Should Project Manager communicate with site ENGs ,Foremen and Labors , or He should only deal with Engineers in next row of organizational structure?

Project Manager shall communicate with Engineers to maintain the relations healthy between the engineers and foremen and labors. 

However, during site visit PM must pay attention to foremen and labors to encourage their work, that will build the trust in them and they will work honestly and give more productivity.

he should be involved with all of his employees but with conditions ...here are some

1- the involvement shouldn't touch any of of his employees's authorities

2- it should not be on personal base....if any ...it should be out of work place and working times

3- he should be clear about the chain of command and the authority schedule 

4- he should keep in mind that even though we are human and must have human relations,,,,but we are here for one thing....getting the job done as professionally as we can

5- he must take care of some kind of people who can misuse his friendly involvement

Thank you very much for the invitation and sorry I do not have any knowledge/experience about civil engineering. Let me try to answer with the little knowledge I have about project management in IT systems. 

I think there is nothing wrong in communicating in down the line to get the work done in efficient and expedite manner, but micro management may not be much helpful. Thanks.

That is depend on project volume .In big project , we use "the hierarchy structure" in process of project managing , so the commands have been taken from the project manager will pass from the top to the down of the hierarchy of project management staff. 

Thus, successful project management is dependent on the effective team building skills. A project management hierarchy can be defined as a list, in which various professionals are being ranked from top to bottom, in accordance with their job responsibilities and their significance to the whole project.

A project management hierarchy has lots of advantages for the organization. With the help of the hierarchy, it is being possible to determine the sequence of tasks, determine the expectation of each and every level of the project team and also to schedule the projects.

PM should give to his next row opportunity to manage their roll ( Authority & Responsibility), just in emergency events he can allow himself to interfere and take over the whole responsibility to be interfering.

In my point of view, the project manager should only communicate with the site manager and engineers only regarding technical and progress matters. On the other hand he should open his door for project team members discussions, as well as he should be eager to keep periodic coordination meeting with all team members.

 Project Manager Should be aware with Site circumstances   & Problems by Regular Visits and  .

communicating with site Engineers,forman and labors  

 But he should also away from Site circumstances & Problems by his interference 

Except for very BIG Problems because the centralization is not good in project management 

all the colleagues and staff are stockholders and creating a good environment help to gain more.  therefore communication management is one of the most important part of proj. manager tasks.

but the PM must be aware of emerging mass communication or conflict between the staff. it means he should be skilled in selecting medias or messages to communicate with others.

The Project Manager must bring his project to completion, and he is the only person fully responsible for it. So he should do anything not breaching law to reach his goal.

The Project Manager, first of all, is a person. So why should he neglect the people of lower status? Sometimes, direct communication with foreman makes him to understand the job task. However, there is no need to spend all the time to such communications, and the PM should balance time and distance himself.

I agree with Mr. Ahmed Saad Eldin Elkasass, the project manager should limit his communication with the site engr., foremen, labors because it may result to problems in the organization. Sometimes, these people will have the confidence to report to the project manager, ignoring their immediate supervisors or superintendents on the job. This will create a gap on the relationships of the organization. However, for big issues, the project manager shall give inspirational talks and motivate the workers to follow their immediate superiors. As they say, good organization is created thru the cooperation of the members and will results to success of the project.