|Session 7.2 - Structural Materials|
The Engineering Directorate of the National Science Foundation (NSF) of the United States has initiated a major program designed to advance earthquake engineering by infusing it with recent developments in information technology (IT). The program is the George E. Brown, Jr. Network for Earthquake Engineering Simulation (NEES). The components of NEES are currently under development and are scheduled for completion in the fall of 2004, to be ready for NEES Collaboratory research. "Collaboratory" is a term derived from "collaborative" and "laboratory" that describes how researchers, whether they are conducting experimental or simulation investigations, can use information technology tools to work at the same time on the same research project even though they are not located in the same physical laboratory. NEES is planned to be operational from 2004 through 2014. Further information on NEES is available at http://www.nees.org./.
Paper 057: [Read]
L.M. Megget, R.C. Fenwick and N. Amso
To assess the performance of grade 500 reinforcement in beam-column joint zones, three beam-column sub-assemblies were built and tested. The units were detailed to comply with the minimum requirements of the Structural Concrete Standard in the joint zone. The test results show that bar slip occurred at ductility levels appreciably lower than the permissible design values implied in the Loadings and Structural Concrete Standards. This slip led to a loss of stiffness together with a loss of strength. It was also found that replacing grade 300 reinforcement with grade 500 reinforcement significantly reduces the effective stiffness of both the joint zone and the beams in the pre-yield load cycles. To avoid the problems associated with both bond in internal joint zones and loss of stiffness in beams, it is recommended that the beams of ductile moment resisting frames should be designed using grade 300 reinforcement.
Paper 100: [Read]
Keywords: joints, bond, stiffness, slip
A. Bai, J.M. Ingham and R. Hunt
International literature reporting on reinforcing mechanical connection system testing protocols and experimental studies conducted in the United States, Japan, and Europe were assessed to provide recommendations for an upcoming review of the New Zealand reinforced concrete design standard. Both static and seismic conditions, in terms of their relevance in the New Zealand context, were considered in the literature review. At conclusion of this exercise, new standard criteria for the use of mechanical connection systems in New Zealand were proposed, and a range of couplers commonly used in New Zealand were subjected to preliminary tests in accordance with the proposed standard criteria. Testing indicated that the couplers performed in a satisfactory manners.
Keywords: Mechanical Connectors, Splices, Reidbar
Grade 500 Reinforcement: Design Issues with L, N and E Grade Reinforcing Steel and the Overstrength of Pacific Steel Micro Alloy Reinforcement
Using the principles of capacity design, it is necessary to be able to predict the maximum strength of the yielding elements in a structure. The ratio of the maximum moment capacity divided by the nominal moment capacity is commonly called the overstrength factor for a reinforced concrete member. With the introduction of Grade 500 reinforcement into the marketplace, it is necessary to determine the change in the overstrength factor compared to that for Grade 430 reinforcement. This paper presents the results obtained from an analytical study aimed at determining the overstrength factor for concrete members with Grade 500 reinforcement as longitudinal steel.
Keywords: Grade 500 reinforcement, overstrength