0212071.8 COMMISSIONERS' COURT AGENDA REQUEST MADE BY: Commissioner Williams MEETING DATE: February 12, 2007 OFFICE: Precinct 2 TIME PREFERRED: 10:00 a.m. SUBJECT: (Please be specific).Consider, discuss and take appropriate action to approve a proposed Scope of Work to determine remedial action(s) required to repair Flat Rock Lake Dam. Estimated cost, $18,000. Funds available in Flood control Acct. #22. EXECUTIVE SESSION REQUESTED: NAME OF PERSON(S) ADDRESSING THE COURT: Commissioners Williams. ESTIMATED LENGTH OF PRESENTATION: IF PERSONNEL MATTER-NAME OF EMPLOYEE: Time for submitting this request for Court to assure that the matter is posted in accordance with Title 5, Chapter 551 and 552, Government Code, is as follows: Meeting scheduled for Mondays: 5:00 P.M. previous Tuesday THIS REQUEST RECEIVED BY: THIS REQUEST RECEIVED ON: @ All Agenda Requests will be screened by the County Judge's Office to determine if adequate information has been prepared for the Court's formal consideration and action at time of Court meetings. Your cooperation is appreciated and contributes toward your request being addressed at the earliest opportunity. See Agenda Request Rule adopted by Commissioners Court. ~A ount 22 1 D3-1 DD Piscal Year 2DD6-20D7 Current Account Name NDWACCDUNT General I Balance I Budget' BudgetAdjustments I History I Detail' Account Type Asset ~. Cash Accountlnfo Ca::h Reporting Projects G Dptinnal C" Rb~r~~~' Fiequircd Department Note ~ Lad ~=.heck Numbet Status Active ~ 1. ~ ~ Encumbered D.DD Balance 78,253.17 PmtectedAccount r -` .y. -'~ pending ~ ~ This Record r d Clear ~ V ei w I mindy~~ I Freese °. ctrtd Nichols, Inc. Engineers Environmental Scientists Architects 10814 7otlyville Road, Building 4, Suite 100 January 23, 2007 Mr. William "Bill" Williams Commissioner Precinct No. 2 Kerr County 700 Main Kerrville, Texas 78028 Austin, Texas 78759 512-451-7955 512-451-7956 fax www.freese.com Re: Kerrville Lake Dam, (Flat Rock Dam) Concrete Cap Integrity Investigation Dear Mr. Williams: We are pleased to submit this letter detailing a proposed scope of work for evaluating the integrity of the concrete cap on Flat Rock Dam. Our thoughts have been developed based upon our cursory observance of the dam immediately prior to your December, 2006 Commissioner's Court meeting and subsequent conversations with a firm specializing in ~. non-destructive testing (NDT). The firm is Olson Engineering, Inc. of Colorado. We have worked with the firm in the past and believe they can provide a quantitative assessment of the concrete caps' integrity with the foundation. We are enclosing literature describing two of their potential investigative methods for determining the presence of voids beneath the concrete cap (Attachments A and B). However, these methods are not amenable to working on the submerged face of the dam. Olson Engineering, Inc. is not a dam specialist and therefore, Freese and Nichols, Inc. would work with the information provided by Olson to develop repair procedures and estimated quantities for effecting the repairs. Essentially, once the extent of voids are identified on the crest and downstream slope, we would develop a grouting approach to restore contact between the concrete and the supporting foundation through a grout matrix of cementitious materials or perhaps other fillers. Extreme caution must be exercised when grouting beneath the concrete cap to prevent inadvertently lifting it from the foundation. The upstream concrete slab could be evaluated if the reservoir can be lowered temporarily to allow access to the testing equipment. Otherwise, the grouting procedures will be developed to produce as much flow as possible towards the upstream slab in an attempt to seek and fill any voids under the upstream slab near the crest. The following scope of work is presented and manhours of anticipated effort are developed in an attached spreadsheet. We have not placed pricing along with the manhours. We can easily do so if you determine that this work will not need to be ,~ procured through a solicitation of other engineering firms. Mr. William "Bill" Williams Commissioner Precinct No. 2 Kerr County Page 2 Scope of Services Freese and Nichols, Inc. will render the following professional services in connection with the development of the project: 1. Coordinate the non-destructive testing (NDT) of the concrete cap (crest and downstream slabs above water levels) with firm selected and engaged by the Kerr County Commissioners. 