There are many types of concrete available to us, created by varying the proportions of the main ingredients. Several materials are used to produce a good quality concrete. They are all important because they impart strength and durability to the concrete. Proportioning a concrete mix for a given purpose is thus the art of obtaining a suitable ratio of the various ingredients of concrete with the required properties at the lowest cost. Poor compaction and improper curing will lead to porous concrete with low strength and high permeability.
The load exerted on the beams will be caused by; the load from the self weight caused by the deck, loads resulted to by the live loads, weight exerted due to car skidding as well as effect of braking and horizontal loads as a result of temperature and movements such as wind. Due to this reason, the beam should be strong enough to carry the load. The design shape of the beam will be as shown below. There are a number of forces that will act on the beams and the bridge thus the beams should be constructed in a way they will be able to
A complex structure required details planning and often a more intricate combination of trusses, comprised of multiple units being used at once. The combination of planar and space trusses that are made from metal can be discover in the construction of bridges and towers. Furthermore, a more details aspects of truss engineering involve the design of multiple trusses that are interwoven in a particular shape or for a specific purpose. Basically, the more complex the truss design, the stronger the structure will be. This is crucial for the tops of skyscrapers and other tall buildings because they must withstand a stronger wind resistance than structure that are lower to the
Concrete on the other hand works well in compression. In a composite section steel and concrete work complementary to each other to fulfil each drawbacks of the other. Composite buildings are preferred for their ease of construction and functionality. A composite building could be used in various forms. The construction could be consisting of a concrete slab with steel frames, or a composite frame wherein the frame consists of steel elements encased in concrete.
A combination of high tensile steel and mild steel reinforcement is used. The high tensile steel is usually positioned at the bottom of the concrete floor to withstand any tensile forces. The main reinforcement usually consists of 12mm diameter high tensile steel rod spaced from 150 to 225mm apart, and
Pushover tests were conducted on scaled models of ductile unit frames, directly braced by X and Knee steel braces. To design the X bracing and knee-bracing systems, the excess seismic load on each frame, due to the increased elastic stiffness of the combined RC frame and bracing system, was determined and the relevant braces were designed for these excess loads. Test outcomes indicate that the yield capacity and the strength capacity of a ductile RC frame could be increased and its global displacements could be decreased to the desired levels by directly adding either an X bracing or a knee-bracing system to the frame. Steel X bracing could provide a stiffer bracing system but reduces the ductility of the ductile frame. Knee bracing could be employed to provide the desired ductility level for a ductile design.
20 Points zero tolerance Quality Control measures Unlike other construction materials (i.e. steel, cement and admixtures) which are manufactured at factories in the controlled condition, the concrete is produced at site or OMC plant where the conditions may not be favorable every time. Also, the concrete is prepared by mixing of fine aggregates, coarse aggregates, cement, admixtures and water. The source of these materials, hence their properties, change very frequently which in turn effect the quality of the produced concrete. All the structures are designed assuming a standard grade of concrete, thereby assuming certain minimum values of its strength and other physical parameters.
Concrete gravity consisted of solid concrete and adequate stone masonry. By constructing this dam, the self weigh of the dam is used to resist huge volume of water. However, it should be noted that the height and the scale of the dam depends on the foundation. The load can increase with a stronger foundation. The removal of the deposits in the water should also be removed regularly to protect the dam from erosion.
From a strength perspective (ultimate tensile strength of 880 MPa or 90 kg/mm2), the C– Mn rail is popularly known as90 UTS rail or Grade 880 rail. The pre-reinforced concrete sleeper is the second component of the rail track. The entire track structure is more stable due to the heavier weight of concrete sleepers5. A grooved rubber pad (made of styrene butadiene, poly butadiene rubber or natural rubber) is placed between the rail and the sleeper. This absorbs vibrations and impact, provides insulation and also increases the coefficient of friction between the sleeper and the rail6.