confined masonry overview
TRANSCRIPT
![Page 1: Confined masonry overview](https://reader034.vdocuments.mx/reader034/viewer/2022051301/5a64cff67f8b9a4d0b8b49c7/html5/thumbnails/1.jpg)
1
Training on
Retrofitting Techniques and
Correction/exceptional Manual
29 May - 01 , June 2017, Kathmandu , Nepal
CONFINED MASONRY (CM)
Kuber Bogati
Structural Engineer
![Page 2: Confined masonry overview](https://reader034.vdocuments.mx/reader034/viewer/2022051301/5a64cff67f8b9a4d0b8b49c7/html5/thumbnails/2.jpg)
2
ObjectivesAs a result of this session, you should be able to:
• Understand about Confined Masonry Building : Key Concepts
• Know why Confined Masonry in Nepal
• Compare Reinforced Masonry and Confined Masonry
• Compare RC Frame with URM Infill Vs. CM,
• Know Seismic Performance of CM Buildings
• Understand How CM Resists Earthquake Effects
• Damages in Confined Masonry in Past Earthquakes
• Know General Planning and Design Aspects
• Know Guidelines for Non-engineered CM Buildings
• Introduce with Minimum Requirement & Inspection Form of CM
![Page 3: Confined masonry overview](https://reader034.vdocuments.mx/reader034/viewer/2022051301/5a64cff67f8b9a4d0b8b49c7/html5/thumbnails/3.jpg)
3
What is Confined Masonry (CM) Construction
• CM construction consists of masonry walls and horizontal and vertical RCconfining members built on all four sides of a masonry wall panel.
• Masonry walls : made either of clay brick or concrete block units
• Confining Elements :• Vertical ties : (Tie-columns or Practical columns)• Horizontal ties : (Tie-beams)
Key Components of a Confined Masonry (CM) Building
![Page 4: Confined masonry overview](https://reader034.vdocuments.mx/reader034/viewer/2022051301/5a64cff67f8b9a4d0b8b49c7/html5/thumbnails/4.jpg)
4
What is Confined Masonry (CM) Construction
• CM construction consists of masonry walls and horizontal and vertical RCconfining members built on all four sides of a masonry wall panel.
• Masonry walls : made either of clay brick or concrete block units
• Confining Elements :• Vertical ties : (Tie-columns or Practical columns)• Horizontal ties : (Tie-beams)
Key Components of a Confined Masonry (CM) Building
![Page 5: Confined masonry overview](https://reader034.vdocuments.mx/reader034/viewer/2022051301/5a64cff67f8b9a4d0b8b49c7/html5/thumbnails/5.jpg)
5
What is Confined Masonry (CM) Construction
CONFINED MASONRY
![Page 6: Confined masonry overview](https://reader034.vdocuments.mx/reader034/viewer/2022051301/5a64cff67f8b9a4d0b8b49c7/html5/thumbnails/6.jpg)
6
Confined Masonry Construction
![Page 7: Confined masonry overview](https://reader034.vdocuments.mx/reader034/viewer/2022051301/5a64cff67f8b9a4d0b8b49c7/html5/thumbnails/7.jpg)
7
What is Confined Masonry (CM) Construction
CONFINED MASONRY
![Page 8: Confined masonry overview](https://reader034.vdocuments.mx/reader034/viewer/2022051301/5a64cff67f8b9a4d0b8b49c7/html5/thumbnails/8.jpg)
8
Structural Components of a Confined Masonry (CM) Building
• Confining Elements : Provide restraint to masonry walls and protect them fromcomplete disintegration even in major EQs.
• Confining members are effective in• Enhancing the stability and integrity of masonry walls for IP & OOP EQ
Loads• Enhancing the strength (resistance) of masonry walls under EQ loads• Reducing the brittleness of masonry walls under EQ loads
• Masonry walls : Transmit the gravity load from the slab(s) above down to thefoundation. The walls act as bracing panels, which resist horizontal EQ. forces.Must be confined by concrete ties
• Floor and Roof Slabs : acts as diaphragms, transmit gravity and lateral loads tothe walls
• Plinth Band : Transmits the load from the walls down to the foundation.
