This report addresses serviceability issues of tall wood buildings focusing on their vibration and sound insulation performance. The sound insulation and vibration performance may not affect the building’s safety, but affects the occupants’ comfort and the proper operation of the buildings and the function of sensitive equipment...
Advanced sustainable lateral load resisting systems that combine ductile and recyclable materials offer a viable solution to resist seismic load effects in environmentally responsible ways. This paper presents the seismic response of a post-tensioned timber-steel hybrid braced frame. This hybrid system combines glulam frame with steel braces to improve lateral stiffness while providing self-centreing capability under seismic loads. The proposed system is first presented. A detailed numerical model of the proposed system is then developed with emphasis on the connections and inelastic response of bracing members. Various types of braced frames including diagonal, cross and chevron configurations are numerically examined to assess the viability of the proposed concept and to confirm the efficiency of the system. A summary of initial findings is presented to demonstrate usefulness of the hybrid system. The results demonstrate that the proposed system increases overall lateral stiffness and ductility while still being able to achieve self-centring. Some additional information on connection details are provided for implementation in practical structures. The braced-frame solution is expected to widen options for lateral load resisting systems for mid-to-high-rise buildings.
Related sections in the International Building Code (IBC) were reviewed regarding use of wood components in non-combustible buildings, and light-frame wood buildings or heavy timber buildings greater than 4-storeys in height.
The highlights of this review are:
a) Fire-retardant-treated (FRT) wood can be used in partitions when the required fire-resistance rating is not more than 2 hours. This includes all types and occupancy groups of Types I and II construction;
b) FRT wood can be used in non-bearing exterior walls in Type I, II, III and IV construction;
c) Wood components can be used in interior walls for Type III and IV construction;
d) Wood components can be used in both interior and exterior walls for Type V construction.
When a sprinkler system is installed according to NFPA 13 , it is possible to build a light-frame wood building or heavy timber building over 4-storeys according to the following provisions:
a) Type IIIA 6-storey light-frame wood buildings using FRT wood for exterior walls for Occupancy group B (Business), H-4, and 5-storey light-frame wood buildings for Occupancy group F-2, H-3, I-1(Institutional), R (Residential), S-2;
b) Type IIIB 5-storey light-frame wood buildings using FRT wood for exterior walls for Occupancy group R;
c) Type IV (HT) 6-storeys timber buildings for Occupancy group B, F-2, H-4 and S-2;
d) Type IV (HT) 5-storeys timber buildings for Occupancy group F-1, H-3, I-1, R, S-1 and U.
This project evaluates the National Building Codes of Canada (NBCC) clauses relevant to fire performance and performance requirements of non-load-bearing wood-frame in-fill walls in concrete/steel hybrid buildings. Related clauses in NBCC are reviewed regarding the use of wood components and non-load bearing wall systems in non-combustible buildings. The highlights of this review are:
§ An exterior non-loadbearing wall assembly with combustible components is allowed in non-combustible construction if:
a) Building height is not more than 3 storeys or has a sprinkler system throughout ;
b) The interior surfaces of the wall assembly are protected by a thermal barrier ; and
c) The wall assembly satisfied the testing criteria for CAN/ULC S134 ;
§ Combustible interior wall finishes, other than foamed plastics, are allowed in non-combustible construction if the thickness is not greater than 25 mm and their flame spread rating (FSR) is not more than 150 ;
§ Combustible insulation, other than foamed plastics, is allowed in non-combustible construction if the flame-spread rating not more than 25 ;
§ Combustible insulation with a FSR not less than 25 and not more than 500 is allowed in exterior and interior walls of non-combustible construction if the building is non-sprinklered and not more than 18 m or sprinklered and protected by a thermal barrier ;
§ There are no obstacles for using wood-frame in-fill wall systems for interior partition walls in hybrid buildings:
a) For non-sprinklered buildings not greater than 3 storeys or a floor area not greater than 600 m2 ;
b) For sprinklered buildings.
§ Non-combustible construction allows combustible elements in partition walls in the following instances:
a) Solid lumber partitions located in a fire compartment area are permitted in a non-sprinklered floor area not greater than 600 m2 with restrictions ;
b) Solid lumber partitions not less than 38 mm thick and partitions that contain wood framing are permitted with restrictions.
§ Combustible cladding can be used under the following circumstances:
a) When a wall assembly with exposing building face is between 10 to 25% tested by CAN/ULC-S134 and complies with Article 220.127.116.11 ;
b) When a wall assembly with exposing building face is between 25 to 50%, is sprinklered throughout, installed on a gypsum board sheathing, and has a FSR not more than 25 (with restrictions) ;
c) When a wall assembly with exposing building face is between 50 to 100%, cladding can be combustible for group A, B, C, D, E, F.
§ When a building is required to be of non-combustible construction, combustible elements are limited to the requirements in Subsection 3.1.5 on non-combustible construction ;
§ When comparing the NBCC with the International Building Code (IBC), the IBC is more in favour of using FRT wood frame in-fill walls with one more storey.