If the employer believes that changing the shape, quality, or quantity of the work or some part of it is appropriate, he has the authority to order the contractor to do so. These instructions would extend the time it takes to accomplish the task and, as a result, the project's completion time. In the majority of situations, the employer and the contractor couldn't agree on how to compute the extra time the contractor was provided as a result of change orders. The aim of this research is to find a mechanism to determine the additional time required to carry out these works, which will vary based on the type of work, the increase in quantity for any work within the contract, etc.. Modify the nature, quality or type of any work, change the levels, lines, position and dimensions of any part of the work, and perform any additional work necessary to finish the works. A field visit and survey will be conducted on the various bridge projects as part of the research to determine the types of change orders and the additional time required for each of them, in addition to the most important reasons for not using the relative change length and how each project differs from the other. Mathematical software can be enhanced to reliably calculate the additional time for each form of change order. Most of the works expected to appear in variation order are steel and concrete works, and asphalt cladding works, with a frequency of each of them (25 percent), followed by excavation works, which have a frequency of (16.66 percent) in bridge projects.
The maintenance operation of complexes and the direction of it is management is considered the most important activities which must be given much more efforts and seriousness because of it is considered the national resource and is to save the best ways of living equally all social classes in addition to it considered one of modern and civilized appearances. The paper deals with field study of the town with (2800) housing units with various and complete service units through shedding the light on the real work of the organization runs maintenance in the technical and administrative fields as well as appointing the weak point and finding the best way to handle by developing the existing maintenance order . The proposed development focusing on the following: •The periodic maintenance with some general terms (checking and evaluation) the best means to control defects.•The administrative operation elements in the organization especially the regulation and planning. •Saving the necessary financial resources to carry out the activities of various maintenance. •The importance of limiting the priorities in the work. •Trying to practices new subject in dealing with employees in simple and polite way and create anther image of collection management. Therefor, we draw conclusion of the beneficiary of these systems actively to develop the complexes maintenance system in all over the country by making the suitable amendment for every case.