Advantages Of Prestressed Concrete

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

A post tensioned slab is a slab of concrete which has been pre stressed a certain way to increase the strength of the concrete. Before pouring a post tensioned slab, steel strands or cables are placed to strengthen the slab and give it support.

When designing a building, the load that must be supported is a very important consideration. Various building materials will each have their own levels of strength and ability to support loads. In addition to this, the way in which the building material is utilized may also play a role in the ability of the building to support large loads. The implementation of concrete as a building material led to much stronger walls and supports in Roman buildings. Additionally, the development of the arch was revolutionary in its ability to support loads. The types and sizes of structures that the Romans could build became unlike anything seen before, and they also became very interested in working with interior spaces, as well (Ambler, n.d.).

When an arch is seen in the building, it is often seen as a design to beautify a house in this part of the world, but it functions more than just a design, it perform more important role than just a design. Indeed, it beautifies but according to Romans, it is also a supporting structure that makes the house very strong, there is no need to ague this because it is a known fact world wild. The reason why Roman concrete was seen as one of the strongest because it contains volcanic lava ashes, which is a component in cement making that makes the concrete very strong. The focus of this writing will be on development and important of both concrete and arch.

Every construction material and system has its own characteristics which to a greater or lesser extend influence the layout, span length, construction depth, stability system, etc. This is also the case for precast concrete, not only in comparison to steel, wood and masonry structures, but also with respect to cast in-situ concrete. Theoretically, all joints between the precast units could be made in such a way

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.

This is the most recent type of concrete formwork. It’s an emerging tech for RCC construction as well as architectural design work. This materials’ flexibility creates the ability to make concrete of any shape.

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

It is well-known that many reinforced concrete columns including particularly those RC columns constructed prior to the 1970s have been reinforced with an inadequate amount of transverse steel reinforcement which provides inefficient confinement to the concrete core or lateral restrain to the longitudinal reinforcing bars. Since the FRP composites owe some of the extraordinary properties such as high strength-to-weight ratio and excellent corrosion resistance, the use of externally bonded FRP composites has significantly increased in the construction industry. As confinement jackets, using FRP techniques is nowadays become one of the most popularly innovative confining means for upgrading existing RC structures. Therefore, several experimental studies have been carried out to date, such as on retrofitting or strengthening those structures with FRP systems, for example. In case of rarely sever seismic loads, establishing an axial stress-strain model considering cyclic axial compressive load is, in turn, imperative for simulating FRP-confined RC columns subjected to earthquake loads and performing a proper seismic design of such FRP-jacketed RC Columns, which are typically subjected to both axial and lateral force Wang et al.(2012). A uniaxial stress-strain model can be developed from laboratory testing results on axially loaded concrete columns confined with fiber-reinforcement polymer (FRP) composites and can then be applied as the constitutive law for confined concrete

In February 2007, an adult male construction worker sustained fatal injuries after he fell three floors following the collapse of the precast concrete floor slabs. The precast concrete slabs were fabricated off site and then transported to the construction site. These concrete floor slabs weighed approximately 7 tons and were positioned on the buildings steel structure frame that was composed of vertical and horizontal steel columns and beams. Once the slabs were positioned, the workers were supposed to have permanently secured them to the steel frame of the building using grout or welding. Before this

Over the past quarter century, many of both the experimental and analytical studies have increased dramatically on the monotonic behavior of FRP-confined concrete columns, and as a result, many axial stress-strain models have been proposed; however, most of them have focused largely on FRP-confined plain concrete cylinders numerous people tested (e.g., Mirmiran and Shahawy 1997; Mirmiran et al.1998; Xiao and Wu 2000; Lam and Teng 2002, 2003; Berthet et al.2005; Almusallam 2007; Benzaid et al.2008; Eid and Paultre 2007, 2008; Teng et al.2009; Smith et al. 2010; Cui et al.2010). A certain number of these researches have included non-circular unreinforced (plain) columns (e.g., Rochette and Labossiere 2000; Ilki and Kumbasar 2002; Youssef 2003; Rousakis et al.2007; Youssef et al. 2007; Benzaid et al.2008; Wu and Wei 2010; Wu and Zhou 2010; Benzaid and Mesbah 2013). Owing to the limited progress of the experimental investigations carried out on FRP-confined non-circular reinforced concrete columns (RC) tested under cyclic axial compression loading, a well-defined study indicates that a few essential gaps need more further research. As a result, the current study aims to consider the most significant issues, namely, the influence of 1) cross-sectional aspect ratio, 2) internal hoop or longitudinal steel reinforcement ratio, and 3) cyclic or monotonic compression loading pattern. These issues which form the basis of the experimental program on CFRP-confined rectangular reinforced

Two papers to study the behavior of partially prestressed continuous composite beams consisting of a concrete slab supported by a steel beam were presented by Basu et al. (1987) [7, 8]. In these researches, the prestress was introduced in the negative moment regions only . The first paper presented analytical study on the effect of prestressed on crack prevention in the negative moment region and savings in material due to superior structural action. It was concluded that partial prestressing increased the load capacity of the beam by about 20% and eliminated the problem of concrete deck cracking in the negative moment region. It was also concluded that the deflection of the prestressed beam is about thirty percent less than that of the non-prestressed beam. The results of tests on a model of continuous

This is a precast and prestressed concrete elements with continuous voids to reduce the self-weight. They are immensely used as roof o floor deck systems. They are used as spandrel members, bridge deck and wall panels units. Slabs are

The maintenance, restoration and development of structural components, is maybe one of the most typical problems in construction field applications. In addition, a huge number of structures developed in the past utilizing the ancient established design codes in various parts of the world are basically structurally hazardous as indicated to the recent time design codes on the other hand the retrofitting has become necessary due to the environmental degradation, heavier loading conditions and their life spans. Therefore, various strengthening techniques are being introduced, historically the structural components were repaired by post-tensioning or jacketing with new concrete in conjunction with a surface adhesive, since mid-1960’s steel

|Design is based on load distributing characteristics of the |Design is based on flexural strength or slab action |