Method statement in english.docx

1、Method statement in englishMethod Statement for Construction of EPC Project United Arab Emirates1、 General The Renovation & Expansion of EPC Harbour United Arab Emirates includes civil building & marine works and its ancillaries. The main works are: removal of existing buildings & re-construction; e

2、xpansion of the existing quay wall, such as cast-driven in situ quay wall piles, bored anchor wall piles, anchorage system installation, paving, basin dredging, dismantantling & re-installation of marine furniture etc. 2、 Construction arrangement for working procedures Regarding general construction

3、 arrangement, totally three working facets i.e. civil building, marine works & installation of plant & equipment shall be developed alternatively & logically, of which, the quay wall construction is the key line for the whole works. The site office would be made of caravans, which are mobile from ti

4、me to time in accordance with the site progress without causing any affect to site work. The quay wall will be constructed in sections. Only when the 200m-long northern quay wall is built & put into use so as to guarantee the normal running of harbour operation can we start the remaining quay wall w

5、ork. The cast-driven in situ quay wall piles are proposed to start from the northern bank of the existing quay wall & proceed to the direction of the western bank. After installation of the tubular piles to the designed level, a construction platform supported by the land-based tubular piles & exist

6、ing quay wall could be built. The drilling plant could be positioned on the platform & be used to do the pile foundation work. The bored anchor wall piles would be constructed at the same time. The dismantling of the existing quay wall pavement, piles & capping beams etc & installation of the anchor

7、age system should also be carried out closely along with the pile foundation work without causing effect on the tie rod works. The dredging of the basin could be divided into two steps: i.e the first step is to dredge the area 50m outside from the cope line, the remained area in front of the cope li

8、ne would be excavated with the main quay wall body is complete. Power supply: two sets of generators would be provided for power supply.Main flowchart of works ：Construction Preparation Land based pile positioning Anchor beam The boring forming & concreting Dismantling of part of quay wallBackfillin

9、g before Anchor beam Work behind quay wallWork completion Revetment worksBored pile concrete Superstructure of quay wallTie rod adjustmentBackfilling behind the pileDriving of pilesPlatform construction Underwater checking & removal of obstruction Dredging of basinTie rod works 3、Main Working Proced

10、ures3.1 Cast-driven in situ Quay Wall PilesDriving of tubular piles Prior to pile driving, the divers shall be employed to check the sea bed, all the obstructions if any should be removed. The existing quay wall should be strengthened if deemed necessary so as to guarantee the safe & smooth driving

11、of piles. The tubular piles should be accurately pitched by means of a guide frame. The guide frame will be supported by two tubular piles & connected with the capping beam horizontally so as to easily adjust the positioning. The length of the guide frame should be 10m and totally 8 Nos of piles cou

12、ld be driving during each panel placement. When the first panel is complete, the guide frame would be moved forward for the pile driving of next panel. The tubular piles will be driven by means of a 40t crawler crane equipped with hydraulic vibrating hammer until the designed bottom level is obtaine

13、d. The head level of the top of the piles to be slightly higher than the exiting quay wall surface. During pile driving, attention shall be given to maintain a truly vertical alignment so as to avoid any problems due to pile out of verticality & causing unnecessary damage to the pile ears. Boring dr

14、illing & casting of reinforced concreteAfter the tubular piles are driven, a platform will be built with the support of the tubular piles & the existing quay wall. The platform will be covered with steel plate upon which the GPS-15 drilling machine will be supported. The boring & concreting casting

15、will be carried out in an intermittent manner, i.e. as a pile is concreted, the next two adjacent piles will be left for a while and the fourth along will be concreted so as to keep an interval of two(2) piles space to guarantee the work quality. ( please see the following illustration)A） the sketch

16、 for forming the boring is as follows：B Working flowchartC/ Construction hold points a) Survey & setting outThe central points of each pile could be set out by means of Total Station & the survey record should be submitted for the double-checking & final approval of the Consultant. Each pile would b

