Construction method of 14 box culvert

1、PROJECT: APPROACH ROAD OF CAN THO SIDE PACKAGE: 3CONSULTANT: JV CONSULTANT CONTRCTOR: CSCEC- 1 -CONSTRUCTION METHOD STATEMENT FOR BOX CULVERT 1.Description1.1QuantityThere are total 14 sets box culverts for drainage with two types size (Type A: 2 x 2.5 x1.5m; Type B: 2 x 2.5 x 2m) in Package3. The m

2、ore details refer to the following list:LIST OF BOX CULVERTleftcenterright1Km7+8262x2.5 x230.624.064.284.060.2drainage2Km8+8902x2.5 x238.73.33.6853.4180.55drainage3Km9+3262x2.5 x1.524.12.5022.7472.5020.252drainage4Km9+6202x2.5 x1.530.922.5142.8692.5140.264drainage5Km10+3102x2.5 x230.213.6373.93.5750

3、.825drainage6Km10+6902x2.5 x1.524.12.4192.6642.4190.169drainage7Km10+9502x2.5 x1.524.12.5392.7842.5390.289drainage8Km11+4512x2.5 x1.524.12.8433.0882.8430.593drainage9Km11+6902x2.5 x1.524.12.9553.22.9550.705drainage10Km12+1802x2.5 x232.95.1055.355.1050.7drainage11Km12+7562x2.5 x228.533.6563.93.6190.7

4、drainage12Km13+6002x2.5 x1.524.12.6242.8692.6240.374drainage13Km14+4502x2.5 x1.524.13.1993.4443.1990.949drainage14Km14+8902x2.5 x1.524.12.4252.672.4250.175drainageFinished elevation (m)Bottomelevation(m)remarkNo.StationSize (m)length(m)PROJECT: APPROACH ROAD OF CAN THO SIDE PACKAGE: 3CONSULTANT: JV

5、CONSULTANT CONTRCTOR: CSCEC- 2 -1.2Related articles Concrete:The batch plant concrete will be used for the cast-in-site culvert, and the requirement of the concrete refers to the following list:LIST OF REQUIREMENT FOR CONCRETEConcrete ClassStrengthfc (MPa)Kind of structure in useE24Box culvert, pipe

6、 culvertRetaining wall, wing wall, support of pipe, drop inlet, catch coverF20Apron, kerbG15Lean concreteRebar:NoDescriptionStrengthfy (MPa)Related specification1PLAIN ROUND BAR250(Min)ASTM A615 or equivalent2High yield deformed bar390(Min)ASTM A615 or equivalentSpecification:LIST OF RELATED SPECIFI

7、CATIONNO.RELATED SPECIFICATION1.AASHTO 98 _ LRFD BRIDGE DESIGN SPECIFICATION 2.AASHTO GUIDE SPECIFICATION FOR DESIGN AND CONSTRUCTION OF SEGMENT CONCRETE BRIDGES3VIETNAMESE HIGHWAY BRIDGE STANDARD 19792.Preparation for construction2.1 MaterialPROJECT: APPROACH ROAD OF CAN THO SIDE PACKAGE: 3CONSULTA

8、NT: JV CONSULTANT CONTRCTOR: CSCEC- 3 - Rebar: the grade, dimension should be accordance to the contract requirement, supply with certification of quality, and keep the rebar surface from rust. Cement: Use the qualified PC40 type. Course aggregate: gravel1X2cm, capacity of compress resistance500kg/c

9、m2, impurity ratio1%; Sand: course sand or river sand, impurity ration 1.3m drainage2Km8+8902x2.5 x238.70.55-0.1Max level 1.3m drainage3Km9+3262x2.5 x1.524.10.252-0.398Max level 1.3m drainage4Km9+6202x2.5 x1.530.920.264-0.386Max level 1.3m drainage5Km10+3102x2.5 x230.210.8250.175Max level 1.3m drain

