EARTHQUAKE SAFE CONSTRUCTION OF MASONRY BUILDINGS Simplified Guideline for All New Buildings in the Seismic Zone III of India

Transcription

1 EARTHQUAKE SAFE CONSTRUCTION OF MASONRY BUILDINGS Simplified Guideline for All New Buildings in the Seismic Zone III of India Zone III Introduction: As usual new construction of uildings under IAY, Prime Minister Rojgar Yojana and uildings under various other National and State schemes get started in the month of May. The Ministry of Home Affairs is keen that All New Buildings should e made earthquake resistant in the first instant so that we do not add to the stock of existing unsafe uildings. Since most of the uildings are constructed using rickwork or, solid hollow concrete locks with flat roofs, very simple illustrated guidance is provided in the attached rochure for incorporating the earthquake resistant features suitale for seismic zone III. Essential Elements for Earthquake Safety : The essential elements required to make a uilding earthquake safe are as given in Figure. Some additional requirements are detailed in the following paragraphs. 6. Lintel Band. Roof/ Floor Band. Vertical reinforcing ar at corner 4. Door 5. Window 6. Plinth Band. GOOD CEMENT MORTAR: The cement mortar should e used in the ratio of part of cement with 6 parts of sand ( sack of cement mixed with 6 equal sacks of sand).. HORIZONTAL SEISMIC BANDS: Figure : Essential Internal Elements in Buildings for Earthquake Safety A seismic and consists of reinforced concrete flat runner through all external and internal masonry walls at the following levels in the uilding. a. at the plinth level of the uilding. at the levels of lintels of doors and windows c. at the ceiling level of roofs consisting of wooden joists or, prefaricated reinforced concrete eams or, planks. (Such and will not e necessary if the roof consists of Reinforced Concrete or, Reinforced Brick slas cast on the walls covering a minimum of / of the thickness of the wall.) The dimensions of the and and the reinforcement inside depend upon the length of the walls etween the perpendicular cross walls. The tale elow (Tale-) shows the dimensions to e adopted for the seismic ands and the internal reinforcement details to e provided. The reinforcement and ending details of seismic ands are given in the Figure-. Reinforcing ars will e of Fe 45 type [TOR or, High Yield Strength Deformed, i.e. HYSD ars] 5 4 The details given here are extracted from IS: Code of Practice as applicale to uildings with Brick/ Concrete lock walls and R.C. flat sla roofs. Details not given here may e seen in the Code.

2 @50 6@50 (a) () (c) (d) (e) (a) Section of the Band with longitudinal steel ars () Section of the Band with 4 longitudinal steel ars (c) Structural Plan at L- type wall junction (d) Structural Plan at T- type wall junction (e) Dimensional view of the L - type wall junction (f) Dimensional view of the T - type wall junction Figure-: Reinforcement and Bending Details of Seismic Bands (f). Longitudinal reinforcements. Lateral Ties. Vertical reinforcement at corners,, Wall thickness Tale-: Recommended size and longitudinal steel in Seismic Bands (Zone III) Internal length of Residential uildings Important Pulic Buildings (Schools, Hospitals, Meeting Halls, Anganwadis, etc.) wall Size of the and No. of Bars Dia (mm) Size of the and No. of Bars Dia (mm) 5 m or, less 0 cm x wall width 8 0 cm x wall width 8 6 m 0 cm x wall width 8 0 cm x wall width 0 7 m 5 cm x wall width 0 5 cm x wall width 8 m 5 cm x wall width 5 cm x wall width 4 0. VERTICAL REINFORCEMENT IN THE BRICK WALLS: For earthquake safety in seismic zone III reinforcing ars have to e emedded in rick masonry at the corners of all the rooms and the side of the door openings. Window openings larger than 60 cm in width will also need such reinforcing ars (Figure 4). The diameter of the ar depends upon the numer of storeys in the uilding. The recommendations are given in Tale-. Providing the vertical ars in the rickwork and concrete locks requires special techniques which could e easily learnt y the supervising engineers and masons will need to e trained.

