PART 1: COLUMN MEMBER COMPRESSION CHECKS

Q2. In assignment 3 we checked the section strength of the SG8 timber studs in the wall along gridline A, with nominal section size 100mm x 50mm (these are rough sawn dimensions and once dried, assume section size is 90mm x 45mm) for a ULS compression load due to 1.2G+1.5Q of N*= 21kN. Now member buckling needs to be checked (i.e. do the checks as per Chapter 3 of reader) noting that the stud height is 3m and blocking is provided at 1m centers, as shown in Figure 8. Report the critical (maximum) ratio of axial force demand to capacity. For the buckling in the out-of-plane wall direction, treat as “studs in light framing” (refer Table 3.1 of reader) whereas for other direction, assume that buckling is not a problem as the wall lining would laterally restrain the post buckling in the line of the wall.

Report the ratio of the axial force demand to capacity (as a %).

PART 1: COLUMN MEMBER COMPRESSION CHECKS

Q1)b. What is the axial force demand to capacity ratio (as a %) for the minor-axis direction. [%]

PART 1: COLUMN MEMBER COMPRESSION CHECKS

 Q1. Do calculations to check whether the 6.5m long columns on grid B5 (shown as a post in Figure 7), with nominal section size 250 x 50mm (these are rough sawn dimensions and once dried, assume section size is 240mm x 45mm) are able to sustain a ULS compression load due to 1.2G+1.5Q of N*= 30kN. Assume that the timber is SG8 and note that both the section strength and member buckling needs to be checked (i.e. do the checks as per Chapter 3 of reader). Report the ratio of demand to capacity. For the column end restraint conditions, assume that for buckling in the major axis direction (i.e. that involves major-axis bending), the foundation provides restraint in position only and the roof level restrains the top of the column in position only too. For buckling in the minor-axis direction (i.e. that involves minor-axis bending), note that the wall girts shown in Figure 7 act as positional restraints. Report the axial force demand to capacity ratio (as a %) for both the major- and minor-axis directions.

Q1a. What is the axial force demands to capacity ratio (as a %) for the major-axis direction. [%]

Q7. Do calculations to check whether the floor joists with 300mm x 50mm (280 x 45mm) sections are able to resist a shear force demand, due to 1.2G+1.5Q, of V*= 5kN. Report the ratio of demand to capacity; V*/ϕV_n. [%]

Q5. Do calculations to check whether SG8 main beams (pairs of 300mm x 75mm (i.e. 280 x 70mm)) sections can resist a maximum moment demand, due to 1.2G+1.5Q, of M*= 56kNm (associated with the case where the mid-span column is present). Assume that the pairs of beams are connected with blocking so that they act as a combined parallel system to resist the applied loads (i.e. consider k₉ factor when computing the strength of the two members resisting load in parallel – refer Eqn 2.4.5.3 and Figure 2.3 of AS/NZS1720.1:2022). Report the ratio of demand to capacity; M*/ϕM_n. [%]

Q6. The previous calculations indicate that the proposed main beam section is unable to resist the design moment. To address this, you decide to fill in the 140mm gap between the two beams with an additional two 300mm x 75mm (i.e. 280 x 70mm) sections. You also decide to specify a higher timber grade for the beams, corresponding to SG12. Do calculations to check whether SG12 main beams, realized with four 300mm x 75mm (i.e. 280 x 70mm) sections, would be able to resist a design moment of M*= 57kNm (M* is slightly higher due to increased self-weight). Report the ratio of demand to capacity; M*/ϕM_n. [%]

Q4. Do calculations to check whether SG8 floor joists with 300mm x 50mm (280 x 45mm) sections are able to resist a maximum moment demand, due to 1.2G+1.5Q, of M*= 3.9kNm. Note that because the floor joists are connected via plywood sheets (assume the sheets are 1200mm wide), a strength-sharing factor, k₉, has been evaluated for you as k₉ = 1.19. Report the ratio of M*/ϕM_n. [%]

Q3. Now consider the studs within the walls that support the mezzanine floor. To do this, undertake calculations to check whether 100mm x 50mm rectangular section (90mm x 45mm dried size) timber sections would be able to sustain a ULS compression load due to 1.2G+1.5Q of N*= 21kN. Assume that the timber is SG8 and that member buckling is not an issue (i.e. just do the section checks as per Chapter 2 of reader). Report the ratio of demand to capacity; N*/ϕN_nc,timber. [%]

Q2. Do calculations to check whether the columns supporting the mezzanine floor, with nominal section size 150mm square (these are rough sawn dimensions and once dried, assume section size is 140mm square) are able to sustain a ULS compression load due to 1.2G + 1.5Q of N* = 150kN. Assume that the timber is SG8 and that member buckling is not an issue (i.e. just do the section checks as per Chapter 2 of reader). Report the ratio of demand to capacity; N*/ϕN_nc,timber. [%]

Q1. Do calculations to check whether the steel X bracing in the walls, realised with 20mm diameter grade 300 rods (f_y = 300MPa), is able to resist the wind load in the East-West direction that generates a design tension load of N* = 70kN for the ULS factored load combination (1.2G+1.2Wu+1.5Q). Assume a form factor of k_f =1.0 and report the ratio of demand to capacity; N*/ϕN_s,steel. [%]