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Variant study of a half-swing staircase by Vetra Betonfertigteilwerke GmbH

Variant study of a half-swing staircase by Vetra Betonfertigteilwerke GmbH

The trial at the Vetra precast concrete plant in Neermoor (a subsidiary of Holcim Deutschland GmbH) focused on optimizing the process chain of a half-swing staircase.

03. April 2023
Paul Holz
Sales Engineer

The challenge was to partially substitute the original conventional reinforcement with the help of optimized structural design and calculated steel fiber dosage. 

A C 35/45 precast concrete of consistency class F2 with 30 kg/m³ steel fibers STABILS 60/70 - 2000 made of high-strength steel with a tensile strength of 2000 MPa was used for the test. The identical concrete quality was used for the reference staircase with conventional steel bar reinforcement. The installation method was retained for comparison. 

Subsequently, a life cycle assessment of the "cradle to factory gate" type was carried out with modules A1 to A3.

The results of the comparison are in favor of the combined reinforcement with STABILS steel fibers.

  • Slimmer component due to reduction of the stair web thickness by approx. 30 percent.
  • Saving conventional reinforcement approx. 120 kg.
  • Savings fresh concrete, from the original 1.5 m³ to 1.14 m³.
  • Reduction of weight with positive effect on logistics.
  • 2 instead of 12 working hours for placing the conventional reinforcement.
  • Reduction of the carbon footprint by 19 percent when using the steel fibers.
Half-swing staircase with STABILS-steel fibers in combination reinforcement

Results of life cycle analysis

 

Declared unit

GWP [kg CO2-Äq / stairs]
Declared modules A1-A3

Variant 1 Stair Vetra
Standard reinforcement

604
Variant 2 Stairs Vetra 
Combination reinforcement Bilstein		 490
Savings 19%

 

Assumptions for life cycle analysis

The declared unit is one piece of precast concrete stairs. The software used is the Industry EPD Tool for Cement and Concrete of the Global Cement and Concrete Association, version 3.2.

The materials, raw materials, energy consumption, etc. required for the production of the precast concrete stairs were provided by the company Vetra Betonfertigteilwerke. Any data gaps were filled by assumptions commonly used in the market.

The specific carbon footprint of steel fibers was provided by BILSTEIN STEEL FIBER. Since a specific data set for these steel fibers is not available in the LCA software, the impact of the CO2 footprint was modeled by combining two existing data sets. For this purpose, a ratio of the data sets "Fibers, steel (100% primary)" and "Fibers, steel (100% recycled)" of approximately 4% and 96% is chosen. The environmental product declaration of the supplier Badische Stahlwerke is available for modeling the steel bars (EPD-BSW-20210265-CBA1-DE).

Life cycle analysis: variant study of precast concrete stairs

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SD_2303_bilstein_en-1.pdf