SIERRA MADRE RESERVOIR RAHABILITATION PLAN NO. 1178

ADDENDUM #1

SIERRA MADRE RESERVOIR RAHABILITATION

PLAN NO. 1178

Date of Addendum No. 1: October 25, 2016

Addendum No. 1 Page 1 of 2

City of Glendora Addendum No. 1

Sierra Madre Reservoir Rehabilitation Plan No. 1178

October 25, 2016

The Bidder shall execute the certification on page 2 of 2 of this addendum and shall submit the signed certification with Bidder’s Proposal.

I. Modifications to Bid Opening Date: A. Extend Bid Opening Date two (2) additional weeks. B. Bid Opening Date is scheduled for November 10, 2016 at 10:00 a.m.

II. Modifications to Technical Specifications:

A. Revise Section 03314 – Prestressed Concrete Tank.

End of Addendum No. 1

Addendum No. 1 Page 2 of 2

City of Glendora 116 E Foothill Blvd Glendora, CA 91741 Addendum No. 1 October 25, 2016 Prepared by: City of Glendora BIDDER'S CERTIFICATION I acknowledge receipt of the foregoing Addendum No. 1 and accept all conditions contained herein. Dated: ___________________________ Company: ___________________________ Bidder: ___________________________ Title: ___________________________ Signature: __________________________

THIS FORM MUST BE COMPLETED AND SUBMITTED WITH BID

Sierra Madre Reservoir Rehabilitation PRESTRESSED CONCRETE TANK City of Glendora 05/2016 03314-1

SECTION 03314

PRESTRESSED CONCRETE TANK

PART 1: GENERAL

1.01 SCOPE OF WORK

A. This section covers the complete furnishing and installation of seven-wire strand and

bars for circumferential and vertical prestressing, respectively, of concrete walls,

special forming requirements and the complete shotcrete application operation. This section also covers the qualifications for the CONTRACTOR (i.e. GENERAL

CONTRACTOR), Prestressing contractor, and Shotcrete contractors. This section also

covers general requirements for the tank and construction materials used in the tank. If

a discrepancy between this section of the Specifications and any other section of the Specifications occurs, this section shall govern. The words "stressing machine" may

refer to either circumferential wrapping machinery or vertical tendon stressing

equipment.

B. The CONTRACTOR shall furnish and construct the circumferential prestressing and

shotcrete application for the existing concrete reservoir as shown on the Drawings.

C. Concrete work shall conform to the provisions of Section 03300, "Cast-in-Place

Concrete", as supplemented and modified by this section.

1.02 RELATED SECTIONS

Section 03100 Concrete Formwork

Section 03200 Reinforcing Steel

Section 03230 Earthquake Cables

Section 03251 Expansion and Construction Joints

Section 03255 Tank Wall Base and Top Joint

Section 03300 Cast-in-Place Concrete

1.03 REFERENCES

ACI 306R Cold Weather Concreting

ACI 506.3R Guide to Certification of Shotcrete Nozzlemen

ASTM A416 Specification for Uncoated Seven-Wire Stress-Relieved Steel Strand for

Prestressed Concrete

ASTM A722 Specification for Uncoated High-Strength Steel Bar for Prestressing

Concrete


AWWA C651 Disinfecting Water Mains

AWWA C652 Disinfection of Water-Storage Facilities

ICRI Concrete Repair Manual

1.04 EXPERIENCE OF GENERAL CONTRACTOR (BIDDER), PRESTRESSING

SUBCONTRACTOR (PRESTRESSOR) AND SUPERINTENDENT

A. Due to the nature of the project, it is the intent of these Specifications to obtain a first

class product with emphasis on overall safety, quality and quality control, both during and after the construction process. Only GENERAL CONTRACTORS and

PRESTRESSING SUBCONTRACTORS experienced in the construction of wrapped

strand prestressed concrete tanks are qualified to bid on and rehabilitate this tank project.

B. The PRESTRESSING SUBCONTRACTOR shall be a specialist contractor

experienced in the prestressing of AWWA D-110 Type I tanks, having prestressed, in

their own name, at least 10 tanks in the last 10 years, which have been in successful service for a minimum of five (5) years, meeting the specified criteria listed herein. All

PRESTRESSING SUBCONTRACTORS are required to be qualified. The bidder

(GENERAL CONTRACTOR) is required to state on the face of his sealed proposal, the name of the qualified tank PRESTRESSING SUBCONTRACTOR.

C. The GENEARL CONTRACTOR (Bidder) shall have been the General Contractor

and/or the Tank Subcontractor on at least two (2) AWWA D110 Type I tanks of either new construction or rehabilitation within the last ten (10) years. The Engineer will

review the qualification package along with the bid package to determine which

contractors meet the requirements.

