draft pool report

8/2/2019 Draft Pool Report

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Prepared By:

Medford High Scl lOOIMedford, MassachusettsPool Facility Study

Draft: Nov. 12,2007

Prepared For:Mr. John Buckley; Director of Management and OperationsMedford Public Schools489 Winthrop Street

Medford, MA 02155

Drummey Rosanc Anderson, Inc.141 Herrick Rd.Colby Hall

Newton Centre, MA 02492

With:Simpson Gumphertz & Hegel'41 Seyon StreetBldg. 1, Suite 500Waltham, MA 02453

City Seal; City of Medford, MA

And:Mr. Philip A. PorterPool Design Consultant

69 Eunice CircleWakefield, MA 01880


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Drummey Rosa ne Ande rson, hIC.Architects11112/2007

Med fo rd H ig h S ch oo l P oo l S tu dy R epo rt

Table of C ontents

JC---~C - 1. Cover Letter\ w ith Acknow ledgements~. 2. Introduction

3. Executive Summary

4. Reporta ) In troduc tionb ) Findingsc) O ption s / C o sts

d) Recommendatione) Summary

5. Appendix A - SGH Reporto n P oo l &Natato rium S tru ctu re an d HVAC

5. Appendix B - Phil Porter Reporton Poo l Equ ipmen t

6. Appendix C - Kalwall Pricing Information


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Mr. Carl F. Franceschi, AlA,Principal Mr. Paul S. Brown, AIA,Project Manager

DRA Letterhead

Draft; Nov. 12,2007Mr. John BuckleyDirector of Management and OperationsMedford Public Schools489 Winthrop StreetMedford, MA 02155

Re: Medford High SchoolPool Facilities Report

Dear M1'.Buckley:We are pleased to present the attached report describing the existing conditions of theswimming pool (and natatorium) at Medford High School.The report is intended to assist the City of Medford in decision-making, with regard tooptions for continued use of the facility. The team of Drummey Rosane Anderson,Architects, along with our consultants Simpson, Gumphertz and Heger, and Mr. PhilPorter, is pleased to have had the opportunity to be of service to the City of Medford onthis important project.We would like to thank you for the guidance you have provided, and to acknowledge thehard work of other important people who have contributed greatly to the success of thisproject. In particular:

Mr. Paul Edwards, Senior Custodian, Medford Public Schools, and Mr. Ted Gently, Construction Project Manager, Ted Gentry AssociatesBoth of these individuals provided valued help in guiding the project team towards thecompletion of the project goals.

Please do 110t hesitate to call if you have any questions about the contents of the enclosedreport. We look forward to being of continuing service to the City of Medford on thisproject, and on other projects in the future.

Very Truly Yours,DRUMMEY ROSANNE ANDERSON

., .t


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The rep~rt i.S.ntende? to....ssist the ~ity ~~~~~dfo.-r~i~d~~;~-making, wi~hregard tooPtlO:: foreon~~llcduscOflh"\"r'\~i'/'bH-eIlI~ atMedford High School.Th pool f i i : c ' l i is an im eort nt art of he hi~ scho 1,knd is a facility which also

study's i .tel de t~.answer quqstions re~~r~in the exter t_9Jrepairs needed, the timeframe in hi. h t lOS JP i ar needed; nd V ~ _ C sts involved. A full range of optionsvas co ~iJelfd~~}JJrar:l;-cloSing the facility, to construction of anew) \__. replacement facility.-._..~ .. .~

Medford High School Pool Study Report

(Introduction

The team of Drummey Rosane Anderson, Architects, along with our consultantsSimpson, Gumphertz and Heger, and Mr. Phil Porter, is pleased to have had theopportunity to be of service to the City of Medford on this important proj ect, and wehope that the information contained herein is useful for your needs.

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Drummey Rosane Anderson, Inc.Architects 11112/2007


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Drummey Rosalie Anderson, Inc., Architects Page 1 of1.-

Medford High School- Pool Study ProjectExecutive Summary DRAFT11112/07

Findings:The structural exterior frame of the building appears to be in acceptable condition,including the vertical structural steel, vertical concrete walls, steel roof framing, and roofdeck.The translucent fiberglass panels (Kalwall brand), which surround the pool building atthe upper half of the exterior wall, are in very poor condition, and need to be replaced atthis time.(The roof is in good condition.The pool concrete structure, the actual body of the swimming pool itself, is in faircondition with areas of localized defects at window ports and drains. However,the pooldeck, the walking surface and structure below, is in very deteriorated condition. Thedeck requires immediate shoring for safety reasons, followed by comprehensive repairsin the near term.The HVAG (interior air conditioning) system is out-dated and apparently not operatingproperly, and needs to be replaced with an up-to-date humidity-control system.Much of the pool operating equipment, including filter equipment and the pool waterheating system, is at the end of its useful life and needs replacement in the near term.Note that the locker areas were not investigated, and issues such as accessibility fordisabled persons were not considered for this study, which focused on infrastructure ofthe pool and the natatorium enclosure. The City of Medford needs to be aware thataccessibil ity requirements may be triggered upon expenditure of funds for repairs to thepool building.


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Drummey Rosalie Anderson, InG.,Architects Page 2 of2

Medford High School - Pool Study ProjectExecutive Summary

DRAFT 11112/07

Options:Four options for the future were considered, including:\ ~

'Mothballing' the building and Sh\utti,g d~npps~tians: with the expectation offuture funding for future-repairs. rfMinimal re~rS~~'8in~ 6~r ti~~s, fo owed 'y a .ro . ram of additional work. Comprehensive re va~. \) RePlace.mtnfWit~h ew fad ity.The costs and ben~fit of ea \0~1i se R f ns are discussed in more detail in the bodyof the report, U

Recommendation:The recommendation of the study team is to proceed according to the second listedoption: minimal needed repairs in the near term (to allow pool use to continueuninterrupted), followed by more comprehensive repairs at later dates, according to asuggested schedule, See additional detailed information in the body of the report,Following this recommended plan, suggested budgets for repairs are as follows:Year 1: $450,000 Shore Pool Deck (and piping); perform maintenancerepairs upon, and/or replace, critical equipment.Replace "Kalwall" daylight glazing panels,Structural Repairs; replace additional equipmentReplace HVAC system and controls.Renovate interior and wall finishes.Year 2 ~10:Year 3 ~10:Year 4 ~10:

$950,000$350,000$625,000Note that, following the immediate critical repairs, our timeline summary suggests thatthe remaining work could be delayed for as much as 10 years. However, delaying thework is not recommended. It is likely (particularly concerning operating equipment) thatdelaying further work will result in increased maintenance and operating expenses. Seeincluded tables for additional information.

Summary:The existing facility is in generally poor condition at this time. Repairs are needed,including immediate work to prevent structural failure of the pool deck, in order to protectlife-safety and maintain operations.Because closing the facility would eliminate desirable community and school programs,and would incur some expenses, the Design Team believes that a program ofscheduled, systematic repairs over a period of 5 years, should provide the City ofMedford with the best overall outcome regarding this facility, at a reasonable cost andwith minimal disruptions to operations. The City should budget a minimum total value of$2,375,000 for this work,(This value is presented in Fiscal Year 2007 dollars; inf lationary adjustments should be added to thisamount, depending upon the implementation schedule which is ult imately selected).


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Medford High School ~ Pool Study ProjectReport

DRAFT 11112/07

Introduction r--\The purpose of this study was to provid I ' i E \ Cit~}Ord\Wi(~a recommendation,supported ?y a?curate and ..?'refally res. arc.Hf(d\~~t:~lon, ~~~grding fU,tu~~use of theeXlstmg sWlmmlnfLPooH~cll~ty ~Uy1es fo r ~~~ SO~OI _Speci ca~, to prioritizesu gg ested re pair~ nd o ulrn ~ aW rhe t bl f1~~cl \o . t tt . t will sa eJ maximize utility of thepool for the longe t Pf'\d 'f~ime at n ppropri8_) ex ense vaiU1 .This study was foe . e~~} t e\ h~ al ~r environment of the pool andnatatorium enclosur{~ ~nadi ~ciln~e an examination of adjacent facilities such asthe locker rooms, Sh1:~ etc. . The underside of the structural deck below the lockersand showers was examined, and was included in this report. It should be understoodthat expenditure of funds on repairs and renovation of any part of the High Schoolbuilding, beyond certain regulated values, triggers the need for comprehensiveelimination of any barriers to access for disabled persons. The value of the worksuggested in this report, would probably trigger such compliance in areas such as thelockers and showers, and possibly throughout other areas of the school building. Theevaluation of the scope of those potential barrier removals, in the pool building and inother areas of the entire facility, was beyond the scope of this study, and is not includedin the findings, options, or recommendations herein.S tu dy T ea m : The study was prepared by Drummey Rosane Anderson Inc" Architects,with additional technical support from:Simpson Gumpertz & Hegar, (SHG) Structural and Mechanical Engineers,Mr. Philip A Porter, Pool Operations Consultantand the Kalwa" Corporation, Mr. Charles Shriner, Sales Representative.DRA made visits to the site on the following dates: August 21, 2007, with the entire project team, for general observations andphotographs, September 18, 2007, to accompany SGH,

and October 25, 2007, with Kalwall Corporation.The consultants made additional visits to the facility, on dates as stated in their attachedreports.


