125 / 2022-04-27 16:05:36

Unified stress-strain model for FRP-confined seawater sea-sand concrete

Seawater sea-sand concrete; FRP confinement; unified stress-strain model

In the construction of marine infrastructure, seawater and sea-sand can be used to replace fresh water and river sand to pour seawater sea-sand concrete (SSC), which makes rational use of marine resources, effectively reduces construction costs, and also saves fresh water and river sand. When SSC is confined by FRP (Fiber reinforced polymer), the excellent durability of FRP can avoid corrosion of the member, and meanwhile, SSC is in tri-axial compression and exhibits higher strength.



In this paper, unified stress-strain model for FRP-confined seawater sea-sand circular and square concrete columns is proposed based on the experimental database assembled from the published literatures. The database contains the test data of 318 uniform passively confined SSC circular columns and 30 non-uniform passively confined SSC square columns collected in 7 literatures. The concrete strength in the database ranges from 23.5MPa to 64.4MPa. The types of FRP are CFRP (carbon FRP) and BFRP (basalt FRP).The elastic modulus of FRP ranges from 44GPa to 257GPa and the thickness is from 0.15mm to 6.97mm. The proposed model can describe the axial stress-axial strain relationship of SSC under both uniform and non-uniform passive confinement and realize the unification of the two working conditions.



The behavior of the proposed model is verified by 9 FRP-confined circular specimens and 9 FRP-confined square specimens (e.g. Fig. 2). The average AAE (Average absolute error, AAE=sum (abs (Model result-Test result)/Test result)/n, Mean (Mean=sum (Model result/Test result)/n) and SD (Standard deviation) of the 18 specimens are 0.20, 1.00 and 0.27, and prove the good performance of the proposed model. The unified axial stress-axial strain model proposed in this paper can be used to predict the stress-strain relationship of uniform passively constrained seawater sea-sand concrete circular columns and non-uniform passively constrained seawater sea-sand concrete square columns and provide calculation basis for these FRP-confined concrete components.