Hisahiro Hiraishi

SEISMIC PERFORMANCE OF REINFORCED CONCRETE BUILDINGS DESIGNED BY CURRENT SEISMIC CODE IN METROPOLITAN AREA

This paper conducted earthquake response analysis of reinforced concrete buildings designed by Lateral Load Carrying Capacity provided by current code considering the precise site amplification effect. The total number of site was 118 in Metropolitan area. The paper also discussed the seismic performance of buildings systematically from the viewpoint of site class, structural characteristic factor, height of buildings, etc... based on the analytical results. Finally, the paper concluded that the seismic performance of the buildings greatly differ for each site, and presented the map which showed the ratio of the response drift angle to the limit drift angle for each site.

STUDY ON INFLUENCE OF THE VERTICAL DISPLACEMENT OF PILES ON RESPONSE OF SUPERSTRUCTURES

The conventional seismic design of buildings with the pile foundation often uses the fix foundation model. However, in actual buildings with the pile foundation, sway and rocking occur in the span direction, which have a significant influence on the seismic performance. The purpose of this study is to investigate the effect of the vertical displacement of the piles on the response of superstructures. The paper showed that the base shear of the superstructures given by the soil-pile-structure interaction model was remarkably small compared with the fix foundation model, and that the tendency of a top heavy shape of the shear coefficient distribution along the height was significantly alleviated if the vertical displacement of the piles was taking into account.

EVALUATION METHOD OF SLIP PHENOMENA FOR SHEAR WALLS WITH HING ISOLATED STRUCTURAL SYSTEM

The test results of the hinge isolated shear walls (called as HISS RC walls) showed slip phenomena at the wall in the large deformation range after flexural yielding. If their slip phenomena had been restricted, they, obviously, could have had stable energy absorption capacity. This paper reports the details of slip phenomena in terms of load-displacement relationships and vertical displacements at the wall bottom. Considering dowel behavior, the slip stiffness at the load zero can be modeled using pile registration formulae. The ratio of the flexural stiffness to the slip stiffness is an effective index to assess the effect of slip phenomena after flexural yielding on energy absorption characteristics.

STUDY ON EARTHQUAKE RESPONSE OF BUILDINGS CONSIDERING SITE AMPLIFICATION EFFECT

In this paper, the equations to calculate the seismic response of buildings considering precise effect of the soil at the building site are presented. These equations are readily used for the seismic design of buildings. Based on the equations, effect of the strength of building and soil on seismic response was discussed. It is found that seismic responses, particularly those of the buildings with short or long natural periods significantly differ depending on accuracy of soil amplification. Finally, the availability of this calculation method is confirmed by time-history seismic response analysis.