Structures may be subjected to a local loss of soil support under some oftheir footings due to several factors such ~s adjacent excavation for a newneighbor foundation, increasing the load on the surrounding soil, erosion byground water and compaction resulting from vibrations due to-pile driving,./traffic and earthquakes. The previous factors may cause excessive differentialsettlements and even failures of an existing building. ’The aim of this thesis. is to investigate theoretically and experimentallyusing finite element and photoelasticity techniques the behavior of multi storyframes supported” by continuous strip footing and resting on elastic half spacemedium when an edge loss of soil support underneath the footing takes place.Local loss of soil support may cause an increase in the internal forces inthe superstructure frames beyond the allowable values. It may also cause anincrease in the internal stresses ID the footing beyond the allowable valuesconsidered in the design, which may cause cracks, or failure of existingbuildings. Therefore analysis of soil-structure interaction with a loss of soilsupport is of fundamental importance to both structural and geotechnicalengmeenng.This thesis presents a three-dimensional finite element approach as acontribution to meet the need for treating the superstructure, foundation and thesupporting soil as parts of a single continuous system.The results for the case of no loss of soil support and the different cases ofloss of soil support will be compared. The results obtained form finite elementand the second bid price is called ”The money left on thetable” (M.L.T.). The literature of this subject has beencritically reviewed. The data from 917 bids were collected,organised and analysed. These data were then used toinvestigate and analyse the following: ,- The quantification of the money left on the table.- The factors affecting the (M.L.T.) and the consequence.- The relationships between the lowest, the average and thehighest bid prices.- The variations that exist among all bids submitted for atender.The data were also used to study the relationshipsbetween the money left on the table and some factors, such as:Type of projects, number of competitors, contract valueetc. The relationships between the variation of bids and thefactors affecting this variation were also studied.The results showed that the average money left on thetable was 9.91\ from the lowest bid price. The average numberof competitor per tender Is 5.5. The lowest bid price was 77%of the average bid pr ice, whi le the highest bid pr ice was· 29%higher than the average bid price. Consequently, the highestbid price was 1.7 times the lowest bid price. The results alsoshowed that the average coefficient of variation was 14.5%.This study would be of benefit for both contractors andowners. It highlights the mechanism of competitive bidding forthe construction managers of all levels, and helps them toevaluate the situation of their companies, competitors, or ofthe construction industry as a whole.