Structure Audit

Structure Audit is the survey of building to reveal its worth in terms of strength and stability. Prism’s team of skilled evaluators perform tasks as visual inspection and various tests to arm our clients with the right knowledge, exact strength and life of structure. We suggest retrofication wherever required.

Structural audit of existing structures to know exact strength and life of Structure. We suggest retrofication wherever required.

Some Methods to do Structural Audit

• This is one of the most commonly used methods, in which theultrasonic pulses are transmitted through theconcrete.
• This test is conducted by passing a pulse of ultrasonic through concrete to be tested and measuring the time taken by pulse to get through the structure. Higher velocities indicate good quality and continuity of the material, while slower velocities may indicate concrete with many cracks or voids.

• Moisture is known to be one of the main sources causing deteriorationof masonry and timber structures.
• To identify leakages and dampness moisture meters are veryhelpful.
• If the concrete, masonry, timber structures are found to be wet, then appropriate repairs can be carried out to avoid further decay deterioration of the material and structure as awhole.

• The simplest way to assess the severity of steel corrosion is to measure the corrosion potential, since it is qualitatively associated with the steel corrosion rate. One can measure the potential difference between a standard portable half-cell, normally a copper/ copper sulphate (Cu/CuSO4) standard reference electrode placed on the surface of the concrete with the steel reinforcement to the negative. This test can give the probability of corrosion activity taking place at the point where the measurement of potentials is taken from a half-cell, typically a copper-copper sulphate half-cell. An electrical contact is established with the exposed steel & half-cell is moved across the surface of concrete for measuring the potentials.

Endoscopy surveys provide a fast, cost effective means of identifying problematic/ in-accessible areas where bear minimum destruction is allowed for inspection such as –
• ConcretePipes
• Water Pipes
• StormPipes
• Sewerpipes
• Culvert
• CavityWalls
• Air Ducts, Vents
• Ceiling, roof and floorvoids
• Water tanks
• Concrete or Masonry structures with large voids, honeycombingetc.

• Dams
• Bridges
• Water Tanks
• Effluent & Water Treatment Plants
• Jetty
• Underwater Structures corrosion capturedby
• UnderwaterCamera
• Inspection of Jetty and Bridge Foundations by UnderwaterCamera.

• This is the most common method for the checking strength of concretesince 1940.
• The test is based on the principle that the rebound of an elastic mass dependson the hardness of the surface against which massstrikes.
• The plunger of hammer is pressed strongly and steadily against the concrete surface at right angles to its surface, until the spring loaded mass is triggered from the lockedposition.
• The distance traveled by the mass as a percentage is defined as reboundnumber.
• This test does not give accurate results.

• This is one of the very reliable tests adopted for checking the compressible strength of the“In situconcrete”
• Other Physical properties such as density, water absorption can alsobe measured from the coreconcrete.
• In addition chemical properties of concrete specimen for its cementcontent, carbonation depth, chloride and sulphate content may bemeasured.

• The reinforcement bar is detected by magnetizing it and inducing acirculating “eddy current” init.
• After the end of the pulse, the eddy current dies away, creating aweaker magnetic field as an echo of the initialpulse.
• The strength of the induced field is measured by a search head as it diesaway and this signal is processed to give the depthmeasurement.
• The eddy current echo is determined by the depth of the bar, the size of bar and the orientation of thebar.
• This detection of location of reinforcement is required as a preprocess for core cutting.

• It has been established that cast in situ piles in majority of the cases fail because of defective pile shaft necking, discontinuity of concrete, intrusion of foreign matter and improper toe formation due to contamination of concrete at basewith soilparticles.
• Washing of concrete due to high water current, adoption ofimproper construction method, poor quality control on concretingetc.
• Cracks developed while handling of precast piles can also be a cause offailure.
• Ifpileintegritycanbeassessedbeforecompletionofpilecaps,thenthiswillgoa long way towards certification of pileintegrity.

• Structural vibration in buildings can be detected by the occupants and canaffect them in manyways.
• Their quality of life can be reduced as also can their workingefficiency.
• Ground borne vibration from sources such as blasting, piling, machinery or road/ rail traffic can be a source of concern for occupants of buildings in the vicinity.
• The concern can lead to a need to assess the effect of the imposed vibrationon the building structure to ascertain whether damage couldoccur.
• It is increasingly recognized that buildings must sustain vibrations, and recognition of this is needed both in design for structural integrity,serviceability and environmental acceptability and in the preservation of historicbuildings.
• Measurement of vibration in a building is carried out for a variety of purposes.

• Using the ultrasonic thickness gauge we can find out the precise thickness of all such steel metal structures, components.
• Ultrasonic Thickness gauge a very useful tool in the structural audit/survey.
• In most of the industries, especially in chemical factories, corrosion is a very serious issue for the structural stability of the steel structures, MS Chimney, Stacks, Gantry, girders, Pipe racks, Pipelines etc.
• Using the ultrasonic thickness gauge we can find out the precise thickness ofall such steel metal structures, components.

• Used in combination with Moisture meters to identify the temperature gradient and spot temperatures from a long distane by just sighting the object.
• A very useful tool in structural audits of the buildings, waterstructure, Chimneysetc.

The state of Art Technology Used for
• 3D imaging ( Tomography ) of shallow and deep rebars in concrete
• Inspection of concrete for location of voids, internal defects, delaminations and cracks
• Inspection of concrete thickness, integrity
• 3D imaging of pre-tension and post-tension cables
• Inspection and analysis of old structures and monuments
• Inspection of walls and floors for the location of pipes, objects, caches, etc
• Locating Utilities

FWD is used to do audit of Roads, Highways, Airfield pavements. FWD is used for evaluation of load carrying ability of airfield pavements and highways. It is a device which is equipped with a standard 300 mm diameter segmented plate and coated with rubber pad to help in disseminating the load uniformly.
Test method permits a force amplitude and duration resembling the effect of a heavy moving wheel load and very precise deflection measurements, especially at large distances from the center of the load. The productivity of the FWD regarding pavement surface deflections for an applied load.

Features of the Falling Weight Deflectometer testing tool
The Falling Weight Deflectometer put in a dynamic load that simulates the loading of a moving wheel. The pavement reply is analyzed with software to control the elastic moduli, strains of each modeled layer. It announces the weakest layer of failure, residual life and determines the best rehabilitation choices.

Key Advantages of the Falling Weight Deflectometer
• Automatic and fast structural pavement testing relevant to pavements all over the world
• Regulates the layer of failure, rather than determining the bearing capacity
• QA/QC of afresh built pavements
• Equates a variety of rehabilitation choices, including plane off and recycling rather than applying overlaps.
• The use of the FWD offers correct, reproducible and repeatable structural information.
• Automated and real-time intensive care of the load cell, geophones, and data differences safeguards high quality of composed statistics.
• Practices mechanistic-empirical analysis applicable to most of pavement structures