Experimental investigation on the seismic performance of a novel damage-control replaceable RC beam-to-column joint

To satisfy the easy-repair demands of precast concrete (PC) frames after an earthquake, a PC frame with replaceable artificial controllable plastic hinges (ACPHs) is proposed in this paper. ACPHs were installed at each beam end on both sides of the frame, which concentrated the structural deformation to avoid any damage of precast reinforced concrete members. In this study, to explore the seismic behavior and ACPH location factor on the seismic performance of the frame structures, cyclic loading tests were conducted on two precast concrete frames with different positionings of the ACPH and cast-in-situ frame. The test results indicate that the ACPH frame exhibited favorable seismic performance, and the bearing capacity and energy dissipation capacity can be improved by appropriately extending the distance from the ACPH to the cylinder. Based on the principle of maximizing the elastic range resistance of precast reinforced concrete beams, the formulas for calculating the optimal locations of ACPHs were established. 

Experimental Research on the Seismic Performance of Precast Concrete Frame with Replaceable Artificial Controllable Plastic Hinges

Experimental investigation of a single-yielding precast concrete beam–column connection with replaceable energy-dissipation connector

Experimental study on mechanical behaviour of replaceable energy dissipation connectors for precast concrete frames

In a new type of Reduced Beam Section (RBS) connection, called the corrugated web RBS connection, the flat web of the beam in the section near the column face is replaced by corrugated plates so as to reduce the flexural strength of the beam and ensure hinge formation in this section. The use of the corrugated web in the reduced section zone increases the lateral-torsional stability of the beam and reduces its flange width-to-thickness ratio. This paper presents two new types of corrugated web RBS connection, called the curved cell web RBS (CW-RBS) and the hexagonal cell web RBS (HW-RBS). The design method is described and the seismic behavior of the connections is evaluated through finite element modeling and analysis. After validating the numerical model with the existing experimental data, a number of models created with the proposed details but for different beam and column sections and by considering three different depths for the corrugated cells are analyzed under cyclic loading. A number of control models including the radius cut RBS (RC-RBS), the accordion web RBS (AW-RBS), and the tubular web RBS (TW-RBS) connections are used for comparison. The results show that the proposed connections cause plastic hinges to emerge in the RBS zone, thereby preventing failure at the beam-column junction. The proposed connections offer stable hysteretic behavior with better ductility and lower strength degradation than the conventional RC-RBS connection. The proposed connections also develop significantly lower maximum equivalent plastic strains than both AW-RBS and TW-RBS, which can delay the failure of the beam in the RBS zone.

Two novel corrugated web reduced beam section connections for steel moment frames

A type of replaceable energy-dissipation connector - precast concrete frame is proposed, in which the replaceable energy dissipation connectors are assembled on the upper and lower sides of the beam end with a direct load-transfer path. The connectors can induce plastic deformation of the frame concentrated in the connectors themselves, while the main structural members, such as beams and columns, can remain elastic under strong earthquakes. Additionally, the seismic rehabilitation of the frame could be easily achieved by replacing the damaged connectors. Pseudo-static tests on an exterior beam-column joint of the frame were conducted, including the initial working condition and the seismic rehabilitation working condition. The test results revealed that a stable hysteretic property could be obtained in the joint, while a high energy-dissipation capacity was also confirmed. Plastic deformation was concentrated in the connectors, while a few cracks could be seen in the concrete components. The seismic rehabilitation working condition revealed that the initial stiffness and the hysteretic property could remain the same as those of the initial working condition. The formula for the initial rotational stiffness of the joints is derived at the end of the paper, indicating that the calculated results of the test specimens are consistent with the test results.

Luqi Xie

Papers

Experimental study of mechanical properties of beam-column joint of a replaceable energy-dissipation connector-precast concrete frame

Experimental study on mechanical behaviour of replaceable energy dissipation connectors for precast concrete frames

Seismic performance of buckling-restrained reduced beam section connection for steel frames