06 4 iok a1 DRAINAGE SYSTEM

CIVIL WORKS CONTRACT PACKAGE A1 (KM 65+000-KM81+150)- DA NANG – QUANG NGAI SECTION CONSTRUCTION METHOD FOR DRAINAGE SYSTEM TABLE OF CONTENTS I CONSTRUCTION METHOD FOR PILE CULVERT, BOX CULVERT AND UNDERPASS BOX CULVERT II DETAIL CONSTRUCTION METHOD FOR SIDE DRAINAGE AND SLOPE DRAINAGE III DETAIL CONSTRUCTION METHOD FOR IMPROVEMENT RELOCATION OF EXISTING IRRIGATION CHANNELS AND IV DETAIL CONSTRUCTION METHOD FOR CATCH BASINS, MANHOLES, INLETS, AND OUTLETS 1/ 22 PHUONG THANH TRANCONSIN – GRBCC JV CIVIL WORKS CONTRACT PACKAGE A1 (KM 65+000-KM81+150)- DA NANG – QUANG NGAI SECTION CHAPTER III: CONSTRUCTION METHOD FOR DRAINAGE SYSTEM I CONSTRUCTION METHOD FOR PILE CULVERT, BOX CULVERT AND UNDERPASS BOX CULVERT Description This section described construction method for constructing new reinforced concrete pipe culverts, reinforced concrete box culverts, underpass box culverts and storm water drains This work shall include headwalls, inlet and outlet structures and reinforced concrete pipe cradles, as well as associated erosion and scour protection works The Contractor will build all of works in accordance with the Drawings and Specification and at the locations indicated by the Engineer Reference Standards 22TCN159-86: Specifications for construction and acceptance precast reinforced concrete TCVN 9116:2012: Pre-cast RC box culvert Technical requirements TCVN 9113:2012: Drainage reinforced concrete pipe TCVN 4453 – 1995: Monolithic concrete structure construction and acceptance – Norm of of The construction of reinforced concrete box culverts, head walls, inlets, outlets and other reinforced concrete drainage structures shall be in accordance with the provisions of Section “Concrete and Concrete Structures” Material requirements 3.1 Concrete Concrete used for all structural work described in this Specification section shall be of the classes indicated on the Drawings and shall conform to the requirements specified in Section “Concrete and Concrete Structures” All finished surfaces of concrete, which are not permanently covered shall; have a smooth fair finish, be even and free from waves, be finished true to line/levels and contours, 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 epoxy grout flush with the surrounding surfaces 3.2 Reinforcing Steel for Concrete All reinforcing steel used in the works shall conform to the requirements specified in Section, “Reinforcing Steel and steel works” 3.3 Bedding 2/ 22 PHUONG THANH TRANCONSIN – GRBCC JV CIVIL WORKS CONTRACT PACKAGE A1 (KM 65+000-KM81+150)- DA NANG – QUANG NGAI SECTION Granular material for bedding shall be in accordance with Paragraph 4.2, Table of Vietnamese Standard TCVN 7570-2006 and subject to the approval of the Engineer Lean concrete for bedding shall be class CIO bedding or blinding concrete in accordance with the requirements of Specification Section “Concrete and Concrete Structures” 3.4 Stone Masonry Stone Masonry and mortar used in the works shall conform to the requirements specified in Section “Stone Masonry” 3.4 Porous Backfill or Filter Material In case of requirement in drawings, Porous Backfill or Filter Material shall be in accordance with the provisions of Section “Porous drainage and Backfill” or as directed by the Engineer 3.5 Backfill Filling material used in the works shall conform to the requirements specified in section “Excavation and Backfill for structure” Detail construction method for pipe culvert, box culvert and underpass box culvert 4.1 Preparation for construction The Contractor shall furnish shop drawings containing the constructions details for culverts and concrete drains indicated on the Drawings and as directed by the Engineer Shop drawings shall be submitted to the Engineer prior to the start of the construction of culverts and concrete drains Construction of culverts and concrete drains shall begin only after the Engineer gives approval of the shop drawings to the Contractor Temporary drainage work shall be in place and operating before beginning embankment works, or as directed by the Engineer No subgrade preparation or pavement overlay work (either in the road or the shoulder areas) shall commence until the culverts, headwalls, and other minor structures below the subgrade level along that particular section of the project are complete 4.2 Construct for Precast Concrete Elements Reinforced Concrete Culverts shall be precast reinforced concrete and shall conform with Specification Section “Concrete and Concrete Structures” Pipes shall be laid with male/female joints and reinforcement in all pipes shall consist of spiral steel cages with longitudinal bars all as indicated on the Drawings unless otherwise approved by the Engineer Bearings to support the pipes shall be of the numbers and types indicated on the Drawings and subject to the approval of the Engineer They shall be 3/ 22 PHUONG THANH TRANCONSIN – GRBCC JV CIVIL WORKS CONTRACT PACKAGE A1 (KM 65+000-KM81+150)- DA NANG – QUANG NGAI SECTION of precast reinforced concrete of concrete and shall conform with Specification Section “Concrete and Concrete Structures” No precast concrete products shall be cast until the Engineer has approved the manufacturing plant and the equipment therein The Contractor shall ensure that no damaged precast concrete items are taken to Site or installed on Site Damage is deemed to include, inter alia, honeycombing, chips, cracks and blemishes in appearance In the event the precast concrete items are damaged they shall be removed from the Site and never used in the Works No repairs or patching will be accepted by the 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 