Construction Method Statement of
Water Supply, Drainage and Firefighting Engineering
in Dry Port
The water supply engineering of this project contains 1946m installation of PE?DN50~DN300?water supply pipeline and 12 valve pits. The water drainage engineering is constituted by 2256m installation of HDPE ?DN50~DN300?plastic pipeline, 50 cast-in-site reinforced concrete square manholes, 8 brick round manholes, 84 gutter with single grating, and the installation of oil wastewater treatment plant. The firefighting engineering mainly contains 10 outdoor below-ground and above-ground hydrants and 9 outdoor reinforced concrete below-ground hydrant pits.
? Construction Staff, Machinery and Equipments, and Schedule
2.1 List for Construction Staff
Table 1: Construction Staff
No. Type of Job Post Quantity 1 Project Manager 1 2 Deputy Project Manager 1 3 Project Deputy Chief Engineer 1 4 Engineer 2 5 Technician 1 6 QA/QC Engineer 1 Management 7 HSE Engineer 1 8 Test Engineer 1 9 Machine Engineer 1 10 Business Engineer 1 11 Survey Engineer 1 12 Material Engineer 1 13 Machine Driver 8 14 Machine Repairman 2
Operation 15 Foreman 2 16 Technical Worker 30 17 Local Worker 30 2.2 List for Construction Machinery and Equipments
Table 2: Construction Machinery and Equipments No. Name Model Unit Quantity 1 Crane 40T/55T 1 2 Excavator PC200 1 3 Concrete mixing plant 120m3/h Set 1 4 Concrete delivery truck HDJ5241JBFU 2 5 Generator 4BTA3.9-G2 50KW 1 6 Water truck SLA5200GPSE 1 7 Oil truck SLA5152GJYE 1 8 Total station instrument TC802 1 9 Gradienter NA2 1 10 Electric melt machine 2
Electromotion booster 11 1 pump
2.3 Construction Schedule
thThe construction shall be started on July 15 2009, and completed on
thDecember 27 2009.
? Construction Method
3.1 Construction Technology Process
The construction technology process of water supply and firefighting
foundation trench engineering shall be as follows: setting-out survey?
excavation? foundation tamping? pipelines installation? pipeline joints
treatment? well chamber construction? pipeline pressure test? firefighting
equipments installation? foundation trench backfilling and tamping.
The construction technology process of water drainage engineering shall contain: setting-out survey? foundation trench excavation? foundation
tamping? pipelines installation? pipeline joints treatment? well chamber
construction? sealing test? foundation trench backfilling and tamping
3.2 Construction Method
3.2.1 Setting-out Survey
According to design drawings, pipelines shall be set-out and surveyed, mainly for marking the positions and elevations of the trenches in site. 3.2.2 Foundation Trench Excavation
The foundation trench shall be excavated mainly by excavator, finished manually. The excavation by machine shall be till 0.1m above the bottom of foundation trench according to pipe diameter and design requirements, continued to be cleared manually to designed elevation, with no disturbance to parent soil.
For water drainage engineering, if the excavation depth is beyond 2m, channel beams shall be used for temporarily vertical supports on both sides, which shall also be supported by profiled steels at certain intervals to keep the
stability of both slopes. The temporary supports need to be approved by Employer’s Representative before use.
3.2.3 Foundation Tamping
With the completion of foundation excavation, the surface of foundation bottom shall be tamped by tamping machine before paving medium-coarse sand foundation of 10cm thickness, also tamped by tamping machine and watered.
Table 3: Test of Foundation
Test No. Test item Test standard Test frequency method
Compaction Sand Comply with One point for every 50m 1 degree replacement design requirement of foundation trench
3.2.4 Pipeline Installation
The center line shall be set out before installing pipelines manually assisted by truck crane. The pipes shall be colligated by soft ropes and put in the trench slowly with supports and sprags fixing temporarily. Each pipeline shall be installed on the paved sand bedding course tightly and combined well for uniform bearing.
Table 4: Allowable Deviation of Pipeline Installation
Water drainage pipe Water supply pipe
Position of axes 15 30
Elevation of pipe inner bottom ?15 ?30
3.2.5 Pipeline Joints Treatment
The pipeline shall be jointed by electric melt sleeve in accordance with design requirements. The voltage and heating of electric melt shall comply with the provisions of electric melt joint machine and welding technics parameters. They will be recorded. While welding, the current status shall be watched. During cooling time, the connection fittings can’t be removed or forced The
cooling method shall adopt natural cooling, not appropriate to be forced cooling,
3.2.6 Pipeline Wash and Disinfection
With the completion of water supply pipeline installation, the inner part of pipeline shall be cleaned before hydraulic test. For the portable water pipes, they shall be disinfected by dissociating chlorine before use according to design requirements.
After pressure test, the pipe shall be disinfected by keep full water with dissociating chlorine of 20?30mg/l for over 24 hours.
3.2.7 Well Chamber Construction
The well chamber construction shall be carried out subsequently after pipeline installation, including round valve pit φ1200mm, outdoor reinforced
concrete below-ground hydrant pit Φ1200mm, and square manhole 1100×
1100mm, strictly following design requirements and related standards.
For installing the well ring, the center line shall be set out by surveyors first, and the top elevation must be controlled by level instrument, The cast iron well bottom between well ring and well chamber shall be filled with M10 cement mortar of 10mm.
a. Concrete Bedding Course Casting?C10?
With check out of foundation tamping, the position and elevation of concrete bedding course sidelines shall be set out before concrete casting. The C10 concrete shall be delivered to foundation bottom by crane raising cage, spread manually, vibrated and compacted by flat slab.
b. Reinforced Bar Colligation and Installation of Embedded Units and Formworks
The reinforced bar colligation shall be carried out after lean concrete bedding course construction. According to design drawings, the framework of reinforced bars shall be checked and accepted entirely.
Both inner and outer side formworks shall adopt light-duty steel structure, installed and removed by crane with manual assistance.
c. Concrete Casting and Curing
The concrete shall be transported to site by concrete trucks, casted
assisted by raising cage of crane, spread in formwork manually with a height of free fall less than 3.0m, vibrated and compacted with individual thickness of 30?50cm,
The formwork can only be removed after the concrete reaches certain strength, immediately curing by fresh water.
Table 5: Allowable Deviation of Well Chamber
Item Allowable deviation?mm?
Length, width ?20
Dimension of w