1.05 WORK BY PRESTRESSOR

A. No stressing system falling under any of the following requirements will be considered

unless it has been successfully used on tanks of at least one-half of the diameter, height

and capacity. The GENERAL CONTRACTOR shall submit with his bid the name and location of the CITY and the completion dates of ten (10) tanks on which the proposed

qualifying "stressing machine" and automated shotcrete equipment has been used by

the PRESTRESSING SUBCONTRACTOR within the past ten (10) years. All tanks

listed for the Prestressor's experience requirements must have been prestressed in the Prestressor's own name. Experience of personnel associated with the Prestressor or

hired by the Prestressor will not be considered unless the Prestressor can demonstrate

that the work was contracted and performed directly by the listed Prestressor in its business name.

B. Descriptive literature shall also be submitted with the bid showing the proposed

machinery with the recorders and a typical copy of an actual recording of the applied forces taken from one of the jobs on which such machinery has been used. Any

stressing system that will not provide the substantial equivalent of the above require-

ments will be rejected


C. A bid may not be considered responsive unless such data has been submitted with the

bid. This applies to the wrapped strand, tendon-stressing and automated shotcrete equipment.

D. Experience gained by the Prestressor in machine single wire wrapping, internal tendon

systems or external tendon systems will not be considered in meeting the required

experience requirements.

E. If subcontracted, the prestressing firm or individual(s) will be responsible to the

GENERAL CONTRACTOR for the following phases of work:

1. Furnish, stress and pressure grout the vertical prestressing tendons with epoxy.

2. Abrasive blast the exterior concrete core wall and apply shotcrete scratch coat.

3. Furnish and install the horizontal prestressing strand.

4. Apply the shotcrete covercoat over the wrapped strand.

1.06 BID SUBMITTAL REQUIRED BY CONTRACTOR

The following information shall be required to be submitted with the CONTRACTOR's bid

submittal:

A. General contractors shall submit one copy of a qualification submittal along with the sealed bid package on the advertised bid date. The general contractors shall submit a

complete record of their experience in the new construction or rehabilitation of

prestressed concrete tanks conforming to AWWA D110, Type I as indicated in section 1.4, along with their Prestressing Subcontractor qualification. The record shall indicate

the size of the tank, the name and address of the OWNER, the year of completion or

rehabilitation, and the name of the ENGINEER for each project. Experience in the construction or rehabilitation of AWWA D110 Type II or III tanks is not acceptable.

Provide the names, project responsibilities, experience on similar projects and resumes

for personnel responsible for the following: Project Manager, Site Superintendent, and

Quality Control Manager.

B. Construction Equipment, Materials and Methods – Provide the following:

Summary of all equipment to be used in the rehabilitation of the tank.

Construction schedule and plan including labor requirements and

responsibilities, sequencing, materials and methods.

Quality control plan and procedures including testing, correcting

deficiencies, systems and methods, schedule and responsibilities.

List all major suppliers and subcontractors who may work on this project.

C. Financial Capacity – Provide the following:

References for bank and bonding company

Insurance Limits

Warranty Statement


D. The contractor shall sign and date the information provided and certify that to the extent of the Contractor’s knowledge, the information is true and accurate, and the

design and construction supervisory personnel for the tank construction will be directly

involved with and used on this project. Substitutions of personnel and/or methods will

not be allowed without the written authorization of the Owner. A bid may not be considered responsive unless the GENERAL CONTRACTOR's, and associated

superintendent's, experience requirements have been submitted with the bid.

1.07 CONTRACT AWARD

The Contract will be awarded on the basis of the methods, material and equipment shown on

the Drawings and specified in these Specifications. The Specifications and Drawings are

based on proven construction techniques that result in successful low-maintenance tank water storage performance. The following specific design criteria and salient characteristics are

considered essential to the successful construction of the specified prestressed concrete tank.

A. Experience in constructing a large quantity of successful tanks, ease of construction,

CONTRACTOR familiarity with this type of tank construction and reduced inspection costs associated therewith.

B. External, continuously wrapped strand circumferential prestressing providing the

desired bond with the shotcrete in addition to the final force specified. (No stressing system based on single wire wrapping, pulling wire through a die or jack-operated,

circumferential tendon or cable systems, based on circumferential movement of the

wrapped wire prestressing steel after it is placed in/around the wall, will be allowed.)

C. Positive anchoring system of circumferential wrapped strand prestressing to the

corewall and spaced as shown on the Drawings.

D. Maximum allowable spacing of circumferential wrapped prestressing strands as shown

on the Drawings.

E. Galvanized circumferential wrapped prestressing strands for long-life performance.

F. Continuous and instantaneous recording and correction of all applied prestressing

forces.

G. A maximum acceptable stress tolerance of +1.5% at any point along the prestressing

steel.

