W912P823R0041 Amend 0002 Appendix E- Control Structure Stilling Basin Inspection No 09 (October 1987).pdf

MISSISSIPPI RIVER AND TRIBUTARIES

OLD RIVER

LOW SILL CONTROL STRUCTURE

STILLING BASIN

AND GATE RAIL

INSPECTION

AND REPAIRS

REPORT NO.9

US Army Corps of Engineers New Orleans District

INSPECTION AND REPAIRS CONDUCTED: MAY - OCTOBER 1987

DATE OF REPORT: MAY 1988

OLD RIVER LOW SILL CONTROL STROCTURE

1987 STILLING BASIN AND GATE RAIL INSPECTION AND REPAIRS

REPORT NO. 9

DATE OF INSPECTION AND REPAIRS: MAY - OCTOBER 1987

DATE OF REPORT: MAY 1988

U. S. ARMY CORPS OF ENGINEERS

NEW ORLEANS DISTRICT

Section

Number

I

II

III

IV

V

VI

OLD RIVER LOw SILL CONTROL STRUCTU~E 1987 STILLING BASIN AND GATE M.IL INSPECTION .A..>ilD REPAIRS

Table of Contents

Title

In trod lC tion 1987 Ins pec tion Inspection Results Repairs Conel usions

Appendices-

Title

Photographs Discharge Diversion Ratio Curves - Auxiliary Structure Narrative Completion Report on Contract N>. DA(l.l29-87~-0l24 And Memoran:iuu Thereto High Bay Support Rail Inspection High Bay Upstrean Needle Seat Recesses Inspection Org ani za t ion Char t

Number

OLD RIVER LOW SILL CONTROL STRU:::TURE

1987 STILLING BASIN AND GATE RAIL INSPECTION AND REPAIRS

Table of Contents (Continued)

Plates

Title

IDeation Maps South Half of Strocture-Plan (As Built) Sections (As Buil t) Locations of (1973) Scour Hble IDeation of Instrumentation Location of Instrun.entation Northside High Bay Inspection Low Bay Inspection s>uthside High Bay Inspection Stilling Basin Repairs Baf fIe Block Inspection - Nos. 1 To 12 Baffle Block Inspection - Nos. 13 TO 27 Baffle Block Inspection - Nos. 28 To 40 Baffle Block Inspection - Nos. 41 TO 53 R:lil Repair Closures (As B.lil t) Rail Iepairs Sand Closure - Plan Sand Closure Sections and DaW3.tering System OUtflow Channel (Pre Construction) Outflow Channel (Post Constroction) Da W3.tering Pie zaneters Piemmeter Dita

SECTION 1 - INTRODUCTION

1-01 Purpose and Scop:!.

This report docunents the fin:iin~s of the 1987 inspection of and repairs to the Old River lDw Sill Structure stilling basin and gate rails. It contains the results and conclusions fro~ the inspecticn which incl uded a general condition inspection of all structural features downstream of the (closed) struc ture gates while in a dewa tered condition, and an underwater inspection of the upstream needle seGt recesses in the hi~h bays.

1-02 Datun.

All elevations, ex.cept where otherwise indicated, are in feet and refer to National Geodetic Vertical futum of 1929 (NGVD), fonnerl? mean sea level (MSL).

1-03 Previous Reports and Related Documents.

a. Previous Reports. The Old River lDw Sill Control Struc:ure stilling basin has been ins pee ted since 1976 and the inspection reports are contained in the following:

Report Report Number Title )ate --

1 Underwater Stilling Basin Ins pec tion (1977) Aug 1977 2 Underwater Stilling Basin Ins~ction (1978) Nov 1978 3 Underwater Stilling Basin Ins pee tion (1980 /81 ) Apr 1982 4 Underwater Stilling' Basin Inspec tion (1982) Nov 1983 5 Underwater Stilling Basin Ins pec tion (1983) Nov 1983 6 Underwater Stilling Basin L'lspec tion (1984) Nov 1984 7 Underwater Stilling Basin Ins pe~ tion (1985) Jan 1986 8 Underwa ter Stilling Basin Inspection (1986) Apr 1987

1-1

b. Related Documents. The following documents relate to the dewatering and inspection of the Low Sill stilling basin and gate rails:

(1) Supplement No.1 to ill No. 12, Old River ww Sill Control

Structure fuwatering Analysis and endorseuents theretl).

(2) LMNED-DD letter dated 4 February 1987, FC, MR&T, Old liver

Control, wuisiana, Low Sill Structure, Dewatering

Analysis, Final fusigns and endorsements thereto.

(3) L~~ED-DD letter dated 26 February 1987, Mississippi River and Tributaries, Old River Control, Review of Plans a:l.d

Specifications for Low Sill Control Structure, fuwaterin~, Stilling Basin and Rail Repairs and endorsements thereto.

(4) L~~ED-FS letter dated 9 March 1987, Mississippi River and

Tributaries, Old River Control, Evaluation of Abut:nent

Seepage for Low Sill Control_ Structure, fuwatering, Stilling Basin and Rail Repairs and endorsements thereto.

(5) L~~ED-DD letter dated 2 May 1987, Safety Monitoring and

Survey Activities for the Old River Control Structures during the Low Sill Structure Dewatering, Stilling Basin and Rail Repairs and endorse~ents thereto.

(6) WES Technical Report NO. 3-602 dated June 1962, Review of

Soils Design, Construction and Perfor~ance Observations wW'-Sill Structure, Old River Control.

