Historic & masonry Structures
Global EXperts in Historic Structures and Preservation
Public and private organizations around the globe rely on Atkinson-Noland & Associates when historic structures need assessment, strengthening or repair. Our engineers have evaluated 17th century buildings in Sierra Leone, a 19th century mission in New Mexico, the Brooklyn Bridge and even Mata Ngarau on Easter Island. We provide a full range of testing and analysis, with special expertise in nondestructive evaluation and in situ testing.
Our conservative, phased approach to projects spares client budgets, while preserving the structural integrity of historic masonry. Drawing upon four decades in research and education, our experts recommend a battery of tests to obtain materials and structural data. Naturally, we start with the least invasive tests and increase the sophistication, as required.
With data in hand, we use advanced computer models to provide accurate structural analysis. Extensive knowledge of building materials and construction methods allows us to recommend creative solutions that protect historic structures, using their inherent strength to meet client objectives.
Compatible injection fill (CIF) is customized to the material properties of the host structure, based on nondestructive evaluation and materials characteristics testing. Technicians pump a fluid, cement-based grout mixture into cracks, voids, or cavities within masonry. Low injection pressures prevent damage, while strengthening already fragile materials.
A visual condition survey locates and identifies areas of damage and deterioration. Dilapidation, cracks, signs of movement, and other localized failures are mapped and documented on drawings to help determine scope of required repair work. Significant structural cracks are measured for size, location and directionality, where accessible. In addition, sources of deterioration and likely causes of damage are identified, along with repair recommendations, as applicable.
This advanced computational analysis technique aids in evaluation of structural behavior, based on accurate numerical simulation of the structural response under load. By adopting reasonable modeling strategies and material properties of the actual structure (as determined through nondestructive investigation and evaluation), finite element (FE) modeling enhances the diagnosis and understanding of damage and visual distress. FE modeling also allows for an in-depth safety evaluation of the structure, contributing to the design and validation of proposed interventions.
A flatjack is a flexible steel envelope, thin enough to fit within a masonry mortar joint. During testing, the flatjack is hydraulically pressurized and applies stress to the surrounding masonry. Flatjack tests can determine engineering properties of older and historic structures for structural evaluation, including in situ stress (ASTM C1196), masonry compressive modulus (ASTM C1197), masonry compressive strength (ASTM C1197), and mortar shear strength (ASTM C1531).
Infrared thermography uses a hand-held camera to detect differences in temperature as little as 0.1° F. This technique allows identification of structural features and conditions not otherwise detectable by visible light. Applications include rapid location of grouted cells within concrete block, moisture infiltration, cracks in masonry, and variations in insulation. Unlike other techniques, infrared thermography allows the quick, efficient survey of large areas.
Nondestructive tools such as moisture meters, surface-penetrating radar, and infrared thermography can identify areas of high moisture content and track moisture penetration back to its source. Spray tests are often used to identify moisture leakage pathways and the rate of moisture infiltration. ANA can perform tests in accordance with ASTM C1601, ASTM C1715, ASTM E514, ASTM E1105 and AAMA 501.2.
This form of structural analysis assesses a structure’s resistance to earthquake loads. Seismic retrofit solutions are designed to be compatible with the existing materials. In working with historic structures, ANA uses internal strengthening techniques whenever possible to avoid altering the building’s outward appearance.
Structural analysis characterizes the structural response when subjected to a variety of conditions and actions, such as changing environmental conditions, new load requirements, etc. This assessment involves evaluating a structure under stress, deformation and displacements, and reactions. Nonlinear analysis through finite element (FE) modeling can be used to pinpoint the source of excessive stress leading to damage of the structure (e.g., cracking in tension, crushing in compression) when evaluated under service and ultimate load ranges.
ANA can recommend appropriate repair techniques for a variety of structures, from modern commercial and industrial structures to protected historical monuments. Structural repair services extend from initial assessment to development of rehabilitation schemes, on-site observation, and quality control of repair measures.
Surface-penetrating radar (SPR), also referred to as ground-penetrating radar or impulse radar, provides valuable information about structural and non-structural building components without causing damage. The radar data reveals voids, construction layers, and the presence of other materials, such as metal inclusions, as well as the thickness of the element.