This Press Release has been prepared by the Management of BICON Zambia Limited in order to provide the General Public and all the Stakeholders with the relevant background and information with respect to the ongoing Column Strengthening Works at the Office Block at the Society Business Park following the various statements and reports that have appeared in both the print and electronic Media with respect to this subject.
The contract for the Re-Development of Society House and Central Arcades was executed in 2011 between the National Pension Scheme Authority (NAPSA) and Yangts Jiang Enterprises Limited (YJL) who in turn engaged a Team of Consultants in order to deliver the project as a “Design and Build” Turnkey Project. YJL was responsible for the construction of the works whilst the Consultants were responsible for the Design and Supervision of the Works. BICON Zambia Limited was responsible for the Design and Supervision of the Structural Engineering Works.
The scope of the project involved the conversion of the then existing 18-storey office block which was formerly occupied by the Zambia National Building Society into a 148-room hotel as well as the demolition of Central Arcades and the construction of a Retail Mall, Parkade and an Office Block on top of the parkade.
QUALITY CONTROL MEASURES DURING CONSTRUCTION
As part of the various quality control measures adopted during the implementation of the project, YJL engaged the University of Zambia (UNZA) and Wade Adams as an independent laboratory responsible for the testing of the concrete works on the project. All the results made available by YJL from Wade Adams to the Structural Engineers during the implementation of the project were found to be satisfactory.
FAILURE OF COLUMN T5 ON THE 1ST FLOOR OF THE OFFICE BLOCK AND SUBSEQUENT INTERVENTIONS
The entire Society Business Park Project was completed on a sectional basis starting with the Retail Mall and Parkade in 2016, followed by the Office Block in 2017 and then the Hilton Garden Inn in 2018. It must be noted that the 18-storey hotel block structure is totally independent from the rest of the development which was constructed in the 1978.
On the 13th of October 2019, one column on the 1st floor failed by way of crushing at the intersection of the column and slab which also and as a result of the failure stressed the three neighbouring columns on the 1st floor level. As a precautionary measure, the Owners of the Building NAPSA ordered an evacuation of the Tenants of the office block in order to facilitate a detailed examination of the office block structure.
In-Situ tests on the failed columns found that the actual concrete strength of the columns were lower than the specified concrete strength on the Structural Engineering Drawings. A detailed examination of the rest of the columns at Society Business Park Office Block found that the other columns were not showing any signs of stress following the failure of the column at the 1st floor. The columns affected at 1st floor were thereafter strengthened by casing them in steel columns in order to significantly enhance their load bearing capacity.
The repairs to the failed and stressed columns on the 1st floor were inspected by all the stakeholders including the Independent Engineer, the Engineering Institution of Zambia (EIZ), the Association of Consulting Engineers (ACEZ), the National Council for Construction (NCC), NAPSA as well as all the relevant stakeholders including the print and electronic Media.
NAPSA subsequently engaged the services of an Independent Consultant to undertake a detailed investigation in order to determine the structural integrity of the entire office block and the supporting parkade structure below.
The summary of the Independent Engineers findings are as follows:-
1. The slabs for the parkade and the office block were found to have adequate capacity to carry the design load,
2. Although not showing any signs of stress, 153 columns in the parkade and office block out of a total of 258 columns which carry the parkade and office block had column capacities lower than the design capacity due to lower concrete strengths than the specified concrete strength. This entailed that all these columns have been earmarked to be strengthened in order to increase the load bearing capacity and factor of safety of the columns.
In view of the foregoing, BICON Zambia as the Design Structural Engineers were required to submit a proposal for the strengthening of the columns identified by the Independent Engineer.
BICON Zambia thereafter engaged the services of a Specialist Concrete Company from South Africa called Mapei in order to design a concrete strengthening solution based on the required column loads. Mapei South Africa design a column strengthening solution using the Mapei Product which is manufactured in Italy to strengthen existing concrete structures and is used extensively in Africa and all over the World.
The Independent Engineer requested that Mapei submit calculations for the column strengthening works for their review. In addition to the foregoing, the Independent Engineer also requested that a sample column be strengthened on site using the Mapei Product and that the Mapei Materials be tested by an Independent Laboratory in Zambia in order to confirm that the strength of the materials which were assumed in the Mapei calculations can actually be achieved.
Subsequently a sample column was constructed on site and inspected by all the Stakeholders including the Independent Engineer, EIZ, ACEZ, NCC, including the print and electronic Media. EIZ, ACEZ and NCC were encouraged to conduct their own regular inspections of the column strengthening works in order to kept up todate with progress.
The Independent and certified Laboratory at Rankin Engineering Consulting Engineers has todate been used to test all the Mapei Materials. The Independent Engineer granted approval for all the columns strengthening works to be used on the columns which were identified for strengthening using the Mapei Product.
Following the approval of the methodology for the column strengthening works, 80% of the columns to be strengthened have since been completed. Site Progress Meetings which are attended by the Independent Engineer, BICON Zambia, NAPSA and the Contractor to review the progress of the column strengthening works as well as the Test Results of the Mapei Materials are held monthly.
In conclusion, EIZ has on three occasions with other stakeholders visited the site and have been kept informed of the column strengthening works. In addition to the foregoing, BICON Zambia has on several occasions shared with EIZ and NCC copies of the reports in connection with the column strengthening works. BICON Zambia has also attended a hearing called for by EIZ in connection with this project.
The Contractor who has taken over from YJL who is currently executing the column strengthening works under the full-time supervision of BICON Zambia is working diligently in order to complete the column strengthening works on site as soon as possible. The Independent Engineer contracted by NAPSA is also providing regular oversight and closely monitoring the ongoing works on site. Based on the current programme, the column strengthening works are expected to be completed in December 2020.
EIZ as the Regulator of the engineering industry has unfettered access to the site to inspect the ongoing works and to request from us any information, they may wish to obtain with respect to the ongoing works to enable them issue informed statements to the public with respect to this project.
BICON Zambia Limited