1-04 Location and Description.

a. The Low Sill Control Structure is located on the west bank of the Mississippi River between Mile 314 and l1ile 315 above the Head of

Passes and together, with the Auxiliary and Overbank Control Structures, provides for the control of flow from the Mississippi River into the

Atch.'ifalaya Basin. See Plate L 1-2

b. The structure complex (see Plates 2 and 3) consists of the reinforced concrete control structure, an 'inflow channel from the

Mississippi River, and an outflow channel to the Red River. The structure is founded on steel piles, has a gross length of 566 feet between abutments, and consists of 11 gate bays, each having a 44-foot clear width between piers. The three center bays have a weir crest elevation of -5.0 and the four outer bays on each side of the center bays crest at elevation +10. O. Flow through the structure is regulate1 by steel vertical lift gates which are handled by two traveling gentry cranes. A 26-foot wide highWlY bridge is located on the downstream. side of the struc ture and is part of Louisiana State Highway No. 15.

c. The stilling basin is a concrete channel with a width of

566-feet near the downstream edge of the piers and wi th a 1 on 8 flare to a width of 592-feet at the end sill. The central portion behind the three deep center bays is lSO-feet wide wi th an orig ina1 floor elevation of -12.0 and terminates with an end sill at elevation -9.0. The side portions behind the four outer bays have an orig inal floor elevation of

-5.0 and terminate in an end sill at elevation -2. O. Two rows of staggered baffle blocks 10-feet high orisina1ly and 12-feet apart are provided across the stilling basin. As a result of the repairs performed during this inspection, the three deep center bays have a floor elevation of -11.0, the side portions behind the four outer bays have a floor elevation of -4.0, and the baffle blocks are 9-feet 'ugh.

d. Due to irreversible foundation danage to the U:Yw Sill

Structure during the flood of 1973, construction of the Amd1iary

1-3

Control Structure 'iAS authorized in Q!tober 1979, begun in Q!tober 1981 and conpleted in Septenber 1987. The structure began initial operation in ~cenber 1987.

1-05 Pertinent Data.

Pertinent data are tabulated below: 1/

Low Sill Control Structure

Gross width between training walls

Clear width at weir

Leng th of still lng basin lDw flow bays (Bays 5-7)

Weir bays (Bays 1-4, 8-11)

Bottom of inflo channel at structure

566 feet

484 feet

99 feet

104 feet

Low flow bays -5.0 feet NGVD

Weir bays 0.0 feet NGVD

Weir crest or sill lDw flow bays - sill

Weir bays - weir

Low Sill Inflow Channel

Length (approximate)

Bottom width

Bottom elevation

Low S 111 Outflow Channel

Length (approximate)

Botto.:n width

Bottom elevation

1/ As - construe ted val ues

1-4

-5.0 feet NGVD

10.0 feet NGVD

2,200 feet

1,000 fe!t

-5.0 fe!t NGVD

7 miles

900 feet

-8.0 to -10.0 feet (NGVD)

1-06 Operation of Structure Since Last Inspection.

The last inspection of the stilling basin was performed in ~ugust

1986. The inspection and necessary rehabilitation work was comFieted 22

August 1986. Since that inspection, the IDw Sill Control structu:e was operated by maintaining the 70-30 percent flow distribution of to~al latitude flow.!! between the IDwer Mississippi River and the Atchafalaya

River. On 18 September 1986, a gate setting limitation was placed on

Gatebays 5 and 7 at the IDw Sill Control structure due to danaged or missing gate rails in these bays. Gatebay 5 was limited to an 18.8 foot opening or larger and Gatebay 7 was limited to a 24.8 foot opening or larger. On 22 December 1986, the Auxiliary Control Structure went on line and was operated ~n concert with the IDw Sill Control structure according to Ratio 1 (see Appendix II) to maintain the 70-30 percent flow distribution. The peak latitude fl?w during the period 22 Po:Just

1986 to 14 May 1987 was 1.391 million cfs (14 March 1987) comparej to the 1973 record level of 2.261 million cfs.

other hydrological statistics of importance since the last inspection include:

.!! "'lbtal.latitude flow" is defined as the total of the flow of the Mississippi River at Tarbert Landing and the flow in the Atchafalaya

River at Simmesport, Louisiana. The 70/30 flow distribution refers to the respective percentages of the total latitude flow conveyed by the

MLssissippi River below Old River Control (70 percent) and the

Atchafalaya River (30 percent).

1-5

1936-1987 Low Sill and Auxiliary Operating Statistics Iten Magnitude HW TW Date

L. S. Aux. L. S. -Aux. L.S-. Aux. L. S. Aux •

Max Q "" 301 86 45.8 45.7 34.3 32.1 22 Oct 86 25 Dec 86 (1000 CFS) 170 106 43.5 42.8 30.4 30.4 29 Apr 87 1 May 87 t1ax Stages "" 47.2 46.1 33.0 33.1 18 Dec 86 23 Dec 86 ( ft NGVO) 50.2 49.6 34.8 34.9 15 Mar 87 15 Mar 87

Highest ~~' s 15.9 14.4 39.95 40.1 24.05 25.7 3 Dec 86 31 D::!c 86

(ft) 16.55 15.95 43.6 43.1 27.05 27.15 3 Apr 87 3 Apr 87

A summary of surveillance since the last inspection is as follows:

a. All permanent piezo~eter readings were within anticipated ranges. For the dewatering project, 18 piezometers were specifically installed in order to closely monito~ the uplift pressure on the stilling basin slab. Piezometer iastallation commenced on 18 May 1937 and was co~pleted on 30 May 1987. Piez~eter data gathered throughout the dewatering is presented on Plate 22 and includes the 18 (dewatering) piezometers, B-9, B-11, RP-6, RP-10 and RP-11. Sampling during piezometer installation confirmed the extent of the scour damage during the 1973 flood and the subsequent grout repair. See Plate 21 for piezometer and grout locations. Readings from and installation reports for piezometers RPB-l1 and RPB-14 verified that some damage was sustained by the upstream stilling basin sheetpi1e cutoff resulting in some loss of filter material upstream of the baffle blocks behind

Gatebays 3, 9 and 10. Long term pumping of the drainage blanket verified that, with the exception of the small aforenentioned area, the drainage blanket was functioning properly. This pumping was first accomplished by utilizing the manholes and through their interconnection with the drainage blanket (the collector pipes), relieved the excess uplift pressure beneath the slab. When dewatering of the low bays

1-6 corrunenced, pumping of the inspection hole in Baffle Block No. 28 was used. '!hrough the use of a single punp (with a backup on standby in the inspection hole in Baffle Block No. 27), the entire drainage blanket was efficiently punped. Pie zaneters RPB-11 and RPB-14 were eventually incorporated into the permanent structure instrunentation and, in conj unction with the existing stilling basin piezaneters (RPS-6, RPS-8, B-9 and B-11), will give an accurate representation of pressures beneath the stilling basin slab.

b. All hydrographic and overbank (land) surveys in the inElow and outflow channels of the Low Sill indicated that the channels have remained stable. See 5-03 for additional information regarding the outflow channel subsequent to th dewatering.

c. Alignment and level surveys for the structure monolith; and guide walls have been within normal ranges while in operation. During the dewatering, survey results fell within anticipated limits.

