Condition Assessment of Group Housing Society Towers

1. Poor construction quality of group housing societies

Large number of group housing societies in Noida and Greater Noida are complaining regarding poor quality of construction. Defects in building structure are a matter of great concern for the flat owners. There has been absence of quality control checks during construction by competent authorities like Noida Authority, Greater Noida Authority etc

This lack of overall construction quality should be given attention by appropriate competent authorities to avoid Shahberi like incidences in future. Following are some of the points of concern:-

• Poor construction quality
• Poor quality of building material
• Chunks of plaster falling off the walls & balconies
• Poor design of expansion joints
• Poor construction quality of lift shaft walls due to which guide brackets become loose, causing elevator vibration
• Waterproofing failures
• Seepage in basement causing damage to load bearing structures like columns and beams
• Improper maintenance standards being followed by Promoters and Apartment Owners Associations

Causes in the defects in construction should be dug up till the tail so that proper remedial actions and preventive measures (repair, refurbishment, waterproofing etc) can be planned. The method of repair, refurbishment and strengthening would depend very largely on the structural scheme and material used for construction of the towers.

This information will decide the technology to be used and amount of funds. For basement seepage damages slab column connection and slab reinforcement are important information required. The technique for strengthening concrete columns depends on the structural drawings and material specifications. We must know in detail about the load distributors before we decide how to refurbish beams and columns.

Objectives of this brief paper

To carryout conditional assessment of towers of group housing societies before taking up repair, refurbishment and upgrading work

To find a cost effective strategy in the context of overall safety of the structure and residents living in the group housing society

What causes building distress?

Inadequacy of design and poor quality of construction and maintenance are therefore the main reasons for the distress seen in group housing societies.

Promoters don’t consistently follow building codes and byelaws in design and in maintaining quality of construction.

Use of unskilled labor and shortcuts taken during construction stages.

Poor quality control checks during construction stages.

Buildings do not satisfy all the safety and serviceability requirements according to the relevant codes of practice

Promoters and Apartment Owners Associations don’t follow proper maintenance standards.

Main steps of condition assessment will be as given below

To get hold of all control drawings, layout drawings, material specifications, and engineering drawings of the group housing society. In case the Association has been formed, it will be the responsibility of the Association to provide these documents.

To get hold of Noida Authority Building Regulations and Directions 2006 and its subsequent amendments. As per Para 26.1 the CEO can and should inspect the execution of any work, without giving prior notice.

Work shall be carried out in full accordance of these regulations and directions. Follow the construction quality standards as per the regulations and guidelines of the UP Government.

To record the damages in all towers, basement, lift shafts and common areas

To assess the extent of distress and to estimate the residual strengths of structural components and the system including the foundation

To assess whether there are deflections in beams and columns?

Is there any failure or design defect in the expansion joints?

Is there any failure in column-beam joint (lack of stirrups etc)?

Is there any column failure, like absence of tiers, buckling of longitudinal bars etc?

Is there any column top failure due to bad joint details etc?

Is there any failure in waterproofing system due to poor material, incorrect design/layout or workmanship?

Are there cracks in RC Beams, Columns, Slabs, Masonry Walls (particularly if the walls are load bearing)?

Is there tilting of Columns or RC Frames anywhere? Are they out of plumb anywhere?

Is there spalling of concrete? Identify and describe the places where concrete has cracked and delaminated from the substrate.

Identify reasons for spalling.

What is the degree of corrosion in RC Beams and RC Columns? Identify and mark all such places of corrosion.

Is there any corrosion in RC Slabs due to lack of control on the cover or for any other reason?

Is there corrosion of embedded steel reinforcement bars? What are the reasons for this corrosion (construction quality, concrete quality, depth of concrete cover, faulty waterproofing, faulty expansion joints, slab column connection, slab reinforcement etc)?

Have the corroded steel bars expanded and exerting stress on surrounding concrete? Evaluate the degree of corrosion in embedded steel at affected places.

Describe various types of cracks and their dimensions in load bearing structures.

Are there diagonal cracks in the beams and any failure at the column tops?

Investigate the concrete quality, concrete strength and degree of deterioration of affected load bearing RC Beams, RC Columns, RC Slabs, Load Bearing Masonry and Non Load Bearing Masonry.

What types of Structural Repairs will be required to bring back the lost strength. Specify separately for Beams, Columns, Concrete Slabs, Load bearing masonry and Non load bearing masonry.

Is there any retrofitting/refurbishing required along with structural repair? Please specify.

What percentage of wall surfaces will require re-plastering/re-cementing?

Recommendations for removal of existing paint from walls of all towers and buildings and fresh repainting of entire structure and basement.

Examination of rooftop slopes and ways of waterproofing the rooftop surface of all towers, to stop seepage damage.

What BIS Standards should be followed for repair of above mentioned defects?

Information and documents needed for investigation

AOA to provide complete list of defects which have been submitted to NCDRC in our legal case against the Promoter. This list must be given to all the Assessors who will be invited to submit Technical Bids.

Complete record of design details of all towers, basement and common areas.

Architectural details

Construction details and drawings, including details of materials used.

Geotechnical details of the foundation

Identification of alterations (if any) done by Promoter but not shown in approved drawings. This is required to verify the accuracy of original approved drawings vis-à-vis actual construction (as built drawings). Details of such deviations will be recorded.

Details of the usage of the towers including loads

Details of any repair or retrofitting done from the time of getting Occupation Certificate

Evaluation of safety against the provisions in the building code

Identification of potential falling hazards from ceilings, walls, balconies, parapets, fixtures and non structural elements of the towers/buildings/common areas

Documentation of existing conditions. Attach important photographs and mark the locations.

Categorize the type and severity of damage and recommend further course of action

Recommendations by Building Repair Committee

Prepare an advertisement for newspaper and invite Technical Bid from qualified Assessors/Architects/Agencies, in a sealed envelope. The Assessors/Architects/Agencies must be approved by organizations like Noida Authority or PSUs.

The Assessor/Architect/Agency must show proof of experience of similar type of assessment in the past.

Follow the tendering process of Noida Authority or PSU like CPWD etc.

Only Technical Bids should be invited in the first stage.

Open the sealed Technical Bids in presence of all members of the Building Repair Committee. Every member must sign on each Technical Bid received.

Prepare a Comparative Chart of all the technical bids and present this information in GBM for approval.

Call the selected assessors and speak to each of them in detail to clarify points in GBM, to all stake holders (flat owners). Add more action points to the Technical Bid, if required, to make it complete and foolproof.

Now ask all the selected assessors for Financial Bid. These Financial Bids should be given in a sealed envelope.

Open the Financial Bid in GBM. Select L1 and do further price negotiation to bring down the cost. No cost overrun should be allowed.

Take approval of GBM for award of Condition Assessment Contract.

Award the contract.

Building Repair Committee to monitor the assessment being carried out by the selected Assessor.

Conclusion

It is vital to carry out condition assessment in proper way. It ensures proper evaluation and safety of the towers and related structures. Safety evaluation forms the basis for carrying out repair and retrofitting/strengthening of towers and basement structures. We must follow proper procedures to satisfy the safety and performance standards as per existing building codes which are applicable to us.

All technical and financial decisions must be taken in GBM. Approval of GBM must be taken at each stage while selecting an Assessor or Architect or Agency. All bills of payment to the selected Assessor or Architect or Agency must be approved in GBM and should be posted on Notice Boards immediately on payment.