Strengtehning Residential Project

Project Overview

This project is situated in Lisbon, Portugal, and involves a high-rise residential building located in the city center. After the building had been in service for many years, subsequent adjustments to its functional use and increased floor loads resulted in insufficient load-bearing capacity within the original ribbed slab system and its primary and secondary beam components. Consequently, the floor slabs and beams exhibited structural cracks and excessive deflection, posing potential structural safety hazards. To enhance the structure's flexural load-bearing capacity—without increasing the self-weight of the components, encroaching upon interior usable space, or requiring a lengthy construction period—the owner and the design team ultimately opted to utilize 1.4mm-thick Carbon Fiber Reinforced Polymer (CFRP) plates for structural strengthening and reinforcement, thereby ensuring the safety and durability of the residential living environment.

Strengthening Plan

Target Elements: 

Closely ribbed slabs, as well as primary and secondary load-bearing beams (as illustrated in the ribbed floor system diagram). The strengthening measures specifically target the tensile zones located at the bottom of these flexural members.

Core Materials: 

1.4mm-thick continuous carbon fiber plates, utilized in conjunction with specialized carbon-plate anchor bolts, bonding epoxy adhesive, and leveling epoxy mortar. These carbon plates feature high tensile strength and a slim profile, making them ideally suited to meet the stringent requirements of residential buildings regarding floor-to-ceiling heights and interior finishing space.

Construction Process: 

Concrete substrate grinding and cleaning → Defect repair and surface leveling → Layout marking and positioning → Application of primer → Bonding of 1.4mm carbon plates → Securing with matching steel pressure strips and anchor bolts → Curing of the adhesive layer → Final inspection and acceptance. By leveraging the tensile properties of the carbon plates to substitute for—or supplement—the load-bearing capacity of the original steel reinforcement, this process effectively enhances the flexural load-bearing capacity of the structural members and controls deflection deformation.

Reinforcement Effects

Through reinforcement with 1.4mm carbon fiber plates, the flexural load-bearing capacity of the floor slabs and beams has been increased by over 35%; deflection and cracking have been effectively controlled, fully satisfying local Portuguese residential structural codes as well as long-term serviceability requirements.