Concept on positioning of Columns

AIM : Concept on positioning of Columns

PROCEDURE :

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.

SYMMENTRY

• The plan is in symmetry, if you see the one of the half portion looks like another half portion in X – direction
• In other words another half portion is looking like mirrored image of upper half
• Now, see it in Y- direction it appears as same as other half of the image, looks like mirrored image of the first object

REDUNDANCY --x-direction

• If we see the image of the plan, the span is longer in x- direction, and also evenly spaced and connected
• And also column are more
• It has more redundancy in x-direction

y—direction

• If we see it in y- direction the span is less when compared to the x-direction
• The columns are less when compared to x-direction
• So, it has less redundancy in y direction

BI-DIRECTIONAL STIFFNESS : X-direction

• Here we can see the column are closely connected
• And there is no gap between the column that is every end of the column is connected to the beam
• If any lateral load is applied it can easily distribute to the last end.
• So there will be least chances of force diversion

Y-direction :

• If we see in Y-direction, some column are connected and some or not
• When the lateral load is applied the load may diverted
• And also leads to travel the in opposite direction
• So, I think it is week in y-dirction

DUCTILITY : X-direction

• We can see that more column are in X-direction when compared to the Y-direction
• By this we can tell that there will be more stiffness in X-direction
• If stiffness is more the ductility will be less

Y-direction

• The column are less less and less stiffnes it leads to more ductility

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.

• VERTICAL IRREGULARITY : there js no continuity in vertical direction,it needs to check the codes which the irregularity in the permissible conditions or not,the codes are is 1893-2016
• SOFT STOREY : there will be no covering with the walls or shear walls in the 6^th floor
• It may leads to formation of plastic hinge
• SLOPY BASE : if we see there will be a slopy base.it leads to variation in stiffness,we want to check it wheather it is in permissible limits

4. A 4-storey hotel building has an open ground floor for the restaurant. Story 2 to 4 have one row of rooms along each long side in plan, separated by a corridor. The two short sides of the perimeter are fully in-filled in all storeys, except for certain openings at the ends of the corridor at storeys 2 to 4 and along the right-hand side of the ground floor. There is a staircase near the upper left-hand corner, with straight flights between landings at floor levels and in-between floors. Cross-section dimensions are written next to the member no. in meters.

Comment on the features of the structural design and of the layout of infills which are important for earthquake resistance and seismic performance. How do they relate to the almost full collapse of this building (the extreme left-hand bay with the staircase survived, as well as one long-side façade in the rear end, and the frame along the right-hand side in plan).

• Open ground floor leads to formation of plastic hinges
• It says that rooms are separated with the corridors, which leads to mass irregularity in the vertical direction
• There is infill walls in the left and right side of the plan, so there will more stiffer in that places in case of earthquake
• Stair case also presents in the top left of the corner of the plan,which leads to more stiffer in that region during an earth quake
• And also the columns are continuously connected with beams in the X-direction and not in Y direction more stiffer in X-direction which leads to problems in transferring of the load in y-direction
• And also more chances to vulnerable in the y-direction when the north south direction seismic forces are occurred
• The column are not in regular shape which will leads to lateral drift of columns where the least column dimensions presents

RESULT :

By this we can understand the how the building behaves with irregularities during an earth quake forces.