Educational Video: Shear and Torsion

I found series of videos on youtube.com illustrating the concept of shear and torsion affecting the structures during the earthquake. The instructors are from U of Illinois and supported by NSF and NEES (www.nees.org). In the video, the instructors deliver the complex concepts of shear and torsion in very simple way so that the audiences can understand the concepts very easily. Let's watch the videos below:

  

Introduction

Shear Effect

                                                         Torsion Effect

Combined Responses

FEA of Concrete Structures

It is well-known that reinforced concrete (RC) is one of the important building materials due to its constructibility, economy, and efficiency of the material. Structures properly designed and constructed using RC are acceptable for its stiffness and strength. In general, the designers design all RC structures to satisfy the following things:i) the structure must be strong and safe, ii)the structure must be stiff and appear unblemished, and iii)The structure must be economic.

To satisfy the above goal, advanced analytical tools are indispensable for assessing the performance of the structures(e.g. cracking and deflection under service loads, ultimate load, failure mode and pattern, and load-deformation of structures) constructed using reinforced concrete which is naturally non-linear subjected to external excitations. The nonlinearities are due to a composite materials made up of concrete and reinforcement, nonlinear behavior of concrete itself, and the interaction between reinforcing steel and concrete though bond-slip, aggregate interlocking, and dowel action at the interface of both materials. In addition, the real world structures are usually in the forms of complex in shape and functions; for examples, high rise building, nuclear power plants, bridges, off-shore platforms, and underground structures. These structures thus requires advanced and sophisticated analytical tools. The current tools that implement analytical and numerical methods in assessing the performance of concrete structures are practically adopted the so called Finite Element Analysis "FEA". The development of FEA for concrete structures is very interesting with a long history since 1967 and the next post I will introduce some here.