Senior Technical Officer and Research Support staff
Jan.2010 – Present
University of Technology Sydney, Sydney, NSW
Faculty of engineering & information technology FEIT
Materials Testing Laboratory
Structural design engineer
Jan.2007 – Aug. 2009
B. Khadim and Associates Architects, Engineers, Dubai, UAE
Structural design engineer
Jan 2004– Dec 2006
IDRIS SOUDDO Architects, Engineers and Planners plc, Asmara, Eritrea
Society of Engineers-UAE
Association of Eritrean Engineers and Architects
Long-term behavior of timber-concrete composite beams and timber only floor modules
Hailu, M, Shrestha, R & Crews, K 2013, 'Long-Term Deflection of Timber-Concrete Composite Beams in Cyclic Humidity Conditions in Bending', Composite Construction in Steel and Concrete VII - Proceedings of the 2013 International Conference on Composite Construction in Steel and Concrete, International Conference On Composite Construction In Steel And Concrete, ASCE, North Queensland, Australia, pp. 146-157.View/Download from: Publisher's site
© ASCE. A laboratory investigation to determine the long-term behaviour of timber-concrete composite (TCC) beams was started from August 2010 at the University of Technology, Sydney. The test was conducted on four six-meter-span TCC beams; this paper reports the results to-date for only two beams. The materials used are laminated veneer lumber (LVL) for the joists and 32 MPa concrete for the flanges. From the start of the test (August 2010), the specimens have been under sustained loads of (1.7kPa) whilst the environmental conditions have been cyclically alternated between normal and very humid conditions (typical cycle duration is six to eight weeks) and the temperature remains quasi constant (22 °C). During the test, the mid-span deflection, moisture content of the timber beams and relative humidity of the air are continuously monitored. The investigation is still continuing and this paper reports the results of the experimental investigation for the last two and half years.
Hailu, M, Shrestha, R & Crews, KI 2014, 'Timber composite floor beams under 2 years lon-term load', Proceedings of the 23rd Australasian Conference on the Mechanics of Structures and Materials (ACMSM23), Australasian Conference on the Mechanics of Structures and Materials, Southern Cross University, Byron Bay, Australia, pp. 607-612.
The long-term behaviour of composite beams is characterised by the response of its component parts (flanges and webs) to load, moisture content, temperature and relative humidity of the environment. This paper reports the results of a two years long-term test on two 6 m span composite floor beams made of laminated veneer lumber (LVL) under service load performed in an indoor, semi-controlled, and unheated environment. The environmental conditions were characterized by artificially induced cyclic air humidity with quasi-constant temperature. These conditions can be characterized as reasonably severe and presumably close to service class 3 according to Eurocode 5. During the test, the mid-span deflection, moisture content and air humidity were monitored. The paper recommends a creep factor for design of timber composite beams in severe environmental conditions.
Hailu, M 2013, 'Long-term behaviour of Timber-Concrete Composite Beams in Cyclic Humidity Conditions', Composite Construction VII, Composite Construction VII, Composite construction VII, Palm Cove Sea, Queensland,Australia, pp. 1-13.
Session 6C- Composite Beams 3
Hailu, M, Gerber, C, Shrestha, R & Crews, KI 2012, 'Residual strength of timber-concrete composite beams after long-term test', From materials to structures: Advancement through innovation, Australasian Conference on the Mechanics of Structures and Materials, CRC press/Balkema, Sydney, Australia, pp. 73-78.View/Download from: Publisher's site
This paper presents a comprehensive serviceability investigation that commenced at the University of Technology, Sydney, in August 2010. The tests have been conducted on two 5.8 m span timber concrete composite beams (referred to as TCC beams here onwards) with two different connector types: Type 17 screws and four notches with coach screws. The materials used are laminated veneer lumber (LVL) for the beams and 32-MPa concrete for the flanges. Three serviceability tests were conducted on the beams, two short-term (quasi-static loading) and one longterm (sustained loading) tests. The short-term tests were completed before the start and after the end of the long-term test. Both short-term tests aim to identify the initial and residual stiffness respectively. The ultimate strength of the specimens was also investigated in the course of the last test. During the long-term test (duration of approximately 500 days), the specimens were under a sustained load (1.7 kPa) whilst the environmental conditions were cyclically alternated between normal and very humid conditions â a typical cycle duration was six to eight weeks. The temperature remained quasi constant (22â¦C). The mid-span deflection, LVL-beam EMC and relative humidity of the air were continuously monitored during the test. This test aim to quantify the creep effect of the TCC beams. The paper starts with a brief literature review, continues with a presentation of the laboratory investigations and then presents a thorough discussion and analysis of the long-term and short-term investigations.
Hailu, M, Crews, KI, Gerber, C & S, R 2012, 'LONG âTERM EXPERIMENTAL TEST ON TIMBERCONCRETE COMPOSITE BEAMS', World Conference on Timber Engineering (WCTE 2012), Curran association, Auckland, New Zealand, pp. 249-250.
The paper presents the results and observations of the long-term test to date. It will discuss numerical models found in the literature and examine their fitness to predict the long-term behavioural responses of the specimens. Recommendations for the long-term design of TCC solutions are also presented.