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HomeMy WebLinkAboutContract 51435-CO2 FORT WORTH City of Fort Worth CSC No. 51435-0O2 Change Order Request P*d Narnal Village Creek INRF Lkluld Biosolids Storage Tank City Sec No. 51435 I?rt1jWNo.(s)j P266/56007 07CSF30WF60 City Pro].No. CO2669 R*d Desc"orr L u;Mosoid Slorege Tank et VCWRF Caftdw.f Crescent Constructor,Inc. Grange Order: Date: 411412020 City Project Mgr.1 Selavash IAr City Inspector: Nathan Gray Phone Number 817-39241W Ptwne Ndrrt 817-91.0629 Dept. Sewer Totals Contract Time(Calendar days) Original Contact Amount 6,437,000.00 $6,437,000.00 540 Extras to Dale $98,800,00 $98,800.00 21 Credits to Date Pending Change Orders On M&C Process) Contract Cost to Date $6,535,800.00 $6,535,800.00 561 Amount of Proposed Change Order $0.00 $0.00 077 Revised Contract Amount 6,535,800.00 6,536,800.00 638 Original Funds Available for Change Orders $294,000.00 $294,000.00 Remaining Funds Available for thisCO $195,200.00 $195,200.00 Additional Funding Of necessary) CHANGE ORDERS to DATE(INCLUDING THIS ONE)AS%OF ORIGINAL CONTRA CT 0.59% MAX ALLOWABLE CONTRACT AMOUNT(ORIGINAL CONTRACT COST+25%) $8,046,250.00 JUSTIFICATION(REASONS)FOR CHANGEE ORDER 1.This Change Order was City directive to add manways by cutting and welding to the existing steel tanks for dewatering(Field Order#2). 2.Install concrete pads for the placement of the Landia Air-Jets on the existing tanks(Field Order#1). 3.Install of the cutoff blocks for the pipe trenches to help prevent back weeping of the pond water(Proposed Construction Modification#2 and RFI#33). 4.The credit to the City of$32,000 is from the removal of the slurry wall from the drawings(Proposed Construction Modification#1 and RFI#24). 5.The proposed contract time comes from 7 days for the additional work mentioned and 70 days due to inclement weather through March 31,2020. Staff concurs with the Contractor's cost breakdown as attached. Additional detail can be found in the fallowing pages. It Is understood and agreed that the acceptance of this Change Order by the contractor constitutes an accord and satisfaction and represents payment In full(both time and money)for all costs arising out of,or incidental to,the above Change Order, Contractnes Company Name Contractor Name Contractor Signature Date Crescent Constructor,Inc. Ryan Glanz,P,.E. Ryan Glanz 0 4/14�2O Inspedur Date Pra)ect Manager Dale Nathan Gray n 4/1 712 0 2 0 Seiavash Mt 9z.�, 4/17/2020 Alrector star Date C mtru don Mana Stanled: Date H o or or 'x, Apr21,2020 04/14/2020 Chris Harder,P.E. • S. Alex Visotski.P.E. Assistant City Aim date Assistant Ma er Date Doug Black :`«:;,." Apr 27,2020 Dana Bughdoff e Apr 27,2020 Cound Action Ifi e u M&C Number M&C Date Approved ��� F"P,-F WC4 P,-Y City of Fort Worth -f Change Order Additions Project Name Village Creek WRF Liquid Biosolids Storage Tank City Sec No. 1 51435 Project No.