formula for concentrated load on a slab
formula for concentrated load on a slab
(OP)
Hello
I am trying to find a formula that I could use in a spreadsheet for the bending-moments of a simply-supported two-way slab under a concentrated-load (similar to equations 10 and 12 of BS8110). The load is 300-mm square.
Any references or guidance would be appreciated.
Regards
I am trying to find a formula that I could use in a spreadsheet for the bending-moments of a simply-supported two-way slab under a concentrated-load (similar to equations 10 and 12 of BS8110). The load is 300-mm square.
Any references or guidance would be appreciated.
Regards






RE: formula for concentrated load on a slab
BA
RE: formula for concentrated load on a slab
Could not see any adaptations of similar loading for plates with various combinations of fixed edges.
Mike McCann
MMC Engineering
RE: formula for concentrated load on a slab
RE: formula for concentrated load on a slab
The slab is simply-supported and allowed to lift at edges. The spans are not equal ranging from 1:1 to 1:4. I am designing a slab 1500:1900mm (1:1.3) but I want to be flexible and cover all ratios, hence a formula.
I have looked at Roarke and the situation I am modelling is referenced under Table 11.4 1c:pg503. If I cannot get a formula I will have to adapt the table for my situation. This is the first time I have used Roarke. Poissons ratio is 0.2 for concrete and the table is for 0.3; how may I adjust for the difference, please? Am I able to extrapolate between the three ratios to obtain a ratio of 1:1.3. I have tested the table and the extrapolation will not be linear.
As a beside; I was given a formula for a concentrated-load on a slab by an engineer I am no longer able to contact. The formula was similar to the BS8110 equations 10 and 11 in that alpha.sx and alpha.sy were the same but nlx2 was replaced with 2.nlx(1/0.3+0.6lx). I am unable to locate a reference to this formula anywhere but I do recognise the 0.3 being the width of the load and the 0.6lx referring to the effective-width from clause 3.5.2.2. I am unable reluctant to use the formula without a reference.
Regards
RE: formula for concentrated load on a slab
I have spoken to the engineer that provided the revised equations 10 and 11. Chris (the engineer) worked out the equivalent-UDL for the concentrated-load and supplemented the equivalent-UDL into equations 10 and 11. I have not done the check but the solution is very elegant. Any load shape on a two-way-slab could be analysed using revised equations 10 and 11 without referring to tables.
Regards