Post-tensioned concrete construction in buildings has seen extraordinary growth all over the world since it was first introduced in the 1950’s. post-tensioned concrete is perhaps the most significant development in the design and construction of concrete buildings over the past century.
Our company is a pioneer in this field with experience in the construction of prestressed slabs in high-rise buildings (towers)
See below 5 benefits of using post-tensioning for building construction
1. Reduced overall cost
Post-tensioning saves construction costs in terms of concrete and reinforcing steel quantities when compared to conventional reinforced concrete construction. Further on it there is cascading cost savings that occur in many components of the total building cost as noted below:
a) Since PT floors are thinner, with limited or without beams, there is generally an overall savings of 20% in the dead load of the building compared to conventional concrete. Due to this decrease in dead load, the amount of reinforcing steel is reduced in columns and foundations.
b) Unlike conventional concrete slabs, which requires approximately 25-35 kg/m2 of rebars, post-tensioned flat slabs only need about 15 to 20 kg/m2 of rebars.
c) Since PT floors are thinner, with limited beams floor-to-floor heights are reduced. This saves 15-30cm per floor compared to a conventional concrete building, and over 30cm per floor compared to a compound steel and concrete building. This can provide extra rentable space within the same overall building height. In a 10-floor building can have one more floor at same height.
2. Reduced Construction time
a) The reduction in materials used and the simplicity of the formwork, simpler slab soffit, limited beams ensure that construction of a floor can be completed faster. Post-tensioning saves time in these areas:
b) Slab formwork and props can be removed earlier. It is quite common to stress the tendons 2 to 3 days after the pour. Once stressing is complete, formwork can be stripped immediately and moved to a subsequent pour.
3. Reduced Floor Vibration, counteract deflections and cracks
Post-tensioning produces two key characteristics in concrete that significantly reduce vibration and counteract deflections. First, the profile of the cables within the concrete produces a load balancing effect. Post-tensioning effectively carries a significant portion of the slab weight so that the concrete slab does not feel its own weight therefore reduced deflections or sag. Second, the slabs are designed to remain uncracked under normal loading. When slabs remain uncracked, they have a much higher stiffness.
4. Architectural Flexibility
Post-Tensioned Slab has an advantage over others as it makes a very efficient base for floor design with thin slabs and columnless spaces in larger spans. It provides an architect the freedom to work freely with his designs especially in offices and residential buildings.
PT allows you to design longer unsupported spans that are strong with thinner floors. This makes post-tensioning an ideal technique for creating concrete slabs for expansive structures such as parking garages, auditoriums, mall, conference center, roofs, customized architectural designs, extended cantilevered slabs for exquisitely designed balconies and other futuristic architectural features.
5. Sustainability
Using post-tensioned concrete in slabs significantly reduces concrete and steel quantities in the structure when compared to conventional concrete or slab construction. Reduction in concrete materials reduce cement consumption which is a contributor to greenhouse gas emissions. Furthermore, there are reductions in other building components as well, including building façade and mechanical equipment. Thus, the environmental impact is minimized throughout the life cycle of the building through diminished material consumption, faster construction, fewer transportation trips, and fewer disruptions to the local neighborhood during construction.