to ensure compliance with the approved method statements for manufacturing The Contractor will supply material samples for laboratory testing to ensure quality compliance and will make the necessary arrangements to facilitate the inspections by the Engineer Such inspections shall include the inspection of reinforced precast concrete items All precast 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 cast these in a factory off the Site Execution of concrete, reiforced steel, formwork comply with requirements specified in section “Concrete and Concrete Structures” the Execution order is described as followings: a) 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 placing material as well as moving eqiupment and crane for installation units The casting area is reinforced with concrete, thickness of concrete layer 10-15cm b) Preparation for material All material for executing units, design for component of concrete mixture must be approved by Project Manager prior to put in to use and comply with the requirements c) Reinforced steel works Reinforced steel is processed as Design Document which has been approved by Project Manager 4/ 22 PHUONG THANH TRANCONSIN – GRBCC JV CIVIL WORKS CONTRACT PACKAGE A1 (KM 65+000-KM81+150)- DA NANG – QUANG NGAI SECTION Steel is worked in to set for each culvert units Quantity of set for pouring concrete daily must be accepted by Project Manager prior to the start of the execute of concrete Reinforced steel works conform to the requirements specified in section TCVN 5709:2009 (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 for thickness 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 by Project Manager d) Formworks: Formworks and preparation of formwork conform to the requirements specified in section “Concrete and Concrete Structures” Formwork for precasting concrete must use shaped formwork and made of shaped steel and flat steel sheet When installation, the formwork will be lubricated with anti-adhesive material The anti-adhesive material must be colourless and approved by Project Manager before using Installed-formworks ensure be firm and stable during placing concrete The slab of formwork must be sealed to ensure not to loss the cement water during placing and compacting concrete The forwork is removed as having result of testing sample for concrete intensity.The minimized intensity of concrete for removal formwork is approved by Project Manager in the first test e) 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 Project Manager 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 the steel bars or trestle The vibrator equipments attach outer surface of formwork are encouraged to use Process of pouring and compacting concrete conform to the requirements specified in section “Concrete and Concrete Structures” f) Concrete curing Methods ang processes of concrete curing conform to the requirements specified in section “Concrete and Concrete Structures” 5/ 22 PHUONG THANH TRANCONSIN – GRBCC JV CIVIL WORKS CONTRACT PACKAGE A1 (KM 65+000-KM81+150)- DA NANG – QUANG NGAI SECTION g) Loading, transporting of concrete unit Concrete units are only allowed to move out of casting area in case of concrete compressive strength for each sample in lift of concrete meets 80% minimum compare with the requirement concrete strength for one unit Concrete units are put up and down carefully They will be transported vertically to avoid impacting, bearing points and direction of reaction when transporting and storing are as same as the last installation stage All concrete units will be marked separate and permanent to write clearly type of concrete unit and date of concrete 4.3 Construction of pipe culvert, box culvert and underpass box culvert at the site a) Construction plan and organization The positions of box culverts are for construction of service road; the service road contractor shall carry out construction of entire culvert length At the culvert positions that the service road or pipe culvert can not be constructed, the contractor shall ensure transport by construction of 1/2 the lower culvert first After that, the remained 1/2 culvert in the lower section shall be constructed; these culvert shall be strengthened and opened to its edges by disposed stone or gravel aggregate foundation The service road shall be large enough for directionally safe traffic movement The service road shall be arranged with sufficient signal posts, signal plate, lighting (at night) with traffic control staffs at ends continually during construction period Horizontal drainage culvert shall be arranged temporarily for not affecting the culvert construction activities as well as the existing discharge flow of the road, residential area and irrigational activities b) Excavation of culvert trench Excavation of culvert trenches will execute conform to the requirements specified in section “Excavation and backfill for structure” Construction method and construction order as follows: - Located the centre of culver, scope of trenches as Design Drawings; - Removal of old structures (if any); - Excavation of trenches by excavator, and using man-power for completing trenches Transporting waste material to regulated area - Excavation of trenches with enough large (500 mm minimum from road margin which around the culvert) in order to execute body culvert and embank both sides of culvert Slope of trenches will be executed comply with stability of trenches’s geology - Constructing culvert at the location where water flows frequently will be use cofferdam in method of constructing trenches It will be needed to 6/ 22 PHUONG THANH TRANCONSIN – GRBCC JV CIVIL WORKS