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Article
Publication date: 14 March 2016

Pedro Palma, Andrea Frangi, Erich Hugi, Paulo Cachim and Helena Cruz

This paper aims to present the results of an extensive experimental programme on the fire behaviour of timber beam-to-column shear connections, loaded perpendicularly to the grain.

Abstract

Purpose

This paper aims to present the results of an extensive experimental programme on the fire behaviour of timber beam-to-column shear connections, loaded perpendicularly to the grain.

Design/methodology/approach

The experimental programme comprised tests at normal temperature and loaded fire resistance tests on beam-to-column connections in shear. Twenty-four full-scale tests at normal temperature were performed covering nine different connection typologies, and 19 loaded fire resistance tests were conducted including 11 connections typologies.

Findings

The results of the fire resistance tests show that the tested typologies of steel-to-timber dowelled connections reached more than 30 and even 60 minutes of fire resistance. However, aspects such as a wider gap between the beam and the column, reduced dowel spacing, and the presence of reinforcement with self-drilling screws all have a negative influence on the fire resistance.

Originality/value

The experimental programme addressed the fire behaviour of timber beam-to-column shear connections loaded perpendicularly to the grain in a systematic way testing a wide range of common connection typologies significantly enlarging their experimental background.

Details

Journal of Structural Fire Engineering, vol. 7 no. 1
Type: Research Article
ISSN: 2040-2317

Keywords

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Article
Publication date: 13 June 2016

Xuhong Qiang, Xu Jiang, Frans Bijlaard and Henk Kolstein

This paper aims to investigate and assess a perspective of combining high-strength-steel endplate with mild-steel beam and column in endplate connections.

Abstract

Purpose

This paper aims to investigate and assess a perspective of combining high-strength-steel endplate with mild-steel beam and column in endplate connections.

Design/methodology/approach

First, experimental tests on high strength steel endplate connections were conducted at fire temperature 550°C and at an ambient temperature for reference.

Findings

The moment-rotation characteristic, rotation capacity and failure mode of high-strength-steel endplate connections in fire and at an ambient temperature were obtained through tests and compared with those of mild-steel endplate connections. Further, the provisions of Eurocode 3 were validated with test results. Moreover, the numerical study was carried out via ABAQUS and verified against the experimental results.

Originality/value

It is found that a thinner high-strength-steel endplate can enhance the connection’s rotation capacity both at an ambient temperature and in fire (which guarantees the safety of an entire structure) and simultaneously achieve almost the same moment resistance with a mild steel endplate connection.

Details

Journal of Structural Fire Engineering, vol. 7 no. 2
Type: Research Article
ISSN: 2040-2317

Keywords

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Article
Publication date: 30 September 2019

Adam Roman Petrycki and Osama (Sam) Salem

In fire condition, the time to failure of a timber connection is mainly reliant on the wood charring rate, the strength of the residual wood section, and the limiting…

Abstract

Purpose

In fire condition, the time to failure of a timber connection is mainly reliant on the wood charring rate, the strength of the residual wood section, and the limiting temperature of the steel connectors involved in the connection. The purpose of this study is to experimentally investigate the effects of loaded bolt end distance, number of bolt rows, and the existence of perpendicular-to-wood grain reinforcement on the structural fire behavior of semi-rigid glued-laminated timber (glulam) beam-to-column connections that used steel bolts and concealed steel plate connectors.

Design/methodology/approach

In total, 16 beam-to-column connections, which were fabricated in wood-steel-wood bolted connection configurations, in eight large-scale sub-frame test assemblies were exposed to elevated temperatures that followed CAN/ULC-S101 standard time-temperature curve, while being subjected to monotonic loading. The beam-to-column connections of four of the eight test assemblies were reinforced perpendicular to the wood grain using self-tapping screws (STS). Fire tests were terminated upon achieving the failure criterion, which predominantly was dependent on the connection’s maximum allowed rotation.

Findings

Experimental results revealed that increasing the number of bolt rows from two to three, each of two bolts, increased the connection’s time to failure by a greater time increment than that achieved by increasing the bolt end distance from four- to five-times the bolt diameter. Also, the use of STS reinforcement increased the connection’s time to failure by greater time increments than those achieved by increasing the number of bolt rows or the bolt end distance.

Originality/value

The invaluable experimental data obtained from this study can be effectively used to provide insight and better understanding on how mass-timber glulam bolted connections can behave in fire condition. This can also help in further improving the existing design guidelines for mass-timber structures. Currently, beam-to-column wood connections are designed mainly as axially loaded connections with no guidelines available for determining the fire resistance of timber connections exerting any degree of moment-resisting capability.

