The term "fire safety engineering" refers to the process of applying scientific and engineering principles to the effects of fire in order to lessen the number of deaths and property damage caused by fire. This is done by determining the risks that are involved and providing the most effective method for implementing measures of prevention or protection. The paper showing experimental results of ordinary concrete columns made of "NSC" subjected to axial load and cyclic firing is presented in this study. the bearing capacity of the column decreased. all samples have been loading an eccentric load with "e = 75 mm" ,"e / h = 0.50," and the ratio Celsius (30%Pu) continuously through the burning period. The first column(C1) was the sample control with out exposure cyclic fire , and the second column was subjected to four burning cycles over the course of four days, with a duration specific of "45 minutes" for each cycle, at a temperature of "400 °C", and the third column was subjected to four burning cycles over the course of four days, with a duration longer amount of "75 minutes" for each cycle, at a temperature of "400 °C, ", the four column was subjected to four burning cycles over the course of an of four days, with a duration specific of "45 minutes" for each cycle, at a temperature of "600 °C " , the bearing capacity of the column decreased. that to be amount losses (C2,C3 and C4) comparison to (C1) equile ( 27.20 , 29.12, and 36.40)% respectively. the fracture load of the experimental columns varied by decreasing with these variables. Additionally, the depth and spread of the cracks increased with the increase in burning duration and target temperature.
Progressive collapse is a partial or total failure of a building that mostly occurs when the build-ing loses primary structural elements (typically columns) due to accidental or natural hazards. The failure of structures due to an earthquake is one of the most important and frequent types of progressive collapse. In this study, the finite element method is used to assess the response of multistory reinforced concrete buildings subjected to column loss during an earthquake. Three-dimensional nonlinear dynamic analyses are carried out using SAP2000 V.20 program. The ef-fects of different parameters on the progressive collapse behavior are investigated, namely: the location of the removed column within the ground floor; the method of column removal (sudden, in two-steps, and in four-steps) and the removal timing during the earthquake. It is demonstrated that the collapse occurs when all or most of the hinges at the bases of the ground floor columns reach their collapse level. The chosen column removal timing and policy affect the structural behavior considerably. It is realized that, the risk of building collapse increases when the removal timing harmonizes with the peak ground acceleration timing. Based on the adopted earthquake characteristics and building configurations, it is found that, the two steps removal scenario is the most dangerous one.Keywords:Progressive collapse, Concrete buildings, Seismic load, Nonlinear dynamic analysis, Plastic hinge.© 2014
Deep mixing technology is used to improve the engineering properties of soil. In this review, previous studies on the properties and problems of weak soils were collected and explained, focusing on silty soils found globally and locally. The study also includes a discussion of physical and chemical improvement methods, specifically (cement columns). The advantages of deep mixing technology are also covered from an engineering and economic point of view, as well as its relationship to the environmental impact, as it is one of the sustainable development techniques due to its use of environmentally friendly materials. In addition, one of the objectives of this research is to study the methods of adding cement, whether in the form of powder (dry method) or mortar (wet method). A comparison was made between them to clarify the advantages and disadvantages. It was found that what distinguishes the use of the dry method from the wet method is that the former is more common. The method's effectiveness depends on the soil's moisture content, so the technique is ineffective in soils with less than 30% water content. As cement hydration produces a cementitious gel (CSH) that binds soil particles together, leading to early strength gain, pozzolanic reactions cause increased shear strength and decreased soil compressibility. Finally, some recommendations are included in this article to understand the behavior of cement columns in improving soil and avoiding problems
The study of springs Abu-Aljeer natural asphalt at proven of al-anbar (Iraq), to find a mean of exploiting the asphalt springs as alternative energy resource, Included two stages The first: Separation the components of asphalt in two ways the first is column chromatography and second represented by extraction- chromatography. The results of separation were 10.20% Asphltene, 89.18% Maltene which separated lately to (Paraffinic 45.23%, Aromatic 28. 39% and Resin 21.66%). The second: Trying to improve the asphalt specifications by using natural materials that are available locally (limestone) with (5, 15, 25, 35%), which have given good results. Rheological properties have been tested, in such average that (virgin Softening was 430C, became 560C, Penetration was 110 dropped 39 and viscosity was 11355 turnedy other 47231cent-Stok, mm2Sec), and flash point ( 1790 C became 200 0C), Fractionated parts of asphalt were characterized by (UV), (FT-IR) spectra. This study also clarified paraffin compounds which represent the main part material and the colloidal state is in Gel phase.
The behaviour of high-strength fiber reinforced concrete columns was observed with a testing program of 7 columns, loaded eccentrically. The theory was analyzed by modifying the stress block diagram of concrete. The experimental results show that using high-strength fiber reinforced concrete with fiber volume fraction of 1.0%, increased the column ultimate capacity up to 40% in addition to increasing its ductility and toughness, significantly. The proposed theoretical analysis gave a good estimation of experimental results.