(s) P266/56007 070SF30WF80 I I City Proj.No. CO2669 Project Village Creek WRF Liquid Biosolids Storage Tank Description Contractor Crescent Constructor, Inc. Change Order: 0 Date: 4/14/2020 City Project Mgr. Seiavash Mir City Inspector Nathan Gray ADDITIONS DESCRIPTION DEPT Qty Unit Unit Cost Total 2.1 Install Manway(Field Order 42)(+7days) 2.00 EA $10,000.00 $20,000.00 2.2 Raise Landia Concrete Pads(Field Order#1) 4.00 EA $2,000.00 $8,000.00 2.3 Install Concrete Cutoff Blocks in pipe trenches(RFI 433) 16.00 CY $250.00 $4,000.00 2.4 Removal of Slurry Wall 1.00 LS -$32,000.00 -$32,000.00 2.5 Weather Events through March 31,2020(+70 days) 1.00 LS Sewer Page 2 of 4 Additions Sub Total Contract Compliance Manager By signing I acknowledge that I am the person responsible for the monitoring and administration of this contract,including ensuring all performa7to/4 and reporting requirements. /Ir-- D Signs ure Tony Sho Iola Name of Employee Assistant Water Director Title f-ORr ATTEST: M11UV Mary J. Kayser City Secretary , OFFICIAL RECORD CITY SECRETARY FT. WORTH,TX 2560 Technology Drive 9400 Plano,TX 75074 CONTRACT MODIFICATION REQUEST: PCM-FWO#01 & #2 PROJECT: VILLAGE CREEK BIOSOLIDS TANK DATE: 03/27/20 PROJECT NO. CO2669 ATTENTION: CITY OF FORT WORTH 1000 THROCKMORTON STREET FORT WORTH, TX 76102 ATTN: SEIAVASH MIR Attention: The following change in contract on this project is proposed: A breakdown of cost SHALL be attached. Work shall not connnence until authorized by the OWNER. Description of the Proposed Change & Clarifications Pricing for the following (1) Increase size of 4 EA concrete pads for Landia Air jet system to sit on. Larger pads will raise the inlet piping elevation to delay grit intrusion into the Landia mixing pump system (See field work order#1 02/21/20) = $8,000 total ($2,000 Ea) (2) Cut in new Manways on existing steel tanks for sludge grit removal by plant (1 EA on 0.8 MG Tank& 1 EA on 0.5 MG Tank) (See field work order#2 03/16/20) _ $20,000 ($10,000 Ea) TOTAL AMOUNT $ 28,000 Ryan Glanz Cescent All work shall be in accordance with the terms,stipulations,and conditions of the original Contract Documents. If the work herein provided for is Approved by Change Order,the time of completion will be: Increased By 7 ***Calendar Days Decreased Unchanged 11 ACCEPTED City of Fort Worth Date ❑ REJECTED CHANGE ORDER SUMMARY Front Sheet VILLAGE CREEK BIOSOLIDS TANK CHANGE DESCRIPTION: CONTRACT MODIFICATION REQUEST# PCM-FWO#01 &#2 Job#: 2018-03 Description Labor Material Equipment Subcontract Total DIRECT COSTS 3,500 4,146 2,616 12,480 22,742 LABOR BURDEN&FRINGES 55% 1,925 1,925 SUBTOTALS 5,425 4,146 2,616 12,480 24 667 CONTRACTOR MARKUP 15% 1,828 CONTRACTOR MARKUP 5% SUBS 624 BONDS&INSURANCE 3%1 814 68 TOTAL - - - 28,000 CLARIFICATIONS: 1 2 3 4 Total Unit Unit Unit Unit Total Total Subs Description Qty Un Labor Mad Equipment Labor Mat'I Equipment 1 LABOR - Mechanical Foreman 16.0 MH 40.00 640 Field Crew----1.5 Days x 5 men 60.0 MH 2O.00 1,200 Operators ---1.5 Days x 1 men 12.0 MH 25.00 300 Weld Crew---2 Days x 3 men 48.0 MH 2O.00 960 Crane Operators --2 Days x 1 men 16.0 MH 25.00 400 MATERIAL - Concrete(3 CY each x 4) 12,0 CY 128.00 1,536 Wood Forms,bracing,etc 12.0 CY 50.00 600 Misc Pipe Material/Tools/Safety 72.0 MH 1 5.00 360 Rebar 150 NCY x 12) 1,800.0 LBS 0.50 900 Welding Supplies(Rods,safety,etc) 1.0 LS 750.00 750 EQUIPMENT(Daily/Weekly!Monthly)Cost (Fuel,Oil,Grease,&Maintenance Included Backhoe CAT 416E(COE) 16.0 HR 21.07 337 Crane(Position&Set Manway) 16.0 HR 142.42 2,279 SUBCONTRACTORS - Manway Installation(Welding Service) 1.0 LS 8,500.00 8,500 Manway Stiffener Plate Installation 2.0 EA 350.00 700 Coat New Manways