17、e pitched securely by means of guide frame.b) Positioning of drill Before assembly of the drill, all the preparatory work shall be well done. The movable rails & wooden sleepers shall be installed in such a manner that the stability of the drill is always maintained. The slurry pump should be as clo

18、se to the pile position as possible. In the meantime, the slurry recycling system should be well prepared to assure that the slurry can be cleaned and be recycled back to the boring. c) Boring drill i) The drill shall be properly positioned to assure that no displacement & tilting movements can occu

19、r. The survey control lines shall be marked on the frame so that during construction, the survey work could be easily observed & recorded. ii) The choice of drilling auger should be made depending upon the soil to be excavated. Normally a shell auger will be used, while in the event of harder materi

20、al, the spiral auger should be used.iii) Initial drilling: start the slurry pump & turn plate to let the machine revolve idling for sometime. When the slurry is sufficiently filled into the boring, the drilling can start. The silt & clay stratum can be drilled fast, the sand stratum will be drilled

21、at a lower speed. The slurry density could be 1.05-1.10g/cm3，the viscosity should be 18-20s. No interruption during drilling is allowed. If there is any stoppage of drilling, the time & reason should be recorded & the slurry shall be maintained so as to hold up the sides of the boring.d) Rock type c

22、hecking & the boring cleaning & acceptanceWhen the pile excavation has been drilled to its designed bearing stratum, the Consultant would be invited to check & confirm whether the depth of the boring and the depth of the rock foundation are satisfactory as per the design requirement. When approval i

23、s given, the boring will be cleaned. During the boring, the drilling debris will be cleared out by the flushing action of the slurry that is pumped to the base of the pile and then is filtered in the recovery plant during the drilling process. In order that the bottom of the boring is maintained as

24、cleaned, prior to lengthening the drilling pole, the drill would be kept idling work for 2-3minutes until all the debris inside the drilling poles are cleaned out along with the washing liquid.When the final depth is achieved, the boring shall be washed until the input & the output slurry are at the

25、 same density. Before placing of tremie concrete, the bottom debris should be checked & a 2nd cleaning of the boring may be performed if necessary. e) Treatment of slurry The slurry pumped out shall be pumped into a large precipitation basin made of blocks. The silted sand will be cleared out by mea

26、ns of sand removing machine until the sediment contents & the slurry density is in compliance with requirements. The approved slurry after checking by slurry viscometer can be re-used for construction.The surplus sediment will be temporarily stored in the basin until it is full, then the whole sedim

27、ent could be cleared out & be disposed of in the designated pits.f) Fabrication of the steel reinforcement cageThe steel reinforcement cage should be fabricated in the workshop as per the designed drawings. For each cross section, the overlap area of the main bars shall not be more than 50% of the s

28、ection area. The overlap or joint area should be made in a stagger manner.Spacer will be fixed at 2.5m intervals along the main bars so as to assure the correct thickness of concrete cover. During storage, handling & delivery of the reinforcement cages, proper measures shall be taken to avoid any de

29、formation & rusting of the reinforcement cages. g) Installation of the tie rodIn order to avoid any effects to the concrete inside the piles, the tie rod ends shall be placed close to the internal side of the concrete cage. When the concrete is poured & before the concrete has set, the tie rod will

30、be inserted into its designed central position of the piles. The tie rods shall be placed horizontally without displacements so as to introduce other stresses. During backfilling, attention shall be given so as to avoid any damage to the tie rods. After backfilling, all the tie rods shall be adjuste

31、d to create a uniform stress to the whole tie rod system.h) ConcretingThe concreting will be done by means of 250mm tremie pipes with each 1.5-4.0m long & connected with flanges. The pipe joints should be fitted with =5mm rubber ring to keep them watertight. Each pipe joint end shall be maintained v

32、ertically & be placed down the pile shaft slowly to avoid any twisting. The upper part will be fitted with funnel of about 2m3, when the first funnel of concrete is poured, the tremie pipe should be buried into the concrete around 0.8m deep.According to the site conditions, the ready-mixed concrete would be pumped into the tremie pipe funnel. Before placing of the first funnel of the concrete, a concrete cork of 220mm dia, 270mm