In recent years, sufficient measures to prevent vibration-noise along our country's roads have been in highdemand. One of the measures implemented to help prevent this problem occurring, uses a method of construction in which the floor slab of a bridge is extended onto the topsoil at the back of an abutment pier, and has been carried out by the former JH. This measure, named the' extension floor slab' method of construction, can reduce the vibration-noise by separating the joints along which most vibration occurs. An independent administrative agency; the Public Works Research Institute (PWRI), and a corporate judicial body; Japan Bridge Association (JBA), performed a collaboration study for several years about this method of construction. PWRI and JBA applied this method of construction to the existing Tokonami Bridge, along National Highway No.49. In this article, we report on the application of our new method of construction and its design.
Making the construction procedures of steel pipe piles more rational and rapid, anew type mechanical joint for steel pipe piles and steel pipe sheet piles were proposed. In order to investigate the corrosion resistant performance of the mechanical joint, three types of exposure tests were carried out, namely, (1) Exposure test on steel materials used for the joint and piles, (2) Bimetal corrosion test on the joint material and the pile material, and (3) Exposure test on the joining surface of the joint under the marine environment. As the result of these tests, it was confirmed that the corrosion resistance performance of the joint material is the same as that of the pile material under the soil surrounding conditions. However, under the marine conditions, the corrosion resistance performance of the joint material is lower than that of the pile material. Moreover, it was confirmed that the joining surface of the mechanical joint has great corrosion resistance performance even if it is in the marine conditions.
To secure the durability of the continuous composite girder bridges, the crack control method by pc bars or stress control methods by prestressing are generally adopted for the tensile stresses induced to the concrete-slab at an intermediate support. For the stress control methods by the prestressing, i.e. jack-up-down method and method by prestressing pc bars are popular ones. However, both the methods are effective against the serviceability limit state, but not sufficient against the ultimate limit state of bridges. In order to improve the ultimate limit state, a thermal prestressing method was investigated in this paper. Particulaly, the effects of creep and shrinkage on the variations of stresses induced through the thermal prestressing method were detailed by illustrating the affections for a continuous composite girder bridge with two spans. Also suitable time and amount of additional prestressing are discussed herein.
In this paper the static characteristics of WF beam-to-CFT column connections using special shaped high strength rods and nuts were investigated. The rod is penetrating column and connecting nuts. In order to investigate the strength and local deformation of special shaped high strength rods and nuts connections, the tensile test is executed.From these test results stress transfer mechanism of a rod resisted to tension became clear.
This paper discusses simulation of dynamic collapsing behavior of a four-story steel building that is scheduled to be tested by E-Defense. Two-dimensional analyses utilizing beam and column elements with plastic hinges are conducted. The trends of collapsing responses and their dependencies on structural parameters are demonstrated. It is concluded that the collapsing behavior of the specimen is mainly governed by the deteriorating behavior of rectangular tube columns induced by local buckling.
Making the construction procedures of short span bridges more rational and economical, the slab bridge composed of steel square tubes was proposed. Ensuring the durability of the bridge, fatigue life evaluation was required. In order to investigate the fatigue life of steel square tubes composing the proposed slab bridge, fatigue tests on steel square tubes were conducted. As a result of these tests, it is confirmed that the fatigue strength of steel square tube composing the proposed slab bridge can be evaluated as the Category C of JSSC fatigue design guideline.