Going Underground with Sub-Surface Surveys
Before a building project is developed and actual construction begins, it is necessary that developers understand what lurks beneath a particular plot. Soils testing is one analysis that can determine whether building plans are viable. Of course there are other potential issues such as seismic shock factors and any other underground disturbances that can occur along with organic decomposition. Hazards and faults need to be investigated and archaeological information needs to be taken into consideration, too. Geo-physical testing is often needed when larger plots are being investigated.
Without this knowledge, safety, budget and quality are at risk as well as the success of a project as a whole. It goes without saying that thorough awareness of what is going on under the ground determines how well a building will be constructed above ground. Another area of investigation is known as sub-surface utility engineering (SUE), which in short locates and maps underground utilities.
Sub-surface surveys in Hong Kong are focused on looking at a multitude of potential issues during and post construction. These services evaluate and provide data and images on a variety of concrete-related issues under the ground. This includes mapping reinforcement bars which make up reinforced steel, which are known in the trade as rebars. The location of these rebars can be pinpointed, as can post-tension cables. Many of these tests are valuable as construction is carried out.
While many of Hong Kong’s buildings tower above the ground, there is a lot of activity underneath as well, within deep foundations. The safety of nearby structures needs to be ensured, as well as ground water levels detected.
Imaging can be used to detect any sub-surface obstructions and determine structural integrity of a building below ground, as well as detecting and mapping any voids and cracks. Prior to construction, the depth to bedrock also needs to be determined. It has to be noted that sub-surface surveys can relate to what is happening underground in general, while concrete radar surveys look under the surface of the concrete, for example checking out reinforced steel quality.
Sub-surface factors are important to locate and map so that they are not compromised during drilling or any other procedures such as coring. On top of this, there are safety issues to ensure that construction workers are adequately protected. It is also vital that utility lines are not inadvertently cut and that equipment is not damaged.
