Fiber reinforced composite system for strengthening of wall-like RC columns and methods for preparing such system

Patent metadata

Field	Value
Publication number	US-9580908-B2
Application number	US-201414539038-A
Country	US
Kind code	B2
Filing date	Nov 12, 2014
Priority date	Nov 12, 2014
Publication date	Feb 28, 2017
Grant date	Feb 28, 2017

Abstract

A shape modification of a wall-like column includes the preparation of the column by chamfering the corners and roughening the sides of cement segments thereto. The process requires a simple formwork in the form of generally circular PVC pipe segments which are cut to required shapes which are arcuate such as the segments of a circle, oval or even elliptical. After those forms formed from the PVC pipe affixed around the reinforced concrete column are then filled with grout/cement. A plurality of vertical steel strips are attached to the column by steel rod-like shear studs that extend through previously drilled passageways passing through the reinforced concrete column and segments. The reinforced concrete column is then strengthened by increasing the area of cross section and more importantly by confining the column and attached segments by FRP materials. In addition, the vertical strips with steel studs contribute to the column strengthening.

First claim

What is claimed is:

1. A fiber reinforced polymer composite structure comprising:
a reinforced concrete column having a rectangular cross section with a top, a bottom, two opposite sides and two ends and an aspect ratio of 1.5:1 (length of sidewalls to thickness between the sidewalls) or greater, chamfered corners, and two or more arcuate cement segments disposed on each of said two opposite sides of said column and a single segment disposed on each of said ends;
a fiber reinforced polymer material surrounding said column and said segments;
one or more perpendicular passages perpendicular to and through said fiber reinforced polymer material between adjacent segments on each of said opposite sides of said column; and
a steel bolt extending through each of said one or more passages and a nut for fastening said column, said segments or segment and said fiber reinforced polymer together under compression;
in which each of said arcuate cement segments form a portion of a generally circular shape on said reinforced concrete column; and
wherein an arcuate segment on each of said ends with an adjacent arcuate segment on each of said sidewalls form a semicircular shape abutting the two side and an end, and wherein the arcuate cement segments at the end are continuous over the reinforced concrete column and cover said chamfered corners at a predetermined depth.

2. The fiber reinforced polymer composite structure according to claim 1 , in which a nut is attached to each of said bolts for fastening said column, said segments and said fiber reinforced polymer together under compression; and wherein for rectangular columns with a cross section of a×b with a>the diameter of the end circular bulb D may be taken as b+2c wherein c is the maximum permissible column offset from the longer side of the column cross section.

3. A method for strengthening rectangular reinforced concrete (RC) columns by shape modification using fiber reinforced polymer materials (RPM), said method comprising:
surrounding a rectangular reinforced concrete column with a plurality of plastic pipe segments forming one or more arcuate segments surrounding said column with a plurality of said segments on opposite sides thereof and in contact therewith;
filling voids formed between said arcuate plastic pipe segments and said column with grout;
hardening said grout form arcuate cement segments and wrapping said hardened segments and said column with fiber reinforced polymer materials (RPM);
forming one or more passageways through said column, said arcuate cement segments and said fiber reinforced polymer materials (RPM);
providing a steel bolt and steel nuts on opposite sides of said column for passing said steel bolt through said passageway and with said steel nuts on opposite sides of said column; and
fastening steel studs on opposite sides of said column to hold said column, arcuate cement segments, and fiber reinforced polymer materials (RPM) together under compression; and
wherein the diameter of the arcuate cement segment is based on the following formula

D
=

b
2

+

[

a
n

-

u
⁡

(

1
-

1
n

)

]

2

wherein n=number bulbs; u=clear distance between adjoining mortar bulbs which is slightly more than the width of a vertical steel strip between the adjoining bulbs due to the thickness of FRP sheet and the value of maximum column offset c is determined using c=(D−b)/2 assuming the same distance of each bulb and the same magnitude of maximum column offset for each bulb.

Assignees

• Univ King Saud

Inventors

• Al-Salloum Yousef A
• Abbas Husain
• Alsayed Saleh H
• Siddiqui Nadeem A

Classifications

• E04C5/01

  Reinforcing elements of metal, e.g. with non-structural coatings {(E04C5/08 takes precedence)} · CPC title

• E02D5/60

  Piles with protecting cases · CPC title

• E04C5/073

  Discrete reinforcing elements, e.g. fibres · CPC title

• E04C3/34 Primary

  of concrete other stone-like material, with or without permanent form elements, with or without internal or external reinforcement, e.g. metal coverings (E04C3/36 takes precedence) · CPC title

• E04C3/36

  of materials not covered by groups E04C3/32 or E04C3/34; of a combination of two or more materials · CPC title