Concept on positioning of Columns
1.
Comment on the layout of the framing plan concerning earthquake resistance in the two horizontal directions X or Y (dots are columns, lines depict beams). Look into aspects of symmetry, redundancy and bi-directional stiffness and ductility.
aim the layout of the framing plan concerning earthquake resistance in the two horizontal directions xandy dots arecolumn lines deplict beams.
answer investigation of the framing plan with respect to symmentry
if we split than plan verrtically half it will look mirriored so coordinate the given plan is symmetric in x direction
investigation of the framming plan with respect to symmetry in y direction
if we split the plan horizontally half it will look mirrored conclude the given plan is syymetric in y direction
investigation of the framming plan with respect to reduntancy in xdirection
the columns in x directionare complimentary and evenly space so the structure is more redduntan in y direction . expect the top and bottom column are having quite longer spans
investigation of the framming plan with respect to redundancy in y direction
the columns in y directions are comparatevely lesser but evenly space so the structure is reduntant but lesser than that of in y direction
investigation with respect to bio directional stiffness
the ccolumns in horizontal directional are connected with straight to straight beams tat means any lateral load passing from left end of the building will have its path straight till its reaches. right end of the building . so no or less
possibility of force diversion takes place
the columns in vertictical direction are not conneccted with straight beams so a lateral load passing from south side of he building will get diverted to east and west direction to reach next bay. there willl be a major forcetakes place with sesmic force in ydirection. the frammin g plan is weak withrespect to bidirectional stiffness in y direction.
investigating of the framing plan with respect to ductility
prima facle, the rspect ratioof theplan clearly hints more column in x- direction comparedd to y directionit will result in higher stiffness of the building in x direction whichwould reduce ductality
we can conclude that the given framing plan is more ductile in y direction than thaat of in x direction
2.What are the possible sources of irregularity in the building shown here? Explain how, as an engineer, each of these irregularities should be dealt with.
vertcal irregualarity the building plan is large in bottom stories. the floor plan area are getting reduced with increase in height the floor plan areas are getting reduced with increase in height these building offsets has to be cross checked with reference to is 1893-2016 table-6 serial number3
soft storey the building hass uncoverred opening space in 6th floor as there is no occupacy or a partition wall this will lead to plastic hinge formation at the columns with reference to is 1893-2016figure 4a this has to be checked and sufficiently designed
softstorey - the building is constrcuted on a slooping ground at one side this will lead to significant variation in the stiffness with reference to 1893-2016 figure 5e few levels may be subjected tosoft storey machanism
verrical irregularity is 1893-2016 table 6
soft storey is 1893-2016 figure 4a
slopy base
3.
open ground floor plan
this denotes soft storey mechanism acting in the building
rooms along 2 bay separated by an open cooridar- the bays filled with rooms will have higher mass comapred to the middle bayleft open to corridar. this includes mass irregularlity along height uniformity
two shorts sides covered with infill walls- this means the buildings left and right sidesperiphery is more stiffer during sesmic forces(espicially north -south)
stair case portion at left top cornor ususlly staircasse and lift partiion are stiffer than other parts because of concentrated concrete elements. so the stair case portion contains more stiffness in the provided building plan
conclid
no framing along y direction- we could see no structural beams provided along the vertical direction between columns. this makes the buildingmore vulnerable during the north-south sesmic forces
beams connected along column mirror axes- the columns having longer dimensions in y directions this means they are more stifferr along y- direction beams are running along x direction which would attrct much lesser laterr forces and hardly transfers it.
variation in column sizes- the internal columns are having higher sizes compae to exterior columns this is common because of higher load combination but this lead to significant differrence in lateral drift column so the concrete floor have suffered heavy out of plane shear which woould led to collapse.