3 These vertical ars have to e started from the foundation concrete, will pass through all seismic ands where they will e tied to the and reinforcements using inding wire and emedded to the ceiling and/roof sla as the case may e using a 00 mm 90 end. Sometimes the vertical ars will not e made in one full length. In that case the extension of the vertical reinforcement ars are required, an overlap of minimum of 50 times the ar diameter should e provided. The two overlapped reinforcement ars should e tied together y using the inding wires. Tale-: Recommended size of vertical steel in Seismic Bands (Zone III) No. of storeys Floor Residential uildings * Important Pulic Buildings * (Schools, Hospitals, Meeting Halls, Anganwadis, etc.) Dia of Single HYSD(TOR) Bar at corners of room (mm) Dia of Single HYSD (TOR) Bar at corners of room (mm) One Two Top - 0 Bottom - Three Four Top 0 0 Middle Bottom Top 0 0 Third 0 Second 6 Bottom 0 /4 /4 /4 (a) () a & : Alternate courses in one rick wall : One rick length ½ : Half rick length ¼ : Quarter of a rick length ¾ : Three quarters of a rick length : Vertical reinforcement ars with Concrete/ mortar filling in pocket of M0 grade (:½: nominal mix) Figure-: Typical Details of Providing Vertical Steel Bars in Brick Masonry Tale-: Recommended joint details with the vertical reinforcement at corner for masonry walls using different kind of materials Type of Joint Corner reinforcement in case of Brick Masonry Corner reinforcement in case of Solid Concrete Block Masonry /4 /4 /4 Corner reinforcement in case of Hollow Concrete Block Masonry (see the hole and slit made) L- Joint T- Joint

4 4. VERTICAL REINFORCEMENT AT JAMBS OF OPENINGS: All door and window openings wider than 600 mm will have vertical reinforcement in jams as shown in Figure-4 where required as per Tale-. (a) Sectional Elevation of Door () Sectional Elevation of Window (c) Section - Figure-4: Typical Details of Providing Vertical Steel Bars around doors/windows 5. FOUNDATION Foundation width 'B' should e decided y the load coming on the foundation and the earing capacity. Masonry width may e reduced y ½ times T in every step of 50 mm height. NOTE: In sandy soils with high water tale within 5 m depth elow ground level, which may get liquefied during earthquake of MSK intensity VII, pile foundation need to e used in consultation with the Structural/ Geotechnical Engineer. Masonry in C.M.:6 Masonry in C.M.:6 Well compacted Sand P.C.C :4:8 Floor Finish Plinth Band Plinth Level < 5 T.5 T T 6mm c/c 00 TOR Ground Level T - 0 for Brick Work 00 for Block Work < Figure-5: Foundation Detail with Plinth Band in Brick or, Concrete Block Masonry WELL COMPACTED SOIL B Prepared y: Professor Anand S. Arya and Jnananjan Panda Tel: ; anand.s.arya@undp.org, jnananjan.panda@undp.org National Disaster Management Division, Ministry of Home Affairs, North Block, New Delhi, India Tel: ; Tel/Fax: ; Fax: ; ndmindia@nic.in; dsdm@nic.in; Wesite: Prepared under the GoI UNDP Disaster Risk Management Programme

5 EARTHQUAKE SAFE CONSTRUCTION OF MASONRY BUILDINGS Simplified Guideline for All New Buildings in the Seismic Zone IV of India Zone IV Introduction: As usual new construction of uildings under IAY, Prime Minister Rojgar Yojana and uildings under various other National and State schemes get started in the month of May. The Ministry of Home Affairs is keen that All New Buildings should e made earthquake resistant in the first instant so that we do not add to the stock of existing unsafe uildings. Since most of the uildings are constructed using rickwork or, solid hollow concrete locks with flat roofs, very simple illustrated guidance is provided in the attached rochure for incorporating the earthquake resistant features suitale for seismic zone IV. Essential Elements for Earthquake Safety : The essential elements required to make a uilding earthquake safe are as given in Figure. Some additional requirements are detailed in the following paragraphs.. GOOD CEMENT MORTAR: The cement mortar should e used in the ratio of part of cement with 6 parts of sand ( sack of cement mixed with 6 equal sacks of sand).. HORIZONTAL SEISMIC BANDS:. Lintel Band. Roof/ Floor Band. Vertical reinforcing ar at corner 4. Door 5. Window 6. Plinth Band 7. Window Sill Bands (in all Important Buildings only) Figure : Essential Internal Elements in Buildings for Earthquake Safety A seismic and consists of reinforced concrete flat runner through all external and internal masonry walls at the following levels in the uilding. a. at the plinth level of the uilding. at the levels of lintels of doors and windows c. at the ceiling level of roofs consisting of wooden joists or, prefaricated reinforced concrete eams or, planks. (Such and will not e necessary if the roof consists of Reinforced Concrete or, Reinforced Brick slas cast on the walls covering a minimum of / of the thickness of the wall.) The dimensions of the and and the reinforcement inside depend upon the length of the walls etween the perpendicular cross walls. The tale elow (Tale-) shows the dimensions to e adopted for the seismic ands and the internal reinforcement details to e provided. The reinforcement and ending details of seismic ands are given in the Figure-. Reinforcing ars will e of Fe 45 type [TOR or, High Yield Strength Deformed, i.e. HYSD ars] The details given here are extracted from IS: Code of Practice as applicale to uildings with Brick/ Concrete lock walls and R.C. flat sla roofs. Details not given here may e seen in the Code.

