Semi-rigid Composite Beam-to-column Joints for Cold-formed Steel Frames: Experimental and Numerical Study

Faisal Amsyar,Cher Siang Tan,Arizu Sulaiman,Shahrin Mohammad 한국강구조학회 2023 International Journal of Steel Structures Vol.23 No.4

An experimental and numerical study was performed to evaluate the structural behaviour of the semi-rigid composite cold-formed steel beam-to-column joints, in terms of its strength and stiffness. Five composite joints were subjected to different diameters of rebar (8 mm and 10 mm) with varying types of reinforcing bar (high-strength rebar, mild-strength rebar and high-strength steel wire mesh) and different thicknesses of concrete slab (100 mm and 125 mm). Isolated joint tests were dispensed to all specimens by using 100 kN capacity of hydraulic jack to induce axial point load. Non-linear finite element models were developed by using ABAQUS software for the joint configurations. A 3-D stress option with an eight-node linear brick element and no hourglass controls (C3D8) was proposed to simulate all steel and concrete components as it provided well analysis prediction with further simulation beyond ultimate load-bearing capacity. Good correlation was observed from comparison of both experimental and numerical results with strength ratios that ranged from 0.92 to 0.98. Ultimate strength was obtained by increasing the diameter of steel reinforcement, thickness of concrete slab and using high-strength steel reinforcing bar instead of mild-steel reinforcing bar and high-strength steel wire mesh.

Strength and Toughness of Lightweight Foamed Concrete with Different Sand Grading

Siong Kang Lim,Cher Siang Tan,Xiao Zhao,Tung Chai Ling 대한토목학회 2015 KSCE JOURNAL OF CIVIL ENGINEERING Vol.19 No.7

Lightweight Foamed Concrete (LFC) is one of the recent advancement of concrete technology in civil engineering. Different gradation of sand in lightweight foamed concrete will change the physical properties of the concrete. This paper aims to study the fresh and hardened properties of lightweight foamed concrete with density of 1300 ± 50 kg/ m3 that produced by using different gradations of sand. Four categories of sand gradations, ranging from 2.36 mm to 0.60 mm were used. Cube and prism specimens were cast and cured in water curing as well as 7-day initial water curing followed by air curing conditions. The measured spread values indicated that the finer sand used in the foamed concrete has lowered its workability and increases its water to cement ratio for desired consistency and stability. It was noted that the specimens prepared with 0.60 mm sand have obtained the highest compressive and flexural strengths as well as flexural toughness compared with the specimens prepared with coarser sand gradations.

Experimental Analysis of Cold-Formed Steel C-Sections with the Notch Subjected to Axial Compression

Mohd Syahrul Hisyam Mohd Sani,Fadhluhartini Muftah,Cher Siang Tan 대한토목학회 2020 KSCE JOURNAL OF CIVIL ENGINEERING Vol.24 No.4

Studies on the use of cold-formed steel (CFS) C-section, which is a civil engineering material, in building and civil engineering work are still on-going. The advantages of the CFS C-section are becoming so interesting that it is often being used as a roof truss system, storage rack, and wall framing. In order to have a roof truss system with a strong, safe, and stable condition, a study on truss member was carried out using the cut-curving process. Before the CFS C-section was curved, the process started by cutting the section in a proper way. A parametric study was conducted to determine the suitability of the cut pattern which recognised as a notch in the section and find out whether or not the notch depth would affect the ultimate load of the CFS C-section column. The study of CFS C-section was separated into two parts; firstly, to investigate the mechanical behaviour of the column in different notch depths and secondly, to investigate the behaviour in different column height with fixed notch depth. The notch width of 3 mm and notch spacing of 100 mm for both parts were fixed. Total specimen for both parts were 15 specimens. The results of the study showed that the reduction of the ultimate load was about 56 – 65% of the variation of notch depth section when compared with the normal section. Therefore, the ultimate load of the section with the notch decreased when the notch depth increased. In addition, the study illustrated that the reduction of the ultimate load was 64 – 82% of the variation of column height between 100 mm to 500 mm. Finally, the average percentage of the column height was 72% which can use in the modification of CFS C-section without notch to CFS C-section with notch calculation.

Flexural Behaviour of Reinforced Lightweight Foamed Mortar Beams and Slabs

Yee Ling Lee,Jee Hock Lim,Siong Kang Lim,Cher Siang Tan 대한토목학회 2018 KSCE JOURNAL OF CIVIL ENGINEERING Vol.22 No.8

This paper presents the experimental results on flexural behaviour of reinforced concrete beams and slabs made of lightweightfoamed mortar with density ranged from 1700 to 1800 kg/m3. Beam specimens consist of seven lightweight foamed mortar beamsand three normal weight concrete beams acted as the control sample. Whereas, slab specimens contain two lightweight foamedmortar slabs and two normal weight concrete slabs. Four types of lightweight foamed mortar with different cement-sand ratios andwater-cement ratios designated as LW-1, LW-2, LW-3 and LW-4 were produced in order to achieve targeted compressive strength of20 MPa at 28 days for structural usage. The results showed that reinforced lightweight foamed mortar beams sustained about 8% to34% lower ultimate load as compared to normal weight reinforced concrete with same reinforcement configuration. However,lightweight foamed mortar slab sustained higher ultimate load, averagely 18% as compared to normal weight slab. Apart from that, itwas observed that the both reinforced lightweight foamed mortar beams and slabs were weak in resisting shear forces nonethelessflexural failure cannot be ignored entirely due to the presence of excessive yielding of the steel strain data.

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.

Effect of Stressed-skin Action on Optimal Design of Cold-formed Steel Square And Rectangular-shaped Portal Frame Buildings

Andrzej M. Wrzesien,Duoc T. Phan,James B.P. Lim,Hieng-Ho Lau,Iman Hajirasouliha,Cher Siang Tan 한국강구조학회 2016 International Journal of Steel Structures Vol.16 No.2

Cold-formed steel (CFS) portal frames can be a viable alternative to conventional hot-rolled steel portal frames. They are commonly used for low-rise commercial, light industrial and agricultural buildings. In this paper, the effect of stressed-skin action on the optimum design of CFS portal frames is investigated by conducting a minimum cost design optimisation on a building of span of 6 m, height-to-eaves of 3 m and frame spacing of 3 m; the effect of different number of bays are considered. For the purpose of this study, it is assumed that gables are rigid.The effect of stressed-skin action is larger for“square-shaped” buildings (i.e. when the span and length are the same on plan) and decreases as more bays are added(i.e. as the building becomes more “rectangular-shaped” on plan). The results of the minimum cost optimisation indicate that if stressed-skin action is taken into account, the cost of the internal frame can be reduced by around half for “square-shaped” buildings. It should be noted that this is a minimum cost optimisation, which is not the same as a minimum weight optimisation. It is also shown that a safe design of internal frames could be obtained by ignoring wind loads (i.e. designing the frame only for gravity loads),but this is limited to buildings having a “square-shape”.