SPECIFICATION FOR

CUSTOMER

NAOC

PLANT LOCATION

NAOC PH BASE - NIGERIACode:3217.46.BASG.36913

PROJECT/UNIT

NEW PORT-HARCOURT BASE POWER GENERATION PROJECTPage 1 of 14Rev

0

SPECIFICATION FOR

STRUCTURAL STEELWORK ERECTION

AT

NAOC PORT-HARCOURT BASE, NIGERIA

21/06/120Issued for ReviewH. DORDORD. AKANOR. OMIETIMI

DateRevDescription of RevisionPreparedCheckedApproved

CONTENTS

41. GENERAL

1.1SCOPE41.2.Codes and Standards41.2.3.British Standards41.2.4.Project Specifications42. EXISTING SERVICES AND INSTALLATIONS53. ACCURACY OF ERECTED STEELWORK53.1Erection Method Statement53.2Plant and Equipment53.3Provision of Setting-Out Lines63.4Foundations63.5Handling and Storage63.6Damaged Steelwork73.7Column Base Plates and Slabs73.8Grouting73.9Temporary Restraints until Permanent Features are Built73.10Other Temporary Restraints used by Erection Contractor83.11Erection Loads83.12Lining and Leveling83.13Field Holes93.14Site Welding93.15Bolt/Nut Combinations93.16 Differing Bolt Diameters and Grades93.17 Bolt Length93.18Washers103.19Taper Washers103.20Flooring104. ERECTION FIT104.1Fit-Up104.2Reaming114.3Flame Cutting115PERMISSIBLE DEVIATIONS115.1Position115.2 PLUMB125.2Definitions136. TOUCH-UP PAINTING137.ERECTION QUALITY CONTROL13

1. GENERAL

1.1 SCOPE

This specification defines the requirements for the erection of structural steelwork for the New Port-Harcourt Base Power Generation Project, including equipment support structures, access platforms, and buildings.

1.2. Codes and Standards1.2.1All work shall conform to the latest requirements of the Standards as listed in this specification and any local related statutory regulations. In case of conflict between the various Codes and Standards, or codes and standards and/or this Specification, reference shall be made back to the Company for resolution.1.2.2Unless specified otherwise, the international system of metric units (S.I.) shall be used.

1.2.3. British Standards

BS 3692:1967

ISO Metric Precision Hexagon Bolts, Screws and Nuts

BS 5531: 1988Code of Practice for Safety in Erecting Structural Frames

BS 5950: Pt 2: 1992Structural Use of Steelwork in Building

Specification for Materials, Fabrication Erection Hot Rolled Sections

1.2.4. Project Specifications

3217.44.BASG.35904Specification for Structural Steelwork, Materials and Fabrication

2. EXISTING SERVICES AND INSTALLATIONS

The location of all services above and below ground shall be identified and all reasonable precautions taken to prevent damage to them. No props or supports shall be attached or fixed to such services.

3. ACCURACY OF ERECTED STEELWORK3.1 Erection Method Statement

A method statement, giving details of the erection sequence and techniques, cranage, laydown area, etc., shall be submitted for approval by the Company thirty days prior to commencement of field erection. All erection shall be supervised by competent trained craftsmen fully experienced in erecting structural steelwork.

The Erection Contractor shall be fully responsible for all safety aspects, including training of personnel, provision of general and specialist safety equipment and temporary staging, scaffolding, handrailing, etc. All temporary staging etc. shall be fully inspected and certified prior to and during its use. All permanent access ways, handrails, etc. shall be certified as being safe to use prior to allowing temporary or permanent access which shall be constantly monitored for condition and safety whilst the Erection Contractor is responsible for the work area.

3.2 Plant and Equipment

3.2.1All erection plant and equipment shall be suitable and of sufficient capacity to safely

complete erection of the steelwork to the contract schedule.

3.2.2 All construction plant and equipment shall conform to the requirements of statutory regulations applicable to construction plant and lifting devices. Test certificates for such items as slings and brothers shall be available for inspection.

3.3 Provision of Setting-Out Lines

The Erection Contractor shall provide setting-out lines and datum levels within, or immediately adjacent to, the Works prior to the commencement of erection. Datum and setting-out lines shall be transferred from the site survey monuments.