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Medford High School- Pool Study ProjectReport

DRAFT i/12/07

Findings GExisting Conditions, Building Structure a -a;~vJ~~~~_ \_~The structural ex~or--ff,m of{th~ b .ild n~p. e~~; to_b~ in a~~table condition,including the vert ical structu I ~I, eic~Jo ~r te~alls, st el oaf framing, and roofdeck. There is so e ~~~c of moi tur mJgratr~n ina andth . gh the verticalconcrete structural ex eri r ~ IIs,\9\1d a IIeJo~~~ '-8 eas of defective conditions inthese sam.ewalls, ( s se t i le~d\tnt~e\botiV>f the report), but the basic structural shell ofthe building appears to h ve a ~on'a6fe service life remaining, with some minimalrepairs needed. Rep irs 0..{ e exterior concrete walls should be made at the same timeas the more comprehensive repairs to the concrete pool and pool deck.The roof has been recently replaced, and shows no obvious signs of active leaking.With proper maintenance, the roof should have a normal service life remaining,The translucent fiberglass panels (Kalwall brand), which surround the pool building atthe upper half of the exterior wall, are in very poor condition, and need to be replaced atthis time.

(There is evidence of moisture migration through the ceramic tile facing on the interiorside of the exterior concrete walls of the pool building. The source of this moisture isthought to be a combination of infiltration from the exterior, through the porous concrete,as well as internal humidity, which is cyclically being drawn into the exterior wall, andthen drawn back into the interior of the building under varying interior environmentalconditions. Minimal spot area repairs of the interior tile are needed, but are not critical atthis time. Improved mechanical control of the interior humidity levels may help toalleviate this condition.Existing Conditions, Pool Structure and Pool Deck:The pool concrete structure, the actual body of the swimming pool itself, is in faircondition with areas of localized defects at window ports and drains. Localized repairsare needed at these areas. The glazed ceramic lining of the pool is in poor condition,and should be comprehensively repaired with new grout and replacement tile as needed.The pool deck is in very poor condition. It needs immediate temporary shoring, followedby comprehensive structural repairs in the near term.Existing Condltlons, HVAC System:The existing HVAC system, by today's standards, is poorly designed for a pool'environment, and does not appear to be operating properly. Some of the existingequipment may be able to be re-used, but additional equipment to control humidity levelsis advised, along with extensive re-working of the controls system, to ensure properautomatic operation with a minimal reliance on human control on a daily basis.


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Medfo rd H ig h School- Poo l S tu dy P ro jec tReport

DRAFT 1 1 1 1 2 1 0 7

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Drummey Rosane Anderson, lnc., Architects Page 4 of}VlO

Medford High School- Pool Study ProjectReport DRAFT 11112/07

( Options I CostsOptions that the City might want to consider ran~e-ff()fl;\',omplet replacement of thepool 'building', to terminationof use of t eilitl) a~rJrfio 1 l ~ ~ \ { 't for future repairs.Actual demolition of the fae~.1~Q\t on~ eresss-~"'} opti CrhiS study.Option1: Shut~;:nn~p tlons~(and moth-~~i th b i~n~\~re ~r) . .With appropriate C?~Si rati n ?!Jhe benefits that the facility provides to the HighSchool students and taff nd to the community at large, the City of Medford may wishto consider the option of terminating operations, reducing operational expenses, andeliminating the need for expensive repairs and renovations. If use trends indicate adeclining interest in swimming sports and recreation, this may be a serious option toconsider. This option assumes that use trends might change again in the future, and theprovisions should be made to stabilize the building rather.than demolish it, so that itcould re-open again at some point in the future.Safely shutting down and 'mothballing' the building and equipment is not without costs,however. Items of work that would be required in order to properly implement a shutdown, while stil l allowing for the possibility of future re-use, include:

Item BudgetDrain pool, make safe with fill or coveror barrier. $20,000 ~$40,000Intrusion alarm system plus doorrepairs. $20,000 ~$40,000Minfmal HVAC repairs for minimalventilation and heat. $30,000 - $60,000Disconnect existing pool operationequipment $10,000 - $20,000Minimal safety netting to catch futurespalls below deck, allowing use ofunderneath spaces. $20,000 - $40,000Annual minimal lights and heat; 5k peryear, 5 years. $25,000 - $50,000Repairs to Kalwall Glazing (prevent pestinfiltrations); allowance $25,000 - $50,000Soft costs: engineering, generalconditions, permits and fees, andcontingency at 2!5% of sub-total. $37,500 - $75,000Budget $187,500 - $375,000

If the City and School department feel that the benefit of current programs in the pool donot support the values of repairs, then closing the facility may be a viable option.However, it should be understood that closing the pool facility is not without costs thatneed to be budgeted.


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Medford High School- Pool Study ProjectReport DRAFT 11/12/07

Option 2:Minimal Repairs to Maintain Operations(fo llowed b y a s chedu led p rog ram of add. {t k na l C ( 0 l .The objectiveof this optionis-te-pro ide he ,,\ax~u. ld\1g-~ m utility of the pool, at theminimal appropriat cap'tal xp nse. T a, 0 pllsh t iSlobje ti ,we have outlined avarious parts of th bIr'1 in . ystem "a d equip pt.. The foil wing is. full descriptionof this advised cou se of ct 0 ,~I~SS' ci tedbeUn and budget costs.The following tables U 8y Z ~ recommended work, associated tlmellne, andbudget costs. This i fO_!D1atlons intended to serve as a tool for decision-making by theCity of Medford and tfie Medford Public Schools. Modifications to this information inresponse to meaningful changes in objectives or other factors over time are bothpossible and encouraged. If meaningful reasons to alter the proposed course of actionbecome evident, then this plan should be updated accordingly. These tables representone possible course of action, based upon our understanding of the needs andconditions at this time.

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Table #1: Immediate Action Items (critical) - First YearItem Description Suggested Crew I Materials BudgetNumber time frame or other basis1-1. Remove loose spa lis Immediate 2 men, 1 week, $7,500plus materialsand disQ_osal.1-2. Temporarily shore Immediate 4 men; 2 weeks, $15,000underside of pool deck, plus materials,and brace deck-hungequipment supports1-3. Repair HVAC controls, Immediate 2 HVAC $7,500test, re-train, reset technicians; 1operations protocols. week, plusmaterials andexpenses.1-4. Misc. HVAC repairs as Immediate Suggested $15,000discovered during step 3. Allowance forunknown findings1-5. Replace existing Immediate Per Kalwall $250,000"Kalwall" glazing system quotation, plusother project

costs,1-6. Repair pool deck surface Immediate 2 men; 1 week $7,500drains. plus materials1-7. Replace corroded Immediate Per Phil Porter $5,000coupling at perimeter report, plussystem supply converter contingency and ..in filter room. project costs1-8. Replace steam heat Immediate Per alternate #2 $50,000exchanger and controls. bid with Boiler


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Medford High School- Pool Study ProjectReportDRAFT 11112/07

contract, plus;~~~~e\t

SUb-total; items above. Immedia~ S1!b-tQtal__..-' $357,5001-10. Desi,gn fees, and r' ~ \ d-25%0 o\,\-total $89,375

contingency value.ter.">, I \himmediate-action \jte'1ls" \\ I,--J1-11, Total; immediatE;! ep~.s I ) 1ml1el,~t~ \ \Total; ro_1!_nd~d $450,000

Item Description \/ ) \_-) 'Suggested Crew / Materials BudgetNumber \ _ >" time frame or other basis2-1. Remove temporary Year 2 -10 2 men, 1 week,shoring, plus materialsand disposal.

$7,500

2-2,

2-3,

2-4.

2-9. Total; Mid-Term repairs Year 2 - 10

Localized structuralrepairs to pool walls.(*See note below table)Structural repairs to pooldeck, including replacingceramic tile walkingsurface.Structural repairs toexterior walls, localizedrepairs.Install new pool filterequipment

Re-grouting entireceramic tile liner of pool.(*see note below table)Sub-total; items above.DeSign fees, andcontingency value forimmediate action items

Year 2-10

Year 2 -10

Year2-10

Year 2 - 4

Year 2 - 5

As notedabove

Allowance, $100 $400,000per s.f, deckarea. 100 x 4000

25% of sub-total $186,875

Total; rounded $950,000

Allowance, $20per S.F. of poolwall surface area,20 x 2000

Allowance

Value fromconsultant report,plus contingency.and project costs.Value fromconsultant report,plus contingencyand project costsSub-total

$40,000

$100,000

$120,000

$80,000

$747,500

N ote: Items 2.2 and 2.6: Repairs to pool w alls are less critical, and c ould b e delayed tothe late mid-term category of repairs, However, it would be much more efficient to dothis structural concrete work at the same time as the substantial deck repairs, and so wehave included these values in this mid-term table,

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Medford High School ~ Pool Study ProjectReport

l)~ 11/12/07

Table #3; Late Mid-Term Budgettem DescriptionNumber $200,000-1.

3-2. $50,000

3-3. $4 per s.f. of roof $40,000area. 4 x 10,0003-4. SUb-total $290,0003-5. 25% of sub-total $72,5003-6. Year 3 -10 $350,000Table #4 - Long Term Repairs (Code compliance, service longevity and cosmetics);Year4 .Item Description Suggested Crew I Materials BudgetNumber time frame or other basis4-1. Refinish interior walls; Year 4 -10 Allowance $40 $200,000paint and tile, including per s.f. wall areaany added waterproofing exterior walls.measures, 40 x 50004-2. Compliance with Year 1 -10 Allowance, value $200,000

Regulations for access unknown at thisfor disabled persons. time.(See note below table) .4-3. Upgrade pool sport Year4-10 Allowance; value $100,000equipment, such as unknown at thisdiving boards, lane time .. . ropes, starting blocks,etc.4-4. Sub-total SUb-total $500,0004-5. Design fees, and 25% of sub-total $125,000contingency value forimmediate action items4-6. Total; Long-term repairs Years 1 - 10 Total $625,000Note: Costs of compliance with access regulations, depends wholly upon the decisionsmade by the City of Medford, with regard to the scope of work over time. Therefore, thisvalue is not predictable at this time, and could vary widely. It is possible that the value ofthe work of this proposed pool rehab project, if done in the short term, could trigger theneed for full compliance with access regulations, throughout the entire school facility. Itis possible that this could be a Significant amount of work, on the order of multiplemillions of dollars of value. As a case-history example, (and a matter of public record) aneighboring town has recently undergone a series of renovation project at their public

Drummey Rosalie Anderson, Inc., Architects Page 7 of71O


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Medford High School- Pool Study ProjectReportHiqh School of similar size as Medford High School. These discrete projects, becauseof their dollar value, triggered full compliance with access regul ions throughout theschool, at an approximate estimated cost of $7million.

