Foundations
Standards are the universal language spoken in construction.
Types of standards, International Classification of Standards (ICS)
Foundations are a critical aspect of any construction project,
as they ensure the stability and durability of a structure.
They are designed to support the entire load of the building,
making it essential to thoroughly investigate and understand
the ground conditions before beginning construction.
Proper foundation design requires compliance with
construction standards and regulations to handle the specific
loads and environmental challenges, such as earthquakes.
Additionally, careful consideration must be given to the type of soil,
site survey results, and potential drilling errors that could affect
the foundation’s effectiveness. Addressing these elements properly
can prevent costly mistakes and structural failures,
ensuring the longevity and safety of the building.
Before any construction begins
Site Investigation: Before any construction begins,
a thorough site investigation is conducted.
This step involves assessing the soil condition, topography,
and any environmental concerns that might affect
the stability and design of the foundation.
Obtaining Permits: Acquiring the necessary permits
is a crucial administrative step. This process ensures that
the planned construction complies with local zoning laws,
building codes, and safety regulations.
Project Design: After the initial assessments,
the construction project is carefully designed.
This phase includes drafting detailed architectural and engineering
plans that outline the structure’s layout, electrical systems,
plumbing, and other critical components.
Approval by Chief Architect: Once the design is complete,
it must be approved by the chief architect or the relevant municipal authority.
This step verifies that the project meets all architectural
standards and urban planning requirements.
Execution of Construction: With all approvals in place,
construction can commence. This phase involves the physical building
of the structure, adhering closely to the approved plans and specifications.
Material Selection: Choosing the right materials is fundamental to
ensuring the quality and durability of the construction.
Materials must meet specific standards for strength, durability,
and environmental resistance, appropriate to the loads and conditions of the site.
Each of these steps is integral to the successful completion of a construction project,
ensuring it is safe, compliant, and well-suited to its intended use.
Foundations
MONOLITHIC STRIP FOUNDATIONS
The strip monolithic foundation has a rigid structure with an inextricable
structure that forms a closed contour.
The foundation is laid under load-bearing walls of all types of
buildings built from reinforced concrete structures, wood, and brick.
GEOLOGICAL ENGINEERING REPORT
Geotechnical designers and manufacturers report for construction purposes,
According to the current regulatory framework, with text and graphics
1. Engineering-geological studies ogled on terena
2. Engineering-geological study in the depth of the teren (soundings, etc.,
description of the poison, sample for laboratory research)
3. Vzemana for laboratory research
4.Measures for dealing with geotechnical processes and phenomena, such as:
earthquakes, etc.
5. Investigate harmful chemical elements and impurities in soil
6. Conditions for funding, with data from laboratory and field research for the needs of a specific object.
DRAWINGS OF A MONOLITHIC RIBBON BASE
Work on arranging the strip base begins with the creation of a drawing,
including the main structural elements, dimensions and distances between
individual segments. The depth of the foundation slab (50cm) and the arrangement
of the thermal insulation and waterproofing layer are determined, indicating the
materials used (expanded clay, roofing felt). The location of the formation of
the blind area and plinth is marked, and a diagram of the floor covering is planned.
Work on laying the foundation is carried out using reinforced concrete slabs produced
in accordance with the requirements of the law and standards.
The structures are suitable for use in dry and saturated soils,
they can be laid in the ground at temperatures down to -40°C,
which complies with the recommendations set out in recommendations
and approved standards.
The slabs are suitable for laying strip foundations in areas with
seismic activity up to 9 points. It is allowed to use slabs in soils
that do not contain substances aggressive to reinforced concrete.
Acceptance of slabs is carried out according to the requirements
of the standard, in accordance with the following parameters:
frost resistance;
concrete strength;
compliance with geometric parameters;
water absorption.
Example of a pit drawing
Any foundation construction begins with digging a pit.
It is this initial stage that should be taken into account when designing the structure.
The set of drawings must also include a drawing of the foundation pit.
Let’s look at how to properly dig a foundation pit.
For each type of foundation, there are certain safety data established by Standart.
A similar table can be easily found on the Internet.
Let’s consider a variant of the problem of digging a pit and step-by-step
instructions on how to draw a drawing.
Task. The site has no elevation changes, the absolute value of the existing soil is 51.3.
The 0.000 mark in the conditional value is 52.07. The bottom elevation of the foundation slab is -3,000.
Concrete preparation is provided for placement under a slab, 100 mm thick.
The construction site is not constrained by outbuildings, the soil is loam.
Please note that relative marks in the drawing are usually indicated with two decimal places,
and relative marks with three:
We calculate the absolute elevation of the bottom of the foundation slab: 52.07 – 3.0 = 49.07 m.
We calculate the absolute elevation of the bottom of the pit: 49.07 – 0.1 = 48.97 m.
Pit depth: 51.30 – 48.97 = 2.33 m.
It is most convenient to take the value of 45 degrees as the slope angle of the pit.
Let’s take a look at a step-by-step example of a pit drawing:
We apply a grid on paper consisting of the extreme axes and the contour of the foundation of the pit.
We make an indentation outward of 100 mm from the foundation contour. We get the preparation circuit.