3.4 Foundations

The Erection Contractor shall inspect the prepared foundations and holding down bolts for position and level not less than seven days before erection of steelwork starts. Any discrepancies which are outside the deviations specified in Section 5.0 shall be corrected by others before erection commences.

3.5 Handling and Storage

3.5.1All materials shall be stored well clear of the ground, on skids or timbers. These supports shall be spaced so that no damage results from deflection. Stacking of components more than three pieces high shall not be permitted.

3.5.2. Steelwork components shall be handled and stored in such a manner as to minimise the risk of surface abrasion and damage.

3.5.3.Fasteners and small fittings shall be stored in dry conditions.

3.5.4.Particular attention shall be given to sorting and storing by colour codes, structures, areas erection programme etc. The steelwork shall be arranged so that the colour code and the member mark are clearly visible. The colour coding system will be advised on Award of Contract.

3.5.5. Additional member marks shall be provided in the event that a particular stacking arrangement renders the original colour code and member mark invisible.

3.6 Damaged Steelwork

Any steelwork damaged during off-loading, transportation or storage shall be restored to conform to the standards of manufacture as given in this Specification and other related specifications, as soon as possible after the damage has been identified. If the paintwork only is damaged this may be left and rectified with the touch-up painting after erection.

3.7 Column Base Plates and Slabs

3.7.1Steel packings shall be supplied to allow the structure to be properly lined and levelled and of sufficient size to avoid local crushing of the concrete.

3.7.2. Base packings shall be placed so that they allow subsequent grouting to completely fill all

spaces directly under the base plates.

3.7.3. Base packs may be left permanently in place only by prior agreement of the Company.

3.8 Grouting

3.8.1Grouting shall not be carried out under column base plates until a sufficient portion of the structure has been aligned, leveled, plumbed and adequately braced. No grouting shall take place until the Company has approved the erected steelwork.

3.8.2. Immediately before grouting, the space under base plates shall be clean and free of all extraneous matter.

3.9 Temporary Restraints until Permanent Features are Built

3.9.1The Erection Contractor is responsible for the stability of the structure during its erection.

3.9.2. The bracing shown on the design drawings has been designed to provide a stable structure upon the completion of erection. As each level is erected, the permanent bracing shall be installed in conjunction with the framing at that level to improve the stability of the partially erected structure.

3.10 Other Temporary Restraints used by Erection Contractor

3.10.1The Erection Contractor shall design and install all additional temporary bracing or guying required to meet loadings imposed during erection, consistent with the erection sequence used, or required at the end of any work period, to ensure safe and stable conditions.

3.10.2. If the Erection Contractor uses temporary restraints during erection which do not substitute for permanent features, they may be removed after the structure has been lined, leveled and plumbed provided that sufficient steelwork and/or permanent bracing has been erected to ensure the stability of the structure.

3.11 Erection Loads

3.11.1The Erection Contractor shall ensure that no part of the structure is permanently distorted by stacking of materials or temporary erection loads during the erection process.

3.11.2. No equipment shall be supported from the frame until correct position and alignment has been obtained and the structure is securely connected to its foundations and grout has achieved a crushing strength of 10 N/sq.mm.

3.12 Lining and Leveling

3.12.1Each part of the structure shall be aligned as soon as possible after it has been erected. Permanent connections shall not be made between members until sufficient sections of the structure have been aligned, levelled, plumbed and temporarily connected to ensure that members will not be displaced during subsequent erection or alignment of the remainder

of the structure.

3.12.2. In the case of multi-storey structures, the steelwork up to the first column splice level shall be plumbed, aligned, levelled, permanently bolted up with all bracing in position, and column bases grouted up and anchor bolts tightened, before proceeding above that level.

3.13 Field Holes

Any holes required in the field shall be made by drilling, and no burning or punching shall be permitted unless authorised by the Company in writing.

3.14 Site Welding

Steelwork shall only be site welded when specifically called for on the construction drawings, in which case it shall comply with the relevant requirements of Specification 3239.04.DAST.33004 Materials and Fabrication.

Unless directed otherwise, no site welding shall be permitted on structural steelwork which has received a special surface preparation or painting.

3.15 Bolt/Nut Combinations

3.15.1The combination of bolts and nuts shall be in compliance with that specified.

3.15.2 Any bolt assemblies which seize when being tightened shall be replaced.

3.16 Differing Bolt Diameters and Grades

Different grade bolts of the same diameter shall not be used in the same structure, except for holding down bolts.

