04 May2014 Structural Inspection...

Structural Inspection ReportObservations & Actions

Authors: John Flaherty, Billy AllenChecked by: Paddy ButlerApproved by: Peter Flynn

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Chorka Textiles Ltd.Kazirchor,Danga,Plash,Narshingdi

(23.896728 90.573490)04 May2014

Revision: Issue 1Date: 21th May 2014

Category Amber

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Executive summary

On 4th May 2014, Mr John Flaherty and Mr Billy Allen of Arup carried out a visual structural survey of Chorka Textiles Ltd. factory at the address and co-ordinates given on the cover page of this report. We met with Mr Md. Nasiruzzaman (Manager +HR), Ms Eyerin Akter Eyevee (CRS Officer) of NafisaInternational Trading, Engr Md Mosharaf Hossain (COO), Engr Mr Eleash Mridha (Director) of Pran-RFL Group, Mr Md Nazmur Rahman (Asst. Manager), and Mr Moshioun Rahman (Asst. General Manager) of Chorka Textile Ltd. We inspected all accessible parts of the building.

The factory is located in a campus currently comprising 6 buildings. The buildings’ general construction and use are as follows:• Warehouse: 2 storey RC frame and slab (1st floor currently under construction). Storage of materials

and inspection.• Production units 1, 2 and 3 and Facilities Building: Single storey buildings comprising concrete

columns and steel truss roofs with infill rendered brick walls. Unit 1 is used for sewing and finishing; Units 2 and 3 are not in use; Facilities Building include dining, medical, childcare and admin.

• Substation: Single storey RC frame and slab with infill rendered brick walls.• Water treatment plant: Covered with a light steel roof.

Construction of the plant commenced in early 2012 and was completed in 2013, when manufacturing commenced. Construction of the remainder of the warehouse and other buildings will be progressed in the future.

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Executive Summary (continued)

We were shown copies of:• Permit Engineer Drawing dated March 2013, prepared by Engr Indrajit Das and approved by the

Local Authority.• Structural and Architectural drawings dated March 2013 by Property Development Limited.• Sub-soil Investigation Report dated May 2012 by The Science sub-soil engineering.• Process Drawing for the Department of Industry, approved 2013.

The soils report states that the use of isolated shallow footing was not recommended. It does however give a allowable bearing pressure at a depth of 3.0m of 129kPa generally. The footings used were pads at this depth. The drawings also call for soil improvement. Sand was compacted to 120kPa.The structural drawings show concrete columns on pad bases ranging in height from 7m to 9m in the production units, cantilevering to support a steel truss and roof structure. The design engineer confirmed that this was the system employed in the design.

At the close-out meeting, two immediate actions were called for.• A telecoms mast at the front of Building 3 was unsafe and needed to be stayed properly or taken

down • Access to the 1st floor of the warehouse needed to be restricted as there was no guarding at the

slab edge

The information shown on the drawings generally corresponds across each set and with the as-constructed structure in relation to number of bays, general arrangement of cores etc.

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We do have some concerns that need to be addressed within 6 weeks. The principal reason for our concern is the design of the Production Units and facilities unit for lateral load. The immediate concerns are noted above.

A high-level and non-exhaustive list of key concerns are:

• The telecoms mast at the front of Building 3.• No edge protection at first floor of the warehouse - access to be restricted until completion of

building works.• The design for lateral loads within the production buildings. • Design strength of the columns to resist lateral loads in bending.• Documents do not match the as-built in the warehouse• Cracking noted in the wall panels of the warehouse • Concrete internal columns noted off-plumb in production buildings• Non-engineered roofs to the stair wells of the warehouse and over the water treatment plant.• Canopy fixings in the warehouse not properly engineered

We see no reason to suspend operations in the facility due to these concerns (subject to the required actions noted at the end of this report).

No additional construction should be considered until such time as the design issues raised have been addressed.

