tRIG RAMP DESIGN
I want to design a ramp so that a loading bay has wheelchair access. The height of the loading bay is 100 cm. I have split the design into two ramps, one with a rise of 75 cm (the maximum recommended rise that meets current safety standards) and the other 25 cm. I have chosen 4.2º of ramp angle which also complies with the standard which must not exceed 4.674º
RAMP RUN AND LENGTH
I use the tan ratio to calculate the run of the first ramp
A = 75/tan 4.2 = 1021.31 cm
We can work out the ramp length using pythagoras
H = √(75^2 + 1021.31^2) = 1024.06 cm
The second ramp has a rise of 25 cm and the same 4.2º angle so the run A
A = 25/tan 4.2º = 340.44 cm and ramp run
H = √(25^2 + 340.44^2) = 341.46 cm
Because the landings are fixed at a minimum of 120 cm, all we have to do now is total it all up.
The total ramp length = 1026.05 + 341.36 + 2 x 120 = 1607.41 cm
Total ramp run = 1021.31 + 340.44 + 2 x 120 = 1601.75 cm
Total ramp run = 1021.31 + 340.44 + 2 x 120 = 1601.75 cm
HANDRAIL
I will calculate the length of the handrail including the 30 cm extensions. The handrail lengths will be the same as the hypotenuses of their triangles (already calculated) plus the lengths of the landings.
Include hand rail = (1607.41 + 30) x 2 = 3274.82
Include hand rail = (1607.41 + 30) x 2 = 3274.82
DESIGN ISSUES
The length of my ramp design is quite long but this also happens at our local Mall. Another design I could use is to 'bend' the ramp around 90º or 180º to reduce its footprint