Painter Costs) 1.0 LS 3,000.00 3,000 Material Testing&Inspection(1%) 1.0 LS 280.00 280 3,500 4,146 2,616 12,480 Job:Biosolids GST Item: 1/1 Stantec Consulting Services Inc. ® Stantec 12222 Merit Drive Suite 400,Dallas TX 75251.2268 March 16,2020 File: 224701011 Attention: Ryan Glanz 2560 Technology Drive,Suite 400 Plano,TX 75074 Dear Mr. Ryan Glanz, Reference: City Project No. CO2669 Village Creek Water Reclamation Facility Liquid Biosolids—Field Order No.2 Bottom Line Up Front(BLUF): No change in schedule is anticipated. The Owner requested a proposal for the cost of two (2)additional manway assemblies at the existing steel tanks to facilitate dewatering operations. Current Contract Requirement: • Sheet 1 M-1 does not include proposed additional manway openings on the existing tanks for dewatering. Existing Condition: • Plant operations indicated the existence of a sludge blanket about 18 to 24 inches from the tank bottom. Requested Change: • At the City's request,to aid in the maintenance and dewatering of the existing steel tanks, the Contractor should provide a 30-in manway at the locations shown in the attached documentation. See attached detail for reference and provide a similar or equal product guaranteed to meet the hydraulic forces of a full tank. The bottom of the assembly should be between 36 to 48 inches above the finished floor(approximately at elevation 477.35 to 478.35). Verify locations with the Owner. Coordinate welding requirements with the manway supplier and submit product details for review. Root Cause of the Change: • Operations are unable to remove the settled sludge solids in the existing steel tanks. Dewatering access should be provided for Operations to remove these solids. Cost Evaluation: Costs associated with the two 30-inch manway assemblies are anticipated and will be provided by the Contractor. Design with comntunily in mind March 16,2020 Ryan Glanz Page 2 of 2 Reference: City Project No.CO2669 Village Creek Water Reclamation Facility Liquid Biosoltds—Field Order No.2 Concurrence, Recommendation and Justification: We have reviewed the items described herein and recommend acceptance of these items pending review of the price proposal for the reasons stated in the Root Cause of the Change section of this letter. Attachments: Sheet 1M-1, 30-inch Manway Detail Regards, Stantec Consulting Services Inc. Javier Cantu Senior Project Manager Phone: 713 403 1615 Javier.Cantu@stantec.com c. Seiavash Mir,Farida Goderya,Steven Nutter,Nathan Gray Design wilh communily in mind v cam...-ne �nrsTnn•.w'_tu+.en u...yYa�» _ mie-�o�a:.v �FT mTAO—� m°- q <u 0 j o 3 m a i Hz g Sao�v r o o�- El fu c CD x 0 .a yin�m�•N+ �f �2032 s m m < d..c 3 0-ty I. g � o 0000 g H9 i ano 0 m m o 3 Q8 i 3 0, v � ' ' —r-- RE F n P� \ 9R =J 3 o � - zN F A,\ , o slip f a� — -lo - H Nzpa2 ® g mo of �m g qq- 1. �m =u o na— 3 ' Al»•� ��y m 0IF- 00 0 0 0� o nO.000 f J — w<om 0 0 �._3 `m ol D N m — 4 g� r n n u ... m T g z > m y F o 'M H Gig M. n T 10 =❑ mACSC5 A A O m m�Oi E. FAO ppri fmTl °g9z x aS° S2m O n oG �c i >>m S a o $ a zooy -iy m yo o ° O s� A A F AN D F5O O >r�y U1 o SS R� z aF RAINopc p o G1A S AHo pqn� In° o 2 ° a° 1 O � C . Z H n °oN" m �N � a 3 p co � N cc � � _' � 1�r�11t�r11Fz .. O � N So S42 m o n r m � m -Aix z � rczi� m a C—N9 GZ7 OW � 