CONTRACT PACKAGE A1 (KM 65+000-KM81+150)- DA NANG – QUANG NGAI SECTION construct a small ditch system around inlet to collection water and use pump to pump water out of trenches - When excavating to the trenches bottom, if the weak geological layer is found, the contractor shall inform the Engineer for on-time solution to keep progress - If the soil in the trenches is mixed with quarry stone then the over elevated excavated area shall be backfilled by materials of little deformation under pressure as sand, gravel sand or concrete with the same mark with the trenches and shall be in compact with the foundation The material type and compact requirements shall be in accordance with regulated design documents or with the instructions from the Engineer - Structures of blinding stone and concrete of culvert foundation will be only allowed install when trenches be executed as Design Drawings, be accepted by Project Manager c) Instalation of precast units The Contractor shall lay reinforced concrete cradles and pipes carefully The hubs or grooved ends shall be up grade The spigots or tongued ends shall be fully entered into the adjacent hub or groove and be true to the required lines and grades Before laying succeeding sections of reinforced concrete pipe which not require cambering, the Contractor shall plaster the lower half of the hub of the preceding sections on the inside with Portland cement mortar The mortar shall be sufficiently thick to bring the inner surface of the abutting pipes flush and even The Contractor shall plaster the upper half of the spigot of the succeeding pipe with mortar at the same time All Pipe or Box Culverts shall be laid and fitted together such that the joint sealant forms 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 sealant are at the top of the Pipe or the Box Culverts After laying the reinforced concrete pipe, the Contractor shall fill the remainder of the joint with sufficient mortar to form a bead around the joint The Contractor shall wipe the inside of the joint and finish it to a smooth and even surface The mortar on the outside shall be cured and remain damp for two days or until the Engineer allows backfilling to proceed d) Culvert Headwalls, Inlets, and Outlets Unless otherwise shown on the Drawings, the Contractor shall construct all culvert aprons, wing-walls, and headwalls using reinforced concrete of the class indicated on the Drawings and in accordance with requirements and 7/ 22 PHUONG THANH TRANCONSIN – GRBCC JV CIVIL WORKS CONTRACT PACKAGE A1 (KM 65+000-KM81+150)- DA NANG – QUANG NGAI SECTION provisions of section “Concrete and Concrete Structures” Scour protection works will normally be mortared rip-rap unless indicated in the Drawings 4.4 Construction of in-situ box culvert and in-situ underpass box culvert After constructing culvert trenches, Work items for executing in-situ box culvert and underpass box culvert comply with order as follows: - Spreading blinding stone for culvert foundation; - Construction of bedding stone and foundation lean concrete; - Installation of reinforced steel, pouring concrete for bottom slab of body box culvert; - Installation of reinforced steel, pouring concrete for bodywall and face slab of culvert; - Execution of headwalls, wingwalls, structure of inlets, outlets - Execution of mortar stone structure, reinforcing slope of headculvert, reinforcing to unti – erosion of culvert downstream - Installation of over slab when filling soil to design elevation All works for executiong concrete, reinforced steel, formwork conform to the requirements 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 or rebars shall be laid on the skids; the cement skids have the similar thickness to the protection 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 the reinforcement density but not over 1m from a skidding place The salvage shall not be used 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 during concrete casting The pre-erected parts 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 in cooperation with manpower and closely connected by bolts It shall be noted to erect the scaffolding and bearing braces to ensure the stability of the platform during concrete casting The cleats shall be arranged for easy disassembling of the scaffolding and platform when the concrete reaches the allowed strength 8/ 22 PHUONG THANH TRANCONSIN – GRBCC JV CIVIL WORKS CONTRACT PACKAGE A1 (KM 65+000-KM81+150)- DA NANG – QUANG NGAI SECTION Concrete casting and vibration: Equipments and materials as well as manpower shall be checked before concrete casting The materials shall be sufficient for continuous concrete casting and the concrete batching machine shall operate well - Concrete casting-in-situ shall be done by batching machine and crane Concrete 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 - During casting, sample shall be taken to test the slump of the concrete for adjustment as in the design Sample shall be casted for later test The aggregate measurement system shall also be checked to ensure the design batching ratio for concrete - Concrete transference chute shall not be over dip, the free falling height of the concrete shall not be overt 1m because of making concrete stratification - The upper concrete layer shall be casted and vibrated before the concrete layer below starts to freeze - Concrete shall be well vibrated right after casted - If the needle vibrator and plate vibrator are used, then the maximum thickness of the concrete layer shall be as follows: + If the needle vibrator is used, the concrete layer thickness shall be by 1.25 of the effective length of the needle arm + If the