The Scope of the Quality Plan covers the following activity:
Site Clearance including removal of trees, Bushes, stumps etc. Excavation necessary for the construction of Slab culvert as per technical specification and most specification. Construction of Slab culvert as per technical specification and MORT&H Specification.
The following abbreviations shall have the meaning as set forth below
MORT &H: Ministry of surface Road Transport & Highways
IRC : Indian Road Congress
IS : Indian Standards
MORT&H specification for road and bridge works (5th Revision) Tender Technical Specification
CONSTRUCTION METHODOLOGY OF SLAB CULVERT
1. Personal to be deployed:
Section In charge will be responsible for the execution as well as quality control of the section for construction of Slab Culvert.
2. Equipments to be deployed:
Mobilization of Plant / Equipment / Machinery shall be as per requirement of finalized and approved construction schedule/programmed.
1.Batch Plant (RMC) -60
2.Transit Mixer cum/hr -6 Cum
3.Vibrators -As per requirement
3. Site Clearance Works:
Site clearance, grubbing, dismantling of existing structure and disposal of unserviceable material at designated area and stacking of serviceable material shall be carried out as per MORT&H specification, section – 200 and as per modifications to MORT&H clause, 201.1, 201.4, 201.5, 202.4 and 202.5 furnished in additional technical specification of the project.
4. Survey and Setting out works:
After the site has been cleared, the limits of excavations shall be set out after center line marking true to lines, curves, slopes, grades and sections as per shown on the drawings as directed by the engineer and as per established bench marks / co-ordinates.
All the survey instruments used shall be calibrated periodically as per calibration plan. Survey check reports / other relevant data shall be maintained in relevant inspection formats.
5. Construction operations
A) Excavation: – After the site has been cleaned according to clause 201. The
limits of excavation shall be setout true to lines, curves and slopes. The excavation shall be carried out as per MORT&H clauses 304.3.2 & 2903. The depth to which excavation shall be as shown on the drawings, where water is met with in excavation due to stream flow, seepage, springs etc; adequate measure shall be taken to pump out water to keep foundation trenches dry.
B) The bottom of foundation shall be leveled both longitudinally and transversely and compacted by suitable compactor to achieve the required compaction.
C) Over compacted earth a leveling course of concrete of required thickness and grade as specified in drawing shall be laid.
D) Reinforcement shall be corrosion resistant reinforcing bars HYSD/TMT type or equivalent confirming to IS specification 1786. The reinforcement steel will be procured from approved source. Different dia of reinforcement steel shall be stocked separately above ground level / floor level to avoid contact with water. Bar bending schedule shall be prepared and got approved from engineer. Bars shall be cut and bent cold to the specified shape and dimension. Reinforcement bars shall be placed accurately in position as shown on drawings. The bars crossing one another shall be tied together at every intersection with binding wire, that should be annealed 18-20 gauges mild steel. Necessary stays, a concrete blocks, chair spacer shall be provided to fix the reinforcement in its correct position. Placing and fixing of reinforcement shall be inspected and approved by engineer before placing of concrete.
E) Shuttering vertical props and cross bracings of sufficient strength shall be used to protect any bulge / deformation of concrete. All the joints shall be properly sealed. PVC joint, sealing tapes, foam will be used in order to prevent leakage of slurry.
F) Weep holes shall be provided as per drawing and specification.
G) Concrete of required grade and specification and as per approved mix design shall be mixed at batching plant and transported to site by using Transit Mixers. Concrete of grade as specified in drawings will be laid in the bottom raft portion including haunch portion. Then sidewall will be constructed in one lift depending on the height mentioned in drawing. Concrete will be poured in the erected formwork by using Chutes or manually and compacted by using needle vibrators. Second phase of shuttering and formwork shall be erected for the top slab and remaining portion of wall. Tying of slab reinforcement shall be done as per drawing. Then concrete shall be poured and compacted. Concrete shall not be freely dropped in to place from a height exceeding 1.5m. Curing shall be done for 14 days by keeping surface moist. Cubes shall be taken and tested for compressive strength. Slump shall be taken at delivery point to maintain the workability of the concrete.
