Questions

• Why is the force in the lower tie constant along its entire length?

• Is the tie necessary if the supports prevent horizontal movement? Why?

• Which load configuration activates a "fan" response mode?

• Which load configuration activates an "arch" response mode?

• Identify in both cases where the bi-axial compression zones are located.

• Does the reinforcement that is not in the lower tie play an important role in the response of the first sample?

• Can a hole be made in the middle of the first sample just above the tie? And in the vicinity of its support zone?

• In the case of the suspended load, if we consider that the stirrups have no bond but are properly anchored at the top by an anchoring plate, does the response of the second element change? What is the most likely behaviour?

• In the case of the suspended load, suppose the stirrups are stopped halfway up the beam. What influence will this have on the stresses in the concrete and on the force in the lower tie?

• In the case of the suspended load, suppose now that the reinforcement is placed along the diagonal directions of the sample. What influence will this have on the behaviour of the concrete? Should reinforcement be placed in the lower tie in this case?

• Can cracking in the case of the suspended load influence the ultimate load of the element? Why?

• Study the possible stress fields for each case using the results from the applet.

Tests on walls taken from F. Leonhardt et R. Walther, 'Wandartige Träger', DAFS, 1966