Methodology for RE Panels And Reinforcment Detais in PDF | Methodology for Crafting Precast RCC Facia Panels
Objective:
The objective of this method statement is to describe in detail all the operation connected with the casting of precast panels/Blocks for Reinforced Earth structure
Scope of Work:
The work covers pre-casting of RCC fascia panels/Blocks with M35 grade of concrete for the construction of Reinforced earth structures.
References:
MORT&H Specifications Section-3100 and Contract Document.
Resources:
1. Materials:
The following materials are required for the casting of precast panels/Blocks and their specifications in brief are as follows:
Facia Units: The facia units, which help maintain a vertical face of the reinforced soil/ earth structure, will be of the pre-cast reinforced concrete panels. The grade of concrete will be M35 conforming the section 1700 of MORTH Specification. The shape of panels is cruciform of size 1.5m x 1.6m with thickness as shown in the drawings. Reinforcement shall be placed as shown on the plan and shall conforming to the section 1600 of MORT&H.
2. Plant and Equipment
- Batching Plant (60/30Cum / Hr) :1 No
- Hydra Crane : 1 No
- Vibrators with Needles : 2 Nos
- Transit Mixers : As Required.
- Gas cutting torch and accessories : 2 Nos.
- Welding machine : 2 Nos.
- Cube moulds : 1 No.
- Slump Testing Apparatus : As Required
Procedure
Casting: The elements shall be cast in a pre mould form placed on a specially erected stand on a flat area in Camp 1A & Camp 1B. Lug connectors and lifting devices shall be cast in place to the dimensions and tolerances shown on drawing (Annexure“-1) and lug connectors shall be set on the rear face, prior to casting: The concrete in each unit shall be placed without interruption and shall be compacted by the use of a vibrator supplemented by such hand tamping as may be necessary to ensure that the concrete reaches into the corners of the forms and prevent formation of loose pockets or cleavage planes. Clear form oil of the approved quality shall be used
Curing: The precast elements shall be cured for a sufficient length of time as approved by Engineer so that the concrete develops the required compressive strength. Only fresh potable water shall be used for curing.
Removal of forms: The precast panel shall remain on the base form work until the concrete attains 15mpa compressive strength.
Scribing: The date of manufacture and nomenclature shall be clearly scribed on the rear face of each unit.
Concrete Finish: The front (exposed) face of the elements shall have the uniform texture. The rear face shall have the finish of unformed surface and shall be roughly screened to eliminate open pockets of aggregates.
Tolerances:
All dimensions within 5 mm
Evenness of the front face1500mm :±5mm over
Difference between lengths of two diagonals :10mm max.
Thickness : ± 15 mm
Handling, Storage and Transporting:
All elements shall be handled, stored and transported in such manner as to eliminate the danger of chipping, cracks, fracture and excessive bending stresses. Elements in storage shall be supported on firm blocking located adjacent to the tie-strips to avoid bending.
Acceptability:
Acceptability of the precast elements shall be determined on the basis of compression tests, as per MORT&H. specifications and visual inspection. A minimum of one sample of 6 cubes shall be taken for each lot of 5 cum or 12 cubes above 5 cum per day. Elements shall be acceptable for placement in the structure if the strength at 10 days, or before, exceeds 75% of the 28 days requirements.
Safety : The following measures will be taken observed in addition to safety precautions taken at construction sites, while carrying out post tensioning operations.
Inspection, Testing and Control:
Inspection of precast panels shall be done through regular RFI.