENSITY OF COARSE-GRAINED SOILS CONSISTENCY OF FINE-GRAINED SOILS (More t retained on No.200 sieve.) (50%or more passing the Nm 200,31ove.) Density determined by Standard Penetration Resistance Consistency determined by laboratory shear strength testing,field Includes gravels,sands and silts. visual-manual procedures or standard penetration resistance V) Descriptive Term Standard Penetration or Ring Sampler Descriptive Term Unconfined Compressive Standard Penetration or Ring Sampler 2 (Density) N°Vale BlowstFt. (Consistency) S N-Value 81o1 ix Blows/FL BlwslFt VeryLoose 0-3 0m5 very Soft less than 0.25 0-1 �3 Loose 4-9 'r.18 Soft 0.25 to o. 2-4 3-4 z Medium UJ nse 10,29 19-58 Medium-Sriff 0.50 to 1.00 4..S 5.9 Dense 30-50 59-98 Stiff 1.00 to 24 8..15 10-18 Very e >50 99 very Stiff 2.00 to 4.00 15..30 19..42 Hard >4.00 >30 >42 �IATI �'jQ O ND D Gtt/1VEL GIFtAJN s! TEIBttA) OLOGY Deseri ve Termrsl p�(tlr t:a ent Pa cle Slxe of°Ebel constltu®rite Dry Weight Trace <15 Boulders Over 121n.(300 trim) With 15-29 cobbles 12 in.to 3 In.(300mm to 75mm) Niodifier s 30 Gravel 31n.to#4 sieve(75rnm to 4.75 ) Sand #4 to#200 sieve(4.75mm to 0.07 Silt or clay Passing#200 sieve(0.07 ) RE TINE OP ONS FINES E A3TICITY DESCRIPTION CIe$rriotivo Tormfsl Plasticity index of otltor constituents Dr+e VYoiaht Non-plastic 0 Trace <5 LOW 1-10 With 5-12 iu 11-30 Modfifier >12 High lrerrac.on exhibit A-4