DRAFT 11112/07

Summary, Option #2:

technical analysi done b t e \:~ ul in p~ne soRA Th, se reports are attached,and should be co su!rted in 'Per to~~ain more d q n pi te unde 'Standing of the work thatis being proposed t is pion 2 \.__)The total suggeste~"u . I t fo~p~ se two option, is calculated in the table below, bysumming the totals o~41ndividual tables: .Table #1 Immediate Repairs $450,000 .Table #2 Early MidwTerm Repairs $950,000Table #3 Late Mid-Term lHVAC) Repairs $350,000Table #4 Lonq-term Repairs $625,000Total Budget Option #2 Total $2,375,000Note that these budge values include no sophisticated financial accounting for the valueof money over time. Financial budget specialists should account for such time-basedvaluations in response to the anticipated time frame, which (as suggested) could varywidely from 2 years to as long as 10 years. Essentially, the values above are presentedas 2007 dollars, and should have an inflationary adjustment applied by others,

(Option 3: Comp re he ns ive R en ova tion in th e N ea r T ermThis option essentially repeats the scope of work of Option #2, but accelerates the timeframe to complete the work in one comprehensive renovation project. This optionresults in a lower overall expenditure, due to the efficiencies of completing the workwithout repeat contractor mobilizations and the associated soft costs. However, itrequires a much larger cash outlay in the short term, than option #2.At this early stage of the planning process, it would be invalid to attempt to make adetailed analysis of the specific line-item savings that would be realized by acceleratingthe work. However, based upon our experience, it seems reasonable to assume that ageneral efficiency savings on the order of 10% of the total project value, could berealized by doing all of the proposed work as one single project. Thus, for this Option#3, we suggest a budget on the order of $2.1 million, Again, this value is subject to amore complete understanding of the value of money over time; we are presenting thisvalue as 2007 dollars, in order to support a decision-making comparison with the valuespresented in Option #2, Further specialized financial analysis may be needed.Option 4: Rep la cemen t w ith a New Facf lityAt current construction rates, replacement of the entire building would be expected tocost approximately $4 Mill ion dollars. This value was calculated based upon thefollowing assumptions and using the following methodology:


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Medford High School- Pool Study ProjectReport Assumed replacement buHding area at 10,000 S.F .. Existing locker area withbleachers above, to remain. Layout of replacement buil i g to be very similar toexisting building. Assumed area of locker/bleacher rehab ~t-5:o@ .F Square-foot construction cost va~~re ~~pon R. . Means data, from the

publication "2005 S lIareTb t C, S ~ ; A : ] ; t h J,~\Edit on. Specifically,~f~merCiaI..BUildn TYOM. 5 ~ f T I m ~)()dl' En 10 ed', on pages 212 and calculatio~s c f s ) ~ ~lIo: .o Pool ar a \10, '0 U~a eraQe\c9 $200 per S.F.; = = $2,000,000

o LOCk~~~o~ r f 5~0' 0 s. .,.-tehab allowance at $100 per S.F.; =$50~:~OV x .>o Allowa(!.Ce-f r lower level mechanical spaces; 5,000 s.f, at $50 per S.F.;= $250,000.o Inflation at 8%, to convert 2005 R.S. Means values of $2,750,000 dollarsinto 2007 dollars; add: $220,000.o Location adjustment, using RS. Means standards for construction in the

Boston Area, add 15% to buHding costs: 2,970,000 x .15; add $445,000.o Allowance for compliance with access regulations, triggered by thisproject, in other areas of thebuildinq, Same allowance as used in options#2 and #3, in order to provide equivalent decision-making value. (Actualcost of this item is unknown at this time.) $200,000.o Allowance for site costs outside of the footprint of the replacement poolbuilding; (repair paving, re-grade, etc.) $20 per s.f. x 15,000 s.f.:$300,000.o Allowance for demolition of exlstlnq structure, and temporary controls,relocation of loading operations from adjacent loading dock, etc.;$400,000.o Contingency and soft costs, at 25% of above values ($4,315,000 x .25);$1,078,750.o Total rounded to $5,400,000.00

DRAFT 11112/07

Recommendat ionBased upon our understanding of the desire to continue the operation of the pool facilitywithout compromising safety or program utility, and based upon our subjective .understanding of the financial capacity of the City of Medford to support the costs ofrepairs, it is our recommendation that Option #2 is the preferred course of action. Thisoption provides for:

Uninterrupted operation of the pool facility and programs for the near term. Protection against safety issues related to the potential failure of the pool deck. Minimal expense in the near term. Reasonable value for future expenses, with regard to the benefits of continuedlong-term serviceability. Minimal disruption of program activities, with adequate time to prepare for thisnecessary disruption, for the large portion of the work in about 3 years. Long-term use of the facility, with proper maintenance. Lower costs when compared with pool facility replacement.


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Medford High School- Pool Study ProjectReportDRAFT 11112/07

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Opt io n #2: M in ima l repa irs to ma in ta in o pera tio n s , fo llo w ed by a pro gram o fa d dit io n a l w o r k,The co st o f th is o ptio n w as es tim ated, fo r dec is io n-m akin g purpo ses , a tapp ro x ima t ely $2 ,375, 000 . Op tio n #3: Co mprehen sive ren ova tio ns .The co st o f th is o ptio n w as es tim ated, fo r dec ls lo n-m akln q purpo ses , a tapp r o x ima t e ly $2 ,1 00 ,0 00 . Opt io n #4: Repla cem en t w ith a n ew fa cility .The co st o f th is o pt io n w as es tim ated, fo r dec is io n-m akin g purpo ses , a tapp r o x ima t e ly $5, 400 ,0 00 ,

O ur reco mm en da tio n is to pro ceed a cco rdin g to O pt io n #2. W e fee l tha t th is a ppro ach,ba sed upo n o ur s ub jec t ive un de rs ta ndin g o f the n eeds , go als , a nd res ources o f the C ityo f M edfo rd, pro vide s the-bes t va lue fo r the co mm un ity ..Tha nk yo u fo r the o ppo rtun ity to be o f s erv ice to the C ity o f M edfo rd, M as sa chus et ts .Our en tire tea m ha s en jo yed the cha llen ge o f th is p ro jec t , a nd w e lo ok fo rw ard tores po ndin g to a ny fur the r ques tio ns o r co mm en ts w ith rega rd to the in fo rm at io np re se nte d in th is re po rt ,


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Drummey Rosane Anderson, Inc.Architects

11112/2007

Medford High School Pool Study Report

SGH R eport - Appendix A


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12 November 2007 S IM P S O N G U M P E R T Z & H E G E R( I Engineering of Structuresand Building Enclosures

Mr. Paul S. BrownDRA Architects141 Herrick RoadColby HallNewton Centre, MA 02459~2218Project 070800 - Evaluation of Existing Concrete Swimrnlnq-Pool Structure and HVACSystem, Medford High School, Medford, MADear Mr. Brown:At your request, Simpson Gumpertz & Heger Inc. (SGH) evaluated the present condition of theconcrete deck and concrete pool walls at the Medford High School (MHS) swimming poollocated in Medford, MA. In addition, we evaluated the present condition and operation of theHVAC equipment in the natatorium. This preliminary report summarizes our findings andconclusions.1. INTROOUCTIONThe MHS pool was constructed around 1970 and was renovated about 15 years ago byregrouting the deck tile. The pool itself measures approximately 77 ft by 62 ft and is surroundedby a tiled deck on all sides (Photo 1.)

( The deck comprises a 1 in. square tile set in a 1"3/4"in. setting bed atop a 6 in. structuralconcrete slab. The structural concrete slab is supported by walls on the north, east, and southsides and by 14 in by 14 in concrete columns on the west side. The deck slab on the west sideof the pool is continuous beyond the CMU walls that define the west side of the natatorium,The bottom slab of the pool appears to be founded directly on the underlying soil and isinaccessible, but there are accessible spaces below the deck and around the sides of the pool.There is a mechanical room abutting the south pool wall (Photo 2), a pipe gallery around theeast and north walls of the pool (Photo 3), and a storage room abutting the west pool wall(Photo 4.). The height of the pipe galleries is 6 ft - 8 in., and the height of the mechanical roomand the storage room is 12 ft . It appears that the floors of the mechanical and storage roomsare supported on grade; it is unclear whether the pipe gallery floors are supported on backfilledsoli or are elevated. Pipes running through all four rooms are supported from embeddedfasteners in the underside of the deck slab.

We understand that MHS wishes to take a proactive approach to their facilities maintenance,and MHS is assessing the repair of the swimming pool is part of their planning. Therefore, theobjective of our work is to evaluate the existing condition of the swimming-pool structure and toprovide conceptual strategies for remediation.

