August 26, 2014
Much of the working development length of the anchorage is hidden from view due to embedment into building construction materials, such as brick, stone, mortar, wood, and concrete. In industrial facilities, anchorage of process stream lines, vessels, and rotating/reciprocating equipment onto supporting foundations is handled by threaded metal rods embedded into conventionally reinforced concrete. Unfortunately, the condition of the ‘business end’ of the anchor bolt is unknown until an owner/operator experiences an unfortunate event in the form of: Bolt tensile failure Pullout (concrete...
August 26, 2014
Once concerns are raised, the implementation of a proactive evaluation program should be initiated that treats the anchor bolts as critical components of an important asset. Several types of evaluation programs can be assembled which are generally a mix of non-destructive (NDT) and semi-destructive (SDT) techniques that work concurrently to quickly assess the type, quality, and quantity of the tested anchor bolts. Essentially the testing techniques available include: Acoustic impact Each anchor bolt is struck with a 3 lb. maul hammer and the audible resultant tonal variations are noted. For...
August 26, 2014
Several strategies are available to reestablish anchor bolt integrity. Anchor bolts restoration strategies can be as follows: Repair existing anchor bolts Near surface separated anchor bolts can be repaired using mechanical couplings or welding stud extensions. Both techniques remove and replace anchor bolt threaded regions damaged by corrosion, lateral shear, or vertical ‘cup and cone’ failures. Property installed and incorporating appropriate metallurgical detailing, repairs as described can add significant service life to the existing anchor bolt system, once the ‘root cause’ of the...