Yusuke Kurihashi

Numerical Simulation of Impact Response Behavior of Rectangular Reinforced Concrete Slabs under Falling-Weight Impact Loading

A numerical analysis method for rectangular reinforced concrete slabs under falling-weight impact loading is established. The proposed method using finite element analysis incor-porates a simple constitutive model for concrete elements. The applicability was investigatedcomparing the numerical results with the experimental data. Falling-weight impact tests wereconducted on reinforced concrete slabs with different supporting conditions. These were: a slabwith line supports on four sides; a slab with two line supports on two opposite sides (the othertwo sides were free); and a slab with one line and two corner-point supports. Following resultswere obtained from this study: (1) the time histories of dynamic responses are well predictedby using proposed numerical analysis method; (2) maximum reaction forces and the maximumdeflections in the slab center below the loading point, and characteristics of the damped freevibration after falling weight was rebounded, can be better predicted; and (3) major crackpatterns can be roughly predicted despite of support conditions.

Load-Carrying Capacity of Flexural Reinforced PC Beams with Pretensioned AFRP Sheet

To develop a rational flexural reinforcing method for prestressed concrete (PC) beams with pretensioned Aramid Fiber Reinforced Polymer sheet (AFRPs), the new anchoring method is proposed. It is the concept of this method to rationally disperse the concentrated anchoring stress due to bonding the cross-directional AFRPs in the anchorage areas and to gradually relax the high strain caused at the ends of sheet due to applying the high-strain type epoxy-resin in the areas. Its applicability was confirmed by conducting static four-point loading test of the PC beams reinforced by means of the proposed method. From this study, following results were obtained: 1) applying the proposed anchoring method, predetermined pretensioning force of the sheet can be perfectly introduced into the beams without any mechanical anchoring devices; 2) the cracking and yielding loads, and the ultimate load of the PC beams can be upgraded due to bonding pretensioned AFRPs.

Dynamic Response Analysis for Rigid Steel Portal Frames under Impact Loading

In order to improve our basic understanding of the impact-resistant behavior of steelstructures, three-dimensional elasto-plastic FE analysis was conducted for steel portal framesunder impact loading. Here, two rigid portal frames of different column size were numericallyanalyzed taking the impact velocity of the falling weight as variable. The results obtained fromthis study are as follows: 1) maximum displacement of the frame increases linearly with eachincrement of the input impact energy; and 2) the bending moment distribution of the wholeframe at the time when the maximum response displacement occurs is similar to that understatic loading.