TY - JOUR

T1 - Strengthening, lifetime extension, and monitoring of a deficient steel–concrete composite roadway bridge using iron-based shape memory alloys

AU - Vůjtěch, Jakub

AU - Ryjáček, Pavel

AU - Moshayedi, Hessamoddin

AU - Matos, Jose Campos

AU - Ghafoori, Elyas

N1 - Publisher Copyright: © 2024 The Authors

PY - 2024/11/15

Y1 - 2024/11/15

N2 - This study presents an innovative application of smart metals for the prestressed strengthening of roadway bridges. The target structure is a steel–concrete composite bridge, in which poor construction practices cause nonlinear creep, excessive deflection, and crack growth. However, the high flood water level of the creek below the bridge limits the application of conventional strengthening solutions. Therefore, an innovative strengthening method using iron-based shape memory alloy (Fe-SMA) bars for the post-tensioning of bridge members was designed and employed. The study framework encompassed the design, laboratory examination, installation, and monitoring of Fe-SMA reinforcements. A finite-element simulation was used to estimate the effect of applied prestressing on the stress distribution of the structure. High-cycle fatigue tests of Fe-SMA bars with different types of connections at room temperature and –20 °C, were conducted to select the most reliable connections. A total of approximately 825 m of Fe-SMA bars with a diameter of 18 mm, comprising 68 Fe-SMA bars, were installed and activated. A wireless sensor monitoring system consisting of strain gauges, potentiometers, linear-variable differential transformer sensors, and thermocouples was utilized to measure the changes in strain and stress of the designed system under field conditions. The results revealed a prestress loss of 8.5 % owing to relaxation after six months, which match well to the values obtained by the laboratory tests. A second static loading test was conducted approximately six months after strengthening, and the results indicated a 9 % reduction in mid-span deflection and a remarkable 106 % reduction in average stresses in the lower flange at the mid-span of the beams. The results of monitoring the bridge for a duration longer than 6 months highlighted a significant decrease in the mid-span deflection and indicated the potential of Fe-SMAs for the lifetime extension of bridges.

AB - This study presents an innovative application of smart metals for the prestressed strengthening of roadway bridges. The target structure is a steel–concrete composite bridge, in which poor construction practices cause nonlinear creep, excessive deflection, and crack growth. However, the high flood water level of the creek below the bridge limits the application of conventional strengthening solutions. Therefore, an innovative strengthening method using iron-based shape memory alloy (Fe-SMA) bars for the post-tensioning of bridge members was designed and employed. The study framework encompassed the design, laboratory examination, installation, and monitoring of Fe-SMA reinforcements. A finite-element simulation was used to estimate the effect of applied prestressing on the stress distribution of the structure. High-cycle fatigue tests of Fe-SMA bars with different types of connections at room temperature and –20 °C, were conducted to select the most reliable connections. A total of approximately 825 m of Fe-SMA bars with a diameter of 18 mm, comprising 68 Fe-SMA bars, were installed and activated. A wireless sensor monitoring system consisting of strain gauges, potentiometers, linear-variable differential transformer sensors, and thermocouples was utilized to measure the changes in strain and stress of the designed system under field conditions. The results revealed a prestress loss of 8.5 % owing to relaxation after six months, which match well to the values obtained by the laboratory tests. A second static loading test was conducted approximately six months after strengthening, and the results indicated a 9 % reduction in mid-span deflection and a remarkable 106 % reduction in average stresses in the lower flange at the mid-span of the beams. The results of monitoring the bridge for a duration longer than 6 months highlighted a significant decrease in the mid-span deflection and indicated the potential of Fe-SMAs for the lifetime extension of bridges.

KW - Bridge

KW - Iron-based shape memory alloy

KW - Lifetime extension

KW - Prestressed strengthening

KW - Recovery stress

KW - Strengthening

KW - Structural health monitoring

UR - http://www.scopus.com/inward/record.url?scp=85209100009&partnerID=8YFLogxK

U2 - 10.1016/j.engstruct.2024.119286

DO - 10.1016/j.engstruct.2024.119286

M3 - Article

AN - SCOPUS:85209100009

VL - 323

JO - Engineering structures

JF - Engineering structures

SN - 0141-0296

M1 - 119286

ER -