As a company defined by our expert services, we ensure that our client’s requests are matched with both dedication and effectiveness.
Recently, our team at J&B Coring was requested to do exploratory and analytical work to determine the existing structure of this building. Unfortunately, the drawings and building plans are currently missing and so for the purpose of making informed decisions when it comes to making design changes, we employ a comprehensive survey of the structure.
The exploratory and analytical work done varied from a rebar survey to exposing and identifying foundations and ground beams. When looking to renovate without the right information, we utilise the following strategies.
The Rebar Survey:
First off, we start with a rebar survey in order to identify the structure in columns and beams. The Ferro scanner was thus used as it effectively identifies reinforcement diameter, cover and spacing.
As such, the scans allow the structure to be identified and drawings of the structure or main structures to be properly completed. Average covers and spacing can be determined by main bars, stirrups, and other reinforcement in various structures.
Images: Column indicating main bar positions and the measured diameters.
Images: Beam indicating main bar positions and the measured diameters.
Core Samples:
The next step is to conduct core sampling so that we can determine the compressive strength of the concrete. The concrete MPa is determined from the concrete testing done on individual core cutting samples. The scans allow for safe core sample positions to be identified so as to not damage the structure from which the core samples are taken.
Ground beam and foundations from core holes:
Small cores are drilled through the surface bed and further exploration below the sand is done to identify if there is concrete below the soil. A depth of 1.2 metres was checked and multiple positions found concrete around and between the columns.
This process allows a simple understanding of the structure around and between the columns. As seen in the graphic below, clear indications of ground beams and the absence of foundations can be determined.
Image: Red = concrete found and blue = soil up to 1.2m
Exposure of foundations:
The foundations needed to be exposed and measured. The best method to do this in the basements was to cut a portion of the surface bed out and expose the foundation and ground beam below the perimeter walls.
This allows the engineers to measure the size and estimated strength of the foundations to determine the capabilities of the foundations for any further design changes to additions.
Image: Exposed ground beam and a portion of the foundation under the column.
Contact J&B Coring for professional and reliable construction coring
J&B Coring has completed projects for multiple corporate and government initiatives from the Gautrain to modern and sophisticated business parks in and around the Johannesburg area.
We offer a complete coring service solution to all your concrete demolition and cutting needs.
Contact us today for a comprehensive quote on our diverse service offering.
Tel: +27 (0)10 100 8793
Email: info@concretecore.co.za