Experimental Tests on Extended End-Plate Connections with Variable Parameters

Mahmood Md Tahir1,Md Azman Hussein 한국강구조학회 2008 International Journal of Steel Structures Vol.8 No.4

Typically, steel frames are designed either using the approach of pin joint for simple construction or rigid joint for continuous construction. However, in actual situation most of connections are classified as semi-rigid joint or partial strength which has been recognised and encouraged by Eurocode 3 in semi-continuous construction. Eight experimental tests have been carried out for extended end-plate connections consist of variable parameters such as size and thickness of end-plate, size and number of bolts, size of columns, and beams. The tests were set-up using local hot-rolled steel sections known as Perwaja sections for both beams and columns instead of typical British sections. Geometric parameters such as the thickness of end-plate, the number and size of bolts and the use of deeper beam have contributed significantly to the increase in moment resistance and stiffness of the connections. The study concluded that all the tested extended end-plate connections are eligible to be classified as partial strength connections and the results of maximum moment resistance showed good agreement between experimental and predicted component method in most cases.

Limiting the sway on multi-storey un-braced steel frames bending on weak axis with partial strength connections

Tahir, Mahmood Md.,Ngian, Poi Shek Techno-Press 2011 Structural Engineering and Mechanics, An Int'l Jou Vol.38 No.6

This paper investigates the design using wind-moment method for semi-rigid un-braced steel frames bending on weak axis. A limiting sway method has been proposed to reduce the frame sway. Allowance for steel section optimization between moment of inertia on minor axis column and major axis beam was used in conjunction with slope-deflection analysis to derive equations for optimum design in the proposed method. A series of un-braced steel frames comprised of two, four, and six bays ranging in height of two and four storey were studied on minor axis framing. The frames were designed for minimum gravity load in conjunction with maximum wind load and vice-versa. The accuracy of the design equation was found to be in good agreement with linear elastic computer analysis up to second order analysis. The study concluded that the adoption of wind-moment method and the proposed limiting sway method for semi-rigid steel frame bending on weak axis should be restricted to low-rise frames not more than four storey.

Comparison of Component Method with Experimental Tests for Flush End-Plate Connections using Hot-Rolled Perwaja Steel Sections

Mahmood Md. Tahir,Mohd Azman Hussein,Arizu Sulaiman,Shahrin Mohamed 한국강구조학회 2009 International Journal of Steel Structures Vol.9 No.2

A component method has been introduced by Steel Construction Institute to predict the moment resistance of partial strength connection. The design philosophy is taken directly from Eurocode 3 with strength checks on bolts, welds, and steel which have been modified to comply with BS 5950-1:2000. The accuracy of the method however needs to be validated with the experimental tests especially for hot-rolled sections other than typical British Section (BS). Six experimental tests on beamto- column connections have been carried out for Flush End-Plate (FEP) connections consisting of variable parameters such as thickness of end-plate, size and number of bolts, size of columns, and beams. The tests were set-up using local hot-rolled steel sections known as Perwaja Section (PS) for beams and columns instead of typical British Section (BS). The strength of materials for end-plate, column and beam sections were tested for tensile strength and used in predicting the moment resistance for component method. The moment versus rotation of the test results were plotted and compared with the moment resistance derived from component method. The study concluded that the moment resistance of the tested flush end-plate connections was higher than the predicted moment resistance from component method which showed good agreement between the two moments. The study also concluded that the tested FEP connections met the requirements and criteria of partial strength connections. A component method has been introduced by Steel Construction Institute to predict the moment resistance of partial strength connection. The design philosophy is taken directly from Eurocode 3 with strength checks on bolts, welds, and steel which have been modified to comply with BS 5950-1:2000. The accuracy of the method however needs to be validated with the experimental tests especially for hot-rolled sections other than typical British Section (BS). Six experimental tests on beamto- column connections have been carried out for Flush End-Plate (FEP) connections consisting of variable parameters such as thickness of end-plate, size and number of bolts, size of columns, and beams. The tests were set-up using local hot-rolled steel sections known as Perwaja Section (PS) for beams and columns instead of typical British Section (BS). The strength of materials for end-plate, column and beam sections were tested for tensile strength and used in predicting the moment resistance for component method. The moment versus rotation of the test results were plotted and compared with the moment resistance derived from component method. The study concluded that the moment resistance of the tested flush end-plate connections was higher than the predicted moment resistance from component method which showed good agreement between the two moments. The study also concluded that the tested FEP connections met the requirements and criteria of partial strength connections.