plate vibrator is used, the concrete layer thickness shall be 12cm for the structure with much reinforcement, or shall be 25cm for the non-reinforcement structure + The distance for needling the vibrator shall not exceed 1.5 time of the effective radius of the vibrator The vibrator shall not penetrate to the lower concrete layer casted before, if this layer is freezing - If the plate vibrator is used, then the vibrating marks shall overlapped by - 5cm Vibrating through the reinforcement shall not be done - Concrete casting shall be done continuously until part by part of the construction works is completed Concrete maintenance: After concrete casting no later than 10 -12 hours in winter or - hours in summer, watering shall be done and the concrete surface shall be covered in days and nights; if the temperature exceeds 150C, then watering shall be done in the first days and nights: in daytime, watering shall be done after every hours and in 9/ 22 PHUONG THANH TRANCONSIN – GRBCC JV CIVIL WORKS CONTRACT PACKAGE A1 (KM 65+000-KM81+150)- DA NANG – QUANG NGAI SECTION night time, watering shall be done for – times, then at least times of watering 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 of minimum 25kg/cm2 For the strength-resistant scaffolding and platform, concrete shall reach 70% of the designed strength then the platform can be disassembled The platform disassemble shall be done carefully for not creating the thrust to the concrete structure Before and after strength-resistant platform disassemble, the slump of the deformation area and structure shall be measured 4.5 Backfill Backfill of foundation pit and fill material both side of culvert comply with the requirements specified in Section “Excavation and backfill for structure” The Contractor shall not backfill any pipe until the Engineer inspects and approves the site conditions The Contractor shall backfill and compact the soil around and over the reinforced concrete culvert pipes in accordance with the requirements specified in Section “Embankment Construction” and “Excavation and backfill for structures” The Contractor shall take the fill to a minimum height of 500 mm above the top of the pipe Unless in a trench, the fill shall extend for a minimum distance of one and a half diameters from the centerline of the pipe on each side of the pipe The Contractor shall take special care to compact the backfill under the haunches of the pipe properly The backfill shall be brought up evenly on both sides of the haunches for the entire pipe length Heavy earth moving and compacting equipment shall not operate closer than 1.5 meters from the culvert until the cover above the pipe is at least 500 mm Light weight equipment may operate within the limitation mentioned above provided the backfill is placed and compacted at least 300 mm above the top of the pipe Notwithstanding these conditions, the Contractor shall be responsible for and shall rectify any damage resulting from such operations 4.6 Cleaning Culverts The Contractor shall clean all culverts until they are free of loose debris, soil, and all foreign material The Contractor shall keep the culverts clean and maintain them in an operating condition throughout the Contract Period The Contractor shall only permit water to flow through the cleaned culvert after the Engineer inspects and approves the culvert 4.7 Quality assurance method a) Pipe culvert quality assurance method Pipe culvert shall be laid at right positions, straight to the longitudinal section of the pipe culvert and suitable to the natural flow The inner and outer surfaces of the pipe culvert shall be flat and smooth with no crack, porosity or roughness 10/ 22 PHUONG THANH TRANCONSIN – GRBCC JV CIVIL WORKS CONTRACT PACKAGE A1 (KM 65+000-KM81+150)- DA NANG – QUANG NGAI SECTION Allowed error of major dimensions of the pipe culvert is regulated in the standard 22 TCN 159 - 86 Limited discrepancy values Component Length (mm) Diameter (mm) Curve (mm) Thickness (mm) Platform ±5 ± 2,5 ±5 - Reinforcement ±5 +2 - - -10; +5 ± 10 - ±5 Pipe culvert body The following parameters are noted in detail on each component of the precasted concrete pipe culvert body: - Type of pipe culvert and inner diameter; - Date of casting; - Lot number of products; - Product testing results; - Name and code of typical drawings of applied pipe culvert components - Pipe culvert with one of the following features shall be discarded: + Serious cracks or crazes; + Defects due to unsuitable mixture ratio and under-required batching and vibration; + Porosity or breaking; reinforcement sticks out; + Reinforcement sticks out or serious displacement of reinforcement (checking is carried out by ruler to measure the concrete layer); + Pipe culvert opening is damaged or cracked, broken (these damages inconvenience the connection joint construction) Checking the elevation, dimension and geological conditions of foundation bedding: Before culvert foundation construction, the foundation pit is checked with elevation, dimension and geological conditions of foundation bedding by the SC The construction of the next parts of the box culvert shall only be carried out with the approval in writing of the Supervision Consultant Culvert shall be laid at the easy water discharge position; after laid, culvert shall be straight, at right elevation and gradient as designed Error of culvert bedding elevation is ±10mm, assuring the uniformity of the outlet and inlet of the culvert The outlet and inlet of the culvert shall be strengthened; the absorption basin shall be at designed dimension The tightness of embanked soil layer in the foundation pit, culvert opening and