Diameter of the Tie-Rod with Its Cement Grout

Abstract

Calculating the diameter of the element under test is one of the elements to check before redoing a tie-rod dimensioning calculation. Two examples are given.

See Fig. 6.1.

Fig. 6.1

Source Thesis and Photo Thiago Benjamin Porto-P49

Pulled out of the tie-rod with its grout.

First example of calculations from in situ tests (Fig. 6.2).

Fig. 6.2

Mobility measurement

The formula of the NF standard P94 160–4.

6.1 V/F = 1 / ρ_b V B a

Concrete volume mass ρ_b in kg/m3.

Circular cross section (m²).

Mobility 1,5 10–6 m/sN.

Concrete bulk mass—hypothetical 2500 kg/m3.

Wave velocity inside the tie, hypothesis 4500m/s.

Right section of the reinforcement A.

A = 0,06m²

D = 0,27m.

See Fig. 6.3.

Fig. 6.3

Source Rincent BTP—Recife

Calculation made for this type of anchoring with strands.

Second example (Fig. 6.4).

Fig. 6.4

Mechanical admittance

Mobility 4,46 10–5 m/sN.

Volumetric mass of concrete and bar 2500 kg/m3.

Wave celerity inside the tie rod 4500m/s.

A = 2 E-3 m²

This result is normal, because these bars are sealed in the rock.

D = 0.05m (Figs. 6.5 and 6.6).

Fig. 6.5

Source Rincent BTP—France

Cliff reinforcement bars.

Fig. 6.6

Source Rincent BTP—France

Cliff reinforcement static tests.