Structural performance of impact damaged and repaired concrete bridge girder using GFRP rebars

Abstract

Overpass bridge girders are susceptible to impact damage of over-height vehicles, creating a traffic hazard and structural deficiency. The repair for a damaged girder has to meet adequate criteria for the safety, repair time and economy. This paper presents a case study for the repair of such an impact damaged concrete girder on the Lyndon B. Johnson Express construction project, located on I-635 and I-35 freeways in Dallas, Texas. The impact caused concrete loss and exposed several prestressing strands on the exterior girder. The overpass had been completed while the old route was open below, causing a temporary vertical lower clearance than the final design, leading to the impact. The novel and innovative repair process involved fiber glass (GFRP) rebars, bonding epoxy and repair mortar. These rebars enhanced the flexural capacity of the repaired section and supplemented the mortar strength. Onsite load testing was employed to verify the performance of the repaired structure. Theoretical model of the composite girder before and after repair was employed. The strain data from the model compared well with the load testing data. The repair scheme drastically increased the stiffness of the damaged girder, resulting in about 50 % reduction in the bottom strains. The beneficial effect of the repair resulted in large increases in the net compressive stresses (200-300 %) at the girder bottom through the increase of the section stiffness and reduction of the gravity load stresses. Stresses remained well below the elastic range for concrete and the GFRP rebars.

Underpass clearance checking in highway widening projects using digital twins

“…The collision caused extensive damage to the precast/prestressed bridge girders, which led to the closure of the two-lane bridge. Yazdani and Montero [54] reported a bridge damaged from the over-height vehicles due to the existing underpass road remaining open and the temporary vertical lower clearance than the final design during the construction of the overpass bridge. Sometimes, long vehicles with low clearances could be stranded when attempting to pass rail-highway crossings with steeply graded profiles-hump crossings due to the combination of grade profile and cross-section interacting with unique vehicle dimensions.…”

Synthesis of Repair Materials and Methods for Reinforced Concrete and Prestressed Bridge Girders

“…(3) EB FRP soffit plates or strips [27,31,39,67,101,111,121,122,133,144,149,; (4) EB FRP plates on the girder soffit and sides with or without EB FRP U-wraps [63,126,211]; (5) NSM FRP strips or rods with or without EB transverse CFRP sheets [16,35,36,50,53,54,59,71,125,135,139,140,145,157,176,181,182,189,195,[212][213][214][215][216][217][218][219][220][221][222]; (6) embedded longitudinal and transverse GFRP bars [6]; (7) EB hybrid composites (FRCM, CRP, UHPFRC, etc.) on the soffit or wrapped around the girder bulb [17,19,…”

“…These factors make the repair and strengthening of bridge structures a crucial topic concerning all nations, which should be done efficiently and in an economic way. Some of the important factors in evaluating a proper repair method are safety, repair time, and economy [6]. Otherwise, in the absence of an economical and efficient repair technique, the bridge should be considered deficient.…”

“…The latter, however, can be referred to as a bridge that has inconsistencies with the current code requirements, such as narrow shoulders or lane widths, or inadequate clearance for oversize vehicles [ 2 , 3 ]. Common sources of damage to bridge girders are any of the following reasons or combinations of them [ 1 , 4 , 5 , 6 , 7 , 8 , 9 , 10 , 11 , 12 , 13 , 14 ]: (1) chloride attack, corrosion, and deterioration; (2) fatigue damage accumulation; (3) accidental damage such as overheight vehicle impact; (4) upgraded loading requirements and more stringent assessment codes; and (5) initial design flaws, construction defects, and a lack of maintenance.…”

“…Severe concrete spalling due to overheight truck impact damage[6], and example of lateral impact damage on steel reinforcement[24].…”