I am back again with some basic analysis, design, costing and construction of a one storey duplex, using a Nairalander project has a case study.

These topic will be divided into substructures and super structures.

Substructure are building member below the building level. These members are foundation, sub structural wall, foundation columns, grade beams and damp proof course (popularly known as German floor).

I am using this particular job because it meet up with basic design criteria.
The site has an extensive soil test, properly done by a good Geotechnical film. I will not be able to post the Geotechnical report here because of copy right,

Summary of sub soil report according to the soil test.
From a depth of 0-750mm firm, dark brownish grey, Sandy, lateritic clay with fine to coarse gravel, silly and Sandy soil was encountered.

From a depth of 0.75- 15m, firm to stiff becoming very stiff to hard brownish grey, molttled, silty, Sandy lateritic with fine to coarse gravel was encountered.

The ground water table at that period of the year was encountered within the borehole at about 3.8m below the existing natural ground level.

The geothermal film recommendation
1. First recommendation, they recommend a reinforced shallow foundation of pads and column placed at a depth of 1.75m below the existing ground level.

2. They also recommend or a a raft foundation in the of raft slab placed at a depth of 1.25m above natural ground level.

The result of the investigation gave a safe bearing capacity of 130kN/m2 at a depth of 1.5m with a factor of safety of 3

Note : this report was carried out by basol associates limited)

Foundation design, while base on similar knowledge, is an exercise of judgements based on the expertise and sometimes based on the experience of the designer.

Some designer can be conservative while others can be innovative, but all foundation must be Safe, cost effective, durable and buildable. These aforementioned factors must be the major objective of every foundation design.

From the recommendations of the geothermal report, I will choose the first one: I, e pad column foundation founded at a depth of 1.75m.

Reasons for this choice are
1. Cost of excavation : it will cost a lot to excavate a trench of 1.2m throughout the entire building area for the raft foundation be built.

2. It will cost more to reinforced a raft foundation founded at a depth of 1.2m

3. The section of the raft slab and beam ( if any) will be much higher than the pad footings - column foundation.

3.cost of labour such as form work etc will be much higher.

4. Speed of construction will be slower compare to pad footing column foundation

following closely.... keep up the good work you guys are doing

Following.

Bring it on abdulwastecx.
A young Engr is ready to learn. I hope you are ready for my questions.

Horlawoomey:
Bring it on abdulwastecx.

A young Engr is ready to learn. I hope you are ready for my questions.

I will try to do justice to them

abdulwastecx:

I will try to do juatice tk them

Good.

Thank God i arrived early and am seated. Engineer, its your PH friend. Always ready to learn.

Very detailed explanation all the time.

princechigzy:
Thank God i arrived early and am seated. Engineer, its your PH friend. Always ready to learn.

Very detailed explanation all the time.

Thanks sir.. . How is that your repair work?

Here is an idealized three dimensional drawings of structural frame of the building

Here is the foundation structural layout :
The layout have the following :
Isolated pad footings
Foundation beam to carry sub structural wall and serve as horizontal tie to link the pad footings around

The two other floors are needed for load estimation. These floors are the ground floor ( damp proof course or oversite concrete), first suspended floor and the roof

These are some of the idealized section

I will start the foundation design by estimating the load on the foundation : this will be done by using a simple two dimensional frame system accros the transverse and longitudinal section.

I will assume that the transverse section is x - x
While the longitudinal section is y-y

I ll take myself out for being present for this lecture• Nice Job Bro

LOAD ESTIMATION ON FRAMED STRUCTURES
(section X-X)

AVERAGE FLOOR LOAD
unit weight of concrete=24kN
depth of slab=0.15m (150mm)
floor finishes=1.2kN/m2
partition allowance=1.5kN/m2
imposed load for residential=1.5kN/m2

w=1.4gk + 1.6qk
Gk: slab selfweight=0.15×24 = 3.60
finishes=1.20
partition allowance=1.50
---------
6.30kN/m2
---------
:• 10 = 1.4(6.3) + 1.6 (1.5)
=11.22kN/m2
approx. ~12kN/m per meter run.

SELFWEIGHT OF FIRST FLOOR SLAB
*assume a dimension of 225mm x 450mm
=0.225 × 0.450 × 24.000
=2.43kN/m3 ×1.4

*assume: 5kN/m for first floor beam.
3kN/m for roof beam
3kN/m for ground floor beam

PARTITION WALL LOAD
》unit weight of 450mm X 225mm X 225mm sandcrete block = 3.47kn/m2
》hight of wall = 2.7m
》weight = 3.47 × 2.7 × 1.4
=13.13kN/m
approx.. ~ 14kN/m

LOAD FROM FLOOR SLAB TO FRAME
First floor slab (asuming a one-way panel)
=3/2 × 3/2 ×12.00 =36kN/m

load on first floor frame; 36 + 13 + 5 = 54kN/m
load on roof beam frame; = 3.00kN
load on ground floor beam frame; 3+ 13 = 16kN/m

horizontal tie grade beam at the foundation level
= 3 + 13/2 =9.5
approx. ~ 10kN/m

Following, sir Abdul, do you work in lagos? Seem most of your jobs are in abuja and environs

jossy26:
Following, sir Abdul, do you work in lagos? Seem most of your jobs are in abuja and environs

We do work in Lagos sir.
I have done some jobs in the east and South South as well. We move round the nation sir

From the above calculation, I have a simple 2 dimensional frame along x-x axis. Remember, my aim is to calculate the total load transmitted into the foundation footing.

Here is the summary of my calculation depicted below with the diagram.

*on top of the building, we have a point load of 10kN from the roof truss. (see, A A). And a uniformly distributed load of 3kN/m which is the self weight of the beam (since the beam is not carrying any further load).

+ at the first floor, we have a uniformly distributed load from the one way slab span, self weight of beams, self weight of portion walls of 2.7m high.

+at the ground floor, we have a floor beam to carries self weight and weight of ground floor beams.

+finally, at the foundation level, we have beams connecting or tieing the isolated pad footings together and also carry in the uniformly distributed load of the foundation or sub structural blocks work of hight 0.9m.

I will be using linpro27 software for static load calculation to analyzed the effect of these load on the idealized two-dimensional truss system to get the supportive reactions at the base of foundation.

abdulwastecx:
I will be using linpro27 software for static load calculation to analyzed the effect of these load on the idealized two-dimensional truss system to get the supportive reactions at the base of foundation.

Pls fellow engineers Expecting a detailed or summarised Results and their interpretation

Baba we are patiently waitinq