11 thuyetminh drainage and orther

METHOD STATEMENT GMS Ben Luc Long Thanh Expressway Project Package A5 Civil Works Km 32+450 to Km 35+900 DRAINAGE AND OTHER WORKS TABLE OF CONTENTS I CONSTRUCTION METHOD FOR PILE CULVERT, BOX CULVERT[.]

DRAINAGE AND OTHER WORKS

TABLE OF CONTENTS

DRAINAGE

EXISTING IRRIGATION CHANNELS.

MANHOLES, INLETS, AND OUTLETS.

VIII CONSTRUCTING MORTARED STONEWORK STRUCTURES

I CONSTRUCTION METHOD FOR PILE CULVERT, BOX CULVERT

This section described construction method for constructing new reinforced concretepipe culverts, reinforced concrete box culverts, underpass box culverts and stormwater drains This work shall include headwalls, inlet and outlet structures andreinforced concrete pipe cradles, as well as associated erosion and scour protectionworks The Contractor will build all of works in accordance with the Drawings andSpecification and at the locations indicated by the Project Managerthe Engineer.The pile culvert and box culvert will built in Package 5(Km32+600 - Km42+00):

acceptanceThe construction of reinforced concrete box culverts, head walls, inlets, outlets andother reinforced concrete drainage structures shall be in accordance with theprovisions of Section “Concrete and Concrete Structures”

All finished surfaces of concrete, which are not permanently covered shall; have asmooth fair finish, be even and free from waves, be finished true to line/levels andcontours, be free of blow holes, be free of honeycombing and air bubbles and the like.Any holes left by bolts used to position the formwork shall be filled in with epoxygrout flush with the surrounding surfaces.

All reinforcing steel used in the works shall conform to the requirements specified inSection, “Reinforcing Steel and steel works”

Granular material for bedding shall be in accordance with Paragraph 4.2, Table 4 ofVietnamese Standard TCVN 7570-2006 and subject to the approval of the Engineer.Lean concrete for bedding shall be class CIO bedding or blinding concrete inaccordance with the requirements of Specification Section “Concrete and ConcreteStructures”

Stone Masonry and mortar used in the works shall conform to the requirementsspecified in Section “Stone Masonry”

In case of requirement in drawings, Porous Backfill or Filter Material shall be inaccordance with the provisions of Section “Porous drainage and Backfill” or asdirected by the Project Managerthe Engineer

The Contractor shall furnish shop drawings containing the constructions details forculverts and concrete drains indicated on the Drawings and as directed by the ProjectManagerthe Engineer Shop drawings shall be submitted to the Project ManagertheEngineer prior to the start of the construction of culverts and concrete drains.Construction of culverts and concrete drains shall begin only after the ProjectManagerthe Engineer gives approval of the shop drawings to the Contractor

Temporary drainage work shall be in place and operating before beginningembankment works, or as directed by the Project Managerthe Engineer

No subgrade preparation or pavement overlay work (either in the road or the shoulderareas) shall commence until the culverts, headwalls, and other minor structures belowthe subgrade level along that particular section of the project are complete.

Precast Pipe culvert, precast bearing including Pipe culvert D1000, D1500, bearingindicate in design drawings

Reinforced Concrete Culverts shall be precast reinforced concrete class C25 and shallconform with Specification Section “Concrete and Concrete Structures” Pipes shall

be laid with male/female joints and reinforcement in all pipes shall consist of spiralsteel cages with longitudinal bars all as indicated on the Drawings unless otherwiseapproved by the Engineer

Bearings to support the pipes shall be of the numbers and types indicated on theDrawings and subject to the approval of the Engineer They shall be of precastreinforced concrete of concrete class C20 and shall conform with SpecificationSection “Concrete and Concrete Structures”

No precast concrete products shall be cast until the Engineer has approved themanufacturing plant and the equipment therein The Contractor shall ensure that nodamaged precast concrete items are taken to Site or installed on Site Damage isdeemed to include, inter alia, honeycombing, chips, cracks and blemishes inappearance In the event the precast concrete items are damaged they shall be removedfrom the Site and never used in the Works No repairs or patching will be accepted bythe Engineer whether the damage occurs on the Site or before or after delivery to Site.The Engineer shall periodically inspect the precast concrete manufacturing plants toensure compliance with the approved method statements for manufacturing TheContractor will supply material samples for laboratory testing to ensure qualitycompliance and will make the necessary arrangements to facilitate the inspections bythe Engineer

