This paper indicates test and analysis results of the new oil damper, “Oil Damper with Stiffness”. It was developed to solve some issues about seismic retrofit. There are difficulties to reinforce buildings which are designed by the Old Buildings Standards Act before 1981.
Especially, factory and warehouse buildings have low stiffness. Therefore, it is prevailing to retrofit old building using braces and oil dampers, but this way requires many reinforced areas.
This paper also indicates the analysis model of the damper and effectiveness from the results of time history response analysis using a S.D.O.F. model.
In the precast reinforced high-strength spun concrete piles, (PRC piles), a numerical model on ultimate flexural condition has not been established when PRC piles have high axial force. The numerical analysis using a multi-spring model was conducted to reproduce the experimental results of six PRC pile specimens with axial force ratio ranging 0~0.313 in compression. The backbone curves of lateral load−drift angle relations were well simulated with this numerical model until ultimate condition. Furthermore, the scale effect was also investigated to see the moment capacity and post peak behavior from parametric study.
A hybrid beam, consisting of a precast prestressed concrete (PCaPC) beam reinforced with glulam timber, has been proposed. Wood screws half driven into glulam timber were embedded into concrete beam, and its timber and concrete were connected with the screws as shear connection. A full-scale bending test of two beams with openings for equipment, such as ducts, were conducted, and it was confirmed that initial stiffness increased by 16-20% and ultimate bending strength increased by 45-57% against those calculated as PCaPC beam. On the basis of test results, a calculation method to estimate moment-deflection curve was proposed.
Some illogical statements and improper analyses in the above paper for the size effect on brittle fracture in steel are pointed out referring to related research papers published in the past. In particular, the fracture pattern of the employed small-scale specimens is incompatible with the actual pattern observed in real-scale members in steel building structures.