Feasibility Study of Mass-Timber Cores for the UBC Tall Wood Building
Abstract
:1. Introduction
2. UBC Tall Wood Building
2.1. Background
2.2. Building Regulation
2.3. Structural System
2.4. Connection Design
2.5. Objectives
3. Numerical Investigation
3.1. Design Options
3.2. Material Parameters
3.3. Design Requirements
3.4. Numerical Model
3.5. Analysis
4. Results and Discussion
4.1. Dynamic Elastic Behavior
4.2. Lateral Response
4.3. Discussion
5. Life Cycle Analyses
5.1. Methods
5.2. Results and Discussion
6. Conclusions
- The side position of the cores induced a notable torsional component on the lateral response of the building, particularly evident in the case of mass-timber cores. The findings suggest the inclusion of additional shear walls to help reduce plan torsional sensitivity;
- Only design options D-4 and D-7 with LVL walls met all NBCC lateral design requirements; however, only the solution with additional ‘C-shaped’ walls appears feasible since it is unrealistic for timber panels to use completely rigid joints to build monolithic cores as assumed for D-4;
- The LVL design D-5, which had the stiffness of cores reduced by 50% to account for the joints between panels as per the authors simplified preliminary design assumption, exhibited seismic and wind performance close to code limits of 2.5% and 0.2%, respectively;
- Even for a model assuming monolithic cores, it seems unreasonable to pursue the solution with CLT for the TWB with the original layout. This recommendation is also conditioned by the commercially available CLT panel thickness, currently limited to 315 mm in Canada;
- The LCA demonstrated that the use of a mass-timber LLRS for the UBC TWB would have significant environmental benefits in regard to the impact categories recognized by LEED v4;
- Future research should investigate (i) the stiffness and capacity of horizontal and vertical connections for CLT and LVL cores; (ii) the impact of adding un-bonded post-tensioned cables; and (iii) the behavior of balloon-framed CLT/LVL systems to provide Ro and Rd factors;
- With such further research, code provisions and design rules could be developed to increase the use of mass-timber as lateral load-resisting systems.
Author Contributions
Funding
Conflicts of Interest
References
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Property | Concrete | CLT | LVL |
---|---|---|---|
E1 | 26,540 | 12,400 (0°-layers) 9500 (90°-layers) | 13,800 |
G23 | 11,058 | 78 (0°-layers); 59 (90°-layers) | 55 |
G12, G13 | 775 (0°-layers); 594 (90°-layers) | 550 |
Design | T1 (s) | T2 (s) | T3 (s) | ∑mx (%) | ∑my (%) |
---|---|---|---|---|---|
D-1* | 2.0 | 1.7 | 1.4 | n/a | n/a |
D-1 | 2.0 | 1.5 | 1.3 | 77 | 61 |
D-2 | 4.3 | 3.0 | 2.8 | 87 | 84 |
D-3 | 6.1 | 4.3 | 4.3 | 89 | 89 |
D-4 | 3.0 | 2.1 | 2.0 | 87 | 86 |
D-5 | 4.3 | 3.1 | 3.0 | 89 | 90 |
D-6 | 3.9 | 3.5 | 3.1 | 83 | 83 |
D-7 | 2.8 | 2.6 | 2.3 | 84 | 84 |
Design | Vb,X (kN) | Vb,Y (kN) | θmax,X (%) | θmax,Y (%) |
---|---|---|---|---|
D-1 | 34,285 (6122) | 36,847 (7184) | 1.1 | 1.3 |
D-2 | 20,882 (19,322) | 30,209 (23,238) | 1.9 | 2.7 |
D-3 | 22,662 (19,322) | 25,118 (19,322) | 3.5 | 3.3 |
D-4 | 28,617 (22,013) | 34,624 (26,634) | 1.5 | 1.8 |
D-5 | 21,405 (19,931) | 30,870 (23,746) | 1.8 | 2.6 |
D-6 | 25,056 (19,743) | 27,752 (21,348) | 1.6 | 3.0 |
D-7 | 30,682 (23,602) | 33,829 (26,022) | 1.3 | 2.5 |
Design | Vb,X (kN) | Vb,Y (kN) | θmax,X (%) | θmax,Y (%) |
---|---|---|---|---|
D-1 | 615 | 2319 | 0.02 | 0.04 |
D-2 | 804 | 2856 | 0.13 | 0.23 |
D-3 | 925 | 3286 | 0.27 | 0.52 |
D-4 | 699 | 2538 | 0.06 | 0.09 |
D-5 | 808 | 2867 | 0.12 | 0.22 |
D-6 | 747 | 2633 | 0.07 | 0.32 |
D-7 | 668 | 2412 | 0.04 | 0.14 |
Design | Cores | Caps + Stairs | ||
---|---|---|---|---|
Material | Volume (m3) | Material | Volume (m3) | |
D-1 | Concrete | 1314 | Concrete | 147 |
D-2 | CLT | 928 | CLT | 116 |
D-4 | LVL | 1311 | CLT | 116 |
D-6 | CLT | 1583 | CLT | 116 |
D-7 | LVL | 2236 | CLT | 116 |
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Connolly, T.; Loss, C.; Iqbal, A.; Tannert, T. Feasibility Study of Mass-Timber Cores for the UBC Tall Wood Building. Buildings 2018, 8, 98. https://doi.org/10.3390/buildings8080098
Connolly T, Loss C, Iqbal A, Tannert T. Feasibility Study of Mass-Timber Cores for the UBC Tall Wood Building. Buildings. 2018; 8(8):98. https://doi.org/10.3390/buildings8080098
Chicago/Turabian StyleConnolly, Thomas, Cristiano Loss, Asif Iqbal, and Thomas Tannert. 2018. "Feasibility Study of Mass-Timber Cores for the UBC Tall Wood Building" Buildings 8, no. 8: 98. https://doi.org/10.3390/buildings8080098