Assumptions
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Assumptions TERRACE The size of the terrace to be constructed 71m x 45m . Remove black cotton to approximately 1 m depth . Replace the cotton with a G7/8 imported material from commercial source . Wearing Course - Compact the layers into 150mm layers to a required 93% Mod AASHTO at OMC ( +_ 2% ) ( PI > 6 <12 ) CBR 45 . Special notes : Density allowable to be 150 Kpa . Cut / Fill 1 : 200 on both direction Road Concrete - Internal Road to be Constructed 70 m x 5 m . 150mm Gravel Subbase – Imported ( G6 ) Material Compacted to 95 % Mod AASHTO MOD at O.M.C. 150mm selected subgrade ( G7) Compacted to 93% MOD AASHTO AT OMC Roadbed preparation : Rip insitu to 150 mm and compact insitu to 93% MOD AASHTO AT OMC Concrete : 200mm thick 25 Mpa /19 mm Stone Gravel Access Road Access Road 145m x 5 m 150mm Gravel Wearing Course – Imported Gravel compacted to 93 % Mod AASHTO AT OMC With the PI > 6 < 3GM +10 , MIN CBR = 25 150mm Gravel Subbase – Imported Gravel ( G6 ) Compacted to 95% MOD AASHTO AT OMC
description
CIVIL ASSUMPTIONS
Transcript of Assumptions
Assumptions
TERRACE
The size of the terrace to be constructed 71m x 45m . Remove black cotton to approximately 1 m depth . Replace the cotton with a G7/8 imported material from commercial source .
Wearing Course - Compact the layers into 150mm layers to a required 93% Mod AASHTO at OMC
( +_ 2% ) ( PI > 6 <12 ) CBR 45 .
Special notes :
Density allowable to be 150 Kpa . Cut / Fill 1 : 200 on both direction
Road
Concrete - Internal
Road to be Constructed 70 m x 5 m .
150mm Gravel Subbase – Imported ( G6 ) Material Compacted to 95 % Mod AASHTO MOD at O.M.C.
150mm selected subgrade ( G7) Compacted to 93% MOD AASHTO AT OMC
Roadbed preparation : Rip insitu to 150 mm and compact insitu to 93% MOD AASHTO AT OMC
Concrete : 200mm thick 25 Mpa /19 mm Stone
Gravel Access Road
Access Road 145m x 5 m
150mm Gravel Wearing Course – Imported Gravel compacted to 93 % Mod AASHTO AT OMC With the PI > 6 < 3GM +10 , MIN CBR = 25 150mm Gravel Subbase – Imported Gravel ( G6 ) Compacted to 95% MOD AASHTO AT OMC 150mm Selected layer – Imported Gravel ( G7 ) Compacted to 93 % MOD AASHTO AT OMC Roadbed Prepation : Rip insitu to 150 mm and Compact insitu to 90% MOD AT OMC
Hydrology
The following hydrology data will be used in the design of the storm water drainage
system :
a. Flood return period : 1:5 years for storm water pipe system
(Minor system)
1:25 years for storm water pipe systems
(Major system )
1:50 years for the combined storm water pipe
and road system and low points.
b. Average yearly rainfall : 750mm
c. Minimum time of concentration and runoff coefficient according to :
Design Manual
d. Design method : Rational method for smaller catchments
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4.2 Design Standards The following standards will be used in the design on the drainage system :
a. Minimum : 450 mm diameter
b. Minimum pipe gradient : 0.67%
c. Stormwater details :
Standard Details and
Requirement
d. Pipes laid soffit to soffit
e. Class B bedding ( SABS 1200 – LB ) is to be used as pipe bedding in
trenches
f. Maximum distance between manholes or junction boxes approximately
80.0m
Accessible manhole at each change of direction and at the junction of
different storm water lines
g. Provision must be made to accommodate all roof water
h. Backfill of road crossing with the pipe trenches should be stabilised or Soil
Crete
