EARTHQUAKE RESISTANT MASONRY BUILDINGS

During Earthquake small residential houses made of conventional brick wall systems are seen to have major effect due to tensional and shear forces caused in various portions of the wall. Due to this various precautions to be taken during construction have been given by various technical  institutes and government agencies from  time to time. In general these should be consulted from structural consultants/ Architects but for places where a consultant is not available a few of the precautions in general are given below:

 

Walls having widths of 8" (200mm) to 9" (230mm) should not be more than 11'9" high and should have vertical as well as horizontal reinforced components.

VERTICAL REINFORCEMENT IN BRICK WALLS

During construction provide vertical reinforcement at corners and T- junctions having dia of 20, 16, 12, 12mm high strength bar ( tor steel bar) respectively starting with 20 dia at G.Floor and reducing respectively at upper floors for a four storeyed building.

The bars should be provided at Corners and at T- Junctions as shown in Figures 1, 2, 3 and 4 above which also show the laying pattern of brickwork at corners and T- Junctions in consecutive layers. The bars should start from the foundation and should pass through all beams and slabs till the last floor,providing proper overlapping of bars. The bars should be encased in reinforced cement concrete of mix M- 15 ie. 1:2:4. Similarly Vertical reinforcement should also be provided around door and window jambs and these should start from plinth beams or roof beams and should continue up to lintel level beam. R.C.C plinth lintel and roof bands should also be provided as given below.

VERTICAL REINFORCEMENT IN BRICK WALLS

PLINTH BAND

As the names indicates this is a R.C.C beam provided at Plinth level ie. below D.P.C level, normally of 75 mm depth when two bars are provided in it and of 150 mm depth when four bars are provided in it. Generally its said that its top should be taken as D.P.C (damp proof course) top but we would prefer if a damp proof course is provided on this, since it shall then help in flooring level at doors where damp proof course is discontinued to maintain same flooring level as inside.

LINTEL BAND

Lintel beam is provided at the top of doors and windows. Its preferable that the top of all doors and windows should be at the same level so that a continuous lintel beam can be provided on all walls.

ROOF BAND

Beam is to be provided below roof on brick walls generally provided where instead of R.C.C or Brick Work slab other roofs such as pitched or wooden roofs are provided. The reinforcement details as per span of walls are given in Chart - 1 below.

 

CHART

 

List of Drawings and type of supervision expected from a Consulting Engineer / Architect

 

For a Layman it’s tough to know what to expect of his Architect and what type of drawings should be expected of him. At times he is also not aware regarding what all he should discuss with his architect. Although all good architects plan and provide the drawings stated below but a very few try to avoid giving many details. Firstly we give below the list of drawings expected of an Architect and what to expect in them.

 

1. Layout Plan

This would show the size of plot and the position and sizes of all the rooms and facilities provided such as bedrooms, drawing room, kitchen, lobby, toilets, store, puja room, study, staircase etc.

2. Layout Plan with Location of Furniture

In addition to the above said plan another layout plan is given showing the location of furniture in all rooms such as sofas, dining table, tables and chairs, beds, Almira, T.V., telephone, music system, computers, dressing table, study table in children rooms, sanitary ware such as W.C., Washbasin tub / bathing area, kitchen showing location of gas, fridge wash sink, location of washing machine and other gadgets/ furniture you expect to use afterwards. In the front and rear location of taps, electrical motor, landscaping etc. The Location of all this should be discussed with the Consulting Engineer / Architect at the initial stage only since it becomes tough afterwards to adjust many things and also then the location of electrical plugs becomes wrong causing you to do surface wiring afterwards. Here this furniture layout plan showing locations to actual scale and size is part of Architects job but the design of individual furniture items is generally taken separately under interior design work.

 

3. Sanitary plans of Toilets

Finalize the location of all sanitary items to go into toilet and also the planning of electrical items such as geyser, hair drier space for keeping shaving/ shampoos brushes etc lights and mirror, exhaust fan towel rails etc connection of jets to w.c. hight till which the tiles/ stone is to be fixed. for this the Consulting Engineer /  architect gives a plan of the toilet and also drawings of each wall detailing the levels and positions of taps / fixtures and light points on each wall. If possible a small cabinet should be provided separately or below the washbasin counter. Providing a counter around the washbasin helps in placing many small items on it or for making your samm child sit on it while you brush them or wash there face etc. Location of floor traps should be indicated with direction of floor slope towards them.

