Anchor bolts are connectors used to securely fix precast components to concrete foundations or other structures. During the installation of precast components, anchor bolts act as a bridge, ensuring a tight connection between the precast component and the foundation. Depending on the installation method, anchor bolts can be divided into pre-embedded anchor bolts and post-installed anchor bolts.

Pre-embedded Anchor Bolts: Pre-embedded anchor bolts are installed inside the precast component during the precast component manufacturing process. These anchor bolts are fixed in the designated position when the precast component is poured with concrete. After the component is installed on site, it is tightly connected to the foundation using nuts and other connectors. The advantage of pre-embedded anchor bolts is their high installation precision, effectively ensuring the installation quality of the precast component.

Post-installed Anchor Bolts: Post-installed anchor bolts are installed into the foundation after the precast component is installed on site, using methods such as drilling. These anchor bolts are suitable for scenarios requiring flexible adjustment of the installation position. Post-installed anchor bolts offer relatively flexible installation, but it is necessary to ensure the accuracy and depth of the drilling to guarantee the anchor bolt's anchoring effect.

Why are they so crucial in building construction?

If prefabricated components are the "flesh and blood" of a building, then anchor bolt connections are its "skeleton." Their importance is reflected in the following vital aspects:

1. Fundamental Guarantee of Structural Safety: Resisting Loads and Disasters

This is the most core and indispensable responsibility of anchor bolts.

Load Transfer: Buildings must withstand their own weight, service loads, wind loads, snow loads, and even seismic forces. These forces need to be transferred between various components through joints. As a key part of the joint, anchor bolts bear complex stresses such as tension, shear, and bending, ensuring that the entire structural system works collaboratively, rather than disorganized.

Earthquake Resistance and Disaster Prevention: During an earthquake, buildings experience enormous horizontal forces and deformations. Anchor bolts embedded in column bases and beam ends must have sufficient ductility and strength to allow the structure to undergo a certain degree of plastic deformation to dissipate seismic energy, while preventing component detachment or overturning, buying precious time for escape. The failure of one anchor bolt can lead to the destruction of the entire joint, subsequently triggering a cascading collapse.

2. Core Technologies for Prefabricated Construction: The Cornerstone of Precision and Efficiency

The advantages of prefabricated buildings lie in their speed and accuracy, which heavily rely on anchor bolts.

Precision Control: Pre-embedded anchor bolts are installed in a factory environment, achieving millimeter-level positioning accuracy. This enables on-site "hole-to-hole" installation, allowing large components to be installed seamlessly, significantly reducing on-site adjustments and cutting work.

Improved Efficiency: Reliable anchor bolt connections mean rapid tightening. Workers only need to hoist the components into place, insert high-strength bolts, and tighten them to complete the main structural connections, significantly shortening the construction period.

3. Ensuring Building Integrity and Durability

Overall Stability: Through the effective connection of anchor bolts, dispersed prefabricated components are integrated into a spatial structure with sufficient rigidity and stability to collectively resist external forces.

Sealing and Corrosion Protection: Many anchor bolt connection nodes also integrate sealing strips and anti-corrosion designs to prevent moisture and harmful gases from penetrating the connection area, protecting the internal steel and prestressing tendons, and extending the building's lifespan.

Although small, anchor bolts play a crucial role in the installation of precast components. They not only ensure the installation accuracy and stability of precast components but also improve construction efficiency and enhance the seismic performance of buildings. In modern building construction, anchor bolt installation has become an indispensable part. However, please note the following key points in construction:

1. Anchor Bolt Selection and Design

During the design phase of precast components, it is necessary to select the appropriate anchor bolt type based on the component's intended use and stress conditions. Pre-embedded anchor bolts are suitable for scenarios requiring high precision and fixed installation positions; post-installed anchor bolts and chemical anchor bolts are suitable for scenarios requiring flexible adjustment of installation positions.

2. Installation Accuracy

The accuracy of anchor bolt installation directly affects the installation quality of precast components. During installation, high-precision measuring tools are required to ensure the accurate positioning of the anchor bolts. For pre-embedded anchor bolts, the pre-embedded position of the anchor bolts must be strictly controlled during the production of precast components.

3. Quality Inspection

After installation, the installation quality of the anchor bolts needs to be inspected. The anchoring force of anchor bolts can be ensured to meet design requirements through methods such as pull-out tests and ultrasonic testing. For chemical anchor bolts, the curing status of the chemical adhesive also needs to be tested to ensure the reliability of the anchor bolt.

4. Corrosion Protection Anchor bolts are typically exposed to complex environments and are susceptible to corrosion. Therefore, anti-corrosion treatments such as galvanizing and applying anti-corrosion paint are necessary to extend the service life of the anchor bolts.