• Foundation : Transmits the loads from the structure to the soils
![Page 9: Confined masonry overview](https://reader034.vdocuments.mx/reader034/viewer/2022051301/5a64cff67f8b9a4d0b8b49c7/html5/thumbnails/9.jpg)
9
Construction Masonry (CM) – Global Context
• Evolved through informal process based on performance in earthquake• Practiced in central and south American countries since as early as 1930’s and
40’s• Currently practiced in several countries of high seismic risks- Latin, America,
Mediterranean Europe, Iran, Indonesia, China and in India (late comer)• CM if Properly built, shows satisfactory performance in severe earthquakes in
the past
• 1985 Mexico earthquake (M8.0)• 2001 La paz earthquake (elsalvador) (M7.7)• 2004 Sumtra earthquake (Indonesia) (M9.0)• 2007 Pisco earthquake (Peru) (M8.0)• 2010 Chile earthquake (M8.8) and others
• Confined masonry network established in 2008 under WHE with two objectives• To improve design and construction of CM where is currently in use• To introduce CM in areas where it can reduce seismic risks
![Page 10: Confined masonry overview](https://reader034.vdocuments.mx/reader034/viewer/2022051301/5a64cff67f8b9a4d0b8b49c7/html5/thumbnails/10.jpg)
10
World Wide Practices
1. Chile2. Colombia3. Mexico4. Peru5. Argentina6. Eurocode7. Algeria8. China9. Iran10.Indonesia11.India
![Page 11: Confined masonry overview](https://reader034.vdocuments.mx/reader034/viewer/2022051301/5a64cff67f8b9a4d0b8b49c7/html5/thumbnails/11.jpg)
11
Confined Masonry in Nepal - Context
• Construction of reinforced concrete frame and masonry wall is trending in citiesand towns
• Heavy damage observed in those construction in the last earthquake even in lowPGA and spectral acceleration
• Non-ductile RC frame construction• Unreinforced masonry walls vulnerable to lateral loading
• The presence of wall is in RC construction is not utilized as well as theconsequence of irregularity is overlooked
Confined masonry construction provides opportunity for improved performance in earthquake utilizing constriction from both RC and masonry components [technologies which require similar (preferably lower) level of construction skills and are economically viable]
Its simple in design and analogues to conventional construction of RC frame with walls (EXTENSIVE ENGINEERING INPUT NOT REQUIRED)
![Page 12: Confined masonry overview](https://reader034.vdocuments.mx/reader034/viewer/2022051301/5a64cff67f8b9a4d0b8b49c7/html5/thumbnails/12.jpg)
Reinforced Masonry vs. Confined Masonry
• Reinf. Enhance strength, Stability
• Corners, T-junction, additional Location
![Page 13: Confined masonry overview](https://reader034.vdocuments.mx/reader034/viewer/2022051301/5a64cff67f8b9a4d0b8b49c7/html5/thumbnails/13.jpg)
13
Reinforced Concrete Frame Construction
![Page 14: Confined masonry overview](https://reader034.vdocuments.mx/reader034/viewer/2022051301/5a64cff67f8b9a4d0b8b49c7/html5/thumbnails/14.jpg)
14
RC frame with URM infill vs. Confined Masonry
![Page 15: Confined masonry overview](https://reader034.vdocuments.mx/reader034/viewer/2022051301/5a64cff67f8b9a4d0b8b49c7/html5/thumbnails/15.jpg)
15
RC frame with URM infill vs. Confined Masonry
Integrity of wall and frame
Construction sequence
Frame first, Wall later Wall first, Column/Beams later
Source : Tom Schacher
![Page 16: Confined masonry overview](https://reader034.vdocuments.mx/reader034/viewer/2022051301/5a64cff67f8b9a4d0b8b49c7/html5/thumbnails/16.jpg)
17
Seismic Performance of CM
Confined masonry construction is found in countries/regions with very high seismic risk,
• Latin America (Mexico, Chile, Peru, Argentina),
• Mediterranean Europe (Italy, Slovenia),
• South Asia (Indonesia), and the Far East (China).
• In some countries (e.g. Italy) for almost 100 years
• If properly built, shows satisfactory seismic performance
EXTENSIVE ENGINEERING INPUT NOT REQUIRED!
