Troubleshooting & Conditioning Evaluation Services
Evaluation of Existing Concrete Structures and Pavements
Forensic Studies And Dispute Resolution Support Nondestructive Evaluations
During Construction
- Troubleshooting production and construction practices
- Investigation for suspected discontinuities (delaminations and porous areas)
- Development of repair recommendations, and confirmation of the soundness of repairs
- Confirmation of concrete proportions and constituting materials for compliance with the approved mixture design
- Investigation of conditions and mechanisms contributing to defects to prevent reoccurrence
- Validation of position of steel reinforcement and load transfer devices (dowel and tie bars)
- Validation of mechanical properties, air-void system, and transport properties of concrete
Existing Structures and Pavements
- Development and confirmation of as-built documentation
- Condition assessment of reinforcing and structural steel
- Durability and service life assessment (remaining services life)
- Technical support of planned and emergency repair and rehabilitation
- Condition assessment of concrete, unit masonry, plaster, and stucco
- Evaluation of material conditions impacting functional and structural performance
- Observations and evaluations for seismic upgrade
- Condition monitoring
Forensic and Dispute Resolution Support Services
- Determination of material-related distress mechanisms affecting cementitious-based building building materials
- Determination of distress mechanism initiating conditions
- Analyses of impacts of design, construction specifications, and practices on distress/cracking
- Dispute resolution and litigation support
- Determination of material-related distress mechanisms affecting cementitious-based building materials
- Sampling of concrete and steel for laboratory testing, examination, and analyses
- Assessment of repair options
We Use The Following Techniques
Survey and Documentation
- Visual assessment of conditions
- Instrumented survey
- Mapping, photo, and video documentation
- As-built drawings
Nondestructive Evaluations
Twining Concrete Insight often turns to state of the art nondestructive evaluation (NDE) methods to supplement more traditional evaluation methods. These NDE methods allow Twining engineers to gather information related to structural conditions more quickly, less intrusively, and often more accurately than with traditional evaluation methods alone. Whether determining the extents of damage resulting from corrosion of reinforcing steel within a concrete retaining wall for a high-rise building, documenting the as-built profiles of post-tensioning tendons within a 50 year old parking deck, measuring the section loss of a structural steel girder for a dilapidated historic bridge, or countless other applications in between, Twining engineers utilize NDE methods extensively to develop a deeper understanding of structural conditions that would not be possible with traditional evaluation methods alone.
- Ground-penetrating radar (various frequency antenna)
- Ultrasound pulse velocity
- Half-cell potential
- Dye penetrant
- Surface hardness (Leeb hardness, Schmidt hammer)
- Impact echo
- Shear wave tomography
- Electrical resistivity
- Magnetic particles
General Testing, Examination, and Analyses of Samples Extracted from Structures and Pavements
- Testing concrete for mechanical properties
- Scanning electron microscopy
- Wet chemistry analyses for water-soluble and acid-soluble chlorides
- X-ray diffraction analysis
- Physical measurements of loss of cross-section
- Optical microscopy
- Energy-dispersive X-Ray analysis
- X-Ray fluorescent analysis
- Mechanical testing of steel
- Analyses for chemical composition of steel
Special Analytical Methods Used for the Assessment of Service Life
- Rapid-chloride permeability (USA and EN methods)
- Coefficient of chloride diffusion (direct analysis, and formation factor-based estimation)
- Chloride-binding isotherm
- Electrical Resistivity
- Formation factor
- Expansion of concrete due to residual reactivity of aggregates with alkali
Service Life Modeling
Corrosion of reinforcing steel is one of the most prevalent causes for the deterioration of reinforced concrete structures. With our sophisticated knowledge on concrete materials and our in-depth understanding of modeling software, Twining is well prepared to assist you with any projects where service life is of concern.
- Life 365
- FIP Model Code Bulletin 34 (USACE approved method)