3.17 Bolt Length

The bolt length shall be chosen such that at least one thread plus the thread run-out will be clear between the nut and the unthreaded shank of the bolt after tightening, and at least one clear thread shall show above the nut.

3.18 Washers

3.18.1When the members being connected have a surface protective treatment, a washer shall be placed under the nut or bolt head being rotated.

3.18.2 A suitable plate washer shall be used under the head and nut when bolts are used to assemble components with oversize or slotted holes.

3.19 Taper Washers

3.19.1When the bolt head or unit is in contact with a surface which is inclined at more than 3 from a plane at right angles to the bolt axis, a taper washer shall be placed to achieve satisfactory bearing.

3.19.2. Galvanised or sheradised nuts shall be checked after being galvanised or sheradised forfree running on the bolt, and re-tapped if necessary to ensure a satisfactory tightening performance.

3.20 Flooring

Grating shall be erected in proper sequence with the structural steel so as to make temporary flooring unnecessary.

4. ERECTION FIT

4.1 Fit-Up

Connected parts shall be firmly drawn together. If there is a remaining gap which may affect the integrity of the joint, it shall be taken apart and a pack inserted.

4.2 Reaming

Where parts cannot be brought together by drifting without distorting the steelwork, rectification may be made by reaming, provided the design of the connection will allow for larger diameter holes and bolts, and is authorised by the Company in writing.

4.3 Flame Cutting

4.3.1Field correction of structural steelwork by flame cutting shall not be permitted without prior authorisation.

4.3.2 Undimensioned openings shown on the erection drawings in floor plate or grating shall be flame cut and have toe plates or banding supplied and field welded by the Erection Contractor.

5 PERMISSIBLE DEVIATIONS

The erection of steel-framed structures shall be controlled in such a way that the following Permissible Deviations (PD) for the completed structure are not exceeded:

5.1PositionP.D. (mm)

a)Permissible deviation between designed and actual position of any erected column at base.+ 5

b)Overall plan dimensions deviation in length or width

True overall dimension L

For L < 30m

For L > 30m

20

20 +

0.25(L-30)

where

L is in m

5.2 PLUMB

P.D. (mm)

Vertical permissible deviation above base of column:

Structure up to 6m high

Structure above 6m and up to 10m high

Structure above 10m and up to 20m high

Structure above 20m high+ 5

+ 10

+ 15

+ 20

5.1 LEVELS

Unless otherwise specified, the level of a beam shall be taken as the top of the upper flange:

P.D. (mm)

a)Permissible deviation between designed and actual levels of the base of any column to be erected.+ 3

b)Permissible deviation between designed and actual levels of any beam at the junction with the column:

When the beam is up to 6m from grade

When the beam is above 6m and up to 10m from grade

When the beam is above 10m from grade.+ 5

+ 8

+ 12

c)Notwithstanding the above, the maximum difference between levels at the ends of a beam shall be:

For length of beam up to 6m between column centres

For length of beam above 6m and up to 10m between column centres

For length of beam above 10m between column centres.+ 4

+ 6

+ 8

5.2 Definitions

a) Designed position is that position given by the dimensions and co-ordinates on the drawings issued for construction.

b) Actual position is the final erection position and shall be determined from survey monuments.

c) Designed level is that level given on the drawings issued for construction.

d) Actual level is the final erected position and shall be determined from agreed benchmarks.

e) All actual levels at a floor or equipment level (including ground level) within a structure shall be measured from one transferred bench mark.

f) In structures where movements due to temperature change are considerable, the PDs listed above will apply at the mean position of the member being checked.

6. TOUCH-UP PAINTING

After complete erection, surfaces where paint was omitted for field welding, and all areas damaged subsequent to shop painting shall be repaired

Paint shall only be applied when surfaces are dry and the temperature of the surface metal exceeds 5C.

Any damage caused, during delivery and/or erection to galvanised steel surfaces shall be touched-up with zinc rich paint after thorough surface cleaning.

7. ERECTION QUALITY CONTROL

The Erection Contractor shall establish a field inspection system to perform sufficient inspections and tests to ensure conformance to Contract requirements. The Erection Contractors Quality Control procedures shall be subject to authorisation by the Company prior to start of the work.

This document is company property. NAOC Ltd. lawfully reserves all rights. Any unauthorized attempt to reproduce it, in any form, is strictly prohibited.