Hanoi – Hochiminh city railway line                        Do Vang Bridge’s construction bridges safety improvement projec...
Hanoi – Hochiminh city railway line                        Do Vang Bridge’s construction bridges safety improvement projec...
Hanoi – Hochiminh city railway line                         Do Vang Bridge’s construction bridges safety improvement proje...
Hanoi – Hochiminh city railway line                          Do Vang Bridge’s construction bridges safety improvement proj...
Hanoi – Hochiminh city railway line                         Do Vang Bridge’s construction bridges safety improvement proje...
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05.chapter iii

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05.chapter iii

  1. 1. Hanoi – Hochiminh city railway line Do Vang Bridge’s construction bridges safety improvement project technology of beam casted onscaffolding CHAPTER III: MATERIAL REGULATIONSI. GENERAL All meterials for box girder and other items shall be in accordance with theSpecification of Project and shall be taken test sample according to quality controllingplan. Sample for test and construction shall be supervised and approved by Engineer. Just only use materials which are approved by Engineer according to Specificationand Quality Controlling Plan. Materials which not satisfy the above requirement shall be rejected and removed outfrom Site. Approved material source shall be use for the entire Project. For a new source, it isnecessary to take sample and be approved by Engineer in accordance with Specificationif the source has any change. During placing concrete for continuously voided slab beam segments, all materialsmust be enough for mixing and providing not interupted.II. MATERIALS1. Reinforcement a. High strength reinforcement High strength strand with low relaxation shall be in accordance with ASTM416-99standard of Grade 270 or equivalent, with the main parameters as follows: + Grade 270, low relaxation. + Breaking strength: fpu = 1860MPa + Yield limit: fpy = 1674 MPa + Modulus of elasticity: 195000 MPa + Relaxation after 1000h at 20°C ≤ 2,5 %. Construction regulations: + High strength strand shall be not welded. 31
  2. 2. Hanoi – Hochiminh city railway line Do Vang Bridge’s construction bridges safety improvement project technology of beam casted onscaffolding + Each coil of cable must have Certificate of Producer. The Certificate shows relative curve between load and elongation, measured area, elastic mudulus for each lot. + High strength cable lots shall be checked before testing, taken sample to test for each lot or taken a group sample for every 20T. + In any case, jacking force for each strand is not over 0, 80 of minimum ultimate strength of cable. + Jack must be suitable with presstressed tendon about structure and tensioning force. Jack and gauge shall be checked before using. b. Non-prestressed reinforcement The Subcontractor intends to use Viet Y Steel for construction Project. Non-prestressed reinforcement must be in accordance with Specification of Project: JISG 3112 SD3452. Prestressed anchor Pre-stressed anchor must be conformed to 22TCN 267-2000 Standard and thefollowing requirements: + All anchor devices must have enough capacity to keep prestressed cable with a stress not less than 95% of ultimate tensile strength of prestressed cable showed on Certificate of Producer and anchor, cable Test Result. + Anchor shall be checked to ensure type as submitted, geometric dimension, mechanical defect to reject defected anchor.3. Duct The corrugated duct must be appropriate, synchronous with type, grade of prestressedcable and anchor. Duct system shall be airproof, waterproof. Diameter of duct must begreater at least 6mm than nominal diameter of tendon; cross section area must be greater2.5 times than tendon area. The minimum thickness of duct must be in accordance with approved design andinstruction of producer that be agreed by Engineer. 32
  3. 3. Hanoi – Hochiminh city railway line Do Vang Bridge’s construction bridges safety improvement project technology of beam casted onscaffolding4. Concrete The girder concrete is B arccording to Specification of Project. Mix design shall conform to Specifications of Project. Material regulation is as follows: a. Cement Cement is Portland cement corresponding to JIS R5210 or ASTM-C150-98 (TCVNPCB40, TCVN6260-1997) standard. Expiry date and Manufacturer Certificate shall besubmitted before using. Product lots brought into Site must have full bags, components. Bagged cement shall be kept in a temporary depot and used on time since the materialhas been delivered. Bulk cement shall be kept in silo corresponding to manufacturer regulations. b. Fine aggregate: Sand Fine aggregate using for concrete shall be in accordance with JISA 1102 or equivalentstandard. Aggregate shall be kept to avoid segregating or contaminating. The centre of depotmust be prevented from moisture excess. To prevent different-size aggregates from mixing together, make a baffle betweenthem. Only use uncontaminated, non-toxic mud, clean fine aggregate. The fineness modulusmust satisfy the Specification of Project as the following: + Granular composition (according to JISA 1102 standard): Sieve number (mm) Percentage passing by weight 10 100 5 90~100 2.5 80~100 1.2 50~90 0.60 25~65 0.30 10~35 0.15 2~10A 33
  4. 4. Hanoi – Hochiminh city railway line Do Vang Bridge’s construction bridges safety improvement project technology of beam casted onscaffolding The Subcontractor has intention in using Mia Duong, Ha 12 – Bo Trach – QuangBinh coarse sand for concreting works of Project. Aggregate shall be checked with the above requirements before constructing. c. Coarse aggregate: Rock 1x2 Coarse aggregate must respond to JISA 1102 or equivalent. The Subcontractor intends to use stones Len Cut Tai - Quang Trach - Quang Binh forconcreting works of Project. Coarse aggregate size is shown in the below table: Sieve number (mm) Percentage passing by weight 30 100 25 95~100 20 - 15 30~70 10 - 5 0~10 2.5 0~5 d. Water Water for mixing or curing concrete must be fresh water, uncontaminated with oil,saline, acid, sugar, vegetable or other toxic materials. Excluding water approved aspotable water by competent authority, others shall be tested and satisfied AASHTO-T26standard: Water for concrete and mortar. Water/concrete ratio is not over 0.40. Water sources for constructing continuous box girder casted on scaffolding of DoVang Bridge shall be the source using for Sub-structure items of Project. Check pH value at site before placing concrete or test water sample again ifnecessary. e. Admixture Admixture shall meet instructions JISA 6204. 34
  5. 5. Hanoi – Hochiminh city railway line Do Vang Bridge’s construction bridges safety improvement project technology of beam casted onscaffolding Admixture that boots setting speed, increases mobility or retarding admixture, wettingadmixture, v.v… can be use but must be approved by Engineer before constructing. Admixture may be one of the following types: SiKa Viscocrete 3000-10 to be inaccordance with real construction requirements at Site. Admixture not the type as required shall be rejected and removed out of Site. Waterfixed content and admixture shall be put together at mixing plant. Inspector shall check type, maintenance, and ratio of concrete admixture whether asrequired or not.5. Pumped groutGrout made from Pooclang cement, water and admixture are accepted by Engineer.Grout is mixed as follows: Bleeding rate is not over 3% Non-shrinkageSwelling index is not over 10%. But this rate is always smaller than bledding rate afteratomizing up to bleed completely.Compressive strength of cylinder (50x100mm) of 28 days is not smaller than 20 MPa.The rate of water/cement is not over than 0.4The content of Cl is not over 0.3kg/m3Ecflux time is from 10-15 seconds according to Marsh Cone testing. 35

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