culvert top shall be checked regularly before carrying out the next layers 11/ 22 PHUONG THANH TRANCONSIN – GRBCC JV CIVIL WORKS CONTRACT PACKAGE A1 (KM 65+000-KM81+150)- DA NANG – QUANG NGAI SECTION To ensure the construction quality, during construction period, the contractor shall strictly obey the requirements for technique and construction technology, especially following issues: - The construction materials shall be in right types of the quality tested materials, which were approved by the SC and the employer - The semi-finished materials shall be from the right sources, with full standards meeting the requirements in the design documents and under procedures - The concrete and grout measurement and batching systems shall be ensured with designed ratio Casted concrete shall be ensured with slump, strength… The concrete slump shall be checked right at site to adjust the water volume for suitability to the design ration b) Box culvert and retaining wall quality assurance method Besides the requirements for pipe culvert quality assurance, the contractor shall have following methods: - Box culvert shall be laid at easy water discharge position; after laid, culvert shall be straight, at right elevation and gradient as designed Error of culvert bedding elevation is ±10mm, -20mm assuring the uniformity of the outlet and inlet of the culvert - Regular measurement and check shall be carried out to ensure that the construction works is at right position, elevation and geometric dimension The discrepancies of elevation and position in culvert construction are absolutely forbidden Thus accurate measurement and benchmarking shall be carried out prior to construction implementation During construction, supervision and monitoring are required to ensure the geometric dimension of culvert foundation, culvert centerline, culvert body, headwall, wing wall… - Concrete casting for foundation, wall body and other structures shall be continuously carried out to ensure the monolithism The construction load impacts and concrete vibration shall be finished before the concrete mixes - Steel platform shall be used to ensure the flat surface with full rigidness and no deformation The bracing and scaffolding system shall be checked closely to ensure the stability for concrete casting Allowed error in platform acceptance: NO Allowed error (mm) Content for checking Deflection of platform centerline with the wall foundation 25 Deflection of platform centerline of wall body and wing wall 10 Error of dimensions of cross-sections of the foundation platform 50 Error of dimensions of cross-sections of the body platform 20 Error compared to the vertical line (or designed skew) of relative platform surfaces 12/ 22 PHUONG THANH TRANCONSIN – GRBCC JV CIVIL WORKS CONTRACT PACKAGE A1 (KM 65+000-KM81+150)- DA NANG – QUANG NGAI SECTION - For > 1m height - For the entire height: + Of the foundation + Of the abutment wall and wing wall 20 10 Partial concavo-convex of the platform checking by ruler 2m - Soil embankment at sides of the culvert shall be carried out manually to avoid breaking the culvert The embankment materials shall be the soil with suitable physic-mechanical indicators Over thick embankment shall not be carried out to ensure the compaction tightness - Measurement and checking of positions and dimensions shall be carried out regularly to control and adjust the discrepancies in construction and to avoid accumulative errors of position and dimension Error of dimensions and positions of culvert concrete structure shall meet the requirements in the Table below: NO Content for checking Allowed error (mm) Error of the exposed and horizontal surfaces, deflecting than the design position: - For every 1m of the surface - For the entire surface 20 Error of elevation and other dimensions - The contractor shall establish a test team at site to regularly test the granular composition, density, site compactness… of the embanked soil, broken stone for construction work quality assurance - Concrete slump at site shall be checked and the sample shall be casted for strength testing following right specifications and norms If the test results meet the requirement and approved by the SC, the contractor can implement the next work items II DETAIL CONSTRUCTION METHOD FOR SIDE DRAINAGE AND SLOPE DRAINAGE Description This work shall consist of furnishing, constructing and/or installing side drainage types of structures built, slope drainage types of structures built in conformance with the Contract Drawings Included are such items as trapezium shaped, rectangle shaped, and bench ditch, stepped drop, ditch at top of slope Materials requirement 13/ 22 PHUONG THANH TRANCONSIN – GRBCC JV CIVIL WORKS CONTRACT PACKAGE A1 (KM 65+000-KM81+150)- DA NANG – QUANG NGAI SECTION To construct roadside Ditches using mortared stonework, concrete, reinforced concrete, 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 of materials he intends to use for the construction of Ditches Bedding: - Granular material for bedding shall be in accordance with Paragraph 4.2, Table of Vietnamese Standard TCVN 7570 - 2006 and subject to the approval of the Engineer - Lean concrete for bedding shall be in accordance with the requirements of Specification Section “Concrete and Concrete Structures” Mortared Stone: - Mortared stonework shall conform with the requirements of Specification Section “Mortared Stonework” Concrete: - Precast and cast insitu concrete for side drainage structures, shall conform to the requirements of section“Concrete and concrete structure” Reinforcing Steel for concrete: - All reinforcing steel shall conform with the requirements