Fact-Check: Is Bamboo Really Stronger than Steel?

By Daniel Adaji

The prevailing belief that bamboo, specifically Bambusa vulgaris, outmatches steel in strength can be found on numerous information sites, forums, and across various social media posts. For instance, the Twitter account Facts, created in March 2007, posted the statement “bamboo is stronger than steel” and has 3.4 million followers with no accounts it follows. This claim was posted on June 20, 2016, and received 158 retweets, 13 quotes, and 168 likes, along with numerous views. In addition to the Twitter post, SBC magazine online also asserted that structural bamboo surpasses steel in strength.

The SBC magazine’s post stated, “Yes, bamboo is stronger than steel in regards to tensile strength. Steel has a tensile strength of 23,000 pounds per square inch. But bamboo surpasses steel with a noticeable lead at 28,000 pounds.” Several Twitter users reacted to the post with questions regarding the authenticity of the claim.

Claim: Bamboo is stronger than steel.

Findings:

NatureFact conducted extensive online research and consulted experts in the field of construction to verify the information. An online publication engineeringdiscoveries.com published an article titled “why bamboo is stronger than steel reinforcement.” The report stated that “bamboo has quite a high tensile strength. It is comparable with steel. Apart from this, bamboo has an impermeable protective layer on the outside which protects it from rotting due to water, which is a major problem for almost all organic materials.”

The University of British Columbia UBCO found that adding 10% plastinated bamboo to a fiberglass composite increases its ability to absorb impact energy. The report explained, “With the innovation of new materials and green composites, it is easy to overlook materials like bamboo and other natural fibers,” as explained by UBCO Professor of Mechanical Engineering Dr. Abbas Milani.

These fibers are now used in many applications such as clothing, the automotive industry, packaging, and construction. Dr. Milani, Materials and Manufacturing Research Institute, noted in the report that bamboo has nearly the same strength as mild steel while exhibiting more flexibility. “With its low weight, cost, and abundant availability, bamboo is a material that has great promise but until now had one big drawback,” he said.

A careful review of the documents revealed that the authors are discussing not ‘strength’ in a general sense but rather the specific strength of the material. According to the “Methodological instructions for practical exercises and independent work for students in the field of training 08.05.01 Construction of unique buildings and structures” Moscow State University of Civil Engineering reviewed by Dr. V.G. Velichko, a Technical Service expert, “strength (MPa, N/mm2, kN/cm², kgf/cm²) – the ability of a material to resist destruction under the influence of external forces or other factors that cause internal stress in it. Strength is assessed by the tensile strength, which is conditionally equal to the stress corresponding to the load that caused the destruction of the material.”

The document also added that “to assess the strength efficiency of a material, specific strength is often used (formerly known as the coefficient of structural quality), which is determined by the ratio of strength to the relative density of the material d according to the formula Rsp = R/d.”

The table comparing the strength of the two materials is presented

Source: Moscow State University of Civil Engineering

These calculations were made by the authors of the publication, which we found on the website of the scientific publishing house Scientific&Academic Publishing. The authors compared bamboo and steel in terms of tensile strength, specifically ultimate strength (measured in MPa), density (measured in kg/m3), and specific strength.

So, in terms of strength and density, steel clearly outperforms bamboo. However, the specific gravity of bamboo (third column) is higher than that of steel (0.114 versus 0.052). Based on the findings from the research we conducted on open source materials, the claim that “bamboo is stronger than steel” is incorrect and requires clarification.

Since we are not talking about strength in general, but only about specific strength (the ratio of the ultimate strength to the density of the material), the tensile strength of steel is noticeably higher than that of the plant in question.

Verdict: Incorrect

Statements about the strength of bamboo, supposedly superior to steel, are not true and require clarification since the tensile strength of steel is noticeably higher than that of the plant in question. As for the specific strength, it is not mentioned in the statements being verified, being a very specific value used by professionals.