Full-scalc tests were carried out as part of an investigation into the possibility of extending a precast, two-story flat construction to three and more stories. The load-bearing walls, lightly bolted together, had no positive connection to the floor slabs, and the main object of the tests was to observe the behavior of the structure under lateral loading.
The three-story unit tested, with additional dead load to simulate a further 11/2 stories, was subjected to a horizontal uniformly distributed load, applied at the top of the third story walls. This was designed to represent a wind load of 75 mph on a five-story flat; the maximum horizontal load applied being equivalent to a 90 mph wind.
Appropriate measurements werc taken to record the lateral deflection of the building and the movement of the walls relative to the floor slabs. These measurements, together with the observed cracks, indicated a distortion of the unit, with tilting and sliding of the walls.
As a result of the information obtained from the tests, positive connection between walls and floor slabs, for multi-story construction, was recommended. The need for further research is briefly discussed.