RETROFIT/STRENGTHENING OF BUILDINGS

The application of unidirectional sheet-type materials is attractive for the retrofit/strengthening of structural components in buildings because the materials can be easily installed in limited areas and close spaces without need for significant changes to the structure in preparation. This causes minimum distress to the occupants of the building. Furthermore, since the material is resistant to corrosion, and inert to most influences (in the case of carbon) it is virtually maintenance free. It can be overlaid or covered by decorative coatings/finishes without concern about future continuous access.

Between 1987 and 1995, of a total of 615 structures retrofitted using Mitsubishi Chemicals Replark Sheet, about 59.3% was related to buildings. In 1995 about 12% of sales of Tonen's FORCA tow sheet was in the area of buildings. A significant percentage of Toray's Torayca cloth is also reportedly used for the same application. There has also been some limited use of the aramid fiber based FITS system for the retrofit of building components. These systems have been used for a variety of structural elements such as the seismic retrofit of internal building columns (Figs. 4.29 and 4.30), repair of cracked apartment floorboards (Fig. 4.31), reinforcement and strengthening of grossly deteriorated/spalled columns in office buildings (Fig. 4.32), seismic strengthening of deficient columns and walls in pinball parlors (Fig. 4.33), reinforcement of slabs in buildings and parking structures (Fig. 4.34) and seismic strengthening of columns in parking lots (Fig. 4.35) and in buildings (external) (Fig. 4.36). In a number of cases, the retrofit was carried out largely as an aesthetic measure or as a preventive measure after initial cracking/exfoliation/peeling of concrete was noticed, rather than as a means of strengthening severely deteriorated or weak elements.


(a)


(b
Fig. 4.29. Seismic strengthening of internal columns of a building in Chiyoda-ku, Tokyo. Tow sheet was wrapped circumferentially; 1,100 m2 of material was used on this project.


Fig. 4.30. Seismic retrofit of edges of an internal column using Replark.


Fig. 4.31. Repair of cracked apartment floorboards with Replark.


(a) before retrofit


(b) after wrapping


(c) after finishin
Fig. 4.32. Retrofit of spalled/deteriorated columns using Replark.


(a) retrofit of columns.


(b) retrofit of wall
Fig. 4.33. Seismic retrofitting of columns and walls in a pinball parlor in Yokohama, Kanagawa Prefecture using FORCA tow sheet. A Total of 430 m2 of material was used.


(a) cracked slab prior to retrofit


(b) retrofit with ductwork in plac
Fig. 4.34. Repair of a cracked slab using Replark without shifting utilities.


Fig. 4.35. Seismic retrofit of columns in a parking lot using FORCA tow sheet.


Fig. 4.36. Seismic strengthening of external rectangular columns at an elementary school in Higashi-Kurume, Tokyo, using FORCA tow sheet.

Although a large majority of structural elements in buildings have been retrofitted using sheet type materials, a few columns have been retrofitted using a combination of tape layup and tow winding (Fig. 4.37).


(a) application of vertically oriented sheet material


(b) circumferential windin
Fig. 4.37. Shear strengthening of columns using a combination of vertically oriented Replark and circumferentially oriented tow.

Table 4.6 gives a listing of different projects in which Replark sheet type material has been used for retrofit/strengthening of components in buildings.

