1. בית
  2. הנדסה
  3. מרכז התיכנון
  4. מטות פלדה לאחר התקנה
  5. Design Guidelines
  6. Rebar design for high temperatures

HOW TO DESIGN REBAR TO WITHSTAND FIRE

Rebar design guidelines for high temperatures

Hilti post installed rebar fire test

The performance of buildings is clearly reduced when they’re subjected to high temperatures. Mortars also lose their load capacity.

But for many years there were no standardized guidelines to design rebar when subjected to fire.

HOW TO DESIGN WITHIN EUROCODE 2 GUIDELINES

Hilti rebar anchorage length design

That’s because the TR023 guidelines, used to test products, only covered static conditions and not fire conditions.

Instead engineers had to rely on reports from technical institutes, such as DIBT and CSTB. But these tests weren’t standardized and design safety concepts weren’t necessarily compliant with Eurocode 2’s safety margins.

What changed in 2015

In 2015 the EAD 330087-00-0601 guidelines were endorsed. These showed how to evaluate rebar connections in fire. They replaced the TR023 guidelines for rebar connections with mortar. Now you can use EAD 330087-00-0601 to:

  • Assess the mechanical behavior of mortars in fire conditions as well as static conditions
  • Be compliant with Eurocode 2 safety margins.
  • Manufacturers can also use a standardized method to qualify mortars for post-installed rebar applications in fire.

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Hilti mortars are designed for rebar in fire

At Hilti we developed the first industry-approved mortars for fire applications – Hilti HIT-RE 500 V3, Hilti HIT-HY170 and Hilti HIT-CT 1.

You can use these in your design to:

  • Design by inputting a specific temperature, which can optimize your design solution.
  • Design every static application covered by EAD 330087-00-0601 which is subjected to fire – including beam-to-beam, beam-to-column, slab-to-wall, slab-to-slab.
  • Design system connections compliant with Eurocode 2 safety margins.
Post installed rebar anchorage length Eurocode 2 solution

Hilti HIT-RE 500 V3

Post installed rebar anchorage length Hilti HIT rebar design method

Hilti HIT-HY 170

Hilti offers you all the necessary tools to design according to the new code including our state of art Profis Rebar software, our technical support and our extensive technical library.

Hilti design data

We offer data tables for standard applications, such as slab-to-slab, slab-to-wall.

You can also access data tables for each of our fire-approved products based on its mechanical behavior in fire conditions, as reported in its ETA.

These data tables are attached to the product information, which you can find in our product pages.

Hilti PROFIS Rebar design software

Our Hilti PROFIS Rebar 3D design software can also design a wide range of rebar applications for fire. 

STANDARD AND CUSTOMIZED DESIGN FOR REBAR IN FIRE

Hilti rigid rebar connection with straight bars

You can find the reduction factor to be applied to the bond strength in the ETA of each approved product. This is required when you’re designing according to EAD 330087-00-0601 and Eurocode 2. You can then estimate a standard design or customized design:

  • Standard design – this estimates the time needed to evacuate a building. Use the design values in the evaluation reports of fire-approved products
  • Customized design – estimate the temperature in the connection in specific fire conditions and for how long

How the new EAD guidelines help design

Using a product approved based on EAD 330087-00-0601 can help your design in several ways:

  • Transparency – there are standardized rules for the testing process and data assessment
  • Flexibility - you can perform a wide range of analyses from global structural analysis to member analysis
  • Unlimited scope – you can design every application for fire, including slab-to-slab, slab-to-wall, beam-to-wall, beam-to-column or beam-to-beam
  • Safety - the testing process and results assessment are based on EC2 safety margins

RELATED HILTI CHEMICAL ANCHORS FOR POST-INSTALLED REBAR IN FIRE