6 @50 6@50 (a) () (c) (d) (e) (a) Section of the Band with longitudinal steel ars () Section of the Band with 4 longitudinal steel ars (c) Structural Plan at L- type wall junction (d) Structural Plan at T- type wall junction (e) Dimensional view of the L - type wall junction (f) Dimensional view of the T - type wall junction Figure-: Reinforcement and Bending Details of Seismic Bands (f). Longitudinal reinforcements. Lateral Ties. Vertical reinforcement at corners,, Wall thickness Tale-: Recommended size and longitudinal steel in Seismic Bands (Zone IV) Internal length of Residential uildings Important Pulic Buildings (Schools, Hospitals, Meeting Halls, Anganwadis, etc.) wall Size of the and No. of Bars Dia (mm) Size of the and No. of Bars Dia (mm) 5 m or, less 0 cm x wall width 8 0 cm x wall width 0 6 m 0 cm x wall width 0 0 cm x wall width 7 m 5 cm x wall width cm x wall width m 5 cm x wall width cm x wall width 4. VERTICAL REINFORCEMENT IN THE BRICK WALLS: For earthquake safety in seismic zone IV reinforcing ars have to e emedded in rick masonry at the corners of all the rooms and the side of the door openings. Window openings larger than 60 cm in width will also need such reinforcing ars (Figure 4). The diameter of the ar depends upon the numer of storeys in the uilding. The recommendations are given in Tale-. Providing the vertical ars in the rickwork and concrete locks requires special techniques which could e easily learnt y the supervising engineers and masons will need to e trained.

7 These vertical ars have to e started from the foundation concrete, will pass through all seismic ands where they will e tied to the and reinforcements using inding wire and emedded to the ceiling and/roof sla as the case may e using a 00 mm 90 end. Sometimes the vertical ars will not e made in one full length. In that case the extension of the vertical reinforcement ars are required, an overlap of minimum of 50 times the ar diameter should e provided. The two overlapped reinforcement ars should e tied together y using the inding wires. Tale-: Recommended size of vertical steel in Seismic Bands (Zone IV) No. of storeys Floor Residential uildings * Important Pulic Buildings * (Schools, Hospitals, Meeting Halls, Anganwadis, etc.) Dia of Single HYSD(TOR) Bar at corners of room (mm) Dia of Single HYSD (TOR) Bar at corners of room (mm) One - 0 Two Top 0 Bottom 6 Top 0 Three Middle 6 Bottom 6 * Building of four storey though permitted in Zone IV, ut not desirale. /4 /4 /4 (a) () a & : Alternate courses in one rick wall : One rick length ½ : Half rick length ¼ : Quarter of a rick length ¾ : Three quarters of a rick length : Vertical reinforcement ars with Concrete/ mortar filling in pocket of M0 grade (:½: nominal mix) Figure-: Typical Details of Providing Vertical Steel Bars in Brick Masonry Tale-: Recommended joint details with the vertical reinforcement at corner for masonry walls using different kind of materials Type of Joint Corner reinforcement in case of Brick Masonry Corner reinforcement in case of Solid Concrete Block Masonry /4 /4 /4 Corner reinforcement in case of Hollow Concrete Block Masonry (see the hole and slit made) L- Joint T- Joint