![Page 17: Confined masonry overview](https://reader034.vdocuments.mx/reader034/viewer/2022051301/5a64cff67f8b9a4d0b8b49c7/html5/thumbnails/17.jpg)
18
Seismic Performance of CM
Oaxaca quake,September 1999
Tecomán earthquake,January 2003
![Page 18: Confined masonry overview](https://reader034.vdocuments.mx/reader034/viewer/2022051301/5a64cff67f8b9a4d0b8b49c7/html5/thumbnails/18.jpg)
19
Seismic Performance of CM
Confined masonry construction has been exposed to several destructive earthquakes:
• 1985 Lloleo, Chile (magnitude 7.8)
• 1985 Mexico City, Mexico (magnitude 8.0)
• 2001 El Salvador (magnitude 7.7)
• 2003 Tecoman, Mexico (magnitude 7.6)
• 2007 Pisco, Peru (magnitude 8.0)
• 2003 Bam, Iran (magnitude 6.6)
• 2004 The Great Sumatra Earthquake and Tsunami, Indonesia (magnitude 9.0)
• 2007 Pisco, Peru (magnitude 8.0)
• 2010 Maule, Chile earthquake (magnitude 8.8)
• 2010 Haiti earthquake (magnitude 7.0)
Confined masonry buildings performed very well in these majorearthquakes – some buildings were damaged, but no humanlosses
![Page 19: Confined masonry overview](https://reader034.vdocuments.mx/reader034/viewer/2022051301/5a64cff67f8b9a4d0b8b49c7/html5/thumbnails/19.jpg)
20
Seismic Performance of CM
A six-storey confined masonry building remained undamaged in the August 2007 Pisco, Peru earthquake (Magnitude 8.0) while many other masonry buildings experienced severe damage or collapse
Confined Masonry Performed Very Well in Past Earthquakes
![Page 20: Confined masonry overview](https://reader034.vdocuments.mx/reader034/viewer/2022051301/5a64cff67f8b9a4d0b8b49c7/html5/thumbnails/20.jpg)
21
How Confined Masonry Buildings Resist Earthquake Effects
![Page 21: Confined masonry overview](https://reader034.vdocuments.mx/reader034/viewer/2022051301/5a64cff67f8b9a4d0b8b49c7/html5/thumbnails/21.jpg)
22
How Confined Masonry Buildings Resist Earthquake Effects
Toothing : Monolithic action Horizontal Reinforcement
![Page 22: Confined masonry overview](https://reader034.vdocuments.mx/reader034/viewer/2022051301/5a64cff67f8b9a4d0b8b49c7/html5/thumbnails/22.jpg)
23
How Confined Masonry Buildings Resist Earthquake Effects
Mechanism of shear resistance for a confined masonry wall panel
![Page 23: Confined masonry overview](https://reader034.vdocuments.mx/reader034/viewer/2022051301/5a64cff67f8b9a4d0b8b49c7/html5/thumbnails/23.jpg)
24
How Confined Masonry Buildings Resist Earthquake Effects
Confined Masonry Building : Vertical Truss Model (left) and Collapse at theGround Floor Level (right)
Masonry : Diagonal Struts RC : Tension/compression Cracking at G.F. (soft story) : horizontal reinforcement
![Page 24: Confined masonry overview](https://reader034.vdocuments.mx/reader034/viewer/2022051301/5a64cff67f8b9a4d0b8b49c7/html5/thumbnails/24.jpg)
25
How Confined Masonry Buildings Resist Earthquake Effects
Figure 8. Critical regions in a confined masonry building: a) a general diagram showing critical regions in the RC tie-columns
Masonry : Diagonal Struts RC : Tension/compression Cracking at G.F. (soft story) : horizontal reinforcement
![Page 25: Confined masonry overview](https://reader034.vdocuments.mx/reader034/viewer/2022051301/5a64cff67f8b9a4d0b8b49c7/html5/thumbnails/25.jpg)
27
How Confined Masonry Buildings Resist Earthquake Effects…
Failure modes characteristic of CM Walls :
• Shear Failure Mode (due to IP Seismic Loads)
