Structural Assessment

Our Building integrity study in UAE includes an assessment of the whole structure including the buried elements by the Building As-built Survey and Building condition survey . The assessment of concrete strength in existing structures shall be carried out according to ACI-562 and ACI-563 or BSI 6089-1981. Sophisticated investigation techniques will be utilized to study materials other than concrete. These techniques may be non-intrusive or may require the opening or removal of building fabric. Locations for inspection openings and sample removal shall be as non-intrusive as possible to the fabric. Enough material samples, structural members, and connections shall be examined to offer a representative study. Field investigation works will include but not be limited to the following:

• Excavating sufficient (if required) number of trial pits to reveal the condition of the concrete in the foundation (raft) and retaining walls, extracting concrete cores as per the following relevant standards and codes.
• Carry out field carbonation tests and obtain dust samples for laboratory chemical testing.
• Carrying out a cover meter survey at selected locations in order to determine typical reinforcing cover and an indication of rebar arrangement.
• Carrying out a delamination survey to assess any areas where loss of steel-concrete bond has occurred.
• Inspecting the general condition of concrete and reinforcing. Assessing the degree of reinforcing corrosion at selected locations by comparison with the original steel bars that are still intact. Visual survey of structural steel to determine existing characteristics (if any).
• Measuring types and geometry of cracks onsite by crack width opening test. Collecting samples from the cement blocks or lime bricks of walls. Visual testing of the timber, joinery, and finishes of wood for boring insects and decays.
• Carrying out both boreholes and SPT tests to check the bearing capacity and water level under the structure as required. Recording the nature of the structures and locating possible movement types if any. Checking member conditions for further evaluations.
• Condition of the construction material in wall members and mechanical fixation. Recording evidence of deterioration and visible signs of distress. Checking electro-potential corrosion conditions.
• Discharge the water from the lower basement. Identify and monitor the locations of water leakage through the foundation and retaining walls.

Carbonation Depth Measurement: The phenolphthalein test method is intended to measure the depth of the carbonated layer near the surface of hardened concrete. It is not suitable for concrete made with calcium aluminate cement. It may be used on site or in the laboratory, on test specimens or on cores or fragments removed from hardened concrete structures. The pH of cement paste is roughly 13, which gives the steel reinforcement a passive coating that shields it from corrosion. Around pH 11, passivity starts to decline. The pH is lowered because of the concrete becoming carbonated due to atmospheric carbon dioxide. A phenolphthalein indicator solution, which turns pink when in contact with alkaline concrete that has a pH higher than 9 and colorless at lower pH levels, is used to measure the depth of carbonation. The most popular method for performing the test is to spray the indicator onto recently exposed concrete surfaces that have been broken from the building or onto split cores.

Half-Cell potential: Half-Cell Potential (HCP) measurement services using an electrochemical technique can be used to evaluate steel corrosion, in accordance with ASTM C87. The electrical potential difference between the top steel rebars and a common portable reference electrode that is in contact with the concrete surface is measured using this technique. Other combinations may also be employed, but the half-cell is made up of either a copper/copper sulphate or silver/silver chloride cell. As an electrolyte, the concrete may be empirically connected to the measured potential difference to mitigate the risk of corrosion of the steel reinforcement in the immediate vicinity of the test site. The reliability of half-cell potential measurement as an indication of corrosion potential has evolved by the good results during the bridge deck corrosion surveys.

To accurately evaluate the corrosion damage of a reinforced concrete structure using a half-cell potential survey, thorough preparation, measurement, and data correlation are necessary. Before interpreting the corrosion probability, the half-cell potential data should always be verified using additional testing techniques. The half-cell potential methodology is frequently used in conjunction with a variety of other techniques for field corrosion assessment, such as visual inspection, delamination surveying, measuring chloride content, measuring concrete resistance, conducting a concrete cover-depth survey, determining carbonation profiles, etc.