Best Earthquake Resistant Connection
What is Hilti?
Founded in 1941 in Schaan, Liechtenstein, Hilti is already world-famous and well-regarded for power tools used in construction worldwide. Their decades of research have gradually modernized construction tools, making today’s massive construction projects easy and smooth. I was talking about “Hilti,” whose slogan is “Making Construction Better”, Engineer Martin Hilti and his brother Eugen started this journey 84 years ago. From a small 160 sq. km country between Austria and Switzerland, they now operate directly in over 120 countries. There are also many partner market countries. Hilti is not only known for powerful construction tools but has also become a trusted name in construction fastener services since 1973.
What is Meant by Connection in Construction?
Engineers in the modern countries of the world and even in neighboring India know about this, unfortunately, many of our country’s engineers are still unaware of these terms. In various contexts of construction work, mechanical and chemical anchoring, and post-installed rebar are needed for connecting different parts of a construction or built structure. Even for post-construction additions or modifications, this work is essential. These connections play a vital role in structures during earthquakes.
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Context of Connections in Construction
If I talk about anchoring, it means connecting steel structures with concrete through steel base plates. Now this connection can be of various types for different reasons, such as: for construction platforms, for formwork, for tilt-up, for safety barriers or enclosures, for connecting some frame with shore piles or diaphragm walls, for installing various rail lines, for cranes used in transporting people or goods related to construction, for pulling various pipes or lines, for adding various trays or hooks, for different signal connections in large structures, for facade items on the outside of buildings, anchoring work is extremely important also.
If I give examples of post-installed rebar, then in new construction, connecting starter bars with poured concrete, bridge railings, connecting slabs-retaining walls-mats with shore piles or diaphragm walls, wall-column-beam-slab extension, wall to wall – slab to slab or connecting any frame to another frame, correcting rebar installation mistakes during concrete pouring, strengthening beams, columns, slabs in repair or retrofitting of old constructions—post-installed rebar is used in these important tasks.
“The Best Earthquake Resistant Connection in Construction Means Hilti“
Engr. Md. Golam Hossain Farhan
General Practices for Construction Connections by Engineers in Bangladesh
Among engineers in Bangladesh, some common problems are seen in the practice of construction connections. In most cases, they use common royal bolts for mechanical anchoring, which are not actually designed for specific loads. The use of chemical anchors is also limited, and even when used, most of the time low-quality chemical anchors are chosen, which poses a threat to project durability and safety.
Also, many times connections are made just by grouting, without proper anchoring, which is done without any engineering analysis. A common mistake among engineers is using the “thumb rule,” where anchor embedment depth is determined only by multiplying the diameter by 10. This does not involve actual load calculation and does not consider the quality of concrete, the nature of the structure, or surrounding conditions.
The most common and dangerous practice is breaking concrete to take out rods from inside and attaching new rods to them and pouring concrete, which weakens the structure, wastes the owner’s money, and happens only due to the lack of knowledge of contractors and consultants.
As a result, constructed structures fail to take their specified load, and over time, they develop cracks, loose connections, or complete failure. This unscientific and unskilled method creates safety risks in the construction industry, leading to accidents and financial losses, and could be a cause of certain disasters during earthquakes.
What Does BNBC Say About Construction Connections?
Bangladesh’s National Building Code (BNBC 2020) provides specific guidelines about connections, especially in Part Six, Appendix K, K.2.2 and K.2.3, which provide important instructions about mechanical and chemical anchors.
BNBC 2020, Part VI, Appendix K – Mechanical Anchor Guidelines
In mechanical anchors, minimum anchor depth, spacing, and allowable load according to concrete grade must be considered.Only tested and internationally recognized anchors approved by ICC-ES, following ACI 355.2 Pre-qualification, should be used.Advanced technology anchors are recommended to ensure high load-bearing capacity.
BNBC 2020, Part VI, Appendix K – Chemical Anchor Guidelines
In post-installed chemical anchors, minimum bond strength, concrete condition, and correct installation methods must be followed.
Only tested and internationally recognized anchors approved by ICC-ES, following ACI 355.4 Pre-qualification, should be used.Engineers must determine high-quality chemical anchors through proper load calculation and analysis.Hybrid injection systems must be used for proper installation to avoid bubbles or voids during installation.
BNBC Guidelines on Post-Installed Rebar
In post-installed rebar, high-quality chemical anchors must be used; if considered as an anchor, then only tested and internationally recognized anchors approved by ICC-ES, following ACI 355.4 Pre-qualification, should be used.If considered as rebar for development length, then ACI 318 must be followed since this is our code’s source, and in this case, AC 308 must be followed for design and specification.AC308 is the Acceptance Criteria for Post-Installed Chemical Anchors in Concrete Elements set by the International Code Council Evaluation Service (ICC-ES). It sets standards for post-installed rebar and chemical anchors in concrete.
Chemical systems must pass tests for Bond Strength, Creep Resistance, Temperature sensitivity, and sustained load performance Installation sensitivity is tested (e.g., hole cleaning, moisture, and embedment depth).Under AC308, post-installed rebar can be designed like cast-in-place rebar, helping determine development and splice length according to ACI 318 code.Post-installed rebar is typically used for slab-to-wall connection, foundation extension, and connecting any frame to another in existing concrete members to strengthen them.For earthquake-prone areas, adhesive anchors must be tested according to AC308 and ACI 318 Chapter 17 to show proper resistance characteristics to seismic loads.
How Hilti Provides Solutions for Construction Connections
Hilti provides advanced design solutions for construction connections through Hilti PROFIS Engineering Software. This software allows design according to ACI 318 and BNBC 2020 codes, where shear load, tension load, and moment load can be applied to check connection failure.
✅ With Hilti PROFIS Engineering Design:
✔ For Anchor to Concrete Design: Steel Failure, Concrete Breakout Failure, and Pullout Failure are checked in Tension. In Shear: Steel Failure, Concrete Edge Breakout, Pryout Failure, and Combination Failure are tested.Design is ensured with utilization and optimization above 90%.
✔ For Post-Installed Rebar Design: When designed as Chemical Anchor: Tension, Shear, and Combination Failure are checked.When designed for Development Length: All factors are considered following ACI 318.
✔ PROFIS Engineering Report: PDF report of all designs can be downloaded, with detailed calculation and references.Installation guidelines are included in the report to ensure correct installation.
✔ Hilti Anchor and Chemical Anchors Certification: Hilti’s Mechanical Anchor, Chemical Anchor, and Chemicals for Post-Installed Rebar follow ACI 318 – 355.2 & 355.4 and AC308.Certified for 50 and 100 years by ICC-ES, ensuring long-lasting connections.
✔ Design for Both Static and Seismic Load: Design can be done for both Static Load and Seismic Load using PROFIS Engineering Software, ensuring earthquake-resistant connections.
Why Hilti Means the Best Earthquake-Resistant Connection in Construction
Because only Hilti gives you design-based solutions. Before making the connection, you can verify if your calculated load can be properly taken by the connection according to Bangladesh National Building Code. You can check if the connection can withstand additional seismic load or earthquake vibrations. You will get certifications from the world’s most renowned construction codes, ensuring your connection and long-term durability.
So, let us not ignore construction connections and create disasters. Let’s bring in Hilti and ensure earthquake resistance of our structures.
This article was originally published on March 18, 2025, on Kalerkantho under the title “The Best Earthquake-Resistant Connection in Construction Means Hilti“