rectification on horizontal cracked column

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CORRECTIVE ACTION FOR THE HORIZON-TAL CRACKED CRANE CORBEL, INSIDE

COMPRESSOR BUILDING UNIT 3.EPCC FOR SEGAMAT COMPRESSOR STATION EXPANSION PROJECT

CLIENT:

PETRONAS GAS BERHAD (PGB)

PROJECT TITLE:

ENGINEERING PROCUREMENT CONSTRUCTION AND COMMISSIONING (EPCC) FOR SEGAMAT COMPRESSOR

STATION EXPANSION PROJECT

DOCUMENT TITLE:

PROPOSED CORRECTIVE ACTION FOR THE HORIZONTAL CRACKED CRAND CORBEL, INSIDE

COMPRESSOR BUILDING UNIT 3

CONTRACT NO:PGB/HO/20/2005/0031

CONTRACTOR PROJECT NUMBER:8023

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TABLE OF CONTENTS

1.0 SITE OBSERVATIONS

2.0 GROUT TYPE MATERIALS

3.0 SURFACE PREPARATION

4.0 FORMWORK

5.0 MIXING GROUTS

6.0 MIXING GUIDELINES

7.0 CURING

8.0 TESTING PROCEDURE

9.0 ATTACHMENTS

ATTACHMENT 1 – AFC DRAWINGS - E12320 PAGE 1/1 REV. A- E12320-V1 PAGE 1/1- 8023-SG-DR-ST-116 REV. 0- 8023-SG-DR-ST-117 REV. 0

ATTACHMENT 2 – DEFECTIVE AREA PHOTO

ATTACHMENT 3 – PROPOSED CORRECTIVE ACTION DRAWING

ATTACHMENT 4 – PROPOSED GROUT MATERIALS:- FOSROC MANUFACTURERS TECHNICAL DATA SHEET

1.0 SITE OBSERVATIONS

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The corbels were connected to column with a total height of 980 mm. The column cross-section

dimensions were 500 x 500 mm. A total of eight numbers of corbels have the same dimensions and

reinforcement bars detailing, as shown in sketch drawing attached. The flexural reinforcement consisted

of four deformed bars each of diameter 25 mm with six links horizontal closed stirrups of diameter 12

mm and one no of 20 mm diameter. The corbels and columns have been casting together using wooden

formwork. Please refer to AFC Drawing No. 8023-SG-DR-ST-117 Rev. 0 attached.

All round of vertical surfaces of corbel found no defect even hair crack occurred. The cracked only

occurred between TOC of corbel and the 90mm thick of grout with the maximum gap of 7 mm. The

longitudinal beams (main girders) are resting on corbels in good condition, which are connected to

columns and remain stable. Therefore, the cracked has been justified as no major defect and the

overhead crane is safe to use to carry the maximum save working load 12 tones. Refer to attached AFC

drawing no. E12320, page 1/1 Rev. A.

However, the horizontal cracked on the corbels need to rectify immediately due to long term period

usage of the overhead crane.

2.0 GROUT TYPE MATERIALS

The type of grout to be applied has been selected as describes in Table 1 below according to the advised

given by the Grouting Specialist System based on observation at site. These selected materials are

suitable for the specific applications especially those grout to be used are subject to high operating

temperatures and aggressive environments.

Table 1: Grout Type Application and Proposed Products

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TYPICAL APPLICATION PROPERTIES REQUIRED PROPOSED PRODUCTS

Plant, equipment and structural members subject to very high dynamic loads, vibration high temperature operation and/or chemical attack eg: crushing and screening equipment, generators, turbines, crane rails, anchor bolts, equipment sole plates bolt holes and chocks

Highly flowable solvent free polymer resin system with very high early and ultimate strengths, high temperature and chemical resistance and low creep characteristics.

FOSROC :

Conbextra EP 10 0.25-10mm thickness, or Conbextra EP 40 10-40mm thickness, orConbextra EP 65 35-65mm thickness, or Conbextra EP 120 < 120mm thickness, orConbextra GP. andConcure WB 30 for compound curing.

