H. 5. Lew Chief, Structural Division United States Department of Commerce National 'Institute of Standards and Technology Gaithersburg, Maryland An experimental study of the behavior of precast concrete beam-to-column connections subjected to cyclic inelastic loading conducted at the National Institute of Standards and Technology is presented. The study was initiated to provide data for the development of a rational design procedure for such connections in seismically active regions. The objective of the study is to develop a moment resistant precast concrete connection that is economical and can be easily constructed. Four one-third scale monolithic concrete beam-to-column connections were tested: two were designed according to the 1985 Uniform Building Code (UBC) Seismic Zone 2 criteria and two to UBC Zone 4 criteria. In addition, two precast, posttensioned concrete beam-to-column connections similar in design to the monolithic Zone 4 specimens were tested. These tests constitute the first phase of a multi-year test program.

Performance of Precast Concrete Beam-to-Column Connections Subject to Cyclic Loading

An experimental study of the behavior of precast concrete beam-column connections subjected to cyclic inelastic loading was initiated at the National Institute of Standards and Technology. The study was initiated to provide data for the development of a rational design procedure for such connections in high seismic regions. The objective of the study is to develop a moment resistant precast concrete connection that is economical and easily constructed. Results of the experimen~al tests of both monolithic and precast beam-column connections are described. The monolithic concrete .specimens were designed to 1985 UBC Seismic Zone 2 and 4 criteria. The design of the precast concrete specimens was similar to that for the monolithic specimen designed to UBC seismic zone 4. The results from the monolithic specimens provide a benchmark for comparison with the results from the precast test~. The experimental program is divided into three phases. This report presents the findings of the first phase of the test program. Comparisons of the performance of the monolithic beam-column joints with that of the precast joints in which the beam-to~columnconnection is provided by post-tensioning bars are presented. The effects of fiber reinforced grout between the beam and column are described. Comparisons are made between the energy dissipation, ductility, and failure mode for the two types of beam-column joints.

Performance of 1/3-Scale Model Precast Concrete Beam-Column Connections Subjected to Cyclic Inelastic Loads

Precast reinforced concrete structures are widely used due to many constructional advantages such as faster construction speed, lower construction cost, being environmentally friendly, higher strength, and so on. To study the seismic performance of precast reinforced concrete structures, tests on beam-to-column joints of precast reinforced concrete structures were conducted under low reversed cyclic loading. In total, four joint specimens were produced in this study, including two precast joints and two cast-in-place joints. In addition to the comparison between different types of joints, the axial compression ratio of column was adopted as the main variable in this study. Analysis was carried out on the basis of the observed joint failure mode and relationships derived from the test data such as hysteresis curves, skeleton curves, stiffness degradation curves, energy dissipation capacities, and sleeve joint strain curves. Despite the closeness of energy dissipation capacity between the precast joints and...

Seismic performance comparison between precast beam joints and cast-in-place beam joints:

Experimental study on seismic performance of precast LSECC/RC composite joints with U-shaped LSECC beam shells

In this article, cyclic performance of an innovative precast beam-to-column connection is evaluated experimentally and numerically. Two full-scale beam-column cross-shape interior connection specimens named PF-1 and PF-2 are tested. By adding extra nuts to the connecting bolts, specimen PF-2 behaves in more shear-dominant pattern and shows less pinching. Comparison of performance of these specimens with the numerical monolithic model in terms of stiffness, strength, ductility and energy dissipation capacity indicates the proposed system can provide conditions close to the monolithic connection. However, to reduce the pinching drawback, a minor modification was made leading to performance improvement in strength and equivalent viscous damping ratio up to 51% and 29%, respectively. The results of this study have a direct industrial relevance and may be used for development of reliable seismic guidelines for precast concrete structures.

D. W. Kirk

Papers

Ductile Beam-Column Connection in Precast Concrete