2. Establish survey requirements for layout work necessary for the NDT firm to properly identify their testing sites. The actual survey shall be performed by a firm engaged by the Kerr County Commissioners. 3. Observe the NDT by others. 4. Develop repair procedures for filling the voids identified by the NDT firm. 5. Observe repair grouting and make recommendations of changes when necessary. 6. Coordinate additional investigative procedures if supporting soils are deemed incapable of supporting the repaired slabs. Actual investigations would be by firms engaged by the Kerr County Commissioners. This would likely be a geotechnical engineering firm. 7. Develop repair details for replacing broken segments of the concrete cap. 8. Observe all concrete repairs performed by a contractor engaged by the Kerr County Commissioners. 9. Coordinate with Texas Commission on Environmental Quality (TCEQ) to seek approval of all proposed repair procedures. We are attaching a spreadsheet (Attachment C) which presents our estimated manhours for each of the above tasks. We are available to discuss the proposed approach and can provide some approximate estimates for the work efforts we would expect to be performed by others mentioned above. We sincerely appreciate this opportunity to provide professional engineering services to Kerr County or to provide additional qualifications in the event the work goes out for solicitation. Please call me at 512-451- 7955 if you have any questions or comments. Sincerely, Freese and Nichols, Inc. ~~~~ ~~ M. Leslie Boyd, P.E. Associate Frees and Nic ols, Inc. Stefan chuster, P.G. ATTACHMENT A ..;._'~. I / / / / / ~L i APPLICATION The Ground Penetrating Radar (GPR) method is primarily applied to locate and measure the depth of steel reinforcement, post-tensioning and prestress tendons or ducts, and embedded metallic or plastic conduits in concrete slabs, walls, or structural members. The GPR method is also applied to define areas of corrosion in reinforced bridge decks or other elements, determine thicknesses of members with little or no reinforcement, measure pavement thickness and properties, and locate subgrade voids below concrete slabs or behind retaining walls. GPR scans can be performed on con- crete elements, standard framed or masonry walls, concrete and asphalt pavements, and soil. GPR is used for many~eoohvsical ap l~ications as well. The GPR method is a wave propagation technique that transmits and receives electro- magnetic waves (EM or radio waves). The technology is usually used in zero-offset reflection surveys but can be used in direct transmission. Many antennas are available ranging in center frequency from 25 to 1500 MHz. For NDE applications, the selection of antenna is dependent on the desired feature resolution and depth of penetration and the typical range is 400 to 1500 MHz. /r a GPR Antenna % Also known as: Surface/Ground Probing Radar, Surface/Subsurface Penetrating Radar (SPR). STANDARDS Standards for the GPR method include AASHTO TP-36 and ASTM D6087 for evaluat- ing asphalt-covered concrete bridge decks, ASTM D6432 for general geophysical and NDE applications of GPR, ACI 228.2R for NDE applications in concrete structures, and I AASHTO PP 40, ASTM D4748, FHWA-HIF-00-015, NCHRP Synthesis No. 255, SHRP C-101 and SHRP Catalogue No. 4008 for pavement evaluations. ~ ^ See end of document For full references. ^ ^ ~ - • •~• ~ FIELD INVESTIGATION GPR data are collected in either a 2-D (distance and time) or 3-D (x, y, and time) fashion, depending on the application. The scan patterns for clearing a proposed corehole in a concrete slab for 2-D and 3-D investigations aze shown in the figures below. A i Proposed Corc ' Location ' i ~~i ', i i 1 ~`-w-_e_a_~ T - -'i----'i' i ~t Proposcd Core + Laatoa _ _> t--i --_-i __~`____~ , i ~ ~ 1 r • rt For feature mapping over large areas with little known information, 3-D scanning is typically utilized. A 3-D investigation compiles multiple parallel and perpendiculaz 2-D lines into a panel or panels. 