What is pre tensioning in construction?

Pre-tensioning in construction refers to a technique used primarily in the creation of pre-stressed concrete. In this process, steel strands are initially stretched or tensioned and anchored between the ends of a form before concrete is poured. This tensioning creates compressive stresses in the concrete once it is cured, thus improving its performance under tension and making it less susceptible to cracking.

The reason this method is beneficial is that the compressive forces introduced by the pre-tensioning counteract the tensile loads that the concrete will face once it is in use. This technique is commonly applied in precast concrete production, where elements such as beams and slabs are made off-site and then transported to the construction site.

The other options do not accurately reflect the concept of pre-tensioning:

• The second choice describes a sequence of construction activities but does not relate to pre-tensioning specifically.

• The third option suggests a method involving bonding concrete with wood, which does not pertain to the principles of pre-tensioning.

• The last choice indicates a structural approach that eliminates concrete support, which contradicts the essence of pre-tensioning involving both steel and concrete to enhance structural integrity.