Subsequent to dewatering, survey results returned to previously ~ccepted ranges. Prior to the dewatering, tilbneters were installed on the stilling basin wall monoliths. See Plate 5 for locations. '!hese tilbneters display the angle at which the tilbneter is positioned in hundredths of a minute of arc and were used in conjunction. with the conventional alignment surveys to monitor these soil founded wall monoliths. No ananalous readings were recorded during or subsequent to the dewatering, and no unusual structure movenents or adverse effects were observed.

1-7

d. Another operational problem, sim ilar to that reported in the previous report, developed prior to closing the !ow Sill structw:e.

en 10 May 1987, just 4 days prior to closing the !ow Sill Structure for the dewatering, a second rail failed. Unlike the first failed rail

(described in Report ID. 8) ...tlich was a dOWlstream support (treac) rail in Gatebay 7, this second fail ure was of an upstream guide rail in

Gatebay 5. This failure did not restrict the closing of the structure.

1-8

SECTION 2 - 1987 INSPECTION

2 -01 I ntroducticn •

The inspection was performed during the execution of the contract to dewater and repair the stilling basin and to rehabilitate the vertical lift gate support rails. The contract was awarded to

Ai Johnson Construction (b. and Massnan Construction (b., a joint venture on 8 May 1987 under contract number mCW29-87-C-0124. A list of sUbcontractors is included in the narrative completion report provided in Appendix III. The first notice to proceed was issued on 13 May 1987 with final completion accepted on 13 October 1987. '!he approxima.te cost of the contract was $6.35 million.

'!he contract was administered at the site by the Lafayett Area

Office Administrative personnel including the following:

(1) Albert F. Res weber GS-12 Proj ect Engineer (2 ) Ronald G. Legendre GS-12 Assistant Project Engineer (3 ) Michael F. Hullihan CPr Deputy (4 ) Harold E. Manuel MAJ Deputy (5 ) Stephen B. Hinkcmp GS-11 QUality Assurance

Representative (6 ) I))nald J. Guidry GS-11 Office Engineer (7 ) welton T. Le Blanc GS-9 Construction Represantative (8 ) Inspectors (five, varied)

Due to the sensitivity of the work to time, an engineering team was mobilized to the site to minimize any delays to the contract. The

NOD engineering team consisted of the following personnel:

(1) Thomas G. Hassenboehler GS-12 Des Br Engineering Di.v is ion Representative

(2) John B. Grieshaber GS-12 F&M Br Foundation Engineer

(3) Gerard Giroir, Jr. GS-11 Des Br Structural Engineer

2-1

(rotated with other structural engineer)

(4 ) Cary D. McNamara GS-11 Des Br Structural Ehgineer (rotated with other structural engineerl

(5 ) Kim J. Tullier G3-11 HiM Br Fbundation Engineer (at night during critical dewatering period)

(6 ) Gary T. Herndon G3-11 HiM Br Surveillance Technician ( rota ted wi th t w) ober technician s)

(7 ) Thomas G. Waguespack GS-11 F&M Br SUrveillance Technician (rotated with tw) obler technicians) (8 ) John M. Interanto G3-9 Des Br Surveillance Technician

(rotated with tw) other technician s)

(9 ) Rotating 9.lrveillance Team Members ( cne person)

The organization chart for this contract is contained in Appendi~ VI.

other NOD personnel supporting the project were site personnel fran Survey section, ~erations Division, O:mstruction Division and lafayette Area Office. The SUrvey Section personnel were required to furnish field data during the intensification of surveillance throughout the inspection period. Operations Division site personnel were required for the following: (1) gate changes at the Auxiliary structure

(2) gate movements at the lOw Sill structure, (3) miscellaneous fabrication work, (4) field procurements, and (5) other duties as field conditions dictateq. Construction Division and lafayette Area Office personnel were responsible for oversight of contract administration. In addition to NOD support personnel, Mobile District personnel and equipment mobilized to the site and installed the eighteen dewatering pie zometers disc ussed in 1-06. a •

2-2

2-02 Scope of Work.

The Engineering Division Representative and the two Structural

Engineers perfor:ned a general condition survey (inspection) on the portion of the ww Sill stilling basin downstream of the vertical lift gates in the dewa tered condition. The inspection was to review the results of the previous underwater inspections and repairs, and to correct any inadequacies found. Most imp:>rtantly, repairs to gate hardware and the stilling basin floor were kmwn to be needed, although the complete extent was not. Since the stilling basin was ladened wi th silt, areas were inspected in the order in which they beca'1le uncolered.

The inspection was not a detailed crack survey but rather a general overview to (a) canpare the results with previous underwater stilling basin inspections, (b) determine the necessi ty for repairs beyond those deter:nined to be necessary in prior underwater inspections, (c) establish a new baseline condition for coollarison wi th resul ts of future inspections and (d) assess the reliability of the stilling basin to perform as intended. It should be noted that the area downstream of the end sill was not conpletely free of debris, standing water and equip:nent as evidenced by various photographs accoolI:a.nying this report.

2-03 Structure Opera tim.

At the start of the inspection, the lDw Sill Control Stru:ture was opera ting in a combination orifice flow, uncontrolled flow and hll gate closures. L'1 order to close all of the gates at the Low Sill Struc ture, the delta head on the structure had to be re.1uced below 10.0 feet. To achieve this redu:ed delta head, the Auxiliary Stru:ture was opened to a maxinu;n opening of 25 feet with an approxinate maxinum discharge of

1 80 , 000 cfs.

2-3

SrAGES Location Maximum Minimum

Knox land ing* 34.20 (10 Jun) 15. 20 C 4 Oc t) Sim::nes por t* 15.65 (14 Jun) 3. 90 (13 ex: t) Head W3. ter* 34.60 (10 Jun) 15.45 C4 Oct) Tailwater* 19.65 (11 Jun) 8.80 (L4 ex: t) Delta Head* 16.15 (19 Jul) 6.65 (L4 Oct)

* A'1 Reading 0600, 0630, or 0700

During the dewatering period (14 May - 14 October 37), the

Auxiliary Structure WlS opera ted alone to ;naintain the 70/30 flow distribution with no extraordinary proble-ns. The lllaximun and minirnun flows during this period were 144,000 cfs (15 May 1987) and 55,0;>0 cfs

(13 Jct 1937) respectively.

