S B Design Ltd. Famous Design Ltd. 246/1/F, West Agargaon, Sher-E-Bangla Nagar, Dhaka-1207 ( N, E) 17 February 2015

Transcription

1 1 S B Design Ltd. Famous Design Ltd. 246/1/F, West Agargaon, Sher-E-Bangla Nagar, Dhaka-1207 ( N, E) 17 February 2015

2 2

3 High stress levels in columns 3

4 North Building South Building Cursory calculation on few typical columns for the both (North and South) buildings shows that the columns have high level of stress 4

5 Heavily-loaded areas 5

6 Box storage loads on 2 nd Floor (North Building) Cloth storage loads on 4 th Floor (North Building) 2 nd Floor Box storage 4 th Floor Cloth storage 6

7 South Building South Building 7 North Building South Building North Building

8 Toilet on the cantilever slab Cardboard storage on the cantilever slab 8

9 Loads from toilet build-up areas in North Building 9

10 Estimated Weight of the Boiler : kn Boiler at 2 nd floor (North Building) Loads from Boiler machine on the cantilever 10

11 Cracking in column at construction joint 11

12 This is a brick wall with small columns which was most probable part of the previous façade. On the ground floor this wall is not present. Head of column and beam connection to be investigated, and remedial structural works carried out as required. The movement joint is shown in red and the column in yellow. 12

13 Discrepancies between drawings and on-site observations 13

14 North Building North Building South Building South Building Initial permit drawing shows two buildings. Currently the two buildings are connected and there is a construction joint. South Building 14

15 Columns are not on grid North Building 15 South Building Cantilever is not shown in drawing Layout as observed on site

16 16 Damage to 1 st floor beam, and cracks in the Buildings

17 Damage to soffit of 1 st floor beam to be investigated, and structural repair to be made as required. Analyse the impact of the previous façade wall which is above that soffit. 17

18 18 Additional structures were built on the construction joint. Due to the differential movements between the two buildings, cracks are observed throughout the buildings in the construction joint area.

19 Crack in brick wall due to Cantilever 19

20 Crack on 5 th floor (South Building) 20 Possible Shrinkage crack on 5 th floor Possible Shrinkage crack on 5 th floor

21 Non-engineered lightweight steel roof structures 21

22 Non-engineered Steel Roofs to Dining (North Building) 22

23 23 Construction joint between the buildings

24 South Building North Building North Building North Building South Building South Building Construction joint between the North and South Building Construction joint on 1 st floor 24

25 Non-permitted additional rooftop structures 25

26 Water tank Storage Kitchen Dining South Building North Building 26 Non-permitted additional structures

27 Problems Observed 1. High stress levels in the columns 2. Heavily-loaded areas 3. Cracking in column at construction joint 4. Discrepancies between the permit drawings and the as-built structure 5. Damage to 1 st floor beam, and cracks in the Buildings 6. Non-engineered lightweight steel roof structures to stair cores. 7. Construction joint between the buildings 8. Non-permitted additional rooftop structures 27

28 Item No. Observation Recommended Action Plan Recommended Timeline 1 High stress levels in columns Building Engineer to review design, loads and column stresses in all columns for both North and South buildings. Immediate - Now 2 High stress levels in columns Verify in-situ concrete stresses by 100mm dia. cores from 4 min. columns in each building. Immediate - Now 3 High stress levels in columns A Detail Engineering Assessment of both Buildings to be commenced, see attached Scope. Immediate - Now 4 High stress levels in columns Live loads to be limited to 1.5kPa at all levels, pending outcome of Detail Engineering Assessment Immediate - Now 5 High stress levels in columns Detail Engineering Assessment to be completed 6-weeks 6 High stress levels in columns Produce and actively manage a loading plan for all floor plates within the Buildings, giving consideration to floor capacity and column capacity. 6-weeks 7 High stress levels in columns Actions identified in the Detail Engineering Assessment to be implemented. 6-months 8 High stress levels in columns Continue to implement the load management plan. 6-months 28

29 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 Elevation 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 29

30 Item No. Observation Recommended Action Plan Recommended Timeline 9 Heavily-loaded areas Pending the outcome of the Detail Engineering Assessment (see Item 1), live load in cantilevers and either side of construction joint to be limited to 1,5 kpa at all levels. Immediate - Now 10 Heavily-loaded areas As part of the Detail Engineering Assessment (see Item 1), Building Engineer to confirm design loading of slabs and incorporate it into the loading plan for all floor plates within the Building. 6-weeks 11 Heavily-loaded areas Continue to implement the load management plan 6-months 12 Cracking in column at construction joint As part of the Detail Engineering Assessment (see Item 1), Building Engineer to investigate top of column and beam connections. 6-weeks 13 Cracking in column at construction joint Carry out any remedial structural works arising from investigation. 6-months 14 Discrepancies between permit drawing, design drawings and as-built structure As part of the Detail Engineering Assessment (see Item 1), Building Engineer to survey the as-built structure, including as-built floor finish thickness. 6-weeks 15 Discrepancies between permit drawing, design drawings and as-built structure Building Engineer to produce accurate as-built drawings. 6-months 30

31 Item No. Observation Recommended Action Plan Recommended Timeline 16 Damage to 1st floor beam, and cracks in the buildings Building Engineer to investigate damage to beam and cracking, and determine cause. 6-weeks 17 Damage to 1st floor beam, and cracks in the buildings As part of the Detail Engineering Assessment (see Item 1), Building Engineer to carry out full design check of all floor slabs and beams to confirm their load capacity, taking into account the cracking. 6-weeks 18 Damage to 1st floor beam, and cracks in the buildings Carry out any structural repairs as necessary to beams and slabs. 6-months 19 Non-engineered lightweight steel structures As part of the Detail Engineering Assessment (see Item 1), Building Engineer to carry out full design check on lightweight steel roofs and the support and connections to the main building structure to assess their capacity to withstand code vertical and wind loads. 6-weeks 20 Non-engineered lightweight steel structures Reconstruct or repair lightweight steel roofs as necessary to ensure their adequacy to withstand code vertical and wind loads. 6-months 31

32 Item No. Observation Recommended Action Plan Recommended Timeline 21 Remedial work to the construction joint between the buildings As part of the Detail Engineering Assessment (see Item 1), Building Engineer to assess the design and detailing of the construction joint. 6-weeks 22 Remedial work to the construction joint between the buildings Carry out any remedial structural and finishing works arising from the engineering assessment, including any measures required at roof level to ensure the joint is watertight. 6-months 23 Non-permitted additional rooftop structures As part of the Detail Engineering Assessment (see Item 1), Building Engineer to assess the additional rooftop structures in terms of their own engineering robustness and stability, and also their effect on the supporting structures. 6-weeks 24 Non-permitted additional rooftop structures Repair or remove the additional rooftop structures as directed by the Building Engineer. 6-months 25 Non-permitted additional rooftop structures Carry out any structural works as required to the supporting structures. 6-months 32