• Flexural Failure Mode (due to OOP Loads)
![Page 26: Confined masonry overview](https://reader034.vdocuments.mx/reader034/viewer/2022051301/5a64cff67f8b9a4d0b8b49c7/html5/thumbnails/26.jpg)
29
How Confined Masonry Buildings Resist Earthquake Effects…
Shear Failure Mode (due to IP Seismic Loads)
Flexural Failure Mode (due to OOP Loads)
![Page 27: Confined masonry overview](https://reader034.vdocuments.mx/reader034/viewer/2022051301/5a64cff67f8b9a4d0b8b49c7/html5/thumbnails/27.jpg)
30
Key Factors Influencing Seismic Resistance of CM Structures
• Wall Density : Strength
• Masonry Units and Mortar : (Stronger)
• Tie -Columns : (Ductility & Stability)
• Horizontal Wall Reinforcement
• Openings : 10% , Load path,
![Page 28: Confined masonry overview](https://reader034.vdocuments.mx/reader034/viewer/2022051301/5a64cff67f8b9a4d0b8b49c7/html5/thumbnails/28.jpg)
33
Key Factors Influencing Seismic Resistance of CM Structures…
Horizontal Wall Reinforcement
Failure modes in the confined masonry walls with openings
The walls with largeropenings develop diagonalcracks
![Page 29: Confined masonry overview](https://reader034.vdocuments.mx/reader034/viewer/2022051301/5a64cff67f8b9a4d0b8b49c7/html5/thumbnails/29.jpg)
34
Damages in Confined Masonry in Past Earthquakes
![Page 30: Confined masonry overview](https://reader034.vdocuments.mx/reader034/viewer/2022051301/5a64cff67f8b9a4d0b8b49c7/html5/thumbnails/30.jpg)
35
Damage Observation: Topics
1.Masonry damage (in-and out-of-plane)
2.RC tie-columns
3.Tie-beam-to-tie-column joints
4.Confining elements around openings
![Page 31: Confined masonry overview](https://reader034.vdocuments.mx/reader034/viewer/2022051301/5a64cff67f8b9a4d0b8b49c7/html5/thumbnails/31.jpg)
36
In-plane shear failure of masonry walls at the base level - hollow clay blocks (Cauquenes)
![Page 32: Confined masonry overview](https://reader034.vdocuments.mx/reader034/viewer/2022051301/5a64cff67f8b9a4d0b8b49c7/html5/thumbnails/32.jpg)
37
In-plane shear failure of masonry walls at the base level - hollow clay blocks (Cauquenes)
![Page 33: Confined masonry overview](https://reader034.vdocuments.mx/reader034/viewer/2022051301/5a64cff67f8b9a4d0b8b49c7/html5/thumbnails/33.jpg)
38
Out-of-Plane Wall Damage
Damage at the 2nd floor level
• An example of out-of-plane damage observed in a three-storey building
• The damage concentrated at the upper floor levels
• The building had concrete floors and timber truss roof
• The same building suffered severe in-plane damage
![Page 34: Confined masonry overview](https://reader034.vdocuments.mx/reader034/viewer/2022051301/5a64cff67f8b9a4d0b8b49c7/html5/thumbnails/34.jpg)
39
Tie-Column Failure
![Page 35: Confined masonry overview](https://reader034.vdocuments.mx/reader034/viewer/2022051301/5a64cff67f8b9a4d0b8b49c7/html5/thumbnails/35.jpg)
40
Buckling of a Tie-Column due to the Toe Crushing
![Page 36: Confined masonry overview](https://reader034.vdocuments.mx/reader034/viewer/2022051301/5a64cff67f8b9a4d0b8b49c7/html5/thumbnails/36.jpg)
41
Shear Failure of RC Tie-Columns
![Page 37: Confined masonry overview](https://reader034.vdocuments.mx/reader034/viewer/2022051301/5a64cff67f8b9a4d0b8b49c7/html5/thumbnails/37.jpg)
42
Inadequate Anchorage of Tie-Beam Reinforcement
![Page 38: Confined masonry overview](https://reader034.vdocuments.mx/reader034/viewer/2022051301/5a64cff67f8b9a4d0b8b49c7/html5/thumbnails/38.jpg)
