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This study introduced a new design of the grouted corrugated duct connection (GCDC), which improves the structure integrity, bond strength and ease of constructability. A two-phase experimental program was performed to fully understand the connection behaviour. Phase I focused on the pull-out tests of 32 specimens in two batches with various conditions. It indicates that a connection length of 30 times of the rebar diameters would guarantee the bond strength. Phase II compared the 1/3-scale precast bridge column with its cast-in-place reference via quasi-static cyclic test. It showed that the precast column behaved similarly to that of the CIP column. [ABSTRACT FROM AUTHOR]

In this study, five 1/5-scale bridge girder specimens are tested with vertical quasi-static cyclic loading, in order to understand their performance in high seismic zones. The study is focused on the superstructures at two critical regions: (1) close to mid-span where high moments and low shears are present (2) and close to the supports where high negative moments and high shears are induced. The first case includes one precast segmental bridge box-girder, one precast segmental bridge I-girder, and one reference cast-in-place I-girder, while the second case consists of one precast segmental bridge I-girder and one cast-in-place I-girder. The ratios of the internal and external tendons are 1:1 for case 1 and 3:5 for case 2, respectively. Test results show that cast-in-place girders have better energy dissipation capacity and higher ultimate strength, but the precast segmental girders retain larger displacement capacity and self-centering capability. Internal post-tensioning tendons are subjected to more significant stress concentration at the joint locations of the precast segmental girders, while stress of external tendons is distributed more evenly. In terms of vertical loading, box-girder and I-girder possess similar hysteretic behaviors, as long as the effective widths are the same. [ABSTRACT FROM AUTHOR]

In this study, seven 1/3-scale bridge column specimens are investigated under the same quasi-static cyclic loading protocol both experimentally and numerically. The specimens consist of one cast-in-place (CIP) reference column and six precast columns. The precast columns are designed with different connection details, and they are tested for the feasibility study of the urban viaducts of highway S6 in Shanghai, China. The seismic performance of the precast columns needs to be investigated and verified prior to the practical application of these connection designs. Based on the experimental results, the precast specimens solely using mild reinforcement exhibit similar hysteretic behavior to the CIP reference column, though various grouted connection approaches are employed. The differences between these precast specimens and the CIP reference column are less than 15% for all indices. The precast specimens with bonded tendons (prestressing strands or prestressing bars) retain higher strength, but no less than 30% decrease of energy dissipation capacity is found. The bonded prestressing strands give at least 10% increase in strength compared with the CIP reference column, while the bonded prestressing bars provide approximately 50% improvement. The precast specimen utilizing unbonded tendon (prestressing strands) shows unique self-centering capability with equivalent energy dissipation capacity of the CIP reference column, but it has 33% lower ductility. Finite element modeling is performed and calibrated with the test data. Bond-slip behavior near column-to-footing interface is modeled by using a ZeroLength element at the interface. Buckling, fatigue and strength reduction of reinforcement are also considered in the model. Hysteretic behaviors of the specimens can be effectively simulated, and differences of ultimate strengths between the experimental and numerical results are less than 9%. [ABSTRACT FROM AUTHOR]

In this study, quasi-static cyclic test was conducted for three 1/3-scale specimens of different precast concrete frame pier structure systems of an urban viaduct in Shanghai, China. Various connection deployment strategies were utilized for the specimens, in order to verify these precast concrete frame piers used in the real structure. Two of the specimens were of the same cap beam design, while the third one was with tie beam. The two frame piers with cap beam had the same column-footing connection (grouted splice sleeve coupler), but the column-cap connections were grouted splice sleeve coupler and grouted corrugated duct connection, respectively. The frame pier with cast-in-place tie beam, however, only kept the grouted splice sleeve coupler for column-footing connection. The cyclic test results showed similar seismic behavior of the two specimens with cap beam, whereas the specimen with tie beam exhibited less energy dissipation capacity. This indicated that the seismic performance differences among the specimens are mainly caused by different structure systems, and the two types of the connections behave similarly with little damage. Finite element models that were optimized by considering joint region behavior and bond-slip phenomena showed good agreement with the test results. [ABSTRACT FROM AUTHOR]