8 4. VERTICAL REINFORCEMENT AT JAMBS OF OPENINGS: All door and window openings wider than 600 mm will have vertical reinforcement in jams as shown in Figure-4. (a) Sectional Elevation of Door () Sectional Elevation of Window (c) Section - Figure-4: Typical Details of Providing Vertical Steel Bars around doors/windows 5. FOUNDATION Foundation width 'B' should e decided y the load coming on the foundation and the earing capacity. Masonry width may e reduced y ½ times T in every step of 50 mm height. NOTE: In sandy soils with high water tale within 8 m depth elow ground level, which may get liquefied during earthquake of MSK intensity VIII, pile foundation need to e used in consultation with the Structural/ Geotechnical Engineer. Masonry in C.M.:6 Masonry in C.M.:6 Well compacted Sand P.C.C :4:8 Floor Finish Plinth Band Plinth Level < 5 T.5 T T 6mm c/c 00 TOR Ground Level T - 0 for Brick Work 00 for Block Work < Figure-5: Foundation Detail with Plinth Band in Brick or, Concrete Block Masonry WELL COMPACTED SOIL B Prepared y: Professor Anand S. Arya and Jnananjan Panda Tel: ; anand.s.arya@undp.org, jnananjan.panda@undp.org National Disaster Management Division, Ministry of Home Affairs, North Block, New Delhi, India Tel: ; Tel/Fax: ; Fax: ; ndmindia@nic.in; dsdm@nic.in; Wesite: Prepared under the GoI UNDP Disaster Risk Management Programme

9 EARTHQUAKE SAFE CONSTRUCTION OF MASONRY BUILDINGS Simplified Guideline for All New Buildings in the Seismic Zone V of India Zone V Introduction: As usual new construction of uildings under IAY, Prime Minister Rojgar Yojana and uildings under various other National and State schemes get started in the month of May. The Ministry of Home Affairs is keen that All New Buildings should e made earthquake resistant in the first instant so that we do not add to the stock of existing unsafe uildings. Since most of the uildings are constructed using rickwork or, solid hollow concrete locks with flat roofs, very simple illustrated guidance is provided in the attached rochure for incorporating the earthquake resistant features suitale for seismic zone V. Essential Elements for Earthquake Safety : The essential elements required to make a uilding earthquake safe are as given in Figure. Some additional requirements are detailed in the following paragraphs Lintel Band. Roof/ Floor Band. Vertical reinforcing ar at corner 4. Door 5. Window 6. Plinth Band 7. Window Sill Bands Figure : Essential Internal Elements in Buildings for Earthquake Safety. GOOD CEMENT MORTAR: The cement mortar should e used in the ratio of part of cement with 4 parts of sand ( sack of cement mixed with 4 equal sacks of sand).. HORIZONTAL SEISMIC BANDS: A seismic and consists of reinforced concrete flat runner through all external and internal masonry walls at the following levels in the uilding. a. at the plinth level of the uilding. at the levels of lintels of doors and windows c. at the ceiling level of roofs consisting of wooden joists or, prefaricated reinforced concrete eams or, planks. (Such and will not e necessary if the roof consists of Reinforced Concrete or, Reinforced Brick slas cast on the walls covering a minimum of / of the thickness of the wall.) The dimensions of the and and the reinforcement inside depend upon the length of the walls etween the perpendicular cross walls. The tale elow (Tale-) shows the dimensions to e adopted for the seismic ands and the internal reinforcement details to e provided. The reinforcement and ending details of seismic ands are given in the Figure-. Reinforcing ars will e of Fe 45 type [TOR or, High Yield Strength Deformed, i.e. HYSD ars] The details given here are extracted from IS: Code of Practice as applicale to uildings with Brick/ Concrete lock walls and R.C. flat sla roofs. Details not given here may e seen in the Code.

