Reinforcing and Form-work in EHV Cable Installation Project

Fig-Barbade Wire Tie

Form-work and Reinforcing in Underground Cable Installation Civil Work

The steel reinforcing bars shall be in the form of round or deformed bars and shall be made by approved manufacturers in accordance with the requirements of B.S. 4449, B.S 4461 and B.S. 4483 as applicable and bent to comply with B.S. 4466. The minimum bar size to be used shall be 8 mm diameter. Welding of bars for extensions shall not be permitted. Bend tests shall be carried out on site to cheek the quantity of rebar.

 How Binding Wire?

Metal reinforcement is to be secured against displacement by using N. 16 SWG annealed iron wire ties or suitable clips at inter-sections. Tails of all wire ties shall be bent away from adjacent concrete surfaces. All rebar shall be held rigidly in place so that it cannot move during concreting.

 Storing Procedure

All reinforcing bars shall be stored on the site on timber supports at least 200 mm clear of the ground.

Fixing Technique

The number size form and position of all the reinforcement shall unless otherwise directed or authorized by the Engineer be strictly in accordance with the Contractor’s approved drawings. Nothing is to be allowed to interfere with the disposition of the reinforcing bars and the Contractor is to make a particular point of seeing that they are placed correctly in every respect. The minimum cover to any reinforced bar shall be at least 75 mm when below ground.

Sponsored:

Cleaning System

All reinforcing steel shall be free from heavy rust loose scale oil and grease or other deleterious material immediately before the concrete is placed in forms.

 How Take Approval?

The Contractor must obtain the written approval of the Engineer to the reinforcement when placed before any concrete is placed.

CIVIL WORK & FORMWORK

Formwork shall include all temporary moulds for forming the concrete to the required shape.

Construction Works

Timber forms shall be constructed of sound well seasoned timber or prefabricated steel forms may be used.

The formwork shall be fixed in perfect alignment sufficiently rigid and strong and securely braced so as to be able to withstand without appreciable displacement deflection or movement of any kind the weight of the construction and the movement of persons, materials and plant. All joints are to be grout tight to prevent leakage of liquid from the concrete, wedges and clamps are to be used wherever practicable.

All forms shall be aligned to a tolerance of ± 3mm.

How take Preparation?

Before any concreting is commenced forms and centering shall be carefully examined and the space to be occupied by the pour thoroughly cleansed out. The inside of forms shall be treated with a coating of an approved substance to prevent adhesion and the forms shall be thoroughly wetted shortly before concreting is commenced.

No concreting shall be commenced in any portion of the Works until the preparations have been approved by the Engineer.

Striking

Forms shall be removed in such a manner as will not injure the concrete and no formwork until the concrete has sufficiently set and hardened.

Damage Concrete

The Contractor shall make good at his own expense any injury to the concrete work and any damage caused by or arising from the removal and striking of forms and supports. The attention of the Engineer must be drawn to any damage so caused and no repair work carried out without the prior approval of the Engineer.