We make an indent of 500 mm outward from the preparation contour.
This figure serves as the permissible minimum slope specified by the standards
(in the previous edition it was 300 mm). This will be the line of the bottom of the pit.
Next, you should make an indent from the border of the bottom of the pit, 2.33 mm.
Since the slopes are inclined at 45 degrees, their height, in plan, is equal to the depth of the pit.
This indentation will serve as the line of the top of the slope. A symbol for the slopes should be
applied on it in the form of a dotted line of long and short lines running perpendicular to the contour.
After the previous step, all unnecessary lines should be deleted. These include: the foundation line
and the preparation contour. Mark the bottom of the pit and mark the ground level.
We carry out the application of the missing dimensions: linking the corners of the pit to the sludge.
We make corrections and notes about the correspondence of relative marks to absolute ones.
If desired, we draw a cross-sectional sketch of the foundation layout indicating all the necessary marks.
Foundations
Pros:
Concrete mixtures placed in various types of structures have good rigidity.
The resistance of the structure to heavy loads, under which it can take on various shapes.
Durability of the structure.
Resistant to sudden temperature changes.
Purchase of materials with a high level of rigidity.
Reinforcement is carried out if it is necessary to protect the foundation from heavy loads,
mechanical damage, stretching, and subsidence.
Thanks to the reinforcement of the foundation, the formation of cracks that can
form when the house shrinks is minimized.
Minuses:
When designing, it is necessary to take into account the increase in
weight of the structure due to the reinforcement of the foundation.
In the process of strengthening an already finished structure,
problems may arise when carrying out work on its reconstruction.
Today, foundations are subject to reinforcement for:
Constructions of monolithic buildings.
Private residential cottages.
Floors.
Calculation of material consumption
In order to calculate the required amount of materials, you should know some parameters:
Width of the foundation.
Its length.
Casting height.
Belt width.
It will be more convenient to look at an example, so in our example the width of the
foundation will be 5 m, length 10 m, casting height 0.3 m, belt width 0.2 m.
First of all, it is necessary to calculate the total volume of the casting.
To do this, using simple formulas, we find out the perimeter of the base,
and then the total volume of the casting by multiplying the perimeter by
its height and the width of the belt.
According to the formula it will look like this:
P = AB + BC + CD + AD = 5 + 10 + 5 + 10 = 30;
V = 30 x 0.3 x 0.2 = 1.8;
But the calculations don’t end there. Having found out the most important parameter –
the volume of the casting, which occupies 1.8 square meters, you should calculate the
volume of the internal part of the foundation, more specifically, what is inside the foundation strip.
To do this, you need to multiply the width and length of the base by the height of the casting,
in the end we get: 5 x 10 x 0.3 = 15 cubic meters – this is the total volume.
Casting volume: 15 – 1.8 = 13.2 cubic meters.
As a result, you should find out the amount of reinforcement that will be required for reinforcement.
For example, the diameter is 13 mm, the casting has 2 horizontal threads, i.e. 2 rods,
vertically the rods will be located every half a meter. Since the perimeter of the
foundation is known in advance – 30 m, then 30 x 2 (horizontal rods) = 60 m.
Calculation of vertical rods: 60 x 2 + 2 = 122 rods (120 intervals of 0.5 m and two at the edges).
To this amount should be added one more rod per corner of the building. In total there will be 126 rods.
For example, the height of the rod is 60 cm. As a result: 126 x 0.6 = 75.6 m.
At the end of the calculations, we calculate the materials for the formwork.
Let’s imagine that the formwork will be constructed from boards 3 cm thick, 7 m long and 25 cm wide.
Let’s find out the area of the side surfaces: the perimeter should be multiplied by the height of the casting,
and then by 2 (this is a margin without taking into account the reduction of
the internal example against the external one): 30 x 0.3 = 9 square meters.
Area of the formwork board: 7 x 0.25 = 1.75 square meters; 9/1.75 = 5.14.
Let’s round the calculated number 5.14 to 6. This will be the required number of boards – 6 boards 7 meters long.
After carrying out the calculations, you will receive a rounded amount of the required materials.
Foundations
Reinforcement of strip foundation drawings and videos
The foundation is the load-bearing support of the building,
taking the load from the structures and distributing it evenly to the ground.
The most common type of foundation is a strip foundation; reinforced concrete
or concrete blocks are combined into a closed loop.
A prefabricated structure has a number of disadvantages,
so most often a monolithic base is installed.
Correct reinforcement of a strip foundation is an important category for strength parameters,
compliance with which is necessary for the construction of
buildings in accordance with the provisions of
building regulations and safety regulations.
househill.ru
During operation, the foundation is subject to the load from the main frame of the building,
from the movement of internal objects and the force of frost heaving from the soil.
Frost heaving should never be ignored; it can destroy any foundation.
Due to the deformation of the support, the walls begin to loosen,
the building can quickly fail and lose its primary characteristics.
Description of the procedure
For reinforcement, material with longitudinal placement is used.
Most often these are products made of hot-rolled steel of class A3.