2-04 Surveillance.

The level of surveillance deviated from those specified in the previously used level of surveillance chart. This departure WlS described in the letter referenced in l-Q3.b.(5).

SOOle scour was detected in the Auxiliary Structure Channels.

Complete details will be included in the Auxiliary Structure Operational

Test Plan report presently being prepared by IDD.

2-4

SECTION 3 - INSPECTION RESULTS

3-01 General.

Unlike the previous underwater inspections, this inspection was performed while the portion of structure located downstream of the vertical lift gates was in a dewatered condition. The dewatering ~as essential for the placement of an overlay of the stilling basin slab of approxi~ately 12 inches of low water cement ratio concrete. Complete record photography of the inspection is contained in CEL~-ED-DD

Me~orandu:n For Record, dated 22 December 1987, subject: ald River Low

Sill Structure, 1987 Stilling Basin Inspection. All photographs mcy be viewed at the New Orleans District. Selected photographs can be found in Appendix I.

3-02 Slab Inspection.

The three areas of the stilling basin (the north high bays, the low bays and the south high bays) exhibited various magnitudes and types of damage. As indicated by prior underwater inspections, the low bays contained the most severe damage; followed by the south high bays; with the north high bays- having sustained t.he least damage. While inspection of expansion joints for leakage was hindered due to seepage under and around the structure's gates (seals), only minor isolated leaks we~e detected, including a leak located behind Gatebay 1 which had been repaired in 1933. The leakage was occurring at the intersection of the vertical (wall) and horizontal (slab) expansion joints. After the overlay (with a new horizontal waterstop) was c~llpleted, very minor

3-1 leakage was seeping from the vertical eKpansion joint above the overlay. The only significant da~age not to be covered by the overlay was a cracked section at the downstrea~ needle seat recess in Gatebay

5. Prior to the overlay, profiles of the stilling basin slab were taken which indicated that the south side stilling basin slab had settled an average of about 2 inches with respect to the gated monolith slabs. Details and typical conditions of the slab inspection are shown on Plates 7 through 9 and Photo Nos. 1 through 9.

3-03 Plate Modules and Grout Wedge.

This inspection indicated that no loss of steel plate forns has occurred since the last inspection. The exposed grout appeared to be in very goo' condition with only minor irregularities present. Based on sampling and field investigations, a report on the durability of the fibrous grout wedge placed in September 1976 to December 1976 is presently being prepared by NOD. Details and typical conditions of the plate mod ules and grout wedges are shown on Plates 7 through 9 and Photo

Nos. 10 through 12.

3-04 Baffle Blocks.

A thorough inspection of the baffle blocks was conducted whieh confirmed previous reports which routinely mentioned eKposed reinforce~ent. The condition of the baffle blocks generally refleeted the condition of the adjacent slab, i.e., the most severely danaged baffle blocks ~ere located i~ the low bays; followed by the south ~igh bays; with the baffle blocks in the north high bays having sustai'1.:!d

3-2 the least damage. Details and typical conditions are shoW'l on P~ates 11 through 14 and Photo N:)s. 13 through 19.

3-05 Transition Walls.

The north and south walls that transition the low and high bays were also inspected. Deterioration was observed at the base of the walls with cracks being infrequently detected. Previous underwa:er patches were found to be intact and performing adequately. Detalls are sho wn in Pi:loto N:)s. 2 0 thro UJh 3 1.

3-06 stilling Basin Walls and Piers.

No significant damage to the stilling basin walls was obsecved.

The dOW'lstream face of the pier betVleen Gttebays 2 and 3 had exp:>sed reinforcane'.:. at it's intersection with the stilling basin slab. As prev iousl y mentioned, stilling basin profiles were condu:::ted. T:l.ese surveys indicated that the south stillirtg basin wall monolith hai rotated tOWlrds the backfill. At the toe, the monolith slab had settled approx.imately 2-3;9 inches with respect to the gated monoliths and 3;9 inches with respect to the adj acent stilling basin slab. At the stilling basin wall, the monolith slab had settled approx.imately 1-1/4 inches with respect to its toe. These wall movanents were first observed and reported in reference 1-03.b.(6). This report stated the top of the south stilling basin wall, adjacent to the gated monolith, had deflected toward the backfill and that this movement, which had been anticipated during constru:::tion of the wall, was evidently caused by consolidation of the underlying canpressible soils by the backfill.

3-3

This report also stated that most of the differential !D.ovenents took place during construction. Since our surveillance began on these walls, no differential movenents have been detected.

3-07 Gatebay Rail System.

On 10 May 1987, just 4 days prior to closing the lJ:)w Sill

Structure for the dewatering, a second rail failed. Unlike the first failed rail (described in Report No.8) which was a downstrea.n support

(tread) rail in Gatebay 7, this second fail ure was of an upstream guide rail in Gatebay 5. This failure did not restrict the closing of the structure. Because this failure was an alert as to possible addi:ional dama~e of the rail systems, the high bay support rail systems were inspected. Results are con linei in Appendix IV.

3-08 Upstream Needle Seat Recesses.

Since results of the gatebay rail system inspection referenced above indicated tha t repairs were necessary, an inspec tion was coo.d u:: ted of the high bay upstream needle seat recesses to assess the adequa:y of the seats to support a closure system. Results are contained in

Appendix V.

3-09 Comparisons.

The result s of this stilling basin inspection were conpared to previous underwater inspections. In general, the results of this inspection confirmed both the magnitude and type of dan~e previously reported wi th only minor differences in the precise locations of some of

. the damagel areas.

3-4

SECTION 4 - REPAIRS

4-01 General.

Prev ious repairs to the Iow Sill stilling basin have ahays been perfonned under\<Witer. '!he construction of a downstream sand closure

(see Plate 17) and the installation of a de\<Witering system (see Plate

18), made possible the first de\<Witering of the stilling basin shce it was constru:::ted almost three decades ago. Concurrent with the de\<Witering, rail repair closures (see Plate 15) were installed to facilitate gate rail rehabilitation by providing the dryenvironnent necessary to efficiently repair the damaged rail systems. All repairs not included in the de\<Witering contract were prioritized and executed in order of severity, proceedin~ with the most severe damage being repaired first.

4-02 S lab Repairs.

