Kenichi Matsuoka

Impact behavior of shear-failure-type RC beams without shear rebar

In this study, to establish a rational impact-resistant design procedure of shear-failure-type reinforced concrete (RC) beams, falling-weight impact tests were conducted. Twenty-seven simply supported rectangular RC beams without shear rebar were used. All RC beams were of 150 mm width and 250 mm depth in cross section, with rebar and shear-span ratios taken as variables. An impact load was applied at the mid-span of the RC beam by dropping a free-falling 300 kg steel weight. In these experiments, the impact force excited in the steel weight, the reaction force, and the mid-span displacement were measured and recorded by wide-band analog data recorders. After testing, crack patterns developed on the side-surfaces of the RC beams were sketched. The results obtained are as follows: (1) the shape of the hysteretic loop between the reaction force and the mid-span displacement can be assumed to be triangular when the RC beam collapses due to severe diagonal cracks developed from the loading point to the support points; (2) shear-failure-type RC beams without shear rebar under impact load can be designed with a certain safety margin by assuming a dynamic response ratio of 1.5 and an absorbed input energy ratio of 0.6; (3) the required static shear capacity for RC beams against impact load can be evaluated by a proposed simple equation.

Analysis program for the design of flexibly jointed frames

Abstract To estimate second-order effects on the behavior and strength of steel frames with semi-rigid connections, as well as to perform practical frame design easily and rationally, an attempt was made to develop a structural analysis program considering the characteristics of semi-rigid connections in a direct manner. The program was developed with the following three main routines: 1. 1. The practical procedure for structural analysis is based on a simplified method presented previously. This method uses the closed-form elastic solutions of beam-columns and takes into account the inelastic property of connections. 2. 2. The program PACOM (Parameter Analysis of Connection Models) prepares the parameters of semi-rigid connection models using the program SCDB (Steel Connection Data Bank). 3. 3. The graphic routine draws the general configuration and sectional force diagrams of the overall structure, the hysteresis loop in relation to the connection moment and relative rotation. The development of this system was made on an engineering workstation with a drawing function on a CRT display.

STATIC ANALYSIS OF A CONTINUOUS UNDERGROUND DEEP WALL UNDER CONSTRUCTION OF THE MAIN TOWER FOUNDATION OF HAKUCHO OHASHI

白鳥大橋主塔基礎の建設には, 海中に構築された人工島を利用して大深度地中連続壁工法が採用された. 本論文は, この工法を対象として基礎施工時の大深度地中連続壁構造の静力学的挙動を軸対称アイソパラメトリック四辺形リング要素を用いた三次元構造解析により明らかにしようとするものである. また, 合わせて施工時に計測された各種実測値との比較検討を行い, 本解析法の妥当性の検討を行った. その結果, 本解析法により得られた結果は, 実測値と比較的良い一致を示し, 本解析法がこの種の構造解析に有効であることが明らかとなった.