sriram aaleti

ABSTRACT Following the satisfactory response of the unbonded post-tensioned precast concrete jointed wall system tested for seismic performance as part of the PREcast Seismic Structural Systems (PRESSS) test building, a set of design guidelines was published. Based on these guidelines, Thomas & Sritharan (2003) developed a procedure to analyze the unbonded jointed wall systems. The primary objective of this research is to improve this analysis procedure so that it can be applied to analyze both unbonded post-tensioned single walls and jointed wall systems. Using the experimental data from PRESSS test building, ATLSS research center single wall tests, the accuracy of this analysis procedure and that based on the monolithic beam analogy (MBA) are examined. It was found that both the analysis methods predicted the moment resistance of the walls adequately at the given base rotation. Based on these analysis procedures, revised set of design guidelines are proposed for design of precast jointed wall systems with unbonded post-tensioning steel. A detailed investigation on the influence of several wall parameters on the lateral load behavior of jointed wall system is conducted and a new jointed wall concept refer to as the "jointed wall-column (JWC) system" is proposed. It is shown by analysis that, the JWC system will be more economical than that of an equivalent jointed wall system tested in the PRESSS building. Typescript (photocopy) Thesis (M.S.)--Iowa State University, 2005. Includes bibliography.

This report studies the viscoelastic behavior of elastomeric bearings with the effects of axial load taken into consideration. First, two series solutions are presented for computing the compression stiffness of bonded square layers accounting for compressibility. For typical square rubber layers, these solutions justify a simplified approach. The latter is then extended to obtain the effective bending stiffness. Then, with this effective stiffness of elastomeric bearings, two viscoelastic P-delta models are proposed. The first model is ...