H. No variation in prestressing forces due to friction losses.

I. Automated, wet-mix 10-sack shotcrete applied over a fully abrasively blasted concrete corewall.

J. External paint protection as specified here-in.


1.08 NON-RESPONSIVE BID

The information required in Section 03314.01.06 above shall be submitted with the bid

proposal. Failure to submit such information may be deemed a material irregularity which

may cause the bid to be rejected as non-responsive.

1.09 SUBMITTALS FOR REVIEW

A. Section 01300 - Submittals: Procedures for Submittals.

B. CONTRACTOR shall submit circumferential wrapped strand prestressing wrapping

schedule and the intermediate lock-off elevations for the ENGINEER's review and approval before the wall pour is made.

C. CONTRACTOR shall submit shop drawings of the method of anchoring and splicing

of the circumferential wrapped prestressing strands.

D. The CONTRACTOR shall submit mill certifications for the seven-wire strand and

high-strength threaded bars to verify conformance with these specifications.

E. Shotcrete mix design prepared by the supplier and signed material submittal certifying the proposed mix design meets the requirements of these specifications.

F. Nozzle man certification in conformance with requirements of Section 03314.3.12.D if

hand placed shotcrete is to be applied.

1.10 SUBMITTALS FOR INFORMATION

A. Section 01300 - Submittals: Procedures for Submittals.

B. CONTRACTOR shall submit the prestressing force recording tapes for both the

circumferential and vertical prestressing. These shall become the property of the OWNER.

1.11 QUALITY ASSURANCE

A. Testing of Prestressing Material

1. Prestressing CONTRACTOR shall furnish, at his own expense, Mill test certificates showing the dimensional and physical characteristics of each size,

heat or reel of the prestressing steel he has furnished. Additional tests by a local

testing laboratory and at CONTRACTOR's expense will be required for incomplete certificates and prestressing steel of foreign origin.

2. Prestressing CONTRACTOR shall furnish evidence, to the satisfaction of the

ENGINEER, prior to the preparation of shop drawings and installation of vertical threadbar, that the proposed threadbar tendon anchorage system meets the

requirements of these specifications. The ENGINEER may order additional tests

to be taken. Should such additional tests not meet the specifications, the


CONTRACTOR shall be responsible for the expense of these tests; otherwise

such expenses shall be borne by the CITY.

B. Calibration/Accuracy of Prestressing Equipment

1. Before any stressing operation may be started, CONTRACTOR shall calibrate all

recording equipment at an approved testing laboratory to the satisfaction of the

ENGINEER.

2. All continuous force readings for either the vertical or the circumferential

prestressing operations shall be developed with electronic (or the substantial

equivalent) force (strain gauge method) sensing transducers, all having a maximum non-linearity error of +0.5% and a maximum hysteresis error of

+0.25%.

1.12 GUARANTEE

A. The CONTRACTOR shall guarantee the work against defective materials or workmanship for a period of one (1) year from the date of completion. If any materials

or workmanship prove to be defective within one (1) year, they shall be replaced or

repaired by the CONTRACTOR at the CONTRACTOR’s expense.

1.13 PRODUCT DELIVERY, STORAGE AND HANDLING

A. Prestressing steel shall be adequately packaged to protect against intrusion of chemical

contaminants (from the atmosphere or otherwise) for the protection of the steel against physical damage and corrosion during (and subsequently as the result of) shipping and

storage.

B. Prestressing steel that has sustained physical damage through rust or otherwise will be

rejected.

C. All materials and prestressing material delivered to the job site shall be stored off the

ground on planks, supported by 4" x 4" timber, which must be covered with

polyethylene or sizalkraft paper to prevent any moisture from coming up from the bottom.

D. Reels of strand, prestressing tendons, anchors, etc., shall be stacked neatly and as

compact as possible.

E. All materials for tendons and all fabricated tendons shall be covered with tarpaulins in such a manner that water, rain, moisture and dust are kept away.


PART 2: PRODUCTS

2.01 SEVEN-WIRE STRAND

A. Hot-dipped galvanized seven-wire strand used for circumferential wrapped strand

prestressing and/or earthquake cables shall meet the following minimum requirements:

Item Specification

Nominal strand diameter 3/8" 1/2" 0.6"

Nominal area after galv.(in2) 0.089 0.153 0.217

Nominal weight (lbs/1000 LF) 303 541 739

Pitch (strand dia.) 12-16 12-16 12-16

Tensile strength (lbs) min. 21,400 38,200 52,700

Yield strength @ 1% extension (lbs) min.

16,000 28,500 39,500

Elongation in 24-inch at fracture min. 4.50% 4.50% 4.50%

Weight of zinc coating (oz/sq ft) min. 0.85 0.85 0.85

B. Hot-dipped galvanized seven-wire strand shall be manufactured in accordance with

ASTM A-416 prior to galvanizing.

C. Single wire prestressing material shall not be utilized in lieu of seven-wire strand prestressing material.

2.02 PORTLAND CEMENT

Portland Cement for the tank construction and shotcrete shall meet the requirements set out in

Section 03300 of these Specifications.