The primary purpose of the de\<Witering proj ect was to overlay the majority of the stilling basin slab with approximately 12 inches of low

W!ter cement ratio. See Plate 10 for details. The entire overlay was successfully completed. In addition to the overlay, a repair of the cracked section at the downstream needle seat recess in Gatebay 5 was perfonned by jackhammering out the affected concrete, installing #6 dowels and placing low water cement ratio concrete.

4-03 P late Modules and Grout Wedges.

Protrooing portions of plate modules were cut flush with be surface. Surface gouges and spalls in the grout were repaired by shotcreting. This shotcreting was performed in the vicinity of the remnant of Plate M:>d ule 23 and in other randcm areas. '!he north and

4-1 south high bay grout wedges were extended approximately 14 inches making th em flush with the vertical transition walls. See Photo NJ. 1 2.

4-04 Baffle Blocks.

Since most of the baffle block damage was covered by the slab repairs (OITerlay) , only minimal damage remained. This remaining damage was repaired by shotcreting. '!he purpose of this repair method io1aS to cover exposed reinforcement and restore baffle block geometry. Baffle blocks which \¥ere repaired by shotcreting are SOOTNn on plates 11 throU]h

14. See :Rloto NJ. 18 for resul ts.

4-05 T ransi tion Walls.

The deterioration at the base of the transition walls was covered by the overlay as \¥ell. '!he only repairs perforr ,d were the restoration of the two patches placed on the south transition wall during the 1980 and 1985 inspections. This rehabilitation was also performed by shotcreting and resulted in a more uniform surface with fewar surface irregularities and protrusions. See Photo N:>s. 29 and 31.

4-06 Stilling Basin Walls and Piers.

'!he exposed reinforcenent on the doTNnstream face of the pier bet\¥een Gi tebays 2 and 3 was repaired by shotcreting. Most of the insignificant damage to the stilling basin walls was covered by the overlay.

4-07 Rail Repairs.

A part of the original contract, the support or tread rail systems in Gltebays 5, 6 and 7 were rehabilitated through the use of the rail repair closures. See Plate 15. As a result of the operation e:q:erience

4-2 described in 3-07, the guide rail systems in these same 3 gatebays were repaired. See plate 16 for limits and details. Based on the results of the inspection presented in Appendix IV, the high bay guide and tread rail systans were also repaired. See Plate 16. Since the condition of the high bays was not as bad as the low bays, the repair method vas not as elaborate. Hbwever, in order to expedite high bay repairs, an additional closure was fabricated. This additional closure consisted of a duplicate set of needles, a duplicate upper safety strut system and a modification to one of the existing needle beams originally fabr~cated with the structure. Half round cofferdams were not necessary since the water imp:nlI1ded by the structure and the sand closure was mainta~ned below the sill at El.. 10. o.

4-08 upstream Needle seat Recesses.

No repairs were made to the high bay needle seat recesses ~o facilitate the use of rail repair closures. Instead, timber blo:::king was used to span deficient areas.

4-09 Materials U sed I n Repairs.

a. Concrete For Stilling Basin Overlay.

(1) Design: ComI%'essive strength water Canent Ratio

(2) Contractor Mix Proportions:

= 5,000 psi < 0.45

Material Weight vater Canent Sand Chert (Aggregate) Water :Redu:::ing Aimixture Air Entrairment Adnixture

4-3 lbs lbs lbs lbs oz oz

Since the contractor experienced difficulty in pumping concrete for the first tYlO stilling basin overlay p::>urs, the following mu was used on the remainder of the overlay.

Material

Witer Cement sand Chert (Aggregate) Water Redu::ing Mmixture Air Ehtrainnent Admixture

b. Grout For Rail Repairs.

Weight

220 lbs 658 lbs

1198 lbs 1774 lbs

41 oz 10 oz

(1) Design: Canpressive strength = 5,000 psi

(2) Contractor Mix Prop::>rtions:

Material

Witer Cement sand water Reducing Admixture Al un inurn POwler

c. Grout Under Needle Support Plate •

Weight

448 lbs 846 lbs

2527 lbs

84.5 oz 31 g

(1) Design: Compressive strength = 5,000 psi

(2 ) Contractor Mix Proportions:

Material water Cement Al uninum R>wder

Weight

45.9 lbs 94 lbs

1.5 g

d. Shotcrete For Baffle B lock and Miscellaneous Repairs.

Material: Sikatop 124 (p::>lymer-cementitious 2-canp::>nent mortar with aggregate) manufactured by Sika Corporation.

e. Epoxy For Needle Support plate Anchor Bolts.

M:lterial: Hilti HVA vinylester resin adhesive capsules manufactured by Hilti Fastening SystEmS, Inc.

f. Epoxy For Stilling Basin Concrete Overlay Dowels.

Material: Kelipox y (epoxy-grout) manufactured by Kel ken-G:lld, Inc.

4-4

SECTION - 5 CONCLUSIONS

5-01 General •

Based on the information gained in this effort and the repairs effected, it is concluded that:

a. The low sill Stru::::ture is sound, and fully capable, with appropriate future maintenance, of performing its intended functions in concert with the Auxiliary Stru::::ture.

b. The underwater inspection routine utilized in the past is an efficient and cost effective means for monitoring the condition of the low Sill Structure. Since the existence of the Auxiliary structure will permit complete closure of the low Sill Structure for inspection I the difficulty and cost for such inspection will be redu::::ed.

c. The post-repair condition of the low Sill Stru::::ture is such that some reduction in surveillance effort is warranted.

5-02 Foundation.

Piezometer installation confirmed the extent of the 1973 (:lood) scour damage to the stilling basin drainage blanket and the subsequent grout repairs. Based on piezometric data obtained during and apart from the de~tering, the stilling basin drainage blanket is functioning properly, except for the area damaged during the flood of 1973. With the addition of tw:> more stilling basin piemmeters (RPB-11 and RPB-14), an accurate representation of uplift pressures will be obtained from the permanent pie mmetric instrunentation.

5-03 Existing Conditions.

The final task of the de~tering contractor was the removal of the dewatering system and sand closure, except for all portions belo'", El. 5.0, including the collector 'pipes, a portion of their verti:al

5-1 risers, a portion of the rock dike and the base of the sand closure.

Certain features of the rail repair closures were also abandoned in place, including all anchor bolts installed underW3.ter, the needle support plates (located in the needle seat recesses of the 3 low bays) and the grout between the needle support plates and the eroded concrete surface. The needle support brackets, however, were retrieved. A; of this report date, none of the above rennants have hindered the ope:oation of the structure or the canplex since being abandoned, nor is it anticipated that they will be the cause of any problem in the future.

