We will talk about what the concept of "cramped conditions in construction" means and what factors influence this process. Let's talk about the details of the work and the change in the estimate. We will answer many other interesting questions in this article.
General view
Explanations about cramped conditions in construction should begin with a number of factors that affect the construction of buildings and structures within the city. These include:
- Intensity of pedestrian and vehicle traffic near construction activities.
- Accounting for the nature of underground utilities: its branching.
- Presence of structures (residential complexes or industrial enterprises), as well as the preservation of various kinds of landscaping during construction.
- The presence or absence of the possibility of storing materials on the territory allocated for construction.
- Compliance with safety at the construction site, taking into account the rules and regulations for the operation of mounting cranes.
Thus, from the aboveit follows that the definition of cramped conditions is reduced to various kinds of interference that affect the time and financial costs in the construction of a particular object. Difficulties can also be temporary and auxiliary buildings, heavy construction equipment and everything that is an obstacle to the implementation of the necessary activities for the construction of the facility.
Description of the building (reconstruction) process
In order to start construction, you need to get some documents:
- Comprehensive urban planning decision on where the developed facility will be located (built).
- Decision of the architectural plan (concept). This includes the following stages: the place where the building will be located; its three-dimensional model; setting boundaries of the territory; interaction with the environment.
Thus, the cramped conditions for the construction and reconstruction of buildings (residential purposes) are classified into internal and external interference.
For the first option, the main base is the shortage of space within the boundaries for the organization of the construction process, which is preliminarily approved by the general construction plan. What caused it? There are several reasons:
- Small distance between existing site facilities as well as occupied buildings within a given boundary.
- If the existing engineering communications pass near the building.
External cramped conditions
They are characterized by the following features:
- Short distance from ongoing construction to buildings that are in operation outside the site, but fall within the range of mechanisms.
- The width of the road outside the construction site is not sufficient to deliver the necessary machinery or materials to the construction site, but is still used for these needs.
- Impact of the hygienic conditions of residential complexes that are located outside the boundaries of the installation work (for example, noise).
Therefore, there are problems that can be eliminated according to the envisaged design. These include:
- Communications that can be corrected (remade). This includes both underground and terrestrial species.
- Demolition of buildings that are in operation.
A cramped crane, depending on its operation, should be limited to four movements in various combinations according to the safety protocol:
- arrow turning;
- moving the crane along the crane track;
- hook suspension outreach;
- raising and lowering the hook block.
It is recommended to place an action plan by zones in the installation cabin on the display: working, preventive and prohibited.
When one of the indicated combinations enters an undesirable zone, the system must issue a warning sound signal, after which the crane mechanism drives must switch manually or automatically to reduced speeds.
In this regardthe crane needs to be prepared, that is, to set up the whole system:
- install sensor;
- mount or position the microprocessor device in a convenient place;
- carry out the necessary work in the electronic circuit to turn on the crane;
- set up the program, test and run the system.
Foundation
Building in cramped conditions is based on laying the foundation. In order to avoid low-quality structures, great attention is paid to this stage. It is necessary to calculate all the risks associated with the construction (for example, the movement of underground plates, which may affect the subsidence of the base of the building in the future and lead to the rapid destruction of the building).
Therefore, if the objects are located at a small distance from each other, then an identical foundation should be used, the same as for previously erected structures. This means that in terms of its composition and level of deepening, the foundation of a new building should be the same as the already built buildings. Otherwise (different properties of the poured foundation on which the object is located), it is necessary to study in detail and analyze the influence of the foundations of both buildings on each other.
What can happen with different types of foundations? In cramped conditions, for example, between a pile and slab base, the abutment zone under the grillage of the old building can lead to loosening of the soil, which will weaken the bearing capacity of the piles, which will lead to partial destruction of the old structure.
