A rebar support chair has a housing with first and second opposed boundary walls spaced apart from one another and defining a cavity therebetween, an attachment portion having a seat for supporting rebar, a dampening member, and a force dispersion member inside the cavity. The attachment portion transfers forces between the rebar and housing. The force dispersion member moves in response to vibration of the attachment portion, and movement of the force dispersion member corresponds with compression and decompression of the dampening member. Another rebar support chair has a housing defining a cavity, an attachment portion for supporting rebar, a dampening member, and a force dispersion member in the cavity. The attachment portion transfers forces between the rebar and housing. The force dispersion member moves from a rest position in response to vibration of the attachment portion, and the dampening member biases the force dispersion member toward the rest position.

PROBLEM TO BE SOLVED: To provide a concrete structure and a concrete slab, which, by using a continuous fiber-reinforced polymer material as a main reinforcing material or a tendon, and by mixing a short fiber reinforcing material in concrete, compensate for the mechanical shortcomings of the continuous fiber-reinforced polymer material, not rusting, and taking advantage of superior characteristics of the continuous fiber-reinforced polymer material, with low manufacturing cost and ultra-high durability.

MEANS TO SOLVE THE PROBLEM: In a concrete structure, in which a continuous fiber-reinforced polymer material is arranged as a main reinforcing material or a tendon, a short fiber reinforcing material consisting of an organic fiber is mixed in 0.5% or more with respect to an entire volume, the continuous fiber-reinforced polymer material is shaped like a rod or a stranded wire, a ratio Lf/Gm between a fiber length Lf of the organic fiber of the short fiber reinforcing material and a maximum aggregate diameter Gm of a concrete composition is 1.2 to 3.7, and an aspect ratio Lf/De when an equivalent diameter De, which is a cross-sectional area of the organic fiber converted into a circle diameter, is 30 to 69.

Fiber reinforced plastic (FRP) sheet or jacket systems and methods are provided as an alternative splicing method to connect driven pile segments or other structural members. These systems are applicable to both unforeseen and preplanned splicing situations and can be used in the unforeseen condition when other splice systems may fail to provide the required capacity.

Fiber reinforced plastic (FRP) sheet or jacket systems and methods are provided as an alternative splicing method to connect driven pile segments or other structural members. These systems are applicable to both unforeseen and preplanned splicing situations and can be used in the unforeseen condition when other splice systems may fail to provide the required capacity.

A system for centering a reinforcing member within a drilled shaft/bore hole includes a first cage member and a second cage member. The first cage member is operable to surround a first half of the reinforcing member. The second cage member is operable to surround a second half of the reinforcing member. The second cage member is operably connected to the first cage member, and the first and second cage members have identical shapes.

The present disclosure provides a concrete structure strengthened using a grid reinforcement material and non-shrink grout and a method of strengthening the same in which, when strengthening a concrete structure such as a concrete slab or a concrete wall body that is damaged or deteriorated, a grid reinforcement material is mounted on one side of the concrete structure, a formwork is formed on an outer side of the grid reinforcement material to have a required gap, and then the gap is filled with non-shrink grout so that the non-shrink grout is cured therein to strengthen the old concrete structure, thereby being able to automatically fill and repair cracks formed in the concrete structure just by injecting the non-shrink grout without separately performing crack repair on the old concrete structure. Also, the grid reinforcement material may be easily fixed or mounted using a grid fixing device and may be easily applied to strengthening of a concrete structure having a curved surface as well as a concrete structure having a flat surface such as a concrete slab or a concrete wall body. In addition, reinforcing bars may be additionally arranged in a gap between a surface of the concrete structure and the grid reinforcement material so that the grid reinforcement material increases a cover thickness, and thus the concrete structure is remarkably strengthened.

The present disclosure provides a concrete structure strengthened using a grid reinforcement material and non-shrink grout and a method of strengthening the same in which, when strengthening a concrete structure such as a concrete slab or a concrete wall body that is damaged or deteriorated, a grid reinforcement material is mounted on one side of the concrete structure, a formwork is formed on an outer side of the grid reinforcement material to have a required gap, and then the gap is filled with non-shrink grout so that the non-shrink grout is cured therein to strengthen the old concrete structure, thereby being able to automatically fill and repair cracks formed in the concrete structure just by injecting the non-shrink grout without separately performing crack repair on the old concrete structure. Also, the grid reinforcement material may be easily fixed or mounted using a grid fixing device and may be easily applied to strengthening of a concrete structure having a curved surface as well as a concrete structure having a flat surface such as a concrete slab or a concrete wall body. In addition, reinforcing bars may be additionally arranged in a gap between a surface of the concrete structure and the grid reinforcement material so that the grid reinforcement material increases a cover thickness, and thus the concrete structure is remarkably strengthened.

A concrete structure includes a continuous fiber-reinforced polymer material arranged as a main reinforcing material or a tendon. A short fiber reinforcing material consisting of an organic fiber is mixed in 0.5% or more with respect to an entire volume. The continuous fiber-reinforced polymer material is shaped like a rod or a stranded wire. A ratio Lf/Gm between a fiber length Lf of the organic fiber of the short fiber reinforcing material and a maximum aggregate diameter Gm of a concrete composition is 1.2 to 3.7, and an aspect ratio Lf/De, in which De is an equivalent diameter that is a cross-sectional area of the organic fiber converted into a circle diameter, is 30 to 69.

A concrete structure includes a continuous fiber-reinforced polymer material arranged as a main reinforcing material or a tendon. A short fiber reinforcing material consisting of an organic fiber is mixed in 0.5% or more with respect to an entire volume. The continuous fiber-reinforced polymer material is shaped like a rod or a stranded wire. A ratio Lf/Gm between a fiber length Lf of the organic fiber of the short fiber reinforcing material and a maximum aggregate diameter Gm of a concrete composition is 1.2 to 3.7, and an aspect ratio Lf/De, in which De is an equivalent diameter that is a cross-sectional area of the organic fiber converted into a circle diameter, is 30 to 69.

An anchor for supporting a reinforcing mesh includes an elongated bar having a predetermined length. A cap is mounted on the elongated bar and includes a mounting section with an opening for receiving the elongated bar and a clip section extending from a side of the mounting section and including a flexible slot configured to receive a section of a reinforcing mesh therein.