See Plate 20 for existing outflow channel conditions (contours).

5-2

APPENDIX I

Rlotographs

Photo No.1. General View of Stilling Basin. Note Three Overlay Strips on North High Bay Slab.

photo No.2. General View Of North High Bays.

I-I

Photo No.3. General View of South High Bays.

Photo No.4. Looking Southeast at Underwater Grout Patch on Slope Behind Gatebay 1. 'rypical for Patches Placed Underwater.

1-2

Photo No.5. Looking ll'streatn (East) at Center of Gitebay 5 OO..,-,stream Needle Seat . Note Grout Patch And crack In Seat.

Photo No.6. Looking tvrthwest at J.nw Bay Slab Between First and Second lbwof Baffle Blocks . Note Baffle Block tv: 29 ('lbp Left).

1-3

Photo No.7. Looking Northeast at Damage Behind Gatebay 8. "ate Missing Reinforcenent .

Photo No.8. Looking Upstream (East) at Undercut (Crack) in Slab Behind Gatebay 9.

1-4 t~:: :--.

Photo No . 9 . ~noking South at South lIigh !lay Slab 4 ) stream (Eastl of First lbw of Baf fle BLocks .

1-5

Photo No. 10. Looking N.Htheast at I-brth nigh Bay Grout Hedge and Plate ~kJd ule Ronnants.

Photo No. 11 . Typical Spall in Qcout HeLlge Near End Sill and IJehhrl IJaffle Dlock No. 12. Note Condition of Gmut.

I-{:;

\ .... ~ 'I: . f

Photo No . 12. Looking D)wlstreCltn (t'cnt) at Grout Wedge on N::>rth nigh B'lys. t-btc Area of lb Grout Placenent and JDw Bays to Left. Area

Co ncreted D.lring OJerlay .

1-7

Photo No. 13 . Downstream (;;cst ) f'ilC" of Baffle Block No. 3 .

Re info cceme nt T}'pical for High Bay Daffle Blocks .

4. t,.... , . .. ~

.... . 1 · , .. ~ " . ~' . .. , .. '.~""" _; . " f:xposed

Pho t o Uo. 14.

Spa ll , No rthwes t Co rnt"r o ( Ua ffle ntock No.5 . Typical Hiner

1 - 8

Photo No. 15. Downstrea'n (Hest) and tbrth Face of Baffle Block tlo. 24.

Typical of In .. Day Baffle Block.

Photo No. 1&. Upstream (Ea!3t) itnd South Face of Baffle Block No. 25.

Ho te E'<posed Hein(orceme'lt on Upstream Face.

1-9

Photo No. 17. Southeast Corner of Baffle Block No. 38. Most Severely Dallagcd Baf fle Block.

Photo No. 18. Shotcrete R"pai.r to Southeast Corner of Baf.fle Block

tv. 38 Danage ~lO wn in ~\oto lb. 17.

1-10

Photo 110 . 19 . Northc.,st CQrner o f Ba[[le Block No. ~9 Showing 1Y?ical E>::posed O:nner Reinforcenent.

Photo No . 20. making (no rth) at f'hrth Tr.ansitiQn Nall at lnters~ction of Slop~tl and flori zontal Portions of II igh &!y Slab. Note Vertical O''lck .1t Right Do ttom.

1-11

Photo tlo. 2 1 . J..noking (Uor-th) at NJrth Tr;JnsitiOIl Hal l ~ar. Ex paris ion Joint Oet",,""'en Stilling Bi1sin f.1ono l iths (l.J3ft) a nd Gated '·lonQliths (Right). N0te Crack at Top of li.11.

t- 12

Photo No. 22. Looking (North) at North Transition ~Iall Upstream (East) of First lOw of Baffle Blocks.

photo No. 23. Lookin." (North) at North Transition Wall at First Row of Oa (fle Blocks.

r-13 photo No. 24. Looking (North) at North Transition viall Between First and Second Ibw of Baf fle Blocks.

Photo No. 25. Looking (North) at North Transition Viall Downstream (\'/es t) of Second Ibw of Baf fle Blocks.

1-14

...;4." ....... " . . ' . ~ .

Photo No. 26. Looking (North) at North Transition Hall at End Sill \'bll. !lo te Spall at End Sill ('lbp Left). Spall Repaired by fhotcreting.

Photo No.2 7. loo king Southeast at South Transition Wall. Note Underwater Goout Ritch ():)"'lstreaIR (East) of Expansion .J:>int Bet .... en Gated M:>noliths (Left) and Stilling Basin M:>noliths (Right).

1-15

Photo No. 28 From Nall.

Grout I'l tch Sho\01 in Ihoto NJ. 27. Note Rl t c ll Procrooing

_ ~ 4. ~_~

~~ ~~~ .. r .. :;:-: ~ 1".os ..

Photo No. 29. Grout Fatch Sho\01 in Ihoto NJ. 28 Repaired by Shotcreting. Note NJ IIbrupt Surfaces.

1-16

Photo No. 30. L'lokln3 Southwest at South Tr'lllsltlon l1alt .3t E"d SLt.

Note U"Jerw,tter Grout Patch.

Photo No. 31. Grout Patch Sho,,,, h ~loto tb. 30 Repaired by Shotcret lnJ.

1-17

Photo No. 32. General View of Slab Jepairs (Overlay).

Photo No.3 3. IDoking D:>wn at Pail Jepair Closure Needle Beam (Top). Needle Supports and Brackets (Qmter). and !bif Round Cofferdam (Left). N:lte '11,at Brackets Were Petrieved and Needle SUpport Was Left.

1-18

Pho to No . 34. Failed (Upstream) Guide Rail in lbrthside of Glteba y 5.

1-19

Photo No . 35 . Failed (Do,""streatn) Tread !bil in IDrthside of Gatebay 7. IDte ~'lat Clips are !Dose and lower Hardware is Hissir.g.

1-20

Photo No. 36. Failed Dld of 'fread !ail SloWf\ in Illoto lb. 35.

Photo No.3 7. He" Tread RotH System Prior to o>ncreting. Note '1lHt Reinforcement is Not ShOWl.

1-21

Photo No. 38 • . Completed Rlil System rupairs.

