Launch of Virtual Supports and Rigid Foundation by D.F.M. Perera. Published by Sarasavi Publishers. Price Rs. 850
Every engineer designing foundations gradually realises the limitations placed upon the exactness of the final product, from the envisaged mathematical model, intended or abstracted at the commencement of such a design.
This inexactness increases gradually from Pad-Combined-Strip-Raft in an ascending nature. While several geometrical attributes are altered to make the reality resemble the analytical model as closely as possible, there is no way to alleviate this disillusionment of being unable to create a back to back foundation design, such as it is, in the case of Superstructures.
The problem herein is in the fact that while engineers are capable of assessing the Loading Patterns of a Superstructure to a high degree of accuracy, they are unable to set the same degree of accuracy to the Soil Reactions acting upon foundations of such structures, although such Reactions are the result of that same Loading Pattern referred to above.
As a reflection of this difficulty, it is an established understanding that, while the many “Structural Analytical Computer Programmes” yield exact results for Superstructures of Buildings, Retaining Walls, Bridges and Silos - the foundation aspect of these are only an approximation, based upon the numerous assumptions that are forced upon the engineer, to achieve a tangible result.What Eng.D.F.M.Perera has done, has its real value in relieving the engineer of this - feeling of inexactness - by incorporating a pseudo condition in the analytical data that is fed into the computer, and thereby forcing the computer model to proceed as in the case of a Superstructure and yield a result that is highly compatible with the real Loading Pattern.
As said at the launching ceremony of the book, he has “provided a virtual system of statically determinate alternate supports to an existing system of forces already in equilibrium, while defining it to be of null value, so that the original equilibrium is undisturbed. Then the computer is forced to proceed and analyse it as a normal problem”.
Although the conceptual explanation of how this method works may sound complicated and baffling, the user of this method will find the tool suggested in his book through the various worked examples, to be very simple and forthright when in use.
This I believe is of paramount importance of any tool, becoming popular in its usage in the present day context.
On that note engineers who are faced with designing foundations will no doubt benefit from the use of this Extremely Simple Tool that has been named “Virtual Supports”, because it provides exact results, and thereby allows them to investigate the cost-effectiveness of each of their selected solutions for a particular foundation problem with ease.