NPQSC3-20 Reinforcement

Version 1.0

National Productivity and Quality Specifications (NPQS)

C3-20 Reinforcement

NPQSC3-20 Reinforcement

CONTENTS

Page

1. GENERAL 11.1 Scope 11.2 Related Sections 11.3 Standards 11.4 Trade Preambles 2

2. PERFORMANCE REQUIREMENTS 32.1 Detail Reinforcement Drawings and Workshop Drawings 32.2 Bar schedule 3

3.0 MATERIALS 43.1 Reinforcement 43.2 Welded Fabric Reinforcement 43.3 Couplers 43.4 Spacers 4

4.0 WORKMANSHIP 54.1 Storage 54.2 Cutting, Bending and Fixing 54.3 Tying and Welding of Reinforcement 54.4 Surface Condition 54.5 Cages for Precast Units 54.6 Cover 64.7 Ground Bearing Slabs 64.8 Laps 64.9 Anchorages 64.10 Exposed Reinforcement 64.11 Accuracy 6

5.0 VERIFICATION AND SUBMISSIONS 75.1 Submissions 75.2 Sample Tests 7

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1. GENERAL

Read with the General Requirements section, and all other contract documents.

1.1 Scope

This section covers general requirements for bars and welded fabric reinforcements used inreinforced concrete elements.

This document specifies project specific data to be read in conjunction with section C3-20 ofNPQS. All modification and additions noted in this document take precedence overclauses noted in NPQS. Clause references in this document tie with those in C3-20with the same clause title.

1.2 Related Sections

No item.

1.3 Standards

1.3.1 Standards

Unless otherwise agreed by the SO, ensure all of the Works comply with the relevantrequirements of the Standards and Codes listed below or referenced in the body ofthe Specification. Alternative Standards and Codes may be proposed for approval bythe SO, provided it can be demonstrated that the alternative Standards and Codescomply with the requirements of the standards specified. All Standards and Codesquoted are the current version, unless specific year references are noted.

Singapore Standards

SS 2 Steel for the reinforcement of concrete

Part 1 Plain bars (steel grade 300)

Part 2 Ribbed bars (steel grade 500)

Part 3 Plain and ribbed bars (steel grades 250 and 460)

SS 18 Cold-reduced steel wire for the reinforcement of concrete andthe manufacture of welded fabric

SS 32 Welded steel fabric for the reinforcement of concrete

Part 1 Steel grades 300 and 500

Part 2 Steel grade 485

SS CP 65 Structural use of concrete

Part 1 Design and construction

Part 2 Special circumstances

SS CP 83 Construction computer-aided design (CAD)

SS 117 Hot dip galvanized coatings on iron and steel articles

Other Standards

BS 6744 Stainless steel bars for the reinforcement of and use in concrete– requirements and test methods

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BS 7123 Metal arc welding of steel for concrete reinforcement

BS 8666 Specification for scheduling, dimensioning, bending and cuttingof steel reinforcement for concrete

BS ISO 4654 Epoxy-coated steel for the reinforcement of concrete

In the event that the standards or codes are revised or superseded, refer to the latest editionor the appropriate substitution for the relevant subjects.

1.3.2 Technical Reference

Refer to the following technical reference for guidance in carrying out the works.

a. CIRIA Report 92 (1981) Reinforcement connector and anchorage methods

b. Concrete Society Technical Report No. 51 Guidance on the use of stainless steelreinforcement

c. Spacers for reinforcement concrete by Concrete Society Report CS 101 (1989)

1.4 Trade Preambles

1.4.1 Detail Reinforcement Drawings

Refer to the PSD for requirement of producing detail reinforcement drawings based onreinforcement schedules shown in the structural drawings.

Do / Do not produce detail reinforcement drawings based on reinforcement schedules shownin the structural drawings. Produce the drawings for the following locations:

Location Structural Elements Reference Drawing No.

Submit ____ sets of detail reinforcement drawings to the SO for acceptance prior toconstruction. Allow at least ____ days for review.

Engage qualified and experienced personnel to prepare the detail reinforcement drawings forsubmission to the SO for acceptance prior to construction.

1.4.2 Workshop Drawings and Bar Schedules

Engage qualified and experienced personnel to prepare workshop drawings and barschedules prior to construction.

1.4.3 Quality Control Plan

No items.

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2. PERFORMANCE REQUIREMENTS

2.1 Detail Reinforcement Drawings and Workshop Drawings

To comply with SS CP 83.

2.2 Bar schedule

To comply with BS 8666.

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3.0 MATERIALS

3.1 Reinforcement

3.1.1 Reinforcing bars

Use the following types, to SS2.

a. Plain bar reinforcement: Grade 250 or 300 as specified in the drawings.

b. Deformed bar reinforcement: Grade 460 or 500 as specified in the drawings.

3.1.2 Galvanized Reinforcement

Comply with SS 117 after cutting and bending. Thickness of galvanised coating to be inaccordance with clause 6.2 of SS 117.