2-D scanning is often reserved for single point locates or for situations in which a good portion of the field conditions are known. ACCESS Only one surface needs to be accessible forthe antenna placement. There are no personnel evacuation requirements with GPR as there are with X-ray (radiography). Scanning along the surface of the test members allows identification of reflection from buried objects along the scan line. The scan path test surface needs to be free of obstacles and debris and clean. A borehole GPR antenna requires typically a 2-4 inch diameter PVC access tube. COLLECTION OF DATA In a GPR test, the antenna is moved continuously across the test surface and the control unit collects data at a specified distance increment. In this way, the data collection rate is independent of the scan rate. Alternatively, scanning can be performed at a constant rate of time, regardless of the scan distance. Single point scans can be per- formed as well. Data is reviewed on-screen and in the field to identify reflections and ensure proper data collection parameters. DATA REDUCTION PROCESSING TECHNIQUES Fora 2-D investigation, features and their loca- tions are identified on-screen and marked in the field. Fora 3-D investigation, data are downloaded either on-site or in our offices to processing clients. The data processing steps may include a variety of geophysical algorithms (initially developed in the field of seismology); the steps performed depend on the data characteristics and project goals. For embedded conduit location, 3-D GPR data are typically migrated and interpolated from scan to scan to produce plan view depth slices, analogous to x-ray images. INTERPRETATION OF DATA GPR tests rely on reflection of electromagnetic waves. The results from a GPR test can be viewed on the screen in terms of a plot of time or depth versus scanning distance (2-D investigation). The two-way travel time is used to calculate the reflector depth assuming that the velocity of the penetrated material(s) is reasonably estimated or known from correlations with destructive coring at selected locations ofthe site. This velocity depends on the material relative dielectric constant. GPR depth calibrations on concrete are often performed from element thickness correlation with Impact Echo (IE) data. Fora 3-D dataset, buried features are identified by viewing plan or perspective views of individual depth slices or a cube/block of data. • .~ • :~~ ~ [Page 2 ~ EFFECTIVENESS The effectiveness of GPR scanning and interpretation is highly dependent on the existing field conditions. Heavily reinforced members may shield radar signals from deeper material or features. Deep, small diame- ter features are more difficult to detect than shallow, large diameter features. Moisture content and clayey materials limit signal penetration. Ambient EM noise may distort data. For depth determination, velocity estimation must be performed from a location of known thickness. Typical accuracies for linear feature centerline locations are t 0.25 to tt.0 inches or less. EXAMPLE RESULTS Examp/e resuks for varfous applications of both 1-D and 3-D scanning: q8 --- - -° s R The results of 3-D scanning to identify poshtensioning (F'TJ tendons in a 12 inch thick elevated concrete floor slob are presented in the figure to the right. The x-trending tendons were spaced at nominally 3 k. A group of four y-trending tendons pass over a column at x = 22-23 fl. The tendons were successfully located and allow For safe coring of approximately 25 holes for a restaurant kitchen remodel: --' --'- -~~7' --_-~~ is '~! .