| 種別 | paper |
| 主題 | Plastic-Fracture Stress Transfer Model for Concrete Discontinuities |
| 副題 | |
| 筆頭著者 | Zhishen WU（Nagoya University） |
| 連名者1 | Ahmed M. FARAHAT（Graduate School of Nagoya University） |
| 連名者2 | Tada-aki TANABE（Nagoya University） |
| 連名者3 | |
| 連名者4 | |
| 連名者5 | |
| キーワード | |
| 巻 | 14 |
| 号 | 2 |
| 先頭ページ | 1047 |
| 末尾ページ | 1052 |
| 年度 | 1992 |
| 要旨 | INTRODUCTION The use of non-linear mathematical models for the behavior of concrete structure is becoming increasingly popular. The results obtained using these models, however, will be accurate only if realistic inaterial properties and adequate mechanism are incorporated. Also, the models of general use are necessary to be amenable to the implementation in the numerical procedure such as the finite element method. For these reasons, one of the components in the behavior of concrete structures which could not be satisfactor described up to now is the mechanism of shear transfer across the cracks. Although a great number of macroscopic models have been constructed to deal with the shear transfer problem, none of those models can clearly express the detailed distribution of stresses across the crack. Although some theoretical models have been also proposed, none of those models can deal with the problem to consider the detailed mechanism and surface degradation of contact until crushing at the contact zone. In the present study, a new motivated constitutive law for the behavior of concrete discontinuities with contact surface degradation and material nonlinearity is presented. Both plastic and fracture deformations with the accumulated damage are formulated at the microlevel. By paying attention to the detailed contact mechanisms both for the contact between mortar and mortar and that between aggregate and mortar, the total deformation are assumed to be due to the aggregate interlock and the degradation of mortar surface. The degradation of mortar surface is expressed by the degradation of the original asperity angle due to the current accumulated damage. Moreover, to simulate all sorts of the nonlinearities, Mohr - Coulomb yield surface in stress space is modified. This modification contains the moving of the subsequent yield surface due to the variation of cohesion, internal angle of friction, and tensile strength because of the accumulated damage. The proposed model showed its capability to predict the experimental data. CONCLUSIONS A general constitutive law for shear stress transfer problem is proposed. A major feature of the proposed model is the development of an explicit relation between the increments of stresses and relative discontinuity displacements at all possible interfaces across the crack. Such a relation can be implemented in FEM computer codes and should render more realistic and reliable than those currently performed with more simple idealization. The numerical calculations showed that the proposed model can predict the shear transfer problem for concrete discontinuities. However, it is considered that the present model has its great advantage to deal with more general problems such as the effect of dilatancy, the cyclic behavior and the time effect. These phenomena are under investigation now. |
| PDFファイル名 | 014-01-2181.pdf |