SIMPSON GUMPERTZ & HEGER INC,41 S eyo n S treet. B uildin g 1, S uite S OOWa lth am , M as sa chu se tts 0 24 53rno'o: 781.907.9000 fox: 781.907.9009www.sgh.com

BostonLosAngelesNew yo,kSon FranciscoWoshington, DC
http://www.sgh.com/http://www.sgh.com/


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Mr. Paul S. Brown - Project 070800 - 2- 12 November 2007

( 2 . SCOPEOFWORKTo date, our work on the project includes the following: Measure the dimensions of the pool deck and all adjacent rooms beneath the pool

deck to create a working set of drawings. Conduct a condition survey of the accessible areas of the topside of the pool deck, theunderside of the pool deck (storage room, pipe galleries and mechanical room), thepool walls, and other interior/exterior walls. This survey includes visual observations, adelamination survey (sounding with chain, hammer, and delamination probe), anddocumentation of the approximate location and extent of surface deterioration. Collect a total of five existing concrete spalls from the underside of the pool deck. Extract a total of four core samples from representative areas of the topside of the pooldeck and from the pool wall. Make half-cell corrosion measurements and associated corrosion-rate measurementsat representative areas on the underside of the pool deck, pool walls, and otherinterior/ exterior walls. Perform nondestructive impact-echo testing at representatlve areas of the structure. Perform limited petrographic examinations on two core samples to observe the generalcondition of the concrete and to determine if there are on-going deleterious reactions inthe concrete.( Test all the core samples and three of the collected spall samples for chloride contentand the depth of carbonation. Conduct non-destructive ultrasonic testing on two filter tanks in the mechanical room toestimate the remaining filter tank thickness. Assess the condition, operation, and performance of the HVAC system in the poolspaces. Prepare this report.3. FIELD INVESTIGATION3.1 Visual Inspection and DelaminationSurveyOn 17 through 19 September, 2007, Uying Jiang, Timothy Montgomery, and Matthew Shermanof SGH visited the site to perform our work. We performed a visual survey and a delaminationsurvey of the topside of the pool deck, the underside of the pool deck, and the pool walls andthe other walls. We made the delamination survey on the topside of the deck by draggingchains across the concrete to listen for indications of delamination .. In all of the rooms beneaththe pool deck, we performed an underside delamination survey using hammers anddelamination-sounding devices to sound the underside of the slab and walls. The survey map


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Mr. Paul 8. Brown - Project 070800 - 3 - 12 November 2007

( that we generated for the underside of the pool deck is shown on Drawing 8-1. Our survey mapfor the topside of the pool deck is shown on Drawing 8-2. We could only sound limited areas ofthe underside of the deck in the storage room and mechanical room because HVAC ducts,tanks, and pipes obstructed our access. Our detailed observations of each area are listedbelow. During our survey, we also photographed examples of the damage in both the topsideand underside of the pool deck, and the locations of the photographs are presented in thisreport are indicated on Drawing 8-1 and 8-2.3.1.1 North Pipe GalleryWe made a detailed survey map for the north pipe gallery to serve as a representativedescription of the types of deterioration that we found on the underside of the pool deck(Figure 1). As shown in our map, we noted significant areas of delamination, spalJed concrete,and actively leaking cracks on the underside of the deck and significant areas of delaminationon the north wall, especially at the east and west ends of the gallery. We estimate that theunderside damage (spalled and delaminated area) covers approximately 35% of the entireunderside area. The following is a summary of our findings in the north pipe gallery: The delaminations at the underside of the deck consist of a thin (1-2 in.) layer ofconcrete that has broken away from the surrounding concrete. Typically thesedelaminations revealed corroded reinforcing steel, some of which had complete loss ofsection (severed) while others had only minimal section loss (Photo 5). Thedelaminated areas on the underside of the deck vary in size from 1 sq ft to 8 sq ft. We noted approximately ten cracks in the underside of the deck accompanied by whiteefflorescence deposits (Photo 6). These cracks are oriented perpendicular to the poolwall and are well distributed along the entire underside of the deck in the north pipegallery. A few of these cracks were actively leaking at the time of our survey.

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We noted heavy efflorescence along the top half of 2/3 of the entire north wall of thegallery, as represented by green dots in Figure 1. The water causing this efflorescenceappeared to be leaking from the joint between the top of the wall and the bottom of thepool deck (Photo 7). We noted four vertical cracks in the pool wall with efflorescence localized in the vicinityof the crack (Photo 8). We noted a large (full height of the wall by approximately 8 ft long), deep spall at thewest end of the north wall that exhibits heavy efflorescence. The vertical reinforcingbars are completely debonded from the concrete at several locations within the spall(Photo 9). There is a full-height delamination at the northeast corner of the pool wall (Photo 10) We also noted that the concrete beam at the east end of the north pipe gallery iscracked on the bottom and on both side faces, and the concrete is beginning todelaminate.


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Mr, Paul 8, Brown - Project 070800 -4- 12 November 2007

( 3.1.2 East Pipe Gallery

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We observed significant areas of delamination, concrete spalls with exposed corroded rebar,and several transverse (perpendicular to the east pool wall) cracks with built-up "stalactites" ofefflorescence (such as in Photo 6) on the underside of the deck in this area. The size ofconcrete spalls ranges from 1sf to over 6 sf. The pattern of the damage on the underside of thedeck in the east pipe gallery is similar to that of the north pipe gallery, but the deterioration ismore severe. Due to the large area of damaged/delaminated concrete. we did not recordindividual damage areas. and instead divided the entire area into five sections (labeled EP 1 toEP 5) and we estimated the percentage of damaged area over the entire area for each section.Figure 1. for example, represents an estimated 35% damage, including cracks, concrete spallsand delaminated areas, over the entire underside area for north pipe gallery. The survey resultsand estimated damage percentage for each section are shown in Drawing 8-1.We also noted that the pool waH and the east wall in the east pipe gallery is generally in goodcondition, with only a few localized cracks with efflorescence. We did note a 4 ft wide, full-height, hollow-sounding, delamination area on the east wall as indicated on Drawing 8-1.The drain pipe from the deck above at the northeast corner was actively leaking at the time ofour survey.3.1.3 Mechanical RoomWe visually observed the walls and ceiling of the entire mechanical room and sounded theaccessible areas of the underside of the deck using a delamination sounding device. As in thenorth and east pipe galleries. there are large delaminated areas and concrete spal ls withexposed corroded rebar. However, there is a large area of sound concrete in the middle of themechanical room near the outside wall under the office located on the topside of the deck. Dueto the large area of damaged/delaminated concrete. we divided the entire area into eightsections (M1 to M8), and we estimated the percentage of damaged area over the entire area foreach section. The survey results and estimated damaged percentage for each section areshown in Drawing 8-1.The visible cracks ran both perpendicular and parallel to the south pool wall. and most of thecracks have "stalactites" of efflorescence, We also observed a localized area (approximately 20sf) of map-pattern cracking (an interconnected area of fine cracks creating many small "blocks"on the surface) in the southeast corner just above the heat exchangers. We noted several activeleaks during our survey that were dry during our preliminary inspection on 21 August 2007.3.1.4 Storage RoomWe visually observed the entire storage room and sounded the accessible areas of theunderside of the deck using a delamination sounding device, The damage pattern on theunderside of the deck in the storage room is similar to that observed in the other surveyedareas, including large delaminated areas. concrete spalls with exposed corroded rebar, andlongitudinal and transverse cracks for most of the underside areas in the storage room, exceptArea 82. As in the other areas, we divided the underside of the deck in the storage room intoseven areas and estimated the percentage of damaged area over the entire area for eachsection. The results of our survey are shown in Drawing 8-1. In Area 82, the damage is limited( to paint peeling and two cracks with visible efflorescence.


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Mr. Paul 8. Brown - Project 070800 12 November 2007

There are multiple embedded channels in the storage room ceiling spaced at approximately 8 fton center, which support the pipe hangers for the three (12 in. , 6 in., and 16 in.) pipes runningthrough the space. There are also mechanical fasteners in the ceiling supporting the adjoiningductwork. Many of these channels and anchors are severely corroded, and some are .Iocated inor near areas of spalled or delaminated concrete (Photo 11).Upon our arrival on the morning of our last day of surveying (and as a swim team practice wasjust ending), we observed heavy active leakage from a ceiling crack between the entrance doorto the storage room and the door to the mechanical room. The water continued to leak throughthe slab for almost an hour after we arrived and created a large area of ponded water on thestorage room floor.3.1.5 Pool Deck AreaWe visually surveyed the topside of the pool deck and observed ponding water, cracking in thedeck, and surface staining. We found approximately twenty-one cracks on the surface of thedeck. The cracks ranged in length from 2 ft to 16 ft long. These cracks are typically located ator adjacent to floor drains (Photo 12), or at the corners of the pool. We noted one location in thenortheast corner of the pool deck where a higher density of cracking and ponding is present(Photo 13).We conducted a delamination survey over the entire topside of the pool deck by dragging achain over the surface and noting areas that sounded hollow or high-pitched. We noted anumber of small (1 to 4 sq ft) shallow delamination areas over the deck, and one largedelaminated area of approximately 47 sq ft near the northwest corner of the pool deck (Photo14). The delaminations were typically limited to areas adjacent to the pool edge or to drainpipes. Because of the 2 in. thickness of the thick-set tile and mortar setting bed, this topsidesounding likely only indicates delaminations within these upper layers.We also noted four large areas of ponded water near floor drains and rust staining on the deck(Photo 15), on the legs of the diving board supports, and at the bases of the pool ladders(Photos 16).The results from our topside surveys are shown in Drawing 8-2,3.2 Sample RemovalWe extracted a total of four 3-in.-diameter core samples for chloride testing and petrographicexamination. Three of the four cores are full-depth from the pool deck, and one core is a partial-depth (approximately 3.5 in. long) core from the east pool wall. We did not observe any type ofwaterproofing membrane below the tile or mortar setting bed in any of the deck cores. The corelocations are shown on Drawings 8-1 and 8-2 and are labeled C-1 through C-4. The cores aredescribed in Table 1.


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Mr. Paul S. Brown - Project 070800 12 November 2007

Table 1 - Core InformationCo re co mpo sit io n a ndt hic kn es s es (In .)

