Post-tensioned self-centering moment connections with beam bottom flange energy dissipators

2009 ◽  
Vol 65 (10-11) ◽  
pp. 1931-1941 ◽  
Author(s):  
Chung-Che Chou ◽  
Yu-Jen Lai
Keyword(s):  
Bottom Flange ◽  
Moment Connections ◽  
Energy Dissipators ◽  
Post Tensioned

Cyclic performance of existing moment connections in steel retrofitted with a reduced beam section and bottom flange reinforcements

2007 ◽  
Vol 34 (2) ◽  
pp. 199-209 ◽  
Author(s):  
Sang-Hoon Oh ◽  
Young-Ju Kim ◽  
Tae-Sup Moon
Keyword(s):  
Plastic Hinge ◽  
Composite Beams ◽  
Bottom Flange ◽  
Deformation Capacity ◽  
Moment Connections ◽  
Element Analysis ◽  
Reduced Beam Section ◽  
Steel Shape ◽  
The Face ◽  
Beam Section

This study investigated the effectiveness of retrofit methods in improving the deformation capacity of existing moment connections in composite beams. Nonlinear finite element analysis was also performed to identify the cause of the connection failure prior to testing. Tests included one conventional specimen and four retrofit specimens. Three retrofit methods were introduced: a reduced beam section (RBS) only, an RBS with bottom flange reinforcement (RBR), and an RBS-shaped bottom flange reinforcement (RSR). A composite beam performs differently than a bare steel shape because the concrete compression flange greatly increases the tensile demands on an unreinforced bottom flange. Therefore, these retrofit methods were applied only to the bottom flanges of the beam. Quasi-static loading tests were performed. The main conclusions were as follows: (i) the deformation capacity of the existing moment connections in composite beams is not sufficiently improved by RBS alone; and (ii) both the RBR and RSR details move the plastic hinge away from the face of the column and reduce stress levels in the vicinity of the beam bottom flanges, sufficiently improving the deformation capacity.Key words: composite construction, seismic performance, reduced beam section (RBS), flange reinforcement, ductility, deformation capacity.

Effects of Different Bolted Connection Types on Seismic Performance of Column-Tree Steel Moment Connections

2013 ◽  
Vol 753-755 ◽  
pp. 581-584
Author(s):  
Kang Min Lee ◽  
Keun Yeong Oh ◽  
Liu Yi Chen ◽  
Rui Li
Keyword(s):  
Seismic Performance ◽  
Bottom Flange ◽  
Moment Connections ◽  
Bolted Connection ◽  
Drift Ratio ◽  
Hole Area ◽  
Story Drift ◽  
Moment Resisting ◽  
Scale Test ◽  
Ductile Behavior

This paper experimentally presents the effects of different bolted connection types on the seismic performance of column-tree steel moment connections used in moment resisting frames. Two full scale test specimens were fabricated and tested: one specimen with slip critical bolted beam splices and the other one with bearing type bolted beam splices. The bearing type splice specimen was expected an improved deformation capacity by means of bolt slippage. The experimental results showed that the slip critical splice specimen successfully developed ductile behavior without brittle fracture until 5% story drift ratio, however for the bearing type splice specimen, the beam bottom flange fractured at 4.0% story drift ratio due to stress concentration around the weld access hole area. However the energy dissipation capacity of the bearing type splice specimen was better than that of the slip critical splice specimen until 4.0% story drift ratio.

Structural Performance of Post-Tensioned CLT Shear Walls with Energy Dissipators

2020 ◽  
Vol 146 (4) ◽  
pp. 04020035 ◽  
Author(s):  
Zhiyong Chen ◽  
Marjan Popovski ◽  
Asif Iqbal
Keyword(s):  
Shear Walls ◽  
Structural Performance ◽  
Energy Dissipators ◽  
Post Tensioned

scholarly journals Cyclic Behavior of Steel Beam-to-Column Moment Connections Using Different Sizes of Flange Plates and Reinforced by a Single Rib Plate

2018 ◽  
Vol 4 (1) ◽  
pp. 138
Author(s):  
Abbas Haghollahi ◽  
Hassan Ahmadi
Keyword(s):  
Numerical Study ◽  
Plastic Hinge ◽  
Equivalent Plastic Strain ◽  
Cyclic Behavior ◽  
Bottom Flange ◽  
Moment Frames ◽  
Moment Connections ◽  
Element Analysis ◽  
Beam Geometry ◽  
Special Moment Frames

This paper presents a numerical study on the behavior of connection between steel I-beam and H-column when are affected by cyclic loading. The connection used the flange plates to connect the beam flanges to the column flange. They were welded to the top and bottom flange plates and created a welded flange plate (WFP) connection. Specimens were six models of WFP connections with different beam geometry and flange plate sizes which were modeled and their cyclic behavior were investigated using finite element analysis in ABAQUS program. Three of them were reinforced by a vertical triangular top and bottom rib plates, and others remained unreinforced. The results showed that reinforcement with a vertical triangular rib plate attached to the top and bottom flange plates can improve cyclic behavior of WFP connections.  By using a rib plate, the equivalent plastic strain was increased and showed better plastic hinge formation compared to those with no vertical rib plate. Those models with IPB beam sections had the best cyclic behavior compared to those with IPE beam sections and satisfied the acceptance criteria of AISC seismic provisions for intermediate and special moment frames. We concluded that those WFP connections which did not satisfy the criteria of AISC seismic provisions for special moment frames, can be upgraded by a vertical triangular rib plate in order to be used in special moment frames.

Single-electron sensitivity with a lens-coupled CCD camera

1993 ◽  
Vol 51 ◽  
pp. 642-643
Author(s):  
G.Y. Fan ◽  
Bruce Mrosko ◽  
Mark H. Ellisman
Keyword(s):  
Focal Length ◽  
Thick Layer ◽  
Ccd Camera ◽  
Single Electron ◽  
Bottom Flange ◽  
X Rays ◽  
Red Phosphor ◽  
Ccd Detector ◽  
Lens Assembly ◽  
Efficient Coupling

A lens coupled CCD camera showing single electron sensitivity has been built for TEM applications. The design is illustrated in Fig. 1. The bottom flange of a JEM-4000EX microscope is replaced by a special flange which carries a large rectangular leaded glass window, 22 mm thick. A 20 μm thick layer of red phosphor is coated on the window, and the entire window is sputter-coated with a thin layer of Au/Pt. A two-lens relay system is used to provide efficient coupling between the image on the phosphor scintillator and the CCD imager. An f1.0 lens (Goerz optical) with front focal length 71.6 mm is used as the collector. A mirror prism, of the Amici type, is used to "bend" the optical path by 90° to prevent X-rays which may penetrate the leaded glass from hitting the CCD detector. Images may be relayed directly to the camera (1:1) or demagnified by a factor of up to 3:1 by moving the lens assembly.

Practice of Partial Prestressing for Continuous Post-Tensioned Structures in North America

PCI Journal ◽  
1985 ◽  
Vol 30 (1) ◽  
pp. 154-182
Author(s):  
Clifford L. Freyermuth
Keyword(s):  
North America ◽  
Post Tensioned

Serviceability Behavior of Post-Tensioned Beams

PCI Journal ◽  
1980 ◽  
Vol 25 (1) ◽  
pp. 75-95 ◽  
Author(s):  
Edward G. Nawy ◽  
Jim Y. Chiang
Keyword(s):  
Post Tensioned
Sign in / Sign up

Export Citation Format

Share Document