Vibration response of USFB composite floors

This paper is focused on the vibration response of a composite flooring system that incorporates perforated steel Ultra Shallow Floor Beams, called USFB. This is a lightweight system that can accommodate long spans; hence it is susceptible to floor vibrations excited by dynamic loads. Both experimental and computational proposed finite element (FE) studies have been conducted to investigate various geometric parameters following a comparative study on a flooring system with bare steel perforated USFBs. Emphasis was placed on the fundamental frequency to predict the possibility of resonance of this new breed of flooring systems

Assessment of beam-column connections using perforated beams with multiple closely spaced web openings

Recently researchers concentrate on alternative fuse designs promoting the concept of performance-based design while reducing the beam section in different ways including that of creating a hole in its web (RWS connections). Similar practice is applied in the fabrication of perforated beams mostly used to support the service integration as well as the significant mass reduction in steel frames. This paper presents a finite element (FE) analysis of a partially restrained extended end-plate connection with single and multiple circular web perforations introduced along the length of the beam and subjected to the cyclic loading proposed by SAC protocol from FEMA-350 (2000). The parameters introduced were the distance from the face of the column, S, and the number of closely spaced web openings. The design of such connections should be based on the articulate decision of the first opening’s distance from the face of the column

Optimised 3D Printed Metallic Node-Connections for Reticulated Structures

Structural Topology Optimisation (STO) is a prevalent optimisation technique used nowadays to reach highly complex and efficient designs (weight-to-stiffness ratio) unable to achieve otherwise. Additive Manufacturing (AM) is a developing manufacturing process which overcomes many of the manufacturing limitations and realises highly optimised products through a layer-based fabrication process. Recent research on reticulated structures proposed using STO and 3D printing to design and fabricate alternative bespoke complex connection designs which have shown their significance through obtaining substantial weight reductions for the same structural capacity. This paper builds on previous research through optimising a single-layer typical node-connection under four loading cases, producing a state-of-the-art optimised connection design capable of withstanding the four loading cases considered and comparing the results to the typical ones. In all loading cases, optimised shapes with 46.9% weight reduction were obtained with varying stress levels. A selection of the highly bespoke designs was 3D printed as a proof of concept for the applicability of AM

Derivation of dynamic properties of steel perforated ultra shallow floor beams (USFB) via finite element modal analysis and experimental verification

In recent years, the incorporation of asymmetric perforated ultra shallow floor beams (USFBs) constructed from advanced UB and UC profile beams in various composite floor systems has been extensively considered in practice. To date, limited research effort has been devoted to the detailed investigation of the dynamic properties of USFBs. In this paper, modal analyses of detailed FE models of various USFBs commonly used in composite floor systems developed in ANSYS are conducted to extract their dynamical properties (i.e. natural frequencies and mode shapes). Furthermore, experimental data pertaining to the standard impact test is also considered to validate the accuracy of the aforementioned FE results. In particular, a six meter long USFB beam is subject to impulsive excitation by means of an appropriately instrumented hammer. The dynamic properties obtained by processing the recorded response signals compare well vis-a-vis the corresponding results from the FE modal analysis. Finally, effective properties of USFBs which can be readily used in the definition of beam elements of constant cross-section along their longitudinal direction are derived. This constitutes an important step to facilitate the analysis and design of USFBs against dynamic loads at the serviceability limit state using standard commercial structural analysis software