Kuliarchar Sweater Industries Ltd.

Transcription

1 Kuliarchar Sweater Industries Ltd. Bada Kalmasher, K.B bazar, Gazipur, Bangladesh ( , ) 9 March 2014 DEA 1

2 2 Observations Made

3 3 High Stress in Columns

4 Cursory calculations indicate that internal and external columns working stress is at a high level in Buildings A and B. A Detailed Engineering Assessment of the building is required (See attached Scope). Engineer is to perform detailed calculations based on as constructed dimensions and concrete tests to prove column size is adequate. High Stress in Columns 4

5 5 Double Height Columns

6 Double height columns in Building B are open to high impact loads from vehicles Double Height Columns 6 One double height column in Building A has some form of vehicle impact prevention measure, but not all.

7 7 Construction of new Concrete Roof in Building A to replace the Existing Steel Roof

8 Construction on the roof 8 On the roof of Building A, work has commenced to remove the steel dining area and replace it with a concrete roof.

9 9 Water Tanks on the Roof

10 2.0m 2.5m 2.5m High water tank placed on the roof of building A. This places a significant load into the columns. Building A 2.0m High water tank placed on the roof of building B. This places a significant load into the columns. Water Tanks on the Roof 10 Building B

11 11 Hairline Cracks in Beams

12 Hairline cracking was observed at mid-span of the supporting beams under the 5 th floor. These are a result of normal structural behaviour of 2-way spanning slabs and supporting beams. Hairline Cracks in Beams 12

13 More cracks in various beams supporting the 5 th floor slab. Hairline Cracks in Beams 13

14 14 Hairline Cracks in Slabs

15 Cracking was observed over the beams on the grid lines on the 4th Floor level of Building A. These are a result of normal structural behaviour of 2- way spanning slabs and supporting beams. Hairline Cracks in Slabs 15

16 16 Deflection in Beams

17 A small number of beams at 6th floor level of Building B, with typical span of 5.4m, appear to have deflected. However, no associated cracking was observed. It is possible that the render may have been poorly applied to give this apparent deflection. Deflection in Beams 17

18 18 Semi Circular Cantilever Areas

19 Minor cracking on one element suggests a small deflection in one cantilever. Cantilever slabs acting compositely with upstand/downstand concrete wall elements constructed on a semi-circular plan shape. In two areas, part of the upstand/downstand has been broken out to facilitate linking walkways connecting Buildings A and B. This has weakened the construction but may be acceptable subject to a detailed design check. Semi Circular Cantilever Areas 19

20 20 Priority Actions

21 Problems Observed 1. High Stress in Columns in Buildings A and B 2. Double Height Columns to Front of Both Buildings 3. Construction of Concrete Roof of Building A currently under way 4. Apparent Deflections/Cracking of Beams at 5 th /6 th Floors 5. Retrofitted Connecting Walkways Part of Concrete Upstand/Downstand Structure Removed 21

22 Item No. Observation Recommended Action Plan Priority 1 High Stress in Columns in Buildings A and B Maintain current use of the floors and don t change use or increase occupation, either of which could increase loading. Floor loadings throughout shall not exceed 1.5 kn/m2 until DEA confirms a greater floor live load allowance is permissable. Immediate - Now 2 3 High Stress in Columns in Buildings A and B High Stress in Columns in Buildings A and B Building Engineer to review design, loads and columns stresses in all columns. A Detail Engineering Assessment of Factory to be commenced, see attached Scope. Immediate - Now Immediate - Now 4 High Stress in Columns in Buildings A and B Produce and actively manage a loading plan for all floor plates within the factory giving consideration to floor capacity and column capacity. 6-weeks 5 High Stress in Columns in Buildings A and B Detail Engineering Assessment to be completed 6-weeks High Stress in Columns in Buildings A and B High Stress in Columns in Buildings A and B High Stress in Columns in Buildings A and B Verify in-situ concrete stresses either by 100mm diameter cores or existing cylinder strength data for cores from 4 columns. Continue to implement load plan Implement strengthening measures if required following the findings of the DEA 6-weeks 6-months 6-months 22

