Ma et al. 2006
This research focuses on the ability to predict dynamic rocking response of PT concrete systems when subjected to earthquake excitations. Three frequently used analytical modeling techniques were compared to shake table test results. Challenges and analysis deficiencies are discussed.
System Concept
Concrete masonry walls which are allowed to rock about their base are examined. The rocking force due to ground excitation is countered by vertical PT strands. When compared to conventional walls, the system has the ability to soften laterally and rock non-destructively under large seismic events. The PT strands are designed to withstand DBE and still be economically repairable.
Experimental Study, Results, and Discussion
The three frequently used analysis procedures are as follows: Conducting the entire analysis through robust FEM programing, idealizing the wall as a lumped mass system and implementing fiber elements consisting of a series of compression-only springs to model the wall base, or idealizing the wall as a single degree of freedom system, implementing a nonlinearly elastic rotational base connection.
Previous experimental data collected from experimental testing on a PCM wall was compared to the three analysis procedures. The PCM wall was subjected to a scaled 94’ Northridge earthquake record through a shake table.
It was found that of the three analysis methods, not one was able to significantly match experimental data in terms of synchronicity and peak displacement. It is concluded that the dynamic behavior of controlled rocking walls is complicated and is not yet accurately modeled based on this procedures. More research is needed in the future.
Reference
Ma, Q. T., Wight, G. D., Butterworth, J. W., & Ingham, J. M. (2006). "Assessment of Current Procedures for Predicting the In-Plane Behaviour of Controlled Rocking Walls." In Proc. 8th US National Conference on Earthquake Engineering.