Conceptual design of a building with columns and shear walls

Question 1:
The building shown, 20 × 35 m in plan, has columns on a 5 × 5 m grid and shear walls (with dimensions shown in m, 250 mm in thickness) in three alternative arrangements, (a), (b), (c), all with the same total cross-sectional area of the shear walls. Compare the three alternatives, taking into account the restraint of floor shrinkage, the lateral stiffness and the torsional one with respect to the vertical axis, the vertical reinforcement required for the same total flexural capacity at the base, the static eccentricity, the system’s redundancy, foundation systems, architectural constraints etc.

Question 2:
Discuss the suitability for earthquake resistance of the moment resisting framing plan of a three-storey building depicted here (cross-sectional dimensions in cm), the eccentricity of the centre of mass (as centroid of floor plan) to the centre of stiffness (from the moments of inertia of the columns) are shown. Suggest an alternative. Also, is there torsional flexibility? Are the two fundamental translational modes of vibration larger than the fundamental torsional mode of vibration. Discuss qualitatively.

Issues in the given framing plan:

Indirect lateral load transfer in X and Y direction – the beams are connecting to another beams mixes ineffective during natural loads transfer in such condition, the primary beam is prone to shear failure

Eccentricity, the longer the distance the distance between center of mass and centre the centre of stiffness, the high the higher torsional moment off the building come on as per the given plan eccentricity, the building is subjected to higher torsional and moment (torsional flexibility ) invert x and y directions.

Strong beam weak column possibility – the size of column majorly mentioned as 25 cm x 25 cm but all the beams have much deeper section 50 cm. Inertia of beam is visually higher than column. If the column reinforcement is adequately greater than that of beams, we are OK And since we do not have the reinforcement details, this is doubtful It is recommended to have slight bigger size of column

Question 3:

A multi-storey building with basement, with a quadrilateral (non symmetrical floor plan) plan as, has interior columns in an irregular (not in a grid) pattern in plan that serves architectural and functional considerations. Partition walls and interior beams supporting the slab have different layout in different stories. However, there is no constraint to the type, location and size of the lateral force resisting components and sub-systems on the perimeter. Proposals are to be made and justified for the choice of the lateral-load-resisting system and its foundation.

Observation in the given framing plan:

Floor Plan – the floor plan of building is not either uniform or symmetric. So naturally any lateral load induced in the floor will not have 100%. Influence in same direction definitely a special lateral load resisting system for these torso movement should be accommodated.

Random Internal Columns – since the internal column random they are unable to transfer lateral load efficiently and they cannot achieve desirable building response, so we have to assume and design those columns for only gravity loads.

Floor to floor variations in partition walls and beams – partitions walls provide an important mass control in a building and beams Play keep roll in shear transfer from floor to beam. All these elements are not in order. So heavy distortion and distribution of lateral load will happen

Suggestions on the lateral load system and its foundation

• Heavy tar snug pores should be controlled by respective lateral load system. So corners shear walls are suggested
• The proportion of lower area is greater on the left side than the right side Irregular quadrilaterals. So corner here was on the left side should be heavier than right..
• Corner sheer walls shall preferably be supported over a box foundation. Sheer walls should be connected by link beams to transfer sheer from one to the other.
• The internal column shall be supported by isolated footing. Those isolated footing can be connected with sheer walls through tie beams