43
Deficiencies in Tie-Beam – to - Tie – Column Joint Reinforcement Detailing
![Page 39: Confined masonry overview](https://reader034.vdocuments.mx/reader034/viewer/2022051301/5a64cff67f8b9a4d0b8b49c7/html5/thumbnails/39.jpg)
44
Absence of Confining Elements at the Openings
![Page 40: Confined masonry overview](https://reader034.vdocuments.mx/reader034/viewer/2022051301/5a64cff67f8b9a4d0b8b49c7/html5/thumbnails/40.jpg)
45
In-Plane Shear Cracking – the Effect of Confinement
Unconfined openings Confined openings
![Page 41: Confined masonry overview](https://reader034.vdocuments.mx/reader034/viewer/2022051301/5a64cff67f8b9a4d0b8b49c7/html5/thumbnails/41.jpg)
46
Key Causes of Damage in CM
1.Inadequate wall density
2.Poor quality of masonry materials and construction
3.Inadequate detailing of reinforcement in confining elements
4.Absence of confining elements at openings
5.Geotechnical issues
![Page 42: Confined masonry overview](https://reader034.vdocuments.mx/reader034/viewer/2022051301/5a64cff67f8b9a4d0b8b49c7/html5/thumbnails/42.jpg)
47
General Planning and Design Aspects
• Architectural Guideline
• Construction Guideline
![Page 43: Confined masonry overview](https://reader034.vdocuments.mx/reader034/viewer/2022051301/5a64cff67f8b9a4d0b8b49c7/html5/thumbnails/43.jpg)
48
Architectural Guideline
1. Plan Shape : Rectangular
NOYES
IRREGULARSYMMENTRICAL
![Page 44: Confined masonry overview](https://reader034.vdocuments.mx/reader034/viewer/2022051301/5a64cff67f8b9a4d0b8b49c7/html5/thumbnails/44.jpg)
49
Architectural Guideline
2. Plan Shape : Length-to-width ratio less than 4 times
NOYES
POORLY PROPORTIONED PLAN WELL PROPORTIONED PLAN
![Page 45: Confined masonry overview](https://reader034.vdocuments.mx/reader034/viewer/2022051301/5a64cff67f8b9a4d0b8b49c7/html5/thumbnails/45.jpg)
50
Architectural Guideline
3. Walls should be in a symmetrical
NO YES
INADEQUATE PLAN : LAYOUT ADEQUATE SHAPE
![Page 46: Confined masonry overview](https://reader034.vdocuments.mx/reader034/viewer/2022051301/5a64cff67f8b9a4d0b8b49c7/html5/thumbnails/46.jpg)
51
Architectural Guideline
4. Walls should be continuous up the building height
NO YES
LOAD PATH NOT CLEAR LOAD PATH CLEAR
![Page 47: Confined masonry overview](https://reader034.vdocuments.mx/reader034/viewer/2022051301/5a64cff67f8b9a4d0b8b49c7/html5/thumbnails/47.jpg)
52
Architectural Guideline
5. Opening : same position up the building height#Vertical ties : At both sides ( if opening <1.5 Sq.m.) (Toproduce diagonal Strut Action)
NO YES
POOR LOCATION OF WINDOW AND DOOR OPENING
GOOD LOCATION OF WINDOW AND DOOR OPENING
![Page 48: Confined masonry overview](https://reader034.vdocuments.mx/reader034/viewer/2022051301/5a64cff67f8b9a4d0b8b49c7/html5/thumbnails/48.jpg)
53
Architectural Guideline
6. Confining Elements : Tie-beams at 3m vertical spacing: Tie-columns at 4m: Wall to wall intersection: Free end of a wall
![Page 49: Confined masonry overview](https://reader034.vdocuments.mx/reader034/viewer/2022051301/5a64cff67f8b9a4d0b8b49c7/html5/thumbnails/49.jpg)
54
Architectural Guideline
7. Walls : At least three fully confined walls should beprovided in each direction
Inadequate Wall Distribution Adequate Wall Distribution
NOYES
![Page 50: Confined masonry overview](https://reader034.vdocuments.mx/reader034/viewer/2022051301/5a64cff67f8b9a4d0b8b49c7/html5/thumbnails/50.jpg)
