Modelling of beam-to-column connections at elevated temperature using the component method

N.H. Ramli Sulong,A.Y. Elghazouli,B.A. Izzuddin,N. Ajit 국제구조공학회 2010 Steel and Composite Structures, An International J Vol.10 No.1

In this paper, a nonlinear model is developed using the component method in order to represent the response of steel connections under various loading conditions and temperature variations. The model is capable of depicting the behaviour of a number of typical connection types including endplate forms (extended and flush) and angle configurations (double web, top and seat, and combined top-seat-web) in both steel and composite framed structures. The implementation is undertaken within the finite element program ADAPTIC, which accounts for material and geometric nonlinearities. Verification of the proposed connection model is carried out by comparing analytical simulations with available results of isolated joint tests for the ambient case, and isolated joint as well as sub-frame tests for elevated temperature conditions. The findings illustrate the reliability and efficiency of the proposed model in capturing the stiffness and strength properties of connections, hence highlighting the adequacy of the component approach in simulating the overall joint behaviour at elevated temperature.

Bolted connections to tubular columns at ambient and elevated temperatures - A review

N.H. Ramli Sulong,S.H. Leong,Mohammed Jameel 국제구조공학회 2016 Steel and Composite Structures, An International J Vol.21 No.2

Tubular column members have been widely adopted in current construction due to its numerous advantages. However, the closed-section profile characteristics of tubular columns severely limit the connection possibilities. Welding type is acceptable but discouraged because of on-site issues. Blind-bolted connection is preferable because of its simplicity, economic benefit, and easy assembly. This paper presents a state-of-the-art review on bolted connections to tubular columns for bare steel tubes, including square and circular sections. Available studies on bolted connections at ambient and elevated temperatures are reviewed, but emphasis is given on the latter. Various methods of determining the connection performance through experimental, analytical, component based, and finite element approaches are examined. Future research areas are also identified.

Characterizing the Cyclic Behavior of Stiffened SPSWs

O. Haddad,N.H. Ramli Sulong,Z. Ibrahim 대한토목학회 2019 KSCE JOURNAL OF CIVIL ENGINEERING Vol.23 No.4

To enhance the behavior of steel plate shear walls, stiffeners are attached on the infill plate. The various researches on the stiffened Steel Plate Shear Walls (SPSWs) with Low Yield Point (LYP) infill steel plate have approved excellent capacity of this system. In those studies, the researcher focused on the specific type on stiffeners and in some cases, different results was reported. To cover different aspects, to provide comprehensive necessary data for structure designers and, to study the post-buckling and performance factors, this research is conducted. Using the validated Finite Element (FE) models with experimental test results, an analytical study of a single story SPSWs conducted to determine the influence of the selected parameters on the strength, stiffness, energy absorption and seismic performance factors. The variant parameters include the stiffeners pattern, stiffeners thickness, one-side or double-sides stiffeners and the slenderness of the stiffened infill plates. The results showed that cross-stiffened pattern is preferable in the one-side stiffening method while, diagonal pattern in double-side shape. Finally, the value of seismic performance factors is proposed for stiffened SPSWs.

Effect of Axial Restraints on Top-Seat Angle Connections at Elevated Temperatures

Leong Siong Hean,N.H. Ramli Sulong,Mohammed Jameel 대한토목학회 2016 KSCE Journal of Civil Engineering Vol.20 No.6

In this study, a finite element model of a top-seat angle connection at elevated temperature is developed to study the effect of axial restraints on the connection behavior. Models are first validated with existing fire test results of top-seat angle connection. Non-linear behavior of the materials was modeled with the definition of elastic-plastic multi-linear properties and frictional contact between surfaces is included to simulate actual conditions. Validation of the model behavior shows that the model is in good agreement with existing experimental results and therefore the model is used for further study on the effect of axial restraints towards connection behavior. Both isothermal and anisothermal conditions were analyzed considering the effect of axial restraints. Results from the model shows that an increase in axial restraints has increased connection capacity while the stiffness remains similar for low axial levels. On the other hand, the shrinkage of the beam, may lead to tensional axial loads, causing axial pulling on the connection, resulting in higher deformation and different deformation patterns of the component angle sections. Effect on the design guidelines for connection design with axial restraints provided by Eurocode 3:2005 (Part 1-8) is also discussed at the end.

Modelling of beam-to-column connections at elevated temperature using the component method

B.A. Izzuddin,N.H. Ramli Sulong,A.Y. Elghazouli,N. Ajit 국제구조공학회 2006 Steel and Composite Structures, An International J Vol.6 No.1

In this paper, a nonlinear model is developed using the component method in order to represent the response of steel connections under various loading conditions and temperature variations. The model is capable of depicting the behaviour of a number of typical connection types including endplate forms (extended and flush) and angle configurations (double web, top and seat, and combined top-seat-web) in both steel and composite framed structures. The implementation is undertaken within the finite element program ADAPTIC, which accounts for material and geometric nonlinearities. Verification of the proposed connection model is carried out by comparing analytical simulations with available results of isolated joint tests for the ambient case, and isolated joint as well as sub-frame tests for elevated temperature conditions. The findings illustrate the reliability and efficiency of the proposed model in capturing the stiffness and strength properties of connections, hence highlighting the adequacy of the component approach in simulating the overall joint behaviour at elevated temperature.

