Journal of Civil Engineering Researchers
Volume:1 Issue: 3, 2017

Progressivecollapse of buildings is generally begunby a local failure due to unexpectedactions continuedby subsequent chain effect of the structures which may result in extendedrange failure or even collapse of the entire buildings. Progressive collapse of building structures has been widely studied by designersand researchers last years. This paper assessesand comparesthe current researches on this objectfrom experimental study,numerical simulation and theoretical analysis. Given the limitation of costs and problemsof experimental tests, the experimental studies investigate the collapse mechanism suchas development of stresses and strains of materialsand also damage to failure extending of themmainly via the scaled down samples of structural constituentsand substructures. On the other hand, the collapse behavior of entire building structuresis analyzed via the numerical proceduressuch as the finite element method. Furthermore the collapse resistance demand and the stabilityassessment for building structures are theoretically studied in depth at simplifiedtheoretical models.

Concrete is one of the most widely used materials in the world. Considering the need to build high-rise structures, especially in building industry, it is better to reduce the dead load of buildings, structures lighter and also reduce the stress of.One of the best solutions for this purpose is using lightweight aggregate concrete in addition to make structures has another benefit too.In this paper we show that lightweightconcreteespecially at elevated concrete structures can be a great alternative to Ordinary concrete. Lead only to reduce the dead load of the concrete structure does not havebut sound insulationand thermaland the ability to recycleand various other benefitsare the advantages of this type of concrete.The use of concrete in construction increase the cost of materials but overall, economic savings willbe greater in high-rise structures. The use of lightweight aggregate concrete not only in concrete but also has very efficient in building blocks. In this paper comparing the two types of concrete has been studied in two ways. First benefits of physical propertiesand second in terms of properties engineeringincluding compressive strengthtensile strength and modulus of elasticitybeen discussedand proven that the lightweight concrete has many advantages substitute for conventional concrete and old material

This studypresents a brief review of a significant research performed in the area of semi-active control systems which is a type of smart structures. The main focus of the review has been derived from journal articles which has been published from1997 to the present. This paper reviews articles on semi active control of structures which include magneto rheological(MR) fluid dampers, semi activestiffness dampers, semi-active tuned liquid column dampers, and piezoelectric dampers. A review of hybrid control systems and control strategies will be presented in the companion paper.

In order to understand further the influence of using the concrete-filled steel tube (CFST) composite beams in the modern structural projects, the flexural and energy absorption capacities of simply supported rectangular hollow steel tube (HST) beams filled with normal concrete was investigated in this study. Eight downscale specimens (HST and CFST beams) were tested experimentally under static four-point bending, where these beams have varied tube section classifications (Class 1 and 3) and lengths. Generally, the results confirmed that both of the moment and the energy absorption capacities of hollow steeltube beams were significantly improved when filledwith concrete, specifically for those with section Class 3. However, this improvement ratio reduced gradually with increasing of tube’s thickness (Class 1) and/or beam’s length.