###### Abstract  
Preloaded bolted connections are one of the most used approaches for anchoring steel structures and equipment. Preloaded is induced by a mechanical tightening of the nut with the required torque. In the case of anchor bolts embedded in a concrete base, the prescribed tightening procedure has to be followed for safe and reliable operation. The present paper addresses the problem of anchoring a new casting pedestal using the original anchor bolts. The aim was to verify the original anchoring system's reliable and safe operation, taking into account the current condition of the bolts. The analysed anchoring bolts are subjected to cyclic (disappearing) stress during the rotation of the casting pedestal. If the interplays between the anchor bolt and the concrete foundation were damaged, production would shut down, resulting in high economic losses. For this reason, the authors used a modified nut with a lightened first thread when investigating the actual state of the anchoring and setting the required preload. The shape and dimensions of the nut were determined based on the results of numerical modelling. The experimental measurements consisted of two phases. In the first phase, the values of axial forces in the anchor bolts at the required preload were set using the designed dynamometers. The second phase was focused on the operational measurements. The methodology of measuring the axial forces and the interpretation of the results obtained, including a comprehensive view of the anchoring safety, provides relevant evidence of the functionality and effectiveness of the proposed solution. Based on the results of the operational measurement and the prescribed handling of the casting pedestal, the lifespan of the anchoring was determined to be 3650 days under the loading cycles to date. fatigue; anchor bolt; casting pedestal; measurement +
Footnote †: journal: Applied Sciences  
16 November 2021 28 November 2021 28 November 2021  
[PERSON] et al. [6] studied the failure analysis of anchor bolts used to fix a seawater booster pump in a nuclear power plant. They concluded that the failure was due to screw corrosion. The failure modes of anchor bolts under cyclic loading were investigated by [PERSON] et al. [7]. They analysed the mechanical responses of bolts with different diameters and applied different cyclic loads. The behaviour of the bolted joints is also affected by the preload in the bolt. The preloaded anchor bolts were investigated and described in papers [8; 9; 10]. [PERSON] et al. [11] proposed a stress reduction calculation method to calculate the actual stress of the bolt from the measured value registered by the pulse pre-pumped Brillouin optical time domain analysis (PPP-BOTDA) technology of different types of bolts embedded in concrete with resin as an anchoring agent. To investigate the bolts' inner force quantities and displacement, [PERSON] et al. [12] analysed the influence of the anchorage length using the load transfer method. The obtained results confirmed that the increasing anchorage length caused significant unevenness of the interfacial shear stress distribution, and a greater bearing capacity of the anchoring bolt. [PERSON] [13] investigated the mechanism of force evolution in bolts and found that bolts with different anchorage lengths should be used to support roadways with different deformation characteristics. His research concluded that the bolts should be kept in the deformation phase of the anchoring force as much as possible when the surrounding rock deforms. However, dynamic loading also affects the lifespan of the bolt joint [14; 15]. [PERSON] et al. [16] considered the possibilities of reducing the vibration amplitudes of the converter base through design changes and changes in the pre-stress of the screw connections. However, the high stress in anchoring bolts, among other things, causes serious deformation and damage of equipment, as well as steel constructions [17; 18; 19].