When Did THIS Happen?
We are often asked to determine the age or the history of various structural damages. For example, we may be asked if we can determine the age or history of cracking in a wall, driveway, floor, etc.?
The age and/or the history of structural damage may often be determined based on the physical evidence. Normal wear and tear, aging, interaction with the elements, painting, repair work, etc. usually provide an historical documentation of the damage.
Let us look at a case study of cracking in a concrete driveway, as shown in Figures CR-1 thru CR-3. Note in the photographs that this cracking exhibits sharp edges and a fracture surface that is lighter colored that the concrete surface. Sharp-edges and the lighter colored fracture surface are indicative of a relatively recent occurrence, such as in this case study, an overload from the reported recent operation of an excessively heavy vehicle on the driveway.
Now look at other cracking in the concrete driveway, as shown in Figures CR-4 thru CR-6. Note that this cracking exhibits worn edges and a discolored fracture surface that matches the color of the driveway surface.
Worn edges and/or a discolored fracture surface are indicative of a cracking that has been present for years. The wear is due to erosion by wind, rain, freeze-thaw, foot traffic, vehicle traffic, etc. that has ground the sharpness off the concrete edge. The severity of the wear at the subject edge of the fracture indicates that this crack has been present for a period of time measured in years. Additionally, the similarity of the discoloration on the fracture surface to the discoloration of the pavement surface is due to the exposure of the fracture surface to sunlight, air, water, etc. for an extended period of time. The similarity between the coloring on the two surfaces indicates that the cracking has been present for a time period measured in years.
Finally, the cracked and worn patching material at some of the cracking also indicates that these have been present for a long period of time measured in years. If the time period of the patching can be documented by a witness of past photographs the age or history of the cracking may be more specifically determined. Similarly, conclusions about age and history may also be determined from physical evidences such as paint coverage, staining, adjacent remodeling, repair work, etc.
And sometimes, with the application of logic to the physical evidence, a chronological sequence of events and/or a more specific history or age may be determined.