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The Through beam connection detail has been identified as an ideal rigid connection for attaching steel beams to concrete filled tube (CFT) columns. A combination of analytical and experimental studies is being conducted to comprehend the behavior of this detail. The test specimen consisted of a CFT column and a steel beam passed through the column to represent an interior joint in a building. This paper presents a summary of the finite element analysis that was conducted to comprehend the force transfer mechanism and identify locations of potential stress concentration. The analytical results were verified by comparison with the experimental results. Both the experimental and analytical results showed the capability of the connection to develop the full plastic bending strength of the connected beam. The elements that contribute to the connection strength were identified as: the beam web, the steel tube, and the concrete core.

were used to upgrade reinforced concrete beams, slabs and piles. GFRP shells were also used for pile upgrade. Some of these components were reinforced and prestressed with CFRP rods and tendons. Finally, other composites, such as epoxy coatings for rebars and engineered wood were addressed. Long term Since 1992, the U.S. Navy, Naval Facilities Engineering Service Since 1992, the U.S. Navy, Naval Facilities Engineering Service Center (NFESC), has been involved in the study and use of advanced fiber Center (NFESC), has been involved in the study and use of advanced fiber reinforced plastic (FRP) composites for its waterfront infrastructure applications. reinforced plastic (FRP) composites for its waterfront infrastructure applications. Carbon FRP (CFRP) and glass (GFRP) composites were assessed and Carbon FRP (CFRP) and glass (GFRP) composites were assessed and demonstrated at NFESC and at various sites throughout the Navy. CFRP sheets demonstrated at NFESC and at various sites throughout the Navy. CFRP sheets were used to upgrade reinforced concrete beams, slabs and piles. GFRP shells were also used for pile upgrade. Some of these components were reinforced and prestressed with CFRP rods and tendons. Finally, other composites, such as epoxy coatings for rebars and engineered wood were addressed. Long term durability issues are still being investigated. This paper represents an overview of the assessment and use of FRP materials in Navy reinforced concrete waterfront structures. durability issues are still being investigated. This paper represents an overview of the assessment and use of FRP materials in Navy reinforced concrete waterfront structures.

Using experimental data from previous tests and detailed analytical studies, the applicability of ACI and AISC standard techniques for concrete-filled tubular columns (CFTs) is evaluated. The test specimens include short and slender CFTs made with normal and high strength steel tubes filled with normal and high strength concrete. The focus of this paper is on rectangular and square tubes. To gauge the success of the code-based methods, the capacities are also computed by the fiber analysis techniques, along with a member level iteration algorithm for analyzing members with significant length. The results indicate that the ACI and AISC methods can yield substantially different capacities. In general, the capacities from the ACI method are reasonably close to those obtained from detailed analytical methods so long as normal strength tubes are used. Both the ACI moment magnifier method and AISC method are appropriate for slender CFTs although the ACI method tends to match the analytically calculated capacities more closely. Neither the ACI nor AISC method is applicable for CFTs made with high strength steel tubes as both techniques substantially underestimate the capacity of such columns. For CFTs with high strength steel tubes, it is more appropriate to assume that the steel tube fully yields when the capacity is developed. A revised version of the ACI standard method was developed by incorporating this assumption. The revised ACI method provides a fairly close estimate of the experimentally obtained capacities and those from detailed analysis.

A series of push-out tests of rectangular concrete-filled tubular columns (CFT) was recently conducted. The objective of this research program was to identify the shear transfer mechanisms between the infilled concrete and the steel tube and to determine a method for evaluating the capacity of the steel-concrete interface in a CFT column. The experimental variables investigated were the wall slenderness ratio (b/t) of the steel tube and the use of shear tab connections to apply axial load to the steel tube. The results of this study indicated that three mechanisms are responsible for shear transfer along the steel-concrete interface in a push-out specimen: adhesion of the concrete to the steel surface, friction, and wedging of the concrete core. The role of each mechanism in transferring shear between the concrete and steel in the CFT push-out specimen at various stages of load and slip is discussed. Design guidelines for shear transfer in rectangular CFT columns are presented, including a proposed bond strength equation and a recommended strength reduction factor for bond.

The building standard law of Japan was largely revised in June 1998. With the revision, the adoption of the capacity spectrum method (CSM) for the seismic design procedure is being considered toward the enforcement in June 2000. In the CSM, the estimation of the demand spectrum is one of important issues, because the damping properties of a building should be appropriately considered. The equivalent damping factor of composite RCS buildings consisting of steel beams and reinforced concrete columns is investigated in this paper. The relations between the equivalent damping factor and story drift of RCS joints and frames, which have different joint detail and failure mode, are examined using the existing test results including those obtained in the US-Japan cooperative research program on composite and hybrid structures. It is indicated that the influence of the hysteretic damping of beam-column joints can not be ignored for estimating the equivalent damping factor of composite RCS buildings particularly when the strength and stiffness of joints are relatively small.