Loca t i on & Core Mo r t a rCo r e Rea so n fo r Length T ile s et t in g Co n crete10 Se lec t i on (ln.) bed S tee l Co n dit io n No te sOn s ou th po oldeck abo ve #5 ba r lo ca ted a tm e ch a nic a l r oom . 4 .5 in . fro m to p o f S oun d co ncre te w ith n oC1 S ele ct ed a t a re a 8 - 1 / 4 3 / 8 1 - 3 / 4 6 - 1 / 8 deck; #4 ba r in d ica t io n o f cra ck in g o rw it ho u t u n der s id e lo ca ted a t 5 .5 In . de lamina t i on .de lam in a t io n o r from to p o f deck.s u rf a ce sp a lli ng .On s ou th po old ec k a bo v emecha n ica l ro om #5 ba r lo ca ted a t De lam in a t io n Immedia te ly(be lo w div ing 7 in . from to p o f b elo w t he # 5 b ar; a fu ll- de pt h,C2 bo a rd). S e lec ted 8 3 / 8 1 - 1 / 2 6-1/8 deck; a sma ll w ide cra ck (up to 0 .02 in .)a t a re a w ith s te el s upp ort b ar w it h w hit e d ep os it s a ls ounders ide is a ls o v is ib le . p resen t.d elam in a tio n a n dcrack ing.On eas t po ol deck #4 ba r embedded B ro ke n In t he m o rta r s et tin go ver ea s t p Ipe in the bo t tom o f bed a n d jus t a bo ve the #4ga lle ry (n ex t to the co re (7 In . ba r durin g co r in g;flo o r dra in ). from to p o f deck) de lam ina t io n immedia te lyC3 S e lec ted a t a n 7-314 3 / 8 1 - 3 / 4 5 - 5 / 8 immedia te ly be lo w the #4 b ar (a bo ve th ea re a w it h a bo v e t he c o rr o de d b a r r em n a n ts );u n der s id e su rf a ce rem nan ts o f a c o nc re te c o ve r b elo w #4 ba rde lam in a t io n a nd co rro ded b o t tom ha s c lea rly s pa lied awa y a tspal l lnq. ba r (po ss ib le #5). co re .O n ea st po ol w all. S o un d c on crete w ith n oS e le ct ed b ec a us e No ba rC4 o f n o v is ib le 3 - 1 / 2 - - 3 - 1 / 2 encoun te red In dic at io n o f c ra ck In g o rde te r i o ra t i on . de lamina t i on .

3 . 3 Impact-Echo (IE) TestingWe performed nondestructive impact-echo (IE) tests on the east pool wall in the east pipegallery (IE Area 1) and on the north wall in the north pipe gallery (IE Area 2) in attempts tolocate any areas of deep delamination and to measure the approximate wall thickness. At eacharea, we made three horizontal lines of measurements, with the lines at 2 ft above the center ofthe wall, at the center of the wall, and 2 ft below the center of the wall, respectively. In IE Area1, we made 11 measurements at 2 ft on center along each horizontal l ine, starting 28 ft 7 in fromthe south end of the east pool wall. In IE Area 2, we made 10 measurements at 2 ft on center,starting at 6 ft 10 in. from the west end of the north wall At each test location, we identified theapparent concrete thickness, any deeper-than-expected indication, and any indications ofdelaminations at the level of the far-side reinforcement or any other internal features. We couldnot perform the IE test where there were shallow surface delaminations because shallowdelaminations block the signal from penetrating beyond them; no signal depths are reported forthose locations. We did not conduct any IE tests on the underside of the deck due to the visibledelamination and spalling.


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Mr. Paul 8. Brown - Project 070800 -7- 12 November 2007

The results of our measurements are shown in Figures 2 and 3; unusually-shallow depthsindicate likely delaminations. At the pool wall (IE Area 1), the IE testing was not alwayssuccessful in determining the interface between the fill mortar and the concrete due to thesimilar densities of the material. We noted irregular and deeper-than-expected values at thewall of the north pipe gallery. These are discussed later in this report.3.4 Corrosion Measurements3.4.1 Half-Cell TestingWe evaluated the likelihood for corrosion on the underside of the deck slab at two test locations,the pool wall and the north wall, using the half-cell potential (HC) method as described in ASTMC876. The test rapidly and non-destructively provides an indication of the likelihood of corrosionof the embedded reinforcing steel by measuring the voltage (technically termed the "potential")between the reinforcing steel and a reference half-cell. By the test convention, this voltage isexpressed in mV (as compared to a copper-copper sulfate reference electrode), and thenumbers are typically negative in sign, with more negative values indicating a greater likelihoodof corrosion, Our test locations are shown on Drawing 8-1, labeled HC Areas 1 - 4; the resultsare shown in Figure 4 in the form of equipotential maps, where the contour lines indicate areaswith the same measured potential. Note that HC Areas 5 - 7 are not shown on Drawing 8-1because they are much smaller than HC Areas 1 - 4. It is important to note that the half-cellpotential will produce a false reading (very low negative or positive reading) at areas ofdelamination because the delamination interferes with the electrical continuity of the concrete.

T bl 2 S t R ItH If IIMe - umm,!fY 0 a -ce easuremen esu sArea: He Area 1 HC Area 2 He Area 3 He Area 4 HC Area 5 He Area 6 He Area 7

Underside of Underside ofUnderside of Underside of South pool deck in deck ofLocation East pool wall deck in east deck in north North wall wallin mechanical mechanicalpipe gallery pipe gallery mechanical room; room;

room adjacent to adjacent toCore C1 Core C2.Test 33 44 33 33 10 4 4points

Test Area 80 120 80 80 4 4(sq tt) -Half cell -282 to 0 80 to -50readings -300 to -131 -526 to 236 -380 to -138 -285 to -133 (-329 near (-249 on -411 to -346crack near(mV) crack) Core C1)

No spallingSevere Severe or delam- Near CoreNo visible spalling and Spalling and spalling and Ination C1; one Adjacent toNotes spalling or exposed exposed delam- present; one crack with delam-delaminationrebar

rebarination

full-heightwhite

ination andpresent. present. present. present. crack with staining. spalling.whitestaining.

3.4.2 Corrosion Rate TestingWe made limited corrosion rate tests to calibrate the half-cell testing. The corrosion-rate testingis useful because it supplements the half-cell testing (which only indicates the likelihood ofcorrosion, but not its magnitude) by providing the actual rate of corrosion. We used a


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Mr. Paul S. Brown - Project 070800 -8- 12 November 2007

( commercially-available GalvaPulse unit that determines the corrosion rate by applying a briefelectrical pulse to the reinforcement and measuring the response of the corroding system.We made corrosion rate measurements at nine localized locations where we made the half-cellmeasurements in H e Area 2, and we measured four localized areas where we conducted thehalf-cell measurements in H e Area 1. The test results are shown in Tables 3 and 4.Table 3 - Comparison of Corrosion Rate Measurements with Half-Cell Measurements(HC Area 2)

Test Location 1 2 3 4 5 6 7 8 9Half Cell Potential (mV vs. -400 394 310 -357 476 -410 -248 -353 -236CSE)Corrosion Rate (rnA) 24.64 27.86 0.27 8.22 15.87 13.34 2.56 6.94 0.38Resistance (KOhm) 0.7 0.5 20.5 1.3 0.7 1.0 51.2 3.0 45,7

Table 4 - Comparison of Corrosion Rate Measurements with Half-Cell Measurements(HC Area 1)Test technique 1 2 3 4Half Cell Potential -164 -299 -216 -131(mVvs. CSE)Corrosion Rate (rnA) 0 0 4.27 0Resistance (KOhrn) 54.8 15.9 9.1 21.3

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3 . 5 Ultrasonic TestingWe used ultrasonic testing to determine the thickness of the upper portions of the filter tanksaround their circumference in the upper portion of the tank domes. The tanks are labeled"Paddock Pressure Sand Filters" and are approximately 5 ft in diameter by 6 ft . high. We alsonoted that the west tank appears to be in good condition with no rust present on the outersurface, while the east tank has slight rust staining on the outer surface (Photo 17).For each tank, we took measurements on the dome, at the top of the cylindrical portion of thetanks, and at the dome-to-cylinder junction. We took additional measurements 12 in. below thedome-cylinder junction for the east tank because of the rust staining that we noted. We took 16equally spaced measurements around the circumference of each tank (white X's in Photo 18).We also took measurements at the center of the dome and at various heights along the cylinderas a reference thickness. We were not given any information regarding the initial thicknessesfor the tank walls. The thickness results for both tanks are shown in Tables 5 and 6.


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Mr. Paul S. Brown - Project 070800 ~9 ~ 12 November 2007

( Table 5 -Thickness Measurement of West Tank (In.)Radial Point Location(degrees, 0 6 in. above dome- On tank wall just below 6 In. below dome-towards label) cylinder junction dome-cylinder Junctton cylinder Junction0 0.2447 0.1880 0.1895

22.5 0.2436 0.1930 0,185045.0 0,2387 0.1910 0.185967.5 0.2310 0.1890 0.184990.0 0.2396 0.1896 0.1906112.5 0.2417 0.1915 0.1899135.0 0.2415 0.1910 0.1900157.5 0.2387 0.1910 0.1843180,0 0.2365 0.1909 0.1820202.5 0.2440 0.1888 0.1875225.0 0.2440 0.1918 0.1830247.5 0.2436 0.1825 0.1860270.0 0.2410 0.1874 0.1900292.5 0.2441 0.1893 0.1884315.0 0.2444 0.1910 0.1875337.5 0.2411 0.1856 0.1882Average 0.2411 0.1895 0.1870

Minimum 0.2310 0.1825 0.1820Reference poInt (top center, average of four points): 0.2315Reference point (alon_g_sldeof the shell, average of four points): 0.1842

(Table 6 - Thickness Measurement of East Tank (in.)

