PART 2: BEAM MEMBER BENDING STRENGTH CHECK

Q4) Now, for the portal frame, you wish to investigate whether a timber glulam portal frame could be used instead of the steel system shown in the sketches. The beam should be able to resist the bending moment demands shown in Figure 6 due to the load case of 1.4G. As such, do calculations to find the glulam portal section depth required to ensure the beam has sufficient flexural strength (be sure to check the member strength considering the possibility of flexural-torsional buckling). Assume that the glulam section will be 120mm wide, will use GL12 timber, and that you will need to specify the required section depth of the glulam considering 45mm laminations (see Figure 9). Glulam material properties from AS NZS1720.1 are provided. Size the beam section for the maximum bending moment acting at the mid-span of the beam, shown in Figure 6, of M* = 120kNm (and assume this value accounts for the self-weight of the beam). Report the bending moment demand to capacity ratio (as a %).

Q4)a What is the slenderness coefficient, S1?