7 1 ok CW2C BORED PILES

CMDRCP / CW2C PACKAGE CW2C KM 18+200 – KM 23+450 CONSTRUCTION METHOD STATEMENT FOR BORED PILES 1/ 15 PHUONG THANH - QUYET TIEN - ANH GIANG – THANG LOI JOINT VENTURE CMDRCP / CW2C PACKAGE CW2C KM 18+200 – KM 23+450 TABLE OF CONTENTS I MATERIALS FOR PILING II REBAR WORKS III CONSTRUCTION OF BORED PILES 2/ 15 PHUONG THANH - QUYET TIEN - ANH GIANG – THANG LOI JOINT VENTURE CMDRCP / CW2C PACKAGE CW2C KM 18+200 – KM 23+450 Reference standards: The following Standards in their latest edition shall be particularly applied to the works covered by this Specification ASTM A36 Carbon Structural Steel OCMA DFCP4 Drilling Fluid Materials Bentonite Oil Companies Materials Association (OCMA) API S13A Specification for Oil Well Drilling Fluid Materials (APIS: American Petroleum Institute Standard) TCXDVN 326-04 or 22TCN 257-2000 Construction and Measurement of Bored Piles I MATERIALS FOR PILING CONCRETE Bored piles shall be constructed in accordance with the details shown on the drawings using the class of concrete noted on the drawings and in accordance with Specification - Concrete and Concrete Structures Concrete shall be mixed and placed in accordance with the applicable provisions of Specification - Concrete and Concrete Structures REINFORCING STEEL Reinforcement shall comply with the provisions of Specification - Reinforcing Steel TEMPORARY CASINGS Bored piles shall be excavated with a temporary steel casing through water and upper soil layers which might otherwise collapse Temporary casings shall be free from significant distortion They shall have a uniform cross-section throughout each continuous length During concreting they shall be free from internal projections and encrusted concrete which might prevent the proper formation of piles PERMANENT CASINGS Permanent casings required for construction purposes shall be of the thickness and length proposed by the Contractor, and shall be of steel grade ASTM A36 unless otherwise approved Steel casings shall be furnished in appropriate lengths approved by the Engineer The casings shall be handled and stored in a manner that prevents buckling and other deformation and the accumulation of dirt, oil and paint When placed in the work they shall be free from dirt, oil, grease, paint, millscale and loose or thick rust BENTONITE AND BENTONITE SLURRY (DRILLING FLUID) (a) Supply Immediately prior to mixing Bentonite shall be in accordance with Specification DFCP4 of the Oil Companies Materials Association (Drilling Fluid Materials Bentonite), or the American Petroleum Institute Standard 13A (b) Mixing 3/ 15 PHUONG THANH - QUYET TIEN - ANH GIANG – THANG LOI JOINT VENTURE CMDRCP / CW2C PACKAGE CW2C KM 18+200 – KM 23+450 Bentonite shall be mixed thoroughly with clean fresh water to make a suspension which will maintain the stability of the pile excavation for the period necessary to place concrete and complete construction Where chemically contaminated groundwater occurs, special precautions shall be taken to modify the bentonite in all respects for the construction of piles II REBAR WORKS All reinforcement steel shall comply with the requirements of Specification Section 07500 “ Reinforcing steel ” III CONSTRUCTION OF BORED PILES Preparation works Construction equipment includes : Drilling equipment: is a self-propelled crane for craning casing, equipment and erecting the drilling machine Drilling equipment includes of grab buckets as mechanical or hydraulic dredging buckets Mixing equipment, tanks and bentonite pumps Vibrating hammer is enough capacity for lowing the casing into the hard ground Cleaning equipment: betonite pumps, compressors 10m3/minutes Other construction equipment such as tremie pipes, concrete vehicles, mix truct, welding equipment, etc List of main equipment Uni Num ts ber piling set 01 piling set 01 Barge ≥ 250T nos 01 Barge ≥ 30T nos 01 Item of work Reverse circulation Remark equipment D1,5m Reverse circulation equipment D1,0m Crawler or Moblie Cranes ≥50T nos 02 Crawler or Mobile Cranes ≥25T nos 04 Excavator with bucket capacity ≥ nos 04 0.7m3 4/ 15 PHUONG THANH - QUYET TIEN - ANH GIANG – THANG LOI JOINT VENTURE CMDRCP / CW2C PACKAGE CW2C KM 18+200 – KM 23+450 Item of work Uni Num ts ber nos Front Loader ≥2,4m3 02 Mixer of bentonite nos 04 Vibration hammer nos 03 set 04 Bentonite Pump nos 04 Tank for betonite nos 06 Pipe tremie set 01 Test set of betonite nos 02 Air Compressor nos 04 Testing set of concrete nos 02 Concrete Batching Plant 60m3/h nos 02 Truck for concrete nos 06 Main and standby generator nos 02 Concete pump nos 02 Concrete pipe m 600m Set of pipe for cleaning bored set 03 Total Station nos 02 Surveyor’s Level nos 02 Cutting and bending machine nos 04 Sand separation system for Remark betonite fuid hole Construction site preparation For the abutment, pier on land: remove organic soil and leveling to create construction site 5/ 15 PHUONG THANH - QUYET TIEN - ANH GIANG – THANG LOI JOINT VENTURE CMDRCP / CW2C PACKAGE CW2C KM 18+200 – KM 23+450 For the pier next to river side: Driving sheet pile system, leveling to create construction site The main purpose of preparing site plan is creating space for the installation and operation of drilling equipment and construction of bored piles Positioning the pile centre by Total Sation and marker is made by wooden piles to avoid the lost during construction process, Drawing a circle with diameter the same with casing on the ground and take this ring to locate the casing when lowering Pile center under water shall be located based on the casing and positioning frame Mobilization of material, equipment for bored pile (installation of drilling equipment, crane, casing, positioning pile, air compressor, manufacture of rebar for pile) Checking the operation of equipment, concrete supply, water and power Mixing of bentonite Bentonite is mixed with cleaned water to create the slurry, maintain the stability of the drilling work in the concrete placing and completion of execution The temperature of the water used for mixing Bentonite is not less than degrees C Bentonite grout is mixed and operation in a specialized equipment in a closed process includes all stages of mixing, filtering, pumping to drilling holes and gather mortar for reusing Bentonite is strictly in accordance with the technical standards by Contractor Benonite mixing ratio dry / water is adjusted according to actual geological drilling Contractor shall conduct the tests in accordance with bentonite specification before commencement of work The contractor will propose test methods, sampling procedures, inspection frequency and bentonite grout and submit to the Engineer Betonite's certificate Contractor’s site lab is sufficiently equipped with equipment to examine the density, viscosity, pH, shear force of the bentonite mixture to deploy test in the construction process The tests and inspections must be taken regularly for bentonite Property to be Range of results at 20°C Test method Less than 1.10g/ml Mud density balance measured Density (ASTMD4380) Viscosity 6/ 15 18-45 seconds Marsh cone (ASTM PHUONG THANH - QUYET TIEN - ANH GIANG – THANG LOI JOINT VENTURE CMDRCP / CW2C PACKAGE CW2C KM 18+200 – KM 23+450 D6910) Shear strength (10 minute gel strength) 1.4-10 N/m2 or 4-40 N/m2 Shearometer Sand content