Determination of Pull Out Capacity of Steel Bar in Concrete

Steel frame structures are made as the name suggest from steel, the material is strong and flexible. When weight is added it bends without cracking. Another characteristic of steel is that its plasticity or ductility, meaning that when force is added it won’t crack however it will lose shape therefore giving warning for people to evacuate the building. A disadvantage of steel is that is loses strength when subject to fire. Studies have shown that it can loose up- to half its strength when subject to fire, therefore making it imperative to cover the steel with boards or spray on.

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

Concrete one of the most common and appropriate material in building a bridge. Concrete is strong in compression but weak in tension. However, concrete embedded with steel bars, known as reinforced concrete, serves as a solution for the steel carries all the tension. Less concrete will be used with reinforced concrete and the concrete that is used protects the steel from fire and corrosion.

Concrete is a tough and reliable material, and it can be used for a wide range of projects. Eventually though, a structure made from this versatile material will need to be replaced. At the very least, it may require repairs.

A concrete beam is prestressed by pulling on steel rods running through the beam and then anchoring the ends of the rods to the ends of the beam. This exerts a compressive force on the concrete, offsetting tensile forces that are exerted on the beam when a load is placed on it. (A weight pressing down on a horizontal beam tends to bend the beam downward in the middle, creating compressive forces along the top of the beam and tensile forces along the bottom of the beam.) Prestressing can be applied to a concrete beam that is precast at a factory, brought to the construction site, and lifted into place by a crane; or it can be applied to cast-in-place concrete that is poured in the beam's final location. Tension can be applied to the steel wires or rods before the concrete is poured (pretensioning), or the concrete can be poured around tubes containing un tensioned steel to which tension is applied after the concrete has hardened

Failure principles for retaining walls are similar to those for embankment when bearing capacity of the foundation is insufficient to carry the load pf soil block and facing wall failure will occur.

Arch bridges have incredible natural strength. Loads on these structures are carried outward along the curve of the arch to the supports, or abutments, at each end. Therefore, any and all loads from the bridge deck are diverted to the abutments and encounter a reactive force at the ground surface. This reactive force creates a resistance which travels upward through the arch and to the keystone in order to support the bridge deck load. Although these structures have been used throughout history, the more recent use of reinforced concrete and steel has increased the complexity of arch bridge construction. Arch bridges

The definition of high strength changes over the years as concrete strength used in the field increases. Any construction activity requires several materials such as concrete, steel, brick, stone, glass, clay, mud, wood, and so on. However, the cement concrete remains the main construction material used in construction industries. For its suitability and adaptability with respect to the changing environment, the concrete must be such that it can conserve resources, protect the environment, economize and lead to proper utilization of energy. To achieve this, major emphasis must be laid on the use of wastes and byproducts in cement and concrete used for new constructions. The utilization of recycled aggregate

Construction of steel bridges in the 19th - 20th century mostly depended on the use of rivets for connection. Bridges got built at a much greater rate than any other steel or iron construction using rivets. Riveting was a better-proven and understood method of construction. They made a very strong connection when applied but were very prone to corrosion through rusting. Existing historic steel bridges are aging and experiencing increased levels of deterioration due to increased demand in vehicle weight and traffic volume. These bridges are increasing becoming weaker as the rivets used in their contact wear out leading to instability and unreliable due to the poor construction. Assessment of old bridges for maintenance purposes occurs regularly. These bridges have to undergo regular maintenance and reinforcements. This aids in strengthening them and ensuring that they offer adequate and reliable service to the general public.

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

Galvanized corrugated steel sheets are placed above the bridge girders from flange to flange to act as a stay-in-place deck form. Furthermore, these steel deck forms act to provide support for the reinforcing steel in the deck slab as well as supporting the weight of weight concrete during the construction process. Corrugated steel stay-in-place deck forms remain in place for the live of the structure thus serving to eliminate the need of form stripping and the associated schedule time. Corrugated Steel Stay-in-Place Deck Forms can be used on steel and precast – prestressed

Abstract: Advancement in recent years on the efficiency of glass fiber-reinforced polymer (GFRP) in production and cost benefits have increased their use as alternative means to steel rebar in bridge deck bases. The purpose in applying rebar is to increase the tensile strength of concrete. Considering the versatility of bridges there are many factors that need to be analyzed when choosing whether to use steel rebar or GFRP material such as: cost, tensile strength, and weather resistance. Stress-strain graphs were calculated, graphed, and analyzed to determine the yield tensile strength and stiffness of steel rebar and GFRP. Data collected from alkaline bath tests were graphed and analyzed to determine the thermal and corrosion resistance of each material. Costs per square inch of each material were also compared as well as each materials quality and life expectancy. The results of the conducted test analysis found the GFRP to have greater thermal resistance, lower cost, and higher life expectancy than the steel rebar, however the steel rebar’s stiffness was found to be about six times larger than the GFRP’s. These results suggest that the advancements in GFRP can provide longer lasting bridge structures and will change the future of construction and restoration of bridges.

Abstract: This study aimed to compare the seismic behaviour of different bracing systems in 10th time smaller real prototype steel building model. The uniaxial shake table experiment was carried out to assess the structural performance on different bracing systems in same storey height building (model type-I) and different storey height building (model type- II). Three structural configurations were used: bare frames (BFs), X- braced frames (XBFs) and Diagonal braced frames (DBFs). The effects of some parameters influencing the seismic performance, including the type of the bracing system, the storey height of the were investigated. The results show that the different braced frames performed well in terms of joint displacement and performance point when compared to the simple bare frame frame in steel buildings. It can be concluded with a comparative account of the obtained results, that use of XBF and DBF enhances structural performances. DBF shows highly effective and economical because of it consume lesser material and give effective result.

Externally prestressed structures, initially developed for bridges, are now becoming popular in bridge construction and strengthening or rehabilitation of existing structures. Comparing with an internal prestressing system, an external prestressing system has some advantages, such as being simpler to construct and easier to inspect and maintain. Prestressed composite beams have been studied by several authors. In this chapter, a review of the research works carried out on external prestressed composite steel-concrete beam is presented.