Lateral stiffening systems for tall timber buildings – tube-in-tube systems

Figures & data

Figure 1. Schematic representation of the investigated structure typologies, based on Fazlur Kahn (Ali and Moon 2007) (left) and schematic representation of the tube-in-tube system with its structural behaviour (right).

Figure 2. Tube-in-tube system.

Figure 3. Structural system (left) and the statically equivalent model for determining the rotational stiffness of the beam-column joint (right).

Figure 4. Statically equivalent member dimensions representing the approach of the joint stiffness K_rot in comparison to the member dimensions.

Table 1. Overview of the simulation-parameters for the different systems.

Parameter	Description		Tube-in-tube
Structure			Min	Max	Step	Unit	Dim.
Building	Bay length	lb	2.40	4.00	0.4	[m]	5
	Bay number	nb	6.00	14.00	2.0	[-]	5
	Floor height	lc	3.50	3.50	–	[m]	1
	Floor number	nc	15.00	42.00	3.0	[-]	10
Components	Column width	bc	0.36	0.36	–	[m]	1
	Column height	hc	0.40	0.80	0.08	[m]	6
	Beam width	bb	0.36	0.36	–	[m]	1
	Beam height	hb	0.40	0.80	0.08	[m]	6
	Bracing width	bbr	0.36	0.36	–	[m]	1
	Bracing height	hbr	0.40	0.80	0.08	[m]	6
				(*) changing simultaineously
Material	All members		GL28h	GL48h	GL75	[–]	3
Joints	Rotational stiffness ratio	α	0.10	1.0	0.15	[–]	7
Vertical load	Surface load/floor	pfloor	5.00	10.00	2.50	[kN/m^2]	3
Number of simulations						567’000

Figure 5. Illustration of the parameters.

Figure 6. Comparison of the peak accelerations and the natural frequency f_n (left) for the analysed tube-in-tube systems (right).

Figure 7. A single-degree-of-freedom system (a) is used to represent the building stiffness in the first mode. The equivalent spring-mass system (b) is denoted by the stiffness K (c).

Figure 8. Comparison of parameters with constant reference values. The reference values are: n_c = 33, v_b,0 =  25.0 m/s, p_floor = 7.5 kN/m2, δ_s = 0.05.

Figure 9. Natural frequencies for different building heights and widths.

Figure 10. Peak accelerations for different building heights and widths.

Ali, M. M. and Moon, K. S. (2007) Structural developments in tall buildings: current trends and future prospects. Architectural Science Review, 50(3), 205–223.

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