| Project/Area Number |
62550341
|
|---|
| Research Category |
Grant-in-Aid for General Scientific Research (C)
|
| Allocation Type | Single-year Grants |
|---|
| Research Field |
土木構造
|
|---|
| Research Institution | KUMAMOTO UNIVERSITY |
|---|
Principal Investigator |
HIRAI Itio College of Engineering, Kumamoto University, 工学部, 教授 (60040367)
|
|---|
| Co-Investigator(Kenkyū-buntansha) |
YAMAO Toshitaka College of Engineering, Kumamoto University, 工学部, 助教授 (40109674)
OHTSU Masayasu College of Engineering, Kumamoto University, 工学部, 助教授 (80109016)
梶川 靖治 川田建設(株), 工事本部, 開発室長
SAKIMOTO Tatsuro College of Engineering, Kumamoto University, 工学部, 教授 (50029302)
KAJIKAWA Yasuharu Construction Division, Kawata Kensetsu co.
|
|---|
| Project Period (FY) |
1987 – 1988
|
| Project Status |
Completed (Fiscal Year 1988)
|
| Budget Amount *help |
¥2,100,000 (Direct Cost: ¥2,100,000)
Fiscal Year 1988: ¥600,000 (Direct Cost: ¥600,000)
Fiscal Year 1987: ¥1,500,000 (Direct Cost: ¥1,500,000)
|
|---|
| Keywords | Mixed Structures / Jointed Beams / Joint / Ultimate Strength / プレストレス / 継手 / 鋼コンクリート混合構造 / 応力集中 / 曲げ耐荷力 |
|---|
| Research Abstract |
Experiments for steel-concrete jointed beams subjected to pure bending or shear and bending or pure shear are carried out to clarify the ultimate strength of joint and to explore the possibility of developing the utilization of steel-concrete mixed structures. A steel plate welded to the end of steel H-beam is jointed to a reinforced concrete beam of rectangular cross-section by prestressing steel bars.
Attention is focused on evaluating the effects of the end plate thickness and of connecting steel bars which is welded to the end plate surface of concrete side and joins steel and concrete beams.
Main conclusions obtained are as follows:
1) The ultimate bending capacity under pure bending or under bending with shear is controlled by the compres-sive failure of the concrete at the upper part adjacent to the end plate. therefore, it is importhat to install the plate of sufficient thickness in order to distribute and transmit the normal stress from upper flange of steel beam to concrete beam
… More
. If the thickness of the end plate is small, the bending strength of the beam decreases remarkably due to the stress concentration. The thickness of the end plate which ensure the required bending capacity can be determined by keeping the bending stress of the end plate due to concentrated load from the prestressing bars to be less than the yield point stress. In this case, the end plate is considered to be a plate clamped at upper and lower flanges.
2) The ultimate bending strength of the joint with end plate of sufficient thickness can be controlled by changing the magnitude of prestressing and the diameter of connecting bars and can be estimated accurately by the modified formula based on the ordinary stress block model.
3) Shear resistance of the joint can be estimated as the sum of resistances of concrete itself, friction force between the end plate and concrete, and prestressing bars. The shear resistance of the prestressing bars and that by friction force are large, but depends on the magnitude of the prestressing force.
4) For more accurate estimation of shear resistance, further tests are needed. But, generally for the joints used herein, the ultimate strength of the jointed beam will be controlled by the bending capacity. It will be recomended to take the load which gives the de-compression monent as the design load of the beam. For that case, as for the specimens tested here, the safety factors are 1.3 and 3.0 for the monent where cracks initiate and for ultimate bending failure, respectively. Less
|