specified in Specification Section “Reinforcing Steel” Rip-rap: - Rip-rap for side drainage structures shall conform to the requirements of section “Mortared Stonework” Method of Construction 3.1 Site Preparation Drainage excavation is combined with embankment excavation, and then the drainage form shall be fixed manually Drainage before construction shall be cut off with abundant soil, the jumping compactor shall be used to compact the drainage bedding, assuring the gradient, compactness and the flat of the slope and drainage groove in conformity with the design 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” 14/ 22 PHUONG THANH TRANCONSIN – GRBCC JV CIVIL WORKS CONTRACT PACKAGE A1 (KM 65+000-KM81+150)- DA NANG – QUANG NGAI SECTION 3.2 Construction side drainage concrete Construction side drainage concrete, shall conform to the requirements of “Concrete and concrete structure” Basic construction order as follows: - Construction of ditch bottom slab; - Installation of formwork of ditch border, pouring concrete as design; - Removal of formwork, completing the ditch as design - Supplementary embankment of ditch structure (if any) - Clearing and removing of waste material 3.3 Construction bench ditch, ditch at top of slope Construction bench ditch concrete, ditch at top of slope concrete, shall conform to the requirements of “Concrete and concrete structure” Supplying concrete to construction location, transporting to bench ditch, top ditch by capstan system or hoist Basic construction order as follows: - Constructing of ditch bottom slab; - Installation of formwork of ditch border, pouring concrete ditch as design; - Removal of formwork, completing the ditch as design - Supplementary embankment of ditch structure (if any) - Clearing and removing of waste material 3.4 Construction stepped drop by stone masonry Rip-rap and mortar for stepped drop structures shall conform to the requirements of section “Mortared Stonework” Supplying riprap and grouting (mortar) to construction location by capstan system or hoist Preparation for foundation pit of stepped drop accordance with design document Executing mortar stone of stepped drop in process from low to upper All joints of inlets from bench ditches, top ditches, side ditchs, executing carefully the inlet of culvert and comply with Design Drawings Ensuring in good operation Tolerances, Rectifying and Maintenance 4.1 Dimensional Tolerances Grades of Ditch inverts against those specified or ±5 mm at any point approved 15/ 22 PHUONG THANH TRANCONSIN – GRBCC JV CIVIL WORKS CONTRACT PACKAGE A1 (KM 65+000-KM81+150)- DA NANG – QUANG NGAI SECTION Ditches alignments and the shape of cross sections as ±2 cm at any point specified on the Drawings 4.2 Rectifying Unsatisfactory Work All materials and workmanship used in the construction of Ditches shall be subject to the inspection and approval of the Engineer Where appropriate the Engineer will issue instructions for any remedial work found necessary as a result of unsatisfactory work by the Contractor The Works will not be approved until such time as they have been completed to the satisfaction of the Engineer Remedial work may include but not be limited to: - Repetition of survey work defining existing or constructed surface profiles as often as necessary to obtain an accurate record of the physical conditions; - Additional excavation or fill, which could include backfilling new work and re-excavating it to the specified dimensions, lines, and grades, and - Repairing or replacing defective mortared stonework or concrete work No additional payment or extension to the Time for Completion granted shall be made for the extra work or quantities expended for rectification work 4.3 Maintenance of Accepted Work The Contractor shall be responsible for the routine maintenance, cleaning and care of the Ditches until the issue of the Taking-Over Certificate III DETAIL CONSTRUCTION METHOD FOR IMPROVEMENT AND RELOCATION OF EXISTING IRRIGATION CHANNELS Description Channels shall be constructed in accordance with the Drawings for the improvement and/or relocation of Existing Irrigation Channels affected by the Works Such work shall include excavation of channels to the depths and shapes required, including the placing and shaping of excavated materials along the sides as shown on the Drawings The work for channel improvement and/or relocation shall include; the removal of existing dikes, connection with the existing channels, filling and flattening of closed channel sections and any other incidental work to complete the Works Materials requirement 2.1 Materials: 16/ 22 PHUONG THANH TRANCONSIN – GRBCC JV CIVIL WORKS CONTRACT PACKAGE A1 (KM 65+000-KM81+150)- DA NANG – QUANG NGAI SECTION The materials for improvement and/or relocation of Existing Irrigation Channels and/or structures, shall conform with the material requirements specified in respective Specification Sections for the Existing Irrigation Channels and/or structures to be improved In the event that the Existing Irrigation Channels and/or structures are of the types that are not covered by this Specification Section the material requirements shall be as stated in the Standards for the materials in ASTM or AASHTO, or as determined by the Engineer 2.2 Submittals: Work Scheduling: A detailed work schedule for each irrigation channel and/or related structures shall be submitted by the Contractor indicating all the construction methods and procedures, including all the necessary measures to control the water and not affect the operation of the existing irrigation and/or waterway systems The Contractor shall not begin the improvement and/or