讲座嘉宾：Dr Samir Dirar
英国伯明翰大学结构工程系
邀请人：杨健 土木工程系
讲座时间：12月11日（周五）13:30-16:00
讲座地点：木兰船建楼 A1008室
主讲嘉宾介绍：
Dr Samir Dirar现为英国伯明翰大学结构工程系讲师，博士毕业于剑桥大学。Dr Samir Dirar在可再生混凝土、结构健康监测、FRP在混凝土结构中的加固补强、预应力混凝土构件、混凝土结构的新型数值解法以及非结构构件抗震性能等领域内取得了多项创新性成果，在国际权威学术期刊发表论文30余篇。Dr Samir Dirar也主持了英国工程和自然科学研究委员会（EPSRC）、英国结构工程师协会（IStructE）等知名机构的纵向课题10余项目。
讲座摘要：
The lifetime extension of existing reinforced concrete (RC) infrastructure is an application of considerable economic importance. It has been estimated that the cost of replacing structurally deficient bridges in Europe, a significant amount of which are RC bridges, is about €400 billion. In the United States, one in nine of the 607,380 bridges have been rated as structurally deficient and $20.5 billion would need to be invested annually to eliminate the bridge deficient backlog by 2028. This relatively high investment is partially attributed to the fact that the traditional methods of repair are labour intensive and/or time consuming. Therefore, the development of more efficient, reliable, and cost effective strengthening techniques is of great importance.
The deep embedment (DE) technique is a promising shear strengthening method for existing concrete structures. In this method, fibre reinforced polymer (FRP) or steel bars are embedded, using epoxy resin, into holes drilled in the shear spans of existing concrete structures.Unlike the externally bonded (EB) and near-surface mounted (NSM) techniques, the DE technique relies on the concrete core to transfer stresses between the concrete and FRP bars. The concrete core provides better confinement and consequently better bond performance to overcome the debonding failure usually associated with the EB and NSM FRP strengthening methods.
This talk will highlight preliminary results of an ongoing experimental program on DE strengthening of full-scale shear-deficient RC beams. It will also present a three-dimensional nonlinear finite element (FE) model capable of predicting the overall behaviour of RC beams strengthened in shear with DE FRP bars. The predictions of the FE model were validated against experimental results from the published literature. The FE model was then used to carry out parametric studies to examine the effect of FRP bar orientation, concrete compressive strength, shear span-to-effective depth (a/d) ratio, size effect, and interaction between the DE FRP bars and steel stirrups on the predicted shear strength. Furthermore, the accuracy of the prediction of the FRP contribution in the Concrete Society TR55 (Concrete Society 2012) design guidance is evaluated.
