The series of tests had been done in order to make resistant ability of steel tube member better against impact action as like a rock fall. Outside members were steel tubes in which were arranged by some small steel tubes and fulfilled by mortar around those tubes. Static loading tests and impact tests by the free fall of a heavy weight were achieved. Characteristics of those members had been investigated by results of tests and theoretical calculations using section sprit method. Finally, the equation to estimate the energy absorption of those steel tubes under impact concretely had been proposed.
This paper investigates both the earthquake resistant performance and dynamic behaviors of steel frame structures with self strain stresses due to relative settlement of the structures or thermal stress within the structures. And, this paper concludes as follows: (1) the horizontal stiffness of steel frame structures tend to reduce as the self strain stress increases. And (2) this reduction contributes to increase dynamic response of the steel frame structures subjected to severe earthquake. Therefore (3) the increases of the self strain stress effect on the earthquake resistant performance of the steel frame structures.
In Japan, as so many highway bridges constructed in the last four decades became superannuated, maintenance of those bridges has become the most serious problem to extend the service lives with appropriate rehabilitation works. For the slabs, replacement of severely deteriorated slabs is a recent trend to minimum the LCC. The authors developed a rationalized joint for precast steel concrete composite decks that could shorten the construction period by reducing the joint width accompanying with decrease of concrete volume and placing re-bars. In this paper, through verification tests for the joints, characteristics of concrete cracks, stress transmission of re-bars and applicability for actual bridges, were confirmed.
Fatigue tests of plates with gussets welded to the plate edges were fatigue tested under plate bending type of loading. When fatigue cracks initiated and propagated from the gusset ends, Impact Crack Closure Retrofit treatment, ICR treatments, were applied to the cracks in order to stop or to reduce further fatigue crack propagation. The ICR treatment is the technique to produce plastic deformation near the fatigue cracks to close opening of the crack, and thus reduce stress intensity factor. Fatigue test results showed significant improvement of remaining fatigue life after ICR treatment.
Concrete filled elliptical steel tubular, abbreviated in CFEST, structure is similar to a concrete filled tubular, so-called CFT structure and a new type of structural member consists of elliptical steel tube and in-filled concrete. Purpose of this study is to investigate centric loading characteristics of CFEST experimentally. Influence of diameter-to-thickness ratio, 2b/t(2a/t), on axially loading capacities of CFEST is mainly discussed. Furthermore, biaxial stress of the elliptical steel tube induced into core concrete is also mentioned. As a result, it can be found that axially loading capacities are affected by the ratio 2b/t(2a/t).