9 �s�jNm m z a N a 'riOz�a � N r x m N m A = mw of z m N = ; v) a a � `No zNDO z m A O o rcn tnn o N z N pZEn o m � o z cmn r�i a c� � o a c-� N C O p O 0 0 1/4 � m .w � o � a a. mCEI I �\ / i N — m '71 C O --II---- O .gyp. 00 as = oED r � _ N V Z c C N m a r m m o a s z , o o ZOW From: Dale's Welding Services 3/25/20 Address: 9824 County Rd 307 Estimate Terrell, TX 75161 Phone: 214-507-9569 e-mail: dalesweldingsvc@sbcglobal.net To: Crescent Constructors Attn: Ryan Glanz Phone: 214-783-8007 e-mail: ryan.glanz@crescentconstructors.com i CITY PROJECT NO. CO2669 VILLAGE CREEK WATER RECLAMATION FACILITY LIQUID BIOSOLIDS— FIELD ORDER NO, 2 Description of work to be performed: 1). Furnish and install a new 30" Bolted Manway for the 0.5 MG and the 0.8 MG Tanks as per drawing by Containment Solutions. Per Manway: $ 4,250.00 Total for both Manways: $ 8,500.00 Note: Quote includes all labor, equipment, fabrication costs, materials, welding certificates, and the required insurance certificates. Stantec consulting Services Inc. ® Sta ntee 12222 Merit Drive Suite 400,Dallas TX 75251-2268 February 21,2020 File: 224701011 Attention: Ryan Glanz 2560 Technology Drive,Suite 400 Plano,TX 75074 Dear Mr. Ryan Glanz, Reference: City Project No. CO2669 Village Creek Water Reclamation Facility Liquid Biosolids—Field Order No. 1 Bottom Line Up Front(BLUF): No change in schedule are anticipated a proposal is being requested for the price of pump pedestals on the landia air jet system. Several modifications were requested to facilitate field application of the proposed equipment and to account for unforeseen conditions. Current Contract Requirement: • Item No. 1: Contract Clarification (RFI#38)Sheet C-5, Points 15&26, the connection to existing tank is indicated below grade 469.50FT. • Item No.2: Sheet 1 M-1, Center line of inlet to Landia air jet is located at 15-inches from tank floor and outlet at 48-inches from tank floor.With a contract difference of 33-inches.The air jet is not connected to a pedestal. Existing Condition: • Item No. 1: Elevation 469.50 is below grade at the tank foundation and can not tie in at this location. • Item No. 2:At the February 21s', 2020 construction progress meeting, plant operations indicated that the sludge blanket appeared to be about 24 inches from tank bottom. Requested Change: It . 1• I ifi io -e v 'on 69 0 s ee - s at t c er n f ' e ut ' e al v It. ro 'de ve a pi e i et t to s' it to a is ' g et in 'ca d • Item No. 2: Apply detail B on page 2M-2 to the existing tanks so as to provide pump pedestals such that the intake pipe elevation of the Landia air jet system is 36-inches from center of pipe to tank floor(Approximately 477.35) Design with communily in mind February 21,2020 Ryan Glanz Page 2 of 2 Reference: City Project No.CO2669V11lage Creek Water Reclamation FacilityLiquid Biosolids—Field Order No.1 Root Cause of the Change: m o. yriXa* oe a , e Giisises�tp7e/p6ut tl er to C- in ca rifi e • Item No. 2:At the February 21s', 2020 construction progress meeting, plant operations indicated that the sludge blanket is thicker and experiences rag accumulation at that low of an elevation. To facilitate operations and help prevent clogging of the air jets it was requested the air jets be raised and put on a pedestal. Cost Evaluation: Costs associated with extra concrete for the pump pedestals are anticipated and will be provided by Contractor. Concurrence, Recommendation and Justification: We have reviewed the items described herein and recommend acceptance of these items pending review of the price proposal for the reasons stated in the Root Cause of the Change section of this letter. Attachments: Sheet G-8, C-5, 1-M1, 2M-2 Regards, Stantec Consulting Services Int.. �. 