Who is responsible for determining the structural model of the skirt base anchor bolts?

It is inappropriate to design this first and then have the manufacturing factory handle it; after all, the calculation software for this equipment can only determine one diameter. Whether the bottom of the anchor bolts is in the form of an anchor plate or something else, as well as the strength of the anchor bolts within the foundation, all these need to be calculated by structural engineers. Even if the manufacturing factory refers to relevant standards and designs accordingly, can it be held responsible for the accuracy of those designs? Secondly, talking about supply: many owners think that since they have already purchased the equipment, it would be convenient to have the manufacturer provide the anchor bolts as well, as it saves money and effort. In fact, it saves neither money nor effort; the cost is ultimately borne by the customer, and there is also a risk of unprofessionalism or insufficient length provided by the manufacturer. It also affects the project timeline; you can’t expect the foundation bolts to arrive along with the equipment, right? That would affect on-site installation, and if the goods are supplied in advance, there may be a problem of storing them temporarily since they might not be needed on site at that time. In fact, the best approach is for the civil engineering contractor to purchase and install the anchor bolts at the same time as constructing the foundation based on the civil engineering drawings; this is the most common and simplest method.

Check the contract terms. If it is a design institute, such an institute has a structural engineering department; the mechanical engineering department submits requirements to the structural department, which then designs the anchor bolts. These are designed and constructed simultaneously with the civil foundation of the tower, which is beneficial for both quality and schedule. If it is the owner who asks the manufacturer to produce it, that’s also acceptable. The manufacturer can refer to the established catalogues provided by the design institute to calculate values such as the diameter, quantity, length, thread length, and exposed length of the anchor bolts, and then provide these figures to the entity responsible for designing the civil foundation.

The general procedure is as follows: For the anchor bolts of regular equipment, after they are designed by the equipment specialists, they are submitted to the civil engineering team for coordinated design; these anchor bolts are also handled by the civil engineering team in terms of procurement, manufacturing, and installation. As for the anchor bolts of large-scale equipment, such as important towers, they are usually designed by the equipment specialists and sent to the manufacturer, who then manufactures the anchor bolts and provides the positioning plates. The positioning plates and bolts are installed in place by the civil engineering team at the construction site. If pre-installed bolts are used, they are generally provided along with the equipment by the manufacturer

Equipment manufacturers generally cannot determine the model, structure, length, etc. of anchor bolts, as it is necessary to perform calculations on the selected anchor bolts.

Equipment manufacturers generally cannot determine the model, structure, length, etc. of anchor bolts, as it is necessary to perform calculations on the selected anchor bolts.

Even when selecting according to standard specifications, there are many structural forms available, with varying lengths as well; how do equipment manufacturers determine and calculate these values?

I completely agree with you. At present, it is impossible to determine the structure and length of the anchor bolts; generally, equipment manufacturing units lacking professionals in structural engineering find it difficult to carry out such calculations.

Generally, straight forms are used, along with form rings and anchor plate rings. For larger diameters, steel pipes or shaped steel are used for reinforcement. When reinforcing the tower foundation, the rings equipped with foot bolts are placed inside, and after concrete is poured they remain buried there. Once the tower is delivered, the forms are removed, the tower is lifted into place, and the forms are then sold as scrap metal.

Personally, I feel that if things are designed according to your approach, it will either lead to problems or be rather wasteful. The foundation bolts indicated by the equipment calculation software show only the diameter; the calculations are primarily based on shear forces, with the aim of ensuring that the bolts do not break under lateral loads. Moreover, anchor bolts also face the issue of pull-out resistance, and this capacity is determined by the way they are embedded in the foundation as well as the depth to which they are inserted. Of course, in the vast majority of cases, the choice is made based on diameter and the magnitude of the force, but this certainly does not cover all situations. Typical engineering companies determine the diameter of the foundation bolts for the equipment, and also provide calculated values such as the bending moment for large towers. There are methods for calculating this bending moment in both civil engineering and mechanical engineering, but there are significant differences due to the different approaches taken. The values provided by mechanical engineering are only for reference; it is the civil engineering team that determines the type and length of the anchor bolts after conducting relevant calculations. I personally think this is more reasonable.

Also, your approach has a significant impact on on-site management. It’s not a problem for small projects, as there are only a few towers in those cases. But when a project involves dozens or even hundreds of towers, and there are five or more manufacturers responsible for producing those towers, then differences in the progress of civil work, variations in the delivery schedules of the equipment manufacturers, differences in the specifications of hundreds of foundation bolts, as well as differences in the types of materials used and their arrival times, all pose serious challenges to on-site management.