When it comes to construction and geotechnical applications, the choice of anchoring materials can significantly impact the stability and integrity of structures. Two commonly used options are the Hollow Anchor Bar and the Threaded Bar.Threaded bars, also known as geostructural threaded bars, are stalwarts in the world of construction and foundation work. These long, straight bars feature threads running along their entire length, providing a strong connection or anchoring point in a variety of materials, including concrete, masonry, and more.Threaded bars are manufactured using a precision thread rolling process, ensuring high-strength and dimensionally accurate components. This precision is crucial for applications that demand structural integrity.Threaded bars are available in a range of materials, including high-strength steel, medium-strength steel, stainless steel (such as 18-8 stainless steel), carbon steel, plain steel, and zinc-plated or hot-dip galvanized steel. The choice of material depends on the specific requirements of the project and environmental conditions.Threaded bars find their place in various applications, including soil nails, rock bolts, micropiles, slope support, dam reinforcement, mountain landslide control, foundation uplift control, and more. Their versatility makes them a go-to choice in geotechnical engineering.In many cases, threaded bars are used in conjunction with a grouting method. This involves connecting components like bottom end caps, corrugated pipes, threaded rods, and coupling sleeves, and inserting grouting pipes to secure the threaded bars firmly in place, enhancing their stability.Hollow anchor bars, also known as hollow core anchors or hollow injection bars, are specialized components with a unique design and specific purposes in construction and geotechnical applications. They consist of a wave-thread steel bar with a hollow center, offering distinct advantages.The thread shape of the hollow anchor bar is similar to ribbed reinforcement, featuring a large pitch and deep teeth. This design not only enhances bonding with cement but also provides excellent adhesion and friction resistance. Additionally, the thread can be extended as needed.There are two main types of hollow anchor bar threads: R thread and T thread. R thread conforms to the ISO10208 standard, while T thread offers more support force due to its deeper teeth. In fact, the adhesive friction force of T thread bars is typically double that of R thread bars of the same type. T thread self-drilling anchor bolts are often favored, especially in micropile applications.Hollow steel bars have a wide range of applications. In loose or collapsed formations, self-drilling hollow anchor bars shine. They solve casing demands, enable quick installation, and allow simultaneous grouting. In water-bearing rock formations, where casings can easily get stuck, the self-drilling anchor system emerges as the practical solution.In some scenarios, hollow anchor bars, such as the R51 self-drilling hollow anchor bar, serve as dust ejector tubes before grouting. These bars play a crucial role in eliminating dust and debris from the drilling hole, ensuring a clean and effective anchor installation.Hollow anchor bars are versatile components used for anchoring, grouting, and tunneling applications. Their specific design and use depend on the project's requirements, making them adaptable to a wide array of geotechnical challenges.The choice between hollow anchor bars and threaded bars depends on several factors:Consider the specific needs of your project. Threaded bars excel in a variety of applications, while hollow anchor bars are particularly well-suited for situations where drilling, anchoring, and grouting must occur simultaneously.Assess the environmental conditions and material requirements of your project. Threaded bars are available in a range of materials. The hollow anchor bar also contains corrosion-resistant types to choose from.If you require high support force and enhanced bonding with concrete, T thread hollow anchor bars may be the better choice. However, for standard applications, R thread bars can be sufficient.If speed and efficiency are crucial, self-drilling hollow anchor bars offer rapid installation compared to the grouting process often required with threaded bars.Both hollow anchor bars and threaded bars play vital roles in construction and geotechnical applications. Your choice should align with the specific demands of your project, considering factors like material requirements, application type, and installation speed. Understanding the unique advantages of each option empowers you to make an informed decision, ensuring the stability and integrity of your structures.Sinorock's team has many years of experience in providing complete geotechnical engineering services. If you have any needs or questions in the field of geotechnical anchoring, please feel free to contact us at sinorock@sinorockco.com
If you want to learn more, please visit our website.
Self-drilling anchors are the advanced type of fully threaded hollow steel tube rods. SDA is a fully threaded rod with an inner and outer diameter hollow steel tube. It is provided with a sacrificial drill bit at the end to facilitate the drilling process, coupler to join two SDA bars, screw nut, base plate, etc. The hollow steel tube has one side sacrificial drill bit and, at another end, tied with nut and steel base plate. A hollow steel tube is placed in the center of the drill hole using a centralizer to maintain its position. The grout, which covers the SDA periphery, protects the SDA under aggressive environment conditions with simultaneous grout ground and grout bar interaction throughout the threaded bond length. Self-drilling sacrificial drill varies based on the rock or soil conditions.
The hollow steel tube has more bending strength and more circumference area compared to the solid steel bar (soil nail) with the same cross-sectional area. Due to these benefits of self-drilling anchor, it has advantages over other for reinforcing solid bars, soil nails, and rock anchors. SDA installation can be done by a small drilling machine that can move in difficult access areas and provide slope protection work in difficult reach. Its application, not just only application to soil and slope reinforcement, but also for tunnel application like forepoling for tunnel advancement.
Components of SDA
One of the main components in this technology is a sacrificial drill bit. It helps the drilling and inserting of SDA operation at the same time. This increases the productivity of the SDA installation. The sacrificial drill bit quality defines improving the SDA technique’s penetration rate, performance, and cost-efficiency.
The rolling process enhances the yield strength of the steel. The fully threaded hollow bar allows drilling using a sacrificial drill bit at one end and another end to connect to the standard drill tool that works simultaneously for drilling and grouting. Full threading length of SDA makes it more beneficial to grate bonding to grout and tube and enable for drill rig connections and couplings.
The couplers’ main aim is to provide the connection between seating of each hollow tube face-to-face connection. This is the main component for the energy transmission from end to end connection of anchor and provides maximum percussive energy to drill bit with lesser losses.
Bearing plate with sufficient thickness of steel plates having a central hole required at the face of SDA. The main function of this plate is to transfer the tension load of SDA to the ground.
The hexagonal nuts are made of high strength steel with properly made by all edges to satisfy the demands of anchor specifications and other operations.
With competitive price and timely delivery, KSQ Technology sincerely hope to be your supplier and partner.
SDA installation, rotary percussion process the rotation, and percussion transfer from the hammer to hollow bar system using the shank connector.
Installation of self-drilling anchors
To drive the hollow steel bar up to the desired depth based on the design requirement using rotary drilling. The cement grout is used to inject a self-drilling anchor, and the most common water-cement ratio of cement grout varies between 0.4 and 0.5. Then the injection process was carried out through the hollow steel tube.
Applications of Self-Drilling Anchors
Self-Drilling Anchors are very suitable for weathered or un-consolidated rock stabilization. This technique is a more superior form of stabilization because the SDA technique is a relatively easy and fast method of installation compared to the outdated methods.
SDAs can be used like monopoles and micropile types because these are drilled piles composed of steel reinforcement with injected grout. These anchors are used like micropile type to stabilize the ground and related foundation problems. These anchors are suitable for tension and compression loads at varying ground conditions.
Self-drilling anchors are most suitable for the stabilization of tunnel strengthening works. Mostly for the soft rock and overburden soil conditions, the SDAs are apt for rooftop protection.
The above pictures describe the implementation of SDA as a reinforcing stabilization element for various works.
If you want to learn more, please visit our website T Thread Self Drilling Anchor Bars.