Performance of shear connectors at elevated temperatures − A review

S.E.M. Shahabi,N.H. Ramli Sulong,M. Shariati,S.N.R. Shah 국제구조공학회 2016 Steel and Composite Structures, An International J Vol.20 No.1

Shear connectors are key components to ensure the efficient composite action and satisfactory transfer of shear forces at the steel–concrete interface in composite beams. Under hazardous circumstances, such as fire in a building, the performance of a composite beam significantly relies on the performance of shear connectors. Studies on the behavior of shear connectors subjected to elevated temperatures performed in the last decade are reviewed in this paper. The experimental testing of push-out specimens, the design approaches provided by researchers and different codes, the major failure modes, and the finite element modeling of shear connectors are highlighted. The critical research review showed that the strength of a shear connector decreases proportionally with the increase in temperature. Compared with the volume of work published on shear connectors at ambient temperatures, a few studies on the behavior of shear connectors under fire have been conducted. Several areas where additional research is needed are also identified in this paper.

Numerical analysis of channel connectors under fire and a comparison of performance with different types of shear connectors subjected to fire

S.E.M. Shahabi,N.H. Ramli Sulong,M. Shariati,M. Mohammadhassani,S.N.R. Shah 국제구조공학회 2016 Steel and Composite Structures, An International J Vol.20 No.3

The behavior of shear connectors plays a significant role in maintaining the required strength of a composite beam in normal and hazardous conditions. Various types of shear connectors are available and being utilized in the construction industry according to their use. Channel connectors are a suitable replacement for conventional shear connectors. These connectors have been tested under different types of loading at ambient temperature; however, the behavior of these connectors at elevated temperatures has not been studied. This investigation proposes a numerical analysis approach to estimate the behavior of channel connectors under fire andcompare it with the numerical analysis performed in headed stud and Perfobond shear connectors subjected to fire. This paper first reviews the mechanism of various types of shear connectors and then proposes a non-linear thermomechanical finite element (FE) model of channel shear connectors embedded in high-strength concrete (HSC) subjected to fire. Initially, an accurate nonlinear FE model of the specimens tested at ambient temperature was developed to investigate the strength of the channel-type connectors embedded in an HSC slab. The outcomes were verified with the experimental study performed on the testing of channel connectors at ambient temperature by Shariati <i>et al</i>. (2012). The FE model at ambient temperature was extended to identify the behavior of channel connectors subjected to fire. A comparative study is performed to evaluate the performance of channel connectors against headed stud and Perfobond shear connectors. The channel connectors were found to be a more economical and easy-to-apply alternative to conventional shear connectors.

Experimental Investigation on Fatigue Behavior of Wide-Flange Steel I-Beams Strengthened Using Diff erent CFRP End Cutting Shapes

Mohamed Kamruzzaman,MohdZamin Jumaat,N.H. Ramli Sulong,Kambiz Narmashiri,Khaled Ghaedi,Md. Akter Hosen 한국강구조학회 2019 International Journal of Steel Structures Vol.19 No.3

In recent decades, the application of carbon fi bre-reinforced polymer (CFRP) composites for strengthening structural elements has become an effi cient option to meet the increased cyclic loads, or repair due to fatigue cracking. The premature failure due to end-debonding is a key limitation to achieve high fatigue performance of strengthened steel beams with externally bonded CFRP plates. The objective of this study is to explore the reinforcing techniques using the CFRP in-plane end cutting shapes and the triangular spew fi llet of adhesive at the tips of the plate to care for fatigue damaged of wide-fl ange steel I-beams due to end-debonding. Four in-plane CFRP end cutting shapes were chosen, namely: rectangular, semi-elliptical, semi-circular and trapezoidal. The application of the trapezoidal end shape was found to be the best confi guration for delaying the end-debonding failure mode and high fatigue life compared to the other CFRP in-plane end cutting shapes. Applying the triangular spew fi llets of adhesive signifi cantly increased the end-debonding and steel beam fracture initiation life of the strengthened beams.

Nonlinear Dynamic Response of Tension Leg Platform under Environmental Loads

M. Jameel,D. O. Oyejobi,N. A. Siddiqui,N.H. Ramli Sulong 대한토목학회 2017 KSCE JOURNAL OF CIVIL ENGINEERING Vol.21 No.3

This paper investigated the platform motion and tether tension of tension leg platform subjected to eight sea states ranging from extreme to moderate states. The mass, stiffness and damping force matrices were formulated for the platform and the tethers were considered as non-linear springs. The surface elevation and wave kinematics were calculated by small wave amplitude theory. On the other hand, the force vector was calculated by integrating over the entire length of the hull members using Morison equation. The various degree of non-linearity considered include the drag force, the variable added mass, large displacement as well as variations in tether tension. A finite element numerical research program was developed for solution of the nonlinear problem. The statistical response parameters for the degrees of freedom show that as we move towards the less severe sea states, all the responses were decreasing. Response comparison of one tether missing and an intact tendon of tension leg platform show an increase in surge and tether tension but heave response decreased due to reduction in stiffness against vertical movement. Dynamic analysis of the platform under the combined action of wave, current and wind is recommended so as to know true platform behaviours.