Shahrin Mohammad

Review on Cold-Formed Steel Connections

The concept of cold-formed light steel framing construction has been widespread after understanding its structural characteristics with massive research works over the years. Connection serves as one of the important elements for light steel framing in order to achieve its structural stability. Compared to hot-rolled steel sections, cold-formed steel connections perform dissimilarity due to the thin-walled behaviour. This paper aims to review current researches on cold-formed steel connections, particularly for screw connections, storage rack connections, welded connections, and bolted connections. The performance of these connections in the design of cold-formed steel structures is discussed.

Numerical Modelling of Stiffness and Strength Behaviour of Top-Seat Flange-Cleat Connection for Cold-Formed Double Channel Section

Prediction of structural behaviour by numerical modelling can reduce the cost in conducting full-scaled experiments. This paper studies the stiffness and strength behaviour of top-seat flange-cleat connection for cold-formed steel double channel sections using finite element method. In this investigation, cold-formed channel sections are assembled back-to-back to form I-shape beam and column members. The 2 mm cold-formed bracket and 6 mm hot-rolled angle are used to connect the members. The results were collected from different beam depth ranged 150 mm, 200 mm and 250 mm. The rotational stiffness and strength obtained from the numerical modelling are then compared to the design requirements from BS EN 1993-1-8 and experimental data. The comparison of moment-rotation behaviour for top-seat flange-cleat connection has shown not more than 35% difference for strength behaviour and 50% difference for rotational stiffness behaviour between numerical modelling and experimental data. However, there is a noticeable difference between finite element models and analytical calculation. The differences are recorded from 18% to 65% for strength behaviour and between 1% and 153% for stiffness behaviour. The differences obtained between finite element analysis and experimental investigation are caused by edge stiffener while differences from finite element models and analytical models are due to strain hardening.

Engineering Education in Southeast Asia: Practice and Research

Engineering education is gaining interest among various stakeholders in many countries around the world especially in Southeast Asia. Many countries in this region have engineering education societies and accreditation bodies that promote quality engineering education, particularly in higher learning institutes. The demands of employable engineering graduates and the twenty-first-century grand challenges have forced more initiatives and attention towards research on the engineering education practices. Therefore, engineering education centers are established to carry out research, training, and services that can improve and enhance the practice. However, without the virtuous cycle of research, the initiatives to research the engineering education practice are not grounded to the related educational theories and cannot bridge the research findings to practice. This chapter provides an overview of the development of engineering education in Southeast Asia and proposes the virtuous cycle of research in bridging theories, research, and practice in engineering education.

Effective steel area of fully embedded cold-formed steel frame in composite slab system under pure bending

In conjunction with the promote of Industrial Building System (IBS) in Malaysia building construction, precast units such as slab, beam and column were widely used. This paper reports on the determination of the effective cross sectional area of the proposed cold-formed sections that embedded in precast concrete slab. The cold-formed steel sections are single and double lipped channel section, with 100mm in depth, 50 mm width, 12 mm lips length and 1.55 mm thickness. In order to determine the flexural capacity of the composite slab system, it is necessary to identify the effective cross sectional area of the section contributes to load-carrying of the slab system. The calculation method was based on the effective width method concept from BS EN 1993-1-3 and BS EN 1993-1-5. Four types of cold-formed steel frame profiles that embedded in the concrete to form a new type of composite slab system were used to study in this paper. The four types of cold-formed steel section configuration are S1-SV, S2-SH, S3-DV and S4-DH. From the analytical calculation, S3-DV has the highest effective cross-sectional area, which it only consists of 2% ineffective area for load-carry capacity. Besides that, single lipped section S2-SH fully utilized the cross sectional in carrying load. It can be concluded that S3-DV is predicted to have highest bending resistance than other three types of configuration with condition that the reliability of the prediction need to verify as other factors such as shear bonding and shifted neutral axis happened due to combination of concrete and cold-formed section which, will also contribute the strength capacity of the composite slab system.

Experimental Investigation of Cold-formed Steel (CFS) Channel Material at Post Elevated Temperature

Cold formed steel (CFS) is the popular structural material used in the building nowadays due to a variety of advantages in its manufacturing, fabrication and erection. The main objective of the study is to study the properties of the CFS at post elevated temperature. When this material is exposed to fire the steel material properties are degraded. Therefore, it is important to predict the degradation of material properties of CFS after exposed to elevated temperatures. The microstructure test was found that after exposing to 1,000 °C temperature compared to normal CFS, the composition of eight elements in CFS has increased as Carbon, C is the highest at 129.7 %, meanwhile, thirteen elements are decreasing as Silicon, Si is the highest at 80.6 %. Results from tensile coupon test of post elevated temperature CFS shows that the cold formed steel that expose to fire may regain its yield strength within 10–60 % for range temperature 400–1,000 °C when compared to the Class 4 steel in EC3-1-2. The pattern of the reduction factor of CFS is similar to the hot rolled steel S460.

