I. What is a 9-shaped anchor bolt?
The 9-shaped anchor bolt is a one-piece pre-embedded anchor bolt, made from a single piece of round steel bent without splicing or welding. It consists of three main parts: a threaded section, a straight embedded section, and a 9-shaped closed hook.
During construction, it needs to be pre-embedded in the concrete foundation. The exposed thread on the upper section, along with a nut, flat washer, and adjusting wedge, is used to lock and fix the steel column and equipment base. The closed-loop hook, deeply embedded in the concrete, significantly increases the contact area with the concrete, firmly locking the base and effectively resisting equipment vibration, vertical tension, and lateral overturning forces, thus preventing potential engineering problems such as bolt pull-out and foundation loosening.
Unlike the L-shaped anchor bolt with only a 90° right-angle opening, the 9-shaped anchor bolt forms a complete ring structure at the bottom, resulting in more even stress distribution. It remains stable even under heavy loads and high-frequency vibration conditions, making it a standard fastener for factory buildings, tower cranes, and large machinery foundations.
II. Core Product Advantages of 9-Shaped Anchor Bolts
1.Enhanced Anchoring Capacity: The closed-loop hook design improves pull-out resistance by approximately 40%, making it less prone to loosening under heavy loads and high vibrations, meeting the load-bearing standards for heavy infrastructure.
2.The unibody structure is robust. It is formed by hot bending of a single round steel bar, eliminating the risk of welding breakage, ensuring uniform overall strength, and extending service life.
3.Flexible specifications and customization support: Standard stock covers a wide range of commonly used diameters, and the total length, thread length, and hook size can all be non-standardized according to the construction drawings to meet the construction needs of various special foundations.
4.Multiple anti-corrosion treatments are available. Suitable for various environments including indoor dryness, outdoor exposure, coastal salt spray, and chemical corrosion. A variety of anti-corrosion layers extend the service life outdoors.
5.High adaptability to civil engineering construction. It can be used with pre-embedded positioning templates, making it less prone to displacement during pouring. It is easy to operate and its versatility covers the vast majority of civil engineering pre-embedded projects.
III. Material, Strength Grade, and Surface Anti-corrosion Treatment
1. Mainstream materials and strength grades
-Ordinary carbon steel Q235B, grade 4.8: suitable for light steel structures, small supports, and ordinary factory columns, with high cost performance
-High-strength Q355B and 45# tempered steel, grade 8.8: specially designed for heavy-duty equipment such as tower cranes, fan bases, crushers, and large machine tools.
-304/316 stainless steel material: Excellent rust resistance, ideal for coastal areas, chemical plant areas, and humid and corrosive environments.
2. Surface anti-corrosion process
-Blackened blanks: Lowest cost for short-term use in dry indoor environments.
-Hot-dip galvanizing: the mainstream choice for outdoor projects, corrosion-resistant, durable, and with the best cost performance.
-Dacromet/Zinc plating: In high-humidity, coastal salt spray areas, its corrosion resistance far exceeds that of ordinary galvanizing.
IV. A simple comparison between 9-shaped and L-shaped anchor bolts.
| Project | L-type anchor bolts | 9-shaped anchor bolts |
|---|---|---|
| Hook form | 90° right-angle hook | End 180° back bend closed hook |
| Anchoring force | generally | Stronger, not easy to pull out |
| Applicable load | Light equipment, small steel structures |
Medium and heavy equipment, steel columns of factory buildings, heavy-duty foundations |
V. Main application scenarios of 9-shaped anchor bolts
1.Pre-embedded fixing of portal steel columns and frame columns in steel structure factory buildings
2.Large concrete foundations for tower cranes, overhead cranes, and lifting equipment
3.Bases for heavy industrial equipment such as air compressors, stamping machines, crushers, and generator sets.
4.Tank supports, large pipeline supports, and foundations for large outdoor billboards
5.Wind turbine foundations, small bridge bearings, and heavy mining machinery foundations
VI. Frequently Asked Questions
Q1: What is the standard embedment depth for 9-shaped anchor bolts?
A: For standard construction, the embedment depth is 25 times the bolt diameter. However, for high-load scenarios such as tower cranes and heavy equipment, the embedment depth needs to be increased according to the design drawings to improve the anchoring safety factor.
Q2: Can you produce non-standard 9-shaped anchor bolts?
A: The factory supports full-size customization, with adjustments to the total bolt length, exposed thread length, hook inner diameter, and rod thickness. Mass production is available according to civil engineering drawings.
Our company specializes in producing standard 9-shaped anchor bolts. We have our own forging, bending, and galvanizing production lines, ensuring a stable supply. Before shipment, we rigorously test the thread accuracy, overall strength, and galvanizing thickness. We supply bulk orders to engineering companies, steel structure manufacturers, and equipment manufacturers. We support custom orders based on drawings and offer complete sets of nuts and washers. We accept both domestic and international orders. Please contact us anytime for specifications, pricing, and delivery time.
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