relocation of the irrigation channels and/or the related structures without the Engineer’s approval on the schedules and construction methods proposed by the Contractor The Contractor shall schedule all of the required construction works to ensure the improvement and/or relocation of the irrigation channels and/or the related structures can move smoothly The following shall be considered in the schedule: - Temporary Works shall be in place and operating before beginning embankment Works or as directed by the Engineer - The Contractor shall first shape the Irrigation Channel works to the approved cross sections - The last activity in the schedule shall comprise the final shaping as well as any repairs or damages that may have occurred during construction after completing all other immediately adjacent or interfacing Works Method of Construction 3.1 Preservation of Existing Waterways Existing waterways (which include irrigation channels, drainages, streams and rivers) shall not be disturbed without the permission of the Local People’s Committee and/or Irrigation Company and/or other Companies that are is responsible for their operation and maintenance For waterway realignments, whether temporary or permanent, the Contractor shall maintain the existing channel invert levels as much as possible Realigned waterways shall be located so that their expected flows will not cause detrimental scour or erosion of the Works or nearby properties 17/ 22 PHUONG THANH TRANCONSIN – GRBCC JV CIVIL WORKS CONTRACT PACKAGE A1 (KM 65+000-KM81+150)- DA NANG – QUANG NGAI SECTION The Contractor shall be responsible for maintaining the design flows and water levels in all temporarily relocated waterways (which include irrigation channels, drainages, streams and rivers) as far as possible up to the issue of the Taking-Over Certificate The Contractor shall also be responsible for any additional pumping or other related works for maintaining these irrigation and other facilities Where embankment stabilisation or other Permanent Works of the Contract will unavoidably block or partially block any existing waterways these waterways shall be relocated to ensure that unrestricted flows can pass the works at all usual supply and drainage rates and will not affect the existing flood control levels If the Contractor cannot avoid excavating or dredging in any existing waterways for proper execution of the Works he shall backfill all such excavations to the original ground elevations and shapes with materials approved by the Engineer after completing construction The Contractor shall remove materials deposited within the waterway area resulting from foundation excavation, constructing cofferdams or other related works following construction Finished grades on realigned (or relocated) irrigation channel inverts shall not vary by more than the dimensional tolerances provided in subsection of this Specification Section The finish shall be sufficiently smooth and uniform to ensure the free flow of water without ponding during periods of low flow The alignment and the shape of cross sections for the realigned (or relocated) Irrigation Channels shall not vary from those specified in the Drawings by more than the dimensional tolerances provided in subsection of Specification Section The Contractor shall notify the Engineer after completing Irrigation Channel excavation No lining works shall begin until the Engineer approves the formations 3.2 Preservation of Water Control Structures The Contractor shall not disturb existing water control structures adjacent to the works of this Contract without the approval of the Local Authorities These structures shall include existing culverts, canal inlets, regulators, gates, pumping stations, etc Water regulation structures for irrigation shall not be disturbed without the permission of the Local Authorities that are responsible for their operation and maintenance 3.3 Concrete Lined Irrigation Channels Relocation of Existing Irrigation Channels, which are concrete lined shall conform with the requirements of this Specification Section and Specification Section “Concrete and Concrete Structures” Such work shall include; excavation of the channels to the depths and shapes required, the deposition and shaping of excavated materials along 18/ 22 PHUONG THANH TRANCONSIN – GRBCC JV CIVIL WORKS CONTRACT PACKAGE A1 (KM 65+000-KM81+150)- DA NANG – QUANG NGAI SECTION the sides, bedding, construction of the new channels and their respective connections with the existing irrigation systems 3.4 Earth Lined Irrigation Channels Relocation of the existing channels which are earth lined shall conform with the requirements of this Specification Section, Specification Section “Borrow Material” and Specification Section “Embankment” Such work shall include excavation of the channels to the depths and shapes required, the deposition and shaping of excavated materials along the sides, bedding, construction of the new channels and their respective connections with the existing irrigation systems 3.5 Dimensional Tolerances Items Finished grades on realigned (or relocated) Irrigation Channel inverts Tolerances ±1 cm from the existing invert levels Alignment and shape of cross ±5 cm (at any points) from those sections for realigned (or relocated) specified in the Drawings 19/ 22 PHUONG THANH TRANCONSIN – GRBCC JV CIVIL WORKS CONTRACT PACKAGE A1 (KM 65+000-KM81+150)- DA NANG – QUANG NGAI SECTION IV DETAIL CONSTRUCTION METHOD FOR CATCH BASINS, MANHOLES, INLETS, AND OUTLETS Description This Specification Section prescribes the requirements for the construction of Catch Basins, Manholes, Inlets and Outlets to