2.03 SHOTCRETE

A. Fine aggregates shall meet the requirements specified in Section 03300, "Cast-in-Place

Concrete", of these Specifications.

B. A well-graded coarse sand shall be used for all shotcrete applications.

C. Coarse sand shall generally consist of the following gradation:

Sieve Size % Passing by Weight

3/8 inch 100

No. 4 95-100

No. 8 80-100 No. 16 50- 85

No. 30 25- 60

No. 50 10- 30 No. 100 2 - 10


The fineness modulus shall fall between 2.70 and 3.00.

D. Rebound materials may not be reused in any form for shotcrete. Rebound is defined as

aggregate mixed with cement, which ricochets off the surface during the application of

shotcrete after collision with the harder surface, reinforcement, or aggregate particles

themselves. The amount varies with the position of the work, air pressure, cement content, maximum size and grading of aggregate, the amount of reinforcing and

thickness of layer.

E. Water shall meet the requirements set out in Section 03300, "Cast-in-Place Concrete", of these Specifications.

F. Air-entrainment and admixtures shall meet the requirements specified in Section

03300, "Cast-in-Place Concrete", of these Specifications.

G. All shotcrete, unless otherwise specified here-in, shall be fibrous reinforced. Such

material shall consist of 100 percent virgin polypropylene fibrillated fibers specifically

manufactured for use as concrete/shotcrete secondary reinforcement. The required

volume of fibers to be added per cubic yard of shotcrete shall be as specified in these Specifications.

The fibers shall be manufactured in accordance with ASTM C-1116 Type III 4.1.3 and

ASTM C-1116 (Ref. ASTM C-1018), Performance Level I5 outlined in Section 21, Note 17. Fibrous concrete reinforcement shall be as manufactured by the

FIBERMESH COMPANY, Chattanooga, TN, phone: (800) 635-2308, or equal.

Acceptable polypropylene fibers shall have the following physical characteristics:

1. Specific gravity = 0.91

2. Tensile strength = 80-110 ksi

3. Fiber length = graded per manufacturer

2.04 SHOTCRETE PROPORTIONING

A. Each one cubic yard of shotcrete material in the ready mix truck or mixer shall consist

of 0.1% (1.5 lbs. per cubic yard) polypropylene fibers as specified here-in and a mix

ratio of 3 lbs. of moist sand to 1 lb. of Portland cement. Up to 50 oz. of PRO- KRETE-R or POZZOLITH 300R may be added at the option of CONTRACTOR

during warm weather conditions.

B. Whenever night temperatures are expected to drop below 35F, shotcrete proportioning shall follow the provisions of ACI 306R, “Cold Weather Concreting”.

C. If the conditions exceed any combination of air temperature 88 degrees F or more, relative humidity of 60% or less and/or wind velocity of 10 miles per hour or more.

The methods described in Section 03052 HOT WEATHER CONCRETING

PROCEDURES, shall be utilized as applicable to the material and application of shotcrete.


D. If the batching procedure requires that smaller volumes of cement and sand be used, the

required cement-to-sand ratio shall still be strictly adhered to.

E. Additives other than PRO-KRETE-R or POZZOLITH 300R (such as POZZOLITH

300N or others) shall not be used unless specifically approved by the ENGINEER, after

careful consideration of its corrosive influence on prestressing steels.

F. If used by the shotcreter, the total volumetric air content of the shotcrete before placement shall not exceed 7 percent (plus or minus one percent) as determined by

ASTM C-173 or ASTM C- 231.

G. Unless otherwise specified on the Drawings, shotcrete cylinder strengths at 28 days shall be no less than 4,000 psi. Higher shotcrete cylinder strengths shall not permit a

reduction in the above specified cement contents. The cement content in the above mix

designs may be increased should the specified 28 day strength requirement not be met.

H. The polypropylene fibers and admixtures shall be added to the shotcrete at the time it is

batched and in the amounts specified in the approved mix design. Such additives shall

be mixed in strict conformance to the manufacturer's instructions and recommendations

for uniform and complete distribution. Each certificate of delivery supplied by the shotcrete supplier shall indicate the additive trade name, manufacturer's name and

amount per cubic yard added to each batch of shotcrete.

I. To insure proper penetration around the strand and proper conveyance of the material through the hose, a 5" to 7" slump of the mortar at the pump is recommended.

PART 3: EXECUTION

3.01 CIRCUMFERENTIAL PRESTRESSING EQUIPMENT

A. The circumferential stressing system shall produce a continuously, electronically (or

substantial equivalent) monitored permanent stress or force recording along the full

length of the strand as it is being applied. The stress variation in any strand at any point around the circumference should not be greater than +_1.5 percent of the ultimate

strength of the steel. In addition to this recording, any system which deflects the

tensioned strand between the tensioning device and the wall after it has left the tensioning device, shall provide a similar continuously monitored stress or force record

along the full length of the strand as it is being applied to the wall. These recordings

shall show that either before or after deflection, that the stress variation in any strand at

any point around the circumference shall not be greater than +_ 1.5 percent of the ultimate strength of the steel. No manual recorded force readings, such as hand-held

stressometers will be accepted. This requirement shall be strictly adhered to.