Radial Point Locations(degrees, 0 6ln.above At dome-cylinder 6 In. below 121n. belowtowards label) dome-cylinder junction dome-cylinder dome-cylinderjunction junction [unctiono (label) 0.2430 0.1832 0.1803 0.180822.5 0.2370 0.1803 0.1856 0.183645.0 0.2428 0.1840 0.1797 0.184067.5 0.2433 0.1807 0,1822 0.187490.0 0.2383 0.1812 0.1851 0.1872112.5 0.2404 0.1815 0.1837 0.1837135.0 0.2426 0.1830 0.1800 0.1865157.5 0.2403 0.1829 0.1859 0.1840180.0 0.2420 0.1726 0.1850 0.1838202.5 0.2413 0.1840 0.1861 0.1908225.0 0.2377 0.1810 0.1776 0.1865247.5 0.2426 0.1772 0.1776 0.1836270.0 0.2422 0.1806 0.1775 0.1823292.5 0.2400 0.1822 0.1836 not measured315.0 0.2400 0,1650 0.1790 not measured337.5 0.2360 0.1785 0.1770 0.1870Average 0.2406 0.1799 0.1816 0.1851

Minimum 0.2360 0.1650 0.1770 0.1808Reference point (top center, average of four points): 0.2343Reference point (along side of the shell, average of four points): 0.1875


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4 . LABORATORY TESTING4.1 Petrographic ExaminationWe prepared two core samples (C2 and C4) for petrographic examination (visual microscopicobservation and investigation of the concrete by a specialized geologist). We cut a nominal 3/4to 1 in. thick longitudinal section through the center of each core sample (perpendicular to thecrack direction, if applicable.) We then polished the sawn sections to obtain smooth, flat cross-sections for our microscopic examination. We examined the polished sections with the aid of astereomicroscope at magnifications of 4 to 40X. A summary of our observations is presented inTable 7.

Table 7 - Observations of Polished SectionsSample No. Comments

(C2

C4

The concrete is well-compacted with no severe bleeding or segregation ofaggregates.The concrete is not air-entrained.A vertical crack extends along the full length of the core. The crack fracturesoccasional aggregates particles and intersects a small-diameter piece of steel.(Photo 19).There are blue-white soft deposits along the crack ( Photo 20)There is plastic encapsulating the small-diameter piece of steel (Photo 21), andthere are additional plastic masses nearby, suggesting this is a support bar for thereinforcing steel bars.The small-diameter piece of steel is heavily corroded, and partially delaminatesfrom concrete and the encapsulating plastic. Rust is deposited along thecircumference of steel and f ills Into cracks nearby.The paste structure in the bottom 1/8 in. of Core C2 is tinted brown (Photo 22),indicating that the concrete within this zone is carbonated.Air voids In the setting bed mortar are emptyThe smaller voids in the concrete are completely filled with ettringite, while thelarger voids are part ially filled with primary and secondary ettringite (Photo 23)

The concrete is well-compacted with no severe bleeding or segregation ofaggregates.

The concrete Is not air-entrained.There is a 3/4 in. layer of brown-tinted concrete at the bottom of the core (Photo24), Indicating that the concrete at this level is carbonated.The core contains random vertical-diagonal microcracks extent to about 1 in.depth from the bottom surface of the core (Photo 25). The depth of themicrocracks matches the depth of the carbonation.Occasionally, we noted dark rims around aggregates particles (Photo 24).There is a crack inside the aggregate that extends to the matrix (Photo 26).The voids are mostly empty (Photo 27).

We also investigated the blue-whlte soft deposits along the crack in Core C2 using a polarizingmicroscope at magnifications of 25 to 200X. We determined that the deposits are gel fromalkali-aggregate reaction (ASR). The ASR gel filled the cracks and formed succession layersthat correspond to periodic increases in crack width.


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Mr. Paul S. Brown - Project 070800 - 11 - 12 November 2007

( 4.2 Chloride TestingWe analyzed the chloride content of the cores and some of the spalls at four different depthsusing the AASHTO T-260-97 acid-soluble-chloride test method, We determined the sampledepths by first determining the depths of cover (based on either the field testing made with theground-penetrating radar or with the visible location in the cores). We then located the samplesat the uppermost portion of the core, approximately 1 in below the uppermost sample, and atthe level of the upper and lower reinforcing bars. The chloride samples consisted of 1/ 4 in.slices centered on the nominal sample depths. The chloride-ion content for each sample iscalculated on the basis of an assumed unit weight of 145 Ibs/ft3. The results of our testing areshown in Table 8.

T bl 8 R It f Chi 'd C t t T f . C

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a e - esu so on e on en es mgm oresSample Deptht Chloride ContentCore 10 Location (In.) % Ib/yd~

On pool deck south of 21/2 0.107 4,19south pool wall in 3 1/2 0.099 3.88mechanical room.C1 Selected because no 41/2 0.102 3,99visible underside 7 0.111 4,35deterioration.On pool deck south of 2 0.106 4.15south pool wall inmechanical room (below 3 0.122 4.78C2 diving board). Selected 4 0.140 5.48because underside ofdeck delaminated and 6 3/4 0.142 5.56cracked at this location.On pool deck east of east 21/2 0.129 5.05pool wall adjacent to floor 31/2 0.093 3.64drain. Selected becauseC3 underside of deck 41/4 0.099 3.88delaminated at thisiocation. 7 0.184 7.20On east pool wall. 1 1/3 0.041 1.61Selected because no 21/2 0.016 0.63C4 visible underside 31/2 0.012 0.47deterioration. 41/2 0.026 1.02

As m ea sured fro m the to p o f the co re s am ple.We also collected five concrete spalls (labeled A-E) from various locations in the underside ofthe deck and from the north wall. We did chloride testing on spalls B, C, and 0 by cutting a 1/8in. thick piece away from the deepest portion of the spall. The results of our testing are shownin Table 9.

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( a e - esu so on e on en es mg n pa sChloride Content

Spall 10 Location % Ib/yd~A Underside of north plpe-Qallery ceiling. Not tested Not testedB

Near west end of north wall, adjacent0.168 6.58to large soall.C Underside of east pipe gallery ceiflng. 0.149 5.83

0 Underside of storage-room ceiling. 0.624 24.43E Underside of mechanical-room ceiling. Not tested Not tested

T bl 9 R It f Chi ld C t t T f I S II

4.3 Carbonation TestingIn addition to the chloride tests, we also made carbonation tests on the cores and spalls bysawing fresh surfaces on the samples and applying phenolphthalein solution to the freshlyexposed surfaces to observe the depth of any carbonation. The results of our testing are shownin Tables 10 and 11.

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a e 10 - Resu so ar onatlon es mq In tpa sSample 10. Materials Depth of Carbonation Notes

Min (in.) Max (ln.)A Concrete n l a n l a Fully carbonated.B Concrete n l a n/a Fully carbonated.C Concrete n/a n/a Fully carbonated.0 Concrete n l a n/a Fully carbonated.E Concrete n l a n/a Fully carbonated.

T bl It fC b T f . S II

Table 11 - Results of Carbonation Testing In Cores (measured from the bottom surfaceSample 10 Materials

Depth of CarbonationNotesMin (In.) Max (in.)

Concrete 314 1 Partially carbonated.C1 Mortar setting 0 0 Not carbonated.bedConcrete 3/ 8 3/8 Partially carbonated.

C2 Mortar setting 0 Not carbonated.bed Partially carbonated, untilConcrete 3/4 3/4 Immediately above where theC3 rebar located.

Mortar setting

0 Not carbonated.bedConcrete 3/4 1 Partially carbonated.C4 Mortar setting N/A N/A No mortar for Core C4.bed4.4 Evaluation of Heating, Ventilation, and Air Conditioning SystemOn 19 September 2007, Edward G. Lyon of SGH visited Medford High School to review themechanical systems for the natatorium. We were able to make limited visual observations and


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Mr. Paul S. Brown - Project 070800 12 November 2007

( to review original plans stored in the school office that contained some information aboutmechanical system sizing. Drawings HV-12, HV-13 and P-13 show portions of the poolmechanical systems, but these drawings also show a three pool configuration rather than theexisting single pool. We are uncertain if there were other changes to the mechanicalcomponents that are not shown on the drawings. The following summarizes, in part, ourobservations: The pool room is approximately 85 ft by 102 ft with a swimming pool approximately 77ft by 62 ft One end of the pool has an upper deck over the locker rooms that appears to be amulti-purpose space that includes a viewing gallery for swimming events (Photo 28) .. There are two heating and ventilating units over the pool (Photos 29 & 30). Existingbuilding plans indicate the units each flow 7,500 cfm and are set for 50% outside air.Heat is provided by steam from a central plant. There are 4 exhaust fans (exhaust fans F1 to F4) for the pool space. The plansindicate that F1 exhausts 5,080 cfm continuously (Photo 31). F4 exhausts 2,500 cfmfrom the pool space and also exhausts air from portions of the basement. F2 and F3operate intermittently, but there is no indication what triggers their operation. When F2and F3 operate, the two main pool units are to go to 100% outside air. There are no back-draft dampers on Exhaust Fans F2 and F3. We could see daylightat the fan penetrations (Photo 32).( The main pool heating and ventilating units were not running during our visit. ExhaustFan F1 also appeared to be off. We did not determine if Exhaust Fan F4 wasoperating. A small floor fan on top of the pool office was running to circulate air in the

pool space (Photo 33). There are 2 HV units on the upper deck, and there are HV units for the locker rooms(Photo 34). None of these units were operating. There are pool covers at one end of the pool. Dust on the covers suggests that theyare not used routinely. There are 2 thermostats on the north wall of the pool room. The plans indicate thatone thermostat is a night setback. The controls are pneumatic, and one thermostatwas hissing loudly, indicating a possible failure. There was no apparent humiditycontrol.

I The pool water is heated by the building's steam plan! using an in-line heat exchanger(Photo 35). We did not review the water temperature controls. Rain-water drainpipes through the space appear to be well insulated and jacketed withvapor retarders. The insulation and vapor retarders do not appear to extend over theroof-drain bowls (Photo 36). We did not review the roof details. We were told that the roof was recently replaced.