Table 4.6
Projects Completed Using Replark Sheet Material

Date

Location

Description

1993

Kagoshima

"MN" Newspaper Building

1993

Hokkaido

"H" University Column

1993

Hokkaido

"S" Town Housing

1994

Tokyo

"O" City Housing

1994

Hokkaido

Sezar Center Building Wall

1994

Tokyo

Power Station Floor Slab

1994

Kanagawa

Apartment House Floor Slab

1994

Hiroshima

Elementary School, Exterior Wall

1994

Hyogo

"S," Plant Column

1994

Tokyo

Parking Garage

1994

Mie

"M," Plant Column

1994

Hokkaido

"M" Condominium Beam

1994

Hokkaido

"S" Condominium Beam

1994

Fukushima

"K" High School Exterior Wall

1994

Hiroshima

"O" Town Hall, Exterior Wall

1994

Hokkaido

JR Apartment House, Wall

1994

Kanagawa

Incineration Station, Beam

1994

Osaka

"S" Plant Wall

1994

Niigata

Condominium Floor Slab

1994

Okinawa

Power Station Floor Slab

1994

Hokkaido

"B" Town Hall

1995

Niigata

Mitsubishi Electric, Plant Floor

1995

Okinawa

Power Station Floor Slab

1995

Hiroshima

"H" High School Floor Slab

1995

Iwate

"M" High School Floor Slab

1995

Hiroshima

Nippon Express Warehouse Beam

1995

Mie

"N" Hotel Floor

1995

Osaka

"M" City Incineration Station Floor Slab

1995

Kanagawa

"S" High School Wall

1995

Fukuoka

"K" Gymnasium Column & Beam

1995

Hyogo

"S" High School Column

1995

Tokyo

"H" Building Column

1995

Hyogo

Apartment House Wall

1995

Niigata

Apartment House Foundation

1995

Fukuoka

"K" Library Column

1995

Osaka

"D" High School Wall

1995

Hyogo

"K" City Hall Wall

1995

Hokkaido

"H" Town Hall Column

1995

Tochigi

Local Government Office, Beam

1995

Hyogo

"F" Electric, Exterior Wall

1995

Osaka

"F" Insurance, Building Wall

1995

Tokyo

"T" Condominium Column

1995

Kagawa

Mitsubishi Chemical Corp., Plant Beam

1995

Osaka

"N" Railway Retaining Wall

1995

Shiga

"R" Gymnasium Floor Slab

1995

Osaka

"K" Gymnasium, Opening

1995

Hyogo

"N" Building, Column

1995

Hyogo

"S" Building Exterior Wall

1995

Tokyo

"H" Hall Column

1995

Hyogo

"N" Building Column

1995

Hyogo

"S" Apartment House Exterior Wall

1995

Hiroshima

"F" Park Column

1995

Tokyo

"T" Hospital Beam

1995

Kyoto

"K" City, Incineration Station Column

1995

Tokyo

"P" Building Beam

1995

Mie

"T" Chemical, Building Wall

1995

Hokkaido

"S" Building Beam

1995

Osaka

"S" Apartment House Wall

Table 4.6 (cont.)
Projects Completed Using Replark Sheet Material

Date

Location

Description

1995

Hyogo

"M" Building Column

1995

Okayama

"M" Chemical, Building Column

1995

Hyogo

"S" Building Column

1995

Osaka

"S" Apartment House Wall

1995

Hokkaido

"R" Building Wall

1995

Tokyo

"S" Hall Column

1995

Hyogo

"C" Apartment House Column

1995

Okayama

"M" Chemical, Plant Beam

1995

Tokyo

"Z" Building Column

1995

Tokyo

"M" Condominium, Column

1995

Hiroshima

"F" National Park, Column/Beam

1995

Tokyo

"I" City Hall Beam

1995

Hokkaido

"L" Apartment House, Beam

1995

Aomori

"F" Temple Beam

1995

Okinawa

"M" Building, Beam

1995

Tokyo

"G" Building, Beam

1995

Tokyo

"S" Trade Building, Beam

1995

Ibaraki

"A" Glass, Column & Beam

1995

Hyogo

"I" City Housing, Wall

1995

Wakayama

"O" Concrete Plant, Column

1995

Oita

"K" Residence, Column

1995

Hokkaido

"H" Sugar Plant, Wall

1995

Oita

"Y" Apartment House, Column

1995

Kanagawa