Such inspections shall include the inspection of reinforced precast concrete items Allprecast items shall be marked with a unique reference and no item shall be delivered

to the construction Site without approval from the Engineer

In order to maintain the quality of the precast concrete items the Contractor shall castthese in a factory off the Site

Execution of concrete, reiforced steel, formwork comply with the requirementsspecified in section “Concrete and Concrete Structures”

Execution order is described as followings:

4.2.1 Preparation of casting area:

Units are casted in flat area, enough large to cast concrete and placing material

The casting area is leveled and compacted to not be subside during casting and placingmaterial as well as moving eqiupment and crane for installation units.

The casting area is reinforced with concrete, thickness of concrete layer 10-15cm

4.2.3 Preparation for material

All material for executing units, design for component of concrete mixture must beapproved by Project Manager prior to put in to use and comply with the requirements

as indicated in article above 1.3 – “Material requirements”

4.2.4 Reinforced steel works

Reinforced steel is processed as Design Document which has been approved byProject Manager

Steel is worked in to set for each culvert units Quantity of set for pouring concretedaily must be accepted by Project Manager prior to the start of the execute of concreteReinforced steel works conform to the requirements specified in section TCVN5709:2009 (Hot-rolled cacbor steel uses on construction) conform to the requirements

as indicated section, “Reinforcing Steel and steel works”

Installation of reinforced steel in to casting mould must ensure the requirement forthickness of protective concrete layer as specified in Design Document Use the trestle

to control the thickness of protective concrete layer (if necessary) The trestle is made

of material which assures the intensity and is similar colour to concrete and approved

Installed-formworks ensure be firm and stable during placing concrete The slab offormwork must be sealed to ensure not to loss the cement water during placing andcompacting concrete

The forwork is removed as having result of testing sample for concrete intensity.Theminimized intensity of concrete for removal formwork is approved by ProjectManager in the first test

4.2.6 Place and compaction of concrete:

Concrete is mixed by mixer according to mix design approved by Project Manager

Concrete need to tested the slump before placing, sampling under witnessed by ProjectManager or authorized person.

After pouring concrete on formwork, will be compacted with specialized equipment.These equipments operate inside the narrow formworks, ensuring not to displace thesteel bars or trestle The vibrator equipments attach outer surface of formwork areencouraged to use

Process of pouring and compacting concrete conform to the requirements specified insection “Concrete and Concrete Structures”

4.2.7 Concrete curing

Methods ang processes of concrete curing conform to the requirements specified insection “Concrete and Concrete Structures”

4.2.8 Loading, transporting of concrete unit

Concrete units are only allowed to move out of casting area in case of concretecompressive strength for each sample in lift of concrete meets 80% minimum comparewith the requirement concrete strength for one unit

Concrete units are put up and down carefully They will be transported vertically toavoid impacting, bearing points and direction of reaction when transporting andstoring are as same as the last installation stage

All concrete units will be marked separate and permanent to write clearly type ofconcrete unit and date of concrete

4.3.1 Construction plan and organization

The positions of box culverts are for construction of service road; the service roadcontractor shall carry out construction of entire culvert length At the culvert positionsthat the service road or pipe culvert can not be constructed, the contractor shall ensuretransport by construction of 1/2 the lower culvert first After that, the remained 1/2culvert in the lower section shall be constructed; these culvert shall be strengthenedand opened to its edges by disposed stone or gravel aggregate foundation The serviceroad shall be large enough for 2 directionally safe traffic movement The service roadshall be arranged with sufficient signal posts, signal plate, lighting (at night) withtraffic control staffs at 2 ends continually during construction period Horizontaldrainage culvert shall be arranged temporarily for not affecting the culvertconstruction activities as well as the existing discharge flow of the road, residentialarea and irrigational activities

4.3.2 Excavation of culvert trench

Excavation of culvert trenches will execute conform to the requirements specified insection “Excavation and backfill for structure”