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Nmu g ?R �S' N z Pg 1 �e o a 2560 Technology Drive 9400 Plano,TX 75074 CONTRACT MODIFICATION REQUEST: PCM-RFI 33.1 PROJECT: VILLAGE CREEK BIOSOLIDS TANK DATE: F 12/20/19 PROJECT NO. CO2669 ATTENTION: CITY OF FORT WORTH 1000 THROCKMORTON STREET FORT WORTH, TX 76102 ATTN: SEIAVASH MIR Attention: The following change in contract on this project is proposed: A breakdown of cost SHALL be attached. Work shall not commence until authorized by the OWNER. Description of the Proposed Change&Clarifications Pricing for the following (1) Install cut-off blocks in the pipe trenches (16" OF (PV05), 12" DSL (PV03), and 3" FEC (PV02))to help minimize any backweeping (RF133) of water from the pond into the pipe bedding (2)Additional cut-off blocks installed to a total of 16 CY TOTAL AMOUNT $ 4,000 Ryan Glanz Cescent All work shall be in accordance with the terms,stipulations,and conditions of the original Contract Documents. If the work herein provided for is Approved by Change Order,the time of completion will be: Increased By 0 '**Calendar Days Decreased Unchanged ACCEPTED City of Fort Worth Date ❑ REJECTED CHANGE ORDER SUMMARY F77Front Sheet VILLAGE CREEK BIOSOLIDS TANK CHANGE DESCRIPTION: CONTRACT MODIFICATION REQUEST# PCM-RFI 33.1 Job#: 2018-03 Description Labor Material Equipment Subcontract Total DIRECT COSTS 680 2,128 169 - 2,977 LABOR BURDEN&FRINGES 55% 374 1 1 374 SUBTOTALS 1,054 2,128 169 - 3,351 CONTRACTOR MARKUP 15% 503 CONTRACTOR MARKUP5% SUBS - BONDS&INSURANCE 3% 116 31 TOTALI 4,000 CLARIFICATIONS: 1 2 3 4 Total Unit Unit Unit Unit Total Total Subs Description Qty Un Labor Mat'I Equipment Labor Mat'I Equipment LABOR - Mechanical Foreman 4.0 MH 40.00 160 Field Crew----0.5 Days x 4 men 16.0 MH 2O.00 320 Operators ---0.5 Days x 2 men 8.0 MH 25.00 200 MATERIAL - Concrete(5 CY min) 16.01 CY 113.00 1,808 Wood Forms,bracing,etc 5.0 CY 50.00 250 Misc Pipe Material/Tools/Safety 28.0 MH 2.50 70 EQUIPMENT Daily/Weekly/Monthly Cost Fuel,Oil,Grease,&Maintenance Included Backhoe CAT 416F(COE) 8.0 HR 21.07 169 SUBCONTRACTORS - 680 2,128 169 0 Job:Biosolids GST Item: 'ON ON,S1V�1�01NOtfY15 ;P fil N Z o a � r�0 II II II m o D VARIES z m z � o °°41 D2 m mN o = m D - -— - - - _ -- O fn Om -I Z U1 El. m m m� Tr -- -- o il8� rn 6° a m(Dr �1 MIN, z o m 00 zzzW > z cn o =- co 0 F9 � z 31 Y' Z S ✓ VARIES I D� 2� D i i ✓t�%' 4 o O - N v' o p n = 4" MIN. 1 P Cil 00 o p zz d 0 c11 2 �1 O o Ul k' n O n z P I -- REQUEST"FOR INFORMATION Stra ntec (RF133) PROJECT NAME: MQWRE LIQUID BIOSOLIDS STORAGE TANKS #:CO2669 OWNER: FORT WORTH CONTRACTOR: CRESCENT -- ENGINEER: ST NJEC DATE: 11/06119 REFERENCE DATA: Specification Section# Page# Paragraph Drawing#C-5 RFI Description: Pipe Trench Cutoff Block CONTRACTOR REQUESTS (circled): Information Interpretation Clarification Described below or in