B. Any wrapping that does not meet the stress tolerances specified and/or cannot meet the requirements stated above will not be accepted and will be removed at

CONTRACTOR's expense. CONTRACTOR is responsible for all costs associated

with meeting the specified tolerances.

C. The prestressing system shall be capable of applying a continuous wrapped force at any point around the circumference within the specified tolerances. Circumferential

stressing systems based on jack-operated cable or rod-type tendons (such as those


placed inside of ducts incorporated in the corewall or placed manually around the

exterior of the corewall) will not be allowed.

D. Since wrapping systems that utilize single solid prestressing material will not provide

the desired bond between the prestressing material and the shotcrete and since single

solid prestressing material will not provide an adequate safety factor against failure,

only machine wrapping systems which utilize seven-wire prestressing strandwrapping will be allowed.

3.02 CIRCUMFERENTIAL PRESTRESSING APPLICATION

A. Wrapped strand shall be anchored to the wall at least once for every coil or reel. Submit method of anchorage shop drawings to the ENGINEER for review.

B. Permanently anchoring one strand to a previously wrapped strand shall not be

permitted.

C. Wrapped strand ends shall be joined by suitable splicing methods that will develop

90% of the full strength of the strand. Submit splicing method shop drawings to the

ENGINEER for review.

D. Use of different steel alloys in the splicing material shall not be permitted.

E. The clear vertical spacing between any two wrapped strands shall be at least 1.5 strand

diameters or 3/8 inch, whichever is larger.

F. Any wrapped strands not meeting the spacing requirements shall be spread by approved methods or must be removed.

G. All cracks, 0.02 inches and larger in the corewall and floor slab, shall be repaired per

Section 03740 EPOXY ADHESIVE INJECTION OF CRACKS IN CONCRETE MEMBERS of these specifications prior to circumferential prestressing of the tank

walls.

3.03 CIRCUMFERENTIAL PRESTRESSING OPERATIONS

A. The initial electronically (or substantial equivalent) recorded steel stress shall not exceed 75 percent of the guaranteed minimum ultimate strength (M.U.S.) of the steel at

any time during or after stressing.

B. An automatic, continuously electronically (or substantial equivalent) monitored permanent recording of the applied force, at any point on the strand, at any point on and

around the tank wall, must be made during the entire circumferential prestressing

application. All such recordings must be based on a continuous reading of the applied

force on the strand between the tensioning drum and the wall when, and as, the strand is being wrapped and laid on the wall.

C. The force setting of the wrapping stressing machinery shall be such that the applied

forces fall within the specified minimum or maximum stress or force limitations; the force setting shall be corrected immediately when the applied force falls outside the

required force tolerance limitations.


D. In the event that the stressing machinery is incapable of holding the applied force

within the specified stress or force range, the CITY will order, at the CONTRACTOR's expense, the removal and replacement of such machinery in favor of a different

stressing process capable of maintaining such tolerance requirements.

E. The initial force for the circumferential wrapped strand shall be no less than the

required initial force shown on the Drawings.

F. The continuous, electronically-produced applied-force chart produced during the

application of the strand wrapping becomes the property of the CITY.

G. Manual, individual or intermittent force readings taken on wrapped strand in full physical contact with the wall will not be accepted. Force readings based on anything

other than instantaneous force readings, as the strand is being tensioned, and wrapped

around the tank, will not be accepted.

H. An automatic, continuously electronically (or substantial equivalent) monitored and

simultaneously recorded force-elongation reading must be made for each vertical

stressing procedure.

I. Prior to wrapping, an initial 3/8" thick shotcrete layer shall be applied to the core wall after the surface has been prepared.

J. Wrapping may start when the concrete core wall has reached a compressive strength of

3,200 psi; however, under no circumstance shall the compressive stress exceed 55% of the concrete core wall compressive strength attained at that time.

K. In the event that gaps exceed 3/8 of an inch between the corewall and the applied strand

develop, wrapping shall be discontinued and the exterior wall surface shall be built up with shotcrete to reduce the gap within the 3/8-inch limit.

L. Wrapping over intermediate shotcrete coats or built-up shotcrete areas may commence

12 hours after the shotcrete has been applied or when the shotcrete has reached a

compressive strength of 250 psi, whichever is later.

M. The temperature of the prestressed material during application shall not be allowed to

increase by more than fifty degrees at any time during application due to the method of

stressing. No stressing system that pulls the prestressing material through a die to create a force is permitted.