Experimental Tests on Composite and Non-composite Connections Using Trapezoid Web Profiled Steel Sections

Mahmood Md Tahir,Sulaiman A,Anis S 한국강구조학회 2008 International Journal of Steel Structures Vol.8 No.1

The use of partial strength or semi-rigid connections has been encouraged by Eurocode 3 and studies on the mater knownas semi-continuous construction have proven that substantial savings in steel weight of the overall construction. The objectiveof this paper is to present the performance of the strength, the rotational stifness, and the ductility of the composite connectionsand non-composite conection using trapezoidal web profiled steel (TWP) sections. Eight full scales testing of beam-to-columnconfigurations have ben carried out. The tests results showed good agreement betwen the experimental and the predictedvalues. The test also concluded that composite connections have higher moment resistance, higher stiffness, and less ductilecompared with the non-composite connections. The size of TWP steel section should be limited to 50m deep for bothcomposite and non-composite connections.

Limiting the sway on multi-storey un-braced steel frames bending on weak axis with partial strength connections

Mahmood Md. Tahir,Shek Poi Ngian 국제구조공학회 2011 Structural Engineering and Mechanics, An Int'l Jou Vol.38 No.6

This paper investigates the design using wind-moment method for semi-rigid un-braced steel frames bending on weak axis. A limiting sway method has been proposed to reduce the frame sway. Allowance for steel section optimization between moment of inertia on minor axis column and major axis beam was used in conjunction with slope-deflection analysis to derive equations for optimum design in the proposed method. A series of un-braced steel frames comprised of two, four, and six bays ranging in height of two and four storey were studied on minor axis framing. The frames were designed for minimum gravity load in conjunction with maximum wind load and vice-versa. The accuracy of the design equation was found to be in good agreement with linear elastic computer analysis up to second order analysis. The study concluded that the adoption of wind-moment method and the proposed limiting sway method for semi-rigid steel frame bending on weak axis should be restricted to low-rise frames not more than four storey.

Finite Element Analysis of Flush End-plate Connections Connected to Column Web

Mahmood Md Tahir,Irwan Juki,Lee Hong Yong,Shahrin Mohammad,Shek Poi Ngian 한국강구조학회 2011 International Journal of Steel Structures Vol.11 No.3

Eurocode 3: Part 1.8 (2005b) does not cover the empirical design for flush end-plate connections connected to column web. Thus, experimental works need to be performed to investigate the behaviour of the minor axis end-plate bolted connection. However, the experimental tests are expensive, tedious and time consuming to be conducted. Alternatively, finite element modelling and analysis can be adopted to predict the behaviour of the connection accurately. Five specimens of flush end-plate connections connected to column web with variable parameters have been tested and the results are compared with finite element analysis. Finite element models with enhanced strain solid and contact joint elements are used to stimulate the connection behaviour. The objective of this paper is to compare and validate the accuracy and reliability of the finite element model by correlating moment rotation (M-Φ) curves between the finite element model and experimental tests. The comparison shows a reasonable agreement between the predicted results from FEA and the experimental tests.

A numerical analysis on the performance of buckling restrained braces at fire-study of the gap filler effect

Elnaz Talebi,Mahmood Md Tahir,Farshad Zahmatkesh,Ahmad B.H. Kueh 국제구조공학회 2015 Steel and Composite Structures, An International J Vol.19 No.3

Buckling Restrained Braces (BRB) have been widely used in the construction industry as they utilize the most desirable properties of both constituent materials, i.e., steel and concrete. They present excellent structural qualities such as high load bearing capacity, ductility, energy-absorption capability and good structural fire behaviour. The effects of size and type of filler material in the existed gap at the steel core-concrete interface as well as the element's cross sectional shape, on BRB's fire resistance capacity was investigated in this paper. A nonlinear sequentially-coupled thermal-stress three-dimensional model was presented and validated by experimental results. Variation of the samples was described by three groups containing, the steel cores with the same cross section areas and equal yield strength but different materials (metal and concrete) and sizes for the gap. Responses in terms of temperature distribution, critical temperature, heating elapsed time and contraction level of BRB element were examined. The study showed that the superior fire performance of BRB was obtained by altering the filler material in the gap from metal to concrete as well as by increasing the size of the gap. Also, cylindrical BRB performed better under fire conditions compared to the rectangular cross section.

