Concept on positioning of Columns

1. Ans

Investigation of the framing plan with respect to Symmetry in X-direction:

If we split the plan vertically half, it will look mirrored. So, we

conclude the given plan is symmetric in X-direction.

Investigation of the framing plan with respect to Symmetry in Y-direction:

If we split the plan horizontally half, it will look mirrored. So, we conclude the given plan is symmetric in Y-direction.

Investigation of the framing plan with respect to redundancy in X-direction

The columns in x-direction are comparatively more and evenly spaced. So, the structure is more redundant in x-direction. Except the top and bottom column rows are having quite longer spans.

Investigation of the framing plan with respect to redundancy in Y-direction.

The columns in y-direction are comparatively lesser but evenly spaced. So, the structure is redundant but lesser than that of in x-direction.

INVESTIGATION WITH RESPECT TO BI-DIRECTIONAL STIFFNESS:

1.the column in horizontal direction is connected with straight-to-straight beams. this means any lateral load (seismic force in x-direction) passing from left end of the building will have its path straight till it reaches right end of the building so no or less possibility of force divers on take place.

2. the column in vertical direction is not connected with straight-to-straight beams .so a lateral load passing from south side of building will get diverted to east & west direction to reach next bay. there will be major force diversion take place with seismic force in y-direction. the framing plan is weak with respect to bi-directional stiffness in y- direction

INVESTIGATION OF THE FRAMING PLAN WITH RESPECT TO DUCTILITY:

1.prima face the aspect ratio of the plan clearly hints more column in x-direction compared to y- direction .it will result in higher stiffness of the building in x-direction, which would reduce ductility in x-axis

2.moreover the x-force will easily pass from one bay to its next due to beam alignment whereas, the y- forces will struggle to pass through the north -south beams are arranged in zig-zag which leads to a discontinuous bracing.

3. we can conclude that the given framing plan is more ductility in y- direction than of in x-direction

2.ANS

VERTICAL IRREGULARITY:

the building plan area is large in bottom stories. the floor plan areas are getting reduced with increase in height. these building offsets has to be crosschecked with reference IS-1893-2016 table -6serial number 3

SOFT STOREY:

the building has uncovered opening space in 6th floor. as there is no occupancy or a partition walls, this lead to plastic hinge formation at the columns (with reference to IS -1893-2016 figure4A). this has to be checked and sufficiently designed.

slopy base:

the building is constructed on a sloping ground at one side this will lead to significant variations in the stiffness (with reference to IS-1893-2016 figure5E) few levels may be subjected to soft Storey mechanism

3.ANS

OPEN GROUND FLOOR- this denotes soft Storey mechanism acting in the building

ROOMS ALONG 2BAY SEPERATED BY AN OPEN CORRIDOR- the bays filled with rooms will have higher mass compared to the middle bay left open for corridor. this induces mass irregularity along height uniformly

TWO SHORT SIDES COVERED WITH INFILL WALL-this means the building's lest and right sides periphery is more stiffer during seismic forces (especially along north-south)

STAIRCASE PORTION AT LEFT TOP CORNER- usually staircase and lift portions are stiffer than other parts because of concentrated concrete elements. so the staircase portion contains more stiffness in the provided building plan

NO FRAMING CONNECTIONS ALONG Y-DIRECTION- we could see no structural beams provided along the vertical direction between columns this makes the building more vulnerable during the north-south seismic force

BEAMS CONNECTED ALONG COLUMN MINOR AXES- the column are having longer dimensions in y- direction this means they are stiffer along y-direction but beams are running only along x-direction which would attract much lesser lateral forces and hardly transfers it

VARIATION IN COLUMN SIZES- the internal columns are having higher sizes compared to exterior columns (this is common because of higher load demands) but this will lead to significant difference in lateral drift of columns so the concrete floor might have suffered heavy out-of -plan shear which would lead to collapse