JP2010007401A - Ladder-like vibrational energy absorber for wooden building - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To solve a problem wherein a ladder-like reinforcing member for use in a conventional wooden building reinforcing technology is a strength resisting type device with a defect of being not resistible to second force onward once experiencing large force and deformation, and when repeatedly swayed in an earthquake or the like, a subsequent earthquake-resistant effect cannot be expected once exceeding the design load of the device, and its cause is in slip type restoring force characteristics. <P>SOLUTION: A ladder-like vibrational energy absorber is composed of ladder step members and ladder handrail members. The ladder step member is formed as a hysteresis energy absorber, and the ladder handrail member is formed as an elastic member to clearly divide each role. A plate is used to join the ladder step member and the ladder handrail member in order to concentrate the hysteresis energy absorption of the ladder step member on both ends of the member. Further, the ladder-like vibrational energy absorber is assembled to form an H-shaped cross section and a biaxially symmetrical closed section to restrain the deformation of an intermediate part of the ladder step member. Plastic deformation can thereby be concentrated on both ends of the ladder step member to attain excellent restoring force characteristics as the device. <P>COPYRIGHT: (C)2010,JPO&INPIT

Description

  The present invention relates to an anti-seismic and vibration-damping member for preventing collapse of a wooden building having a relatively small horizontal rigidity and a large variation as represented by a traditional wooden building.

  The policy for improving the earthquake resistance of buildings can be broadly divided into strength-oriented type, toughness-oriented type, or mixed type. One of the strength-oriented seismic reinforcement techniques for traditional wooden frames is to install wooden ladder frames between existing columns. This technique supports a pair of left and right pillars that are inclined with respect to a horizontal load such as seismic motion with a ladder-type frame (Non-patent Document 1, Japanese Patent Application 2005-335318).

  In these existing technologies, the ladder handrail member and the ladder step member are inserted and joined, and the restoring force characteristic that is important for the seismic performance is the slip type. (Non-Patent Document 1) shows an insertion-type load resistance model in FIG. 12, and FIGS. 4, 5, and 6 show restoring force characteristics obtained by experiments.

In Japanese Patent Application No. 2005-335318, each type of restoring force characteristic is shown in FIG. 12, but all are of the slip type.
Masakatsu Okamura, Yoshiyuki Suzuki, Tatsushi Suda, Hidemitsu Tanahashi, Restoring Force Characteristics and Resistance Mechanism of Ladder-type Frames, Abstracts of Annual Conference of Architectural Institute of Japan (Kyushu) August 2007, pp.433-434. Japanese Patent Application No. 2005-335318 (Reinforcing members for wooden structures and reinforcement methods using them)

  As described above, when the type of connection between the ladder handrail member and the ladder step member is a plug-in type, and the strength-oriented seismic reinforcement technology is used, once a large force and deformation caused by it are experienced, it is almost resistant to the second and subsequent forces. Unable to deform a wooden building.

  An object of the present invention is to realize a device having a high vibration energy absorption capacity by improving the restoring force characteristics of a slip type in order to aim at a toughness-oriented type seismic reinforcement technology instead of a strength-oriented type.

  It aims to realize easy replacement of damaged parts and low price, which is indispensable for toughness-oriented seismic reinforcement technology.

  The role of the ladder step member is a hysteresis energy absorbing member, and the ladder handrail member is an elastic member.

  The ladder step member and the ladder handrail member are joined with a wood screw or a bolt. This eliminates the slip-type restoring force characteristic caused by local plastic deformation due to contact between the components.

  The ladder step member has two configurations, one on both ends and one on the middle, so that plastic deformation is concentrated on both ends.

  The present invention can realize a good restoring force characteristic by clarifying the roles of the handrail portion and the ladder step portion of the ladder-like device.

  In addition, replacement of damaged members is easy and the construction is simple, so that the manufacturing price can be kept low.

  Hereinafter, embodiments of the present invention will be described with reference to FIGS.

  FIG. 1 and FIG. 2 show the situation where they are installed in the axial structure of a wooden building. The member a in the figure is a hysteresis energy absorber (ladder step member), and the member b is a ladder handrail member. In the case of FIG. 1, securing the frontage takes priority, and FIG. 2 is a case prioritizing securing the height.

  FIG. 3 shows a hysteresis energy absorber (ladder step member a). The upper and lower ends of the member are flat plates joined to the ladder handrail member b by bolts or screwing. A member connecting the flat plates at both ends is a flat plate, and flat plates are attached to the middle portion so as to form H-shaped cross sections on both sides in order to reduce bending deformation. Accordingly, the relative horizontal deformation of the upper and lower ends is concentrated on the flat plate at the end.

  FIG. 4 similarly shows a hysteresis energy absorber (ladder step member a). A difference from FIG. 3 is that a closed cross-section member is used to suppress deformation of the intermediate portion. As an example, a square box cross-section member is used as a closed cross-section member to cover a flat plate connecting both ends. A circular pipe member may be used as the closed section member.

  3 and 4 are processed with a metal material having excellent toughness, and the assembly of the members is performed by welding. Since the material is limited to flat cross-section members such as flat plates, box shapes, and circles, commercially available products can be used, and the dimensions can be freely adjusted according to the required performance.

  Since the ladder handrail member b remains within the elasticity, only the ladder step member a can be replaced after the earthquake. Each part can be brought in and assembled locally, so workability is good.

  The ladder step member is also installed as a vibration energy absorbing member by installing between existing pillars or beams of the building.

Elevated view installed horizontally on a traditional wooden frame Elevated view installed vertically on a traditional wooden frame Example 1 of ladder steps Example 2 of ladder steps

Explanation of symbols

a ... Ladder step member of ladder-like vibration energy absorber
b ・ ・ ・ Handrail member of ladder-like vibration energy absorber

Claims (5)

  Ladder-like vibration energy absorption device for wooden building, which has a ladder step member and a ladder handrail member, the ladder step member as a hysteresis energy absorption device, and the ladder handrail member as an elastic member, clearly divided in their roles .   The ladder-like structure of a wooden building according to claim 1, wherein the ladder step member and the ladder handrail member are joined by wood screws or bolts, thereby eliminating slip-type restoring force characteristics caused by local plastic deformation caused by contact between the constituent members. Vibration energy absorber.   The ladder-like vibration energy absorbing device for a wooden building according to claim 1 or 2, wherein the ladder step member has two configurations of both end portions and an intermediate portion so that plastic deformation is concentrated at both end portions.   The ladder-like vibration energy absorbing device for a wooden building according to any one of claims 1 to 3, wherein the hysteresis energy absorbing portion at the end of the ladder step member is a flat plate. The ladder-like vibration energy absorbing device for a wooden building according to any one of claims 1 to 4, wherein an intermediate portion of the ladder step member is constituted by a flat plate and a closed cross-section member.