DESIGN REPORT
PROPOSED RESIDENCE AT BUYUNI, MTIMWEUPE,
PEMBAMNAZI, KIGAMBONI, DAR ES SALAAM
Table of Contents
1
REPORT ON DESIGN .............................................................................................................................. 1
1.1
Introduction .................................................................................................................................. 1
1.2
Design Standards .......................................................................................................................... 1
1.3
Material Specifications.................................................................................................................. 1
1.4
Structural System Description ...................................................................................................... 1
1.5
Load Assumptions ......................................................................................................................... 2
1.5.1
Dead Loads ............................................................................................................................ 2
1.5.2
Live Loads .............................................................................................................................. 2
1.5.3
Load Combinations (per BS 8110) ......................................................................................... 2
1.6
2
Conclusion and Recommendations............................................................................................... 2
FRAME AND SHELL ANALYSIS AND DESIGN .......................................................................................... 3
2.1
SOFTWARE MODEL ....................................................................................................................... 3
2.2
ANALYSIS RESULTS ........................................................................................................................ 6
2.2.1
2.3
3
Reaction at the foundation bases results ............................................................................. 6
BEAMS ANALYSIS AND DESIGN ..................................................................................................... 7
CALCULATION SHEETS ATTACHMENT ................................................................................................. 10
1 REPORT ON DESIGN
1.1 Introduction
This structural design report presents the analysis and design of a Proposed Residence at
Buyuni, Mtimweupe, Pembamnazi, Kigamboni, Dar es Salaam. It outlines the structural
systems, materials, design assumptions, and loading criteria employed to ensure safety,
functionality, and compliance with applicable codes and standards.
The reinforced concrete structure includes foundations, columns, beams, slabs, and a staircase
system, designed in line with BS 8110 (1997). Materials consist of C25 grade concrete and
high-yield reinforcement steel with a yield strength of 460 N/mm², suitable for residential use
under standard occupancy conditions.
1.2 Design Standards
The design follows British Standard BS 8110: Part 1 (1997), supported by additional
references as shown:
Standard
BS 8110: Part 1 (1997)
BS 8004 (1986)
BS 6399
BS 8666 (2005)
BS 4449
BS 882
BS 12
Description
Structural use of concrete
Foundations design
Loading for buildings
Reinforcement scheduling, bending, and cutting
High-yield reinforcement steel specification
Aggregates for concrete
Ordinary Portland Cement specification
1.3 Material Specifications
Material
Concrete
Reinforcement
Aggregates
Cement
Water
Specification
Grade C25 (25 N/mm² at 28 days), complying with BS 8110
High-yield steel (460 N/mm²), conforming to BS 4449
Natural crushed stone and sand in accordance with BS 882
Ordinary Portland Cement per BS 12
Clean, free of impurities, suitable for mixing and curing
All materials are selected for durability and performance under site-specific environmental
conditions.
1.4 Structural System Description
Element
Description
Foundations Isolated pad footings based on allowable bearing pressure
Columns
Reinforced concrete, rectangular or square in cross-section
1
Beams
Slabs
Staircase
RC beams spanning between columns to support slabs
Cast-in-situ solid RC slabs acting compositely with beams
Reinforced concrete dog-legged staircase integrated into the structure
This system ensures robustness, ease of construction, and alignment with standard residential
architecture.
1.5 Load Assumptions
1.5.1 Dead Loads
Item
Concrete self-weight
Floor finishes
Ceiling finishes
Internal partitions
Load (kN/m²)
24 kN/m³ (density)
1.0
0.5
As per architectural layout
1.5.2 Live Loads
Area
Load (kN/m²)
Residential floors
2.0
Staircases and landings 3.0
1.5.3 Load Combinations (per BS 8110)
Limit State
Combination
Ultimate Limit State
1.4Gk + 1.6Qk
Serviceability Limit State Quasi-permanent and frequent combinations
1.6 Conclusion and Recommendations
The structural design of the proposed residence is consistent with BS 8110: Part 1 (1997) and
supporting standards. All structural components—foundations, columns, beams, slabs, and
staircase—have been analyzed and detailed to ensure safety, serviceability, and constructability.
