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This article investigates a novel precast connection, with U-shaped bars extending from precast column to connect with the longitudinal bars in precast beams. To improve the seismic behavior of the connection, engineered cementitious composites, one kind of highly ductile concrete, were introduced into the core area of the connection, which also act as the cast-in-place material in the beam top and end. Prior to the test, finite element modeling was conducted to determine the proper splice length between U-shaped bars and beam reinforcements and also to evaluate the bonding performance of the proposed connection. The experimental program was then carried out on a monolithic connection, a precast connection with normal concrete as well as a precast connection with engineered cementitious composite, after which the seismic behaviors of the connections including their failure mode, hysteresis characteristic, stiffness degradation, ductility, and energy dissipation were analyzed. All three types of connections underwent typical flexural failure where the joint area remained intact. The negative carrying capacity, ductility, and energy dissipation were slightly lower for the connection with concrete, while the connection with engineered cementitious composite exhibited satisfactory behavior comparable to monolithic specimens. The latter connection with engineered cementitious composite is therefore suggested to be applied in highly seismic region.

To take full advantages of the bamboo and cold-formed thin-walled steel, a new type of box section beam combined with bamboo and steel channel was proposed in this paper. Five composite beams with different parameters were tested to evaluate the effects of bamboo plywood thickness of composite beams and thickness and sectional dimension of steel channel. The results of experiment showed that the proposed composite beams exhibited excellent flexural bearing capacities and stiffness. The increase of bamboo plywood thickness and sectional dimension of steel channel could improve bearing capacity and flexural stiffness of composite beams, while the increase of steel thickness could enhance the bearing capacity and safety margin of composite beams. Furthermore, a new method to predict the deformation and bearing capacities of composite beams was proposed and matched well with the experimental results.