Produced from seamless pipes, the self-injected tie-rods or micro-posts have as its main features, the high mechanical strength simultaneously acting as drilling element and structural shielding. They present a hollow section within its whole extension, allowing the injection of a cement solution on tensions varying from 25 to 100 bars.

The one bar tie-rods are produced from solid bars having as main feature, the high mechanical strength, providing the planners with a better distribution, increasing the structural spacing.