User:BarisBaran97/sandbox

Abstract
In search of more sustainable ways, the construction industry has put its attention at Bamboo. Current research towards Bamboo as a structural material is showing promising results.

Various papers were reviewed in order to get a better understanding of the current state of the art of bamboo. These papers ranged from general applications for bamboo as a structural element, to detailed experiments where multiple bamboo columns were tested in axial compression and its results were compared with theoretical results. In addition, the environmental impacts of Laminated Bamboo Lumber (LBL) were also researched. It was found that bamboo has mechanical and thermal properties similar to those found in mass timber which gives hopes towards future applications as a structural material. However, not enough testing has been done in order to fully support these claims. Regarding its sustainability aspect, it has been shown that bamboo is more sustainable than traditional construction materials, including wood. This was shown to be the case in China, perhaps the country more advanced in bamboo applications. In the future, it must be proved that bamboo can also be a sustainable alternative for other countries.

Manufacturing
The origins of engineered bamboo are still a mystery. However, it is clear that it has a huge potential in construction and there is a need for standardization in manufacturing. The most common types of bamboo that are currently in use are Laminated Bamboo Lumber (LBL) and Bamboo Scrimber (densified bamboo). The production of engineered bamboo starts from the bamboo culms. First, they are cut from the plantation and transported to a front end factory. This factory is in charge of cutting, splitting and drying the bamboo strips. This way, waxy exterior and interior materials are removed. Then, the material is transported to another factory where the bamboo sections are assembled and pressed with adhesives. After this, the material is its final form), and it's treated with heat and/or chemicals to dry off and prevent mold, as well as weatherproofing it. To obtain the color, either strips can be boiled in a hydrogen peroxide or caramelization can be applied.

Environmental Impact
Laminated Bamboo Lumber (LBL) is picking up in popularity due to its low carbon emissions, ease of production and good mechanical properties. LBL is classified as a carbon sink, meaning that during their lifecycle they absorb more carbon than they emit. According to King et al, the annual output of bamboo can reach 78.3 tons, 4.47 times that of wood and its sustainability is 20 times that of wood. In addition, while traditional timber takes decades from planting and harvesting, bamboo can be harvested in as short as 3 years.

A Life Cycle Analysis (LCA) was done by Xu et al (2022), and the results are promising. This study considered 4 phases, planting, production, transportation and operation and maintenance. This study showed that bamboo is more sustainable than traditional construction materials. However, there are challenges for bamboo to overcome before it becomes mainstream. First, most of the bamboo production takes place in China. Although this may be a sustainable option for China, transport of goods around the world will reduce the sustainability of bamboo. Secondly, adhesives play an important role in production but the commonly used adhesives are not bio-based and may be toxic to humans. Finally, water consumption during the planting phase is very high which may put additional strains on water scarce communities. Even with these challenges, bamboo is still one of the most sustainable options known to date for typical construction material. Given that the design process leads to 80% of the environmental impact of a product (EC, 2012), it is crucial to provide engineer and architects with more options to select from.

Material Properties and Structural Applicability
Both laminated and densified bamboo have very similar mechanical properties. They show linear behavior in tension and shear and tri-linear behavior in compression and bending.

Tension
Parallel to fibers tensile strength is higher than perpendicular to fibers tensile strength. Its failure mechanism is characterized by being a brittle failure. Angle of loading is critical. Therefore, one should be careful about this material, especially if it is in an earthquake zone because then many components of the structure might experience loading from very different angles.

Compression
Similarly to tension, longitudinal compressive strength is higher than transverse compressive strength. Generally, the same testing methods with wood are used to test engineered bamboo. However, the aspect ratio for wood specimens is not appropriate for this material since it results in buckling failure. Better testing methods for compression should be explored and standardized to get more accurate results.

Shear
Shear dominates the mode of failure in engineered bamboo. Thus, it is critical to have a standardized testing method. However, similar to compression, there is an ongoing argument about testing methods for shear strength. Two common approaches are shear-block approach and composite shear testing approach.

Bending
Bamboo is a really flexible material and can deflect a lot without failing. This may be critical for serviceability purposes and deflection limits in design codes must be checked thoroughly.

Thermal Properties
There is a handful of research going on about thermal properties of engineered bamboo. However, the latest research agrees that the thermal conductivity of engineered bamboo is similar to engineered wood products. Moreover, laminated bamboo has a higher thermal conductivity than bamboo scrimber.

When it comes to fire resistance, although flammability of engineered bamboo is similar to normal wood products, the behavior of the material in high temperatures differs a lot. Further research is needed in this area.

Current Practice and Future Use
Even though some countries like Colombia took the initiative and built pedestrian bridges by reinforcing the engineered bamboo with steel reinforcement, current practice of engineered bamboo is mostly aesthetic. However, it is commonly used for non-structural floorings. For future use, a possible alternative might be in building facades since its thermal properties show great potential and it looks aesthetically pleasing.