the attached material referenced below: See attached. CONTRACTOR'S PROPOSED SOLUTION: See attached. REQUESTED BY: DATE: ENGINEER'S RESPONSE (circled): Information Interpretation Clarification Described above or in the attached material referenced: Stantec agrees that the concrete cutoff blocks in the pipe trenches could help prevent potential back weeping.The Contractor shall provide a cost estimate for the cutoff blocks for our review prior to approve the suggested design modification. RESPONSE BY: Alex Visotski M. Ena P. Ena (Canada) DATE: 11/07/19 Owner: City of Fort Worth Date: XX/XX/XXXX Contractor: Crescent Constructors, Inc. Project No.: CO2669 Project Village Creek Water Reclamation Facility— Name: Biosolids Storage Tank RFI No.: 33 Spec/Dwg. RFI Title: Pipe Trench Cutoff Block Reference: C-5 (Attached) Information or Interpretation and Reason Requested See attached sketch of a possible addition of concrete cutoff blocks in the 16"Overflow Pipe trench, 12"inlet line pipe trench, and 3"ferric line pipe trench to prevent back weeping of pond water thru the pipe trenches and holding water. ---Proposing to use funds from the slurry wall deletion to install the 3 pipe trench cutoff blocks. If the addition of pipe trench cutoff block RFI is approved, pricing will be provided. Authored By: Date Rg Submitted: 11/06/19 Response to Request: Click here to enter text. In the event, Contractor believes the RFI response does or will cause a change to the requirements of the Contract, Contractor shall immediately give written notice stating that Contractor considers the response to be a Change Order. Firm Name: Date Click here to enter text. Returned: XX/XX/XXXX Signature Printed Name: END OF DOCUMENT ll,:Gt•.,Wefmlfl�ll.\nla_r.SGN ,,.jvkn.n Flf Dia Y.Yf JSJ11011•YS',Jiu � 7.(• 41 la _ ;_ €R� \ __ 4•v— I 92 .\ N AQ3mN N; —.._..----------••--•-------•-----------•— — 1/ mE SHF f i m �F HAMB r I R < m am -�+'mF r v R I III I ',I M V R c I O r;$ga z a r o I mg I - x a - s�Sg� 474 dvZ is R n PG) VIA Ad € -- I ovala� v m o3 v= mvFnn �! - Ii ti `', I i a zP I IV w— —na— +�e DD a $zt=9=i10 mAm2 N gg s f fi 3 s a s s gg s a e s s a s a s e s x a z aoxocon ,a F zzo x �' �wAA? `�� $ °<mp�"mc5F gg. =gff"o" s 5 � �9 �� g�9� a��3c - e� c � ���� -� � s"�_ � <�a!H �`�'mm���-•�' "Rxa�r<„ xm m P� �2 ' ° r mmv �vm. -'-. <R nmmPnto oga o ��oHgp �gq N n�p3i �1 C Y Y al�on�� �2 (1 - UR' T�<c ;CN F = 3m>Fm <mF 9� aF 2bmiz O�z]�6 i m P x x .. gss gg �gxxe x Esgi ga �_x "s _ 'O oN ;2�$vP$vc�Boy Z '3 -m-1 no$ ga � eayi� � 65aes:a§Ia§k ;§: mgb:EE_3a�ns36Ee6aS n z poalloPi�000n3m �pp3o <�p��m� � z eFm'XmHMI g° m a"�•"+g 'ocF ? �O mzx.9moR�$��"� N 95 € c9 S s : � = 9495aassca as a § g :t a39a§ffig £ o� mr cp °PAP X� f�N�AN��o7ii3� 25F`:� g N k3 ° esk SSakkkkkkk6E34 eks8 §§ Sx k E9I3k.'.v �9gv Ek c m c � iH LA ov�:+�,za �a § 5a m-+ a i'"o$o$< gmm��a "sraa�8s��" $$?§$k i ?' oA��sitg u>.