The purpose of this Bachelor’s thesis was to study the effect of the length of the gap in the steel truss on the resistances of the gapped K-joint. The thesis was commissioned by Häme University of Applied Sciences Sheet Metal Centre which wanted to research the most likely failing mechanisms of the joint. The main goal was to find the common factor between small gaps and weak loading resistances.

Another aim was also to check how close to the true loading resistance the Eurocode standard of steel design was. Utilizing The Yield Line Theory in design calculations in the yield of the chord face was also studied.

The knowledge obtained during studies of structural engineering about structural mechanics and statics and design of the steel structures were applied extensively in the thesis. Only few published sources were utilized as not much research about the subject exists. The design of joints and practical experiences were discussed with experts in the field. The author’s own experience in the construction field was used in fabricating the support frame and the prototype.

According to the tests conducted in the thesis the Eurocode design codex of the gapped K-joint can be concluded to be faulty. Design resistances of the calculations were much higher than the real resistances that were measured in the tests because the calculation doesn’t quite fit into the subject. Based on the results obtained in the thesis further studies on the subject are recommended. Comparable results are needed to verify the conclusions drawn from the test results.