culverts Requirement Materials The Contractor shall submit to the Engineer for his approval details and samples of materials he intends to use for the construction of Catch Basins, Manholes, Inlets and Outlets to culverts and ditches included in this Specification Section 2.1 Bedding Fine sand fill/bedding shall be black sand complying with the requirements of Table of Vietnamese Standard TCVN 7570-2006 with a fineness modulus of 0.7 to 2.0 Organic and other impurities shall be in accordance with Table of Vietnamese Standard TCVN 7570-2006 as follows: - Clay and balled impurities shall be less than 0.5% - Muds and dirt shall be less than 10% It will not be necessary to determine the alkali reactivity or the chloride content of the sand for this use Sand shall be sampled and tested in accordance with Vietnamese Standard TCVN 7572-2006 (Aggregates for concrete and mortar - Test methods) Granular material for bedding shall be in accordance with Paragraph 4.2, Table of Vietnamese Standard TCVN 7570-2006 and subject to the approval of the Engineer Lean concrete for bedding shall be conforming with the requirements of Specification Section “Concrete and Concrete Structures” 2.2 Concrete Concrete used for all structural work described in this Specification section shall conform to the requirements specified in section “Concrete and Concrete Structures” 2.3 Reinforcing Steel for Concrete All reinforcing steel used in the works shall conform to the requirements specified in section, “Reinforcing Steel and steel works” 2.4 Mortared stone Mortared stone and mortar used in the works shall conform to the requirements specified in section, “Mortared stone” 20/ 22 PHUONG THANH TRANCONSIN – GRBCC JV CIVIL WORKS CONTRACT PACKAGE A1 (KM 65+000-KM81+150)- DA NANG – QUANG NGAI SECTION 2.5 Steelwork Steelwork items shall comply with the requirements of Vietnamese Standard 22TCN288-2002 and shall be galvanised in accordance with AASHTO M232 2.6 Brickwork Brickwork shall conform with the requirements of Specification Section “Brick Masonry” 2.7 Mortar Mortar for joints or other works shall only be used if required by the Engineer, or so indicated on the Drawings If or when required mortar shall conform with the requirements of Specification Section “Cement Mortar” 2.8 Steel Grating Steel grating covers for the Catch Basin for Median as indicated on the Drawings shall comply with the requirements of AS 3679 Grade 250, BS 4360 Grade 43A or ASTM A36 2.9 Porous Backfill or Filter Material In case of requirement in drawings, Porous Backfill or Filter Material shall be in accordance with the provisions of section “Porous drainage and Backfill” or as directed by the Engineer 2.5 Backfill Filling material used in the works shall conform to the requirements specified in section “Excavation and Backfill for structure” Detail construction method for catch basins, manholes, inlets, and outlets 3.1 Shop Drawings and Schedule a Shop Drawings: The Contractor shall prepare shop drawings and method statements showing his proposed construction details for the Catch Basins, Manholes, Inlets and Outlets to culverts and ditches indicated on the Drawings or as directed by the Engineer Shop drawings and method statements shall be submitted to the Engineer for his approval prior to the start of the any construction works, including the start of any precast works b Work Scheduling: Construction of the Catch Basins, Manholes, Inlets and Outlets to culverts and ditches shall not begin until the Engineer has approved the Contractor’s shop drawings and method statements The Contractor shall allow sufficient time in his programme for the submission and approval of 21/ 22 PHUONG THANH TRANCONSIN – GRBCC JV CIVIL WORKS CONTRACT PACKAGE A1 (KM 65+000-KM81+150)- DA NANG – QUANG NGAI SECTION his shop drawings and method statements and for any revision and resubmission of such documents that may be required to incorporate the comments of the Engineer c Site Preparation The Contractor shall carry out any excavation that may be required for Catch Basins, Manholes, Inlets and Outlets in accordance with the requirements of Specification Section 03200 Structural Excavation The Contractor shall be responsible for all dewatering and temporary support works for the excavations and all other necessary temporary works that may be required during construction 3.2 Delivery, Storage and Handling Materials delivered to Site shall be inspected for damage, unloaded, and stored with minimum handling Any damaged materials shall be rejected and replaced at the Contractor’s expense 3.3 Connections Culvert pipes or ditch sections shall be placed or cast and properly bedded before being cast into or built into Catch Basins, Manholes or Inlet and Outlet structures 3.4 Manhole and Catch Basin Covers, and Frames Covers (R.C or Steel Grating) to manholes and catch basins shall be fabricated, precast or prefabricated, supplied and installed complete with steel frames and lifting points as indicated on the Drawings 22/ 22 PHUONG THANH TRANCONSIN – GRBCC JV ... CONSTRUCTION METHOD FOR SIDE DRAINAGE AND SLOPE DRAINAGE Description This work shall consist of furnishing, constructing and/or installing side drainage types of structures built, slope drainage types of... TCVN 9116:2012: Pre-cast RC box culvert Technical requirements TCVN 9113:2012: Drainage reinforced concrete pipe TCVN 44 53 – 1995: Monolithic concrete structure construction and acceptance – Norm... CONTRACT PACKAGE A1 (KM 65+000-KM81+150)- DA NANG – QUANG NGAI SECTION Granular material for bedding shall be in accordance with Paragraph 4. 2, Table of Vietnamese Standard TCVN 7570-2 006 and subject