- p Ao$ =gym s ma v!E 5s z2 �wilm Oo o+ ' N REQUEST FOR INFORMATION Stra ntec (RFI 24) PROJECT NAME: VCWRF LIQUID BIOSOLIDS STORAGE TANKS #: 02669 OWNER: FORT WORTH CONTRACTOR: CRESCENT ENGINEER: STANTEC DATE: 04/23/19 REFERENCE DATA: Specification Section#31.30.00 Page#14 Paragraph 3.10 Drawing#C-2 &4 Detail description: Slurry Wall CONTRACTOR REQUESTS (circled): As an option to save money on the project and provide a credit back to the City for the deletion of the slurry wall, Crescent and the City have asked Preload if the Slurry Wall show on the south side of the Tank (C-2) is required for Preload's tank design. See attached 04/22 email from Henley-Johnston (HJ) (Preload's geotechnical designer)with a few questions. (1) HJ is asking for clarification on Stantec's original design intent for the slurry wall use. (2) HJ notes the use of the slurry wall could introduce an additional slope failure plane (3) HJ notes the use of the slurry wall will not limit infiltration of water from the lagoon into the tank subgrade If the slurry wall can be deleted by Stantec design, Crescent could provide a credit to the City. CONTRACTOR'S PROPOSED SOLUTION: REQUESTED BY: DATE: ENGINEER'S RESPONSE (circled): Information Interpretation Clarification Described above or in the attached material referenced: (1) HJ is asking for clarification on Stantec's original design intent for the slurry wall use. Stantec's design of the slurry wall was intended to keep groundwater on the lagoon side of the slurry wall from moving laterally to the subgrade of the tank because fluctuating water levels may result in expansion and contraction of the soils beneath the imported soils under the tank. Section 9.3 of the Geotechnical Report by HVJ, included in the contract documents, cautions that water infiltration migrates into subgrades such as the 5MG tank, and HVJ and Associates suggested features to prevent"lateral migration of water such as cutoff wall installed to a depth below the pavement" . (2) HJ notes the use of the slurry wall could introduce an additional slope failure plane Please provide sketches and calculations to help Stantec understand the concerns for a slope failure as the wall is 15' from the top of the slope, not at the top of the slope as suggested in the e-mail from HJA on 22APR. (3) HJ notes the use of the slurry wall will not limit infiltration of water from the lagoon into the tank subgrade. The intent is not to prevent infiltration of water as this is impossible; surface runoff is one source of infiltration; the pond is another (lateral infiltration). Assuming (conservatively) that pond water levels are constantly high, infiltration from the pond could be continuous, while surface runoff infiltration would only occur during rain events. Additionally, the pond is meant to serve as emergency overflow storage of the solids tank contents therefore limiting the infiltration of the solids retaining water is desirable. Stantec agrees that the design of the slurry wall is a conservative approach and its requirement is subject to Preload's tank design parameters. Contractor shall provide calculations indicating floatation due to groundwater is not a concern, along with and engineer's justification for removal of the slurry wall indicating that such actions will not have any adverse impacts on the tank. Include an opinion of probable credit to the City with the justification for further review and approval prior to developing a CMR. RESPONSE BY: JAVIER CANTU, PE DATE: 4/30/2019 I se.cv,.