A buckling resistant spring clad bar (BRSCB) assembly is described. The BRSCB assembly includes a plurality of bars arranged to form a perimeter, each of the plurality of bars having a top end and a bottom end. A plurality of springs are provided, wherein at least one of the plurality of springs is wrapped around each of the plurality of bars. A diameter of the at least one of the plurality of spring is greater than a diameter of the each of the plurality of bars. The at least one of the plurality of springs is wrapped around each of the plurality of bars in close contact to provide buckling resistance against a load applied over each of the plurality of bars.

There is provided a method of prestressing a beam-column joint with an appropriate ratio among the magnitudes of compression in the directions of X, Y, and Z axes. The method introduces prestress in a beam-column joint with a tensile introducing force generated by tensionally anchoring prestressing tendons that are arranged in PC beams extending along two horizontal directions (or X axis and Y axis) and PC columns extending along the vertical direction (or Z axis) and passed through the beam-column joint to bring the beam-column joint in triaxial compression, the prestress being introduced such that a diagonal tensile force T generated by an input shear force due to a seismic load of an extremely great earthquake that may occur very rarely will be cancelled completely or partially so as not to allow diagonal cracks to occur. The ratio of the prestresses introduced in the directions of the respective axes satisfies the following equation (1):

x:y:z=1:1:0.30.9 (1)

where x, y, and z are prestresses introduced in the directions of the X axis, the Y axis, and the Z axis respectively.

Disclosed is a buttress assembly located outside side walls comprising non-bearing walls located in a long side direction of an existing building and comprising concrete, the buttress assembly including a plurality of reinforcing steel structures extending in a short side direction of the existing building, connected to the existing building by anchors, and arranged in a vertical direction of the side walls.

A polymer-modified hybrid-fibers cementitious composition has a one-day compressive strength of at least approximately 17 MPa, a 28-day tensile strength of at least approximately 3.8 MPa, an ultimate tensile strain of approximately 3% to approximately 9%, and a 7-day bond strength of at least approximately 2.3 MPa. A binder of ordinary Portland cement, fly ash, and silica fume is provided. Other components include limestone powder, sand, superplasticizer, and water. The composition further includes one or more of styrene butadiene rubber or ethylene-vinyl acetate copolymer in an amount ranging between approximately 2% and approximately 8% by mass of binder. Fiber additives include steel fibers in an amount ranging between approximately 0.3% and approximately 3.0% by volume of the cementitious composition and polymer fibers in an amount less than approximately 1.0% by volume of the cementitious composition. Chamfers made of the composition are positioned at beam-column joints.

Precast construction elements are described suitable for use in high seismic area. The precast construction elements can be precast, pre-topped double tees. The precast construction elements incorporate a passive energy dissipation device in a flange. The energy dissipation device provides a ductile connection having a deformation capacity of larger than 0.6. Adjacent elements are connected to one another at joints that include the passive energy dissipation device. Passive energy dissipation devices can be passive hysteretic dampeners, such as U-shaped flexural plates. Passive energy dissipation devices can be bar dissipaters (e.g., grooved dissipaters). Also described are passive hysteretic dampers that include U-shaped flexural plates held in conjunction with a reinforcement element that defines a circle around which the flexural plate can bend.

Although Fiber Reinforced Polymers (FRPs), as alternatives for the corrosive steel reinforcement in concrete structures, have shown promising performance under gravity loads, their performance under reversal cyclic loading is still one of the main concerns. The linear behavior of FRP reinforcement has a two-sided effect on the seismic performance of FRP-reinforced concrete (RC) moment-resisting frames. Although the linear nature of FRP reinforcement could be advantageous in terms of limiting the residual damage after an earthquake event, it lowers the energy dissipation of the structure which can compromise its seismic performance. Disclosed herein is the addition of steel plates at selected locations in moment-resisting frames to improve seismic performance of FRP-RC structures while still being able to take advantage of its linear behaviour (minimal residual damage after earthquake). The effectiveness of the proposed solution was tested both experimentally and analytically.

An n-shape connected split column for underground structure comprises a prefabricated reinforced concrete column, n-shape connector, exterior packaged steel sheet, reserved connecting reinforcement and reserved high strength bolt. The subject of the prefabricated reinforced concrete column is an ordinary reinforced concrete column; the reserved connecting reinforcement is reserved on the top and bottom of the prefabricated reinforced concrete column; a high strength bolt is reserved on adjacent side faces. The n-shape connector connects with prefabricated reinforced concrete column through reserved high strength bolt; they are installed in underground structure through reserved connecting reinforcement. The exterior packaged steel sheet is pasted on the exterior of the prefabricated reinforced concrete column, and coadjacent prefabricated reinforced concrete column and connection gap between them is overall packaged to ensure the performance of split column under normal service condition. The present disclosure has clear concept and principle; it is easy to be manufactured, repaired, and installed in a key position of underground structure to decrease the damage of earthquake for an underground structure.

A polymer-modified hybrid-fibers cementitious composition has a one-day compressive strength of at least approximately 17 MPa, a 28-day tensile strength of at least approximately 3.8 MPa, an ultimate tensile strain of approximately 3% to approximately 9%, and a 7-day bond strength of at least approximately 2.3 MPa. A binder of ordinary Portland cement, fly ash, and silica fume is provided. Other components include limestone powder, sand, superplasticizer, and water. The composition further includes one or more of styrene butadiene rubber or ethylene-vinyl acetate copolymer in an amount ranging between approximately 2% and approximately 8% by mass of binder. Fiber additives include steel fibers in an amount ranging between approximately 0.3% and approximately 3.0% by volume of the cementitious composition and polymer fibers in an amount less than approximately 1.0% by volume of the cementitious composition. Chamfers made of the composition are positioned at beam-column joints.

The column-base joint includes a prefabricated-reinforced-concrete column and a reinforced-concrete foundation, and further includes a coating-steel-plate sleeve that is integrally prefabricated with the concrete column and encloses an exterior of a column base. A gap is between a bottom end of the coating-steel-plate sleeve and an upper surface of the foundation. An outside of the gap is provided with a plugging material. The joint further includes an annular rib plate all of whose edges are horizontally and seamlessly connected to an inner wall of the coating-steel-plate sleeve and whose middle portion is provided with a rib-plate opening. The annular rib plate is provided with a sleeve opening that matches with the grouting sleeve device.

The joint has a prefabricated-reinforced-concrete column, a reinforced-concrete foundation, a column anchoring longitudinal bar, a grouting sleeve and a foundation anchoring steel bar. The foundation anchoring steel bar and the column anchoring longitudinal bar are connected by a seam filling material filling the grouting sleeve. A splicing seam between the reinforced-concrete foundation and the prefabricated-reinforced-concrete column is filled with the seam filling material. The foundation anchoring steel bar includes a vertical portion and a horizontal portion. The vertical portion includes an upper-portion anchoring section protruding out of an upper surface of the reinforced-concrete foundation, a middle-portion non-adhesive section buried within the foundation and a lower-portion anchoring section. An exterior of the middle-portion non-adhesive section is provided with an isolating sheath for isolating the middle-portion non-adhesive section and the concrete adhesion.