February 8nd, 2012
Metro NY ICRI Meeting

"Mechanical Anchor Strength in Historic Masonry Materials."

 The current lack of codes, guidelines or recommendations for pull-out and shear values of mechanical anchors in historic masonry materials leaves the design community to improvise the design and specification of these anchors. Guidelines available are most relevant to concrete and brick masonry. Although field-testing is employed for some projects, more commonly an arbitrary reduction of the ultimate yield values is used when designing these elements for use in natural stone. The creation of a standard or empirical design equation for these values is arduous because, unlike concrete and concrete masonry units, historic building stone units are not manufactured in a controlled environment, and their physical properties such as density and compressive strength vary from quarry to quarry and within quarry strata.

A testing program to evaluate two types of mechanical fasteners in both limestone and sandstone for pull-out and shear will be described in this course. The ultimate yield strength is correlated to both compressive strength and surface hardness of the sample stone. Stone quality was evaluated in situ using ultrasonic pulse velocity measurements. Pulse velocity is sensitive to stone density, stiffness, and flaws that may have a corresponding effect on anchor capacity. Development of a relationship between anchor capacity and stone characteristics, as measured using the ultrasonic pulse velocity approach, would permit classification of field-installed anchors requiring destructive pullout tests.
  

Speaker Bio

Kelly Streeter, P.E. - Structural Engineer
Kelly received her Bachelors in Science degree in Structural Engineering from Cornell University in 1997 where she began her association with Vertical Access. She received her Masters of Science in Structural Engineering with a concentration on nondestructive evaluation from the University of Colorado in 2002. Prior to graduate school, Kelly was employed as a structural engineer at Robert Silman Associates, P.C. where she worked on several historic structures including Frank Lloyd Wright's Taliesin and the Yonkers Trolley Barn. Additionally, Kelly has completed the RESTORE preservation program in New York