23 Detail Engineering Assessment This Schedule develops a minimum level of information, Analysis and testing expected as part of a Detail Engineering Assessment. The Building(s) have been visually assessed and it is deemed necessary that a detailed engineering assessment be carried out by a competent Engineering Team employed by the factory Owner. This Request should be read in conjunction with the BUET developed Tripartite Guideline document for Assessment of Structural Integrity of Existing RMG Factory Buildings in Bangladesh (Tripartite Document), the latest version of this document should be referenced. T his document also gives guidance on required competency of Engineering Team. We expect that the following will be carried out: 1. Development of Full Engineering As-Built Drawings showing Structure, loading, elements, dimensions, levels, foundations and framing on Plan, Section and Elevational drawings. 2. The Engineering team are to carry out supporting calculations with a model based design check to assess the safety and serviceability of the building against loading as set out in BNBC-2006, Lower rate provisions can be applied in accordance with the Tripartite Guidelines following international engineering practice, justification for these lower rate provisions must be made. 3. A geotechnical Report describing ground conditions and commenting on foundation systems used/proposed. 4. A report on Engineering tests carried out to justify material strengths and reinforcement content in all key elements studied. 5. Detailed load plans shall be prepared for each level showing current and potential future loading with all key equipment items shown with associated loads. 6. The Engineering team will prepare an assessment report that covers the following: As-Built drawings including Plans at each level calling up and dimensioning all structural components Cross sectional drawings showing structural beams, slabs, floor to floor heights, roof build-ups and Basic design information of the structure Highlight any variation between As-built compared to the designed structure Results of testing for strength and materials Results of geotechnical assessment and testing/investigation Details of loading, inputs and results of computer modelling Commentary on adequacy/inadequacy of elements of the structure Schedule of any required retrofitting required for safety or performance of Structure Any proposals for Retrofitting to follow guidance developed in the Tripartite Document 23

24 Item No. Observation Recommended Action Plan Priority 9 Double Height Columns to Front of Both Buildings As part of the Detail Engineering Assessment required under Item 1, the double height columns at the front of both Buildings A and B shall be assessed. Vehicle impact to be considered, as well as considering the columns as key elements of structure. Immediate - Now Double Height Columns to Front of Both Buildings Double Height Columns to Front of Both Buildings Double Height Columns to Front of Both Buildings Complete DEA and identify strengthening measures where required Complete construction of bracing/strengthening measures (if required) Construct column impact protection to protect from vehicle collision. 6-weeks 6-months 6-months 13 Construction of Concrete Roof of Building A currently under way Construction on the roof of Building A to stop immediately until the Detail Engineering Assessment outlined in Item 1 is complete. Immediate - Now 14 Construction of Concrete Roof of Building A currently under way Capacity of existing columns to carry the additional dead and live loads due to the new concrete roof to be confirmed. 6-weeks 15 Construction of Concrete Roof of Building A currently under way Implement strengthening measures if required. 6-months 24

25 Item No. Observation Recommended Action Plan Priority Apparent Deflections/Cracking of Beams at 5th/6th Floors Apparent Deflections/Cracking of Beams at 5th/6th Floors Apparent Deflections/Cracking of Beams at 5th/6th Floors Apparent Deflections/Cracking of Beams at 5th/6th Floors Retrofitted Connecting Walkways Part of Concrete Upstand/Downstand Structure Removed Retrofitted Connecting Walkways Part of Concrete Upstand/Downstand Structure Removed Retrofitted Connecting Walkways Part of Concrete Upstand/Downstand Structure Removed Retrofitted Connecting Walkways Part of Concrete Upstand/Downstand Structure Removed Remove plaster in cracked/deflected areas to ascertain if the apparent problems are manifested in the underlying structure. As part of the DEA required for Item 1, assess if remedial strengthening work is necessary based on the results of the opening up exercise. Monitor cracks and displacements of the beams to identify if the cracking/deflections are getting progressively worse. Implement strengthening measures where required. As part of the DEA required under Item 1, analyse the impact of removing part of the curved concrete structure to allow the walkways to pass through above and below the slab (see page 19). Remove plaster in cracked areas to ascertain if cracks are reflected in the underlying structure. Identify if strengthening measures in the concrete structure are required in the area of the walkways. Implement strengthening measures where required. Immediate - Now 6-weeks 6-months 6-months Immediate - Now Immediate - Now 6-weeks 6-months 25