Seismic Performance of Precast Concrete Beam-Column Connections Using Ductile Rod

Abstract

Precast concrete (PC) beam-column connections using ductile rods are proposed for earthquake zone. An existing beam-column connection, two PC specimens designed by considering failure modes and a conventional RC specimen were tested under cyclic loading to evaluate the seismic performance. The specimens were designed to satisfy the requirements of current design code. The variables are the yield strength of longitudinal reinforcing bars of PC beams. The test results showed that the proposed system applying smaller yield strength of the longitudinal reinforcing bars at the PC beams than the ductile rods was satisfied with seismic criteria. The deformation capacity and energy dissipation capacity of the proposed PC beam-column connections were greater than those of the existing DDC system.

Minimum Joint Depth for Moment Frames with High- Strength Materials

“…29 The bars also satisfied ACI 318-19 9 requirements for Grade 100 (690) bars used in earthquake-resistant special structural walls. 20,22,25 of interior beam-column joints with Grade 100 (690) threaded bars (with a relative rib area 28 of 0.18), the reinforcement used in this study had bar deformations similar to those common in the United States (the relative rib area 28 was 0.10).…”

“…Table 4 reports that V j,m /V n,m was 0.77 for A and between 0.86 and 0.94 for B, C, and D. Lee et al 22 observed that connections with V j,m /V n,m ≤ 0.8, such as Specimen A, normally exhibit a response dominated by beam flexural hinging, and that joints with V j,m /V n,m close to but not exceeding 1.0, such as Specimens B, C, and D, normally exhibit a joint shear failure in drift cycles of 4 to 6% after beam-bar yielding. This is consistent with the extensive inclined cracking observed in B, C, and D after loading to a 4% drift ratio, described previously.…”

“…Recent studies have demonstrated that the use of high-strength bars in place of Grade 60 (420) longitudinal bars results in acceptable interior joint behavior. [22][23][24][25] Prior work 26 has also shown that ACI 318-19 9 provisions for joint shear strength are applicable to joints with Grade 100 (690) bars. This prior work did not, however, resolve the issue of beam reinforcement bond within the joint because all prior tests of beam-column joints with Grade 100 (690) bars that the authors are aware of used the threaded bars 27 common in Taiwan and Japan.…”