Composite frames with slim floors

Tschemmernegg, F

doi:10.1016/s0143-974x(98)00014-5

Cited by 2 publications

(2 citation statements)

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“…As illustrated in Figure 2, the concrete was arranged in such a way that it protected the load-bearing inner steel parts so that it was superfluous to apply additional fire protection. This joint was partly adopted from the joints used in the so-called “Millennium Tower” (Taus, 1999; Tschemmernegg, 1999; Tschemmernegg, 1998), where it was used in slim floor construction. The design was extended to composite beams and optimised for fire conditions using CFDST columns, shear panel and substitute flange as new key load-bearing components.…”

Section: Structural Layout and Loading Of The Considered Unbraced Composite Frame And Jointsmentioning

confidence: 99%

How bracing and heating regimes influence the fire performance of composite frames

Bahr

2020

JSFE

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Purpose Unbraced one-bay composite frames are an interesting load-bearing structure for buildings with up to three storeys. However, their fire design is demanding given the lack of simplified design methods. This paper aims to deepen the understanding of the load-bearing behaviour of both unbraced and braced frames when exposed to fire. Design/methodology/approach In a previous paper, a numerical model for the fire design of these frames was established and validated with good agreement against fire tests. In the current paper, this model was used to compare the typical differences between braced, semi-braced and unbraced composite frames under fire conditions. Further studies addressed the effect of different heating regimes, i.e. partial fire exposure of the columns in the frames and varying location of the ISO standard fire. Findings Numerical investigations showed that it is necessary to take local failure and deformation limits of the fire-exposed frames into account. On this basis, unbraced composite frames can compete with braced frames as they have to endure less thermal restraints than braced frames. Originality/value In contrast to other investigations on frames, the numerical model is able to take into account the shear failure, which is especially important within the frame corners. Using this model, it is shown that limited sway is reasonable to reduce thermal restraints and hence local stresses. In this regard, the concept of semi-rigid composite joints with a distinct amount of reinforcement has proven to be very rational in fire design.

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Section: Structural Layout and Loading Of The Considered Unbraced Composite Frame And Jointsmentioning

confidence: 99%

How bracing and heating regimes influence the fire performance of composite frames

Bahr

2020

JSFE

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“…In the following, it is referred to this type of joint as “joint with CFDST columns”. This joint was partly adopted from the joints used in the so-called “Millennium Tower” (Taus, 1999; Tschemmernegg, 1999; Tschemmernegg, 1998), where it was used in slim floor construction. The design was extended to composite beams and optimized for fire conditions using CFDST columns, shear panel and substitute flange as new key load-bearing components.…”

Section: Development Of An External Semi-rigid Composite Joint With Concrete-filled Double Skin Tube Columnsmentioning

confidence: 99%

On the fire performance of unbraced composite frames

Bahr

2018

JSFE

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Purpose The purpose of this study is to gain a deeper understanding of the structural behaviour of fire-exposed unbraced composite frames. Designers to date paid little attention to unbraced one-bay composite frames as structural system. There are two main reasons for this. First, codes lack simplified methods for the fire design of these frames due to their sway and the linked P-Δ effects when subjected to fire, which complicates the design. Second, it is demanding to construct external composite joints for the regarded one-bay frames. Thus, external joints in composite constructions are mostly constructed as steel joints. Nevertheless, these frames offer advantages. These include increased usable space and flexibility in the building’s use, large spans, fast construction times and inherent fire resistance. Design/methodology/approach To profit from these benefits, two different external semi-rigid composite joint were developed for the considered one-bay composite frames. The first solution based on concrete-filled steel tube columns and the second on concrete-filled double skin tube columns. Furthermore, a numerical model was established to study the fire performance of unbraced composite frames. The model was validated against four fire tests on isolated composite joints and two large-scale fire tests on unbraced composite frames. Findings Overall, the predictions of the numerical model were in good agreement with the test results. Thus, the numerical model is appropriate for further investigations on the fire performance of unbraced composite frames. Originality/value The sequence of construction results in significant stresses in the steel section, which creates difficulties in numerical modelling and may account for the relatively few studies carried out at room temperature. For the fire design, there was, to the best knowledge of the author, to date no numerical model available that was capable of considering the sequence of construction.

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Composite frames with slim floors

Cited by 2 publications

References 0 publications

How bracing and heating regimes influence the fire performance of composite frames

How bracing and heating regimes influence the fire performance of composite frames

On the fire performance of unbraced composite frames

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