3.04 SAFETY PRECAUTIONS

A. Every precaution shall be taken to keep personnel and visitors outside the danger area

of breaking strands or bars.

B. At no time shall anyone stand in the line of stressed vertical tendons or stressed strand.

C. No work shall be performed by anyone, other than the prestressing crew, within 100

feet of the wrapping operation or the application of the vertical threadbar stressing operation.


D. Where access to the site by persons other than the prestressing crew is outside the

CONTRACTOR's control, while prestressing work is in progress, CONTRACTOR shall erect protective fencing to prevent breaking strand from endangering such

persons.

E. Welding to anchor plates after the threadbars have been assembled shall not be

permitted. In addition, prestressing steel shall not be used as a "ground" for welding operations.

3.05 EXISTING WALL SURFACE PREPARATION

A. Exterior surfaces of reservoir walls shall be prepared prior to the application of shotcrete to remove all deteriorated concrete and bond-inhibiting contaminants. The

surface preparation shall achieve a minimum profile of ICRI Concrete Repair Manual,

CSP5 over a minimum of ninety percent of the surface being prepared.

B. In order to mitigate environmental concerns, conform to environmental constraints, and

achieve the desired profile, the CONTRACTOR shall utilize either a self-contained

mechanical etching or shot blast system combined with a vacuum recovery system, or a

high pressure water jetting system with dust suppression equipment. Abrasive blasting systems that rely on sandblasting or steel shot without a vacuum recovery system or

systems that have not been used successfully in the past to prepare surfaces for

shotcreting and strandwrapping shall not be allowed.

3.06 SHOTCRETE EQUIPMENT

A. Shotcrete mixing shall be in conformance with the requirements of Section 03300,

"Cast-in-Place Concrete", of these Specifications.

B. The delivery equipment shall be of an approved design and size which has previous

given satisfactory results in similar work.

C. The equipment must be capable of discharging mixed materials into the hose under

close control and it must be able to deliver a continuous smooth stream of uniformly mixed material at the proper velocity to the discharge nozzle, free from slugs of any

kind.

D. The nozzle shall be of a design and size that will insure a smooth and uninterrupted flow of materials.

E. Delivery equipment shall be thoroughly cleaned at the end of each shift.

F. Equipment parts shall be regularly inspected and replaced as required.

G. The air capacity of the compressor shall be large enough that the minimum amount of air to be available at the nozzle shall be no less than 400 CFM, irrespective of whether

or not air from the same air supply is used for other purposes.

3.07 SHOTCRETE APPLICATION PROCESS

A. Shotcrete shall be applied under the wet mix process only.


B. Nozzles shall be mounted on power driven machinery enabling the nozzle to travel

parallel to the surface to be sprayed at a uniform linear or bi-directional speed.

C. The nozzle shall be kept at a constant distance from the surface, always insuring a right

angle spray direction of the material to the surface.

D. Hand operated nozzles and shotcrete operations dependent on the performance of the

nozzleman will not be accepted except where additional shotcrete is needed to correct flat areas or for architectural surface treatments.

E. Grout materials shall be delivered to the jobsite in ready-mix trucks from approved

batching plants. However, job mixing will be accepted provided automatic weigh batch plants are used.

F. The sand, cement and water shall be premixed before being pumped through a 2"

minimum hose by specially designed mortar pumps.

G. The high velocity impact shall be developed pneumatically by injecting compressed air

at the nozzle.

3.08 SHOTCRETE PLACING AND FINISHING

A. Shotcrete shall be applied in a steady, uninterrupted flow. Should the flow become intermittent for any cause, the machine operator shall direct the nozzle away from the

work until it again becomes constant, or shut off the flow of materials.

B. The nozzle shall be held at approximately right angles to the surface and shall be kept at the proper and constant distance from the surface dictated by good practice standards

for the type of application, type of nozzle and air pressure employed.

C. Sufficient time shall be allowed for each layer of shotcrete to set up so the next layer of shotcrete can be applied without sagging.

D. The shotcrete application shall start at the bottom of the wall and move upward until all

wrapped strands have been covered. Subsequent shotcrete layers may be applied from

the top down or from the bottom up at the discretion of the CONTRACTOR.

E. While the nozzle travels around the tank, the nozzle shall be raised or lowered at a

uniform rate that provides an adequate overlapping of coatings and a uniform finish.

F. The nozzle shall be spiraled up or down around the tank, ending either at the top or bottom of the wall or at the termination of a partial-height strand layer.

G. The wall and/or intermediate layers of shotcrete may be wet down in order to achieve a

saturated surface-dry condition prior to the application of new shotcrete. The moisture

absorption by layers previously applied is relied upon to improve the bond and strength of the shotcrete material and reduce drying shrinkage of the applied shotcrete.

H. The application of the shotcrete in the number and thickness of layers specified here-in

is mandatory for proper penetration of shotcrete behind prestressing material and to reduce shrinkage due to variable drying of the shotcrete.


