The main purpose of this study was to investigate and implement a repair design for corrosion damaged bridge bents in order to resist lateral loading, such as wind loads or ship impact. Using the results from a one-third scale bridge bent constructed and tested for a previous study, non-linear modeling was used to simulate the same corrosion damage and load response. The principle variable considered was damage, represented as a percent of effective area loss of prestressing steel within a designated damage zone along the length of piles. Other influencing variables included: prestress transfer length, localized loss in prestress due to corrosion damage, prestress force, and concrete modulus of elasticity. Upon successful convergence of measured and modeled results, carbon fiber repair schemes were then modeled to restore bents to their full capacity. Suitable repairs were judged on the basis of restoration of capacity of the entire pile bent and the interaction diagrams of the individual piles. Results of the modeled repairs suggested that a single layer of a commercially available unidirectional carbon fiber would be sufficient when aligned longitudinally. No benefit from accompanying transverse fibers were considered although such a repair was suggested by the study findings. Analysis indicated that longitudinally bonded carbon fiber reinforced polymer (CFRP) to bridge piles increases a bent’s ability to resist bending moment due to lateral loading at the cap. However, additional capacity to plastic region of the response curve indicated larger capacity gains than by gains to elastic regions.

Yes / Eccentric compression behaviour of reinforced concrete (RC) columns reinforced by steel-FRP composite bars (SFCBs) was investigated through experimental work and theoretical analyses. The tension and compression test results show that SFCBs demonstrate a stable post-yield stiffness. The mechanical properties of the composite reinforcement have a significant influence on eccentric compression behaviour of the reinforced concrete columns, in terms of failure mode, crack width, deformation and bearing capacity. Formulae were also developed to discriminate failure mode and to determine moment magnification factor, bearing capacity and crack width of the columns studied, with the theoretical predictions being in a good agreement with the experimental results. In addition, parametric studies were conducted to evaluate the effects of mechanical properties of reinforcement, reinforcement ratio, eccentricity, slenderness ratio, types of reinforcement and concrete on the eccentric compression behaviour of RC columns. The results show that the compressive performance is significantly improved by using the high performance concrete, i.e. reactive powder concrete (RPC) and engineered cementious composites (ECC). / financial supports of the work by the National Natural Science Foundation of China (51678514), the Natural Science Foundation of Jiangsu Province, China (BK20201436), the China Postdoctoral Science Foundation (2018M642335), the Science and Technology Project of Jiangsu Construction System (2018ZD047), the Deputy General Manager Science and Technology Project of Jiangsu Province (FZ20200869), the Cooperative Education Project of Ministry of Education, China (201901273053), the Blue Project Youth Academic Leader of Colleges and Universities in Jiangsu Province (2020), the Six Talent Peaks Project of Jiangsu Province (JZ-038, 2016), the Yangzhou University Top Talents Support Project and the Jiangsu Government Scholarship for Overseas Studies.

The lateral resistance of pile foundations is typically based on the performance of round piles even though other pile types are used. Due to lack of data there is a certain level of uncertainty when designing pile foundations other than round piles for lateral loading. Theoretical analyses have suggested that square sections will have more lateral resistance due to the increased side shear resistance, no test results have been available to substantiate the contention. Full-scale lateral load tests involving pile shapes such as circular, circular wrapped with high density polyethylene sheeting, square, H, and circular with a corrugated metal sleeve have been performed considering the influence of soil-pile interaction on lateral load resistance. The load test results, which can be summarized as a p-y curve, show higher soil resistance from the H and square sections after accounting for differences in the moment of inertia for the different pile sections. The increased soil resistance can generally be accounted for using a p-multiplier approach with a value of approximately 1.25 for square or 1.2 for H piles relative to circular piles. It has been determined that high density polyethylene sheeting provides little if any reduction in the lateral resistance when wrapped around a circular pile. Circular piles with a corrugated metal sleeve respond to lateral loading with higher values of lateral resistance than independent circular piles in the same soil.

An analytical model for lateral deflection in cold-formed steel shear walls sheathed with steel is developed in this research. The model is based on the four factors: fastener displacement, steel sheet deformation, and hold-down deformation, which are from the effective strip concept and a complexity factor, which accounts for the additional influential factors not considered in the previous three terms. The model uses design equations based on the actual material and mechanical properties of the shear wall. Furthermore, the model accounts for aggressive and conservative designers by predicting deflection at different shear strength degrees.

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