10 @50 6@50 (a) () (c) (d) (e) (a) Section of the Band with longitudinal steel ars () Section of the Band with 4 longitudinal steel ars (c) Structural Plan at L- type wall junction (d) Structural Plan at T- type wall junction (e) Dimensional view of the L - type wall junction (f) Dimensional view of the T - type wall junction Figure-: Reinforcement and Bending Details of Seismic Bands (f). Longitudinal reinforcements. Lateral Ties. Vertical reinforcement at corners,, Wall thickness Tale-: Recommended size and longitudinal steel in Seismic Bands (Zone V) Internal length of Buildings of all types i.e., Residential uildings & Pulic Buildings (Schools, Hospitals, Meeting Halls, Anganwadis, etc.) wall Size of the and No. of Bars Dia (mm) 5 m or, less 0 cm x wall width 0 6 m 0 cm x wall width 7 m 5 cm x wall width m 5 cm x wall width 4. VERTICAL REINFORCEMENT IN THE BRICK WALLS: For earthquake safety in seismic zone V reinforcing ars have to e emedded in rick masonry at the corners of all the rooms and the side of the door openings. Window openings larger than 60 cm in width will also need such reinforcing ars (Figure 4). The diameter of the ar depends upon the numer of storeys in the uilding. The recommendations are given in Tale-. Providing the vertical ars in the rickwork and concrete locks requires special techniques which could e easily learnt y the supervising engineers and masons will need to e trained.

11 These vertical ars have to e started from the foundation concrete, will pass through all seismic ands where they will e tied to the and reinforcements using inding wire and emedded to the ceiling and/roof sla as the case may e using a 00 mm 90 end. Sometimes the vertical ars will not e made in one full length. In that case the extension of the vertical reinforcement ars are required, an overlap of minimum of 50 times the ar diameter should e provided. The two overlapped reinforcement ars should e tied together y using the inding wires. Tale-: Recommended size of vertical steel in Seismic Bands (Zone V) Buildings of all types i.e., Residential uildings & Pulic Buildings * (Schools, Hospitals, Meeting Halls, Anganwadis, etc.) No. of storeys Floor Dia of Single HYSD(TOR) Bar at corners of room (mm) One - Two Top Bottom 6 Top Three Middle 6 Bottom 6 * Building of four storey not permitted in Zone V. /4 /4 /4 (a) () a & : Alternate courses in one rick wall : One rick length ½ : Half rick length ¼ : Quarter of a rick length ¾ : Three quarters of a rick length : Vertical reinforcement ars with Concrete/ mortar filling in pocket of M0 grade (:½: nominal mix) Figure-: Typical Details of Providing Vertical Steel Bars in Brick Masonry Tale-: Recommended joint details with the vertical reinforcement at corner for masonry walls using different kind of materials Type of Joint Corner reinforcement in case of Brick Masonry Corner reinforcement in case of Solid Concrete Block Masonry /4 /4 /4 Corner reinforcement in case of Hollow Concrete Block Masonry (see the hole and slit made) L- Joint T- Joint

12 4. VERTICAL REINFORCEMENT AT JAMBS OF OPENINGS: All door and window openings wider than 600 mm will have vertical reinforcement in jams as shown in Figure-4. (a) Sectional Elevation of Door () Sectional Elevation of Window (c) Section - Figure-4: Typical Details of Providing Vertical Steel Bars around doors/windows 5. FOUNDATION Foundation width 'B' should e decided y the load coming on the foundation and the earing capacity. Masonry width may e reduced y ½ times T in every step of 50 mm height. NOTE: In sandy soils with high water tale within 8 m depth elow ground level, which may get liquefied during earthquake of MSK intensity VIII to IX, pile foundation need to e used in consultation with the Structural/ Geotechnical Engineer. Masonry in C.M.:4 Masonry in C.M.:6 Well compacted Sand P.C.C :4:8 Floor Finish Plinth Band Plinth Level < 5 T.5 T T 6mm c/c 00 TOR Ground Level T - 0 for Brick Work 00 for Block Work < Figure-5: Foundation Detail with Plinth Band in Brick or, Concrete Block Masonry WELL COMPACTED SOIL B Prepared y: Professor Anand S. Arya and Jnananjan Panda Tel: ; anand.s.arya@undp.org, jnananjan.panda@undp.org National Disaster Management Division, Ministry of Home Affairs, North Block, New Delhi, India Tel: ; Tel/Fax: ; Fax: ; ndmindia@nic.in; dsdm@nic.in; Wesite: Prepared under the GoI UNDP Disaster Risk Management Programme