Details

Journal of Structural Fire Engineering, vol. ahead-of-print no. ahead-of-print
Type: Research Article
ISSN: 2040-2317

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Article
Publication date: 29 March 2018

Osama (Sam) Salem

In fire condition, the limiting temperature of a restrained steel beam depends on a few parameters, e.g. temperature distributions along and across the beam, beam’s load…

Abstract

Purpose

In fire condition, the limiting temperature of a restrained steel beam depends on a few parameters, e.g. temperature distributions along and across the beam, beam’s load ratio and span length. The purpose of this study is to investigate the structural fire behaviour of axially restrained steel beams under different beam’s load ratios, taking into consideration the effect of the beam’s end connections configuration.

Design/methodology/approach

A three-dimensional finite element (FE) computer model has been developed to simulate the structural fire behaviour of axially restrained steel beams and their end connections. After successfully validating the developed model against the outcomes of the available large-size fire resistance experiments, the FE model has been used in a parametric study to investigate the beam’s load ratio effect on the behaviour of the axially restrained steel beams and their end connections.

Findings

The parametric study showed that increasing the beam loading level significantly increased the beam deflections at elevated temperatures; where, increasing the beam’s load ratio from 0.5 to 0.9 reduced the beam fire resistance by about 100 s. In contrast, decreasing the beam’s load ratio from 0.5 to 0.3 allowed the beam to easily achieve a 30-min fire resistance rating with no fire protection applied.

Originality/value

Experimental parametric studies are difficult to control in a laboratory setting and are also expensive and time consuming. Therefore, the reasonable accuracy of the validated FE model in reproducing the experimental fire behaviour of steel beams and their end connections makes it a very useful tool for both numerical and analytical studies.

Details

Journal of Structural Fire Engineering, vol. 9 no. 4
Type: Research Article
ISSN: 2040-2317

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Article
Publication date: 12 June 2017

Xuhong Qiang, Nianduo Wu, Xu Jiang, Frans Bijlaard and Henk Kolstein

This study aims to reveal more information and understanding on performance and failure mechanisms of high strength steel endplate connections after fire.

Abstract

Purpose

This study aims to reveal more information and understanding on performance and failure mechanisms of high strength steel endplate connections after fire.

Design/methodology/approach

An experimental and numerical study on seven endplate connections after cooling down from fire temperature of 550°C has been carried out and reported herein. Moreover, the provisions of European design standard for steel structures, Eurocode 3, were validated with test results of high strength steel endplate connections.

Findings

In endplate connections, a proper design using a thinner high strength steel endplate can achieve the same failure mode, similar residual load bearing capacity and comparable or even higher rotation capacity after cooling down from fire. It is found that high strength steel endplate connection can regain more than 90 per cent of its original load bearing capacity after cooling down from fire temperature of 550°C.

Originality/value

The post-fire performance of high strength steel endplate connection has been reported. The accuracy of Eurocode 3 for endplate connections is validated against test results.

Details

Journal of Structural Fire Engineering, vol. 8 no. 2
Type: Research Article
ISSN: 2040-2317

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Article
Publication date: 1 January 1986

Ray Denenberg

Vendors who are implementing the Standard Network Interconnection (SNI) protocols for computer to computer communications can now test their implementation against the…

Abstract

Vendors who are implementing the Standard Network Interconnection (SNI) protocols for computer to computer communications can now test their implementation against the LSP/SNI Test Facility, which has been developed by the Library of Congress. The facility is intended to verify the correct functioning of the SNI protocols for the Open System Interconnection (OSI) layers. The development and use of the Test Facility are discussed.

Details

Library Hi Tech, vol. 4 no. 1
Type: Research Article
ISSN: 0737-8831

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Article
Publication date: 14 July 2017

Amir Saedi Daryan and Mahmood Yahyai

This paper aims to predicting the behavior of welded angle connections (moment-rotation-temperature) in fire using artificial neural network 10.

Abstract

Purpose

This paper aims to predicting the behavior of welded angle connections (moment-rotation-temperature) in fire using artificial neural network 10.

Design/methodology/approach

An artificial neural networking model is described to predict the moment-rotation response of semi-rigid beam-to-column joints at elevated temperature.

Findings

Data from 47 experimental fire tests and verified finite element model are used for training and testing and validating the neural network models. The model’s predicted values are compared with actual test results. The results indicate that the models can predict the moment-rotation-temperature behavior of semi-rigid beam-to-column joints with very high accuracy. The developed model can be modified easily to investigate other parameters that influence the performance of joints in fire.