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Further actions with associated priorities and timeframes are given at the end of this report. Please note that these actions should be completed as soon as practically possible and certainly within the timeframe noted.

We have reviewed the property from an outline seismic perspective and would consider the buildings, along with many others in the Dhaka region, to have a significant risk of damage in a major seismic event.

Our Limitations and Assumptions are also noted at the end of this report.

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Building Extents

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Building Extents

Chorka textiles Ltd. – Factory Site Location

N

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There are six buildings on the Chorka Textiles compound.

Production Buildings 1,2 and 3 • Single storey structures. Building 1 is in operation.

Buildings 2 and 3 are unoccupied.

Warehouse structure• Currently under construction with the ground floor

complete.

Facility building and generator room• Single storey structures, both occupied.

Permit drawings were provided for the buildings, approved by the local authority in 2013.

Structural and Architectural drawings by Property Development Limited March 2013 were made available.

Building Extents

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136

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2

Chorka textiles Ltd. – Factory Site Layout

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WarehouseProduction Unit 1

Production Unit 2

Production Unit 3 Facility Building

Sub Station Building

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136

5

2

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Building Extents


Buildings 1, 2 and 3 – Production Units

Building 6 – Facility Building

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4

136

5

2

10

Building Extents


N

Building 4 – Warehouse

Building 5 – Substation

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Structural Systems

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Buildings 1, 2, 3 and 6 (Production units and facilities buildings)

• Structure: Single storey structures with RC columns 7m and 9m high supporting steel roof trusses supporting a metal deck roof.

• Façade: Rendered brick walls with masonry wind posts and RC lintels supported by RC beams between RC columns.

• Stability System: RC columns assumed to cantilever from the foundations.

• Foundations: Isolated pad foundations indicated on structural drawings.

9m

7m

Truss spanning between RC columns with brick infill panels

Facilities Building

Production Unit Cantilever columns supporting the truss roof

Structural Systems

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Buildings 4 and 5 (Warehouse and Generator shed) and WTP

• Structure: The warehouse is a two storey structure built to first floor level - RC frame with beams and two-way spanning slab. The generator is a small single storey building with a concrete frame and a steel truss roof.

• Building 4 Façade: Rendered brick walls with masonry wind posts and RC lintels supported by RC beams between the RC columns. The cores are currently built to two storeys, as is a platform supporting water tanks.

•

Building 4 Stability System: The RC frame acts to resist horizontal loads in both directions

• Foundations: Isolated pad foundations indicated on structural drawings

Light steel canopy roof over the WTP

Generator Building

Warehouse building 4 RC Frame with rendered brick facade

Structural Systems

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Buildings 1,2 & 3 (Production units) Principal Structure

• Grid: 5.8m x 6.9m max. observed• Eaves Height ~7.0m (typ.) • Apex 9.0m to underside of deck

• Columns: 300mm x 350mm RC (typ. internal).

8.0m

Top of col

Steel roof supported on RC cols

Structural Systems

RC columns with longitudinal tie beams

Typical wall Panel comprising brick wind post and wall panels between RC columns

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Building 4 (Warehouse) Principal structure

• Grid: 6.0m x 6.0m max. observed

• Columns: 300mm x 350mm RC (typ. internal).

• Water tank platform on roof

• Stair core up to first floor

6.0m

6.0m

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Observations

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Stability: lack of obvious restraint of typical building frame

• Concrete columns used throughout buildings on compound, with solid masonry façades.

• For Production and generator buildings, internal RC beams are provided in longitudinal direction only.

• No evidence of bracing or moment connections between outer face of building and internal frame in transverse direction.

• It is unclear how the structure can withstand transverse horizontal loading. Of particular concern are Production Buildings 1 and 3, as the height of the perimeter walls is 7m and therefore subject to high wind forces.

• No bracing provided in shaded region. • Building appears to be unable to resist horizontal

load as indicated

Observations

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Columns out of plumb in Production buildings

• In several columns in both Production Buildings 1 and 3, columns appeared out of plumb. This was also visible in the façade on the eastern face of Building 3.