10、age6Km10+6902x2.5 x1.524.10.169-0.481Max level 1.3m drainage7Km10+9502x2.5 x1.524.10.289-0.361Max level 1.3m drainage8Km11+4512x2.5 x1.524.10.593-0.057Max level 1.3m drainage9Km11+6902x2.5 x1.524.10.7050.055Max level 1.3m drainage10Km12+1802x2.5 x232.90.70.05Max level 1.3m drainage11Km12+7562x2.5 x2

11、28.530.70.05Max level 1.3m drainage12Km13+6002x2.5 x1.524.10.374-0.276Max level 1.3m drainage13Km14+4502x2.5 x1.524.10.9490.299Max level 1.3m drainage14Km14+8902x2.5 x1.524.10.175-0.475Max level 1.3m drainageBottomelevation(m)remarkNo.StationSize (m)length(m)Excavationlevel for boxculvert (m)Current

12、 waterlevel in February2009(m)According to site condition on every location, the Contractor will propose to apply two methods of excavation under water for 14 box culvert. One method is driving steel piles (L=12m) for cofferdam PROJECT: APPROACH ROAD OF CAN THO SIDE PACKAGE: 3CONSULTANT: JV CONSULTA

13、NT CONTRCTOR: CSCEC- 6 -along with the bound of excavation. Other method will use the associated operation method of collocation well and water pump to lower the water level in excavation area. The detail information will refer to follow description:cofferdamcolloctaionwell (1:1.5 or1:2 for slope)1K

14、m7+82639.6 x10.6-0.453.72Km8+89048.4 x 11.7-0.13.63Km9+32631.1 x 9.9-0.3982.74Km9+62037.9 x 9.9-0.3862.85Km10+31039.2 x 10.60.1753.86Km10+69031.1 x 9.9-0.4812.17Km10+95031.1 x 9.9-0.3612.18Km11+45131.1 x 9.9-0.0572.39Km11+69031.1 x 9.100.0552.510Km12+18041.9 x 10.60.054.711Km12+75637.9 x 11.30.053.2

15、12Km13+60031.1 x 9.9-0.2762.313Km14+45031.1 x 9.90.2992.714Km14+89031.1 x 9.9-0.4752Existinglevel (m)Excavationbottomlevel (m)No.StationApply methodExcavation sizeat bottom levelLxW (m)For box culvert 7+826: Due to the high embankment and surcharge, this box culvert will excavated more deep. And the

16、re are a lot of water will flow in to excavation pool which can be not pumped completely by water pump. Whats more, considering condition of construction and progress, the cofferdam will be carried out. The main material for cofferdam is steel sheet pile and H-beam. PROJECT: APPROACH ROAD OF CAN THO

17、 SIDE PACKAGE: 3CONSULTANT: JV CONSULTANT CONTRCTOR: CSCEC- 7 -The follow sketch shows the arrangement of cofferdam:Cofferdam for Box culvert Km 7+826PlanMain material list:No.Itemsize(m)quantity(m)used equipmentremark1Steelpile(12m/set)0.751584Vibration hammercrawler crane2H-beam0.4144Vibration ham

18、mercrawler crane3H-beam0.3105crawler cranePROJECT: APPROACH ROAD OF CAN THO SIDE PACKAGE: 3CONSULTANT: JV CONSULTANT CONTRCTOR: CSCEC- 8 -After finished the cofferdam, the big capacity water pump will pump water in the cofferdam. Then the grab will excavate soil along the bound of cofferdam to desig

19、n bottom level. For other box culvert (location refers to above list)In order to catch up our progress, the Contractor would like to propose construct 3 location box culvert at one time. So the relative equipments will be put in 3 sets. And these box culverts almost were located low embankment area.

20、 The method which the associated operation of collocation well and water pump to lower the water level in excavation area will be applied. The follow sketch will explain clear:Drainage ditchCollocation well with water pumpFoundation ditchCollocation well by reinforcement cageFit water pumpPROJECT: A

21、PPROACH ROAD OF CAN THO SIDE PACKAGE: 3CONSULTANT: JV CONSULTANT CONTRCTOR: CSCEC- 9 -Main material and equipment list:No.Itemsize(m)quantity(m)remark1reinforcement cageD=0.812Reinforcement d=25 with steelmesh,the height is 1m2Water pumprefer to watercondition12the capacity of water pump shouldbe mo