H) In case of widening, for joining with existing slab culvert 600 mm slab of existing structure slab to be dismantled and over lapped with the new slab reinforcement. If joining with existing Arch culvert, 300 mm Arch of culvert will be dismantled and reinforcement of new culvert will be embedded in that.
TESTING AND ACCEPTANCE PROCEDURES:
The materials used in construction are tested as per relevant IS code and specifications to verify its suitability.
- Cement (As per IS 4031)
- Coarse aggregate (As per IS 383 and IS 2386)
- Fine aggregate (As per IS 383 and IS 2386)
- Reinforcement (IS 1786 and IS 432)
Water – water used for mixing and curing shall be clean and free from injurious amounts of oils, acids, salts, sugar etc.
Cube strength – 150mm cube shall be made cured and tested at the age of 28 days for compressive strength in accordance with IS 516.
All the Inspection and Test requirements shall be followed as per Technical Specifications and other Codes/Standards.
Any Non-Conformity observed during Field Inspection and also during Testing of Materials the same Non-Conformity shall be recorded in the specified Format and necessary Corrective/Preventive actions shall be initiated to prevent such things in future.
AVAILABILITY OF MATERIALS:
Sufficient quantity of well graded and good quality materials will available at site during construction works.
1.All the personnel in the operation shall be wearing the personal safety gear like safety helmets, belts and shoes during the operations.
2.The work site would be cleaned of rubbish, loose materials, cut rebars from the site at regular intervals and good housekeeping would be maintained at site.
3.During welding or gas cutting, the operators shall be wearing safety goggles or safety shield.
Safe access will be made for each lift for carrying out work and inspection.
frequently asked questions (FAQs) related to slab culverts:
What is a slab culvert?
A slab culvert is a type of culvert structure that consists of a solid, flat, and typically reinforced concrete slab supported by abutments or walls on both sides. It is used to allow water to flow beneath roads, railways, or other obstacles.
What are the advantages of using slab culverts?
Slab culverts are cost-effective for small to medium-sized water crossings, relatively easy to construct, and provide a flat surface for vehicular traffic. They are suitable for areas with moderate flow conditions.
When are slab culverts commonly used?
Slab culverts are commonly used in areas with low to moderate water flow, such as in rural or suburban settings. They are suitable for small streams, drainage channels, or other watercourses.
How is the slab in a culvert reinforced?
The concrete slab in a culvert is often reinforced with steel bars or mesh to enhance its structural strength. This reinforcement helps the slab withstand the loads imposed by flowing water and other environmental factors.
What considerations are important in designing a slab culvert?
Design considerations include factors such as the size and shape of the watercourse, anticipated water flow, soil conditions, and the type of traffic using the road. Proper hydraulic calculations and structural analysis are essential in the design process.
Are there variations in slab culvert design?
Yes, variations in design may include different shapes and sizes of culverts based on specific project requirements. Additionally, features like end walls, headwalls, and specific inlet and outlet configurations may vary.
How is the water flow managed in a slab culvert?
Inlets and outlets in a slab culvert are designed to guide and manage the flow of water. Proper sizing and placement of these openings ensure efficient water passage through the culvert while preventing issues such as erosion.
What maintenance is required for slab culverts?
Regular inspection for signs of wear, damage, or blockages is essential. Maintenance may involve clearing debris, ensuring proper water flow, and addressing any issues with the culvert structure.
Can slab culverts accommodate pedestrian and bicycle traffic?
Yes, slab culverts can be designed to accommodate pedestrian and bicycle traffic. Proper consideration of the width and safety features is essential when designing culverts for mixed-use, including non-motorized traffic.
Are there environmental considerations for slab culverts?
Yes, environmental impact assessments may be required during the planning phase to ensure that the construction and presence of the culvert do not negatively affect the surrounding ecosystem, water quality, or wildlife.