Concept on positioning of Columns

OBJECTIVE OF CHALLANGE:

• to understand te impact of verticle and horizontle member in seismic behavior of astructure
• to understand diff irregularities in a building

1)

ANS:

investigation of the framing plan with respect to symetry in X-direction

if we split the plan vertically half , it will look mirrired . so we concluded the given plan is symetric in X-direction

investigation of the framing plan with respect to symetry in Y-direction

if we split the plan horizontally half , it will look mirrired . so we concluded the given plan is symetric in Y-direction

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

the columns in X-direction are comparativly more and evenly spaced so te structure is more redundant in X- direction .Exept the top bottom column row are having quite longer span

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

the columns in Y-direction are comparativly Lesser than but evenly spaced so te structure is redundant in Y- direction but lesser than x-direction

investigation with bi direction stiffness

the column in horizontle direction are connected with strigth to strigth beam , this means any lateral loads (seismic force in x-direction) passing from left end of building will have its path stright till it reaches right end of the building .so no or less possibility of force diversion take place

the column in verticle direction are not connected with stright to stright beams.so lateral load i passing from south side of building to east wet s direction to reach next bay , there will be next forcee diversion take place with seismic force y- direction . the framing plan is week with respect to bi directional stiffness in y- direction

investigation of the framing plan with respect to ductility

prime facie , 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- direction

morever thhe x- force will easily pass from one bay to its next due to beam alignment. where as 5the y- force will strugle to pass through the north sout beam are arrranged in z555i555g za5g5 which leads to discoutinious bracing

we can conclude that the given framing plan is more ductile in y- direction tan that in x- direction

2)

verticle irregularity: the building plan area is large bottom stories the floor plan areas are getting reducv with incere in hw=eightb these building offset has to be cross checked with the referance to is -1893 -2016 table-6 serial no 3

soft story: the building has uncovered opening space in 6th floor as tere is no occopancy or a partition wall thi will lead to plastic ing formation at the column ( with referance to is -1893 -2016-4A) this has to be cecked and sufficiently designed

slopy base: the building iss constructed on sloping ground at one side. this will lead to significant variation in the stiffness ( with referance to is-1893 -2016 fig: 5E) few levels may be subjected to soft story mechanism.

3)

open ground floor : tis denotes soft story mecanism acting in the building

room along 2 bay saprtarted by an open corridoor : the bay filled with room will ave higher mass compared to th emidle bay left open for coridoor this induse masss iregularity along height uniformly

two short sides covered wiyh infill walls : this means th e buildings let and right periferi is more stiffer during seismic forces ( especially along north -south)

staircase portion at left top corner : usually staircase and lifr are high stiffer than other part beacause of concentrated conctrete element so the stair case portion contains more stiffness in the provided building plan

no framing connection along y- direction: w e could see no structural beams are provided along y- direction betwwen column this make the building more vunarable during north south seismic force

beam connected alomg column minor axes:the column having longer dimension in y direction this mean sthey are more stiffer along y - direction but the beanms are running along x-direction which would attract much lesser lateral force and hardly transfer it

variation in column size: the internal column having higher size compared to the exterior column ( this column beacause of higher load demand ) but this will lead to significant differace in lateral drift of column so the concrete floor might have suffered heavy out of plane shear whuch would lead to collapse