1-22

APPENDIX II

Discharge Diversion Ratio Curves Auxilary Structure

-J

~ 40 l-

LL

LLJ

C) 30

RATIO NO.2 RATIO NO. I

O~----~----~----~----~ ____ ~ ____ ~ ____ -J o 70

NOTE: STAGE IS AT KNOX LANDING.

DISCHARGE DIVERSION RATIO Cl:RVES

AUXILIARY STRUCTURE

APPENDIX III

Narrative Ccrnpletion Report en Contract No. DACW29-87-C-0124

And Memorand un Thereto

DmSPOSITaON .... ORM Fo- Ute .f this form, _ A'" 3.0,'5; the proPonent ec.ncy it TAGO, "'EFE"'ENCE 0'" OFFICE SYMBOL SUBJECT

Narrative Completion Report for Contract DACWZ9-87-C-0124, Old

LMNLA

River Control, Low Sill Control Structure, De'o1atering, Stilling Basin And Rail Repairs, Concordia Parish, Louisiana

TO: CIConst Div ATTN: Cont Admn Br

FROM: Asst. Project EngineeDATE II uct 01

Mr. Legenire eMT 1

1. The contract was awarded to Al Johnson Construction Co. & Massman Construction Co., A Joint Venture, on 8 May 1987 for the amount of $4,821,000.00.

2. Work under this contract consisted of constructing a hydraulic placed sand closure, installing and operating a dewate'ring system, installing fabricated steel closures, repairing damaged gate rails in 3 ~atebays, placing a 12 inch thick concrete overlay on the entire stilling basin surfac~, the removal of the fabricated closures, the stone retaining dike, and the hydraulically placed sand closure.

3. The Prime Contractors, Al Johnson Construction Co. and Massman Constnction Co. are from Minneapolis, Minnesota and Kansas City, Missouri, respectively. The subcontractors, and their areas of responsibility, are as follows:

Pensacola Construction ~o.

Kansas City Missouri

Pine Bluff Sand & Gravel Co.

Pine Bluff, Arkansas

Boyles Brothers Drilling Co., Inc.

Salt Lake City, Utah

Acadiana Divers & Salvage Corp.

Lafayette, Louisiana

Moretrench American Corporation Tomball, Texas

A & B Concrete Coring Company Baton Rouge, Louisiana

Oliver Company of Louisiana, Inc.

Baton Rouge, Louisiana

Furnish and install collector pipes, stone retaining dike, gravel cover and filter fabric. Remove rock dike and risers on collector pipes.

_ Construct sand bedding for filter cloth.

Construct and remove sand closure dike.

Supervise drilling for needle support anchors.

Assist in drilling and install needle support anchors. Assist in installation and removal of rail repair closures.

Furnish and install wellp~int dewatering system.

Saw cutting of concrete a~d drilling of holes in concrete for steel reinforcement dowels.

Shotcreting baffle blocks.

4. The first notice to proceed was i.sued and acknowledged by the contractor on 13 May 87, the day of the preconstruction conference. This contract required the co~tractor to prepare and execute all submittals, especially those concerning the rail repair closures, within three (3) days after acknowledging the first notice to proceed. He was also required to obtain all needed materials for the rail repair closures, alo~g with the collector pipe, stone, gravel and filter cloth, and deliver them to the w~rk site. The minimum time between issuance of the first and second notice to proceed could not be less than fourteen (14) calendar days.

"I'IEVIOUS EDITIONS WILL BE USED

• uSG~O '966-1.90-003/.3241

U1NLA

SUBJECT:

Narrative Completion Report for Contract DACW29-87-C-0124, Old River Control, Low Sill Control Structure, Dewatering, Stilling BaEin And Rail Repairs, Concordia Parish, Louisiana

5. The Government closed all of the Low Sill gates on 14 May 87. Thi! allowed the Mobile District of the Corps of Engineers to begin installing piezometers in the stilling basin downstream of the structure. Between 16 May 87 snd 30 May 87, eighteen (18) piezometers were installed under the directio~ of New Orleans District Geologists.

6. The second notice to proceed, issued on 29 May 87, directed the cor.tractor to begin work on 1 June 87 and to complete the entire contract. requirentents within one hundred forty (140) calendar days. This set the date for completion to be 18 October 87."

7. The prime contractor began work on 1 June 87 by mobilizing equipmer.t and barges to the site to start the rail repair closures. A summary of actual con struction activities follow.

A. Stone Dike Pensacola Construction Co. arrived with a spud barge and rock barges containing "c" stone on 2 iune 87. The dike was constructed in three (3) sections and each section was built in three (3) phases. Phase one was a bedding placed on the channel bottom to give a flat surface for the collector pipe. Phase two was the anchoring of the collector pipe with stone to keep jt from rotating once it was placed on the bedding. Phase three was the building of the dike to final grade. The center portion of the dike was constructed between 3 June 87 and 20 June 87. The south section was placed between 6 June 87 and 19 June 87. The north section was built between 9 June 87 and 18 June 87.

B. Gravel Cover A twenty-four (24) inch crushed stone cover ,..as placed on the downstream face of the rock dike to fill in the voids between the "c" stone and to keep sand from washing through the dike and depositing on the stilling basin floor. Crushed stone was stcck piled on the upstream side of the dike to be placed on the upstream face at a later date after dewatering was underway. This operaticn was performed from 21 June 87 to 24 June 87.

C. Collector Pipes These pipes were twenty-four (24) inches in diameter with one (1) inch thick walls, and a fourty~two (42) inch vertical riser pipe with one-half (~) inch thick walls, near each end. The bottom one hundred eighty (180) degrees had one and a half (l~) inch diameter holes to allow ~ater to enter the pipe and be pumped out. The purpose of these pipes was a secondary line of interception for seepage from the tailwater through the dike. The wellpoints were the first line of interception. The north and so~th

-2-

LMNLA

SUBJECT: Narrative Completion Report for Contract DACW29-87-C-0124. Old River

Control. Low Sill Control Structure. Dewatering. Stilling Basin And Rail Repairs. Concordia Parish. Louisiana units were approximately two hundred thirty (230) feet long and the middle unit was approximately one hundred fifty (150) feet long. Tbe north end of the middle unit had to be raised six and one half (6~) feet above horizontal to allow the pipe to fit the contour of the channel bottom because of derrick stone placed during a previous time. The middle unit was installed on 5 June 87 and was inspected by Government contract divers on 6 "June 87. The south unit was installed on 9 June 87 and inspected immediately after the pipe was lowered onto the rock bedding. The north unit was also inspected immediately after placement on its rock bedding on 12 June 87.

