Reasons for insufficient concrete strength and methods to solve the accident in construction

A certain market is a four-storey frame structure.The insufficient concrete strength of beam-slab-column was checked out in construction process.According to the strength test data of the resilience and cored samples of the concrete and the detection report of the cement soundness and retarded water-reducing,the cause of insufficient concrete strength was analyzed.Finally,the reinforcement plan was put forward.The construction ran well in the past few years.