We were discussing about tolerances in concrete construction. In the previous post, we have listed factors that influence tolerances; now we will discuss each factor:
a. Structural function and strength requirements
The structure should be strong and sufficient safety is provided which reflect design assumptions. The shape and size should be accurate enough for the job to satisfy design and construction requirements.
The structure should satisfy expectation of owner and designer as well satisfying all requirements of appearance.
c. Economic feasibility:
The cost of construction or any precast/prestressed products depends largely on tolerance limit. Construction method is also equally important. It is obvious that tight tolerance associated with higher cost involvement.
d. Relationship of components
The tolerances provided in construction may be for individual part or for global structure. In case of individual tolerance, it depends on following terms of adjacent parts:
1. Materials of adjacent units
2. Connection and joint details
3. Applicability of tolerances into critical dimensions
e. Construction techniques
The feasibility and practicability of specific tolerance, in this regard, depends on
f. Material properties
In prestress member, camber is a well know term and shrinkage is a global term in concrete members. In determining deflection in design stage difficulties arisen by these two term and should be considered while determining tolerances.
Compatibility between architectural details and expectation of finish should be fixed based on expected construction method. The relation between two should include in the tolerances in concrete construction.
h. Job conditions
This factor includes job conditions and situations. Clear specifications should be provided from design office where sensitive tolerances are required that represents requirements of project site.
Some bench marks and control points are provided as a reference to verify tolerances of different parameters. This are achieved by mutual understanding and they are maintained undisturbed until final acceptance and completion of project.