Fissure analysis in one-directional slabs with on-site concrete rib by continuous formwork

This article presents a detailed analysis of a common pathology in concrete one-directional slabs with on-site rib and prefabricated concrete hollow blocks. This pathology is causing complaints from the users and tenants of the buildings affected by it pressing charges against the construction companies.This pathology consists of very thin fissures marked on the claddings, and parallel to the slab ribs. The cracks usually begin to be detected a few days after the slab is in service, after partitions and floor paving are placed and they normally appear much quicker in dry and warm weather. These fissures occur in isolation and are distanced according to the width of the slab. In addition, although the cracking lines show an apparent fixed repetition, there does not seem to be a correlation between this modulation and the frame geometry/modulation.This work analyzes the causes for this pathology type proposing some solutions to avoid it.