~ - ~ _ . A pair of L7S inch diameter conduits below a 4-6 inch thick concrete floor slab were Found with 3-D GPR scanning at a hospital remodel. The slab varied in thickness from 4- 6 inches and contained a mat of welded wire Fabric rein- forcement with b inch spacing. The 6 inch deep conduits housed critical 4S0 volt power supply lines to the hospital building. The scanning was performed to locate any embedded or buried features ro allow for safe slab cutting of trenches for plumbing installation. Paired 7.75 inch diameter plastic electrical conduits, 6 incites deep below slab. '1 :~~ (Page 3 f EXAMPLE RESULTS COlt t. A 2-f) GPR scan was performed along anew concrete-masonry unit (CMU) perimeter security wall fora country club. The scanning was performed confirm the presence or absence of vertical rebar and to distinguish betweerrgrouted and hollow cells. The results were confirmed with destructive chipping and a repair plan was designed for thewdll. 0 i c w 3 H e~ O rn v ti 2 a' O_ a Iw n S Ground Penetrating Radar [GPR] Results far Alpine Dam Spillway Slab Impulse Response [Slab IR] Relative Mobility Resulb for aeiauve MRbiiily ~~s -R for Alpine Dam Spillway IMeanavaiuetw GPR was combined with the Slab Impulse Response (Slab IR) method to locate sub- grade.voids bebw an alpine dam spillway (seereferences for full text). ,N F+ B ~ =~ ~ l• r "" r. ~.F3~ ~~, -~} - ~}~'~~ s=~~/ > s° r ~~ a 15'1 I~ ,~ ,~ 1A r m „z ,~ € ,6 1s ~~ o zo rn n g 61 56 15 qp 10 30 I6 5 0 1 w~a Mean (Page4J S7e.«:,.~7 .eti~. DISTANCE [FOOT] Hollow cells Grouted cell and missing rebaz L6 Lr LE C fQ Rr R6 11 tl Ifi :4 3$ 40 48 Eaa~nglro EXAMPLE RESULTS CORt. A 3-D GPR investigation was performed on an outdoor concrete parking (oi aker isolpted cracking had occtirred upon heavy vehicle/machinery kwding. The slab thickness for-each scan was semi-automatically identified and exported from the GPR processing sofM~ctre. The tabulated data were then contoured. The slab design thickness was b inches and tfie full western 40 feet was designed to be 8 inches. The critically thin threshold was designated as d inches. SLAB THICKNESS GPR RESULTS 0 10 20 30 90 50 60 )0 80 90 100 110 120 130 190 150 160 1)0 180 190 200 210 220 230 290 250 260 2T1 2W 290 3W 310 320 330 220 Zt 210 200 cmmua sbn ruat.a.. Pn.l .. 1 1 190 180 10 .~~.. 19 1l0 9 85 A M O 1 1 t60 150 g A 1 190 ) 5 p 13 130 ) q 1 11 Buildin gllandsca ping Footprint 120 110 6.5 6 ys t0 100 55 W 0 5 U G ~ ) 0 ]0 • 45 ' u 6 0 , 9 ' Q 0 l ; 3 5 3 30 25 20 1 10 w w! Y, a 7777 0 10 20 30 90 50 60 70 80 90 100 I30 120 130 190 150 160 IJO 180 190 200 2t0 220 230 290 250 2W 290 2W 290 300 310 320 330 a Distance Easl of West CnrD (tt.) • • i~~ ~ [Page S] FIELD INVESTIGATION 32)61 126) }6U S1Q 2)11 tag) 21 )] 1921 1690 IIJ1 1265 106] B]) 893 513 33] X63 -a -t]9 -351 -525 -]01 -861 iu65 -1255 Is53 -1659 -~e)B -T t2 -2365 -2665 -2962 -}J35 -Jam -+s55 -3.2 ]fi) 1 =g F ~ Results from GPR 4ests performed on runways and taxiways of an airpoif to determine the thiclmess of the asphalt layers: The antenna was mounted tq a van trailer hitch for fast data collection. 1]1%TA\f'F CFO (1 T~ GPR xanning was per- formed at the hose of a wall to locate steel- wrapped concrete founda- tions (caissons) behind the wall. The results of 2-D scanning are presented in the figure to the right. i~ a .: ~. c x s Bk-28L, 12 k L • ~~ • :~~ • [Pageb] ~} W(Iwlle~ lbO ~~Ib~ ~} ~ .1 a.v~.a 1+1n {; Standards and Governmental Reports ^ AASHTO PP 40, "Application of Ground Penetrating Radar (GPR) to Highways". ^ AASHTO TP-36, "Standazd Test Method for Evaluating Asphalt-Covered Concrete Bridge Decks Using Fulsed Radar". ^ACI 22S.2R, "Nondestructive Test Methods for Evaluation of Concrete in Structures", ACI Manual of Concrete Practice, Part2, Construction Practices and Inspection, Pavements, ACI International. ^ASTM D4748, "Standazd Test Method for Determining the Thickness of Bound Pavement Layers Using Short-Pulse Radaz", Book of Standazds Volume 04.03, ASTM International. ^ ASTM D6087, "Standazd Test Method for Evaluating Asphalt-Covered Concrete Bridge Decks Using GROUND Penetrating Radaz", Book of Standards Volume 04.03, ASTM International. ^ ASTM D6432, "Standazd Guide for Using the Surface ,,,,_ Ground Penetrating Radaz Method for Subsurface Investigation", Book of Standards Volume 04.09, ASTM International. ^ FHWA-HIF-00-015, "Ground Penetrating Radaz for Measuring Pavement Layer Thickness". ^ NCHRP Synthesis No. 255, "Ground Penetrating Radaz for Evaluating