Originality/value

The results indicate that the models can predict the moment-rotation-temperature behavior of semi-rigid beam-to-column joints with very high accuracy. The developed model can be modified easily to investigate other parameters that influence the performance of joints in fire.

Details

Journal of Structural Fire Engineering, vol. 9 no. 1
Type: Research Article
ISSN: 2040-2317

Keywords

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Article
Publication date: 17 June 2014

Dhionis Dhima, Maxime Audebert and Abdelhamid Bouchaïr

Two different configurations of steel-to-timber connections are tested in bending in normal conditions and under ISO-fire exposure. To observe the influence of clearances…

Abstract

Two different configurations of steel-to-timber connections are tested in bending in normal conditions and under ISO-fire exposure. To observe the influence of clearances in the connection area on the fire resistance of the connections, two specimens were previously tested under cyclic loadings. These tests consist in the application of loading-unloading cycles by controlled displacements. The experimental results of connections tested in cold and under ISO-fire conditions are analyzed and commented. These results are then used to validate a finite element model. This model allows to simulate numerically the evolution of the temperatures inside the connections as well as their mechanical and thermo-mechanical behaviours. The thermal modelling is validated on the basis of the temperature-time evolutions measured during fire tests. The nonlinear modelling of the mechanical behaviour of timber is done using the Hill yield criterion in combination with the Tsaï-Wu failure criterion. The thermo-mechanical modelling allows obtaining fire resistances of the tested connections in good agreement with the experimental ones.

Details

Journal of Structural Fire Engineering, vol. 5 no. 2
Type: Research Article
ISSN: 2040-2317

Keywords

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Article
Publication date: 9 March 2015

Ahmed Ahmim and Nacira Ghoualmi Zine

The purpose of this paper is to build a new hierarchical intrusion detection system (IDS) based on a binary tree of different types of classifiers. The proposed IDS model…

Abstract

Purpose

The purpose of this paper is to build a new hierarchical intrusion detection system (IDS) based on a binary tree of different types of classifiers. The proposed IDS model must possess the following characteristics: combine a high detection rate and a low false alarm rate, and classify any connection in a specific category of network connection.

Design/methodology/approach

To build the binary tree, the authors cluster the different categories of network connections hierarchically based on the proportion of false-positives and false-negatives generated between each of the two categories. The built model is a binary tree with multi-levels. At first, the authors use the best classifier in the classification of the network connections in category A and category G2 that clusters the rest of the categories. Then, in the second level, they use the best classifier in the classification of G2 network connections in category B and category G3 that represents the different categories clustered in G2 without category B. This process is repeated until the last two categories of network connections. Note that one of these categories represents the normal connection, and the rest represent the different types of abnormal connections.

Findings

The experimentation on the labeled data set for flow-based intrusion detection, NSL-KDD and KDD’99 shows the high performance of the authors' model compared to the results obtained by some well-known classifiers and recent IDS models. The experiments’ results show that the authors' model gives a low false alarm rate and the highest detection rate. Moreover, the model is more accurate than some well-known classifiers like SVM, C4.5 decision tree, MLP neural network and naïve Bayes with accuracy equal to 83.26 per cent on NSL-KDD and equal to 99.92 per cent on the labeled data set for flow-based intrusion detection. As well, it is more accurate than the best of related works and recent IDS models with accuracy equal to 95.72 per cent on KDD’99.

Originality/value

This paper proposes a novel hierarchical IDS based on a binary tree of classifiers, where different types of classifiers are used to create a high-performance model. Therefore, it confirms the capacity of the hierarchical model to combine a high detection rate and a low false alarm rate.

Details

Information & Computer Security, vol. 23 no. 1
Type: Research Article
ISSN: 2056-4961

Keywords

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Article
Publication date: 13 June 2016

Veronika Hofmann, Martin Gräfe, Norman Werther and Stefan Winter

This paper deals with the fire resistance of primary and secondary beam connections in timber structures.

Abstract

Purpose

This paper deals with the fire resistance of primary and secondary beam connections in timber structures.

Design/methodology/approach

This paper describes a series of unloaded and loaded furnace fire tests in different configurations of these types of connectors.

Findings

The main objective is the fire safety design of joist hangers and full thread screws.

Originality/value

Design recommendations are given.

Details

Journal of Structural Fire Engineering, vol. 7 no. 2
Type: Research Article
ISSN: 2040-2317

Keywords

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