Test performed at Structural Engineering laboratory at Reykjavik University (www.ru.is/sel).
The shear force displayed is the point load (the force from the jack divided by two).
Abstract of the thesis
Shear failures in concrete structures are very hazardous. These failures can rarely be predicted and often happen explosively. For decades, tests have been done to study this phenomenon, in order to try to solve the riddle that shear is. Researchers have become more knowledgeable about shear and what the most important influences are. However, Eurocode’s shear equation formula (without shear reinforcement) is based on semi-empirical procedures.
My experiment involved testing concrete beams of variable height and consequently variable a/d ratio and comparing the test results to three building codes; ACI 318-08, ENV 1992-1-1:1991 and EC-2:2004.
I was also interested in studying shear and its most important influences.
Six series of beams were cast, three of each series, a total of eighteen beams. They were reinforced in the tensile area but not for shear. The variables were two; beams of different height (105mm – 335mm) and reinforcing steel percentage (1.31% – 1.55%).
My findings were that the ACI 318-08 code gives a very conservative conclusion. The Eurocode valid today (EC-2:2004) gives a safe estimation when compared to failure of the beam. The code also predicts the first shear crack for the beams except the deepest ones. When the formula is applied with the partial safety factor (γc) it becomes very safe. The ENV 1992-1-1:1991 code which is the predecessor to today’s code does not give good enough results and over estimates the shear resistance in some instances, if not calculated with the partial safety factor.
The thesis and more detailed information about the test can be found at www.ru.is/sel