Cross-laminated timber (CLT) or XLAM is a large-scale, prefabricated, solid engineered timber panel. A CLT panel consists of several layers of kiln-dried lumber boards stacked in alternating directions, bonded with structural adhesives, and pressed to form a solid, straight, rectangular panel. It is consisting of an odd number of layers (usually, three to seven) and may be sanded or pre-finished before shipping.
While at the mill, CLT panels are cut to size, including door and window openings, with state-of-the art CNC (Computer Numerical Controlled) routers, capable of making complex cuts with high precision. Finished CLT panels are exceptionally stiff, strong, and stable, handling load transfer on all sides.
Lightweight yet very strong, with superior acoustic, fire, seismic, and thermal performance, CLT is also fast and easy to install, generating almost no waste on site.
CLT offers design flexibility and low environmental impacts. For these reasons, cross-laminated timber is proving to be a highly advantageous alternative to conventional materials like concrete, masonry, or steel, especially for multi-story building construction.
The structural project development design analysis on safety and durability is done according to Brazil codes and Eurocodes.
BRAZIL CODES – Brazilian Standards (ABNT):
• NBR 7190:2022 - Timber Structure Design
• NBR 6120:1980 - Loads for calculation of building structures - Procedure
• NBR 6123:1988 - Wind Forces on Buildings - Procedure
• NBR 8681:2004 - Actions and safety in structures - Procedure
• NBR 16.143:2013 - Timber Preservation, Use category system
• NBR 16.936:2023 - Buildings in light timber frame
EUROCODES:
• EN 1990 - Eurocode 0: Basis of structural design
• EN 1993-1-1 - Eurocode 3: Design of steel structures - Part 1-1: General rules and rules for buildings
• EN 1993-1-5 - Eurocode 3: Design of steel structures - Part 1-5: Plated structural elements
• EN 1993-1-8 - Eurocode 3: Design of steel structures - Part 1-8: Design of joints
• EN 1995-1-1 - Eurocode 5: Design of timber structures - Part 1-1: General - Common rules and rules for buildings
• EN 1995-1-2 - Eurocode 5: Design of timber structures - Part 1-2: General - Structural fire design
• EN 1998-1-1 - Eurocode 8: Design of structures for earthquake resistance - Part 1-1: General rules, seismic actions, and rules for buildings
• EN 338 - Structural timber - Strength classes
When timber is exposed to heat, it goes through a thermal breakdown process and a layer of char forms on its surface. Wood has around a 10–12% moisture content and when it ignites, the moisture evaporates, and the charring process begins. This charred layer acts as a natural insulator which protects the inner core.
The surviving structure in the uncharred inner core remains relativelyunaffected, maintaining its structural strength and stability. Typically, a wood structure can remain stable for up to two hours when exposed to a fully developed fire.
“Contrary to popular belief, wood is a natural fire-resistant element that can remain highlystable in an event of fire by creating aprotective charred layer.”
Cost on the foundation of the building
Even as a rigid MASS Timber structure, Structural Timber is lighter than the conventional steel & concrete system. Therefore, the loads reactions to the foundation is less and the Structural Timber system requires smaller sections of the foundation compared to the conventional system.
Accuracy of the pre-fabricated Structural Timber elements
Structural Timber elements are pre-fabricated in accordance with the design of the project including the precise CNC cutting and profiling at the factory. The elements will be delivered to site as “cut-to-size” pieces and ready for immediate assembly. This procedure helps avoid any additional work at site which prevents human error and unnecessary waste of materials.
Easy and clean construction method with project timeline accuracy
The Structural Timber system installation requirement is limited to pre-assembly, lifting and fixation works. The construction method requires minimum equipment such as crane, man lift and mobile scaffolding on site. Therefore, it does notrequire huge manpower / laborers on site, it reduces the site traffic / congestion and most importantly, it delivers the project accurately as planned.