 

4. Drainage Plans

Drainage Plans show the rainwater drainage directions and slopes in open areas at Ground level, Balconies, Terrace and the location of traps and rain water pipes. The location of Sanitary pipes and connections to them from traps and sanitary fittings. Location of Manholes and gully traps, location of any taps given in open area or terrace etc. Location of Drainage pipes connecting manholes and there connection to main manhole with direction of flow and levels and slopes both of pipes, bottom of manholes and gully traps. The levels of ground in open area should be indicated and the levels in balconies and terrace also should be given to detail slopes. Position of any underground tank for water storage. If possible all vertical drainage pipes should be given outside the walls uncovered and if necessary covered afterwards this helps in less damage to the structure both at the time of construction and afterwards in case of any leakage.

5. Electrical Layout

Planning for the electrical layout becomes easier in case location of all appliances and fixtures have been fixed in the above drawings such as bed lights would be positioned near location of bed tv cable point would be given near tv location and telephone jack given near its location. The location of fans and wall lights are also indicated in this plan as the location of mains and electrical meter. Its also given at what levels various switch boards to be given in height and there location as distance from any end of wall so that the electrician does not make a mistake w.r.t. position. It should be decided which make of switches shall be fixed since the type boxes to be fixed in wall shall be for the same make. Its generally seen that people do not decide this earlier and at the last moment ask electrician to get boxes in which at times the switches of the make you decide later do not fix. Always lay separate conduits for electrical wires, telephone cable and cable TV otherwise disturbance is caused in them. In todays date where most of the times the tanks are filled with motors it shall be nice to make provision for an electrical indicator indicating when the tank is full and the indicator should be located near the kitchen or lobby. Make provision for position of Inverters since these have become a standard fitting and location of connection to them. Also the location of an mini EPBX to properly direct all calls and it also functions as an intercom inside the house. Make provision for door phone at gate and if required a security camera below balcony roof or any other convenient location. If you considering providing electronic home security then discuss this with the proper agency and incorporate there electrical requirements in the electrical layout or ask the agency to provide detailed electrical drawings for there items which should then be given to the architect for there integration with his plans

6. Layout of Kitchen

Kitchen planning has become very important today with the incorporation of so many electrical gadgets and cabinetry in it. Here you should inform the Consulting Engineer / architect regarding all things you expect to go in it so that he gives a layout showing location of all of them. Some of the items are Sink here decide its size and type initially since this effects the location of taps, water geyser, water purifier and a cabinet for placing wet utensils. Decide the type of cooking range since this decides the place to be left for it in the counter and also the location of chimney and any ducting to be done for it and the location of exhaust fan and the gas cylinders. Decide the type of fridge, microwave oven, oven, mixer, juicer, toaster etc so that there location and electrical points for them can be finalized and space is alloted for them otherwise half these items do not get space afterwards and are thus packed and rarely used. Many people say these are part of Interior designing but we would say no these are part of Architectural planning since without these planning proper electrical, sanitary and kitchen size planning can not be done. Finally the location of cupboards and there sizes should be fixed. Location of all these items and cupboards should be shown in a separate kitchen layout in which there should also be separate wall drawings indicating location of electrical sanitary and cupboards on them with the fixing pattern of wall tiles to be fixed on walls.

7.Front, Side and Rear Elevations of the building

A beautiful building needs to be designed from both inside and outside at the planning stage only. Front side and rear elevation plans show how the building shall look when seen from various sides and in case you want changes in looks then you need to decide here because any change in elevation changes nearly all your layout plans and location of furniture electrical and sanitary positions in various rooms effected by the exterior change. For example the change in size and location of a window or a balcony can shift the location of electrical points given for air conditioning / coolers the location of doors and subsequently the location of furniture inside These will also effect change in structural drawings discussed later.. Thus all elevations should be finalized at the initial stage. You should also decide the exterior finish since if stone cladding is to be done then extra space for there thickness should be provided around doors and windows. On finalization you can request the architect to prepare an perspective view of the building. Some Consulting Engineer /  architects include making of perspective drawing in there basic fees and some charge extra for it. The elevation drawings are part of the architects work. Consulting Engineer / Architects can also get a model made of your building and generally charge extra in case of small housing projects while they may include its cost in big projects.