Numerical Simulation for Predicting Fire Behavior of Axially Loaded Circular Concrete Filled Steel Tubular Columns

The present study investigates the behavior of axial loaded circular concrete filled hollow steel section (CFHSS) columns. A nonlinear finite element model using ABAQUS program was developed to investigate the fire behavior of the inspected columns from previous fire tests. The study variables include column dimensions, steel section wall thickness, concrete strength, concrete types (plain or reinforced), and fire protection thickness. The comparison indicated that the results obtained from the model were within acceptable limit of accuracy of 15%. A sensitivity study was carried out to investigate the influence of the output of the numerical model including the Poisson’s ratio of concrete, thermal conductance at the steel-concrete interface, frictional contact at steel-concrete interface, and imperfection buckling of columns. Based on the sensitivity analysis, several modelling suggestions were given in this paper which will be beneficial for further study.

Behavior of Boxed Cold-Formed Steel as Composite Beam with Rebar as Shear Connector

The use of composite systems comprising of concrete and conventional steel is commonly used in a multi-story steel frame with hot-rolled steel section. However, the use of cold-formed steel section designed as composite beam is yet to be established. Cold-formed steel (CFS) is usually categorized as a slender section which tends to buckle and deform. The strength of this section is usually reduced significantly as the section is very thin. However, all these problems can be significantly improved by designing the section as composite construction by integrating concrete and steel with the use of rebar as a shear connector. Therefore, this paper presents experimental works on the structural performance of cold-formed steel (CFS) section with self-compacting concrete (SCC) as a composite beam by means of the shear connection mechanism of the proposed using reinforcement bar. A specimen was carried out where the behavior of encased double cold-formed steel composite beam with composite slab was tested until failure. The proposed shear connector of size 12 mm was embedded in CFS and encased in SCC with a compressive strength of 40 N/mm2. The specimen comprised of two parallel CFS attached together to form encased beam with a concrete slab. Based on the experimental results it was found that the proposed composite system using bent-up rebar as shear connector showed slightly higher results than expected with ultimate moment capacity of 358.3 kNm for experimental and 341 kNm for predicted results. The failure mode was recorded as ductile which make it suitable to be used in the seismic zone.

Experimental investigation on box-up cold-formed steel columns in fire

Cold-formed steel is a popular material with various advantages. Its easy production and assembly give engineer an option to speed the construction process. However, thinness relates to the major issue of buckling, especially when dealing with high temperature. The unprotected cold-formed steel behaviour under fire is expected to have a little strength as compared to hot-rolled steel. Information on such behaviour is still limited. Fire resistance testing on built-up box CFS column was presented in this paper. Two fire resistance tests were carried out under compression load. The Standard ISO 834 Fire Resistance Test under 50% and 70% degree of utilisation measured the temperatures at several points of the steel column surface by using a surface thermocouple and axial column deformation. For reference purpose, one same static test at ambient temperature was carried out to assess the load bearing capacity. Results found that the failure temperature of built-up CFS could reach up to 515 °C and 443 °C within 8 minutes and 7 minutes resistant time for 50 % and 70% degree of utilisation, respectively. Based on deformation analysis, buckling temperature of the column was 448 °C and 394 °C with a critical time of 7 minutes for 50 % and 70% degree of utilisation, respectively. This concluded that the higher degree of utilisation results in lower critical temperatures of the columns.

Temperature development of cold formed steel column channel section under standard fire

The use of Cold formed steel is in demand for construction due to its varied advantages. However the knowledge of this material’s behaviours under fire is limited since it is perceived that its thinner thickness has no resistance to fire. This fire safety issue has limited the use of this material as building columns. A study was conducted to investigate the structure of cold formed steel channel column under fire condition which had testes four (4) columns. One (1) column was loaded until failure under normal condition, and three (3) columns were loaded at different degrees of utilisations under the standard ISO 834 fire condition and they were heated until failure. The rise of temperature on the column surface was monitored using thermocouple type K at three levels along the columns’ height. The analyses of the thermocouple readings were made to evaluate the mean temperature of the columns and found that the critical temperature of the cold formed steel channel columns could reach up to 600 °C for a low...

A preliminary study on the integral relationship between critical thinking and mathematical thinking among practicing civil engineers

Mathematics and engineering are inexorably and significantly linked and essentially required in analyzing and accessing thought to make good judgment when dealing in complex and varied engineering problems. A study in the current engineering education curriculum to explore how the critical thinking and mathematical thinking relates to one another, is therefore timely crucial. Unfortunately, there is not much information available explicating about the link. This paper aims to report findings of a critical review as well as to provide brief description of an on-going research aimed to investigate the dispositions of critical thinking and the relationship and integration between critical thinking and mathematical thinking during the execution of civil engineering tasks. The first part of the paper reports an in-depth review on these matters based on rather limited resources. The review showed a considerable form of congruency between these two perspectives of thinking, with some prevalent trends of engineer...