-w.armvrmnava=o��w rrro.w x�uuHu-m"rvu IIII YSY... 3 . a IP � � @@�4J7 \� �' 1 f• t f 744,4 -G "•. r ' V go B'�B�R o •,•.i� --. r-5�v �l / � .trAl �4J0 - ._ Yie a�° ','•/ / a / '� ��• Inc a➢�o � --�i`/c�Y �i � �n `•/ � / Lam• � ti\ au - $ $$8 m ll 9a Q\ x gig L 0 7 Z .471 474 470 \\ \ -473 is (3a `� an2�'°..S N 4 • t7 m z m ��3 zam m oq o a a o n z '° $ o 9 a � � 1A � -L' � � G e L S •.3 � � & H € S S .°3 � m a n 0 °°y n n O Zis ZZa vm, m � S 9 $a no �O 112 _o r PRELOAD Prestressed Concrete Tanks Mr.John Hamm, PE ' May 3,2018 Stantec 1905 Aldrich Street,Suite 300 Austin,TX 78723 Project: Village Creek Water Reclamation Facility 5MG Liquid Biosolids Storage Tank Fort Worth,TX Re: Removal of Slurry Wall Dear Mr. Hamm, Preload has reviewed the effects of eliminating the slurry wall between the tank and the pond. Uplift or flotation of the tank due to seepage of the pond water is not a concern. The overtopping elevation of the pond is 474.00',and the elevation of the tank floor ranges from 474.25'to 475.00'. Therefore,even if the pond is overflowing,there would be no net uplift pressure on the tank floor. If you have any questions,or require additional information, please contact this office. � U Brett H. Henning, P.E.,S.E. Lead Structural Engineer PRELOAD 502.974.6623 Mobile (Primary) 1631.231.8100 Preload 4000 Tower Road• Louisville, Kentucky 40219 . 125 Kennedy Drive,Suite 500• Hauppauge, New York 11788 631-231-8100• Fax 631-231-8881 •www.preload.com Subject: UPLI Pr By:(3tf)q Sheet#: PRELOAD ���� ���� /� 11 Date:-5 n www.PRELOAD.com Project: ���'r l/�' � T-X Job#: 19 PU16 q 1 L �,S�LL)AAV ,4LL - &T UPc.1�`� G�CcI h 6L 1475 o' EL 41Ti -Z J ----------------- 9L 417q.CID EL y 3.9Z 1 y,c>�'- 731 Z — .6 �„ o. 33 156 P�F(a'33 Pslr A'roR- y` 5 �� 5 0 PRELOAD - 4000 Tower Road, Louisville, KY 40219 - (888) 773-5623 peoleet Rain Oaat(Rorembe(2018 thru Alrch 20201 Mojrl t 8ol0id'/C12 P,ciect Y1P nat." 1112D/2011 )Aanlh Rs1n Da f CCI Reln Dep(IWJ Dales lij"O NF-l8 C. tione Cn:cmb rr-IA S 17J(I7,12/76,l2/77,lT/Jdlmud1,17J31 larur-• h) A 01/102,01/b3,01/N(mudl,01/1I Fct••a., 19 F 02ro7,02NBIcoIJ/mudxl2/11,02JI21mWIA2114.02/2Qmuil) Vh'rh.19 Ol,bl 1COM),031DS((dal.03/13,03/I4(m Al Ap-a 19 / Nroslmual,NJl I,01J18,N/19(mudl,N/2l,OJ/11,O3J25(mlxl) �.•79 9 OSJ'01,05/02.05103(rrW),O5J0(I,OSN31mud).45/21.05/22(mud),OS/29,C5/30(mud) I�,ea9 s Oo/IOtmudlC6/171mua),06/77.06/IOIroWLOWNtmuo) Wawa! 7 07110,07/111maa) vll 17 111,/1t,c8,rIS)mua).OSJII.NJ11(mudl.CNu3 Irnba•19 0 rone Or(t,o r.19 9 10110.1 C/11,1OR I,IO/721mud1,10/24.1 O12S(nwa),10/29.1C130,1 Ott]6nud) Ncvrmb:,19 ]Iro7,u/bd(mua).11/72 Nx mbcr-19 S 12J031mDalnt).)2J20,12/Illmud),12/1C{nopx+q.11/20jroDan11 07/091ru palnt1,01/l0,01/131ro PanIL01/It.(na palrltL01J1Slna palnt),OIJ16,01/I7,01/17(ro laruar 10 1S "nQ,Olf21,01/23(noptlnt),01/11(nopt,M).OI/11.01/19(mudl 01/03.0111D1(rrW)•011051cdd no palntl,O)ro6lcold ro DaMl7/f0,OIJI IAI/12,01/i3R^ud),02/1F(no F:b•wry)0 1) p int),02/19,07/20,0)/211mud) 1lrch 20 11 03/OD,03/t75(rru!),03/U,03/i6,03117,03111,03119,07J20)mua},03f13(oud),03130,07/311mud) d ,620 I,io•20 R;••10 A,vvd-20 5«pkrnb••r-)0 Total Rain Days(Work Days)- too Rain Day Allowance CMilnall= •30 alnD Talana.onlrPrrdl 1• 70 Riu SubSJ.m;lal Ccmpld Un l(CA)l- 6110120)0 Cl2 Sa5ltantlal Comal:l on ICOdl)= S/23/Itl10 i. r... .t - 91Y:207C Thanks& Have a Great Day, Ryan Glanz, PE CONSTRUCT04%. inc 2560 Technology Drive,Suite 400 Plano,TX 75074 972,422.0014 office 214-783-8007 cell