9. Details of special Architectural Features

-Here drawings are provided detailing any specialized Architectural features to be provided inside the building or outside the building for enhancing the looks. These are given such as Arches, columns, specially designed walls, domes in roofs etc.

10. Staircase Details

Detailed drawings of staircase giving their plan and sections also details of any special shapes if provided in steps and also the location of their railings

11. Flooring Details

The Consulting Engineer / Architect is required to provide flooring details indicating the designs to be provided while fixing of stone there layout pattern and any inlays details if they are to be done. Also the type and color of the stone to be used. Similarly details to be given in-case of use of wooden or mosaic flooring. A section detail should also be provided indicating the procedure for laying of the specific type of flooring

12. Details of Grills and Gates

Detailed drawings giving designs of steel and stone grills to be fixed in windows, balcony, boundary walls should be provided. Detailed drawings of Gate to be fixed is to be provided by the Architect and to be to the satisfaction of the owner.

13. Landscaping of open area

Landscaping details are to be provided by the Consulting Engineer / architect in case of small projects directly or in case of large projects to be provided in consultation with a separate specialist on landscaping. Again some architects keep this as part of their architectural job included in their fees while some charge separately. In that case you can also hire a specialist separately and coordinate his work with the Consulting Engineer /  architects Layout drawings and vice a versa. Clarify with architect at time of finalizing his fees.

 

14. Submission Drawings

On the basis of the above planning a Submission drawing is made by the Consulting Engineer /  architect for submitting to the Sanctioning Authority for their Approval of the building plans.

15. Construction Drawings

After Approval of building plans by the concerned Authority the Consulting Engineer / architect prepares construction drawings. These detailed well dimensioned layouts of the building issued for construction purposes to the builder. Here plans for all levels are given in addition to the drawings discussed above.

16. Structural Drawings

Structural drawings are prepared by Structural Engineers i.e ( Civil Engineers ) after calculating the loads and moments on slabs and other structural components. The engineer then prepares structural drawings providing details of slabs, beams , columns, walls and foundations. These drawings provide details of reinforcement in all slabs, columns, beams walls and foundation and also how they are to be tied and laid. He also provides details regarding the Concrete mix to be used for eg. M 15 ie. 1: 2: 4 ( 1 cement : 2 coarse sand: 4 coarse aggregate). He provides notes on covers to be provided to reinforcement and details spacing of stirrups ( rings) in columns and beams and the distance of curtailment of steel in beams and slabs. Details of cranking distance or the distance to which top steel is to extended into next slab. Thickness of slab and sizes of various structural components. Although most of the Consulting Engineer / Architects provide complete details but some try to avoid providing detailed structural drawings or getting them designed from an structural designer to save money. Always request the architect to get the reinforcement after its laid on the shuttering to be checked by the engineer who designed it before casting of roof or foundations and raft basements. This is also necessary since many steel binders do not follow the drawings properly and could have made mistakes which would weaken the building. The structural designer would be the best person to find defects and suggest rectifications. Do not compromise on this since its your and your family's life at stake. The cost of structural designing and providing its drawings is part of the architects fees.

17. Completion drawing

On the successful completion of the building the architect makes a completion drawing its similar to the initial sanction drawing but incorporates any changes made in the building during construction. This drawing is again submitted to the building authority for getting the Completion Certificate. Summary In the end we would like to say interact with your Consulting Engineer /  architect and inform him of all your needs and aspirations regarding your dream house. We would also like to state that in case you are going to spend a lot after the completion of the building on its Interiors then Hire a Interior Designer at the planning stage of the building or if your Consulting Engineer / Architect also does Interior Designing then finalize him for both the architectural and interior design work in the starting so that you do not make any changes in the building on completion due to the Interior Design and all variations expected are incorporated by the Consulting Engineer / architect at the initial stage before commencing construction. A separate article is also given for the role of architect and builder during construction and precautions to be taken during construction.

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