Date of Award
Santa Clara : Santa Clara University, 2018.
Cob is a sustainable building material used in residential applications as a replacement for typical one-story timber or concrete structures. Cob heavily lacks the testing and modern research required for permissible construction under current residential building codes. Further tests involving earthquake and lateral loading are required to implement cob into the California Residential Building Code. In this report, four cob walls, each with different reinforcement mechanisms, were tested to observe their failure modes and find the maximum deflection and load of each wall. Through this testing, it was determined that steel reinforcement within cob walls can provide more ductile behavior and increase both maximum loads and displacement of the material. Analysis showed the ideal reinforced cob wall had an estimated Response Modification Factor of 2.5 which reduces design loads significantly when considering lateral seismic loading. The combination of vertical steel and lateral wire mesh reinforcement throughout a cob wall proved to be the most efficient way to reinforce the structure. The key to properly reinforce cob involves using materials that are large enough to transfer load but small enough to not create large voids within the cob matrix. There is potential for the material to be used in permitted buildings, yet much more full scale research must be done to solidify its capabilities.
Eberhard, Daniel; Novara, Joseph; and Popovec, Brandon, "Cob: A Sustainable Building Material" (2018). Civil Engineering Senior Theses. 66.