55
Architectural Guideline
8. Walls Density : At least 5 % in each of two orthogonaldirection
𝑾𝒂𝒍𝒍 𝑫𝒆𝒏𝒔𝒊𝒕𝒚 =𝑻𝒐𝒕𝒂𝒍 𝑿 − 𝒔𝒆𝒄𝒕𝒊𝒐𝒏𝒂𝒍 𝑨𝒓𝒆𝒂 𝒐𝒇 𝒂𝒍𝒍 𝒘𝒂𝒍𝒍𝒔 𝒊𝒏 𝒐𝒏𝒆 𝒅𝒊𝒓𝒆𝒄𝒕𝒊𝒐𝒏
𝑺𝒖𝒎 𝒐𝒇 𝑭𝒍𝒐𝒐𝒓 𝒑𝒍𝒂𝒏 𝒂𝒓𝒆𝒂 𝒇𝒐𝒓 𝒂𝒍𝒍 𝒇𝒍𝒐𝒐𝒓𝒔 𝒊𝒏 𝒂 𝒃𝒖𝒊𝒍𝒅𝒊𝒏𝒈
Eurocode 8 (1996)a) At least 2% for a site with a design ground accln up to
0.2g (corresponding to seismic zone II of Indiab) At least 4% for a site with a design ground accln up to
0.3g (corresponding to seismic zone III of Indiac) At least 5% for a site with a design ground accln up to
0.4g (corresponding to seismic zone IV of India
![Page 51: Confined masonry overview](https://reader034.vdocuments.mx/reader034/viewer/2022051301/5a64cff67f8b9a4d0b8b49c7/html5/thumbnails/51.jpg)
56
Architectural Guideline
9. Building Height : Low-to medium-rise (Eurocode 8,1996)
Eurocode 8 (1996)a) Up to 4-story high for a site with a design ground
accln up to 0.2g (corresponding to seismic zone II of India
b) Up to 3-story high for a site with a design ground accln up to 0.3g (corresponding to seismic zone III of India
c) Up to 2-story high for a site with a design ground accln up to 0.4g (corresponding to seismic zone IV of India
![Page 52: Confined masonry overview](https://reader034.vdocuments.mx/reader034/viewer/2022051301/5a64cff67f8b9a4d0b8b49c7/html5/thumbnails/52.jpg)
57
Guidelines for Non-Engineered CM Buildings
𝑺𝒕𝒐𝒓𝒆𝒚 ∶ 𝑶𝒏𝒆 𝒐𝒓 𝑻𝒘𝒐
![Page 53: Confined masonry overview](https://reader034.vdocuments.mx/reader034/viewer/2022051301/5a64cff67f8b9a4d0b8b49c7/html5/thumbnails/53.jpg)
58
Guidelines for Non-Engineered CM Buildings
𝟏.𝑾𝒂𝒍𝒍 𝑫𝒆𝒏𝒔𝒊𝒕𝒚𝒂.𝑴𝒂𝒔𝒐𝒏𝒓𝒚𝑾𝒂𝒍𝒍𝒔
Walls Density : At least 5 % in each of two orthogonal direction
![Page 54: Confined masonry overview](https://reader034.vdocuments.mx/reader034/viewer/2022051301/5a64cff67f8b9a4d0b8b49c7/html5/thumbnails/54.jpg)
59
Guidelines for Non-Engineered CM Buildings2. Openings𝒂.𝑴𝒂𝒔𝒐𝒏𝒓𝒚𝑾𝒂𝒍𝒍𝒔
![Page 55: Confined masonry overview](https://reader034.vdocuments.mx/reader034/viewer/2022051301/5a64cff67f8b9a4d0b8b49c7/html5/thumbnails/55.jpg)
60
Guidelines for Non-Engineered CM Buildings
3. Wall Spacing𝒂.𝑴𝒂𝒔𝒐𝒏𝒓𝒚𝑾𝒂𝒍𝒍𝒔
• Building with Flexible floor should not exceed4.0 m in high seismic region
![Page 56: Confined masonry overview](https://reader034.vdocuments.mx/reader034/viewer/2022051301/5a64cff67f8b9a4d0b8b49c7/html5/thumbnails/56.jpg)
61
Guidelines for Non-Engineered CM Buildings
4. Wall Dimensions and H/t ratios Restrictions
𝒂.𝑴𝒂𝒔𝒐𝒏𝒓𝒚𝑾𝒂𝒍𝒍𝒔
• Minimum wall thickness 110 mm
• H/t : less than 25, for one or two storey
• H/L : Should not less be than 0.5
• Maximum wall height : 3 m
![Page 57: Confined masonry overview](https://reader034.vdocuments.mx/reader034/viewer/2022051301/5a64cff67f8b9a4d0b8b49c7/html5/thumbnails/57.jpg)
62
Guidelines for Non-Engineered CM Buildings
5. Parapets and Gable Walls𝒂.𝑴𝒂𝒔𝒐𝒏𝒓𝒚𝑾𝒂𝒍𝒍𝒔
• Parapets
• RC tie column should extent to the top : (1.2m)
• Otherwise Parapet height : 0.5m
![Page 58: Confined masonry overview](https://reader034.vdocuments.mx/reader034/viewer/2022051301/5a64cff67f8b9a4d0b8b49c7/html5/thumbnails/58.jpg)
63
Guidelines for Non-Engineered CM Buildings6. Toothing at the Wall – to – tie-column interface
Toothing in confined masonry walls: a) machine-made hollow units, b) hand-made solidunits, and c) provision of horizontal reinforcement when toothing is not possible.