"S" Railway, Tower

1995

Tottori

"T" Works, Column

1995

Yamagata

"Y" Elementary School, Beam

1995

Osaka

"D" Department Store, Column

1995

Tokyo

"E" Chemical Building, Column

1995

Kanagawa

"K" Warehouse, Floor Slab

1995

Aichi

"K" Elementary School, Wall

1995

Hokkaido

"A" Courthouse, Beam

1995

Osaka

"K" Apartment House, Floor

1995

Tokyo

"H" Apartment House, Column

1995

Tokyo

"B" Apartment House, Beam

1995

Kanagawa

"T" Housing, Beam

1995

Kanagawa

"H" Hall, Column & Beam

1995

Hyogo

"H" Horseracing Track, Pier

1995

Osaka

"K" Residence, Beam

1995

Kyoto

"M" Construction Building, Beam

1995

Hokkaido

"D" Middle School, Beam

1995

Hyogo

"R" Broadcasting Station, Beam

1995

Miyagi

"O" Elementary School

1995

Shizuoka

"M" LPG Tank, Foundation

1995

Saitama

"M" Bridge Girder

1995

Osaka

"D" Elementary School, Column & Beam

1995

Tokyo

"F" Research Center, Floor Slab

1995

Ibaraki

"O" Elementary School, Floor Slab

1995

Fukuoka

"K" Elementary School, Beam

1995

Osaka

"T" Building Expansion

1995

Yamagata

"S" Harbor, Girder

1995

Tokyo

"K" Condominium, Beam

1995

Hiroshima

"M" High School, Beam

1995

Hiroshima

"N" Elementary School, Column

1995

Gunma

"K" Branch Office, Beam

1995

Hyogo

"H" Hall Column

1995

Hokkaido

"S" Town Hall, Beam

1995

Fukushima

"F" School, Beam

1995

Hyogo

"S" City Housing, Column

1995

Tokyo

"S" Elementary School, Wall

1995

Okayama

"A" Co., Beam

1995

Tokyo

"O" Restaurant, Column & Beam

1995

Tokyo

"H" Apartment House, Beam

Table 4.6 (cont.)
Projects Completed Using Replark Sheet Material

Date

Location

Description

1995

Aomori

"K" High School, Floor

1995

Tokyo

"S" Apartment House, Floor

1995

Saitama

"T" Residence, Wall

1995

Tokyo

"O" Building, Wall

1995

Hiroshima

"M" Road, Pier

1995

Okayama

"A" Plant, Beam

1995

Hiroshima

"S" Complex, Column & Beam

1995

Tokyo

"K" Hospital, Beam

1995

Tokyo

"W" Condominium, Beam

1995

Hyogo

"O" Fire Station, Column & Beam

1995

Hokkaido

"M" High School, Floor & Beam

1995

Hokkaido

"M" School, Foundation & Wall

1995

Ibaraki

"K" Oil Quay, Girder

1995

Tokyo

"S" Condominium Basement, Column

1995

Kanagawa

"S" Elementary School

1995

Tokyo

"S" Hall Column

1995

Hyogo

"K" University, Beam

1995

Tokushima

"M" Insurance, Column & Beam

1995

Hyogo

"F" Building, Column

1995

Fukushima

"O" Oil Building, Column

1995

Nagano

"M" Middle School, Column


Note: Project locations are identified by Mitsubishi Chemical Corp. by the first character only, e.g., "K"

Table 4.7 gives a listing of building-related projects in which Torayca cloth was used.

Table 4.7
Examples of the Use of Torayca Cloth

Date

Structure

Description

Client / Geographical Location

# of Layers

Qty (m2)

8/89

NTT office

Exterior wall crack repair

NTT

  

8/90

Exterior wall

Crack repair

Volume Retailer

1

2500

11/91

School building

Exterior wall crack repair

Tottori Prefecture

1

300

3/93

Floor slab

Box girder slab reinforcement

Metropolitan Expressway

2-3

1500

5/95

Condominium

Pilotis column seismic retrofit

Real Estate Co.

 

40

4/95

Columns in classroom

Repair, seismic retrofit

School

 

20

5/95

Hospital chimney

Reinforcement

University (Taiwan)

 

100

4/95

Columns in store

Seismic retrofit

Daiei Inc.