Subsurface Conditions for Transportation Facilities", A Synthesis for Highway Practice, TRB Synthesis Studies. ^ SHRP C-101, "Condition Evaluation of Concrete Bridges Relative to Reinforcement Corrosion", Vols. 1-8. SHRP Reports 5-323 through 5-330. ^SHRP Catalogue No. 4008, "Pavement Thickness Softwaze Using Radar". OLSON ENGINEERING PUBLICATIONS ^ "Application of a Combined Nondestructive Evaluation Approach to Detecting Subgrade Voids Below A Dam Spillway", Larry D. Olson, P.E., David A. Hollema, Environmental and Engineering Geophysical Society (EEGSI, Symposium on the Application of Geophysics to Engineering and Environmental Problems ISAGEEP~, presented at Colorado Springs, Colorado, February 23, 2004. ^ ^ ^ OLSON ENGINEERING, INC. Corporate Office: 12401 W. 49th Ave Wheat Ridge, CO 80033 USA Phone: 303.423.1212 Fax: 303.423.6071 • www.olsonengineering.com • www.olsoninstruments.com • Idolson@olsonengineering.com New York Office: 1501 Broadway, Suite 310 New York, NY 10036 USA Phone: 212.302.8674 Fax: 212.302.8676 • agibson@olsonengineering.com ATTACHMENT B I APPLICATION Slab Impulse Response (Slab IR) investigations are performed primarily to identify subgrade voids below slabs-on-grade. The method is excellentfor evaluating the repair of slab subgrade support conditions by comparing the support conditions before and after repairs. The elements that can be tested include, concrete slabs, pavements, runways, spillways, pond and pool bottoms, and tunnel liners. The Slab IR method is often used in conjunction with GPR for subgrade void detection and mapping. In addition, the Slab IR test method can be used on other concrete structures to quickly locate azeas of delamination or void in the concrete, if the damage is rela- tively shallow. Slab IR can be performed on reinforced and nonreinforced concrete slabs as well as asphalt or asphalt-overlay slabs. The schematic below shows the field setup used in Slab IR investigations. Impulse -.: Ha~ Freedom NDT PC Geophone SLAB IMPULSE RESPONSE SYSTEM STANDARDS Standards for the CSL method include ASTM D6760-02 for integrity testing of con- crete deep foundations and ACI 228.2R for NDE applications, and FLH 521.830 for determining pulse velocity through concrete in drilled shafts. See end of document for full references. ^ See end of document for full references. ~ • •~• ~ FIELD INVESTIGATION ACCESS The Slab IR method requires access to the top surface for receiver locations and ham- mer hitting. The receiver is mounted to the surface of the slab adjacent to the impact location and generally 3-4 inches away. COLLECTION OF DATA In a Slab IR investigation, the slab top is impacted with an imgulse hammer and the response of the slab is monitored by a geo- phone placed next to the impact point. The hammer input and the receiver output aze recorded by an Olson [nstruments Freedom Data PC e ui ped with the Slab Impulse ne...,,.....a ~.,..~a.., ~~,a ,. ,., e..m access be per- [Paget) DATA REDUCTION PROCESSING TECHNIQUES Fast Fourier Transform (FFT) operations per- formed by the Slab IR softwaze in our Freedom Data PC transform the impulse force and vibra- tion velocity response time domain signals to produce a plot of mobility (vibration velocity/ pounds force). After transformation to the fre- quency domain, the transfer and coherence curves are automatically generated by the Freedom Data PC Slab IR softwaze. Analysis of the mobility plot provides information on the subgrade support conditions within a radius of 0.5 to 1.0 foot from the test point depending on slab thickness. INTERPRETATION OF DATA Support condition evaluation includes two measurement parameters. First, the dynamic stiffness is calculated. The initial slope of the mobility plot indicates the quasi-static flexibility of the system. The steeper the slope of the initial part of the mobility plot, the more flexible and less stiff the system is. Second, the shape and/or magnitude of the mobility plot above the initial straight line portion of the curve is an indication of support condition. The response curve is more irregulaz and has a greater mobility for void versus good support conditions