Concentrated Loads on One/Two-Way Slabs?
Concentrated Loads on One/Two-Way Slabs?
(OP)
Hey fellow structure lovers,
I frequently am posed with the problem of concentrated loads on one-way and two-way slabs. Some of these loads are vertical point loads and some are concentrated moments (through a baseplate). I have no problem performing local area calculations like punching shear. What I'm wrestling with is the bending/torsion calcs (i.e. effective widths).
Aside from plate FEA does anyone know of any references or texts that address this subject? I've been told that Westergaard found that the effective width in a one-way slab with a concentrated load = 2/3*span... but I'd like to have that in writing. Others have suggested guessing or assuming an angle for a triangularly increasing effective width extending from the point of load towards supports.
Help!
I frequently am posed with the problem of concentrated loads on one-way and two-way slabs. Some of these loads are vertical point loads and some are concentrated moments (through a baseplate). I have no problem performing local area calculations like punching shear. What I'm wrestling with is the bending/torsion calcs (i.e. effective widths).
Aside from plate FEA does anyone know of any references or texts that address this subject? I've been told that Westergaard found that the effective width in a one-way slab with a concentrated load = 2/3*span... but I'd like to have that in writing. Others have suggested guessing or assuming an angle for a triangularly increasing effective width extending from the point of load towards supports.
Help!






RE: Concentrated Loads on One/Two-Way Slabs?
b_ef = b_load + 2.4*a*(1.0 – a/L_n)
where:
- ‘b_ef’ is the effective width
- ‘b_load’ is the load width
- ‘a’ is the perpendicular distance from the nearer support to the section under consideration
- ‘L_n’ is the length of clear span
As ‘b_load’ approaches 0 and ‘a’ approaches L_n/2, ‘b_ef’ approaches 60% of L_n.
Any others?
RE: Concentrated Loads on One/Two-Way Slabs?
RE: Concentrated Loads on One/Two-Way Slabs?
This report has charts that give coefficients both for principal and distribution reinforcements for one way slabs subjected to concentrated loads. It has charts to handle overlapping stresses, when wheel loads are parallel or perpendicular to the span. It even takes into account the contact area of the concentrated loads.
Reinforced Concrete Fundamentals by Phil Ferguson has a Chapter On Distribution of Concentrated Loads.
I hope this helps!
RE: Concentrated Loads on One/Two-Way Slabs?