Installation Steps of Prestressed Anchorage and Calculation Method of Blanking Length

single hole anchor
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Prestressed anchorages are generally used in bridges. The installation process and steps have clear regulations, and the length of the blanking needs to be calculated according to the project. Today, we will focus on discussing this aspect with you which I hope will be helpful to you.

The construction and installation method of prestressed anchorage is a small anchorage construction and installation. It is a simple construction with a diameter of 28-75mm and a depth of 1~Sm in the rock where the anchorage is installed. The simple construction can be drilled or manually drilled, and then charge explosives. The simple construction method can be used to excavate foundation pits, mine stones, loosen frozen soil, etc.

  1. The general method of anchorage construction and installation is to place a small number of explosives at the bottom of the hole. After several constructions and installations, it expands into a spherical shape, and finally, the explosives are loaded for anchor construction and installation. Compared with the hole anchor construction and installation method, this method has the advantages of good anchor construction and installation effect, high work efficiency, fast progress, and low explosive consumption. This method is often used in the construction of short piles with shallow foundations.
  2. The complex construction and installation of anchorages are to strictly control the explosion energy and explosion scale through certain technical measures, so that the sound, vibration, damage area, and the collapse range of broken objects are controlled within the specified limits. It is often used in cities and factories, and complex old bridge buildings or structures are often required, such as buildings, factories, chimneys, water towers, and various foundations.

The blanking length of the prestressed tendons must meet the requirements of use, and the mobile crushing station must prevent the waste from being too long. The calculation of the blanking length of the prestressed rebar should consider factors such as the type of the prestressed bar, the form of anchorage, the elastic retraction rate, the length of the tension, the length of the component channel, the tensioning equipment, and the construction method, etc. The beam is tensioned at both ends, so the length of each strand is determined by the following formula: L=L0+2 (L1+L2+L3+L4) where L0 is the length of the channel of the member; L1 is the thickness of the working anchor; L2 is jack length; L3 is tool anchor thickness; L4 is length margin (usually 100mm).