A Report On The Axial Stress Strain Behavior

ACI 318-63 requires that the minimum ratio of longitudinal bars shall be at least 1.0%. Also, The vertical center-to-center spacing of the lateral ties shall be one of the smallest of: (1) 16 longitudinal bar diameters to restrain longitudinal bars from buckling, (2) 48 tie diameters to ensure sufficient tie area to restrain the lateral displacement of the reinforcing bars, and (3) the least lateral dimension of the column to develop the maximum strength of the concrete core. As shown in Fig. 1, The dimensions and steel reinforcement details of the columns involved in this experimental program were particularly selected to represent relatively older columns. In this experimental program, the longitudinal reinforcement ratio, ρl, was constant

As the human body ages, it becomes more fragile. America’s infrastructure is nearly the same. With the everyday use of many large structures, such as bridges, buildings, and other large structures made of concrete and/or steel, many are beginning to wither away while the average American is unaware of these changes. In many projects around the world, there is a material that is being commonly used to strengthen structures known as Carbon Fibre Reinforced Polymer (CFRP). The types of structures that this material can help to strengthen includes, but is not limited to, reinforced concrete columns, bridge girders, steel structures, and cable

In order to create a column-free space, designers and engineers opted to use free spanning composite glue-laminated (glulam) wood-steel arches supported by inclined concrete buttresses (Chodikoff, 2009). For the arches, the glulam slabs were made from engineered timbers consisting of wood laminations bonded together with strong, waterproof adhesives, resulting in a structural component as strong as steel. To increase the lateral stiffness, and assist in carrying the bending stresses from unbalanced snow loading, each arch has steel components anchoring the glulam slabs – resulting in a composite glulam wood-steel arch (Gregory, 2010). The use of glulam for the arches allowed for the roof’s large 100-metre span and curved element to be produced (Dietsch, 2011).

References: 1, Carper et al., 2002; 2, Bloss and Courchesne, 2007; 3, Kates et al., 2004; 4, Palmen et al., 2005; 5, Hazlett et al., 2005.

(2003); Ford et al. (2003); Kubo et al. (2000); Vedam et al. (2001); Mageras et al. (2001);

Nakano et al., 2003; Tadagaki et al., 2005; de Munnik et al., 2015; Montaner et al., 2013

The experimental program was included testing of lightweight concrete specimens under concentric axial load in both tension and compression, to obtain the actual stress-strain properties of the produced FBLWC. The concrete mix using foam balls previously designed at Ain Shams University were used. Different specimens' shapes like prisms, cylinders and cubes were tested to obtain the mechanical properties such as compressive strength, young modulus, tensile strength and flexural strength.

But more than 80 developing countries in the world suffer from housing shortages resulting from population growth, internal migration etc. Most of the dwellings in rural areas are made of cheap local materials which are temporary and unsafe. Ferrocement is such a material that is slim and slender but at the same time strong and elegant which provides a potential solution to roofing problems [8]. The addition of fibers to the concrete enhances the strength properties of the composite and transforms the brittle cement composite into more isotropic and ductile material called FRC. But these two materials have some drawbacks. These two materials cannot be employed where high vibration, high tensile forces and high impact are to be resisted. Hence the solution lies in the new composite called fibrous ferrocement, which is the result of combining FRC and ferrocement. Fibrous ferrocement can overcome the limitations of both ferrocement and FRC to certain extent. Hence fibrous ferrocement can be employed where high impact, high vibration and high wear and tear are familiar [5]. In this unique material the advantages of both FRC and ferrocement are united. In fibrous ferrocement three types of reinforcement are used. The first type of reinforcement is welded mesh where smaller diameter bars are kept closely in both directions and are spot-welded. This mesh gives stability and shape to the structure. The second type of reinforcement

Fly ash offers both environmental advantages and also improves the performance and quality of concrete. It affects the plastic properties of concrete by improving workability, reducing water demand, segregation and bleeding and lowers heat of hydration increases the strength, reduces permeability, reduces the corrosion of steel, increases sulphate resistance, and reduces alkali aggregate reaction. It reaches its maximum strength more slowly than concrete made with the port land cement. Also, Concrete is a relatively brittle material, when subjected to normal stresses and impact loads. The tensile strength of concrete is less due to widening of micro-cracks existing in concrete subjected to tensile stress. Due to presence of fiber, the micro-cracks are arrested. The introduction of fibers is generally taken as a solution to develop concrete in view of enhancing its flexural and tensile strength. Fiber reinforced concrete is a short discrete, uniformly dispersed and randomly oriented suitable fibrous material used to increase structural integrity. The amount of fibers added to concrete mix is measured as percentage of the total volume of composites. Aspect ratio (l/d) is calculated by dividing fiber length (l) by its diameter

On comparing to a reinforced concrete component, an element made of high strength concrete will have minor deflection, slighter camber change, lower pre-stress loss and longer life relatively. Additionally, it gives heightened shear capacity of columns and stronger beam-column joints. The other characteristics of high strength concrete are higher compressive strength, better tensile strength and improved

This resulted in the formation of longitudinal cracks above the voids due to the large concentrated post-tensioning forces near the abutments, which created transverse splitting stresses, and due to the restraint of transverse concrete shrinkage imposed by the steel void forms. To solve this cracking problem, MTO recommended the addition of transverse prestressing to prevent shrinkage cracking and a decrease in span-to-depth ratio in 1975 in order to reduce the required prestressing force, which eventually led to the current maximum span-to-depth ratio limit of 28 (Scollard and Barlett 2004). As a result, in this study, 6 out of the 9 bridges built after 1975 have span-to-depth ratios below 28; the remaining 3 bridges are pedestrian bridges or European bridges.

The description of stress-strain behavior is similar to metals, but the mechanical properties of polymers depend on the strain rate, temperature, and environmental conditions.

This paper presents the results of an experimental investigation into the seismic performance of a composite moment resisting frame system that consists of reinforced concrete columns (with an embedded steel shape for erection purposes) and composite steel beam-reinforced concrete slab sections. Quasi-static reversed cyclic loading was performed on six two-thirds-scale sub assemblage specimens. Various detailing options were evaluated to provide full moment connection in both orthogonal framing directions at the beam-column joints. With appropriate joint detailing, specimens exhibited a desirable beam plastic hinge mechanism with stable hysteretic response. Composite beam sections maintained near full composite behavior beyond code baseddrift limits with good energy dissipation characteristics and were able to undergo large plastic rotation magnitudes. This framing system may represent a viable alternative for low-to-mid-rise structures in high seismic risk zones.

Nipun Verma et.al 2014, presented the Self-compacting concrete is gaining attention worldwide owing to its ability to compact without the need for either internal or external vibration even in areas of highly congested reinforcement such as beam-column joints. Since last two decades, several researches have been conducted on Self-compacting concrete and now application of SCC has gained momentum. In the present study, bond stress corresponding to the maximum pull-out load that can be regarded as the bond strength or ultimate bond strength was conducted. The slow development of compressive strength and bond strength in SCC at early age is generally due to

COMPARISON OF FLEXURAL STRENGTH VALUES OF PALM KERNEL SHELL CONCRETE MEASURED BY DIRECT AND INDIRECT METHODS