I. Each layer of wrapped prestressing steel shall be covered with a minimum thickness of

3/8-inch shotcrete over the steel.

J. The shotcrete cover coat, over the final strand layer, shall be applied in at layers of

equal thickness to provide the required thickness of this coat.

K. Each layer of shotcrete shall be completed for the full circumference and full height of

the layer before the next layer of shotcrete may be applied.

L. All shotcrete coatings shall be built up in layers no greater than 3/4 inch in thickness

until the final required thickness has been obtained. The CONTRACTOR shall

demonstrate by a reliable means that each layer applied is the proper thickness.

M. Unless otherwise specified on the Drawings, the minimum shotcrete cover over all

wrapped steel shall be 1.5 inches.

N. If required on the Drawings, after the specified shotcrete cover over the wrapped prestressing strand has been completed, the exterior surface shall be given an

acceptable float finish true to line and curvature of the tank and to details shown on the

Drawings.

O. If a float finish is required on the Drawings, plaster or hand-applied shotcrete may be used to build up and level the surface to obtain the desired surface finish and

projections.

P. The finish coat mix (if a smooth float finish is required on the Drawings), shall consist of a minimum of one sack of cement for each 3-1/2 cubic feet of moist plaster sand.

Q. If no finish requirements are shown on the Plans, it is intended to have a natural

original gun finish of the shotcrete cover coat.

R. CONTRACTOR shall take every possible precaution to protect adjacent buildings,

concrete surfaces, vehicles, equipment, etc., from being damaged by overshooting

shotcrete and by materials carried away by the wind and shall be responsible for the

cost to clean overspray of shotcrete from these items.

S. Overshot shotcrete and rebound material deposited on the tank roof slab shall be

removed before it adheres to the concrete surface.

T. CONTRACTOR shall pay for all damages caused by the shotcrete operation under this contract.

3.09 SHOTCRETE TESTS

All shotcrete operations, testing, and prequalifying, shall conform to the entire Section 1910

of the 2013 California Building Code (CBC).

3.10 HAND PLACED SHOTCRETE FOR REPAIRS ONLY


A. To insure a high quality shotcrete application, the CONTRACTOR shall satisfy the

ENGINEER that the nozzleman has had sufficient and acceptable experience in the application of structural shotcrete.

B. Pool and ditch shotcrete construction experience will not be considered as experience

for qualifying the nozzleman, unless approved by the ENGINEER.

C. The nozzleman shall be capable of applying thin coats of even and uniform thickness.

D. The nozzleman shall be a certified nozzle man in accordance with ACI 506.3R before

he may start any work.

3.11 RESTRICTIONS ON SHOTCRETE OPERATION

A. Shotcrete shall not be applied under such strong wind conditions that a considerable

amount of cement and moisture will be removed by the wind from the mortar spray

between the nozzle and the surface on which the shotcrete is applied.

B. Shotcrete may be applied in cold weather provided the wall surface is not frozen.

C. The temperature during the day must be expected to rise to at least 40F and the night temperature of the night after the shotcrete application must not be expected to drop

below 27F.

D. The use of Type III Portland cement is required (when readily available) in the event

shotcrete is applied at temperatures below 40F. The CONTRACTOR may apply shotcrete under these conditions solely at his own risk.

E. Whenever rain or frost has damaged shotcrete not yet set, the shotcrete must be removed and replaced.

F. If there is a possibility of damage, the CONTRACTOR shall consult with the

ENGINEER to determine if the shotcrete has been damaged by rain or frost before

applying any additional layers.

3.12 SHOTCRETE WATERCURING

A. Intermediate layers of shotcrete are not required to be cured if an additional shotcrete

layer is applied on the entire wall surface within 12 hours of completing the application of the previous layer. Keep shotcrete layer damp by hand curing or other means after

12 hours has elapsed since the layer was applied until the next shotcrete layer is

applied.

B. An indiscriminate use of continuous watercure for intermediate layers shall be avoided.

C. The final completed shotcrete layer, which is not required to receive any additional

coatings, shall be cured with plastic sheeting for a period of at least seven (7) days.

Plastic sheets used shall prevent loss of moisture from shotcrete as much as possible. Membrane curing methods utilizing curing compounds or wax-based residuals will not

be permitted.


D. Wall coatings if required and specified in Section 09900, "Painting and Coating", shall

be applied no later than five (5) days after completion of the curing. If conditions make it impossible to apply coatings within the five (5) day period, or if no coatings are

required, shotcrete shall be cured for a period of ten (10) days instead of the seven (7)

days specified above.

3.13 CLEANING AND WATERPROOFING

A. After construction is completed, the interior of the tank shall be completely hosed out

and cleaned of all dirt and loose material.