• This could be due to poor workmanship when the building was being constructed, or due to settlement of the foundations.

Observations

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Cracking in Warehouse and Facility Buildings

• In the warehouse building, cracking was observed at the bottom corner of each of the windows on ground floor.

• A diagonal crack was also noticed on the inside of one of the wall panels on the northern side of the building.

• Some hairline cracking was noticed on the walls of the facility building.• This cracking appeared from visual inspection to be due to settlement.

Warehouse cracking Warehouse cracking

Observations

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Anchorage of canopies in warehouse

• Metal canopies over each of the loading bays in the warehouse.

• Supporting trusses hung from the top where a bracket extended into the building column and was welded to the exposed rebar.

• This support mechanism is inadequate and could be unstable under wind loading/upliftCanopy bracket welded to rebar

weld

Observations

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Documentation

• Four 10,000 litre water tanks on the roof of the warehouse.

• Building Owner advised that in the future this capacity was to increase to 60,000 litres.

• Structural drawings show six 5,000 litres tanks.

• Column head on gridline A1-01 has 9 bars, where the drawing calls for 12 bars.

• Services mast was observed on the roof of toilet block on the southern side of Production Unit 1. This was not present on any of the drawings.

Water tanks on warehouse

Mast structure

Observations

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Non-engineered roof over stairwells in warehouse

A light metal roof was provided over each of the stairwells in the warehouse building. These appeared to be light and non-engineered.

Light section sizes used as purlins

Roof structure welded to exposed rebar in columns

Observations

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Water damage in soffit of 1st floor below water tanks in warehouse

• Under the water tank locations, staining of the soffit of the 1st floor beam was evident.

• During our inspection, there was a significant leak in these tanks. The building owner was notified of this leak and ensured us that this would be rectified.

Water staining

Observations

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Construction security/safety in warehouse

The first floor of the warehouse building is currently under construction. A number of observations were made in relation to construction security/safety. These are:• The lift shaft on ground floor was left open. This should be blocked off.• The stair well was not closed off. Only authorised staff should be allowed to the roof.• No edge protection around perimeter of 1st floor.

These observations should be acted upon immediately.

Lift shaft opening First floor parapet missing

Observations

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Storage in eastern stairwell of warehouse

The stairwell on the northern side of the warehouse building is used for construction material storage.

Observations

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Non-engineered roof over water treatment plant

A roof covering the water treatment plant appears to be non-engineered. The main issues observed are:• No bracing provided to the

structure.• Structure does not appear to

be designed to withstand wind load.

• Section sizes appear to be light.

Observations

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Radio mast is unsecure

• The radio mast located on the Northern side of Production Building 3 is unstable.

• Three cables are currently in place but offer no structural support in their current state.

This mast requires urgent attention.

Observations

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Problems Observed

1. Telecoms mast at the front of Building 3 to be made safe.

2. No edge protection at first floor of the warehouse.

3. Lateral load design for the production buildings.

4. Design strength of the columns to resist lateral loads in bending.

5. Documents do not match the as-built in the warehouse, or show masts.

6. Cracking noted in the wall panels of the warehouse.

7. Concrete internal columns noted off-plumb in production buildings.

8. Non-engineered roofs to the stair wells of the warehouse and over the water

treatment plant.

9. Canopy fixings in the warehouse not properly engineered.

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Priority 1(Immediate - Now)

Item 1 and actionsThe telecoms mast at the front of Building 3 to be made safe.

• The telecoms mast is currently un-restrained. Mast to be restained/stayed or taken down immediately, stayed system to be engineered prior to placement.

Priority 2(within 6-weeks)

• Permit to be sought for mast

Priority 3(within 6-months)

• None

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Item 2 and actions

No edge protection at first floor of the warehouse.

