In this paper, the results of slip tests on high strength bolted joints with normal 0.45 slip coefficient are herein. And the quantity of transferred friction force between a member and splice plate in the front side of bolt hole is considered from the results. From the consideration, it is clarified that on the average the transferred friction force in the front side of bolt hole is 36% of the design slip strength on a high strength bolt.
This study is planed to clear the behaviour of friction joints with high strength bolts on web bolted flange welded (WBFW) connections. In this study, web bolted connnection with high-strength bolts (WB) is tested. FEA is carried out and compared with the test result for considering the correctness of PEA procedure. The results are briefly shown: FEA result shows good correspondence with the test elasto-plastic behaviour of the friction joints. After the bolts contact with the plate, load which born by friction part decreased and the bearing load of the bolts increased.
Corrosion prevention properties of cable pastes (red lead paste, calcium plumbate paste and aluminium phosphate paste) are investigated. Moisture permeability of the pastes is two-hundredth of that with no paste. The effects of these pastes on galvanized wire are compared by salt spray test and immersion test contacting with degradation paste. Aluminium phosphate paste has good corrosion control, but red lead paste and calcium plumbate paste are not good with metal lead in the corrosion product. Inhibitor of paste-components affects corrosion prevention ability, and those with neutral property and without electrical positive metal such as lead are better.
A new corrosion prevention system has been developed S-shaped wire wrapping with elastic type heavy duty coating (epoxy resin primer and fluorine top coats). The system intercepts corrosion factors such as water into the cable. S-shaped wire wrapping has better waterproof than general galvanized wires with a circle cross section. Elastic type heavy duty coating has good adhesive on new galvanized surfaces and has high corrosion prevention property, which was confirmed by weatherproof corrosion tests and immersion tests. It is shown by freeze-thaw cycle tests with small-sized cable specimens that the system prevents cracks even when the cable moves longitudinally.
Two series test of the exposed-type column base were carried out to discuss relation of bending moment-rotation curve under variable axial force. One is subjected to axial load proportional to horizontal force and the other is proportional to beam shear force. The unbonded type anchor bolts are used for all specimens. Based on the test results, secant rigidity in elastic region of the anchor bolts and ultimate strength after yielding of anchor bolts are discussed. Finally model of bending moment-rotation curve is proposed.
Maximum stress obtained by compression test of circular steel stub-columns were compared with deformation theory and incremental stress-strain theory. Each buckling analysis has a term of tangent modules Et in its solution. Therefore these solutions mean that all specimens buckle in the plastic-flow range before strain-hardening regionregardless of its diameter-to-thickness ratio. In spite of these theories, it is shown that specimens with small diameter-to-thickness ratio can be compressed into the strain-hardening range. Furthermore the efficiency of endurance of compressive force is referred between box-section and circular section steel stub-columns.
The behavior of upper-deck steel arch bridges in severe earthquakes is quite complex and dynamic analysis is usually necessary for seismic designs or retrofits. By involving some recent advances in seismic design of steel piers, this study proposes a new type of such bridge structures with better seismic performance and lower cost, based on dynamic analysis results using elaborate models to account for the arch ribs and stiffening girders. In this proposed structural type, box section is adopted for all members of the bridge to employ the advanced seismic design techniques developed for box-sectioned steel piers. Moreover, to lower the cost, the proposed structure type is exempt from using the isolation bearings or dampers.
Many structural control systems have been demonstrated to reduce the response during an earthquake and have gradually been applied to buildings. However, almost all the systems have required closure of the inter-column opening in order to install the damping devices. The authors have proposed a structural control system using non-structural members for steel buildings. This system is composed of non-structural members, which are short span beams. These members as hysteretis dampers absorb vibrational energy by their hysteretic damping performance. In this paper, the earthquake response analysis of the steel building has been carried out in order to under stand the behavior of the proposed system. As the result, the usefulness of the system has been discussed.
This study is concerned with the demand for ductility of beams in steel moment frames. Numerical response analysis was carried out for 15 frames against a variety of ground motions. This paper (Part 1) describes the magnitude of plastic deformation introduced into beam-ends. Maximum plastic rotation, maximum increment of plastic rotation during a half cycle of vibration, and the range of variable plastic rotation are considered as the parameters that represent the magnitude of plastic deformation. The results are summarized as formulas to predict those parameters based on maximum story drift angles.
The previous paper (Part 1) described the magnitude of plastic deformation introduced into beam-ends. In this paper (Part 2), based on the same numerical results, we deal with hysteretic behavior. Cumulative plastic rotation, the increment of plastic rotation during each half cycle of vibration, and the hysteretic process of plastic rotation are discussed. A method is proposed to approximate damage to the beams in steel moment frames subjected to strong ground motions.
The Building Standard Law was revised and the notification No. 1464 was enacted. The permissible value over manufacture accuracy or a surface defect is specified for performance reservation of the welding joint, and when the fault exceeding occured, the reinforcement and repair which ensure the performance demanded by design should be carried out. The defective evaluation method of a welding part, and the reinforcement and the repair method are examined by AW official approval conference. It will the result investigated about the actual condition of the repair method from the questionnaire to a steel fabricater.
Due to the Geiyo Earthquake in March 24th, 2001, center stay rods of the 1st Kurushimakaikyo Bridge(suspension bridge) were broken. They were designed to break in strong earthquake and work as safety valve of the structure. In order to evaluate the mechanism of the breakage of the rods, data from field measurement were processed using structural analysis, and it was confirmed that the broken rods worked as designed. It also was confirmed that forces acted to other unbroken rods in 2nd and 3rd Kurushimakaikyo Bridges were not large enough to affect their soundness. Through this experience, it was proven that field measurements and structural analysis can be effective tools not only for design but also for maintenance of structures.