![Page 59: Confined masonry overview](https://reader034.vdocuments.mx/reader034/viewer/2022051301/5a64cff67f8b9a4d0b8b49c7/html5/thumbnails/59.jpg)
64
Guidelines for Non-Engineered CM Buildings6. Toothing at the Wall – to – tie-column interface
Toothing applications: a) recommended construction practice (S. Brzev), and b) not recommended - absence of toothing in concrete block construction (C. Meisl).
![Page 60: Confined masonry overview](https://reader034.vdocuments.mx/reader034/viewer/2022051301/5a64cff67f8b9a4d0b8b49c7/html5/thumbnails/60.jpg)
65
Guidelines for Non-Engineered CM Buildings
𝟏. 𝑺𝒑𝒂𝒄𝒊𝒏𝒈
𝒃. Confining Elements (Tie-Columns and Tie-Beams)
![Page 61: Confined masonry overview](https://reader034.vdocuments.mx/reader034/viewer/2022051301/5a64cff67f8b9a4d0b8b49c7/html5/thumbnails/61.jpg)
66
Guidelines for Non-Engineered CM Buildings
𝟏. 𝑺𝒑𝒂𝒄𝒊𝒏𝒈
𝒃. Confining Elements (Tie-Columns and Tie-Beams)
![Page 62: Confined masonry overview](https://reader034.vdocuments.mx/reader034/viewer/2022051301/5a64cff67f8b9a4d0b8b49c7/html5/thumbnails/62.jpg)
67
Guidelines for Non-Engineered CM Buildings
2. Minimum Dimensions
𝒃. Confining Elements (Tie-Columns and Tie-Beams)
• Tie – column size : (Depth x Width) : 150 mm x t
• Tie-beam Size : same as tie-column size or tx150 mm
![Page 63: Confined masonry overview](https://reader034.vdocuments.mx/reader034/viewer/2022051301/5a64cff67f8b9a4d0b8b49c7/html5/thumbnails/63.jpg)
68
Guidelines for Non-Engineered CM Buildings
3. Reinforcements
𝒃. Confining Elements (Tie-Columns and Tie-Beams)
• Minimum 4 reinforcing bars for tie - column , 2 tie - beam
• Bar size : 12 mm dia (Fe 500 or Fe 415)
• Stirrups/C-hooks : 6 mm dia @150 mm at center
![Page 64: Confined masonry overview](https://reader034.vdocuments.mx/reader034/viewer/2022051301/5a64cff67f8b9a4d0b8b49c7/html5/thumbnails/64.jpg)
69
It is preferred to place beam reinforcement outside the column reinforcement cage
YESNO
![Page 65: Confined masonry overview](https://reader034.vdocuments.mx/reader034/viewer/2022051301/5a64cff67f8b9a4d0b8b49c7/html5/thumbnails/65.jpg)
70
Guidelines for Non-Engineered CM Buildings
3. Reinforcements
𝒃. Confining Elements (Tie-Columns and Tie-Beams)
![Page 66: Confined masonry overview](https://reader034.vdocuments.mx/reader034/viewer/2022051301/5a64cff67f8b9a4d0b8b49c7/html5/thumbnails/66.jpg)
71
Guidelines for Non-Engineered CM Buildings
3. Reinforcements
𝒃. Confining Elements (Tie-Columns and Tie-Beams)
![Page 67: Confined masonry overview](https://reader034.vdocuments.mx/reader034/viewer/2022051301/5a64cff67f8b9a4d0b8b49c7/html5/thumbnails/67.jpg)
72
Guidelines for Non-Engineered CM Buildings
4. Construction issues
𝒃. Confining Elements (Tie-Columns and Tie-Beams)
• Confining elements must be carefully constructed
• Slump : 125 mm recommended
• Concrete can be cast in three lifts when continuous is not possible