2
2
FRAME AND SHELL ANALYSIS AND DESIGN
2.1 SOFTWARE MODEL
Figure 1 ISOMETRIC VIEW
3
Figure 2 FRONT VIEW
Figure 3 RIGHT SIDE VIEW
4
Figure 4 REAR SIDE VIEW
Figure 5 LEFT SIDE VIEW
5
2.2 ANALYSIS RESULTS
2.2.1 Reaction at the foundation bases results
Figure 6 Base reactions
Figure 7 Base reactions beneath the basement section
6
2.3 BEAMS ANALYSIS AND DESIGN
Figure 8 FIRST FLOOR BEAMS ANALYSIS (left) VS DESIGN (right)
7
Figure 9 GROUND FLOOR BEAMS ABOVE THE BASEMENT BEAMS ANALYSIS(right) VS DESIGN (left)
8
Figure 10 ROOF FLOOR BEAMS ABOVE THE BASEMENT BEAMS ANALYSIS(right) VS DESIGN (left)
9
3 CALCULATION
SHEETS
ATTACHMENT
10
FOUNDATION FOOTING DESIGN
Design data
Axial load due to service loads
Axial load due to ultimate loads
(From ETABS model analysis results)
(From ETABS model analysis results)
Characteristic concrete strength
Characteristic of reinforcement
Net permissible ground bearing pressure
Column width
Column depth
Concrete cover
Base plan area
Minimum required base area
Base length for square base
Provided length of the square base
Earth pressure due to ultimate loads (q)
Base thickness
Assumed base thickness
Bar size
(Exposure condition is severe)
Table 3.3
Effective depth
(Note: This is the mean effective depth since the main
reinforcement runs in both directions)
11
Bending
Check bending at the column face
Clause 3.11.3.1
Clause 3.4.4.4
Bending length due to earth
pressure
Bending force
Bending moment
Bottom reinforcements
Bar spacing
Minimum % reinforcements required =
Provide Y12-200 c/c
0.13
Table 3.25
Maximum spacing
Clause 3.12.11.2.7
12
Shear resistance
Shear capacity
(Clause 3.5.6 and Clause 3.7.7)
Direct shear
Clause
3.7.7.4
Checking the direct shear at a distance of 1.0d from the column face.
If the shear stress v is less than vc then no shear reinforcement is required
Shear force
Shear stress
Punching shear
Clause
3.7.7.2
The possibility of punching shear is checked checked at the
column face for the maximum shear stress as indicated in Clause
3.7.7.2 and on a perimeter located at 1.5d from the column face
as indicated in Clause 3.7.7.6. If the calculated shear stress does
not exceed vc on this perimeter then no further checks are
required.
Shear stress
Column perimeter
13
Clause
3.7.7.6
Shear at 1.5d from the face of the column
Critical perimeter
Area within the critical perimeter
Shear force outside the critical area
Clause
3.7.7.2
Shear stress
14
BIAXIAL COLUMN DESIGN AS PER BS 8110-1997
DESIGN DATA
Column width
Column depth
Column height
Design data from ETABS
software analysis results
Ultimate design load
CHECKING IF THE COLUMN IS SHORT
Top beam depth
Bottom beam depth
Effective length
15
Short or slender
Clause 3.8.1.3
Since both ratios are less than 15, the column is short.
Longitudinal steel
Diameter bar
Diameter of link
Equation 1
Equation 2
Enhanced design moment about x-x axis, Mx', is
16
From N-M interaction charts
100Asc/bh=
Links
Clause 3.12.7.1
Provide 4Y16
Link spacing
17
FLOOR SLAB DESIGN
Slab thickness
Self weight
Characteristic total dead load
Characteristic imposed load
Concrete grade
Characteristic strength of
reinforcing steel
Effective depth
Bar diameter
Cover
The effective depth for the outer layer
The effective depth for the inner layer
Breadth
Slab designed per 1 m width
Design loading
Ultimate design load
REINFORCEMENTS IN THE X-DIRECTION
Position 1
Table 3.14
Position 2
18
Position 1 (continuous edge)
Clause 3.5.3.4
< 0.156
Clause 3.4.4.4
section is singly reinforced
The lever arm is limited to 0.95d
Provide T10-250 c/c
Position 2 (mid-span)
Clause 3.5.3.4
< 0.156
Clause 3.4.4.4
section is singly reinforced
The lever arm is limited to 0.95d
19
Provide T10-250 c/c
Position 3 (discontinous edge)
At least 50% of bottom steel should be provided in the top
at the support and not less than the minimum area required
SHEAR RESISTANCE
Clause 3.5.5
position 1
position 3
Clause 3.12.10.3
Table 3.15
Position 1(continuous edge)
Shear stress
Clause 3.5.5.2
Maximum shear
20
Shear stress limit check
Shear capacity of the section
Table 3.8
REINFORCEMENTS IN THE Y-DIRECTION
Position 1
Table 3.14
Position 2
Position 1 (continuous edge)
21
Clause 3.5.3.4
< 0.156
Clause 3.4.4.4
section is singly reinforced
The lever arm is limited to 0.95d
Provide T10-250 c/c
Position 2 (mid-span)
Clause 3.5.3.4
< 0.156
Clause 3.4.4.4
section is singly reinforced
The lever arm is limited to 0.95d
22
Provide T10-250 c/c
SHEAR RESISTANCE
Clause 3.5.5
position 1
position 3
Table 3.15
Position 1(continuous edge)
Shear stress
Clause 3.5.5.2
Maximum shear
Shear stress limit check
Shear capacity of the section
Table 3.8
23
Deflection check
Table 3.9
Clause 3.4.6
The beam is simply supported
There is no moment redistribution
Clause 3.4.6.5
Service stress
Modification factor
Extract from Table 3.10
X Table
3.10 value
24
25