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Mr. Paul S. Brown - Project 070800 12 November 2007( The walls include large areas of plastic glazing (apparently a Kalwall product) (Photo37).

5. DISCUSSION5.1 Visual ObservationsOur visual observations indicate that there is significant ongoing deterioration in the concrete atthe MHS pool. There is extensive spalling and delamination throughout the underside of thedeck and on portions of the east and north walls, indicating that there is widespread corrosion.In addition, there is extensive leakage and efflorescence staining that indicates that the poolwater is penetrating throughout the structure and that any waterproofing offered by the tile andgrout system has failed. This is supported by the delaminations noted throughout the deck.In addition, we noted that there are other ongoing issues of leakage and deterioration in thespace, including apparent leaks from the locker room showers, clogged or broken drains, andsurface staining.5.2 Corrosion MeasurementsOur half-cell and corrosion-rate testing provide an indication of the state of corrosion in the pool.As described in ASTM C876, half-cell measurements can be interpreted according to twomethods, the simplified numeric magnitude technique (NMT) and the potential differencetechnique. We could not use the NMT because of the carbonation, saturation, and exposure ofthe concrete at the pool. Instead, we used mainly the potential difference technique (in whichcorrosion is inferred from areas of rapid potential change and not absolute values), and we useda comparison of the half-cell potentials to the. measured corrosion rates at the underside of thedeck of the north pipe gallery (He Area 3) and east pool wall in the east pipe gallery (He Area1). In combination, the corrosion-rate measurements and resistance measurements suggesthalf-cell potential measurements more negative than approximately -300 mV indicate activecorrosion activity. Figure 4 shows the contour plots for He Areas 1-4; these are describedbelow: The data indicate that very little corrosion is occurring at He Area 1 of the pool wall inthe east pipe gallery, except for a very negative reading in the middle of this areawhere a vertical, leaking, wall crack is located. This indicates that active corrosion islikely confined to this location due to oxygen availabil ity through the crack. At He Area 4 of the north wall at the end of north pipe gallery, many of the readings inthe gallery are unusually positive (11mV to 132 mY); we believe that these unusualreadings do not accurately represent the observed condition of the deck because of the

extensive delamination, carbonation. and advanced corrosion damage in the gallery atthis area. At the left end of the gallery, the half-cell readings are mostly negativereadings (-97mV to -292 mY) indicating no ongoing corrosion. At He Area 2 at the underside of the east pipe gallery deck, our readings againshowed a mixture of positive and negative readings that do not appear to represent theobserved condition of the concrete. These unusual readings likely are caused by thenumerous delaminations and carbonation of the deck and thus do not accuratelyrepresent the condition of the deck.


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( At the underside of the deck of the north pipe gallery (HC Area 3), there appears to besevere corrosion in the left side of the area, where the negative potential readings varyfrom -380 mV to -183 mY. Although the readings at the right side of the area showhigher (Jess negative) potential readings, we believe that they are influenced by thedelaminations and carbonation, and that they do not accurately represent the observedcondition of the concrete.

HC Area 5 (pool wall in the Mechanical Room) exhibits potential readings varying from-329 to 0 mY, with the most negative reading obtained near a vertical wall crack. Thisindicates that there is relatively little corrosion in the pool wall except where oxygen isavailable, similar to our observations at HC Area 1. At our limited readings taken at the localized area around Core C1 (HC Area 6) arerelatively high (-80 to -50 mY), indicating there is little-to-no corrosion in this area. Thelack of indicated corrosion in the reinforcement exposed by the core confirms thelimited indicated corrosion. Our limited readings taken at the localized area around Core C2 (HC Area 7) are verynegative (-411 to -346 mY), indicating there is significant corrosion in this area, Thisindication is confirmed by the severe corrosion observed in the reinforcing steel in theextracted core sample.5.3 SampleRemovalandTesting

( Our observations and testing of the cores and spalls provides information about the overallcondition of the pool deck as described in the following sections.5.3.1 Chloride Testing

Reinforcing steel embedded in concrete is usually protected from corrosion by the naturalformation of a "passive layer" on the steel that occurs when it is in a high pH environment.Ordinarily, this passive layer is stable and allows for the widespread successful use ofreinforced concrete. However, the passive layer can be destabilized by the presence ofchlorides. The typically-accepted chloride-content threshold for corrosion of reinforcing bars inconcrete is approximately 1,2 to 1.5 Ib/yd3.As shown in Table 12, except deep in Core 4 (from the pool wall where no corrosion-relateddistress is present), all of the chloride contents are at or above the threshold required forcorrosion to occur. This generally agrees with the observed heavy corrosion and spal1ing on theunderside of the deck. An exception occurs at Core 2, removed from an intact area on the pooldeck near the office, where little damage is present despite high chloride contents. The lack ofdamage at Core 2 may be related to lack of local oxygen availability or to the presence of higherchloride contents or conditions more favorable to corrosion existing nearby, causing the area toact cathodically,

(


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( Table 12 ~Comparison of Chloride Test ResultsCore Chloride Content Range (Ib/cy) ConditionC1 3.88 to 4.19 No delamination or spa lis; no reinforcement

corrosion.C2 4.15 to 5.56 Delaminations and spafling; significantcorrosion on reinforcing bars.C3 3.64 to 7.20 Delaminations and spalling; significantcorrosion on reinforcing bars.C4 0.47 to 1.61 (highest at outside) No delaminations or spalls; no reinforcingbars encountered.B,C,D 5.83 to 24.43 (highest in storage room) Spalled; significant corrosion of exposedreinforcing bars.

5.3.2 Carbonation TestingThe passive layer can also break down in concrete when carbonation reduces the pH at thereinforcing steel. This process occurs when carbon dioxide in the air penetrates the concreteand reacts with calcium hydroxide in the concrete, consuming it and lowering the concrete pH.Carbonation progresses gradually from the exposed face into the concrete, and the rate atwhich this occurs is typically about 1 mm per year. However, the actual rate of carbonationdepends on the porosity, the moisture content of the concrete, and the carbon dioxide content ofthe air.Tables 9 and 10 clearly Indicate that all of the spall samples that we tested are fully carbonatedand that all the core samples that we tested are carbonated to a depth of 3/8 in. to 1 in.,approximately the depth of cover to the reinforcing steel. This indicates that carbonation of theconcrete could have contributed to the observed corrosion of the steel in addition to thechlorides present (Some studies by others indicate that the chloride threshold is lower incarbonated concrete).5.3.3 Petrographic ReviewOur petrographic examinations of Cores C2 and C4 reveal that the concrete is of generally goodquality. The observed cracks in the Core C2 appear to be caused by a combination of early andlater age drying shrinkage as shown by debris in the cracks and by the fact that the cracksdisrupt both paste and aggregates particles.We observed that the voids in Core C2 are partially or fully filled by ettringite (a sulfatecompound), suggesting that the deck is repeatedly being wetted and dried allowing the water todissolve and redeposit the sulfate materials in the voids. Due to the low water-to-cement ratioof the mortar setting bed, there are no ettringite deposits.The heavily corroded and delaminated small diameter steel confirmed the ongoing severedeterioration. The expansion of the rust produces bursting tensile stress within the concrete,causing cracking and delamination.There are some dark rims around aggregates and fractures extending from aggregates into thematrix, indicating that the aggregates used in the concrete mixture might be reactive. The blue-


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( white soft gel layers along the crack are alkall-slllca-reactlon (ASR) products, which came fromthe nearby aggregates particles through microcracks. This gel deposited along the verticalcrack, and opened the crack due to its expansion when absorbing moisture. The crack did notform as a result of ASR, but the crack continues to widen by the repeated ingress of ASR gelinto the crack. Ingress of water causes the gel to swell and to further widen the crack.In Core C4, we observed that the depth of microcracks matches the depth of the carbonation,indicating that the carbonation process is accelerated by the quick penetration of carbon dioxidein the air through these microcracks. Although we found the dark rims around some aggregatesparticles, and cracks from aggregates extending to the matrix, we did not observe anyindications of ASR (such as gel products) in this core.5.4 Impact Echo (IE)TestingThe impact-echo-test results provide a measure of the slab thickness and of any defects orde!aminations present on the unobservable side ("far side") of the slabs. At the east pool wall,the IE tests are generally consistent, with an indicated pool wall thickness of about 6-1/2 in.Some isolated readings indicate an additional thickness of approximately 7-1/2 in. Theseindications are most likely reflections from the backside of the tile or the inside face of the pooland probably include the thickness of a tile setting bed. The IE tests at the pool also showedmultiple areas where there appears to be a delamination approximately 2 to 2-1/2 in. inside thepool-side face of the concrete wall over much of the lower portion of the pool wall. Note,however, that we were not able to remove a core to confirm the presence of thesedelaminations; it is advisable to confirm these delaminations the next time that the pool isdrained.The IE test results were not clear at the north wall. There were many indications of anunusually thick wall and frequent indications of delaminations in the wall, These readings aredifficult to interpret because no structural drawings of this wall are available that would show therelationship between the wall and the adjacent boiler room. While the IE testing at this wallclearly confirms our visual observations of delaminations and general deterioration of the wall,additional destructive coring or demolition will be required to fully understand the test results.5.5 Pool Filter TanksAlthough we do not have any information about the initial thickness for the dome and cylinder ofthe filter tanks, our thickness measurements suggest that the initial dome thickness wasprobably around 0.25 ln., and that the cylinder thickness was probably around 0.2 in. Based onthis, it appears that there has been minimal loss of dome thickness and of cylinder thickness.There are some slight rust stains on the exterior of the east tank that should be cleaned andrepaired.5.6 HVAC SystemThe existing HV equipment for the natatorium was appropriate for the pool space when it wasdesigned. The equipment is not being operated properly now and is likely past its normalservice life. Current practice is to use equipment that operates continuously to circulate air inthe pool room and to control relative humidity. Often the mechanical-equipment package willinclude provisions to heat pool water with energy recovered from the humidity-controloperations. There are also strategies that allow economical summer cooling of the pool space.