For close interaction of twoobjects (new and old), provided that identical foundations are used, pits should not be excavated up to the wall of the existing foundation without protective measures. Otherwise, this may lead to raising the soil from under the sole of the existing foundation into the pit. To avoid such embarrassment, which will be very expensive, it is necessary:
- Dig a pit along the length of the existing foundation in small pockets, approximately 3-4 meters to the corner of the building.
- Lay the foundation in a chain: first in the first dug mini-pit, and then in subsequent pits.
In case of different depths of the foundations, it is definitely worth using a separating sheet pile wall at the junction, thanks to which stability is checked after digging a foundation pit for a new foundation.
Piles and their purpose
A sheet piling wall (or nearby) is a continuous waterproof structure that acts as a barrier against water entering the pit or washing it out. Based on the definition, if the cramped conditions in construction are carried out on soft ground between high-rise buildings, then a separating sheet pile wall is installed according to safety protocol.
There are several types of such fences:
- bored reinforced concrete;
- drive-in reinforced concrete;
- Larsen sheet pile (metal).
In the construction process, laying in cramped conditions is most often carried out using bored monolithic sheet piles. The dependence of its diameter and the deepening of the pit(the number of levels underground) varies between 32-100 cm and more. For example, if the depth is over 4.5 m, then a pile pile and ground anchors are installed, the diameter in this case should be 32 cm.
Warehouse and its role
Properly organized work in cramped conditions implies high speed of construction or reconstruction of an object. To do this, you need to allocate a place where stocks of various materials necessary for construction will be stored. They are delivered to the site in specialized containers and packaging. All structures enter the action zone and are mounted using transport mechanisms. Strictly Prohibited: Storing long products on site and shipping materials in bulk.
Large assembly of structures is allowed (exceptional cases), if available:
- feasibility study and development of a project of specialized equipment, which together provide a position during the installation work of enlarged structures;
- relevant construction project documentation regarding the foundation or method of fixing deep excavations;
- reporting surveys for engineering-geological or technical studies of the building;
- programs for monitoring underground spaces and structures that are subject to geotechnical expertise.
Production process under limited conditions
Cramped working conditions - this is the execution of installation work, which is associated with many factors,negatively affecting and complicating the production process. As a result:
- increasing time to perform technological operations;
- rarely, but overspending of building materials has been noticed;
- slowing down the time process of finding equipment at the production site;
- ultimately, the actual costs of the organization (contractor) for the entire complex of construction works increase.
For the term "cramped conditions" among specialists, the concept of MDS (methodological documents in construction) is quite well known. There are a number of regulations that are necessary for the construction of facilities. One of the most common documents is MDS 35 on cramped conditions. What does it mean? Let's take a closer look.
The document reflects the methodology that sets the price tag of construction products throughout the Russian Federation. There are a lot of estimated standards that determine the cost of the entire complex of works. They are built in a certain sequence:
- type of work or cost;
- social object;
- launch complex;
- construction queue;
- full complex for the construction of buildings.
The calculation is described in the MDS on constrained conditions:
- direct costs;
- overhead;
- estimated costs.
For the first group (direct), the cost of resources that are needed to perform various types of work: material, technical and labor (budgeting) is taken into account. The second group is responsible for spending on the organization (construction,installation), that is, it is involved in the creation of general production conditions for maintenance, organization and management. The estimated amount includes: funds that are needed to cover individual expenses in a generalized form, for production development, the social sphere and material incentives. The IBC on cramped conditions in construction recommends a list of the following conditions:
- construction of structures for the needs of workers who are dismantled at the end of the construction process;
- rent of temporary premises, which will subsequently be liquidated;
- moving structures for various purposes (for example, warehouses);
- expenses and rent for current repairs of inventory buildings of the constructor type (collapsible);
- presence of closed (heated) or open (unheated) warehouses for storing materials that are brought to the site for construction work;
- construction of multifunctional workshops (production);
- installation of temporary power plants for special occasions and needs;
- installation for cleaning surface water sources.