22、re the water discharge3drainage piperefer to waterpumpabout 150marrange according to site situationAnd if necessary, the drainage ditch will arrange according to actual condition on every location for drainage.The excavation grade will be 1:1.51:2 (Adjusted with the soil condition), until to the des

23、ign level. And the excavation size of bottom level refers to the above list.Rebar work: Make survey line on the completed lean concrete surface, and also make line for the rebar/ formwork arrangement, then prepare rebar work for bottom slab and side wall. Set steel pipe to support the rebar cage whe

24、n installation to prevent cage deviation. Then minimum cover to main reinforcement shall be not less than 5cm, lap spliced will be not more than one bar than bar 12m for all.Formwork: The concrete for culvert will be cast into two phases, the first phase is that cast the bottom slab concrete, and th

25、e second phase is that cast the side wall and top slab concrete, the construction joint will be set 50cm above the bottom slab. The formwork system will use wood formwork with steel pipe support; the formwork will be pre-designed, fabricated in site. The connection between the interior and exterior

26、formwork of wall will use 16 tension bar, the vertical & horizontal distance will be 60cm; Construction joint: Refer to the original design, there are two construction joints for each segment, the first joint will be set for the two segments connection location; the second joint will be set for the

27、connection between the culvert wall with the wing wall. For the first joint, the width of connection concrete will be proposed to enlarge to 25cm, 2cm cork slab will be pre-embed in the connection, sealed with waterproof strip outside. To ensure the vertical tolerance within the limited requirement,

28、 it should be prepared two separately formwork (clamp the water stop). For the second joint, remain 20 (vertical space 300mm) in the side wall of culvert, use 14 rebar to connect between the wing wall with the side wall. The connection joint detail refer to the following drawing:DETAIL CONNECTION JO

29、INT FOR CULVERT SEGMENTPROJECT: APPROACH ROAD OF CAN THO SIDE PACKAGE: 3CONSULTANT: JV CONSULTANT CONTRCTOR: CSCEC- 10 -DETAIL CONNECTION JOINT FOR BETWEEN BOX WING WALLConcrete pouring: The key point is the second phase for concrete casting, and the important point for the concrete casting is side

30、wall construction. The height of side wall will be 2.0m (1.5m, 3.8m and 4.0m); casting with conduit pipe, remove the pipe per 1.5m. Keep the rebar out in the area of conduit pipe to easily casting. Complete rebar installation when the side wall concrete is totally casting. Cast side wall concrete 50

31、cm per layer. The concrete should be pumped into the formwork equality, the specify worker will be equipped with each poker vibrator and located in specify area. Conform to the working sequence: side wall to middle wall, then other side wall, for each layer and turn. While complete the side wall con

32、crete, begin the top slab concrete.Concrete curing: After the last treatment to surface of the top slab, cover the surface with sacks, keep moisture for 7 days.The non-bearing formwork will be dismantled after 1 days, the bearing formwork will be dismantled after 3 days.4.Quality assurance4.1RebarPR

33、OJECT: APPROACH ROAD OF CAN THO SIDE PACKAGE: 3CONSULTANT: JV CONSULTANT CONTRCTOR: CSCEC- 11 -The rebar type, quality, weld rod, weld flux, will be accordance with the contract requirement,The rebar lap length, quantity, space, anchor distance will be checked and accordance the requirement as descr

34、ibed before. The quantity of loose binding for rebar will be kept within 10% of all.The rebar splice and lap length will be accordance with the requirement, and checked strictly. 4.2FormworkThe formwork support should have enough bearing capacity and stability. The supports have enough support area.

35、The gap between the formworks will be controlled within 1.5mm.The interface between the formwork and the concrete should be cleaned and pre-treated with insulate agent to prevent sticking. The total area of insulate agent will not more than 1,000 cm2.4.3ConcreteThe cement, water, aggregate, adhesive

36、 agent will be accordance to the material requirement and approved by the Engineer.The mix design, material measurement, mixture method, curing and construction joint should be pre-taught to the specify staff, and operate followed the standard procedure.The sample cube will be tested as the AASHTO 98 requirement; the test result sh