3.1.3 Stainless Steel Bar Reinforcement

To BS 6744, type 304 S31 and 316 S33, strength grade 250 for plain round bars and grade460 for deformed high yield steel bars.

3.1.4 Epoxy Coated Bar Reinforcement

To BS ISO 14654, bond classification type 1 or 2 as indicated in the drawings. Handle and fixso as to avoid damage to the coating, and avoid exposing the underlying steel.

3.2 Welded Fabric Reinforcement

To SS 32.

3.3 Couplers

Performance requirements of couplers shall be in compliance with CIRIA Report 92. Carryout installation in strict accordance with the manufacturer’s recommendation, subjectto acceptance by the SO.

3.4 Spacers

Detail, supply and fix all spacers, in accordance with SS CP 65:Part 1, Clause 7.3. Seek SO’sacceptance for spacers where the concrete will be exposed subsequently.

Mortar spacers to have durability and strength characteristics not less than the surroundingconcrete.

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4.0 WORKMANSHIP

4.1 Storage

Store reinforcement clear of the ground, and protect from mud, oil and other substances thatmay adversely affect its use in the works.

Deliver and store steel fabric in flat.

4.2 Cutting, Bending and Fixing

In accordance with SS CP 65: Part 1, Clauses 7.2 and 7.3.

4.3 Tying and Welding of Reinforcement

4.3.1 Tying Reinforcement

Tie reinforcement with black annealed mild-steel 16-gauge tying wire.

Tie stainless steel reinforcement using 16 swg annealed stainless steel wire.

4.3.2 Tying Wire

Bend all ends away from the concrete face and remove all loose ends before placingconcrete.

4.3.3 Welding of Reinforcement

Permitted only with the prior written approval of the SO. Where permitted, carry out inaccordance with BS SS CP 65: Part 1, Clause 7.6 and BS 7123.

4.3.4 Welding Procedures

All work is to be carried out by properly qualified welders using approved procedures.

4.3.5 Welding of Galvanised Reinforcement

Not permitted.

4.4 Surface Condition

At the time of placing concrete, ensure the reinforcement are clean, free of corrosive pitting,loose rust and mill scale and other substances that may adversely affect the bondwith concrete. Light surface rust is acceptable.

4.5 Cages for Precast Units

Make up cages and fix securely in accordance with the reinforcement drawings to provideadequate rigidity and to ensure that the specified cover and fit within the moulds areachieved.

Reinforcement not exceeding 12mm in diameter which projects from the face of the units maybe bent to facilitate the casting or demoulding of the unit subject to approval for eachcase.

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4.6 Cover

Maintain concrete cover to reinforcement as shown on reinforcement drawings. Ensure thatthe actual cover to all reinforcement is not less than the nominal cover minus 5 mm.

Before concreting, check thoroughly that the specified cover dimensions have been obtained.

4.7 Ground Bearing Slabs

Where these are reinforced with a single layer of fabric in the upper part of the slab, the fabricmay be placed in position on top of the first compacted layer of concrete, followed bythe top layer of concrete, placed within 30 minutes of the first layer.

4.8 Laps

Lap reinforcement as shown on the drawings unless otherwise agreed with the SO.

Where laps required are not shown in the drawings, propose suitable location for SO’sacceptance. Comply with the requirements of SS CP 65: Part 1, Clause 3.12.8.

4.9 Anchorages

Protect all steel parts from corrosion and keep all threaded parts protected until used. Keepall devices free from any coating or contamination.

Anchorages, including buried dead anchorages, shall be fixed with due regard to coverrequirements for corrosion resistance and fire protection.

4.10 Exposed Reinforcement

In the event that reinforcement are expected to be exposed for a prolonged period over threemonths or such that loose rust and scale may form, apply a corrosion protectioncoating to SO’s acceptance. Ensure the coating is compatible with the concrete andwill not reduce the bond of the reinforcement.

4.11 Accuracy

4.11.1 Cover to Reinforcement

Unless otherwise specified, ensure tolerances to be in accordance with SS CP 65:Part 1,Clause 7.3.

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5.0 VERIFICATION AND SUBMISSIONS

5.1 Submissions

5.1.1 Mill Certification

Prior to putting the reinforcement on site, provide mill certificate to confirm that each batch ofsteel and mesh supplied to the site complies with SS 2, SS 18 or SS 32 asappropriate. Include also information such as country of origin and the name ofsupplier for review.

5.1.2 Details of Welding Works

Submit full details of welder’s qualifications, welding procedures and joint details foracceptance prior to carrying out the works if required for the project.

5.2 Sample Tests

Carry out the following tests in an approved laboratory on every batch of reinforcementdelivered to site. Testing requirements and frequency to be in accordance with SS 2for reinforcement bars and SS 32 for welded steel fabric.

a. Tensile test

b. Bend and Re-bend test

c. Weldability test