B. Roof, floor and wall-footing cracks, which may have developed from drying shrinkage, shall not be taped or chipped out and caulked. All cracks larger than 0.02 inches shall

be repaired in accordance with Section 03740 EPOXY ADHESIVE INJECTION OF

CRACKS IN CONCRETE MEMBERS and shall be completed prior to applying the interior coating and exterior waterproofing at no additional cost to the CITY.

C. Exterior Waterproof Coating: The exterior coating shall be applied and cured prior to

backfilling in accordance with Section 07182 - RESERVOIR/VAULT WATER-

PROOFING.

3.14 DISINFECTING AND FILLING

A. Prior to filling, testing and disinfecting, the reservoir shall be swept clean and the

walls, floor, columns, and underside of the roof shall be sprayed with a high pressure stream of potable water to wash down all dust, dirt, etc. The high-pressure hose and

nozzle shall be of sufficient size to deliver a minimum flow of 50 gpm. All water, dirt,

and foreign material accumulated in this cleaning operation shall be collected and removed from the reservoir.

B. The reservoir shall be disinfected by chlorination. Chlorination shall be performed in

accordance with the requirements of AWWA C652, Method 2, with the following

modifications.

C. After the tank is cleaned and waterproofed, water containing 50 PPM of chlorine shall

be sprayed on all walls, columns, underside of roof areas, inlet piping, outlet piping,

and drain piping.

D. Water containing 50 PPM of chlorine shall be brought to such a depth that when the

tank is filled with potable water, the resulting chlorine solution is 1.5 to 2 PPM. The

water containing 50 PPM of chlorine shall stand for 24 hours prior to filling the tank.

E. The tank shall be filled in approximately eight-foot increments with 8 normal working hours between each increment for observation of possible leaks through the subdrains,

the reservoir wall, or the wall-footing joint. The filling of the reservoir shall be

coordinated with the OWNER. The OWNER will supply the water for the initial filling of the reservoir at no cost to the CONTRACTOR.

F. If only damp spots and small puddles of water are noted, the 8-foot incremental filling

can continue. If major leaks are noted, they should be thoroughly investigated prior to


continuing to fill the tank. All leaks shall be repaired to the satisfaction of the CITY at

no additional cost to the CITY.

G. The tank should only be filled during normal working hours. At the end of each day the

reservoir and perimeter drain should be checked for evidence of any kind of leakage.

H. The chlorine concentration residual shall be monitored and adjusted while filling, if

necessary, so that when the reservoir is full the resulting chlorine concentration is approximately 1.5 to 2 PPM.

I. After filling the reservoir to the overflow level, there shall be a 24 hour soak period.

After the 24 hour soak period, a water sample shall be taken for bacteriological testing. After an additional 24 hour soak period, a second water sample shall be taken for

bacteriological testing. The disinfection process shall be accepted if samples taken for

both bacteriological tests conform to AWWA Standard C-651 and are found to be satisfactory.

If either test is positive, the CONTRACTOR shall correct the cause of the

bacteriological contamination, rechlorinate and retest the reservoir until two

consecutive satisfactory bacteriological test results are obtained, at no additional cost to the CITY. If bacteriological testing results continue to be positive, the contractor shall

drain the reservoir, re-disinfect, fill, and retest the reservoir water, all at no additional

cost to the CITY.

J. If the reservoir fails testing for bacteriological contamination or for leakage and water

must be discharged, cost of additional water to fill the reservoir will be deducted from

the total contract price.

K. Conduct testing for volatile organic compounds (VOCs) per Los Angeles County

Department of Public Health (DPH) requirements.

3.15 WARRANTY PERIOD PROVISIONS

A. This section shall be applicable during the entire specified warranty period of the tank.

B. A warranty inspection of the complete reservoir shall be conducted during the eleventh

month following the Notice of Completion. Representatives of the general contractor

shall attend this inspection and provide all necessary work and equipment required for the inspection such as lighting, ventilation, and safety equipment. All work found to be

defective at this time shall be repaired or replaced in accordance with the original

specifications and to the satisfaction of the CITY. The CONTRACTOR shall clean and

disinfect the reservoir after repairs to the interior are completed, or, disinfect the reservoir if no repairs to the interior are required, after the tank inspection. If the tank

was seeded, the CONTRACTOR shall remove the seeding material residue.

C. All equipment, materials, and labor required to perform the inspection, make the necessary repairs, and disinfect the tank shall be provided by the CONTRACTOR at no

additional cost to the CITY except that the CITY will provide water for the initial

filling of the tank with the same restrictions as provided in the initial testing period. The CONTRACTOR will be responsible for repairing any leaks that may develop as a

result of any warranty work.


D. If the eleventh month falls on or between the date of May 1 and September 30, then the

inspection may be delayed and shall be performed no earlier than October 1 which would be longer than eleven months.

END OF SECTION

Date post:	17-Feb-2022
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SIERRA MADRE RESERVOIR RAHABILITATION PLAN NO. 1178

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