Study On Seismic Behavior Of Row Lock Wall And Row Lock Wall Strengthened With HPFL

A thorough review is given to research status and development trend of seismicbehavior, reinforcement and finite element analysis of masonry structure. Based onthe test and finite element analysis, a study of row-lock cavity wall and its seismicperformance reinforced with HPFL strip is carried systematically.The masonry structure micro-model is studied. A three-dimensional finite elementmodel of double shear test of brick masonry specimen is established consideringbond-slip function of mortar and brick. As bond-slip relation of brick and mortar hasnot been studied in depth, bond-slip relation curves is proposed. Improved geneticalgorithm is presented, according to experimental results of double shear test. Andinversion program is compiled by APDL language, and parametric inversion ofbond-slip relation curves is implemented. The micro-model and bond-slip relationcurves are available to finite element analysis on masonry wall.Pseudo-static tests on twenty-four specimens of row-lock cavity wall and threespecimens of solid wall are conducted. According to experimental results of the wholefailure process, its failure mode and seismic performance indexes of shear capacity,hysteric curves, skeleton curves and ductility is dicussed.The row-lock cavity wall micro-model is studied. Based on the experimentalresults and finite element analysis, a systemically study of shear behavior effectfactors on row-lock cavity wall is conducted, such as brick-work mode, masonrymaterial strength, aspect ratio and vertical compressed stress. Shear behavior ofrow-lock cavity wall is affected by brickwork mode, but the impact is slight. In actualengineering, it is safe though disregarded. Material strength differs greatly on seismicbehavior of row-lock cavity wall. Both cracking load and ultimate load increase asmortar strength increased. The shear bearing capacity reduced as aspect ratioincreased. When N/Nu is less than0.6, shear bearing capacity and deformabilityincreases as vertical compressed stress increased. When N/Nu is more than0.6, thecapacity reduced as vertical compressed stress increased.According to Mohr-Coulomb theory, principal tensile and compressive theory,failure criteria of row-lock cavity wall is first proposed. The shear capability formulaof row-lock cavity wall is put forward.To analyze behavior indexes of wall failure mode, cracking load, ultimate load,hysteric curves, skeleton curves and rigidity degeneration, a series of pseudo-static tests on nine damaged row-lock cavity walls repaired by HPFL, nine undamagedrow-lock walls strengthened by HPFL, and three unreinforced comparison walls areconducted. The results indicates that HPFL helps to restore and improve seismicperformances of damaged row-lock cavity wall, and it helps to enhance wall ultimateload, improve ductility and rigidity degeneration of undamaged row-lock cavity wall.Finite element method of row-lock cavity wall separation-type model reinforcedwith HPFL is developed. Based on the experimental results and finite elementanalysis, a systemic study of reinforcement effect factors of band width reinforcement,mortar intensity reinforcement of surface course, steel fabric density reinforcement,masonry mortar’s strength, aspect ratio and vertical compressed stress are conductedrespectively. Band width reinforcement exerts great influences on HPFL stripreinforcement behavior, and width-broadening is the most effective to increase wallshear load. Wall shear load increases as the mortar intensity reinforcement of surfacecourse increased. Ultimate load increases slightly as steel fabric densityreinforcement increased, but the effect is not so big. Effects of HPFL enforcementdiffers in masonry mortar strengths, and a positive correlation between masonrymortar strength and HPFL enforcement effect on wall shear load is exited. Row-lockcavity wall of different aspect ratio strengthened by HPFL are confirmed to beeffective, though the aspect ratio effect is slight. Rowlock wall of different verticalcompressed stress strengthened by HPFL are confirmed to be effective, thoughmechanical principle of the HPFL reinforcement bands differs in vertical compressedstresses.The shear capability formula of row-lock cavity wall reinforced with HPFL stripis put forward.