Construction method and construction order as follows:

trenches Transporting waste material to regulated area

which around the culvert) in order to execute body culvert and embank bothsides of culvert Slope of trenches will be executed comply with stability oftrenches’s geology

cofferdam in method of constructing trenches It will be needed to construct asmall ditch system around inlet to collection water and use pump to pump waterout of trenches

the contractor shall inform the Engineer for on-time solution to keep progress

excavated area shall be backfilled by materials of little deformation underpressure as sand, gravel sand or concrete with the same mark with the trenchesand shall be in compact with the foundation The material type and compactrequirements shall be in accordance with regulated design documents or with theinstructions from the Engineer

allowed install when trenches be executed as Design Drawings, be accepted byProject Manager

4.3.3 Instalation of precast units

The Contractor shall lay reinforced concrete cradles and pipes carefully The hubs orgrooved ends shall be up grade The spigots or tongued ends shall be fully entered intothe adjacent hub or groove and be true to the required lines and grades

Before laying succeeding sections of reinforced concrete pipe which do not requirecambering, the Contractor shall plaster the lower half of the hub of the precedingsections on the inside with Portland cement mortar The mortar shall be sufficientlythick to bring the inner surface of the abutting pipes flush and even The Contractorshall plaster the upper half of the spigot of the succeeding pipe with mortar at the sametime

All Pipe or Box Culverts shall be laid and fitted together such that the joint sealantforms a full and effective seal around the full circumference of the Pipe or the Box

Culverts Joint sealants shall be placed such that any joints or overlaps in the sealantare at the top of the Pipe or the Box Culverts.

After laying the reinforced concrete pipe, the Contractor shall fill the remainder of thejoint with sufficient mortar to form a bead around the joint The Contractor shall wipethe inside of the joint and finish it to a smooth and even surface The mortar on theoutside shall be cured and remain damp for two days or until the Project ManagertheEngineer allows backfilling to proceed

4.3.4 Culvert Headwalls, Inlets, and Outlets

Unless otherwise shown on the Drawings, the Contractor shall construct all culvertaprons, wing-walls, and headwalls using reinforced concrete of the class indicated onthe Drawings and in accordance with requirements and provisions of section

“Concrete and Concrete Structures” Scour protection works will normally bemortared rip-rap unless indicated in the Drawings

After constructing culvert trenches as described in article 1.4.3 (b), Work items forexecuting in-situ box culvert and underpass box culvert comply with order as follows:

culvert;

culvert;

to unti – erosion of culvert downstream

All works for executiong concrete, reinforced steel, formwork conform to therequirements specified in section “Concrete and Concrete Structures” Furthermore,these works need to comply with specific requirement as follows:

Reinforcement erection in accordance with the design drawings The steel bars are

discalced and cleaned Reinforcement connection methods as welding or binding shall

be carried out right in accordance with regulations Reinforcement frames, fenders orrebars shall be laid on the skids; the cement skids have the similar thickness to theprotection concrete thickness; the steel cable shall be lined in the skids to bind them

on the reinforcement The skids laid on the suitable positions basing on thereinforcement density but not over 1m from a skidding place The salvage shall not beused to skid the outer surfaces of the structures Frame and fender of the reinforcement

shall be binded tightly and not deflecting when installed in the platform and duringconcrete casting The pre-erected parts do not affect to the parts erected afterwards.The reinforcement installation shall be accepted by the SC before concrete casting.

Erection of the reinforcement platform: Before erection, the platform shall be cleaned

and an anti-adhesive oil layer shall be applied The platform shall be erected by crane incooperation with manpower and closely connected by bolts It shall be noted to erectthe scaffolding and bearing braces to ensure the stability of the platform during concretecasting The cleats shall be arranged for easy disassembling of the scaffolding andplatform when the concrete reaches the allowed strength

Concrete casting and vibration: Equipments and materials as well as manpower

shall be checked before concrete casting The materials shall be sufficient forcontinuous concrete casting and the concrete batching machine shall operate well

shall be casted in the silo right after poured out from the batching machine.Crane shall be used to take to concrete to right place

adjustment as in the design Sample shall be casted for later test The aggregatemeasurement system shall also be checked to ensure the design batching ratio forconcrete

concrete shall not be overt 1m because of making concrete stratification

below starts to freeze

the concrete layer shall be as follows:

1.25 of the effective length of the needle arm

for the structure with much reinforcement, or shall be 25cm for the reinforcement structure

effective radius of the vibrator The vibrator shall not penetrate to thelower concrete layer casted before, if this layer is freezing

-5cm Vibrating through the reinforcement shall not be done

- Concrete casting shall be done continuously until part by part of the constructionworks is completed.