Wind-Moment Design of Semi-Rigid Un-braced Steel Frames using Cruciform Column (CCUB) Section

Shek Poi Ngian,Mahmood Md Tahir,Arizu Sulaiman,Tan Cher Siang 한국강구조학회 2015 International Journal of Steel Structures Vol.15 No.1

The design of un-braced frames using wind-moment method (WMM) with cruciform column (CCUB) section as verticalmember is presented here. Steel frames on a regular grid with approximately equal column spacings in the y-y and z-z directionusing UC/UB sections has resulted in minor axis controlled the design, which leads to a significant loss in performance. Theuse of CCUB sections with equal Iy and Iz warrants an equal behaviour in both directions whilst ensuring that both the majorand minor axis beam to column connections remain straightforward. The study has been conducted on 2-bay and 4-bay planeframes with 2, 4, 6 and 8 storey heights, and two different load cases are considered: minimum wind load in conjunction withmaximum gravity load and vice versa. Structural design optimization of steel frames was conducted on the selection of steelsections for beam and column. The selection was carried out in such a way that the steel frame had the minimum weight whilethe performance of the structure was within the limitations described by BS EN 1993-1-1: 2005. Significant column weightsavings (between 17-66%) was achieved by using CCUB section in the design, as compared to conventional UC sections.

Seismic and progressive collapse assessment of SidePlate moment connection system

Faridmehr, Iman,Osman, Mohd Hanim,Tahir, Mahmood Bin Md.,Nejad, Ali Farokhi,Hodjati, Reza Techno-Press 2015 Structural Engineering and Mechanics, An Int'l Jou Vol.54 No.1

The performance of a newly generated steel connection known as SidePlateTM moment connection for seismic loading and progressive collapse phenomenon has been investigated in this paper. The seismic evaluation portion of the study included a thorough study on of interstory drift angles and flexural strengths based on 2010 AISC Seismic Provisions while the acceptance criteria provided in UFC 4-023-03 guideline to resist progressive collapse must be satisfied by the rotational capacity of the connections. The results showed that the SidePlate moment connection was capable of attaining adequate rotational capacity and developing full inelastic capacity of the connecting beam. Moreover, the proposed connection demonstrated an exceptional performance for keeping away the plastic hinges from the connection and exceeding interstory drift angle of 0.06 rad with no fracture developments in beam flange groove-welded joints. The test results indicated that this type of connection had strength, stiffness and ductility to be categorized as a rigid, full-strength and ductile connection.

Seismic assessment of base-isolated nuclear power plants

Farmanbordar, Babak,Adnan, Azlan Bin,Tahir, Mahmood Md.,Faridmehr, Iman Techno-Press 2017 Advances in computational design Vol.2 No.3

This research presented a numerical and experimental study on the seismic performance of first-generation base-isolated and fixed-base nuclear power plants (NPP). Three types of the base isolation system were applied to rehabilitate the first-generation nuclear power plants: frictional pendulum (FP), high-damping rubber (HDR) and lead-rubber (LR) base isolation. Also, an Excel program was proposed for the design of the abovementioned base isolators in accordance with UBC 97 and the Japan Society of Base Isolation Regulation. The seismic assessment was performed using the pushover and nonlinear time history analysis methods in accordance with the FEMA 356 regulation. To validate the adequacy of the proposed design procedure, two small-scale NPPs were constructed at Universiti Teknologi Malaysia's structural laboratory and subjected to a pushover test for two different base conditions, fixed and HDR-isolated base. The results showed that base-isolated structures achieved adequate seismic performance compared with the fixed-base one, and all three isolators led to a significant reduction in the containment's tension, overturning moment and base shear.