GUYANA STANDARD
Part 13 - Foundations and
Excavations
 Scope
 Building Classification
 Site Investigations
 Excavations
 Foundations


- shallow
- deep
SCOPE
This code specifies guidelines for excavations and
foundations for building construction which includes
temporary and permanent excavation for foundation,
drainage system and utilities. This code applies for
low and medium rise buildings.
Building Classification
 Buildings can be classified according to:
-
Use and occupancy
building height (in terms of No. of stories)
Based on use and occupancy, buildings can be
categorized as:
- Residential: Buildings used for domestic
purposes, including private and public housing
- Non Residential: Buildings for non domestic
purposes, such as industrial, commercial or
institutional buildings
Site Investigations
Site investigations shall be conducted for all excavations
and foundations works, as specified in Table 1 below.
Level
1
2
Description
Investigation Details
Remarks
Preliminary
investigation
Test pits, undisturbed
sampling, field and
laboratory testing for soil
identification and
classification
Indicative soil
characteristics
only required
Detailed
investigation
Boreholes, disturbed and
undisturbed sampling, field
and laboratory tests
Detailed soil
report required.
Site Investigations cont’d
For the various categories of buildings the following
investigation shall apply:
 Low Rise Residential Buildings (Class 1) - May require
only Level 1 investigation for the purposes of
excavation and foundation works.
 Medium and high rise residential buildings (classes 2
3) May require both levels 1 and 2 for excavation and
foundation works
 Non Residential buildings (Classes 1-3) Shall require
both Levels 1 and 2 investigation.
Foundations
Design Requirements
Foundation designs for residential buildings shall
be certified by a qualified engineer before approval is
granted. In the design of building foundations, one
of the following methods should be applied:
 Calculation methods for foundations should be
based on the latest edition of BS 8007 and Eurocode 7

Prescriptive methods - based on tables of
allowable bearing pressures
Foundations
 Minimum Depth
Requirements for placement of foundations are:
(a) Minimum depth below ground surface for
bottom of foundation is 300 mm
(b) Building foundations shall not be placed on the
topsoil.
 Materials
Shallow foundations and pile caps for deep
foundation shall be constructed of concrete. Materials
shall be of acceptable quality and shall meet the
minimum strength requirements
Foundations
Materials - cont’d
Concrete - The concrete grade for footings shall be
25 N/mm2 or higher and shall be kept moist for at
least 7 days for curing and the development of design
strength
Reinforcement - The steel for primary
reinforcement shall be high yield bars with a strength
of 410 N/mm2 with a minimum size of 12 mm, and 10
mm for secondary reinforcement. The minimum
cover to reinforcement shall be 50 mm
Shallow Foundations
 Minimum Thickness
The minimum thickness of a shallow building
foundation shall be 250 mm
The prescriptive pressures for Foundations in Sands
and Clays for a minimum depth of 0.6 m below ground
level is given in Tables 6 and 7 respectively in the
Code.
 Settlement
The recommended design limits for settlement in clay
for raft foundations should be 65 – 100 mm, and 50
mm for raft foundations on sand.
Shallow Foundations
 Settlements - cont’d
Table 8 in the Code specifies the Tolerable
difference settlements, for different categories of
buildings of both concrete and steel, and with the
types of damage most likely to occur.
Deep Foundations
 Timber pile foundations shall be provided where the
upper soil strata is of poor strength and poor
compressibility characteristics.
 The minimum recommended dimensions for timber
piles shall be:
(i) minimum butt diameter - 300 mm
(ii) minimum tip diameter - 200 mm
(iii) limiting structural defects such as reverse
bends, twisted grain etc.