Showing papers by "Mohamed A. ElGawady published in 2012"

Behavior of Segmental Precast Posttensioned Bridge Piers under Lateral Loads

Abstract: A segmental precast posttensioned (SPPT) bridge pier is an economic recentering structural system. Understanding the seismic behavior of a SPPT system is an important step toward its application in high seismic zones. This paper presents a detailed three-dimensional finite-element (FE) model that was developed using the ABAQUS platform. A brief description and discussion of cyclic tests on eight large-scale SPPT piers is also presented. Four of the piers were constructed and tested to a predefined degree of damage. Then, these piers were retrofitted and retested. The FE models developed and presented in this paper predicted the backbone curves of the piers that were tested directly after construction with an average error of 7% for drift angles smaller than 2.5%. For drift angles greater than 2.5%, the average error reached 13%. For piers that were retrofitted and retested, the error in predicting the backbone curve depended on the state of damage before the retest. When preexistent microcracks we...

Static Cyclic Response of Partially Grouted Masonry Shear Walls

Abstract: This research investigated the shear behavior of five full-scale partially grouted masonry shear walls (PG-MWs). The walls were built using concrete masonry units, with horizontal reinforcement ratios ranging from 0.085 to 0.169%. The specimens had horizontal spacing between vertical grouted cells ranging from 610 (24 in.) to 1,219 mm (48 in.). All the specimens were tested under constant gravity load and incrementally increasing in-plane loading cycles. This research showed that there appears to be a maximum horizontal reinforcement ratio after which no additional shear capacity is achieved. As indicated by the experimental results, the maximum value appears to be approximately 0.1% for specimens with horizontal spacing between vertical grouted cells of 1,219 mm (48 in.). Increasing the horizontal reinforcement beyond this level did not increase the shear strength of the test specimens. In addition, the current provisions of the Masonry Standards Joint Committee (MSJC), the New Zealand code for m...

Comparisons between shear strength predictions of partially grouted masonry walls in Australian and international standards

Abstract: The objective of this paper is to compare the in-plane shear strength of partially grouted masonry walls (PG-MW) in the Australian code (AS3700-2001) with other codes. This is of high importance because while most of the test experiments have been done recently - and have affected other codes, shear equations in the Australian masonry design code remained relatively unchanged since 1988 (AS3700-1988). Therefore it is important to find out the differences between Australian provisions and provisions in other codes such as MSJC-2011, NZS4230-2004 and S304.1-2004. These codes were selected as they were calibrated against comprehensive test results. In this paper the effectiveness of various parameters that influence the shear strength of PG-MWs is investigated and discussed. The differences between the selected design provisions are also highlighted. The comparison shows significant differences between AS3700-2001 and the other codes' design expressions.