-
ings subjected to lateral loads, and that they may require specific design treatment following the accepted design philosophy of the strong-column weak-beam. In earthquake-prone regions, the joints must be designed to allow the dissipation of large amounts of energy into the neighbouring elements without a significant loss of strength and ductility. The frames are often designed carefully based on the strong-column–weak-beam concept and their joints detailed accordingly. Sometimes, though, the detailing is inadequate (example, RC joints designed to earlier codes have insufficient lateral resistance).Web-bonded FRP (fibre reinforced plastic) is one of the few possible strengthening methods that can be used when an inadequately detailed joint is damaged causing severe degradation of the joint’s structural strength. In this paper, the results of some tests on FRP strengthened specimens are presented. The results show that the method is effective and capable of restoring or even upgrading the strength of the system. In addition, using the basic principles of equilibrium and compatibility, an analytical model is presented that simplifies the analysis and design of this strengthening scheme. Based on the model, a range of design graphs are presented for selection of the type and the amount of FRP required upgrading an existing joint to a specified moment capacity and curvature ductility.23587
- 上一篇：注射模具英文文献及中文翻译
- 下一篇：蜗轮蜗杆的磨损形式英文文献和中文翻译
Crown Copyright 2009 Published by Elsevier Ltd. All rights reserved. 1. Introduction
Beam–column joints are critical regions of reinforced concrete
frames designed for inelastic response to seismic attack. Inade-
quately detailed joints, especially exterior beam–column joints,
may fail prematurely in a brittle manner due to high shear stresses.
In earthquake-prone regions, the joints of ductile moment resisting
(DMR) frames must be designed and detailed to allow large energy
dissipation in adjacent plastic hinges without a significant loss of
strength and ductility. Designing beam–column joints is consid-
ered to be a complex and challenging task for structural engineers,
and careful design of joints in RC frame structures is crucial to the
safety of the structure. Although the size of the joint is controlled
by the size of the framemembers, joints are subjected to a different
set of loads from those used in designing beams and columns. As a
result, it is necessary to pay special attention to the detailing of
reinforcement within a joint region.When frames are not designed
properly, the possibility of plastic hinge formation in the columns
increases. This is not desirable for two reasons: firstly, the collapsemechanism associated with hinges in the columns has a lower ulti-
mate load; and secondly, the energy absorption of plastic hinges
within the columns is normally less due to reinforcement arrange-
ment and the axial load [1]. Engineers can avoid this when
designing DMR frames by employing the principle of strong-
column–weak-beam design. According to this design principle,
joints, columns and beams are designed so that the joint region
and the column remain essentially elastic under the action of high
lateral loads, such as earthquake and high-pressure winds, while
themain energy dissipation occurswithin the plastic hinges formed
in the beams. Care also should be taken to make sure that plastic
hinges within the beam are sufficiently distanced away from the
joint. This is to ensure that penetration of plasticity to the joint core
will not occur, as this may trigger a brittle failure within the core.
There are several traditional ways of achieving this [1,2].
In each of the following two scenarios, rehabilitation may be-
come necessary within the beam region adjacent to a joint: (i) RE-
PAIR, when after a moderately large earthquake, visibly annoying