due to the decreased damping of the slab vibration response for a void. The presence of a high- amplitude, low frequency spike in the mobility plot is an additional indication of void conditions. EFFECTIVENESS The Slab IR method is used to determine the sup- port conditions of the slab and to map out the aerial extent of any void or poor support condition zones, but the method cannot determine the thickness of any voids found. Collecting Slab IR data at multiple, densely-spaced locations can improve the conclu- sions by mapping relative areas of higher and lower mobility. However, relatively low mobility does not indicate the absence of a subgrade void, but quali- tatively indicates that such an area appears to be more solidly supported than an area with relatively high mobility. For thick slabs (thickness > 2 ft), the interpretation of the Slab IR data becomes difficult because the stiffness of the system is controlled by the slab itself and not by the support conditions under the slab. [Page3] EXAMPLE RESULTS fo illustrate the concepts of the Slab IR test, example results from an investigation performed on a highway entrance ramp are presented below. The images show the resulting mobility profile for the ramp. The color scale is read such that white space equates to low mobil- ity and green equates to high mobility. Mobility corre- sponds with flexibility. The Flexibility is represented by the blue diamonds, the larger the diamond the larger the higher the flexibiliy (refer to page 5~. ' ~ r .. ..... ... . - - ~ ~~ The figuGe shows mabeliy forvoid arrc#;sound subsuefaee con- ditions, respectively. Fn both cases, the upper curves for Coher- ence indicate good: data quality. [ Page a ] EXAMPLE RESULTS CO )i t. The example is a technique used to produce an image or contour map of the data collected. When analyzing data collected on a particular site, clear results will appear much like the figure below. Good subgrade support will result in high coherence and low mobiliy, poor subgrade support will result in high coherence and high mobiliy. The image below is of good subgrade support, the image on next page is of poor subgrade support. The coherence is related to the coupling of the transducer to the member. This can bean indication of poor coupling if the coherence is poor. Evidence of water nFiltration rousing butging AAechanically Stabilized Earth (MSE) wall correlates to area of high relative mobiliy. 40 -260 .~ Dice t~U SLAB IMPULSE RESPONSESLAB IR) RESULTS FLEXIBILITY~MOBILITY PLOT MoEl1ily (INaAb) ,.. a« :«.a.~ ~. ~~r ,~ oa taaa ,+r w ~~ m. ~.~ ~~. o.. ~..~ Cq W1 : Qan n~ri+.el /.zEaot b zoemr z.oe.ao~+ eo zae.oor zsc-am m S Senor • S.SEOOr b ! SEOd7 • ! 7FGG7 fe 1 K.006 [ Page 5 j EXAMPLE RESULTS COYt t. Y C3roWr„~t{~P,~pg~rgtin~itadrir (GPR) wrs tom. bins with the Skb tipppfse Response, (Stab Itd}"riiiathOd~lo latate sulgrt~€le roils l5elow _ .s _ $ W x 15R _ ~ IM _ 9 - ,~>s _} x - ` 1~ x 1Z1 a(m~~,.alprr~ prnn 5p~lway(SC8 refere{1Ces !Or _g a a 112 n 5U5]t~l.. _ 10! _° @e6n a o ~ m _ - s _- Q n /~ ~i!F = a j 'b~ _ F: V ~ ~ { / _ /a ` Yti.. I _ = ~.~_ R - 16 5 e =_ - e a 5 y B"'~ t6 t1 52 C R2 RI R6 w ~ 5 0 0 I6 3a 52 a0 a0 a eamne(R) Relatlve Modlily (NOrmalis0[o Mean Value) z I Mean [ Page 6 ] REFERE OLSON ENGINEERING PUBLICATIONS ^ "Application of a Combined Nondestuciive Evaluation Approach to Detecting Subgrade Voids Below a Dam Spillway," Hollema, David A., Olson, Larry D. 120041 SAGEEP 2004. N ENGINEERING, INC. ~ 5191 Ward Rd., Suite 1 Wheat Ridge, CO 80033-1936 USA Phone: 303.423.1212 Fax: 303.423.6071 • www.olsonengineering.com • www.olsoninstruments.com • Idolson@olsonengineering.com ~ ^ ^ ^ OLSO ATTACHMENT C ATTACHMENT C Flat Rock Dam Kerr County, Texas Concrete cap integrity evaluation Manhour Estimates Freese and Nichols Services Hours Task Descri lion Princi al Pro' M r En r IV CADD Geol Clerical Ex enses 1 Coordination NDT 6 2 1 2 Estab survey req'mts 4 1 4 1 3 Observe NDT 24 8 4 Develop repair proc. 8 2 2 2 5 Observe grouting 24 8 8 6 Coord add'I invest. 1 4 2 1 7 Develop conc repair proc. 8 2 4 8 Observe conc repairs 16 8 9 Coord with TCEO 4 2 1 Totals 1 98 29 10 14