Yong Myung Park

Dynamic Shear Strength of Stirrup-reinforced Cast-in Anchors by Seismic Qualification Tests

An experimental study was conducted to evaluate the breakout strength of stirrup-reinforced cast-in anchors under dynamic shear loadings. The shear loadings were applied in the manner specified in the ACI 355.2 and ETAG 001 for the seismic qualification tests. Test specimens were fabricated with M36 anchor (edge distance, 180mm) reinforced with D10 stirrups (spacing, 100mm). The specimens reached almost the breakout strength and thereafter fracture of anchor occurred. Additional tests with M42 anchor (edge distance, 160mm) reinforced with D6 bars (spacing, 100mm) were also conducted. The experimental results showed that the dynamic shear strength was not less than the static resistance. Based on the test results, it was shown that ACI 318 and ETAG 001 specifications estimate the breakout strength of stirrup-reinforced anchors conservatively as more reinforcement is provided.

Numerical Analysis on Bending Strength and Ductility of Compact Section I-Girders with HSB800 Steels

New high performance steel HSB800 have been developed in South Korea, the yield strength of which is equal to 690MPa. High strength steels typically show a lower ductility and a larger yield ratio than conventional steels. Since the inelastic design procedure of current AASHTO specifications is not permitted to the flanges and webs of nominal yield stress exceeding 485 MPa, this study is intended to present an assessment result of the compactness requirements for I-section girders by performing 3D nonlinear finite element analyses. On the hypothetical specimens designed to be compact-section girders, the numerical analysis was performed using the finite element code ABAQUS. From the analysis results, it is found that the compact section limits speculated in the 2007 AASHTO LRFD could be applicable to the design of HSB800 steel I-girders to reach the plastic moment. However, the inelastic design procedure does not surely confirm a sufficient flexural ductility. More extensive studies of HSB800 I-girders are still in need.