Communications
Laying communications is an important point in construction, which applies to the gas pipeline and water supply. Using one of these conditions as an example, let's look at the whole process in detail.
The cramped conditions of the gas pipeline mean that before direct laying there should be a ready and thought-out action plan, in which in detailall risks are studied and taken into account. Installation takes place in two ways: ground and underground.
Important. Wires that are underground must be in a bunding. The parameters of the gas pipeline under the ground are calculated based on thermal and other technical characteristics. When laying communications for gas on specific sections of the road, namely between buildings and under their arches, it is necessary to use gas pipelines with a pressure of 0.6 MPa in accordance with approved standards (at a distance of 5 m), and when combined with single buildings (auxiliary), it is allowed:
- reduce by 1/2 the distance between objects in cramped conditions;
- no more than 1/4 under special conditions.
Gas pipelines above the specified pressure are laid in the following cases:
- when introduced into the industrial zone;
- in an undeveloped part of the village.
In both the first and second cases, the installation must comply with the layout of construction objects relative to the plan of the village in which the installation is carried out. As for above-ground laying, it is not always used, but only in certain cases:
- along the perimeter of the inner walls of buildings of residential complexes;
- on specific sections of the road;
- on the border of obstacles;
- when crossing technical support networks.
It is carried out only if there is a justification and access of unauthorized persons to the gas system is limited. In soil or hydrological conditions, a gas pipeline can be laid with a system of barragefacilities.
Estimate and its calculation
Cramped conditions in the estimate include accounting for increasing factors to standard labor costs.
Payment in this case depends on the type of work performed and can be taken into account in each position or according to the final estimate provided. Also, the estimate can be displayed in two forms at the same time: separately for each position and total.
Reason for estimates calculation:
- Setting a task for the project, which is issued by the customer.
- Decisions provided for in the project documentation, taken by the head of the company.
The customer's tariff is determined based on the analysis of the estimate documentation, which contains information about the contract work. With this information, you can:
- carry out calculations of the pricing policy proposed by the contractor;
- form constants: the cost at the end of the conducted contract bidding with the execution of the protocol of all agreements for the construction of the facility in the required form.
Taking into account the MDS on cramped conditions, the cost of a building or construction is determined as part of preliminary studies, with the allocation of a price for each individual stage, production facility and civilian residential building. Also, in some cases, it can be individually determined:
- construction cost;
- construction expansion;
- resuming;
- technical modernization of the base of the construction industry and other facilities in this area.
Construction cost calculations withjustifications for investments, it is desirable to draw up for a specific type of construction for each type of work. This will greatly facilitate the financial part of the issue.
How is the number determined?
The concept of a correction factor and the definition of constrained conditions are very closely intertwined. Thus, the coefficient in the production of installation construction works increases depending on a number of factors. When erecting a building in difficult production conditions, the norms of this indicator are established regarding time costs and prices for the corresponding work:
- For operating enterprises with technological equipment from 1, 1 to 1, 2; at metallurgical, chemical or oil enterprises from 1.1 to 1.25.
- In cramped conditions in construction companies from 1, 1 to 1, 15.
- In warm rooms 1, 1.
- In the security zone of air systems of power equipment and objects under voltage from 1, 1 to 1, 2.
In conclusion
So, we found out that the cramped conditions mean the restriction of the possibility of using mechanization, materials, products, structures, as well as the impossibility of a rational organization of the site due to the presence of a complex of obstacles.
The cramped conditions of the existing urban development suggest the presence of spatial obstacles at the construction site and the adjacent territory, restrictions on the width, length, height and depth of the size of the working area and undergroundspace, locations for construction machines and vehicle passages, an increased degree of construction, environmental, material risk and, accordingly, enhanced security measures for workers in the construction industry and the resident population.
Estimated documentation can be developed by the design organization on its own, if it is provided for in the contract. Specialists who develop documents according to the estimate set the size of the correction factor, guided by the characteristics of cramped conditions, which must be displayed in an act of a certain form.