Concrete maintenance: After concrete casting no later than 10 -12 hours in winter or

4 - 5 hours in summer, watering shall be done and the concrete surface shall be

done in the first 3 days and 3 nights: in daytime, watering shall be done after every 3hours and in night time, watering shall be done for 1 – 2 times, then at least 3 times ofwatering in a night is required

Platform disassembling: Culvert wall platform (the non-load-resistant,

non-strength-resistant structure) shall be disassembled when the concrete reaches the strength ofminimum 25kg/cm2 For the strength-resistant scaffolding and platform, concreteshall reach 70% of the designed strength then the platform can be disassembled Theplatform disassemble shall be done carefully for not creating the thrust to the concretestructure Before and after strength-resistant platform disassemble, the slump of thedeformation area and structure shall be measured

The Contractor shall take the fill to a minimum height of 500 mm above the top of thepipe Unless in a trench, the fill shall extend for a minimum distance of one and a halfdiameters from the centerline of the pipe on each side of the pipe The Contractor shalltake special care to compact the backfill under the haunches of the pipe properly Thebackfill shall be brought up evenly on both sides of the haunches for the entire pipelength

Heavy earth moving and compacting equipment shall not operate closer than 1.5meters from the culvert until the cover above the pipe is at least 500 mm Light weightequipment may operate within the limitation mentioned above provided the backfill isplaced and compacted at least 300 mm above the top of the pipe Notwithstandingthese conditions, the Contractor shall be responsible for and shall rectify any damageresulting from such operations

The Contractor shall clean all culverts until they are free of loose debris, soil, and allforeign material The Contractor shall keep the culverts clean and maintain them in anoperating condition throughout the Contract Period The Contractor shall only permit

water to flow through the cleaned culvert after the Project Managerthe Engineerinspects and approves the culvert.

DRAINAGE

This work shall consist of furnishing, constructing and/or installing side drainagetypes of structures built, slope drainage types of structures built in conformance withthe Contract Drawings Included are such items as trapezium shaped, rectangleshaped, and bench ditch, stepped drop, ditch at top of slope

To construct roadside Ditches using mortared stonework, concrete, reinforcedconcrete, or precast concrete as shown on the Drawings or directed by the Engineer.The Contractor shall submit to the Engineer, for his approval, details and samples ofmaterials he intends to use for the construction of Ditches

Granular material for bedding shall be in accordance with Paragraph 4.2, Table 4 ofVietnamese Standard TCVN 7570 - 2006 and subject to the approval of the Engineer.Lean concrete for bedding shall be class C10 bedding or blinding concrete inaccordance with the requirements of Specification Section “Concrete and ConcreteStructures”

All reinforcing steel shall conform with the requirements specified in SpecificationSection “Reinforcing Steel”

Drainage excavation is combined with embankment excavation, and then the drainageform shall be fixed manually.

Drainage before construction shall be cut off with abundant soil, the jumpingcompactor shall be used to compact the drainage bedding, assuring the gradient,compactness and the flat of the slope and drainage groove in conformity with thedesign

Positioning for pipe driving and line stretching to create the form and limited surface,

in parallel with the flat surface, shall be carried out

Drainage foundation excavation shall conform to the requirements of Section

“Excavation and backfill for structure”

Construction side drainage concrete, shall conform to the requirements of section

“Concrete and concrete structure”

Basic construction order as follows:

Construction bench ditch concrete, ditch at top of slope concrete, shall conform to therequirements of section “Concrete and concrete structure”

Supplying concrete to construction location, transporting to bench ditch, top ditch bycapstan system or hoist

Basic construction order as follows:

Rip-rap and mortar for stepped drop structures shall conform to the requirements ofsection “Mortared Stonework”