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( Renovations should consider the following: The pool mechanical system should be replaced with equipment specifically designedfor swimming-pool environments. The equipment should be sized to provide a

minimum of 4 air changes per hour in the pool space with an outside ventilation-air rateof 0.5 cfm per square foot of pool and pool deck. New equipment has the ability to heatpool water, but the systems should not be installed without integrating a backup systemfor heating the water. Backup water heating is needed when the dehumidificationsystem is not needed because the ventilation air is sufficient to control pool humidity(typically during very cold weather). Backup water heaters are also needed and sizedto rapidly heat pool water when maintenance requires a water change or rapid increasein pool-water temperature. Pool mechanical equipment should operate continuously to mix air in the space and tocontrol temperature and humidity conditions. Continuous operation will l ikely increaseenergy consumptions over existing operations. Selected equipment should be heavy-

duty construction and have high efficiency. Steam backup water heating can be retained i f steam will remain available year round.If future plans include eliminating steam for pool-water heating, gas water heaters areavailable for pool-water heating. The service life of a gas-fired, pool-water heaterdepends on proper maintenance of pool-water chemistry and appropriate piping andelectrical connections to avoid accelerated corrosion issues.

( New pool mechanical equipment added to the roof will likely trigger structural upgradesto the roofing system to account for Increased equipment weight and drifting snow.5.7 SummaryBecause of the wet exposure of the pool walls and the deck, eventual corrosion of theseelements should be expected. The deck and pool walls have been exposed to water containingchloride ions for many years, and most areas of the concrete now have chloride contentsexceeding the typically accepted chloride-content threshold. Our chloride test results show ageneral chloride content of 4 lb/yd" for core samples, and the highest chloride content we testedis 24 Ib/yd3 for a spall sample collected from the underside of the deck in the storage room. Thelower chloride content in the pool-wall concrete (approximately 1 Ib/yd3) is probably due to itslower permeability (lower water-to-cement ratio) as compared to the pool deck and due to theconstant, rather than the more aggressive cyclic, exposure to the chloride-containing water.Moreover, the underside of the slab and the external side of the pool walls have been exposedto an atmosphere that could cause significant carbonation of the concrete, and the exposure inthe pipe galleries, mechanical room, and storage room has created carbonation depths of up to1 in. The carbonation has reached the bottom reinforcing steel of the pool deck in mostlocations, contributing to the corrosion.In combination, both chloride exposure and carbonation have led to widespread corrosiondamage to the underside of the pool deck, and to some localized areas on the pool wall andeast and north walls.


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(

(

Mr. Paul S, Brown - Project 070800 - 19- 12 November 2007

The visual and delamination surveys of the underside of the deck indicate that there aresignificant ongoing corrosion-related problems in almost the entire pool deck, with ongoingcorrosion causing large spalls and delaminations. There was good agreement between wherewe found high chloride content (Cores C2 and C3) and where we identified undersidedelamination or spalling. Likewise, at areas of low chloride content (Cores C1 and C4) therewas no perceived delamination. It is clear from the chloride content of Core C1 that there arelower levels of chlorides in areas of the deck that have minimal exposure to the pool water, suchas in the office behind the diving boards and outside the office along the south wall. Overall, weestimate that approximately 35%, 55%, 40%, and 70% of the underside of the deck isdelaminated or spalled area in the north pipe gallery, east pipe gallery, mechanical room, andstorage room, respectively. The delaminations in the storage room are presently threateningthe ability of the embedded pipe hangers to support their applied loads, and the loss of any ofthese pipes (lncludlnq the main steam feed into the building) could have severe implications onthe operation of the school building.There are multiple transverse and longitudinal cracks in the pool deck with associatedefflorescence and/or active leakage. Some cracks are at or adjacent to drainpipes with activeleakage surrounding the drainpipes, indicating that the drains are either blocked, broken, orotherwise not functioning as intended.The pool walls are generally in good condition, probably due to the saturated condition (lowoxygen) of the walls from the constant exposure to the pool water. There are a few partial orfull-height cracks along the wall with efflorescence, with a higher concentration of efflorescingcracks at the southeast corner of the pool. There is no apparent active leakage on the poolwal l ,The east wall in the east pipe gallery is generally in good condition, except for a localized 4 ftwide delamination. However, the west half of the north wall in the north pipe gallery has. extensive full-height spall ing and continuous efflorescence along the top of the wall.The majority of the topside of the tile and mortar bed at the pool deck appears to be in goodcondition, with only limited cracking and delamination at the mortar-tile or mortar-concreteinterface. Approximately 139 sf of the deck (6%) is delaminated. The cracks are mostlyassociated with drains, and the standing water at several drains indicates that they are notfunctioning properly. The standing water on the pool deck, the frequent wetting of the pool deckduring use, and the lack of a protective membrane below the mortar setting bed are the likelysources of the efflorescence and of the large chloride contents measured in the mortar settingbed and in some of the concrete.5.8 PrognosisAs described above, the Medford High School swimming pool has undergone a significantamount of corrosion on the underside of the pool deck slab and at localized areas in the poolwalls and east and north walls. For a structure that is nearly forty years old and exposed to ahigh level of chlorides without the benefit of any type of protective membrane below the tile, theamount of distress is not surprising. The present corrosion will continue as the required oxygen,chloride or carbonation, and water can be expected to remain present in the foreseeable future.Therefore, it should be expected that corrosion, spalling, and loss of section of the embeddedreinforcement will continue.


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Mr. Paul S. Brown - Project 070800 20 - 12 November 2007

( In the short term, the present damage can be expected to continue and worsen. The presenceof incipient spalls in the ceiling of the storage room and mechanical room and the loss ofcapacity at the pipe hangers present an immediate hazard that should be addressed because ofthe potential risk to people using the facility and to the operation of the school and pool.Because of this, the school should begin an immediate program of removing incipient spalls toeliminate the falling hazard and implement some type of interim pipe-support system. Althoughthe corrosion has caused some loss of capacity of the deck due to the loss of section of theembedded reinforcing bars, there are no indications of any structural distress that warrantsemergency replacement. We feel that it would be prudent to install some type of temporaryshoring system throughout the under-deck space while the planning for any future work isunderway. These shored areas should be visually inspected for changed conditions quarterlyuntil repaired.In the longer term, the school should anticipate replacing the pool deck within the foreseeablefuture (within 5 to 10 years). We feel this is the only technically appropriate alternative given thedeteriorated condition of the pool structure, the high internal chloride contents, and the school'sdesire for a significant extension of service life. Any replacement deck should incorporate sometype of under-tile waterproofing system to prevent the future intrusion of chlorides. The deckshould also be built with sufficient slope to prevent ponding of splash water. At the time of deckreplacement, any existing cracks in the pool wall should be repaired by epoxy injection, and theconcrete spalls on the east and north walls should also be repaired.In addition, the HVAC equipment in the space should be replaced and upgraded to improve theoverall performance. The following should be considered:

( The design of the recently applied new roofing should be reviewed to ensure that thesystem has sufficient lnsulatlon and vapor retarders to prevent winter condensationinside the roofing system. Although the plastic glazing is tolerant of condensation from a high humidityenvironment during cold winter conditions, there will likely be considerablecondensation on the glazing, and provisions for condensation control may be neededto prevent water damage to other envelope components. Insulation and vapor retarders for the roof drains need improvement to prevent coldweather condensation at the drain bowls. Melting snow and ice on the roof causethese areas to be very cold. Conditions on the upper-deck, multi-purpose space will need to be maintained at thepool-area temperature. Not heating those spaces will cause excessive humidityconditions and potential condensation problems. Pools with spectator areas typically

circulate air at a rate of 6 to 8 air changes per hour. However, more comfortable anddryer conditions could be maintained on this deck if the space is separated from thepool area. Natatorium spaces should be maintained at a slightly negative pressure of 0.05 to 0.15inches water column relative to outside and to other interior locations to control thespread of odors and moisture, Most mechanical systems for pools do not includesufficient capacity or controls to maintain this pressure so additional equipment will .


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( likely be required. The building envelope will also need upgraded air seals to preventexcessive condensation when operating at this negative-pressure level. System controls should be incorporated into the return air system where they can readthe typical air conditions and not be influenced by local sensor location such as can

occur with wall mounting the controls. Return air for the new system should be drawn from an area near the pool deck wherepool humidity will readily enter the ventilation air. Drawing return air from higherlocations tends to stratify dry air. Supply-air diffusers must also jet air to the breathingzone on the pool deck without creating excessive drafts. Often concerns for limitingdrafts at the pool deck compromise air quality by not providing sufficient air mixing inthe breathing zone.6 . CONCLUSIONSBased on our work performed to date and as described above, we conclude the following:1. The pool deck and outer wall are suffering from corrosion-induced delamination andspalling caused by a combination of high chlorides and carbonation in the concrete.Overall, we estimate that approximately 35%, 55%, 40%, and 70% of the underside ofthe deck is delaminated or spalled area in the north pipe gallery, east pipe gallery,mechanical room, and storage room, respectively.

( 2 . There are lower levels of chlorides in areas of the deck that are not as exposed to thepool water, such as in the office behind the diving boards and outside the office alongthe south wall. .3. The delaminations in the storage room are presently threatening the ability of theembedded pipe hangers to support their applied loads, and the loss of any of these

pipes (including the main steam feed into the building) could have severe implicationson the operation of the school building.4. There are multiple cracks in the pool deck with efflorescence and/or active leakage.5. The pool walls are generally in good condition, probably due to the saturated condition(low oxygen) of the walls from the constant exposure to the pool water.6. The east and north walls in the pipe galleries are generally in good condition, exceptfor localized large delaminations.7. The majority of the topside of the tile and mortar b

draft pool report

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