Connection between concrete columns and continuous floors with integrated steel beams

Connection between concrete columns and continuous floors with integrated steel beams

Dolganov, Mikhail (TU Delft Civil Engineering and Geosciences)

Yang, Yuguang (mentor)
Hoogenboom, Pierre (graduation committee)
Houben, Lambert (graduation committee)

Delft University of Technology

Civil Engineering | Structural Engineering

2019-11-27

This research studies a simplified connection between one storey high concrete columns and the continuous floors with an integrated steel beam, of the THQ type, carrying hollow core slabs and covered by a reinforced structural screed. The final goal is to determine the strength of the connection. This is done with a calculation method, which may be used outside of this research by designers for an estimation of the design strength of their connection. A simplified design for the connection is set up as a reference design. It is loaded by two load combinations of the use stage of the building, a symmetric and an asymmetric load combination. A behaviour prediction is set up for the reference design under these load combinations. Based on that prediction, additions to the design are studied, which should improve the connection strength. Two adjusted designs are chosen to analyse alongside the reference design: a design with the integrated steel beam supported by additional steel webs at the connection and a design with the integrated steel beam being filled with mortar at the connection. The three designs are numerically modelled and analysed with the Finite Element Analysis (FEA) in DIANA FEA. With the results of the numerical analysis, the design strength of the connection is calculated. The numerical results show that the structural screed and the bottom column are the governing connection parts. The structural screed in the reference model is influenced most by the steel webs of the beam underneath and a limited load transfer area, which leads to higher stresses in the concrete. In the adjusted models this situation is improved, with the model with a mortar filling being the best adjustment, as it provides the maximum load transfer area. The bottom column is most affected by the bending of the steel beam flanges due to the load of the floor, causing a large load to be transferred over a small area at the column edges. The adjusted models do not show a strong improvement here, as the adjustments are limited in the stiffening of the beam flanges. The calculation of the design strength of the connection shows the adjustment of the mortar filling to be the best solution. However, the final design strength is low compared to the design strength of the concrete in the structural screed or the columns. This is the result of the horizontal tension in the structural screed, which reduces the concrete strength. A better result may be obtained by the removal of the structural screed at the connection and the placement of the concrete column directly on top of the steel beam. This adjustment needs a further research.
The conclusion is that the researched design in its current form is not effective enough to be applied in practice, but its drawbacks can be solved with a few adjustments to the design, making it an effective design solution.

THQ
FEM
Connection

http://resolver.tudelft.nl/uuid:4dc92753-159c-4322-a8b9-ca634fa37e47

Student theses

master thesis

© 2019 Mikhail Dolganov