When the height of the building’s base is above 15 cm, the structure immediately
needs transverse and vertical reinforcement. Rods made of smooth A1-class
reinforcement with a diameter of 6 to 8 mm are installed vertically.
Connecting rods of perpendicular planes with single clamps provides higher rigidity to the frame.
When forming a single frame, the calculation is done in such a way that the longitudinal rods are placed inside.
To determine the step for reinforcing a strip foundation, you must refer to SNiP 52-01-2003,
which prescribes taking into account the following factors in longitudinal reinforcement:
diameter of reinforcing bars
filler fraction in concrete solution
direction and plane of reinforcement placement
concreting method.
Based on the above requirements, the distance from one reinforcing frame
rod to another cannot be less than the diameter of these elements (lower limit – 25 mm).
When placing rods transversely in the frame, the pitch cannot exceed 300 mm.
Everyone knows that the reliability of a future home depends
directly on the strength of the foundation; it is he who must take
on the entire load and “carefully” transfer it to the soil layers.
The construction of a strip foundation involves laying a reinforced
concrete strip completely around the perimeter of the object.
A reinforced concrete strip is laid under the walls
inside and outside the building along the perimeter.
It is used in houses with walls made of brick,
stone and high-density concrete (over 1250-1300 kg/cub.m).
If it is laid correctly, then it is able to correctly “redistribute”
the load on the walls and permanently eliminate the appearance of cracks.
Before construction, you need to select a suitable foundation.
At the same time, the lowest prices for a strip foundation
should not “play” a decisive role, since an incorrect foundation
design and excessive savings on everything can lead to misalignment,
cracks, or even uneven shrinkage and breakage of the building.
Foundations
There is no special choice in structural reinforcement products,
and it is not needed. Standard rolled rods do an excellent job of reinforcing any foundation,
and their thickness and arrangement are selected depending on the design features of the foundation.
Whatever the reinforcement is, it is laid only according to two schemes:
longitudinal reinforcement occurs when it is necessary to minimize tensile loads;
such reinforcement is placed below and above the foundation screed, for this
use a rod of grade A3 with a relief surface;
Longitudinal-transverse reinforcement is performed when everything is expected from the foundation,
and especially in cases where its height exceeds 1.5 m at least in some places.
In the second case, more powerful reinforcement of class A1 from a rolled rod is used,
connecting the longitudinal with transverse knitting wire. Welding is not used in this case.
When tying reinforcement, it is very important to maintain the distance to the outer
surfaces of the foundation, to the formwork and cushion. There are several ways to control this,
but the easiest way is with bricks. It is necessary to ensure that the metal rods do not touch the ground,
otherwise corrosion will negate all reinforcement efforts. The minimum distance from the r
od to the ground should be at least 6-8 cm. Only after this can you fill the pillow.
This is the simplest and most academic case, when reinforcement passes
only along the bottom of the foundation. This is explained by the fact that a foundation
buried to the freezing depth is built when the soil is stable and the building does
not require a second floor. In this case, the reinforcement is rather of an insurance nature.
In this case, A3 reinforcement and smooth A1 reinforcement are used for cross-linking.
All dimensions specified in the standards remain valid in this case.
In the event that the soil on which construction is being carried out is
unreliable and the load on the foundation is higher, more serious measures
should be taken to strengthen the foundation. In these cases,
the width of the foundation is taken to be one and a half to two times larger,
and when reinforcing, the transverse rods are set to be equal in
diameter to the longitudinal ones. In this case, the entire structure is
connected with knitting wire; the use of welding is also not encouraged here.
It is also recommended to increase the number of horizontal rods,
reducing the distance between them to 20 cm.
Сборный ленточный фундамент представляет собой конструкцию из железобетонных блоков,
которые соединяются друг с другом бетонным раствором.
В отличие от устройства обычного ленточного фундамента,
вам придется заплатить дороже, так как без помощи тяжелой техники здесь не обойтись.
Зато такое основание отличается прочностью и возводится значительно быстрее.
Advantages and disadvantages of a prefabricated foundation
Before we begin the debriefing, let’s find out the positive and negative sides.
So, you can weigh everything and be convinced or dissuaded of the rationality
of using a prefabricated structure.
Advantages of the foundation:
Unlike a monolithic strip foundation, the installation is much faster.
A continuous strip of concrete will take at least a month to dry. In the prefabricated version,
FBS are already ready for use. And considering that you will need to work with special equipment,
this will speed up the process.
Once you have erected the structure, you can begin building the box at home.
Each element is of excellent quality and has standard characteristics according to GOST.
The foundation is durable and strong.
Disadvantages of the foundation:
Due to the seams between the slabs, it will be difficult for you to lay the waterproofing material.
If we compare it with a monolithic tape, it is slightly inferior in strength.
The cost of the device is significantly higher. You will have to hire powerful mechanized equipment.
If you ask any engineer where the construction of a foundation begins,
he will confidently say that the first step is to make a plan and the corresponding drawings.
This stage is key. As for the prefabricated foundation, its plan is simply irreplaceable.
Without it, you simply will not be allowed to carry out construction work.
The thing is that this plan contains all the information, structural characteristics
and technology for laying the base. In addition,
the document notes the exact number of blocks and other elements.
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