 

100

8/95

Columns

Seismic repair and retrofit

Condo Owner (Kobe)

 

50

8/95

Underground beam

Seismic repair

Condo Owner (Osaka)

V, H, 1 each

480

10/95

Insurance co. building

Beam reinforcement

Building Owner (Aomori)

 

300

11/95

Office bldg. columns

Ind. column seismic retrofit

Building Owner (Tokyo)

H 3-4

1000

12/95

High school building

Slab reinforcement

Aomori Prefecture

 

198*

1/96

Ferry office building

Ind. column seismic retrofit

Building Owner (Chiba)

  

2/96

High school building

Ind. column seismic retrofit

Hyogo Prefecture

 

25

2/96

Office building

Ind. column seismic retrofit

Building Owner (Tokyo)

 

180

3/96

Head office building

Ind. column seismic retrofit

Building Owner (Tokyo)

 

1500

4/96

Parking tower structure

Slab & ind. column seismic retrofit

Metropolitan Expressway

 

2349*

4/96

Gym column

Ind. column seismic retrofit

Town in Ishikawa Pref.

V1, H2

710

6/96

Apartment building

Seismic retrofit

Osaka Housing Center

 

416

6/96

Apartment building

Seismic retrofit

Osaka Housing Center

 

365

6/96

Apartment building

Seismic retrofit

Osaka Housing Center

 

462

7/96

Castle

Column seismic retrofit

Osaka Prefecture

H 2-3

1500

7/96

Local govt. office bldg.

Column seismic retrofit

Ministry of Construction

H1-3

600

7/96

Office building

Column seismic retrofit

Building Owner (Tokyo)

 

230


Note: V: Vertical Alignment of Fibers, H: Horizontal Alignment of Fibers. If no direction is given, fibers are oriented horizontally/longitudinally.
* represents total work area

Table 4.8 gives examples of the use of Tonen's FORCA tow sheet.

Table 4.8
Examples of the use of FORCA Tow Sheet

Date

Description of Project

8/86

Repair of Slab, Cargo Circulation Center

6/87

Repair of Slab, Cargo Circulation Center

9/89

Tonen Kawasaki Refinery

11/90

Beam, Hospital

1/91

Tonen Kawasaki Refinery

11/91

Warehouse RC, Beam, Takaragumi

3/92

Parking lot slab

4/92

Electric Power Plant

4/92

Tonen Kawasaki Refinery

5/92

Electric Power Plant

5/92

Electric Power Plant

8/92

Electric Power Plant

9/92

Tonen Kawasaki Refinery

11/92

Warehouse Co.

1/93

Electric Power Transformer Substation

2/93

Tokyo Adachi Ward, Sanatorium

3/93

RC, Metal Co

6/93

Beam, Tokyo Ward

9/93

Fiber Co. Plant

1/93

Bank

11/93

Electric Power Plant

11/93

Slab, Apartment (Kinki Area)

2/94

Slab (2nd Step)

4/94

Physical Distribution Center

4/94

Window Frame of Bldg., Association

5/94

Plant, Film Co.

6/94

Plant, Oil Co.

7/94

Floor Beam, Kansai Electric Power

8/94

Department of Construction

8/94

Beam, Curare

9/94

Tank Base, Aomori Prefecture

9/94

Pool, High School (Tokyo)

9/94

Warehouse, Physical Distribution Center

1/94

Hotel, Wakayama Musashi

1/94

Nigata Prefecture

11/94

Floor Beam of Substation, East Japan Railway

12/94

Hotel, Chiba Prefecture Abiko City

12/94

Repair of Building

2/95

Dormitory, Takeda Drugs (Osaka)

3/95

Slab, Sendai City

3/95

Slab, Nishikawaguchi

3/95

Japan AT&T Building

3/95

Sonoda School

3/95

Basement Parking, Osaka Prefectural Office

3/95

Station, Kobe City

3/95

Junior High School, Minoo City

3/95

Sannomiya Station, Kobe City

3/95

Station, Hankyu Railway

4/95

Basement Parking, Osaka Prefectural Office

4/95

Umeda Station Parking, Hankyu Railway

5/95

Building, Dressmaking School

5/95

Slab, Okinawa Base

5/95

Repair of Central Building

5/95

Factory, Morinaga

5/95

Building

5/95

Building


Published: November 1998; WTEC Hyper-Librarian