• Restrict access to 1st floor level of the warehouse building until construction is completed



• None

• None

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Item 3 and actionsThe design for lateral loads within Buildings 1 and 3.

• None


• Building Engineer to carry out calculations with a model-based design check to assess the safety and serviceability of the building against loading as set out in BNBC-2006,

• Lateral stability of the production buildings to be part of check. • The lateral stability system to be clearly laid out and member

sizes checked for this loading condition.


• Amend building as required from engineering assessment.

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Item 4 and actionsDesign strength of the columns to resist lateral loads in bending.

• None


• Building Engineer to carry out calculations with a model-based design check to assess the safety and serviceability of the building against loading as set out in BNBC-2006.

• Adequacy of the RC columns in the production units and Facilities building to be part of check.


• None

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Item 5 and actions

Documents do not match the as-built in the Warehouse, or show Masts

• None


• Building Engineer to survey and amend drawings to include alterations to warehouse and additional structures such as the two masts.


• None

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Item 6 and actions

Cracking noted in the wall panels of the warehouse

• None



• Carry out any remedial / strengthening works following engineering investigation.

• Building Engineer to investigate wall panel cracking noted in the warehouse building.

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Item 7 and actions

Concrete internal columns noted off-plumb in production buildings

• None



• Carry out remedial works as required by engineering investigation.

• Building Engineer to investigate the cause and impact of the internal off-plumb RC columns.

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Item 8 and actions

Non-engineered roofs to the stair wells of the warehouse and over the

water treatment plant.

• None



• Implement actions arising from assessment.

• The roofs to the stair wells in the warehouse and the roof over the Water treatment plant to be assessed by Building Engineer.

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Item 9 and actions

Canopy Fixings in the warehouse not properly engineered

• None



• Carry out the above works

• The canopy fixings to the warehouse building have not been properly engineered. Building Engineer to review and make recommendations

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This report is for the private and confidential use of Accord for whom it was prepared together with their professional advisors as appropriate. It should not be reproduced in whole or in part or relied upon by third parties for any use without the express written permission of Arup.

This report can be used in discussion with the supplier or factory owner as a means to rectify or address any observations made. The report is not comprehensive and is limited to what could be observed during a visual inspection of the building.

This Report is not intended to be treated as a generalised inspection and does not cover the deterioration of structural members through dampness, fungal or insect attack, nor does it deal with problems and defects of a non-structural nature. Other non structural aspects of the building such as fire safety have not been assessed in this survey.

Except as otherwise noted, drains and other services were not viewed or tested during our inspection and are therefore similarly excluded from this Report. We have not inspected any parts of the structure which are covered, unexposed or inaccessible and we are therefore unable to report that any such part of the property is free from defect.

External inspection of the façade walls has generally been carried out from ground level only by visual sighting. No opening up works were carried out (except as noted) and we rely on the Architects and Engineers drawings provided to us for our views on concealed parts of the structure and in particular foundations. Strengths of materials and components are untested and we recommend that the factory owners Building Engineer carries out insitu testing over and above those suggested to satisfy themselves with the material strengths and component details.

Recommendations, where given, are for the purpose of providing indicative advice only, are not exhaustive, relate solely to identifying key and obvious structural defects as identified in this presentation, and do not take the form of or constitute a specification for works. We take no responsibility for the works as constructed. This report does not interfere with the factory owners Building Engineers responsibility for the structural performance of this building, The Building Engineer remains fully responsible for the structural adequacy of the building.

This report does not comment in detail on the future seismic performance of the building and only highlights the fact that the building may experience significant damage or collapse in a seismic event along with many others in the Dhaka region.

The observations in this report are based on the Engineering Judgement of the lead surveyor/engineer at the time of the survey. We assume in making these observations that no covering up of faults defects, filling or plastering over cracking or significant repair work has been carried out by the building owner. Any future alteration or additional work by the building owner will void this report.

Survey Limitations and Assumptions

04 May2014 Structural Inspection...

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