The research program at the University of Southern California (USC), on the Integrated Analytical and Experimental Studies for the Evaluation of Reinforced Concrete Structures, aims at developing an integrated approach towards the seismic design of reinforced concrete structures as well as investigating the application of high strength concrete for structures located in regions of high seismicity.

Experimental Studies

1. Structural System Evaluation
   The activity aims at the evaluation of the economic effectiveness of the use of HSC through a comparative study of the seismic performance of different structural systems. Framed Tubes, Perimeter Moment Frames, Exterior Braced Tubes and Structural Walls are the main topics investigated.

2. High Strength Concrete Mix Design
   Different mix proportions and concrete recipes as defined by USC are tested to provide guidelines of producing High Strength Concrete from Southern Californian local materials. Tests on concrete cylinders on 1, 7, 28, 56 and 91 days of age are undertaken.

3. Material Tests
   Tests aim at the quantification of the mechanical properties of High Strength Concrete mixes previously developed. Split Tension, Flexural Strength, Shrinkage and creep tests are the main areas of investigation.

4. Confined Compression Tests
   Axial strain, lateral and longitudinal confined specimens are tested during summer of 1994 to provide the required information about the expected effects of confinement of HSC members. Confinement is an essential property for structures in seismic regions.

5. Interior Beam-Column Connections
   The seismic shear performance of interior beam-column joints is studied. The investigation will introduce a better understanding of the behavior of joints through calibrating an effective computer tool for joint analysis. The effect of variation of axial column load as well as the use of fiber reinforcement constitute the main topics investigated.

6. Exterior Beam-Column Connections
   For a better approach for the design and analysis of high strength exterior joints, full scale exterior beam-to-column connections are tested. The specimen configurations cover a spectrum of parameters. Wire mesh reinforcement and deep beams are the parameters considered during 1994-1995 schedule.

7. Beam Shear
   The study will help demonstrate how conservative the current design codes are in beam shear design. Reduced scale models of cantilever beams are tested to investigate the concrete contribution to shear resistance in regions of high flexural strains. The subject is vital and will cover a present gap in current design needs.

8. Epoxy Repaired RC Structures
   After the Northridge Earthquake, the need to explore repair and retrofit techniques became more urgent. Various repair Techniques for NSC and HSC will be investigated.

ANALYTICAL STUDIES

The program aims at providing a dependable analysis methodology. The analytical tool will account for most of the behavior characteristics of NSC and HSC. This will result in an accurate representation of the seismic performance of RC members and structural systems in regions of high seismicity. High strength concrete constitutive relationships are formulated based on test results and provide the necessary information for precise modeling of RC structures. Exterior joint models, 3-D joint models and wall models are also included in the study. Correlation studies with the Interior Joint, Exterior Joint and Beam Shear programs constitute a major analytical activity in support of experimentation.

TECHNOLOGY TRANSFER

The technology transfer program develops a base among young engineers that will help support code improvements. This is accomplished through improving the level of understanding of the behavior of RC structures. A graduate level course has been taught at USC for graduate students and practicing engineers. Technical publications are a major task for the USC program. Several journal and conference papers have been published over the past four years along with USC reports. Communication with technical societies is also maintained to ensure the applicability of the research topics to the daily practice needs. This material will be compiled having as a focus design practice and code requirements.

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