Fig.1 Load overlap model (isometric projection)

The following circumstances have involved the task indifficulty. The free fall of a load was hindered by a hoisting unit. Thus, itwas difficult to define the falling velocity. Moreover, damages could beexamined only from one side of the construction.
In the process of examination, the process ofconcussion of the fallen brick and the floor panel has been simulated. Thestrenght of blow has been estimated by the damages found on the accessible sideof the floor panel.
The analysis has been conducted in three phases. Thefirst phase included the computation of the SSD of the floor panel sectionunder gravity of of the supporting structures and operating covering

Fig.2. The calculated field of verticalmovements of the floor and floor panel section under gravity.

On the second phase, the the contact problem of theload fall with the initial velocity on the floor plane to the epicenter pointrevealed as a result of a customer's examination has been solved. In theabsence of the initial load velocity information, the missing information wasrevealed by a cut-and-try numerical experiment and by using the knowndimensions and the shape of damage areas of floor plates, road slabs andnon-load partition walls etc.
On the third phase, the floor plane section with thecenter in the epicenter poing of the load fall was loaded quasistatically andregularly with the pressure allocated throughout the whole space.

Fig.3. The calculated field of maximal tensionstresses on the floor plane under gravity

Fig.4. The calculated concrete damage area(dynamic projection). Top and bottom view

It has been revealed that the axial tensions in thetop effective reinforcement amounted to 200MPa and 100MPa correspondingly(Fig.5), which doesn't go beyond the limit of reinforcement steel yield.
Figures 5 and 6 show that tensions in the top concretezone have locally exceeded the breaking pulling stress, which evidences thatthere are flaws in the zone that is normally in a state of compression.

Fig.5. The calculated axial tensions in theeffective reinforcement before and after the loss of load-carrying capacity.

The stress-strain analysis in the reinforced concretehas shown that reinforcement wires are elastic, and the through-plane-crackwidth lies in the permissible range.
This let us claim that the remnant load-carryingcapacity of the floor plane is sufficient for a further exploitation of theconstruction.
This expertise enabled the customer to take a decisionon further actions concerning this building as a main business assets resource.

Fig.6 The calculated field of verticalmovements of the floor panel section under gravity and load fall.

Moscow 2009