Note: For more details, refer to Manufacturer’s Technical Data Sheet attached.

All materials shall be supplied in a ready to use form requiring only mixing. No additional materials,

(sand, cement etc.), shall be added without the approval of the QC Inspector. All materials shall be

mixed and placed in accordance with the manufacturer’s instructions.

3.0 SURFACE PREPARATION

Surfaces shall be prepared in accordance with Sections 3.0 and 5.0 of Structural Concrete Rectification

Works Procedure – 8023/PSP/CON/24. Between surface preparation and placement of grout, the

prepared area shall be protected from contamination. The QC Inspector shall approve the surface

conditions immediately prior to the placement of the grout.

All defective concrete, laitance, dirt, oil grease, liquid and foreign substances shall be removed by

mechanical means prior to grouting. The surface shall be left clean, sound and reasonably rough to

ensure a good bond. Just before grouting, all free water shall be removed, particularly from chipped

surface area and block outs, by sponging or by blowing out with oil-free, dry compressed air.

4.0 FORMWORK

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If the existing defected grout need to be removed entirely, formwork may be used to facilitate rapid,

continuous and complete filling of the space to be grouted. It shall be substantial, secured, well braced

and sealed to withstand grout pressure under working conditions and prevent leakage. Formwork shall

be coated with a concrete release agent to facilitate easy removal later.

5.0 MIXING GROUTS

Mixing procedures shall be in accordance with the Manufacturer’s instructions for the selected grout

type product. Refer to Manufacturer’s Technical Data Sheet Attachment.

The grout head shall be maintained daily so that a continuous grout front is achieved. Alternate methods

of grout placement can be used subject to the approval of the QC Inspector.

6.0 MIXING GUIDELINES

Materials shall be mixed as close as possible to locations to be grouted, using a paddle type mortar

mixer until a homogeneous, uniform mixture is obtained. Smaller quantities shall be mixed using a slow

speed drill, (max. 600 rpm), fitted with a suitable mixing paddle to avoid air entrapment and not by

hand.

The addition of more water than the maximum specified by the Manufacturer’s specification will reduce

the strength of this type of grout and cause shrinkage and consequently, shall not be permitted.

The mixed grout shall be transported to the specific grout location without delay. Grout shall not be re-

tempered or worked after the initial set has taken place. Unused batches that have begun to set or any

grout that has been damaged during transit shall be discarded. During hot weather, precautions shall be

taken to ensure that all grouting materials, concrete substrates and steel surfaces to be grouted, are

maintained at temperatures below 30°C prior to, during and for 48 hours after the grout placement.

7.0 CURING

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No wet curing or curing compounds are required if using flowable method and the gap thickness is

small. However, if trowellable method or wide surface dimension required, upon completion of

grouting, the grout shall be cured with an approved membrane curing compound applied in accordance

with the manufacturer’s instructions.

8.0 TESTING PROCEDURE

Prior to grouting and as directed by the QC Inspector, samples of the type of grout to be used shall be

taken. The consistency of the mix to be sampled shall be identical to that required for the actual

grouting operation. The size and number of samples taken and tested shall be in accordance with the

relevant Standard and Test Method which is 50mm x 50mm x 50mm dimension. The grout to be tested

for flowable consistency, refer to FOSROC Manufacturer’s Technical Data Sheet for details.

Finally, after the rectification work has been done, all surfaces shall be grinded flashing with existing

column surface and followed by repainting work to the defected area.

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ATTACHMENT 1 – AFC DRAWINGS - 8023-SG-DR-ST-116 REV. 0- 8023-SG-DR-ST-117 REV. 0

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ATTACHMENT 2 – DEFECTIVE AREA PHOTO

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ATTACHMENT 3 – PROPOSED CORRECTIVE ACTION DRAWING

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ATTACHMENT 4 – PROPOSED GROUT MATERIALS:- FOSROC MANUFACTURERS TECHNICAL DATA SHEET

rectification on horizontal cracked column

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