D. Sand Closure The dredge "Marion". belonging to Pine Bluff Sand & Gravel. arrived the afternoon of 20 June 87 and started pumping the sand bedding for the filter fabric on the north bank on 22 June 87. The dredge pumped material until 24 June 87 but could not get the material any higher than elevation +17.0. The design elevation for the top of the bedding was +27.0. On 24 and: ) June 87 the dredge pumped on the south bank but achieved the same Legative results. The dredge could not deposit the material at the desired elevation because the water in the outflow channel was only at elevation +16.1 on 22 June 87 and had dropped to +14.3 by 25 June 87. The long range prediction indicated the water in the outflow channel would drop even more in the near future. The Government agreed that the material could not be hydraulically placed and directed the contractor to place the material by any method he deemed practical. but only up to a modified elevation of +20.0

Two (2) barge mounted draglines and land based equipment were used to finish grading the material for the filter fabric bedding on the north and south banks. The north bank operation began on 25 June 87 and was completed on 27 June 87. The south bank was begun on 25 June 87 and was completed on 30 June 87.

Due to the low ~ater stages and the predicted future lower stages.

the sand closure was reduced in cross sectional area with a new crown elevation of +20.0 and shifted closer to the st~ucture. The dredge began building the sand closure on 25 June 87 and completed all work on 8 July 87. Land based equipment worked until 10 July 87.

After the sand dike was brought to grade the prime contractor used crushed asphalt to build a haul road on the crown. This road was ~onnected on the north and south end to ramps that had been built down the slope of the banks to the outflow channel.

-3-

SUBJECT, Narrative Completion Report for Contract DACW29-81-C-0124, Old River

Control, Low Sill Control Structure, Dewatering, Stilling Basin And Rail Repairs. Concordia Parish, Louisiana

E. Filter Fabric The filter fabric was placed on the north and south banks of the outflow channel starting at the end of the wing .all and extending downstream approximately three hundred twenty (320) feet.

The fabric was rolled down from the upper limits of the bank down t) the waters edge where it was placed on a barge. The barge was moved to.ard the center of the channel as the fabric was unrolled, wet down. with water, weighted down with sand bags, and ·sunk into position down the slope of the bank underwater. The fabric was placed in sections of forty-five (~5) feet by two hundred ten (210) feet and overlapped ten (10) feet at aplices.

The area covered 'by the fabric was approximately sixty-four thousan:i (64,OCO) square feet. The north bank was placed on 28 June 81 and the south bank on 30 June 81.

F. Dewatering System The dewatering operation was started on 9 July 81 with the installation of a ten (10) inch discharge line run on top of the north wing wall and over gate no. 1. On 10 July 81 a ten (10) inch Flygt submersible pump was installed in the north riser of Unit I, attached to the discharge line over gate no. 1, and started pumping water from the impounded area.

A ten (10) inch discharge line was run over the south wing wall and connected to a ten (10) inch Flygt submersible pump in the south riser of Unit III. Two more Flygt ten (10) inch pumps were placed in the north and south risers of Unit II. In manholes 5N and 5S two (2") Gorman Rupp submersible pumps were placed and in the impounded area two (2) eight (8) inch Gorman Rupp submersible pumps were mounted on floating platforms.

Three barges were placed end to end in the center of the outflow channel on the downstream side of the sand dike. Half of the first barge was on the slope of the dike. The discharge lines for the pumps were laid across the dike and all converged at the barges. The lines then went out on the barges to discharge in the outflow channel well downstream of the closure.

G. Wellpoint System The wellpoint system. was the primary line of interception for seepage from the tailwater through the sand closure.

The wellpoint system was started on 21 July 81 and put into operation on 21 July 87. The system consisted of an eight (8) inch header pipe laid parallel to the crown of the dike and set at elevation +14.0.

The wellpoints were two (2) inch PVC pipe twenty-two (22) feet long with the tip elevation set as low as they could be installed.

Becker six (6) inch vacuum pumps were used to operate the system.

Three (3) pumps were placed in center of the system and one each was placed near the ends of the header pipe at the north and south wing wall.

-4-

SUBJECT: Narrative Completion Report for Contract DACW29-S7-C-0124, Old River

Control, Low Sill Control Structure, Dewatering. Stilling Basin And Rail Repairs, Concordia Parish, Louisiana

H. Fabrication of Rail Repair Closures The contractor had some parts of the closures fabricated in San Antonio. Texas and part in New Johnsonville, Tennessee. The needles were fabricated from Z-27 sheet pile supplied by the Government. The "J" type seals that were used on the north and south needles along with the "L" type seals that were used on the bottom of all needles and on the half round cofferdams were also supplied by the Government.

A needle was fabricated from two (2) sheets of Z-27 sheet pile and ten stiffener plates. The north needle had a plate welded to the female interlock and strapped to its face running down the length of the needle. The south needle was a box beam fabricated of steel plate and the female interlock of a Z-27 sheet pile.

There were three (3) sets of closures fabricated for the low bays, gates 5, 6, and 7. One closure consisted of; a needle support that was bolted into the slab of the structure and six (6) needle support brackets that bolted to the needle support; one (1) north needle, one (1) south needle and thirteen (13) center needles; a needle beam and two (2) needle beam supports; a north and a south half round cofferdam; two (2) beam safety supports; and an upper safety strut.

The contractor submitted an alternate design to the upper safety s:rut in the contract and was willing to give the Government a credit if it was acceptable. This strut would mount to the river side of the pier and could be put in place without removing the gate. In the Governments design the strut mounted between the piers and could not be erected until the gate was removed. The Government reviewed the submittal design and approved its use for the rail repairs.

I. Installation of Rail Repair Closures The first step in the installation of the rail repair closures was the setting of the needle support in the needle seat of the gatebay slab. A drilling templa~e was attached to the needle support before it was lowered into posi~ion.

A drilling platform was mounted between the piers of the low bay gates for the drillers to work from. The drills were attached to the platform and the drill casing lowered to the template where a diver would insert the casing into a riser on the template. The diver would then lea'1e the water and the drillers would core through the concrete to a de~th of approximately eighteen (IS) inches.