This study experimented hip rafter member by reinforcing damaged wood due to structural causes in traditional wooden structure with steel plate and the following structural behaviors and reinforcement effects were examined.
1) As a result of hip rafter member, the specimen that the damaged wood was reinforced with steel plate was expected to have reinforcement effects in yield load, ultimate load and increase of initial and plastic region stiffness.
Non-reinforced standard specimen had flexural crack at the upper part from initial period of loading and progressed to destruction, but specimen reinforced with steel plate showed deflection by bending from the left side of the specimen due to reinforcement effect and bending failure or damage of reinforcing materials were found. Therefore, it was considered that reinforcement effects were exerted from the initial load after reinforcement.
2) Reinforced specimen showed 2~45% increase of yield load and 6~73% increase of ultimate load compared to standard specimen and the reinforcement effects were confirmed.
3) The reinforcement of steel plate in reinforced specimen increased structural reinforcement effects including yield load and ultimate load by reinforcement using bolt and nail rather than using only bolt.
4) Ductility factor of the specimen reinforced by standard specimen was 7~13% reduced in I type and was similar to that of II Type and III Type. It was considered that the specimen reinforced with steel plate showed increase of load but no great increase of deflection after yield load.
5) The stiffness of the reinforced specimen showed 27~36% increase in III Type compared to standard specimen and I Type and II Type showed similar or a little reduced stiffness to the standard specimen. In addition, the stiffness of plastic region was increased as the protruded length ratio increased and the load tended to be increased compared to the increase of deflection after yield load.
6) External deflection control effect in III Type with the longest protruded length of the reinforced specimen was similar to the standard specimen, but the internal lift control effect was 23~25% increased.
As a result of reinforcement experiment to hip rafter member with the damage on hipped-and-gabled roof of traditional wooden structure using steel plate, it was found that reinforcement using steel plate was expected to bring about increase of stiffness of initial and plastic region, ductility, yield load and ultimate load.
In addition, as the reinforcement using steel plate could accomplish internal lift control effects of hip rafter, the reinforcement by combining encased carbon bar, steel plate, bolt and nail on the properties of natural wood will be desirable.