• RC tie-columns should not be cast above the completed portion of the wall
![Page 68: Confined masonry overview](https://reader034.vdocuments.mx/reader034/viewer/2022051301/5a64cff67f8b9a4d0b8b49c7/html5/thumbnails/68.jpg)
73
Guidelines for Non-Engineered CM Buildings5. Foundation and Plinth Construction• Similar as traditional masonry construction
![Page 69: Confined masonry overview](https://reader034.vdocuments.mx/reader034/viewer/2022051301/5a64cff67f8b9a4d0b8b49c7/html5/thumbnails/69.jpg)
74
Guidelines for Non-Engineered CM Buildings5. Foundation and Plinth Construction• Similar as traditional masonry construction
![Page 70: Confined masonry overview](https://reader034.vdocuments.mx/reader034/viewer/2022051301/5a64cff67f8b9a4d0b8b49c7/html5/thumbnails/70.jpg)
75
Guidelines for Non-Engineered CM Buildings
𝒄. Additional Requirements for Building with Flexible Diaphragms
![Page 71: Confined masonry overview](https://reader034.vdocuments.mx/reader034/viewer/2022051301/5a64cff67f8b9a4d0b8b49c7/html5/thumbnails/71.jpg)
76
Guidelines for Non-Engineered CM Buildings
𝒅. 𝑪𝒐𝒏𝒔𝒕𝒓𝒖𝒄𝒕𝒊𝒐𝒏 𝑸𝒖𝒂𝒍𝒊𝒕𝒚
• Construction quality has a significant bearing in seismic performance of CM building
• Properly designed and built CM buildings performed well in past earthquakes in most cases
• Poorly built ones experienced damage
![Page 72: Confined masonry overview](https://reader034.vdocuments.mx/reader034/viewer/2022051301/5a64cff67f8b9a4d0b8b49c7/html5/thumbnails/72.jpg)
77
An Example Illustrating Wall Density Calculation
![Page 73: Confined masonry overview](https://reader034.vdocuments.mx/reader034/viewer/2022051301/5a64cff67f8b9a4d0b8b49c7/html5/thumbnails/73.jpg)
78
An Example Illustrating Wall Density Calculation
Storey : twoSeismic Zone : VWall thickness : 110 mm
Typical Floor Plan of a Confined Masonry Building
![Page 74: Confined masonry overview](https://reader034.vdocuments.mx/reader034/viewer/2022051301/5a64cff67f8b9a4d0b8b49c7/html5/thumbnails/74.jpg)
79
An Example Illustrating Wall Density Calculation
1. Floor area per floor = 4*9.2 = 36.8 m^2Total floor area for 2 floorsTOTAL FLOOR AREA = 2*36.8 = 73.6 m^2
2. Wall density in the longitudinal directionWall area ( walls 1 & 2 only) :
Wall Area = [9.2+(9.2-1.2)]*(0.11) = 1.9 m^2
𝑾𝒂𝒍𝒍 𝑫𝒆𝒏𝒔𝒊𝒕𝒚 =𝑾𝒂𝒍𝒍 𝑨𝒓𝒆𝒂
𝑻𝒐𝒕𝒂𝒍 𝑭𝒍𝒐𝒐𝒓 𝑨𝒓𝒆𝒂
=𝟏. 𝟗
𝟕𝟑. 𝟔= 𝟎. 𝟎𝟐𝟔 = 2.6 %
![Page 75: Confined masonry overview](https://reader034.vdocuments.mx/reader034/viewer/2022051301/5a64cff67f8b9a4d0b8b49c7/html5/thumbnails/75.jpg)
80
An Example Illustrating Wall Density Calculation
3. Wall density in the Transverse directionWall area ( walls A, B & C) :
Wall Area=[4.0+(4.0-1.2)+4.0-1.2]*(0.11) = 1.1 m^2
𝑾𝒂𝒍𝒍 𝑫𝒆𝒏𝒔𝒊𝒕𝒚 =𝑾𝒂𝒍𝒍 𝑨𝒓𝒆𝒂
𝑻𝒐𝒕𝒂𝒍 𝑭𝒍𝒐𝒐𝒓 𝑨𝒓𝒆𝒂=
𝟏. 𝟏
𝟕𝟑. 𝟔= 𝟎. 𝟎𝟏𝟓 = 1.50 %
![Page 76: Confined masonry overview](https://reader034.vdocuments.mx/reader034/viewer/2022051301/5a64cff67f8b9a4d0b8b49c7/html5/thumbnails/76.jpg)
81
THANK YOU