Mesoscale Analysis of RC Anchorage Performance in Multidirectional Reinforcement Using a Three-Dimensional Discrete Model
Mesoscale Analysis of RC Anchorage Performance in Multidirectional Reinforcement Using a Three-Dimensional Discrete Model
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DOI：
10.1061/(asce)st.1943-541x.0001780
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发表时间：
2017-07-01
影响因子：
4.1
通讯作者：
Eddy, Liyanto
中科院分区：
文献类型：
--
作者：
Hayashi, Daisuke;Nagai, Kohei;Eddy, Liyanto
为了研究锚固性能在多方向排列的钢筋，模拟进行了使用三维离散模型，特别是三维刚体弹簧模型（3D RBSM）。在3D RBSM中，材料被划分为通过离散弹簧沿其接触边界沿着互连的刚性体的集合。在这项研究中，例如，钢筋混凝土被网格化为1-2厘米的大小的刚体，其中打开，关闭，和滑动的裂缝可以通过变形或传递的两个刚体之间的内力通过使用沿着其接触边界的非线性弹簧来模拟。进行了模拟，一个作为参数的横向钢筋的数量和另一个不同的柱钢筋和嵌入式钢筋之间的净间距在拥挤的关节。这些模拟的结果进行评估，通过与实验数据比较，良好的协议，观察到的锚固能力，裂纹图案，和故障模式。模拟结果表明，如果柱钢筋和嵌入钢筋之间的钢筋间距非常接近，由于混凝土的非均匀行为，在以前的实验中观察到钢筋周围的大空隙，混凝土强度降低。模拟还表明，局部裂纹的扩展取决于钢筋的布置。这项研究表明，如何使用三维RBSM的细观分析可以是一个有用的技术来考虑钢筋的多方向布置的效果，导致在一个复杂的应力和应变状态，由于三维键转移机制。它可用于设计规范未涉及的拥挤区域的钢筋布置设计。因此，可以根据具体情况设计合理的钢筋布置。(C)2017年美国土木工程师协会。
To investigate anchorage performance in a multidirectional arrangement of reinforcement bars, simulations are carried out using a three-dimensional discrete model, specifically the three-dimensional rigid-body-spring model (3D RBSM). In 3D RBSM, a material is partitioned into an assemblage of rigid bodies interconnected along their contact boundaries through discrete springs. In this study, for example, RC is meshed into rigid bodies with a size of 1-2 cm, where the opening, closing, and sliding of cracks can be modeled by the deformation or transmission of internal forces between two rigid bodies through the use of nonlinear springs along their contact boundaries. Simulations are conducted, one with the number of transverse reinforcement bars as a parameter and another varying the clear space between column reinforcement and embedded reinforcement in a congested joint. The results of these simulations are evaluated through comparison with experimental data; good agreement is observed with respect to anchorage capacity, crack pattern, and failure mode. The simulation results indicate the concrete strength is reduced if the reinforcement spacing between the column reinforcement and the embedded reinforcement is very close because of a nonhomogeneous behavior of concrete, where in the previous experiment large voids around reinforcing bars were observed. Simulations also suggest that the propagation of local cracks depends on the arrangement of reinforcing bars. This research shows how mesoscale analysis using the 3D RBSM can be a useful technique to consider the effect of a multidirectional arrangement of reinforcing steel that results in a complex stress and strain state due to the 3D bond transfer mechanism. It can be used for the design of a reinforcement arrangement in congested areas that is not addressed by the design code. As a result, a rational reinforcement arrangement can be designed on a case-by-case basis. (C) 2017 American Society of Civil Engineers.